Today Poussin (artist name) welcomes us in his studio to present us the different parts of his work as a sound engineer in his different activities such as mixing, Dolby Atmos Mix, Mastering and Audio Preservation.
Poussin’s Digital Encoding System Studio exists since 2000 and is specialized in :
- the digitization of tape preservation, more than 20,000 tapes have been digitized
- multichannel concert mixing with more than 400 concerts mixed, from 5.1 to Dolby Atmos, for DVD, bluray and cinema.
- Multichannel music mixing since the beginning on SACD, DVD, Bluray, cinema
- Mixing and mastering in stereo, digital or analog
- The expertise of formats since Dolby Digital and DTS, then Dolby TrueHD and DTS HDMA, and also Atmos and SACD for a few years.
This studio was the first Atmos studio for music in France and it is certified Dolby Atmos Music Studio.
To illustrate the different tasks of his job, we take examples of albums remastered in Atmos from the original multi-track tapes that were archived.
Throughout this article, we will go through the different steps implemented from the recovery of the original tapes to the creation of the Atmos mix:
- Preparation of the tapes
- Playback of the tapes
- Digitization
- Restoration
- Mixing in Atmos
- Master generation
Poussin works on the archiving, restoration and mixing in Dolby Atmos of all Serges Gainsbourg’s albums, from Du chant à la une !… released in 1958 to You’re Under Arrest (1987). We will follow all the steps for two of these albums which represent 30 years of evolution of the technology of the magnetic tape, indeed, the first album was on a half-inch tape of 4 tracks in analog until digital in DASH 24 tracks.
In order to carry out the restorations of tapes of all the work of an artist, it is thus necessary to have a multitude of readers to be able to read the whole of the formats.
To better understand the different tape widths, here is an illustration which shows the different tape widths for studio tape, in comparison with the cassette.
To play all these varieties of tapes and to better understand this universe of professional tape players, I propose you a time travel with all the extraordinary equipment of this studio which allows to play all the possible formats. There is still a work of Poussin to maintain all these magnetos are in perfect working order and with a perfect calibration to allow the reading in the optimal conditions.
Visit of the studio
Let’s start with the visit of a mythical tape recorder, the Studer J37 model which was used by The Beatles. The Studer J37 revolutionized recording by bringing multi-track. It is a 4-track tape recorder in 1 inch from 1965, which means that one track uses ¼ inch, explaining the quality of the recordings for the time. There are over 50 tubes to operate this legendary machine.
| Model | Studer J37 (1965) |
| Tape Width | 1 inch ( 25,4 mm) (analog) |
| Number of tracks | 4 |
| Weight | 150 kg (330 lbs) |
| Power consumption | 500w |
| Tape speed | 15 and 7 ½ ips (38 et 19 cm/s) |
| Speed stability | 0.2% |
| Signal to noise ratio | RMS 65 dB at 15 ips, 60 at 7 ½ ips RMS weighted 76 dB at 15 ips, 70 at 7 ½ ips |
The Studer A80 is a legendary tape recorder that began its career in 1970. The A80 is declined in different models going from ¼ inch tape to 2 inches, allowing to go from 2 tracks to 24 tracks depending on the width of the tape used. The Studer A80 below is a version allowing to operate in 4 or 8 tracks depending on the width of the tracks chosen by changing the parts for the tape transport.
| Model | Studer A 80 (1970) |
| Tape Width | 0,5 or 1 or 2 inch ( 12,7 or 25,4 or 50,8 mm) (analog) |
| Number of tracks | 4 or 8 or 16 or 24 |
| Weight | 150 kg (330 lbs) |
| Power consumption | 320 w(1/4 inch), 400w (1/2 inch), 450w (1 inch), 800w (2 inchs) |
| Tape speed | 15 and 7 ½ ips (38 et 19 cm/s) |
| Speed stability | <0.1% |
| Frequency response | 15 ips 30-18 kHz, 7.5ips 30-15kHz +-2 dB |
| Signal to noise ratio | RMS* 62 dB at 15 ips, 62 at 7 ½ ips * 6 dB above operating level |
| Other | CCIR or NAB (switchable) |
After these 2 first machines, we arrive in another room which contains other machines of references in the world of the tape recorders.
