The magnetic viewer makes the mysterious tracks recorded onto the tape visible
We use a Sigma Hi-Chemical MV-95 magnetic viewer in order to aid our digitisation work. By pressing the viewer against the tape we are able to read the magnetic information recorded on it. The reader helps us to visually identify the position of the recorded tracks on the tape, and enables accurate playback during digitisation. Magnetic readers can also help us to identify potential problems with the tape, for example if a track has been partially erased, because it will show up on the viewer.
We receive tapes that are in varying states of repair and disrepair. Sometimes the person who made the recording kept the tapes in impeccable, temperature controlled conditions. Inscribed on the boxes are dates and lists of who performed, and what instrument they played. The tapes often feature detailed notes about the number of tracks recorded, whether they are in stereo or mono and if they used noise reduction technology. Digitisation, in such cases, does not usually pose great challenges.
At the other extreme are tapes recorded by people who never wrote anything down about how they made their recording. This means the people doing the digitising can be left to do a lot of guess work (particularly if that person has since died, and can’t tell you anything about the recording). A lack of informative metadata about the tape does not necessarily create migration difficulties: recordings can be very straightforward like, for example, a ½ track stereo recording of a single voice.
It is essential that the appropriate head is used to read the magnetic information recorded onto the tape.
Problems can however arise when recordings have been made in an idiosyncratic (and inconsistent) manner. For example (and in exceptional circumstances) we receive single magnetic tapes that have a mixture of track formats on them which include four track multi-track, ½ and ¼ track mono and ½ and ¼ track stereo.
In such cases it can be hard to discern the precise nature of the recordings using the ears alone. Often such recordings don’t sound ‘quite right’, even if it is not exactly clear what the problem is.
Rather than relying on speculation, using the magnetic reader gives 100% confirmation about where tracks are recorded on the tape, and therefore helps us to replay the tape using the appropriate playback heads, and therefore digitise it accurately.
The history of amateur recording is peppered with examples of people who stretched technologies to their creative limit. Whether this comes in the form of hours spent trying things out and learning through doing, endlessly bouncing tracks in order to turn an 8-track recording into a 24-track epic or making high quality audio masters on video tape, people have found ways to adapt and experiment using the tools available to them.
One of the lesser known histories of amateur home recordings is making high quality stereo mixdowns and master recordings from multi-track audio tape onto consumer-level Hi-Fi VCRs.
We are currently migrating a stereo master VHS Hi-Fi recording of London-based indie band Hollow Hand. Hollow Hand later adopted the name Slanted and were active in London between 1992-1995. The tapes were sent in by Mark Venn, the bass player with Slanted and engineer for these early recordings that were recorded in 1992 in the basement of a Clapham squat. Along with the Hi-Fi VHS masters, we have also been sent eight reels of AMPEX ¼ tapes of Slanted that are being transferred for archival purposes. Mark intends to remix the eight track recordings digitally but as of yet has no plans for a re-release.
When Mark sent us the tapes to be digitised he thought they had been encoded with a SONY PCM, a mixed digital/ analogue recording method we have covered in a previous blog post. The tapes had, however, been recorded directly from the FOSTEX eight track recorder to the stereo Hi-Fi function on a VHS video tape machine. For Mark at the time this was the best way to get a high quality studio master because other analogue and digital tape options, such as Studer open reel to reel and DAT machines, were financially off-limits to him. It is worth mentioning that Hi-Fi audio technologies were introduced in the VHS model by JVC around 1984, so using this method to record stereo masters would have been fairly rare, even among people who did a lot of home recording. It was certainly a bit of a novelty in the Great Bear Studio – they are the first tapes we have ever received that have been recorded in this way – and take it for granted that we see a lot of tape.
Using the Hi-Fi function on VHS tape machines was probably as good as it got in terms of audio fidelity for those working in an exclusively analogue context. It produced a master recording comparable in quality to a CD, particularly if the machine had manual audio recording level control. This is because, as we wrote about in relation to PCM/ Betamax, video tape could accommodate greater bandwidth that audio tape (particularly audio cassette), therefore leading to better quality recordings.
One of our replacement upper head drums
VHS Hi-Fi audio is achieved using audio frequency-modulation (AFM) and relied on a form of magnetic recording called ‘depth multiplexing‘. This is when
‘the modulated audio carrier pair was placed in the hitherto-unused frequency range between the luminance and the colour carrier (below 1.6 MHz), and recorded first. Subsequently, the video head erases and re-records the video signal (combined luminance and colour signal) over the same tape surface, but the video signal’s higher centre frequency results in a shallower magnetization of the tape, allowing both the video and residual AFM audio signal to coexist on tape.’
Challenges for migrating Hi-Fi VHS Audio
Although the recordings of Hollow Hand are in good working condition, analogue masters to VHS Hi-Fi audio do face particular challenges in the migration process.
Playing back the tapes in principle is easy if both tape and machine are in optimum condition, but if either are damaged the original recordings can be hard to reproduce.
A particular problem for Hi-Fi audio emerges when the tape heads wear and it becomes harder to track the hi-fi audio recording because the radio frequency signal (RF) can’t be read consistently off the tape. Hi-Fi recordings are harder to track because of depth multiplexing, namely the position of the recorded audio relative to the video signal. Even though there is no video signal as such in the playback of Hi-Fi audio, the video signal is still there, layered on top of the audio signal, essentially making it harder to access. Of course when tape heads/ drums wear down they can always be replaced, but acquiring spare parts will become increasingly difficult in years to come, making Hi-Fi audio recordings on VHS particularly threatened.
In order to migrate tape-based media to digital files in the most effective way possible, it is important to use appropriate machines for the transfer. The Panasonic AG-7650 we used to transfer the Hollow Hand tapes afforded us great flexibility because it is possible to select which audio tracks are played back at any given time which meant we could isolate the Hi-Fi audio track. The Panasonic AG-7650 also has tracking meters which makes it easy to assess and adjust the tracking of the tape and tape head where necessary.
