16 Oct
2024
16 Oct
'24
3:23 p.m.
Hello all,
The purpose of this post is to gather some opinions on the
use of 'tape distortion' plugins.
The way an analog magnetic tape recorder distorts the signal
is quite complicated. The non-linear response is mainly due
to the hysteresis of the magnetisation process, and how this
interacts with the HF bias added to the recorded signal.
Simplifying things a bit, as the tape moves past the recording
head and away from it, it goes through several cycles of an
hysteresis loop with decreasing amplitude, and it finally
converges to some value more or less proportional to the signal.
The bias signal itself does not remain on the tape, or at most
at a very low level.
The same process but with just a very high level HF bias is
used to erase the tape.
Simulating this accurately is quite complicated, and very CPU
intensive. The sample rate must be at least twice the bias
frequency (around 100 kHz for 'pro' equipment) and for each
sample you need to evaluate the hysteresis loop up to a hundred
times (depending on tape speed) to simulate the convergence.
Over the past few months I've written the code to do this,
with the aim to present a useful 'tape emulation' plugin
at the next LAC. It uses a somewhat simplified form of the
Preisach algorithm for the hysteresis.
<http://kokkinizita.linuxaudio.org/linuxaudio/downloads/preisach-model.pdf>
But the first results are somewhat sobering.
Have a look at
<http://kokkinizita.linuxaudio.org/linuxaudio/downloads/tapesaturation.png>
This shows the tranfer function (recorded magnetic signal as
a function of the input) for three values of the HF bias.
The blue line is what you get without bias. It result in a
very smooth saturation for high level signals, but a low
amplitude signal will be severly distorted due to the flat
region around zero.
As bias level is increased, this effect is reduced and the
low level gain increases up to some maximum. This is shown
by the orange curve.
The recommended way to set the correct bias level is to
further increase it until the small signal gain is reduced
by a few dB (typically 1 or 2 dB, depending on tape type).
This is shown by the green curve.
The central part of this is very linear (less than 1% THD).
But now the smooth saturation is almost transformed into
hard clipping. The sharp bend in the curve occurs when the
signal amplitude is higher than the bias amplitude.
The only effect that remains in a complete simulation is
the result of the EQ applied to the signal to be recorded.
Higher frequencies have a 'self erasure' effect (which is
nicely reproduced by the simulation) and so need to be
amplified. The net result is that they will saturate at
a lower input level.
How much EQ is required depends mainly on tape speed, higher
speeds need less. At the most popular 'pro' speed (381 mm/s)
this would be something around 10 dB at 10 kHz. At the higher
(762 mm/s) speed typically used for 'master tapes' it's just
a few dB.
So what does effectively remain of the 'smooth saturation
and compression' that is claimed to give tape recording its
magical 'warm' character ? Is it just a myth ?
I also simulated the green curve directly without going
through the complicated full simulation, and honestly,
to me that sounds just the same. And unless you really
use very high levels (much more than would actually be
used) the net effect is marginal. Maybe the hard clipping
can be useful when applied to individual tracks (e.g.
drums or bass), but then there are much simpler ways
to do this than 'tape emulation'.
Comments invited !!
16 Oct
16 Oct
5:57 p.m.
Take what I say with a large grain of salt as I am both a software engineer
and electrical engineer with a large strictly hardware only studio with 152
inputs, 16 effect sends and 16 subgroups.
I own a real tape delay - largely similar to a Roland Space echo with
similar looks and dimensions - that anyone can buy new today: the EchoFix
ef-x2 for $1999 that includes a reverb tank and digital chorus, while their
ef-x3 with an analog chorus is $2699.
When talking about the tape bias levels, the EchoFix is around 50hz and is
annoying enough that I high pass filter it out. EQ is one of the areas the
cheap clones haven't conquered yet imho and I use API 550a/550b mostly so I
am unclear if digital EQ is going to help in emulation.
The EchoFix prices have been dropping and imho it is only a matter of time
before there is competition at the lower end by Berhinger etc - who by the
way kind of proves my point as their kt-1176 compressor has dropped from
$499 to $150 today.
My point here is that with a plethora of proprietary tape plugins that also
emulate the Ampex recorders that I used the real ones first hand while in
audio engineering school in the early 90's, as well as new hardware tape
delays on the market, I wonder if it's a little late now.
In all that I do applaud your efforts as it is a difficult software
problem, in my mind close to impossible when hearing the proprietary
efforts being so far off.
On Wed, Oct 16, 2024 at 3:24 AM Fons Adriaensen <fons(a)linuxaudio.org> wrote:
Hello all,
The purpose of this post is to gather some opinions on the
use of 'tape distortion' plugins.
The way an analog magnetic tape recorder distorts the signal
is quite complicated. The non-linear response is mainly due
to the hysteresis of the magnetisation process, and how this
interacts with the HF bias added to the recorded signal.
Simplifying things a bit, as the tape moves past the recording
head and away from it, it goes through several cycles of an
hysteresis loop with decreasing amplitude, and it finally
converges to some value more or less proportional to the signal.
The bias signal itself does not remain on the tape, or at most
at a very low level.
The same process but with just a very high level HF bias is
used to erase the tape.
Simulating this accurately is quite complicated, and very CPU
intensive. The sample rate must be at least twice the bias
frequency (around 100 kHz for 'pro' equipment) and for each
sample you need to evaluate the hysteresis loop up to a hundred
times (depending on tape speed) to simulate the convergence.
Over the past few months I've written the code to do this,
with the aim to present a useful 'tape emulation' plugin
at the next LAC. It uses a somewhat simplified form of the
Preisach algorithm for the hysteresis.
<http://kokkinizita.linuxaudio.org/linuxaudio/downloads/preisach-model.pdf
But the first results are somewhat sobering.
Have a look at
<http://kokkinizita.linuxaudio.org/linuxaudio/downloads/tapesaturation.png
This shows the tranfer function (recorded magnetic signal as
a function of the input) for three values of the HF bias.
The blue line is what you get without bias. It result in a
very smooth saturation for high level signals, but a low
amplitude signal will be severly distorted due to the flat
region around zero.
As bias level is increased, this effect is reduced and the
low level gain increases up to some maximum. This is shown
by the orange curve.
The recommended way to set the correct bias level is to
further increase it until the small signal gain is reduced
by a few dB (typically 1 or 2 dB, depending on tape type).
This is shown by the green curve.
The central part of this is very linear (less than 1% THD).
But now the smooth saturation is almost transformed into
hard clipping. The sharp bend in the curve occurs when the
signal amplitude is higher than the bias amplitude.
The only effect that remains in a complete simulation is
the result of the EQ applied to the signal to be recorded.
Higher frequencies have a 'self erasure' effect (which is
nicely reproduced by the simulation) and so need to be
amplified. The net result is that they will saturate at
a lower input level.
How much EQ is required depends mainly on tape speed, higher
speeds need less. At the most popular 'pro' speed (381 mm/s)
this would be something around 10 dB at 10 kHz. At the higher
(762 mm/s) speed typically used for 'master tapes' it's just
a few dB.
So what does effectively remain of the 'smooth saturation
and compression' that is claimed to give tape recording its
magical 'warm' character ? Is it just a myth ?
I also simulated the green curve directly without going
through the complicated full simulation, and honestly,
to me that sounds just the same. And unless you really
use very high levels (much more than would actually be
used) the net effect is marginal. Maybe the hard clipping
can be useful when applied to individual tracks (e.g.
drums or bass), but then there are much simpler ways
to do this than 'tape emulation'.
Comments invited !!
_______________________________________________
Linux-audio-user mailing list -- linux-audio-user(a)lists.linuxaudio.org
To unsubscribe send an email to
linux-audio-user-leave(a)lists.linuxaudio.org
11:34 p.m.
On Wed, Oct 16, 2024 at 05:57:33AM -1000, robertlazarski wrote:
When talking about the tape bias levels, the EchoFix
is around 50hz and is
annoying enough that I high pass filter it out.
