You’ve been asked to digitize recordings in your collection and don’t have any idea where to start. There are several resources on this site which might be of use.
What I use is shown on my facility page. That\’s one of the main reasons it is there. If I’m using it, it’s because I like it or it solves a problem for me. If I’m not using it, either I don’t have an opinion about it, won’t spring for it, or don’t like it.
\”Noise Reduction\” is a potentially confusing topic, partially because it has come to be used to mean two different things.
When reviewing old tapes, they may be marked in various ways to indicate their noise reduction compression, or processing. As of this writing, there are no software plug-ins that accurately mimic the action of the hardware compander acting as an expander. We use actual companders from the original systems when restoring tapes made with these systems.
We currently handle nine different formats from four manufacturers and are always on the lookout for more. Most manufacturers sold a variety of systems tailored to the needs of different kinds of transmission/recording channels
See our special page under formats (click here) to see some of the information we’ve gathered about noise reduction techniques used over the years. Check back as we uncover additional formats and information.
The National Recording Preservation Board has made available a new document Capturing Analog Sound for Digital Preservation. It is an excellent summary document, and we’ve added it to our information page.
Demagnetizing tape heads and recorder parts is a ritual of magnetic recording. If any part that touches the tape is magnetized beyond a certain level it will begin degrading the tapes played on it.
While early machines may have had an issue with magnetization, most late-model machines rarely become magnetized. The source for real information on this is Jay McKnight’s Magnetic Reference Lab Web site.
The question seems to regularly arise on mailing lists and chat rooms about Dolby and dbx plug-ins. I don’t think it will happen and I added that comment and some hopefully helpful operational hints to my noise-reduction page, here.
We have recently completed our second audio tape restoration seminar.
We had three great attendees. One of them, Andy Kolovos of the Vermont Folklife Center shared these comments:
I want to thank you again for the workshop. I’m certainly still assimilating stuff in my head, but it was terrific. I learned so much… Through these workshops you’re doing the archival field a huge service. The ability to tap into your experience and take what we learn back into the world with us enriches everyone. Because you are willing to share your knowledge, skill, and passion with those of us who love these audio resources, work with them on a daily basis and are eager to learn all we can about their care, more of the aural heritage of the world will survive into the future. Your generosity is wonderful! Thanks again!
You can see the brochure for our November 2005 seminar here.
Comments from the November 2005 seminar are in the brochure for the May 2006 seminar.
The first three of the four days we were together about 13 hours a day (including dinner at various restaurants) and we didn’t stop talking audio. We covered a LOT of ground and the questions and discussions were great.
UPDATE: March 2008…Cold playback (see this article) seems to work with the two tapes mentioned in this article, 3M 175 and Sony PR-150. We’ve had confirmation from several sources who have tried it.
For a current list of degrading analog tapes, click here.
Fellow restorer Doug Pomeroy sent me a photocopy of Herman Burstein’s “Tape Guide” article from the May 1977 issue of “Audio” magazine. Robert Coe of Manchester, CT, wrote in saying “…some of these [Scotch 175] tapes have developed a high frequency chatter or squeal which is mechanical and can be stopped by rubbing the tape with a light coating of talcum powder. The squeal only occurs on the Scotch 175 tape even when used with several different brands of tape machine.” Burstein replied, “Yes, I’ve heard other complaints about squeal, sometimes involving Scotch tape which is not surprising in view of 3M’s large share of the market, but yours is the first complaint about 175 tape.” He went on to say that another 3M tape exhibited this but it was limited to the batch and 3M replaced it.
We do not recommend the talcum powder approach as it overall has proven to be a bad idea since it gums up the machines and increases spacing loss more than other solutions.
Doug is currently having a joyous bout with 175 but Art Shifrin apparently has a proprietary mechanical fix to the tape deck that allows playing 3M 175.
We are researching more about 175 and hope to have updates. The use of decamethylcyclopentasiloxane (D5 or cyclomethicone) has had mixed results with 175 and Sony PR-150, another known squealer.
There have been rumours that Nakamichi used a different cassette standard than the other manufacturers. This is not really the case. Everyone thought they were using the same 3180/120 or 3180/70 microsecond equalization as specified in IEC Pub 60094-1, 1981. There is further discussion from 2010 here.
As I understand the history, both Nakamichi and STL in the late 1970s discovered that when they made calibration tapes based on the published time constants in the standards, their response showed that the then-common BASF alignment tapes were approximately 4 dB high (hot) at 16 kHz.
It is assumed that BASF, who made the calibration test tapes made an error in calibrating their reproduce heads’ response in one of two areas:
With budget limitations, it appears that oral histories are being recorded with little thought to their long-term preservation. While this appears to have been the case in the past as well, with purchasing agents buying the cheapest white-box tape that they could find, continuing this into the digital age needs to be reconsidered.
The cost savings in using bargain-basement digital speech recorders are offset by the labour required to reformat these files upon their receipt by an archive and also the fidelity of the recording suffers, and with fidelity, intelligibility also suffers.