As ever, the world of digitisation continues to generate anomalies, surprises and good stories. Who knows how many other video/ audio hybrid tapes are out there! If you do possess an archive collection of such tapes we advise you to take action to ensure they are migrated because of the unique problems they pose as a storage medium.
Even before a tape is played back prior to transfer the packaging can tell you a lot about how and where it has been stored, and what it was used for.
Whether the boxes include sparse notation or are covered in stamps from countries across the world, the places where the tape has been, and the personality of its owners, sometimes shines through.
The packaging can also provide insight about the cultural context of tape, like this 3″ spool that was marketed to link ‘absent friends’. The space on the back of the box to affix a stamp (that remains empty), shows how these tapes were posted to friends and family who lived far away from each other, prior to the introduction of the telephone.
The back of the tape indicates how it was used to record family gatherings, with precious recordings of ‘Grandma’s voice’ and ‘all of us’ together on rare occasions such as ‘Boxing Day 1962?’ And perhaps further recordings five years later, with the warning of the tape’s special content: ‘Elaine Don’t You Touch’, preventing further use.
An important part of digitisation work we do is tape restoration. Often customers send us tape that have been stored in less than ideal conditions that are either too hot, cold or damp, which can lead to degradation.
In the excellent Council on Library and Information Sources’ report on Magnetic Storage and Handling (1995), they set the ideal archival storage conditions for magnetic tape at ‘significantly lower than room ambient (as low as 5 centrigade)’, with no less than 4 degrees variation in temperature at 20% room humidity. They suggest that ‘the conditions are specifically designed to reduce the rate of media deterioration through a lowering of the temperature and humidity content of the media.’
Of course most people do not have access to such temperature controlled environments, or are necessarily thinking about the future when they store their tape at home. Sometimes manufacturers recommended to store tape in a ‘cool, dark place’, but often tape is not adorned with any such advice. This leads to us receiving a lot of damaged tape!
As we are keen to emphasise to customers, it is possible to salvage most recordings made on magnetic analogue tape that appear to be seriously damaged, it just requires a lot more time and attention.
For example, we were recently sent a collection of 3” multi-track tapes that had been stored in fairly bad conditions. Nearly all the tapes were degraded and needed to be treated. A significant number of these tapes were AMPEX so were suffering from binder hydrolysis, a.k.a. sticky shed syndrome in the digitisation world. This is a chemical process where binder polymers used in magnetic tape constructions become fragmented because the tape has absorbed water from its immediate environment. When this happens tapes become sticky and sheds when it is played back.
Baking the AMPEX tapes is a temporary treatment for binder hydrolysis, and after baking they need to be migrated to digital format as soon as possible (no more than two weeks is recommended). Baking is by no means a universal treatment for all tapes – sticky shed occurs due to the specific chemicals AMPEX used in their magnetic tape.
Cleaning shedding tape
Other problems occur that require different kinds of treatment. For example, some of the 3” collection weren’t suffering from sticky shed syndrome but were still shedding. We were forewarned by notes on the box:
The tapes recorded on TDK were particularly bad, largely because of poor storage conditions. There was so much loose binder on these tapes that they needed cleaning 5 or 6 times before we could get a good playback.
We use an adapted Studer A80 solely for cleaning purposes. Tape is carefully wound and rewound and interlining curtain fabric is used to clean each section of the tape. The photo below demonstrates the extent of the tape shedding, both by the dirty marks on fabric, and the amount we have used to clean the collection.
You might think rigorous cleaning risks severely damaging the quality of the tape, but it is surprising how clear all the tapes have sounded on playback. The simple truth is, the only way to deal with dry shedding is to apply such treatment because it simply won’t be able to playback clearly through the machine if it is dirty.
Loss of lubricant
Another problem we have dealt with has been the loss of lubricant in the tape binder. Tape binder is made up of a number of chemicals that include lubricant reservoirs, polymers and magnetic particles.
Lubricants are normally added to the binder to reduce the friction of the magnetic topcoat layer of the tape. Over time, the level of the lubricant decreases because it is worn down every time the tape is played, potentially leading to tape seizures in the transport device due to high friction.
In such circumstances it is necessary to carefully re-lubricate the tape to ensure that it can run smoothly past the tape heads and play back. Lubrication must be done sparingly because the tape needs to be moist enough to function effectively, but not too wet so it exacerbates clogging in the tape head mechanism.
Restoration work can be very time consuming. Even though each 3″ tape plays for around 20 minutes, the preparation of tapes can take a lot longer.
Another thing to consider is these are multi-track recordings: eight tracks are being squeezed onto a 1/4″ tape. This means that it only takes a small amount of debris to come off, block the tape heads, dull the high frequencies and ultimately compromise the transfer quality.
It is important, therefore, to ensure tapes are baked, lubricated or cleaned, and heads are clear on the playback mechanism so the clarity of the recording can realised in the transfer process.
Now we’ve explored the technical life of the tape in detail, what about the content? If you are a regular visitor to this blog you will know we get a lot of really interesting tape to transfer that often has a great story behind it. We contacted Richard Blackborow, who sent the tapes, to tell us more. We were taken back to the world of late 80s indie-pop, John Peel Sessions, do it yourself record labels and a loving relationship with an 8 track recorder.
A Short History of BOBby Richard Blackborow
Back in 1983 I was a 17 year old aspiring drummer, still at school in North London and in an amateur band. Happily for me, at that time, my eldest brother, also a keen musician, bought a small cottage in a village called Banwell, which is 20 or so miles outside of Bristol, near Weston Super Mare. He moved there to be near his work. The cottage had a big attic room and he installed a modest 8-track studio into it so that he could record his own music during his spare time. The studio was based around a new Fostex A8 reel-to-reel machine and the little mixing desk that came with it.
The equipment fascinated me and I was a regular visitor to his place to learn how to use it and to start recording my own music when he wasn’t using it.
Skip forward a couple of years and I am now 19, out of school, deferring my place at university and in a new band with an old friend, Simon Armstrong. My brother’s work now takes him increasingly abroad, so the studio is just sitting there doing nothing. Simon and I begin to write songs with the express intention of going to Banwell every time we had a decent number of tunes to record. Over the next ten years it becomes part of the routine of our lives! We formed a band called BOB in 1986, and although we still lived in London, we spent a lot of time in that small studio in Banwell – writing, recording demos, having wild parties! By this time my brother had moved to the US, leaving me with open access to his little studio.
The band BOB had modest success. John Peel was a keen fan and a great supporter, we toured loads around the UK and Europe and made lots of singles and an album or two, as well as recording 5 BBC sessions.
To cut a long story short, we loved that little studio and wrote and recorded some 300 songs over the ensuing 10 years…the studio gear finally dying in about 1995. Most recordings were for/by BOB, but I also recorded bands called The Siddeleys and Reserve (amongst others).
The tapes we recorded have been lying around for years, waiting to be saved!
Recent interest in BOB has resulted in plans to release two double CDs. The first contains a re-issued album, all the BBC sessions and a few rarities. The second CD, planned for next year, will contain all of the BOB singles, plus a whole CD of the best of those demos we recorded. It was for this reason that all of those old tapes were sent to Adrian to be transferred to digital. I now have a studio near my home in West Cornwall, close to Land’s End, where I will be mixing all the material that Great Bear have been working on. The demos map our progression from pretty rubbish schoolboy aspirants to reasonably accomplished songwriters. Some of the material is just embarrassing, but a good chunk is work I am still proud of. We were very prolific and the sheer number of reels that Adrian has transferred is testament to that. There is enough material there for a number of CDs, and only time will tell how much is finally released.
Listen to the recently transferred Convenience demo
This is a bit of a rarity! It’s the demo (recorded on the little 8-track machine in Banwell) for a BOB single that came out in 1989. It’s called Convenience and I wrote and sang it. This early version is on one of the tapes that Adrian has transferred, so, like many of the rest of the songs, it will be re-mixed this winter for digital formats and released next year.
If you want the latest news from BOB you can follow them on twitter. You can also pre-order the expanded edition of their 1991 album Leave the Straight Life Behind from Rough Trade. It will be available from the end of January 2014. A big thank you to Richard for sending us the photos, his writing and letting us include the recording too!
The Greatbear studio always has a wealth of interesting material in it, that somehow have survived the test of time.
From racks stacked full of obsolete audio and video tape machines, to the infinite varieties of reel-to-reel tape that were produced by companies such as Scotch, E.M.I. and Irish Recording Tape.
As objects in themselves they are fascinating, instilled with the dual qualities of fragility and resilience, the boxes worn at the edges and sometimes marked with stamps, identificatory stickers or scrawled, handwritten notes.
A selection of ‘audio letters’ sent to us by a customer
The latest addition to the Great Bear Studio – the Fostex Model 80 8 Track Recorder
As lovers of magnetic tape and obsolete media, we keep our eyes open for people who remain attached to the formats most have forgot.
A recent film posted on Vimeo features the creative life of part time chef, noise musician and tape DJ Micke, also known as ‘The Magnetist’.
The film follows the Stockholm-based artist through his life as a ‘tapeologist.’ From demagnetising tape in order to create soundscapes, to running a club night comprised of tapes scavenged from wherever he can find them, Micke demonstrates how the audio cassette remains a source of inspiration within counter culture.
The wider resurgence of cassettes is evident from the forthcoming Cassette Store Day, an event that will be marked in record stores in the UK, USA, Europe and South America.
So what’s behind the sub-cultural obsession with the audio cassette tape? Perhaps it is no more complex than novelty value and nostalgia. It may however be evidence of the persistence of analogue technologies in an era where digital technologies appear to have colonised our relationship to sound and vision.
Is there a yearning to resist the ways digital media shapes how we listen to music, both at the level of sound quality, and the promiscuous skipping through mp3 files?
You simply can’t do that with tape. You have to rewind, fast forward or listen the whole way through. Its a mechanical process, often shrouded in hiss.
What is certain, fashion or no fashion, the wheels on the Great Bear tape machines will keep turning.
In archiving, the simple truth is formats matter. If you want the best quality recording, that not only sounds good but has a strong chance of surviving over time, it needs to be recorded on an appropriate format.
Most of us, however, do not have specialised knowledge of recording technologies and use what is immediately available. Often we record things within limited budgets, and need to make the most of our resources. We are keen to document what’s happening in front of us, rather than create something that will necessarily be accessible many years from now.
At the Great Bear we often receive people’s personal archives on a variety of magnetic tape. Not all of these tapes, although certainly made to ensure memories were recorded, were done on the best quality formats.
Recently we migrated a recording of a wedding service from 1970 made on C-120 audio cassette.
Image taken using a smart phone @ 72 dpi resolution
C60 and C90 tapes are probably familiar to most readers of this blog, but the C-120 was never widely adopted by markets or manufacturers because of its lesser recording quality. The C-120 tape records for an hour each side, and uses thinner tape than its C90 and C60 counterparts. This means the tape is more fragile, and is less likely to produce optimum recordings. Thinner tapes is also more likely to suffer from ‘print-through‘ echo.
As the Nakamichi 680 tape manual, which is pretty much consulted as the bible on all matters tape in the Great Bear studio, insists:
‘Choosing a high quality recording tape is extremely important. A sophisticated cassette deck, like the 680, cannot be expected to deliver superior performance with inferior tapes. The numerous brands and types of blank cassettes on the market vary not only in the consistency of the tape coating, but in the degree of mechanical precision as well. The performance of an otherwise excellent tape is often marred by a poor housing, which can result in skewing and other unsteady tape travel conditions.’
The manual goes on to stress ‘Nakamichi does not recommend the use of C-120 or ferrichrome cassettes under any circumstances.’ Strong words indeed!
It is usually possible to playback most of the tape we receive, but a far greater risk is taken when recordings are made on fragile or low quality formats. The question that has to be thought through when making recordings is: what are you making them for? If they are meant to be a long term record of events, careful consideration of the quality of the recording format used needs to be made to ensure they have the greatest chance of survival.
Such wisdom seems easy to grasp in retrospect, but what about contemporary personal archives that are increasingly ‘born digital’?
A digital equivalent of the C-120 tape would be the MP3 format. While MP3 files are easier to store, duplicate and move across digital locations, they offer substantially less quality than larger, uncompressed audio files, such as WAVs or AIFFs. The current recommended archival standard for recording digital audio is 24 bit/ 48 kHz, so if you are making new recordings, or migrating analogue tapes to digital formats, it is a good idea to ensure they are sampled at this rate
‘in the midst of an amazing revolution in computer technology, there is a near total lack of systems designed with digital preservation in mind. Instead, we have technology seemingly designed to work against digital preservation. The biggest single issue is that we are encouraged to scatter content so broadly among so many different and changing services that it practically guarantees loss. We need programs to automatically capture, organize and keep our content securely under our control.’
The issue of format quality also comes to the fore with the type of everyday records we make of our digital lives. The images and video footage we take on smart phones, for example, are often low resolution, and most people enjoy the flexibility of compressed audio files. In ten years time will the records of our digital lives look pixelated and poor quality, despite the ubiquity of high tech capture devices used to record and share them? Of course, these are all speculations, and as time goes on new technologies may emerge that focus on digital restoration, as well as preservation.
Ultimately, across analogue and digital technologies the archival principles are the same: use the best quality formats and it is far more likely you will make recordings that people many years from now can access.
In a recent blog article on the Presto Centre website, Richard Wright argues that ‘the audiovisual collections of the 20th century were analogue, and we are now at a critical time for considering the digital future of that analogue content.’ He goes on to say, emphatically:
‘All analogue audio and video formats are obsolete. Digital content walks through walls, travels at the speed of light, can be in many places at the same time, and can (with care) be perfectly copied, again and again. So digitisation has become the solution to the obsolescence of all analogue audio and video formats.’
Although careful not to make too clinical a statement, he bookmarks 15 April 2023 as the date when analogue obsolescence really kicks in.
A major problem is finding spare parts for machines after manufacturers stop producing them. Many components were made according to very precise specifications that are hard to make from scratch. When machines and their parts wear out it will therefore be difficult, if not impossible, to keep them working.
This means that the cost of transfers will rise due to machine scarcity. At an institutional level this may lead to selective decisions about what gets digitised and what doesn’t.
Writing for music magazine The Wire, Numero Group’s Rob Sevier and Ken Shipley describe how ‘vinyl’s violent sales spike has been a lonely bright spot in what has been a 14 year deterioration in sales of recorded music’.
Yet the resilience of vinyl and other contemporary fringe uses of analogue media, such as the cassette tape and floppy disk, is not enough to stop the march of digitisation. For experts like Wright the digital future for the majority of people is inevitable, irresistible even, given how it enables collections to be open, replicable and accessible.
Yet committing to digital technologies as a preservation and access strategy does not solve our information problems, as we have been keen to stress on this blog. There is also a worrying lack of long term strategy for managing digital information, a problem which is ever more pronounced in film preservation where analogue tape is still marked as the original from which digital copies are made.
It is clear that the information we create, store and use is in transition. It probably always has been. The emergence of digital technologies has just made this a pressing issue, not only for large institutions, but for people as we go about our day to day lives.
‘Digitise now!!’ is Richard Wright’s advice – and of course we agree.
‘It seems we are living in an age in which practically every dream comes true. At no time in the past have so many scientific discoveries and inventions changed our way of life and the face of the world. Yes, we live in the age of science! Maybe we are forgetting to be awed, or are we so used to acquainting ourselves with the new that we seem to take anything for granted nowadays?’
This is the opening paragraph to A Comprehensive Booklet on BASF Magnetic Recording Tape, published c.1965 by the German company BASF.
The booklet, that we will feature more of in later posts, offers advice and instructions on how to record sound on magnetic tape.
While in today’s culture we may well have forgotten ‘to be awed’ by sound recording technology, there was a time when home recording was an extremely novel activity. As our recent post about Brian Pimm-Smith’s tapes demonstrates, sound recording was done by enthusiasts – it was by no means an everyday activity.
Tape recording clubs were however very popular in the 1960s-1970s, with groups forming all around the country.
Sound artist Mark Vernon describes how ‘dedicated amateurs would meet and swap tips, exchange recordings, enter competitions and arrange activities such as field recording trips. Eager members would lug heavy reel-to-reel recorders around the countryside, to church concerts, fire stations, airports and carnivals to capture the sounds around them.’
The excitement of recording sound on a ‘mysterious little reddish-brown ribbon’ is clear from reading the BASF manual. There is no shortage of awe for the ‘magic tape that practically does everything from writing out cheques to guiding missiles in space.’
In contemporary western culture the use of recording technologies has become as common as eating or breathing. Mystery and magic are words not often used to describe our laptops, phones or tablets. Yet it may well be worth remembering how mysterious and magic technology can be. That the things we take for granted as part of our everyday lives were once new inventions that radically transformed perceptions and our ability to document the world we live in.
As the BASF manual enthused, ‘the multitude of different impressions in the acoustic world…are just as beautiful and gratifying as those of the visible world [and] can now be conserved for all posterity.’
We were recently sent a collection of recorded interviews with residents of Hebden Bridge, a mill town in the Pennines. They were recorded on regular, domestic tapes of the mid-1970s, the kind that were sold in shops such as Woolworths or WHSmith.
As magnetic cassette tapes go, these cheaper tapes can often deteriorate at a fast rate because they were aimed at a mass consumer market, and therefore not made with longevity in mind. These tapes however were in excellent condition, and no issues arose in the digitisation process.
Here is what Susie Parr told us about the project behind the tapes, and the publishing plans for the material later this year. We were very happy to be part of a creative project that will enable the stories to be shown to new audiences because of digitisation.
‘In 1975 photographer Martin Parr moved to Hebden Bridge, a mill town in the Pennines, with some friends from art school in Manchester. In a project that was to last five years, he started photographing the area, documenting a traditional culture and way of life that were slowly declining. Susie Mitchell, who also lived in Hebden Bridge, wrote about the people and places that Martin photographed. Together they built up a record of the day to day lives of mill-workers, game-keepers, coal miners, hill-farmers and chapel-goers. As part of their research, Susie and Martin would tape record their conversations with some of the characters they met. Thirty years later, the elderly audio tapes have been digitised and the photographs and texts are going to be published by Aperture in a book called The Non Conformists. In September, an exhibition will open in London.’
Below is an audio snippet of one of the tapes. This is a raw unprocessed version, notice the tape hiss inherent in these types of recordings. Sympathetic noise reduction to reduce this type of noise, can be process on these file if necessary.
The main work of Greatbear is to make analogue and digital tape-based media accessible for people living in a digital intensive environment. But once your tape-based media has been digitised, is that the end of the story? Do you never need to think about preservation again? What issues arise for information management in the future, and how do they relate to our actions in the present?
This year (2013) the National Archives in the UK are facing a huge challenge as the ’20-year rule‘, in which the government will be releasing records when they are 20 years old, instead of 30, comes into effect. A huge part of this process is the digitisation of large amounts of material so they can be easily accessible to the public.
What does this have to do with the digitisation of tape you may be wondering? Well, mostly it provides food for thought. When you read the guidelines for the National Archives’ digitisation strategy, it raises many points that are worth thinking about for everyone living inside an information intensive environment, professional archivist or not. These guidelines suggest that many of the problems people face with analogue media, for example not being able to open, play or use formats such as tape, floppy disks or even digital media, such as a cd-r, do not go away with the move toward wholesale digitisation. This is summed up nicely in the National Archive’s point about digital continuity. ‘If you hold selected digital records that are not yet due for transfer, you will need to maintain their digital continuity. This means ensuring that the records can be found, opened, understood, worked with and trusted over time and through change’. This statement encapsulates the essence of digital information management – the process whereby records are maintained and kept up to date with each technological permutation.
Later on in their recommendations they state something which may be surprising to people who assume that digitisation equates to some form of informational omnipotence: ‘Unlike paper records, digital records are very vulnerable and will not survive without active intervention. We cannot leave digital records on a shelf in an archive – they need active management and migration to remain accessible in the long term.’ These statements make clear that digital records are just as vulnerable as their analogue counterparts, which although subject to degrading, are in fact more robust than is often assumed.
What is the answer to ensuring that the data we create is usable in the future, is there an answer? It is clear on whatever format we choose to archive data there is always risk involved: the risk of going out of date, the risk of vulnerability, the risk of ‘not being able to leave them on the shelf’. Records, archives and data cannot, it seems, simply look after themselves. They have to adapt to their technological environments, as much as humans do.
From U-matic to VHS, Betacam to Blu Ray, Standard Definition to High Definition, the formats we use to watch visual media are constantly evolving.
Yet have you ever paused to consider what is at stake in the changing way audio-visual media is presented to us? Is viewing High Definition film and television always a better experience than previous formats? What is lost when the old form is supplanted by the new?
At Greatbear we have the pleasure of seeing the different textures, tones and aesthetics of tape-based Standard Definition video on a daily basis. The fuzzy grain of these videos contrasts starkly with the crisp, heightened colours of High Definition digital media we are increasingly used to seeing now on television, smartphones and tablets.
At Greatbear we always have one foot in the past, and one foot in the future. We act as a conduit between old and new media, ensuring that data stored on older media can continue to have a life in today’s digital intensive environments.
As well as analogue tape, at Greatbear we also migrate digital tape to digital files. Digital media has become synonymous with the everyday consumption of information in the 21st century. Yet it may come as a surprise for people to encounter digital tape when we are so comfortable with the seemingly formless circulation of digital information on computers, at the cinema, on televisions, smartphones, tablets and other forms of mobile media. It is important to remember that digital information has a long history, and it doesn’t need to be binary or electronic – abacuses, Morse code and Braille are all examples of digital systems.
Digital Betacam tapes were launched in 1993 and superseded both Betacam and Betacam SP. Betacam remains the main acquisition and delivery format for broadcasting because there is very little compression on the tape. It is a very reliable format because it has a tried and tested mature transport mechanism.
While Digital Betacam is a current broadcast format, technology will inevitably move on – there is often a 10 year lifespan for broadcast media, as the parent company (SONY in this case) will cease to support the playing machines through selling spare parts.
We were sent some Digital Betacam tapes by Uli Meyer Animation Studios who are based in London. Uli Meyer make 3 and 2 D commercials, long and short films and TV commercials. 5-10 years ago the company would have had Digital Betacam machines, but as technology develops it becomes harder to justify keeping machines that can take up a lot of physical space.
Workflow in broadcasting is also becoming increasingly ‘tape less’, making digital tape formats surplus to requirements. Another issue facing the Digital Betacam is that it records information in Standard Definition format. With broadcasters using High Definition only, the need to transfer digital information in line with contemporary technological requirements is imperative for large parts of industry.
We’ve been a bit quiet since last year on our blog here primarily because we have been processing a large, ongoing audio archiving digital migration job for Mood Media Ltd
In essence audio archiving, digital migration, transfer or digitisation, whatever term you prefer, is conceptually simple: one analogue or digital format is moved to another, usually digital, format. It is in the details of this process that things can get complex – requiring experience, specialised tools and often custom-built solutions.
This job has many factors – not just attaining the best analogue transfers, but also addressing the organisation of such a large amount of 10.5″ reels, their digital management once migrated and the creation and management of metadata.
The archive, dating from the 1950s up to the early ’90s, even though it had been stored in less than ideal conditions, is in generally good condition. An interesting and often fantastic-sounding collection of recordings and music are evident all recorded at 15ips in mono, stereo and some encoded with Dolby A noise reduction.
There are specific issues with some tapes that are not uncommon with older audio tape:
Binder hydrolysis or sticky shed syndrome (SSS) has affected a significant proportion of the archive in particular Ampex branded tapes from the 1980s onwards.
Some glue used in spices from the 1980s spreads over time and tends to stick layers of tape adjacent to the splice together. This can be a very frustrating problem which rarely damages the tape permanently, but affects the tape tension on certain sections so that head to tape contact is momentarily lost and a very obvious audio glitch noticed.
The analogue side is important to get correct initially but the management of the data is critical with such a large number of reels and individual artists and tracks. Each batch of tapes would be catalogued in a .csv file. The digital audio transfers were split into individual tracks which then had to be renamed based on the data in the .csv file. This was handled by some php coding which matched the metadata supplied with the files, checking for inconsistencies then renaming the .wav files on one of our servers.
This type of customised workflow can be tricky to setup initially and find the balance between accuracy and speed but once done a smooth workflow is possible maintaining high quality, accuracy and value.
Tascam, Fostex and Yamaha sold cassette multitrack recorders in the golden days of home recording in the 1980s and ’90s. The 4 track format was especially popular but an 8 track format was also developed that squeezed even more out of the small tape width of the cassette.
We love these cassette formats and their accessibility helped start many musicians’ careers. Unfortunately one of the best 8 track machines, the Tascam 238 Syncaset also suffers from a common and frustrating problem that renders most of these machines useless over time, the dreaded direct drive capstan motor failure…
The 238 and other 8 track and high quality stereo tape decks, the 688 and 122 MkII and III, used a direct drive capstan motor for precise speed control and reduced speed variation or wow and flutter (w/f). The circuit that controls this motor fails in certain ways causing lack of speed control and in our case the capstan motor wizzing away at a crazy speed, not the 9.5 cm/sec that it should do.
This here is the culprit – you can see the attempted repairs which didn’t ultimately work.
One common failure is that the surface mount electrolytic capacitors fail or their capacitance changes to such an extent to cause speed problems. These can be changed for standard through hole caps but you do need to be very careful as the tracks are damaged very easily – good tools are essential.
The other point of failure in the circuit is the BA6304F SO16 IC – we even changed this but the motor still didn’t turn!
There was some suggestion from previous repairers that the grease at the end of the capstan flywheel hardens over time. increasing the friction and causing problems with the circuit.
This can become frustrating quickly, especially when you have a large archive of cassettes to digitise.
When we can’t repair we reluctantly do the next best thing and buy the whole replacement part but this is another exercise in frustration. Teac parts and Teac UK don’t have any european supply of this capstan motor (part no. 53700075-01) anymore as of November 2011. Interestingly about 6 months ago they did at around £60 GBP, then about 3 months ago they had one left at £160 GBP!
Lots of emails later to Teac US, Teac Canada and Teac Japan there seem to be a nice stock still on shelves somewhere and at reasonable prices UNTIL you ask them to ship to the UK when you discover they can’t do this and I’d need to go through Teac UK!!! I’m pretty persistent but I gave up finally even though some of the support staff tried to be pretty helpful.
We find support for older machines from the original manufacturers is not good generally and unreasonably expensive when you can find it. This is similar across audio and video, semi-pro and professional products. Some companies are easier to deal with and have a better parts situation than others, but stockpiling machines, parts, manuals and obsolete knowledge is the best course of action.
What we finally did that worked and was a good solution was purchase 3 Tascam 122 Mk III stereo cassette decks which use the same but a later revision of the capstan motor, (part no. 53700121-00).
One machine was donated for the cause and the capstan motor removed, modified and refitted in the 238. The 122 motor has a few factory extras, such as these resistors, shown here:
You also need to solder / desolder the speed pads, to change the motor speed from 4.8 cm/s to 9.6 cm/s that the 238 needs to run at.
It’s also a good idea once you’ve got the capstan motor apart to clean the old grease from the seat, check the end float which can be adjusted using the screw shown on the left and apply new grease to the capstan end.
Put it all back together – be careful to solder the wires to the motor to the correct pads – they’re different on the 122 and test… Ours worked almost perfectly.
As the transport hadn’t been used for a while the reel motor would intermittently stop as if sensing the tape end. This can sometimes be loose counter belts but on the 238 it’s a digitial counter. We cleaned up the leaf switches on the transport top and also sprayed a small amount of deoxit into the inside of the reel motor. A bit more use and it finally worked to spec…
Cassette tapes run at a very slow speed of 17⁄8 inches per second (ips) with a very small track width of 1.59mm
Cassette decks when they left the factory or a service centre should have been aligned to a standard reference for the position of the record and play heads. Unfortunately they often weren’t all the same and over time the alignment can drift, get knocked out or manually ‘fiddled with’ by an owner.
What this means is that unless you’re playing back your tape on the machine it was originally recorded on, you may not be getting the maximum quality as the angle of the head to the recording or azimuth will not be optimal.
Without calibration tones recorded at the start of the tape (which is very unlikely on most domestic cassette tape recordings), you must set the playback azimuth manually. A few high end tape decks, namely those made by Nakamichi, either had a easily accessed Azimuth Adjust or could even automatically adjust this throughout the tape. The Nakamichi Dragon was one such tape deck and could be the best, if working well, for high quality playback.
If you want to transfer or convert a cassette to CD and adjust the azimuth yourself this is the easy way to do it:
Look at the tape path (everything the tape will move across) and if it looks brown and dirty get some isopropyl alcohol and give it a good clean with a cotton bud.
If you haven’t demagnetised your deck for a while now would be a good time to do it..
Power up your cassette deck, which hopefully works correctly and doesn’t have too much speed instability!
Pop your tape in the cassette well and start to play.
Turn your amplifier’s volume up and if you can put it in Mono.
Now, look under the tape machine’s playback or combined record and playback heads you should see a small screw or nut possibly with anti tamper paint on it.
Using an appropriate tool, turn this nut or screw a little left or right while listening to the audio.
You should hear the recording, especially if it has a lot of high frequency content such as cymbals etc. get bright and dull sounding or more technically get more in or out of phase.
Your aim is to get the most in phase or bright sounding playback.
Sounds better now?? Great, start to record using you favourite computer audio software. We like SoX for the control but there’s a huge range out there.
We often get sent Digital Audio Tapes or DATs for transfer to .WAV computer files. As these recordings are already digital or ‘born digital’ the process should be straightforward. Our audio interface cards accept the SPDIF or AES digital audio stream from the DAT machine and record this as a WAV or BWAV file. This file can then be burnt as a CD or delivered digitally on a hard drive or removable media.
The big problems though come with the tape that these digital recordings are made on. The tape is only 3.81 mm wide and moves at a very slow 8.15 mm/sec. The tape is also very thin at 13 microns. The recording system and transport used is helical scan just like in video recording but with the very slow tape speed and small tape dimensions any defects or problems with the tape can result in many errors which may not be correctable by the error-correcting system of the DAT machine.
One problem we’re starting to see more and more are tapes that snap. The tape pictured above was a D120 which was never recommended by the DAT machine manufacturers but was still often used for its extended recording time. This tape snapped without warning a quarter of the way through the recording. There were no outward signs or potential problems just a sudden clean break on a diagonal.
To recover this tape it could have been spliced with splicing tape of the correct width like in analogue recording but there is a high risk if not done perfectly of irreparable damage to heads on the drum. Even with this type of repair some of the material would have been lost. A safer solution is to rehouse each spool in another shell. This lets you recover as much as possible from the tape, without the risk of head damage.
Whichever solution you decide, the DAT shell must be disassembled. A small crosshead screwdriver needs to be used to remove all the case screws. There are two hidden ones, accessed by sliding part of the cassette shell down:
You can now carefully lift both halves of the DAT shell apart, making a note of the tape path inside the shell. Be careful not to touch the tape with your bare skin as fingermarks and grease can cause head to tape contact problems and audio errors and dropouts.
Once a common sight in Radio stations around the world, the NAB Cartridge machine or Fidelipac was used for short jingles and announcements, sometimes even for longer recordings. Using a similar sized cartridge to a domestic 8 track machine the NAB cartridge was different in that the pinch roller was not in the cartridge but would hinge up in the player and hold the tape against the capstan. Running at 7.5 inches per second (ips) compared to 3.75 ips in domestic cart machines the recording and reproduction quality good be very good but it was the ease of use and cueing ability offered by these machines that made them so useful in broadcasting.
We have Sonifex cart machines that while very well built do have rubber parts that will degrade over time and reduce the transport performance. Luckily we have some of the last remaining stock of new pinch rollers, motors and capstan drive belts.
The pinch roller in one of our machines had become quite hard and the rubber shiney over time. A pinch roller in this state may not hold the tape as securely and could also have flat spots both leading to increased wow and flutter and poor tape handling. These pinch rollers also have high quality cartridge bearings pressed into their shell. Over time these loose their lubrication, wear, become rough feeling and will also add to poor tape handling.
Older, fragile and valuable tape must be handled and used carefully. A ‘chewed’ tape caused by a poorly maintained tape transport in any tape machine, audio or video is a disaster and hard to recover from perfectly.
Both halves of the cart machine case need to be removed to easily change the pinch roller. While the access is good and the machine, in this case a Sonifex microHS, had been designed for easy servicing the pinch roller is still a little fiddly to get to so I removed the transport from the main chassis.
To remove the pinch roller a small slightly hidden C clip must be removed you can see in the image above the slot machined into the roller shaft where it sits and holds the roller. This is hard to remove as the plastic bush on top of the roller stops you getting a small screwdriver in. I managed to remove the C clip with some fine circlip pliers. Be careful not to loose the clip if you don’t have spares, they fly away very easily!
Now the new roller can be placed on the shaft. It’s a good idea once all the transport is out to give everything a good clean with IPA.
On this machine, the castan drive belt was quite slack so a new one was fitted, which is easy now the transport is removed. First though the capstan flywheel and motor pulley were cleaned of all the old rubber belt residue that tends to accumulate over time.
The last thing to do is check the pinch roller pressure. This is important to as to high or too low will increase wow and flutter, increase wear to the bearings and capstan surface and give poor tape handling. Due to the design of these NAB cart machines, the pinch pressure needs to be checked with a special cartridge. The pinch pressure is then adjusted from a screw pot on the top PCB seen outlined below in green.
We have two of these excellent machines in addition to our Sony APR 5003s and Studer A80s. The Tascam BR-20 was Tascam’s last and top of the range 1/4 inch reel to reel tape machine and available in two track stereo and stereo with centre timecode option.
The capstan drive in the BR20 is belt driven by a wide belt. Both belts in our machines looked OK but we’ve replaced all roller bearings, belts and pinch rollers in both of our machines anyway as a matter of course. These parts are still available from Teac UK via Acoustic Services on 01-844-347600.
Below is a simple explanation of how to change the capstan belt.
Unplug machine from mains power and move to a strong stable base.
Remove cross head screws from the rear panel and lift plate off. Depending on the type of plug in your country you may not be able to remove it completely.
You’ll now be able to see the capstan motor and it’s control board attached to it.
Remove the 4 cross head screws and gently lift the analogue audio output board away from the machine as in the picture above.
We now need to remove the whole capstan motor assembly with the control board still attached. Remove the 4 cross head screws right at the front of the assembly, NOT the six nearest to you when looking at this image.
Carefully unclip the 4 cable connectors from the motor control board. The other connector cannot be removed from the board and must be removed where it connects to the other board.
The whole assembly can now be lifted out from the machine. Be careful to not snag any cables and remember to unclip the black cable ties.
You’ll now be able to unclip the control board from the assembly by carefully compressing the black clips with some needle nose pliers.
Now remove the six cross head screws holding the capstan motor assembly together. This is the only way to remove and refit the capstan belt. There’s not enough room to do it any other way!
Now you can remove the old belt and capstan shaft. It’s a good idea to clean the capstan with IPA where the old belt has run and reapply a little grease to the bearing end of the capstan.
Fit your new belt and reassembly is the reverse of dissasembly! Be careful though to not drop the screws into regions you can’t get them out of – luckily there aren’t that many on this machine but a long magnetic screwdriver is very useful.. just don’t get it anywhere near the headblock and heads!
This is something you don’t see everyday! An almost unused and boxed 1/4″ 2 track reel to reel tape machine, a Tascam BR20 one of their highest quality machines sometimes installed with a Timecode head for broadcast and editing applications.
This machine somehow turned up at an IT Recycling centre in Essex but is now in much safer hands transferring tapes, in particular a very large archive of library music on 10.5″ NAB reels owned by Mood Media Ltd.
As you can see this machine is in its original box, with packaging and first look at the heads show almost no head wear but some nasty oxide that took a while to clean off.
This machine needed little work to bring it back to spec, a new capstan belt, pinch roller, tape tension and speed setting and a full calibration.
The capstan belt change is the subject of another blog post here..
The regular service of analogue machines which will involve the mechanical alignment then electrical alignment / calibration is really important if you’re attempting to get optimum transfers and reduce any risk of damaging the potentially fragile tape.
While some of our machines are serviced by others we like to regularly check them and have gradually brought our regular servicing in house. Of course this needs specialised tools, test tapes and gauges, often totally unavailable new now.
On a lucky eBay day I happened to win one of these beauties, an Information Terminals M-300 gauge. This enables you to accurately set the tape guide height and also the head stroke. It is a universal gauge and can be used across many decks.
Nakamichi tape deck owners have had a hard time doing this part of their servicing as the original Nakamichi gauges are very very rare now as is this.
A member of the naktalk mailing list though recently borrowed our gauge and has had it measured and will soon have a small batch CNC machined and made available. These remanufactured gauges will have a few small modifications to improve the design.
Thanks to Willy at www.willyhermansnervices.com many more tape deck transports will be able to be aligned correctly.
We’ve been honored recently to have won a large contract to help in the digital migration of an extensive educational video archive by the transfer from U-matic archive copies to uncompressed video files.
While the archive had been stored in an suitable environment and rarely if at all played, they had not survived well. The Sony branded tapes from the 1970s and 1980s all exhibited binder hydrolysis or sticky shed syndrome. We were still able to get good transfers though using our range of U-matic machines, particularly the Sony BVU-950P and For-A Time Base Corrector.
We’ve recently been involved, with Mobray Woodwards Solicitors, in the audio transfer of important evidence in a local Crown Court case.
Even given the poor quality or the recordings, made on the slowest tape speed of 1.2 cm/s we were able to make transfers to CD which were clear and understandable with CD track markings for easy access to specific sections of the audio.
Microcassettes, until recently, were used regularly for voice recording in small, portable dictaphone type of machines. Their fidelity is not high but when used for voice it is usually acceptable.
Greatbear are able to transfer all formats and speed of microcassette in addition to 1/2 speed standard cassettes that were common for voice recording of interviews and meetings in the police service, inquests, etc.
I use eBay alot. I have to, nobody makes new tape machines anymore and about two or three years ago it took over from the local freeads papers as a way to sell things you didn’t want.
I recently bought an old Teac X7 4 track 1/4″ reel to reel. Seemed like a good deal and I took a chance. With large heavy items I always ask politely if they can ensure it’s packed with lots of bubble wrap in preferably two boxes. I even offer to send the packaging myself if they haven’t budgeted for that or can’t be bothered to wrap that well!
This is what I received after a few days of waiting. The seller seemed excited, saying he’d specially bought a box that cost over £10…
Reel to Reel packaging bottom
The whole of the bottom of the box had cracked and fallen away. If it hadn’t of been for the nice Parcelforce people who lined it with a bit of cardboard I wouldn’t have got anything.
There was a Teac X7 in it but it didn’t look pretty and is a perfect example of how heavy items can destroy themselves and the packaging if not packed correctly.
15 inches per second (ips) and 7.5 ips speeds are normally transferred on, our pride and joy, one of two Studer A80s. We also have a Tascam BR20 and several Revox A77s for backup. The slower speeds and 4 track mono stereo formats are catered for by Teac and Sony machines.
30 ips, 15, 7.5 and 3.75 can also be transferred on our Sony APR 5003.
We take pride in making sure these machines are calibrated and cleaned before each transfer.
Quite often we receive tape in poor condition, frequently a result of splicing tape ‘drying out’ as it’s a bit like sellotape and the splices breaking as the tape is played.
We are able to clean, resplice and repair tape before transfer.
Prices are competitive but not published here as we’ve found each job is different and needs certain attentions that need to be quoted for on an individual basis. We are happy though to offer an assess / listen service, as many customers don’t know what’s on their tapes and either don’t have a machine or their old machine is broken.
Recent work has included many valuable family history 5 inch reels. Remember tape is fragile, very susceptible to magnetic fields and doesn’t last forever. It’s worth transferring it or getting it transferred now to keep your memories safe.
You can see a more comprehensive list of all our audio equipment in our studio here:
