Posts Tagged ‘Tapes’

More About Cassettes

Wednesday, February 2nd, 2011

Back in the late 1980’s, long before the days of Pro-Tools and Cubase multi-track recording, manufactures were trying to squeeze every possible ounce of usefulness out of existing analogue technology. Professional multi-track tape recording had been around for a number of years, most famously the 4-track recordings of the Beatles Sgt Pepper album at Abbey Road studios in the mid 1960s.

By the early 1970s 8 and 16 track machines were common place in most recording studios, in Decca’s West Hampstead studios, studio 2 (mostly used for groups and small bands) was equipped with a Scully 8 track machine, and after it’s refurbishment in 1973, the giant studio 3 (mainly used for large orchestras) was equipped with a 3M 16-track machine. In the 1980’s manufacturers for the domestic market, home studios and demo recordists produced various types of 4 track tape machines and ultimately 8 track too.

Tascam 238S

Tascam 238S

Some were reel to reel machines but most were based around the Philips Compact Cassette format.

The machine shown here was made by Tascam – the 238S – and was manufactured around 1988. The fact that the deck was  made for a cassette meant this was cheap to run and gave very good results. The deck ran at 3¾ inches per second, and would use high bias type II tapes. The heads were aligned to interleave the 8 tracks with even tracks grouped together and odd tracks grouped together this meant that the full width of the tape was used allowing only one pass of the tape – there was no side 2. The deck incorporated Dolby S that provided 10dB of noise reduction at low frequencies and 24dB of noise reduction at high frequencies. These combinations of good quality tapes, a faster tape speed and Dolby S gave some very good recordings. Added to its impressive pedigree was dbx, which was a wide band compression-expansion system that provided a net noise reduction system (dealing with broadband noise not just tape hiss). In effect the dbx system could give a 90 dB dynamic range very impressive for a small cassette. This one seen here in our studio has seen plenty of active service and in its lifetime I have used it to record many choirs, bands and a variety of singers. In my opinion this was the ultimate machine for squeezing the best out of the humble cassette.

The 1990s then saw the production of many digital tape machines, Tascam famous for the DA-88 in 1992 supported 16 bit/48kHz format recording onto Hi8 tapes. This technology has come along was with Tascam’s latest machine, the DR-680, offering 24 track capacity at 96kHz/24 bit recording onto an SD card.

Cassettes

Friday, October 8th, 2010

Cassette tapes were deemed to be a great step forward in the development of tape recording and recorded sound back in the 1960’s. Cassette machines were portable, tapes were easy to snap into the tape transport compartment and by the end of the 1960s Musicassettes were available which meant we could enjoy our favourite artists indoors, outdoors and in the car. As you’ve read below the Philips Cassette was a stage on from the Philips/Norelco dictation machine but the differences were the physical size – the new cassette was a third the size of the Philips/Norelco cartridge, the tape – the Cassette tape was 1/8 inch wide compared to 1/4 inch wide standard thickness tape on the early machine and the cassette was aimed at the mass market rather than be restricted to dictation and office use.

However its limitations were obvious, the slow speed (1 7/8ips) meant a restricted frequency range and a poor signal to noise ratio. The tape itself was thin leading to easy tape damage particularly with the longer tapes. BASF introduced extra mechanics in their 120 minute tape cases to prevent tape damage and improve wow and flutter figures. Commercially produced cassettes of albums were available alongside traditional vinyl records but early cassettes proved to be rather poor in quality compared to their vinyl equivalent. However regardless of these disadvantages the cassette became very popular and is still in use in a number of homes, churches and schools.

As the cassette gained popularity, so electronic manufacturers invested heavily in developing better decks and improved ways of recording and reproducing the signal at this slow speed. Enter the Dolby system which was beginning to make huge inroads in recording studios with Dolby A.

To cater for this new market Dr. Dolby’s labs introduced Dolby B for the domestic market with a specification of reducing tape hiss by 10dB. This was followed by Dolby C and S during the 1970s and 80s . Other manufacturers produced their own noise reduction systems all with a view to squeezing as much quality as possible out of this very humble format. Alongside these developments magnetic tape producers introduced high quality tape purely for the cassette market and so chromium oxide and metal tape cassettes became available allowing recordists excellent media for producing very high quality recordings.

Damaged Cassette Tape

Damaged Cassette Tape

Here is a good example of a damaged cassette recently sent to us.

Like all material sent to Lost Sounds this tape was very valuable to its owners and contained some cherished recordings from the 1960s, unfortunately a hungry tape deck decided to chew up the tape.

The owner could not open the tape compartment door resulting in them prising the cassette out with the resulting damage you can see here. Some of the damaged tape had to be edited out and the remaining spools installed into new casing.

The entire recording was then transferred to CD with the audio restored and greatly improved to be enjoyed and saved for the future .

Cassettes

Cassettes

Another aspect of our work with cassettes can be seen here. This is a customers entire cassette collection of 180 C90 tapes. These tapes contained recordings from the 1980s through to the early 1990s. The request was to convert the entire collection to MP3 format and store on an external hard drive.

This is a time consuming exercise, the work has to be carried out in real time and if you do the maths you will realise there are many weeks of work here! In order to accomplish lengthy work like this we use a second studio freeing up our main studio equipment so other work can continue.

During the 1980s the cassette gave way to the up and coming Compact Disc so many precious recordings were stored away on this old format, today we are privileged to restore and transfer a wide range of recordings from baby’s first words to church and school concerts enabling families and friends to continue enjoying these lost sounds.

Early Philips/Norelco Dictation Machine

Saturday, January 2nd, 2010

For those interested in old magnetic tape recording formats, the photos below show a 1960s tape cartridge recently sent to us for restoration and transfer. The cartridge would have originally been used in the Philips/Norelco dictation machine shown in the third photo. This cartridge concept would have been attractive for office staff because it eliminated the need to lace the tape. At the end of side one the cartridge could easily be flipped over to record or replay the second track. This innovation was the forerunner to the Philips Compact Cassette introduced in the mid 1960s with dictation and speech recording in mind, however by the 1970s the humble Compact Cassette had been widely adopted for music recording which attracted further development; low noise tape, better frequency response, Dolby B and some very advanced decks to record and play the cassettes on.

We found this elderly cartridge played at 1 7/8ips and was recorded on both sides. Towards the end of the first side the recorded material speeded up quite considerably probably indicating a worn or slack belt on the take up spool of the original machine – we were able to correct this speed fluctuation and present our customers with a CD of their father speaking onto the tape in 1962.

Both the cartridge and original box were in good mechanical order as can be seen from the photos.

My thanks to David Morton who allowed me to use his photo of the Philips/Norelco machine (www.recording-history.org).

Philips/Norelco Dictation Cartridge

Philips/Norelco Dictation Cartridge

Philips/Norelco Dictation Cartridge Box

Philips/Norelco Dictation Cartridge Box

Philips-EL3581-00

Philips-EL3581-00

Grundig Dictation Tapes

Saturday, November 14th, 2009

It never ceases to amaze us at Lost Sounds the abundance of recorded material stored away in homes up and down the country. Much family history along with the voices of relatives’ recorded decades ago, some now deceased, are treasured heirlooms as precious as old photographs, films and diaries.

One such recording, made in 1957, arrived in our office recently. The recording had been made on an early Grundig Dictation cartridge. Apart from a small sequence of dictation on the tape, the recording was mainly of family gatherings; playing games, singing and piano playing – what memories.

The earliest dictation machine using magnetic tape, produced by Grundig, was the Stenorette A made in 1954. This was also about the time Dr Max Grundig  moved his operation into a state of the art factory at Bayreuth and dubbed it the “largest tape recorder factory in the world”. Certainly Grundig led the world in dictation machines which were gaining popularity in offices everywhere – technology was creeping into the work place. The tape recorders themselves, not the most attractive of devices, were quickly nicknamed the “Green Frogs” and had a tape running time of 30 minutes.

The Stenorette A was followed by the more superior Stenorette R and  the Stenorette SL both around 1955.

The first picture shows the original cartridge we received. The cover sits over an open reel of quarter inch tape – and needs to be handled with great care. The second picture shows the cartridge open. The spindle hole is standard only to Grundig Stenorette machines therefore to play this tape meant transferring it to a standard 5 inch spool. In the third picture you can see how versatile a screwdriver is! It makes a perfect spindle as the tape is transferred on the Revox B77 tape machine. Finally from the Revox onto the Sony tape machine which can play back at 1 7/8 ips. The quality of this 52 year old tape was remarkably good, however there was a certain amount of hum which we were able to filter out.

Dictaphone cartridge

Grundig Cartridge

Cartridge opened

Cartridge opened

Spooling from cartridge to standard spool

Spooling from cartridge to standard spool

Dictaphone Tape playing at 1 7/8ipsTape playing at 1 7/8ips

Early Audio Restoration

Monday, October 26th, 2009

There seems to be great interest in the Decca Record Company and some readers have asked me write more about early equipment used in Decca to restore old recordings.

Up until 1971, the transfer and restoration of Decca’s 78’s was carried out in Reduction Room 1 at the West Hampstead Studios (Broadhurst Gardens). When this room was not being used for the balancing of 8 track recordings and mixing down to produce stereo master tapes; the room was given over to re-mastering archive material. The additional equipment installed in this room (better known as Pull-Off Room 1) for the transfer of these old recordings was a Garrard 301 turntable, Pultec equaliser units and a Pultec high and low pass filter.

During that year, the demand for more compilations of nostalgic material was rising fast. Decca had an enormous catalogue of recorded material going back many decades and the country was waking up to the talent of artists of yesteryear. The only way forward was to create a purpose built room with up to date equipment – a room that was devoted to restoring 78’s and early magnetic tape recordings. It was decided to create this room not within the recording studios complex at Broadhurst Gardens but in Decca House on the Albert Embankment.

As the engineer appointed and trained to operate this new room I initially worked alongside R&D engineer Bob Goodman and his team, designing the console and piecing together the equipment and spares I would need at Decca House.  The guys at the studios made a superb console with a Dexion frame and wooden panels. The console incorporated a Neve mixer, Astronic and Pultec equilisers, a Klark Technik graphic equiliser and a Pultec high and low pass filter.  By December 1971, the new room was complete with console, Lancaster speakers, Scully 280 and Revox A77 tape decks and EMT reverb plates. I later acquired an ancient BTR2 deck for the playback of tapes at 30ips and modified it to operate remotely from the console. The original Garrard 301 also came to Decca House. This deck had two arms one carrying an Ortofon cartridge, the second a Shure cartridge. The Shure had multiple styli of varying sizes which were essential in extracting the best sound from the records. We also had a second 301 which we used for the transfer of vinyl recordings at 33 and 45rpm. This deck carried a Decca cartridge.

Throughout the 1970’s this was the top of the range equipment used to transfer and restore old recordings. But it was not until the early 1980s when the British Library National Sound Archive recognised the need to preserve its vast store of recorded material; that led to them funding a research programme at Cambridge University to develop computer based programmes capable of restoring vintage recordings stored on ageing media. The first prototype was announced in 1987 – the CEDAR Computer. Later to become a company in its own right, Cedar now have well over 20 years of experience and success in the audio restoration and forensic markets around the world. Having restored old recorded material the hard way I can appreciate the ability and sophistication of Cedar equipment and it is a vital tool. At Lost Sounds our Cedar units are workhorses that are integral elements in cleaning up customers’ recordings without harming the required audio signal. These units are powerful tools that allow us to work in real time adjusting parameters as the signal is being processed to achieve optimum results.

Clicks, Ticks and Audio Tape – Part 2

Monday, October 19th, 2009

When faced with any new audio restoration task our golden rule in Decca was, if possible, always use the original recording, second best would be a choice of “takes” which could be pieced together to give the best quality. We were fortunate in that much of the material we worked with was either from original matrix discs (stampers) kept at our record factory in New Malden or were from the dark end of our tape library known as the “graveyard”.  From the 78 rpm matrix discs new pressings were specially processed for us onto vinyl however despite this many of these matrix discs had deteriorated over the decades and presented their own problems that needed solving as mentioned earlier regarding the Vera Lynn pressing. Some material was no longer available to us because of the passage of time (I understand part of the New Malden complex was destroyed by a bomb during the second world war and much material lost) in these instances we approached private collectors, often the BBC record library and borrowed commercial shellac pressings. Of course when faced with shellac the material is prone to severe deterioration over time and this causes multiple clicks and crackle as was the case with the Boswell Sisters mentioned earlier. Shellac is a very brittle material and often rare records came to us damaged with pieces missing from the outer edges. These were great challenges because it meant creating a new intro. By editing in passages from elsewhere in the record we could re-create the introduction often unbeknown to the listeners.

The restoration of this material was very much a manual process in those days and therefore very time consuming. The thought of efficient and effective devices for removing these clicks, crackle and background noise were just dreams that would not materialise fully until the digital age, fast processors and effective algorithms.

Initial attempts at an electronic declicker gave birth to a device known as a switcher which relied on two identical mono signals (such as a mono record signal being fed to a stereo cartridge), the individual signals from the two walls of the groove were simultaneously fed to the switcher which was constantly hunting for the cleanest of the two signals to switch to. In reality only loud clicks were processed with any real success, the system was incapable of differentiating between wanted material and unwanted low level ticks. Later developments then saw a digital device available called Sample and Hold. This was a step on from the early attenuator device mentioned last week. It still introduced a drop out but at constant amplitude to the last wanted signal. The drawback here was unpleasant noises that resulted from this process such as low frequency thumps, ticks and even distortion in places. Following this a more sophisticated device was  introduced utilising a system called Linear Interpolation, which followed the same concept as Sample and Hold however this development allowed the process to match signal amplitudes before and after the click or tick.  Linear Interpolation has developed now to a point where the algorithm incorporates what is known as signal modelling. This process analyses the signal over a period of time learns the “model” of the wanted signal, removes the offending click or tick and replaces the unwanted noise with a shaped waveform that fits the model of the wanted signal. This latter tool is highly sophisticated and one that Cedar equipment and software executes perfectly. Recently I was working on a rare Jazz recording for a customer, when played straight from disc the recording was tarnished with multiple clicks and, more annoyingly plenty of ticks. I demonstrated the power of the Cedar algorithms to a visitor who happened to be in the studio at the time, by switching between the A and then the B signal (A pre processing and B post processing) my visitor was astounded by the resulting quality – more about Cedar next time.

Clicks, Ticks and Audio Tape – Part 1

Thursday, October 8th, 2009

Removing clicks and ticks from recordings has come a long way in the last 20 years. Digital techniques, along with modern software and advanced algorithms, are a far cry from the manual process we used to suffer! As a young recording engineer in the 1970s part of my training involved working alongside one of Decca’s finest classical music recording engineers, Jack Law. Jack had recorded many of the best orchestras, operas and concerts and spent much of his time recording in Vienna. It was Jack who taught me the skilled art of tape editing while following the score, along with the practice he knew I was destined for – declicking! We used a Studer A10 tape machine for the training exercise and simulated the clicks by disconnecting the record amps and reconnecting them – worked a treat. Over the years I have edited out thousands of clicks and ticks from shellac and vinyl records. Readers may be interested to know that even some new material from the States was issued in Britain having been dubbed from discs. The early release of the Righteous Brothers “You’ve Lost That Loving Feeling” was issued this way because the tape hadn’t arrived from Decca in New York. I also remember dubbing a complete Chi-Lites album to tape for the same reason. Having copied a disc onto tape, this ancient method of declicking involved lining the tape up so that any click was precisely on the replay head, spooling by hand from left to right you could be spot on. A chinagraph line was then marked on the back of the tape, but only on the top half  (if the piece had to go back in you knew which was top and which was bottom). About 2-3 mm of tape was removed and the tape spliced back together. With the tape running at 15 ips (38.1cm per second) removing this small piece of tape amounted to approximately 8 milliseconds of recorded material – the size would vary depending on the intensity of the click, tick or thump. I always edited at 45 degrees and never vertically as this latter method could introduce further unwanted thumps. Most of the time the edit would work without any affect on the recorded material; however it did depend upon the type of material. I remember having great trouble with Gracie Fields singing Ava Maria – those long sustained notes don’t lend themselves to having clicks removed from them! On another occasion we were putting together a new album of the singing trio, the Boswell Sisters. The album was virtually complete and then Geoff, the Producer, was able to borrow a rare 78rpm shellac single with the group singing “I Found A Million Dollar Baby” (E 36826 recorded 25th May 1931) and “Sing A Little Jingle” (E36825 also recorded 25th May 1931). The disc was in very bad condition with clicks throughout. I removed about 400 clicks from each side which took me the best part of a week to complete. With the album finished it was issued in 1975 as Sweet Harmony – Hot Rhythm on the Decca Vocalion label (VLP 5). I kept all the clicks and still have them to this day.

A friend of Geoff’s, a musician and keen restorer of recorded music himself designed and built a devise which would clamp the tape down, and instead of editing out the click, this devise had a scraping mechanism. A needle point would scrape the oxide from off the plastic backing tape producing a small dropout. I never heard any of the results from using this procedure but Geoff Milne was very impressed with it. The concept is not unlike early electronic declickers which could detect a click and immediately mute the signal. What actually happened was the high energy of the click would initiate a very sharp fade out, mute and then a fade in. This fading/muting process would be only a few milliseconds and although it succeeded in making loud clicks less obtrusive, it failed to retain and restore the wanted signal. That was still some years away.

8 Track

Friday, October 2nd, 2009

As many have gathered, I am a great lover of old recording formats and have owned various tape recorders and record players since I was a small boy. One of these, quite underestimated I believe, is the 8 track stereo format. Originally designed in 1952 by American Bernard Cousino as a 4 track looped playback machine and running at 3¾ ips with 1/4  inch tape its great advantage was its ease of operation. Owners of reel to reel machines were hampered by having to thread each tape. The cartridge development eliminated this process allowing lay users to plug a cartridge into the slot and with an endless tape it could run and run. This idea was then developed by George Eash who refined Cousino’s design and produced a product in 1954 called the Fidelipac. First shown at the NAB (National Association of Broadcasters) exhibition at the end of the 1950s its potential was soon noted and was embraced by many radio stations and used extensively for the playback of jingles and commercials. Standard speed on this machine was 7½ ips giving superior quality and the fact it has survived nearly 50 years in virtually every radio station in the world is testament to its design and ease of operation.

The first commercial 8 track cartridge was available in 1964, following extensive development of the original Cousino 4 track design. Changes focused on the mechanics inside the cartridge introducing a pinch wheel and eliminating tensioning devises. The aim was to mass produce an efficient, easy to use product that still utilised ¼ inch tape which could be pulled from the centre of the cartridge spool purely by the capstan and pinch wheel, pass the replay head and returned to the outer circumference of the reel. The playback machines had refined stereo heads fine enough to allow 8 tracks (4 stereo programmes) which would physically move up or down the tape height depending on which programme was being played.  Programme switching was initiated by a small piece of metal tape which made the joint in the tape loop. Initial commercial interest was aimed at the car industry, but later in the 1960s and 70s playback machines were made for the home. Cartridges were mass produced alongside Music-Cassettes throughout the 1970s and 80s only to diminish as the CD gained popularity but were a major contributor to in-car entertainment.

At Decca we had a purpose equipped room for producing 8 track master tapes. These were recorded on a 1 inch Scully tape machine before being sent to the New Malden factory for mass production. One major problem in producing these 1 inch master tapes was timing. LP’s and cassettes only had two sides, cartridges virtually had four. The headache was trying to arrange the artists’ material into four neat programme lengths that were all more or less equal. The only way we could mark the length of each programme was to stick a piece of splicing tape onto the appropriate point on the master tape – what fun. Those of you who have listened to an 8 track would have witnessed the occasional fade out and fade in where timing was impossible. One of my son’s has recently given me over twenty ancient cartridges, everything from the Rolling Stones to Saturday Night Fever. Playing them back in the studio here I’m amazed at the quality of the cartridge format and playing at 3¾ips they had an advantage over the cassette which ran at half the speed, the cartridge therefore giving less tape hiss, a better signal to noise ratio and a good frequency response.

Analogue v Digital

Friday, September 25th, 2009

For years now the debate has been raging over the difference in sound quality between a vinyl record and a CD – one analogue, the other digital (16 bit/44.1kHz). Many mastering engineers and record producers take the debate so seriously that even though they are working in the digital domain, they include, in the final mix down chain, an analogue tape machine running at either 15 ips or 30 ips to give their mix that magic analogue “warm sound”. French hip-hop artist Wax Tailor who’s latest release “In the Mood for Life” has addressed the problem by producing his material on a disc which is a CD on one side and vinyl the other so fans can have the best of both worlds! What amazes me these days is that I have spent years taking clicks and crackle out of worn records; I have a studio stacked with expensive equipment and software specifically for improving the sound quality of old records and then I hear a new release on the radio or TV, where the producer has added some artificial clicks and crackle to give the material that “vinyl sound” – strange world

Ampex

Thursday, September 17th, 2009

During the Second World War, German engineers and scientists devoted much time, effort and money into developing the tape recorder. Following the war US Army Signal Corp assigned engineer Jack Mullin to study German electronics and how they had developed ideas and technology during the 1939-45 conflict. Within months Mullin was able to ship back to the USA two German Magnetophon tape recorders.  Following this Ampex Electric and Manufacturing Company was formed by Alexander M. Poniatoff in San Carlos, California. The name AMPEX consists of Poniatoff’s initials, with “EX” for “excellent” to form the unique name. Amazingly it was then the singer Bing Crosby who saw the potential of the tape recorder not only for his radio work (at the time Bing had a weekly half hour show on a national network) but for recording his singing in the recording studio. Ampex produced the first professional machines in the late1940’s called the Ampex 200 which quickly went into service in radio and recording studios around the country. Bing Crosby gave one of these machines to guitarist Les Paul who, not content to simply record straight onto it saw its potential. With two machines he could run them in parallel and copy from one to the other. Apparently on one occasion, Paul using this technique created 12 overlaid vocals of Mary Ford singing How High the Moon. During the early 1950s Ampex, and many recording engineers, could see that by stacking record and playback heads a large number of tracks could be recorded simultaneously and mixed individually; and so started the multi-track revolution. By 1954 Ampex produced the first multi-track tape machine which over the decades would develop from the humble 4 tracks to as many as 48 tracks in the1980’s. Back in 1954 at the Sun Studios in Memphis, equipped with an Ampex 521 reel to reel tape machine, an unknown truck driver named Elvis Presley recorded his historic first single, “That’s All Right”…