DSS was an industry standard agreed upon by Olympus, Grundig, and Philips in 1994.
While the Ampex Mastering Equalization is well documented on this site and at the MRL site, and standard equalizations are detailed at the MRL site on page 3 of this document, I am always amazed when I discover additional, supported tape equalizations. Certainly there have been proposals for alternate equalizations. Jay McKnight has published a paper (here) about this. This post is about something different.
Teac Corporation, with their X-2000M reel-to-reel tape recorder included a button called “Extra Efficiency” to be used with then-new tapes that had double the coercivity of standard reel-to-reel audio tapes. This changed the recording equalization (and the bias and possibly the reference levels) to better make use of the new tapes to improve the overall sound.
What was fascinating here is not that they used the IEC standard equalization of 35 μs at 15 in/s, which was standard in Europe, but that they also invented their own standard and used 35 μs at 7.5 in/s as well! Not content with that, they invented yet another standard of 50 μs for 3.75 in/s.
The NagraMaster and StellaMaster equalizations are also non-standard and were probably the most widely adopted equalizations after AME, but who knows how widely used this Teac EE equalization was and who knows what tapes are in archives that had this equalization incorrectly applied.
I have been informed that it was only intended for the consumer market.
I received an email asking me to discuss tape splicing. Most of my work is now repairing old splices so I try and butt them together as best I can in an Edi-Tall block and use the blue Quantegy splicing tape (which will become harder to find with Quantegy exiting the business). I will not be evaluating a replacement for several years as I bought a large supply a few years ago.
I received a query from Sweden today asking
I have a Studer machine with butterfly heads with which I’d like to reproduce
tapes recorded with normal two track heads. Theoretically, how much more noise,
in dB, would I get from playing the “empty” part of the tape?
Let’s look at the assumptions.
My friend Susan Kitchens and her brother took their parents to the StoryCorps recording session in Los Angeles a few weeks ago. She blogged it here. One of the neat things is that between her article and the discussion she and I had in the comments, we have a good handle on most of the equipment that was used in the trailer. It’s a good selection in my opinion and shows how simply good-quality recording systems can be set up. Further discussions from a StoryCorps representative have shown how clever the setup is.
Jill Hurst-Wahl in her excellent blog “Digitization 101” asks this question and provides some good answers with reasons. You can read it here.
I received a query from a gentleman in Europe about 1.875 in/s 4-track tapes. He was frustrated in finding a good machine for transferring them. Apparently, they have many of these tapes. Here are my suggestions.
Perhaps the easiest answer is to find a Studer-Revox C274 with low speed options. They were made.
Two other options.
The question of how to format hard disks (i.e. what file system to use on them) for easy interchange is another FAQ. A recent experience brought home the fact that it is more complex than one might hope. The computer industry is headed towards universal readability, but it is not there yet. The most-able-to-be-read-and-written format appears to be FAT32, although my friend Eric Jacobs makes the point that NTFS is a more robust hard disk file system, and I have to agree.
I didn’t think I needed to write this post, but it appears that someone purchased a Racal Store 4DS Instrumentation Recorder at least partially because I mentioned it, hoping that it would work as a four-track recorder for creating music.
It seems some people new to tape are confused over how to align a tape recorder. This is the abbreviated version.
If you want to record on a tape recorder (and I do not recommend doing that these days as you’re just generating more tapes that will need to be transferred later) the first thing to do is get the playback correct.
In 2006, I wrote a blog post (here) called “Let Sleeping Tapes Lie: What to do with poorly wound tapes”. For years, tape experts have been suggesting that it is not as good an idea to rewind tapes as was originally thought. This was partially based on the fact that most rewinding in archives was done on the oldest, junkiest machines so as to not wear out the good machines. Unless rewinding is done on high-quality tape transports, it is indeed counter-productive.
We continue to receive poorly wound tapes and are able to play them successfully. So why the quandary now? The reason is that I read portions of another Bharat Bhushan book, Mechanics and Reliability of Flexible Magnetic Media, 2nd Edition, New York, Springer, 2000. Referring to several research papers he makes a compelling case that tapes should be rewound annually if subject to storage environment fluctuations and every 3.5 years if kept in a climate controlled storage area.
Once again, an interesting post on Jill Hurst-Wahl’s Digitization 101 Blog. She started by discussing tape backup issues. In the comments, I discussed my solution of using multiple spinning disks. Another commenter, Ike, provided an extensive review of file system options and his opinions on what works (and doesn’t) for long-term storage. Ike’s comment is fascinating and has lots of food for thought. Here is the post.
The Training for Audiovisual Preservation in Europe (TAPE) Project has just published an excellent Audio Tape Digitisation Workflow document here. It is authored by Juha Henriksson of the Finnish Jazz & Pop Archive and Nadja Wallaszkovits of Phonogrammarchiv, Austrian Academy of Sciences. It is aimed at the newcomer but still addresses all of the major points without being overwhelming.
It appears that many old acetate tapes when played on high-quality audio recorders will suffer spoking when left in a play wind condition. I have discussed this problem here. Since posting that, I have taken one of my Racal Store 4DS recorders and removed the heads to save them from wear and now use that to re-spool any tape that shows spoking when played on a Studer A80, Sony APR-5000, or Studer A810.
The format page for 0.15 inch wide tape has a drawing (click for large version) that clearly shows that mono cassettes have one wide track and stereo cassettes split this track in half and add a small guard band. Most mono cassette recorders follow this format. It turns out that the mono Marantz PMD201 uses a two-channel head and records dual mono. Most other mono recorders seem to follow the standard.
While this is a theoretical problem, few if any good mono recorders are available for reproducing these tapes anyway, so most of us in the domain transfer field use good quality stereo machines for all cassette transfer work.
UPDATE 2012: While it is often possible to sum the channels if the Dragon finds proper azimuth, on many low-quality tapes this proper azimuth is not achieved. Now that azimuth correction (at least the time delay portion) is available for a reasonable price in iZotope RX2 Advanced, I have found that after correcting for time delay between channels that I can now sum both (if they are worthy of it) and reduce the noise prior to applying the noise reduction plug-in.
For a current list of degrading analog tapes, click here.
Teaching people how to identify tapes that are suffering from sticky shed syndrome is often difficult.
I would like to propose that a careful inspection of how the tape comes off the pack may be a good way. Please provide comments as to how it’s working for you.
The tape should come off the tape pack at a precise tangent to the tape. If the tape starts to adhere and not pull off straight, that is a sure sign that the tape needs baking.
Of course, don’t bake acetate tapes even if they show this indicator, but on the last batch of questionable SSS tapes, I’ve been looking at this and it’s a fair indicator, and it seems to show at the outer edge of the pack.
More than one “test” or “factor” is needed to be sure, but this one is looking good.
Another almost sure sign of SSS is brown oxide and black back-coat.
We have just seen a modification on the Sticky Shed Syndrome (SSS) failure mode. This is a case where the back-coat of the tape is turning to powder. The oxide was brown but yet it left a black, non-sticky accumulation of powder on the reproduce head. This accumulation would drastically reduce the high frequency response of the system due to spacing loss. We did bake the tape and we’re not sure that helped significantly, although it did not appear to make the problem worse. We would NOT recommend baking these tapes in the future. Ultimately, Pellon wiping of the mag coat during transfer after several pre-wipes for the length of the tape solved this.
Agfa PEM-526 exhibited this odd behaviour. The tape was recorded in 1990.
There is also a discussion about PEM-469 showing similar behaviour here.
For a current list of degrading analog tapes, click here.
For many years, I had been in favour of the Primera Z1 small optical disc printer. When Primera discontinued this several years ago, I was not pleased and purchased two as spares, hoping at least the ribbons would continue.
It appears that I am not alone in thinking this is a good product as it has resurfaced as the U-Print CDP78, now in black, and available from many online distributors. The cartridges appear to be interchangeable with the Primera. I can now suggest that this is a good alternative for safe, long-lasting, and reasonably attractive text labeling of CDs and DVDs. It appears that the Teac P11 is also similar. The last time I checked, the Casio required manual rotation of the disk, rather than the Primera’s automatic rotation.
Please provide me with any feedback pro or con—preferably as comments to this post.
I consider myself fortunate to have been one of many recipients of Peter Copeland’s generous assistance while working with some challenging tapes. I was saddened by his too-early passing in 2006.
The British Libary has now published his Handbook (click here).
We have pulled the list of degrading analog audio tapes out of the blog postings (which age) and put this information into the Formats hierarchy under Analog Audio Tapes, click here. Please note that we have fudged the hierarchy by starting the title with a hyphen, so it sorts to the top of the Analog Audio Tape grouping, above 0.15″ cassettes.
We hope to update this as we come across more types. January 2009 was, sadly, fruitful in finding at least some batch(es) of two tapes from 1990 (Agfa PEM 526) and 2003 (Emtec SM911) are degrading. The Emtec SM911 was thought to be more-or-less immune from this disease. As of this writing, it has been confirmed that batch number B0134007 was involved.
My paper on “Tape Degradation Factors and Challenges in Predicting Tape Life” that was published in the Fall 2008 issue of the ARSC Journal is now available online. Click here.
The Zoom H2 HandyCorder is perhaps the lowest-cost digital recorder on the market that provides reasonable and useful results. While I have a Sound Devices 722 for my more serious work, I bought the Zoom to test it out to see if it could be part of a simple tape digitization system for archives on a budget who wish to do the work themselves. It does this reasonably well.
As with much equipment–and especially with lower-cost equipment–the performance specifications and the actual operational data is not published. There are reports of the H2 clipping on the line inputs in some of the reviews and it appears that a lack of understanding how the inputs were configured exacerbated that situation.
There is nothing wrong with the line inputs on the H2. BUT there are some caveats: