Restoring, Archiving and Solving Puzzels

September 2018 Blog
By Park Peters, Owner and Chief Recording Engineer at Audio Park Recording Studio

Note from the Archives: As Park himself said about this article, “It’s pretty geeky!”  The Science of Mind Archives asked Park to write an article about preserving our old reel and cassette tapes so we can all understand what it takes to preserve our archival treasures–and the importance of having a knowledgeable professional on the job. It is a bit longer than our usual blog articles and we feel this is invaluable information so we can assess our collection and prioritize what pieces of our history to bring back to life for us all to learn from and enjoy.

First things first. Here’s a bit of my background. I was born totally blind in 1959. As I was growing up and going to school, books came to me in three ways, in Braille, on reel tapes, and on records. Because of this, I learned how to operate record players and tape recorders by age seven. Because of my interest in music, I learned how to record myself and others over the next few years. During that time, books also became available on Cassette tapes. Today, there are hundreds of thousands of titles available as downloads, some through commercial sites, and some through a special program for the blind through the Library of Congress. I say all of that to say this. I was fortunate to grow up at a time where I became quite familiar with many different storage formats for audio recordings and what to do and what not to do to preserve them.

I didn’t start out to run a recording studio or to do restoration work of any kind. I was and still am a musician. Having recording equipment available was an easy way for me to compose music, as well as a convenient tool for studying and learning. I only really became interested in restoration work as I began the process of transferring my own analog tapes to digital. Over the years, I have found that well maintained analog playback equipment is becoming harder and harder to find. This is important for a couple of reasons. First an improperly maintained player can actually damage the record or tape being played on it. Second, without an understanding of how an original tape was recorded, and without the proper training how to set up and maintain a player, a digital transfer will be quite poor indeed.

One of the most important rules to follow when transferring audio to digital is to do no damage! It may be that better equipment will be available in the future. If the medium is destroyed now, then that higher quality transfer will never be possible.

I believe that to do any job well requires a bit of understanding of its history. If I was designing a car, it would be helpful if I understood how the design of cars has progressed over the last hundred years, so that I don’t make the same mistakes that others have made. In the case of restoring and transferring records and tapes, it is essential to understand how the record or tape was created in the first place.

As vinyl is making a comeback, most people are fairly familiar with records, either having them growing up as I did, or as a new fad. What most people might not know is that the groove on a record can have various shapes and sizes. Old 78s have one channel of sound, monaural or mono. The groove is wide and deep, with the audio information being at the bottom of the groove, and recorded vertically, meaning that the needle moves up and down to play it. The material used to press the records was designed to keep the needle sharp as the record is being played. Contrast this to the Edison record. They are recorded at 80 revolutions per minute, or rpm. Their groove is also fairly wide, but the recording was placed horizontally in the groove, meaning that the stylus moves back and forth sideways to play it. The stylus in an Edison player had to be replaced regularly, because the record itself didn’t keep it sharp. However, an Edison record makes a remarkably clean transfer, because the stylus isn’t playing a rough abrasive material. In 1949, the modern album and the 45 came along. They had a smaller groove and better sound quality. Because of better playback equipment, the records no longer needed to contain a way to keep the needle sharp. In the late ‘50s came stereo records. The shape of the groove changed slightly, and the sound was recorded on both sides of the groove rather than at the bottom. Because of the differently shaped groove, a mono stylus will damage a stereo record. Conversely, playing a mono record with a stereo stylus won’t damage the record, but it will result in reduced audio fidelity. For this reason, I have four different cartridges I use when transferring a record. I determine which is the closest to how it was originally recorded, and that one will usually give me the cleanest sound.

Reel and cassette tapes come with their own history and variations. Reel tapes most familiar to the general public are the ¼ inch variety. However, there are no less than four formats of recordings that can be found on ¼ inch tapes. Reel tapes can be recorded at several speeds, and this can be true for all of the different formats. The oldest format, introduced in 1948, was one channel of sound across the entire tape, or full track. By 1953, there were tape recorders that could have two monaural tracks of recording on one tape, each going in the opposite direction. In 1954, the first stereo recorders were introduced. They also had two tracks of audio, but they were recorded simultaneously and in the same direction. In 1959, the quarter track format was introduced. This allowed two stereo recordings to exist on one tape. As with the two track mono format, one simply turned the tape over to play the other two channels. To allow people to play previously recorded two track tapes, the tracks were interleaved, so track 1 would go forward, 2 would be backward, 3 forward, and 4 backward, so a player would play tracks 1 and 3.

In the ‘70s, recorders were made that could record and play all four tracks at once. Musicians loved them! They could now have a fairly inexpensive recording studio at home.

Cassettes originally were used for dictation, but over the years, their sound quality was improved. Most cassettes were either recorded in mono or stereo, with two sides.

As with paper or film, recording tape deteriorates over time. Some of the first reel tapes used paper for their backing. These tapes are extremely fragile! Fortunately, tape manufacturers abandoned this early on, so they are rare to find. I’ve only transferred two of those. For several years, tape was made using a backing of acetate, and more modern tapes use a Mylar backing. And in the 1970s, many of the higher priced tapes were back coated to improve their performance.

Now to the fun part! If someone brings me a reel of tape for me to transfer, the first steps I need to take are to figure out what kind of tape it is and what format was used to record it. If the tape has an acetate backing, it will break easily, whereas the Mylar backed tapes will stretch. If the tape is new enough to have a back coating, it is likely that it will be sticky. In extreme cases, the coating can be sticky enough to pull the oxide off of the next layer of tape, rendering the tape useless unless properly treated first. If the acetate backing becomes extremely brittle, it requires a totally different treatment. Most Mylar backed tape will play as is, but sometimes it can squeal while it is playing. This means that the lubricant that was present in the tape when it was new has dried out. If the tape has an acetate backing, it may curl, causing it to not make good contact with the play head. They can also squeal sometimes, but they require slightly different lubrication than the Mylar tapes. If a tape is sticky, the most common solution is to bake it. If an acetate tape is extremely brittle, it helps to freeze it. However, you don’t ever want to bake the acetate, because it will totally fall apart! All of this has to be sorted out before the tape is played, because irreparable damage may result otherwise. Oh, and just looking at the tape box may tell you nothing, because it’s really easy to put 1 tape in another’s box along the way. I know this, because I have done it with my own tapes! Once the tape is threaded, it can be played. Playing a tape on a machine with the wrong format of heads won’t damage the tape, but the sound may be very soft, or you may hear sound going forward and backward at the same time. If this happens, it’s time to change players to one with the proper head configuration.

When digitizing a tape, it is important to play a tape on the same head type as the machine that recorded it. Playing a full track tape with a two track stereo head results in more hiss and a boost in the low end. That might be all right for well recorded speech, but it is terrible for music.

The most common mistakes I’ve seen by inexperienced people are tapes played on the wrong player. To make matters worse, many institutions believed that once a recording was digitized, they no longer needed to keep the originals. I have CDs of poor tape transfers issued by major labels, but the original tapes were thrown away years ago, and a better transfer can no longer be made. Training comes in to play when a tape was recorded on a machine that was out of alignment. For the best playback, I need to misalign my player to match the recorder. I’ve had more than a few occasions where I transferred a tape after someone had tried to do it themselves. When they weren’t satisfied with what they got, I would have a go at it. In some cases, I found material on the tape that my client thought was missing. In all of these cases, they have remarked how much more clear and how quiet the sound was. I have also heard digital recordings where proper alignment was not done, and when I offered to help do it again, I was told that the originals were gone.

Transfers of Cassette tapes can sound better if these same ideas are kept in mind. If a Cassette was recorded on a monaural recorder, it’s best to play it on one as well. This is because of the large space or guard band between the two stereo tracks. Usually the noise level will decrease significantly with the right player. Aligning the play head also can make the transfer brighter and quieter as well.

Not all digital files are created equal. One mistake I have seen along the way is transfers made directly to MP3 or M4A files rather than WAV or AIF files. This is because MP3, M4A and some other file formats are compressed. They take up less storage space, but around 90% of the data needed to accurately construct the audio is thrown away in the compression process. Being that I work in the PC world rather than on a Mac computer, I always make my transfers into WAV files. Afterward, I can always compress them if the client needs the files that way.

If all of that isn’t enough of a puzzle to put together, there is the material on the tape itself. Sometimes it is possible to determine whether the tape is an original or a copy. If the original exists, it will likely make a cleaner transfer to digital.

In 2015, I transferred close to 90 radio broadcasts of Dr. Ernest Holmes for the Science Of Mind Archive. While these tapes were well maintained, they weren’t the originals. The originals were recorded on records. I could hear the turntable spinning up and pops on many of the reels. It was determined that the archives had no such records, and that the tapes were high enough quality to work with. Some of the talks were exact duplicates. Those were easy to find. At the end of each broadcast, the announcer would say what the next week’s talk would be. Usually they would line up with the dates  on the boxes, but sometimes, the announcements and the dates just didn’t line up. What a great puzzle! By using the dates we knew to be true, and with the help of the tags about the next week’s topic, we could put a more accurate date line together.

In 2005, a client brought me some reels of tape he had recorded in Ireland in the 1960s. They all sounded fast to me. Anyone talking sounded like they were breathing Helium! Then I noticed the soft 60 HZ hum in the background. I called him up and asked him if he was sure these were the originals. He was certain they were, so that got me thinking. If I slowed the hum down so that it was at 50 HZ, the voices would sound more natural, and voila! When he picked them up a few days later, I played part of one for him. He said, “They sound normal! When I’ve played them, they always sounded fast.” I asked him how he recorded them, and he told me, “I took my recorder over there. The tapes sounded great over there, but they always sounded wrong when I got back. I never could figure out what happened.”

I explained that the motor in his machine maintained its speed by using the frequency of the power grid, as an electric clock does to keep perfect time. Ireland’s power is at 50 HZ, while ours is at 60 HZ, making the recorder run 1/6 faster here. He gave me a very nice tip for solving his mystery.

Did you know that some of the railroads and electric public transportation used a frequency of 48 HZ for their power? This is how the frame rate of 24 frames per second became standard in the film industry. In the early days of electricity, California adopted this standard for their power grid. In the late 1940s, they changed to 50 HZ power, as is common in Europe. Around 1949, they changed again to the 60 HZ standard that we use today in the United States. Another client brought me a record of a radio broadcast that seemed strange to me until I did some research. If I made the instruments be in tune, the hum in the background was at the wrong frequency. If I put the hum at 50 HZ, it was close, but the instruments were still out of tune to A 440. I settled for making the instruments in tune. That night though, I did a lot of reading about power grids. My client thought that the record had been made in the early ‘50s, but my research showed that it was likely a few years older than that, because the power grid was running at 48 HZ when the record had been made.

I’ve always loved a good puzzle! Through the years of digitizing various recordings, there are times I get the wonderful opportunity of putting puzzles back together.

Park Peter’s Background:

Park (along with Karen Karsh) was recently featured in the June 2018 issue of Science of Mind Magazine in a beautiful article written by Kent Rautenstraus entitled, “Exploring What Eyes Cannot See”. 

Audio Park Recording Studio LLC has been in business in Colorado since June of 1990. However its primary owner Park Peters has been in business since 1978. He began working with digital recording in 1985. In 1992, Audio Park Recording was one of the first studios in the Denver area to have the capability for full digital editing and mastering. Mr. Peters moved to his current location in Arvada Colorado in January of 2015. Mr. Peters is an expert in the restoration and transfer of reel tapes, records, wire, dats (digital audio tapes), and cassettes. He has restored and digitally recorded Edison cylinders from as early as 1902 for several clients including two museums in Colorado. Over the last five years, he has been restoring and transferring the audio archives for the National Forest Service office in Colorado, which included reel tapes, cassettes, and 16 inch radio transcription disks from the late 1940s. He has had clients come to him for digital transferring and mastering from as far away as Japan, Africa, Canada, and England. He has performed transfers from both 2 track and multi track master tapes for Sony, Columbia of Japan, and Capree records. He has worked as an independent contractor to create and oversee the conversion of material to be used in web sites for corporate training for Lionbridge Technology, Swizzle, Xerox, and INTL. Over the years, he has also transferred and enhanced cassettes, microcassettes, and digital recordings for attorneys and law enforcement agencies throughout the state.

Park can be contacted at