In this room, we start with the analog tape recorders.
We find two Studer A80, the first one is a 2 inches model with 16 tracks which are perfectly distinguished on the photo of the heads. We find 3 heads; a head for erasing, a head for synchronous recording/playback during recording and a head for playback. The Studer A80 was used for the Pink Floyd album The Dark Side of the Moon.
Below is the second Studer A80 in the 1 inch 8 tracks version, the heads and capstan are made for the 1 inch tapes, and are half the height of the previous 16 track Studer A80. On the electronic side, only 8 circuits are used out of the 16. We can also easily count the 8 tracks visible on the heads.
The precision and stability of the tape speed is a very important point for the rendering and stability of the music. To have a maximum of precision, Poussin uses an external frequency generator perfectly stable with a frequency meter to perfectly adjust the rotation speed of the capstan at the frequency of 800 Hz.
Then we find 2 Studer A820 24 tracks 2 inchs with 2 chips strips. These two Studer A820 can be synchronized with a timecode to allow an operation in 48 tracks. The Studer A820 is a very sophisticated version of the A80. It accepts reels up to 14 inches (35.8 cm) for greater autonomy. Motor speed is controled by processor for better precision. Studer A820 has Slot for 24 noise reduction cards.
| Model | Studer A 820 (1984) |
| Tape Width | 2 inch (50,8 mm) (analog) |
| Number of tracks | 24 |
| Weight | 225 kg (495 lbs) |
| Power consumption | 1100w |
| Tape speed | 30 – 15 – 7.5 ips (76, 38, 19 cm/s) |
| Speed stability | <0.1% |
| Frequency response | 30 ips 50-20k, 15 ips 30-20 kHz, 7.5ips 30-15kHz |
| Signal to noise ratio | RSB 73 (30ips), 70 (15 ips), 71 dB (7,5 ips) (with NAB EQ) |
| Other | CCIR or NAB with cards Dolby A et SR timeCode synchronization |
The picture above shows one of the compartments of the A820 containing 8 noise reduction modules. Here, the modules installed are Dolby A-type noise reduction n°22. The Dolby A-type noise reduction was first introduced in 1965. It reduces the background noise by 10 to 15 dB. It is a noise reducer present in professional equipment. A simplified version, the Dolby B is used for cassettes (up to 10 dB of noise reduction in the high frequency range). The A820 can also be equipped with Dolby SR-type noise reduction modules (1986) which is capable of providing up to 25 dB of noise reduction in the high frequency range.
Adams Smith Zeta three allows the two A820s to be synchronized via a time code. We have the equivalent of a single 48 tracks tape recorder. To allow the two recorders to synchronize, it is necessary to keep a space of 30 seconds before the music to allow the synchronization.
The studio is also equipped with the DBX Type I noise reducer to ensure the greatest compatibility in tape playback. The picture below shows 3 DBX 158, each containing 8 DBX410 modules. The DBX Type I system provides 30 dB of noise reduction. It’s a classic 2:1 mirror image compander. It allows to obtain more than 100 dB of dynamics with the tape magnetophones.
3M digital multitrack recorder is the first digital multitrack recorder with 32 tracks on a 1 inch tape.
To work in 16-bits, it must combine 12- and 8-bits converters to obtain the full resolution. The 3M uses a 50 kHz sampling rate, the 44.1 and 48 kHz standards are not yet present. It is necessary to notice the particular path of the tape that is made to assure a continuous contact with the head to record the digital information without any loss. The electronics are also very dense, with one card per track to ensure the perfect setting of each channel.
| Model | 3M digital multitrack recorder (1978) |
| Tape Width | 1 inch (25,4 mm) (Digital) |
| Number of tracks | 32 tracks, 16 bits at 50 kHz |
| Weight | |
| Power consumption | 1800w |
| Tape speed | 45 ips |
| Speed stability | No measurable |
| Frequency response | 20 Hz to 18 kHz +- 0,3dB ; 10 Hz to 20 kHz +0,5 -3 dB |
| Signal to noise ratio | > 90 dB |
| Other | Two separate 12-bit and 8-bit converters combined to create 16-bit performance. Play time : 30 min with 10,5inchs Reels, 45 min with 14 inches reel |
The OTARI DTR-900 is the result of a partnership between Mitsubishi and Otari. The DTR-900 records 32 digital tracks on a 1 inch wide tape. The Mitsubishi 32-track version was used for Dangerous (Michael Jackson) album in addition to two 24-track Studer analog tape machines.
| Model | OTARI DTR-900 (1986) |
| Tape Width | 1 inch (25,4 mm) (Digital ProDigi) |
| Number of tracks | 32 tracks, 16 bit at 44.1 or 48 kHz |
| Weight | 88 kg (193 lbs)? |
| Power consumption | |
| Tape speed | 45 ips (115 cm/s) |
| Speed stability | – |
| Frequency response | 20 Hz to 20 kHz (+ 0.5 dB / -1 dB) |
| Signal to noise ratio | greater than 90 dB |
| Other | Timecode Mitsubishi and Otari collaborated on the design of the X-850 |
There are now 2 Sony PCM-3348 HD that can be synchronized to provide 96 tracks. The PCM-3348 HD with 48 tracks in 24 bits on 1/2 inch tape is the successor of the PCM-3324 24 tracks released in 1982 and which worked on 16 bits, and the PCM-3348 48 tracks released in 1989 also working on 16 bits.
| Model | Sony PCM-3348 HD (1997) |
| Tape Width | 1/2 inch (12,7 mm) (Digital) |
| Number of tracks | 48 tracks, 16/24 bit at 44.1 or 48 kHz |
| Weight | 220 kg (484 lbs) |
| Power consumption | 1200w |
| Tape speed | 30 ips (16 bits), 45 ips (24 bits) |
| Speed stability | – |
| Frequency response | 20 Hz to 21.7 kHz |
| Signal to noise ratio | ? |
| Other | 24 bits: 40 minutes (Fs=48.0 kHz) 16 bits: 60 minutes (Fs=48.0 kHz) Recording format DASH-PLUS/DASH-F Channel coding method HDM-1 |
We continue with the 2 track recorders. To continue with the digital magnetos, voice the Mitsubishi X86. Mitsubishi X86 ProDigit is known as one of the best digital tape recorders of the 80’s for its sound rendering. It works in 44.1 kHz and 48 kHz 16 bits. It is the successor of the X-80 (in 50.4 kHz) which was the first 2-track digital tape recorder from Mitsubishi. It is used for mastering and finalizing albums.
| Model | Mitsubishi X86 (1985) |
| Tape Width | 1/4 inch (6,3 mm) (Digital) |
| Number of tracks | 2, 16 bit at 44.1 or 48 kHz |
| Weight | – |
| Power consumption | – |
| Tape speed | 15 ips |
| Speed stability | +- 0,2% |
| Frequency response | 40Hz-15kHz +-0,5dB, 20Hz-20KHz +0.5-1dB |
| Signal to noise ratio | > 100 dB |
| Other |
The Sony PCM-3402 is in the Digital Audio Stationary Head (DASH) standard. This means that the head is fixed unlike the DAT which has a rotating head. The Sony PCM-3402 works in 16 bits 44.1 kHz or 48 kHz. It is like the X-86 used in mastering for the finalization of albums
| Model | SONY DASH PCM-3402 Digital |
| Tape Width | 1/4 inch (6,3 mm) (Digital) |
| Number of tracks | 2, 16 bit at 44.1 or 48 kHz |
| Weight | 88 kg (193 lbs) |
| Power consumption | – |
| Tape speed | 15 ips |
| Speed stability | – |
| Frequency response | – |
| Signal to noise ratio | – |
| Other |
We continue with a stereo analog tape recorder, the famous Studer A-810. The version presented here has 4 speeds from 3.75 ips (9.5 cm/s) to 30 ips ( 76 cm/s) to be able to read a maximum of tapes, it also has NAB and CCIR corrections that can be easily switched to adapt to the recording. It is entirely microprocessor controlled, both for the motor controls and for the audio adjustments (level, equalization with 256 adjustment steps).
In addition, a Dolby 363 noise reducer is used to ensure compatibility with Dolby A and Dolby SR noise reducers in order to obtain a very high level of performance for analog equipment.
| Model | Studer A 810 |
| Tape Width | 1/4 inch (6,3 mm) (analog) |
| Number of tracks | 2 |
| Weight | 30 kg (66 lbs) |
| Power consumption | 240w |
| Tape speed | 30 – 15 – 7.5 -3,75 ips (76, 38, 19, 9.5 cm/s) |
| Speed stability | +- 0,2% |
| Frequency response | 30 ips 40-22k, 15 ips 20-20 kHz, 7.5ips 20-16kHz, 3,75 ips 20-10kHz – +-2 dB |
| Signal to noise ratio | RSB 65 (30ips), 63 (15 ips), 62 dB (7,5 ips), 57 dB (3,75 ips) |
| Other | CCIR or NAB (for 7.5 and 15 ips) External Dolby A et SR TimeCode synchronization |
We finish with the famous Ampex ATR-104. The version presented here has 4 speeds from 3.75 ips (9.5 cm/s) to 30 ips ( 76 cm/s) to be able to read a maximum of tapes in 1/2 inch, it also has NAB and CCIR corrections to adapt to the recording. It works with 1/2 inch tapes, in 2 tracks or 4 tracks depending on the head installed. Poussin has the 2 types of heads, the machine is here installed with the 2 tracks head.
This is a legendary mastering machine with 2 tracks on 1/2 inch. The performance is very high with a tape range of 35-28000 Hz, and an unweighted signal to noise ratio of 72 dB without noise reduction. With a noise reducer like the Dolby Model 363 (Dolby A and SR NR), in Dolby SR, it provides a dynamic range of over 100dB.
| Model | Ampex ATR-104 (1977) |
| Tape Width | 1/2 inch (12,7 mm) |
| Number of tracks | 2 or 4 |
| Weight | 93 kg (205 lbs) |
| Power consumption | 600w |
| Tape speed | 30 – 15 – 7.5 -3,75 ips (76, 38, 19, 9.5 cm/s) |
| Speed stability | +- 0,08% |
| Frequency response | 30 ips 35-28k, 15 ips 30-20 kHz, 7.5ips 30-15kHz, 3,75 ips 30-10kHz – +-2 dB |
| Signal to noise ratio | RSB 72 (30ips), 70 (15 ips), 68 dB (7,5 ips), 64 dB (3,75 ips) |
| Other | CCIR or NAB (for 7.5 and 15 ips) External Dolby A et SR |
Here is a part of the equipment which is operational by Poussin (others are in the reserve).
It is necessary to realize that to maintain in working condition is an important work which requires to know all these tape recorders. To exploit all the qualities of these reference tape recorders, it is also necessary to fully master their operation and their characteristics.
These machines, some of them are very old, which require a precise adjustment.
Poussin has selected the best tape recorders in each category to have the maximum quality when reading old tapes and which are also found in reference in the Canadian Conservation Institute (CCI) Technical Bulletin 30.
Maintenance and calibration
Tape decks are fragile machines that require maintenance and calibration. Here are some of the necessary steps.
Tentelometer Tape Tension Gage
The playback of a tape is mechanical and can be done at high speed (30 ips, 76 cm/s), so it is important to not damage the tape and to control the tension of the tape being played. It is the role of the Tentelometer to measure the tension of the tape to ensure the proper setting of the tape magnetophones.
Pesola Dynamometer
Another important adjustment for the tape is the pressure of the pinch rollers with the capstan. It is the capstan that gives the speed of the tape. The precision depends on the speed setting and the pressure exerted on the tape with the pinch rollers. The pressure adjustment is done with a Pesola. This is very important with tapes that can be up to 50 mm wide (2 inches) and over 700 m long!
Demagnetizer
The playback and recording heads are composed of coils and magnets. With the passage of the tape, the magnetic flux accumulates in the heads. This flux can interfere with the playback or recording quality of the tapes. To eliminate this problem, the heads must be demagnetized regularly.
Calibration in playback and recording
Tape recorders are extremely powerful pieces of equipment, but they must also be calibrated. It is therefore necessary to use calibration tapes. Each standard tape has its own reading mode which includes :
Speed (ex: 15 ips, 38 cm/s)
Equalization (ex : CCIR)
the reference level (ex 355 nWb/m)
The tape provides 3 frequencies of qualibration at 0dB: 1 kHz, 100 Hz and 10 kHz. The pictures below show several calibration tapes with different bandwidths
Now that you know everything about the playback equipment used, we will be able to play a magnetic tape.
But there is a first step, the preparation of the reel.
Preparation of the tapes
Older tapes can become damaged over time. We do not read a tape directly. First, we proceed to an inspection of the tape to see the condition of it. Over time, many tapes become sticky, the layers being able to adhere to each other, this phenomenon is due to a degradation of the binder, the so-called “sticky shed syndrome“. The binder is based on polyester urethane and degrades in the presence of humidity. If you try to read these tapes, you risk their degradation but also clogging the tape recorder.
But fortunately, there is a solution, you have to heat the tape. For this Poussin has a special oven to perform this operation. Indeed, an exposure to a temperature of about 50°C for 6 to 24 hours, depending on the state of the tape, allows to restore the tape. It may still be necessary to clean the small dirt before reading the tape. Be careful, this is a delicate operation that requires experience, otherwise you can permanently damage your tape.
Playback of the tapes
Now that the tape is ready, we can read it. To do this we start by reading the information provided with the tape. Indeed, a tape of the same width can contain different information. It is important to know the number of tracks and the speed of the tape to choose the best player to use.
We must also identify the compensation circuit used CCIR (International Radio Communications Advisory Committee) or N.A.B (National Association of Broadcasters) depending on the origin of the tape, CCIR most used in France, NAB most used in UK, US.
These corrections also depend on the speed of the tape.
| 3,75 ips (9,5 cm/s) | 7,5 ips (19 cm/s) | 15 ips (38 cm/s) | 30 ips (76 cm/s) | |
| CCIR | 90 µs et 3180 µs | 70 µs | 35 µs | 17,5 µs |
| NAB | 90 µs et 3180 µs | 50 µs et 3180 µs | 50 µs et 3180 µs | 17,5 µs |
To avoid weak copying of the signal from one reel to another (Print through Effect), the tapes are stored wound (reel to right on the player).
When the tape is rewinded, you can switch to the calibration for the tape playback. Unlike pre-recorded tapes (with rare exceptions), there is no calibration signal. The tape starts with a 1 kHz calibration tone indicating the reference zero dB, for the more recent tapes there is also a 100 Hz and 10 kHz tones which allows to adjust the player settings.
In the case where a noise reducer has been used (Dolby A, Dolby SR or DBX Type 1), this calibration is also important to adjust the right reference level in order to have an optimal decoding, without any pumping effect due to the shift of the reference level.
4 Sample album
Now that all the previous steps are done, we can play the tape in the best conditions.
We will take the example of 4 albums that we will follow from the multi-track tapes to the distribution of the Atmos version, let’s continue with 4 albums of Serge Gainbourg :
Melody Nelson
Melody Nelson recorded in London and Paris in 1970 and finalized in the Studio des Dames (Paris) in 1971, the album was released in March 1971. This album has a multi-track recording with 8 tracks on a 1 inch tape (at the speed of 15 ips and CCIR equalization). This tape was played on the A80 8-track It has 7 tracks:
- Melody (7:34)
- Ballad of Melody Nelson (2:00)
- Waltz of Melody (1:32)
- Ah Melody (1:46)
- The mansion (4:08)
- In Melody (3:27)
- Cult Cargo (7:37)
N°4
N°4 was recorded at Studio Blanqui in Paris in 1962, available on a 25 cm mono vinyl, it contained 4 tracks on 1/2 inch:
- Les Goémons (2:37)
- Black Trombone (2:36)
- Baudelaire (2:26)
- Intoxicated Man (2:35)
- When you start (1:50)
- The Cigarillos (1:46)
- Requiem for a twister (2:38)
- This big bad you (2:20)
We find these 8 songs on a ½ inch tape (at the speed of 15ips CCIR) with only 3 tracks used out of the 4 available, this tape was played on the A80 4 track.
