Posts Tagged ‘Vinyl’

Playing Warped Records

Sunday, May 23rd, 2010

Records of various materials are sent to us  in different conditions. Some records arrive with cracks across the surface, some with pieces missing from the outer edge, and some arrive warped. Vinyl warps quite easily if is left exposed near a sunny window or left in a car on a hot sunny day. Take care where you store your vinyl and remember if your turntable is near a window replace the record into its dust cover and sleeve after playing and don’t leave the record exposed to sunlight on the turntable.

A customer recently sent me a large crate of LPs to be restored and transferred to CD. One box set, Bach’s Brandenburg concertos, had obviously suffered a fate with sunlight as both LPs were warped along one side of each record.

The first picture here shows the damage (click on the picture for a more detailed view). Playing a warped record in this condition is virtually impossible because at 33 1/3 rpm the forces exerted when the arm suddenly drops and then rises (or on the reverse side of the record, rises and then drops suddenly) throws the stylus out of the groove  - not good for the record or the stylus. One method in overcoming this problem is to reheat the vinyl while it is sandwiched between two pieces of glass and this is a reasonably successful method of flattening the record. However a method I favour more is based on reducing those forces of movement and simply reducing the speed of the turntable by half – in this case to 16 2/3 rpm,  then recording the material onto a tape machine, we use a Studer A810 and run it at 15ips. This obviously is a lengthy process, all the material takes twice as long as usual to record but the results are well worthwhile.

Once the material has been transferred onto tape, the tape machine can then be speeded up to 30ips doubling the speed and returning the material to it’s rightful speed.

The choice of turntable for carrying out this type of rescue mission is quite critical, we use a high quality deck djs would use in  discos or clubs. The Stanton STR8.150 is ideal because this deck was designed with a short straight arm allowing the dj to efficiently carry out “scratching”  (manually moving the record forwards and backwards), many standard decks (including some dj decks) cannot handle these sudden forces and, again, the stylus will jump hence the specific design of the Stanton. Therefore this is an ideal deck for playing warped records with the associated forces exerted on the stylus and arm even at slower speeds.

Warped record on deck

Warped record on deck

Studer A810

Studer A810

Stanton STR8 150

Stanton STR8 150

Record Cleaning – Vinyl

Friday, February 5th, 2010

I was brought up in the understanding that the least human contact a record has the better it would perform and the longer it would last, Therefore I have always had a healthy respect for this media and never touched the surface of a record unless absolutely necessary and as technology developed over the decades I adopted the same policy with CDs, Mini Disks and where possible magnetic tape. I still think it is a good policy but in the real world records do get marked, they do get dusty and they do need cleaning just like everything else in life. So today I want to look at two ends of the spectrum in record cleaning. That means the expensive way and the economic way.

For professionals and record enthusiasts we have a selection of efficient machines available, two made by VPI, the HW165 and the HW15 and by Moth the RCM MkII. These machines operate with two phases, firstly by working a degreasing agent deep into the groove of a record, breaking down oil and grease which would attract a build up of dust and detritus giving rise to surface noise, swishes, clicks and ticks. The second phase is a drying process. The units operate at slow speed with a bi-directional motion allowing the degreasing agent to be pumped into the groove attacking the dirt from both directions and then vacuumed away.

VPIHW16

VPIHW16

Record with finger prints and debris

Record with finger prints and debris

The  picture here shows a vinyl record where an attempt had been made to clean it with a detergent and tap water. As you can see this approach leaves its own film which creates even more surface noise. Click on the photos for a more detailed view

A cheaper solution involves shopping not in your local Hi Fi store but at your nearby garage and purchasing a container of concentrated car screen wash and a container of distilled water. Mix one part screen wash with three parts distilled water and with a soft cloth, which will not shed particles, apply the mixed solution to the groove of the record following the line of the groove. Do this in both directions using plenty of the solution. Then rinse the record at a sink with the distilled water removing all the solution and debris. With another soft dry cloth wipe off the residue from the vinyl and let the record stand to air dry perhaps for 10 – 12 hours (do not play the record while it is wet) an empty dishwasher or plate stand is ideal for this. Never use tap water or washing up detergents as these will leave a film and cause surface noise.

Distilled Water and Screen Wash

Distilled Water and Screen Wash

Applying the Solution to the record with a soft cloth

Applying the Solution to the record with a soft cloth

Rinse off the solution with distilled water

Rinse off the solution with distilled water

This latter cleaning method is ideal if you are a club dj where the nature of the job involves handling the surface of the record, a trip to your nearby garage will breathe new life into the vinyl and save you over £500 by not having to buy the VPI or the Moth machines!

Use another clothe to dry the record

Use another clothe to dry the record

Leave the record to air dry for about 12 hours

Leave the record to air dry for about 12 hours

Disc Cutting

Sunday, December 6th, 2009

The black art of disc cutting has always intrigued me and I always had great admiration for my colleagues in Decca who had mastered this skill and demonstrated it with precision.

