Analog magnetic tape has long been a reference medium used by the biggest bands on machines that are legends today, such as the Studer J37 used by the Beatles or the Studer A80 used by Pink Floyd for their album The Dark Side of the Moon.
Whether stereo or multitrack, with bandwidths from 1/4″ to 2″, tape has been used to produce thousands of albums and masters. I had the chance to see and listen to these marvellous tape recorders, and you can find all the information I obtained during my visit to the DES studios.
Today, analog media are once again very much in evidence, particularly vinyl. Cassettes are also making a comeback, and there’s also an offer for tapes.
Tapes are offered as a copy (or copy of a copy) of an analog master, or a copy of a digital master.
More widely available, vinyl, even when produced from a digital master, brings its own personality and sound.
But, what about tape?
Tape has a number of advantages over vinyl: it doesn’t crack when played, and there’s no surface noise due to the mechanical playback of vinyl.
On the other hand, depending on the tape recorder used, tape can have a background noise that can be reduced with noise reducers, enabling us to offer a very wide dynamic range for this medium.
To compare the rendering of the tape with a digital reference, we’re going to record 10 musical samples from different digital media and in different formats: PCM 24 88.2, DSD64 (SACD), DSD 256, DXD (24-bit 352 kHz)… Several musical styles are represented: Classical, Jazz, Rock, Pop, like Patricia Barber, Miles Davis, Tsuyoshi Yamamoto Trio, Oscar Peterson, Gnomus, Thomas Schirmann, Anne Bisson, Michael Jackson, Dire Straits, Roxy Music.
The tracks selected for testing have not undergone intensive treatment with a brickwall limiter.
For the recording, we use a TEAC A3440 (2 tracks) and a Dolby Model 363 with Dolby SR noise reducer. The tape is a Recording The Masters SM900 and the tape recorder has been calibrated for this tape.
Before comparing the extracts, here are a few curves characterizing operation on analog tape versus a digital reference.
Let’s start with the bandwidth: the straight line (blue) is the digital version (perfectly linear over the entire spectrum up to 88 kHz), and in white the tape, we see a linear bandwidth rising above 20kHz, with attenuation below 40Hz.
The spectrum above represents a 1 kHz signal from the digital (blue) and the band (white).
Analysis of these curves shows us :
- The digital signal is perfect, with minimal background noise.
- There’s a perfect superposition of the 1 kHz signal between the digital and the tape, above the noise floor of the tape.
- Distortion measured for the tape is 0.2%. The yellow arrows show the frequency peaks corresponding to harmonic distortion.
- The band signal (white) present throughout the spectrum corresponds to the band’s background noise. It may seem high compared to the digital ideal, but the noise is -85 dB at 300 Hz and even lower as the frequency rises, which is very good.
Now that the technical specifications have been presented, here’s a comparison of the extracts.
The reference tracks were recorded on SM900 tape at 38cm/s (15ips) with Dolby Model 363 SR, and played back with 24-bit 176.4 kHz digitization.
The first comparison concerns the measurement of dynamics, comparing the DR of the reference excerpts with those recorded on tape.
As can be seen, the dynamics of the tape recordings are the same, with only a difference of one for one track (17 instead of 18).
| Titles | Digital | Tape TEAC A3440 |
| Patricia Barber – This Town | DR12 | DR12 |
| Miles Davis – So What | DR11 | DR11 |
| Tsuyoshi Yamamoto Trio – Misty for direct cutting | DR13 | DR13 |
| Oscar Peterson – You Look Good To Me | DR9 | DR9 |
| Gnomus – Mussorgsky (Fritz Reiner) | DR12 | DR12 |
| Thomas Schirmann – Too Yong To Die | DR12 | DR13 |
| Anne Bisson – Killing Me Softly | DR12 | DR11 |
| Michael Jackson – The Girl Is Mine (with Paul McCartney) | DR13 | DR12 |
| Dire Straits – Private investigation | DR15 | DR16 |
| Roxy Music – Avalon | DR13 | DR13 |
Tape preserves the original dynamics of the recordings.
For the next measurement, presented for each sample, we will compare the spectrum of the digital sample with that of the sample recorded from magnetic tape.
The final stage of this test is listening. For each track, we have the original extract and the result of the tape recording. This makes it easy to compare the sound of the tape with that of the original.
Sample 1: Patricia Barber – This Town
The sample of the song “The Town” comes from the 24-bit 352.8 kHz DXD digital file.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 1 digital original and transfer to tape.
Sample 2: Miles Davis – So What
The “So What” track sample comes from the direct analog HDTT transfer from tape to DXD as a 24-bit 352.8 kHz DXD digital file.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 3: Tsuyoshi Yamamoto Trio – Misty (for direct cutting)
The “Misty” track sample comes from the direct recording in DSD256.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 4: Oscar Peterson – You Look Good To Me
The “You Look Good To Me” track sample comes from the SACD in DSD64.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 5: Gnomus – Mussorgsky (Fritz Reiner)
The “Gnomus” track sample comes from the SACD in DSD64.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 6: Thomas Schirmann – Too Yong To Die
The “Too Yong To Die” track sample comes from the digital Master file in 32 bits 88.2 kHz.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 7: Anne Bisson – Killing Me Softly
The “Killing Me Softly” track sample comes from the 24-bit 96 kHz digital file.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 8: Michael Jackson – The Girl Is Mine (with Paul McCartney)
The “The Girl Is Mine” track sample comes from the SACD in DSD64.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 9: Dire Straits – Private investigation
The “Private investigation” track sample comes from the MOFI SACD in DSD64.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Sample 10: Roxy Music – Avalon
The “Avalon” track sample comes from the SACD in DSD64.
The graph below shows the spectra of the original version in blue, and the tape transfer version in white.
Both samples 2 digital original and transfer to tape.
Does tape give music a specific sound?
The answer is yes, tape recording brings its own personality to music, and in this test we found a softer, warmer sound, while retaining detail, naturalness and dynamic range. Of course, rendering can vary according to the tape recorder used, the tape used and the recording level, but there will always be a specific rendering.
That’s why some sound engineers use an analog tape pass in the final mix, to bring out that specific tape sound, some even choose to use tape recorders with tube electronics, and others even switch back to analog entirely!
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Please explain the
*As can be seen, the dynamics of the tape recordings are the same, with only a difference of one for one track (17 instead of 18).*
Im not making sense with it