In 1963 4 tracks were released outside of album N°4:
- Naughty girl, bad boy (2:12)
- The slot machine (1:32)
- La Javanaise (2:27)
- Un violon, un jambon (2:21)
It is in 2001, in a remastered CD reissue that these 4 tracks will be integrated in the album as Bonus tracks.
These 4 tracks are taken from another ½ inch tape (at the speed of 15 ips NAB) and recorded at Studio Fontana in London in January 1963. This tape was played on the A80 4-track.
The fact that there are 2 tapes from 2 different recordings has its importance and we will come back to this point when listening to the Atmos versions.
Rock Around the Bunker
Rock Around the Bunker was recorded at Studio Philips in London in 1974. This album has a multi-track recording with 16 tracks on a 2 inch tape (at the speed of 15 ips, NAB equalization and Dolby A).
This tape was played on the A80 16-track. It has 10 songs:
- Nazi Rock
- Tata teutonne
- J’entends des voix off
- Eva
- Smoke Gets in Your Eyes
- Zig-zig avec toi (Sieg-sieg avec toi)
- Est-ce est-ce si bon ? (SS si bon ?)
- Yellow Star
- Rock Around the Bunker
- SS in Uruguay
L’Homme à la tête de chou
L’Homme à la tête de chou was recorded at Phonogram Studio in London in 1976 . This album has a multi-track recording with 24 tracks on a 2 inch tape (at the speed of 15 ips , NAB equalization and Dolby A). This tape was played on the A820 24-track. It has 12 songs:
- L’Homme à tête de chou
- Chez Max coiffeur pour hommes
- Marilou Reggae
- Transit à Marilou
- Flash Forward
- Aéroplanes
- Premiers symptômes
- Ma Lou Marilou
- Variations sur Marilou
- Meurtre à l’extincteur
- Marilou sous la neige
- Lunatic Asylum
More than 20,000 tapes saved
Poussin has done this work of digital preservation of all the albums of more than a hundred artists like : Jacque Brel, Johnny Hallyday, Mylène Farmer, Serge Gainsbourg, Jacques Brel, Georges Brassens, Édith Piaf, Vanessa Paradis, Patrick Bruel, Michel Polnareff, Laurent Voulzy, Alain Bashung, Barbara, Dalida, Michel Sardou, Michel Delpech, Charles Aznavour, France Gall, Renaud, Claude François, Jean-Jacques Goldman, Montreux Jazz Festival (from 1967)…
Digitization
The digitization stage is an important part, as it constitutes the transfer of the tape to digital format. It is therefore necessary to use modern converters like the Antelope Orion 32HD with its 32 inputs and 32 outputs.
In order to provide maximum quality for digital archiving, the 24-bit 192 kHz format is used for the digitization of tapes. For this, it is important to have a reference clock that can provide precision for the analog to digital converter. It is an Antelope Isochronous 10M clock with rubidium atomic clock that is used for all the studio covertisseurs. The stability of the clock is enormous, since there is not more than one second of deviation in 1000 years!
In addition to scanning the tape, all other information such as the tape cover and any notes available with the tape are scanned to keep all information and instructions attached to the tape.
Next steps
Now that all the tracks are digitized, the next steps will be the restoration and mixing in Atmos in the studio equipped in 9.1.8 that you will find in the second part of this report, with other examples of Atmos mixes including a concert of Johnny Hallyday and Mylene Farmer for the cinema, of realization of an SACD (with a full analogic mastering), Bluray Audio …
Magic Vinyl vs Digital 