Pre 1950 virtually all recorded material was cut directly to wax discs. Radio stations used 16” transcription discs which operated at 33.3rpm and had capacity for 15 minutes of material on each side. While at Decca I had the privilege of transferring the entire collection of Bing Crosby’s radio recordings from such discs. These programmes had been sponsored by Kraft, Chesterfield Cigarettes and Philco Radio and had been broadcast in America throughout the 1940s and 50s. However, due to problems with copyright, we were unable to release any of the restored material at the time which was unfortunate because the shows included a host of top names of that era, Al Jolson, Anne Shelton, Bob Hope, Andrew Sisters to name just a few.

Once magnetic tape was adopted in recording and radio studios around the world the need to cut direct to disc was soon abandoned. All recordings were made to tape with the advantage of editing, re-recording, multi-tracking and greater versatility.

The disc cutter came into his own when the finished master tapes were passed to him for transfer to disc. Developments in the 1950s meant that wax discs were replaced by lacquer-coated metal blanks. The lacquer was a cellulose nitrate coating soft enough to be easily engraved by the cutter yet hard enough to permit a number of direct plays. This ruggedness meant that during the cutting operation the engineer could monitor the quality of the cut by switching between the signal applied to the disc and the audio actually cut onto the disc. The picture below shows Decca disc cutting engineer Harry Fisher using a Neumann cutting lathe to produce a master lacquer disc. Harry had a great fondness for music from the 1940s and 50s and was therefore always assigned the tasks of cutting the material I worked on. Every cutting engineer would leave his insignia in the run out groove of the discs they cut, we termed it the “dash number” Harry’s was always W, Trevor Fletcher, who cut all the Decca singles was C. Their insignia was always preceded by the lacquer reference number. For example if a disc was the first cut from the master tape the dash number would be -1W. Sometimes the master discs were damaged in the processing operation at the pressing plant. A second or third disc would then need to be cut; these would be -2W or -3W and so on.

Decca Disc Cutting Room

Decca Disc Cutting Room

In the photo you can see Harry inspecting the quality of the groove using a x40 microscope. To the right of the picture (just out of shot) is a rack carrying the high powered amplifiers necessary to energise the cutting styli. These amplifiers were generally operating in the order of 600w per channel, this amount of power generated heat on the coil cutting head of 200 degrees Celsius. This was cooled using helium gas. The stylus itself was heated which allowed a smooth cut in the lacquer therefore reducing surface noise.

Other points of interest in this photo: firstly the Decca made console in the middle of the shot. Every cutting room and tape duplication room had a similar sized console with standard equipment; Decca designed and made equalization units, limiters, test tone generator, quadrant faders and remote control switching units. Also seen in this shot is the triangular shaped meter panel. All monitoring at Decca was performed with PPM meters working to a reference point of + 4dBm, peak recording level was usually +8dBm. For comparison purposes a pair of VU meters were also on this panel. On the rear of the console you can see the patch field. To the left of the console and built into a white cabinet is a Garrard 301 turntable for the playback and quality check of new pressings as seen on the table. Outside of the shot is a Philips Pro’ 51 tape machine. These machines were standard in most of the rooms by the early 1970s. The Pro’ 51s used in these cutting rooms were especially modified by our engineers to include an extra playback head. This head was situated before the main bank of heads and allowed an early audio signal to be sent to the lathe for groove adjustment depending on modulation variations.

My grateful thanks to Wes Stillwagon who administers the excellent Mantovani web site: www.hallowquest.com/ and who kindly allowed me to reproduce this photograph.

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.

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”…

The Beatles

Monday, September 14th, 2009

All in one week Vera Lynn entered the top 10 (today she’s at number 1) and at the same time the Beatles remastered albums were released. This new presentation means that all of the Beatles tracks are now available in stereo but with the collector and connoisseur in mind, a box set is available in mono. These new Beatles releases have taken four years to digitally remaster with a team of Abbey Road engineers working with state of the art, as well as vintage, equipment. Forty plus years ago the principle tape machines would have been the British made BTR2 and BTR3. Built like battle ships and weighing a ton these were the size of an Aga cooker but were the work horses of many recording studios in the1950s and 60s. What is obvious in listening again to these incredible recordings is not only the Beatles musical creativity but the technological achievements made by Producer George Martin and engineers such as Geoff Emerick, Norman Smith, Richard Lush and others. Even when the Studer 4 track tape machine was used to record the Sgt Pepper album, still the technological bounds were being pushed. Geoff Emerick would record drums in mono on track1, bass, guitars and keys on track 2, vocals on track 3 and overduds on track 4. If more tracks were required these tracks would be sub mixed to a second Studer. Tape loops, reverb, flanging and other effects all taken for granted in today’s software generation but were very much all in their infancy in the recording industry of the 1960s.

Perfecting Sound Forever

Wednesday, September 2nd, 2009

I have just started reading Perfecting Sound Forever by Greg Milner. Greg explains Edison’s development of the phonograph from the early days of the cylindrical waxed paper and the first ever recording – “Mary had a little lamb”. There then followed 38 years before his invention was publicly demonstrated to a packed hall in Montclair. Great artists of the day were  present in that hall. The invite was to witness “a comparsion of live music and its reproduced facsimile”.  The evening was a facinating demonstation where artists such as Christine Miller and Arthur Walsh, would sing and play live only to stop suddenly and allow their recordings to continue the performance!  Greg writes “there were audible gasps from the audience”.