You may have the wrong idea about what 'bias' is in this context.
The bias used in analog tape recording is typically in the 100 kHz
range, and even for 'consumer' level equipment at least 50 kHz.
Ciao,
--
FA
5:58 p.m.
On Wed, 16 Oct 2024 15:23:44 +0200
Fons Adriaensen <fons(a)linuxaudio.org> wrote:
So what does effectively remain of the 'smooth
saturation
and compression' that is claimed to give tape recording its
magical 'warm' character ? Is it just a myth ?
I guess it’s similar to Vinyl, where certain characteristics steming
from technical limitations are perceived to sound ‘nice’, with a dosis
of nostalgia. While at the same time, the fidelity under good conditions
is actually quite high. Thus a good simulation of that can only be
subtle, which increases the likelyhood that some EQing sounds about the
same.
I used to have Korg M1 workstation as my only means of producing music
and would record finished pieces on casette tape. In one case I wanted
more of a punk rock sound and oversteered the recorder. As far as I
remember, the distortion set in in a very good natured, gentle fashion
and maxed out with a rumbling, compressed sound that still left
everything recognisable. Digital distortion effects tend to be brutal
in comparison.
Maybe the simulation is more interesting if you strive outside
realistic parameters?
--
Thorsten Wilms <t_w_(a)freenet.de>
11:29 p.m.
On Wed, Oct 16, 2024 at 05:58:19PM +0200, Thorsten Wilms wrote:
... While at the same time, the fidelity under good
conditions
is actually quite high. Thus a good simulation of that can only be
subtle, which increases the likelyhood that some EQing sounds about
the same.
:-)
As far as I
remember, the distortion set in in a very good natured, gentle fashion
and maxed out with a rumbling, compressed sound that still left
everything recognisable. Digital distortion effects tend to be brutal
in comparison.
Maybe the simulation is more interesting if you strive outside
realistic parameters?
I'm pretty sure that is true. But my original aim was to make
a processor that would emulate a 'pro' quality tape recorder
as close as possible - I even planned to have user accessible
alignment controls for bias, level, and HF gain. But the result
so far is just 'to good'...
Probably few people today realise how good professional analog
tape recorders - Studer, Ampex, Nagra, Telefunken - had become
in the late 80s. At one of the places I worked we had a 24-track
with Telcom C4 noise reduction. Never noticed any noise or
distortion on that one.
OTOH I also remember many occasions when (mostly classical)
musicians heard a digital recording of themselves for the first
time. The were just totally excited by the fidelity, none of
them ever complained it sounded 'cold'.
Ciao,
--
FA
18 Oct
18 Oct
8:48 a.m.
[Thorsten Wilms]
On Wed, 16 Oct 2024 15:23:44 +0200
Fons Adriaensen <fons(a)linuxaudio.org> wrote:
> So what does effectively remain of the 'smooth saturation
> and compression' that is claimed to give tape recording its
> magical 'warm' character ? Is it just a myth ?
...
Maybe the simulation is more interesting if you strive
outside
realistic parameters?
This++. I think that if there is merit to the way tape distorts a
signal, it seems more worthwhile to establish the principles of the
transformation and then let your taste determine the way.
Cheers, Tim
16 Oct
16 Oct
8:53 p.m.
Le 16/10/2024 à 09:23, Fons Adriaensen a écrit :
Hello all,
The purpose of this post is to gather some opinions on the
use of 'tape distortion' plugins.
The way an analog magnetic tape recorder distorts the signal
is quite complicated. The non-linear response is mainly due
to the hysteresis of the magnetisation process, and how this
interacts with the HF bias added to the recorded signal.
Simplifying things a bit, as the tape moves past the recording
head and away from it, it goes through several cycles of an
hysteresis loop with decreasing amplitude, and it finally
converges to some value more or less proportional to the signal.
The bias signal itself does not remain on the tape, or at most
at a very low level.
The same process but with just a very high level HF bias is
used to erase the tape.
Simulating this accurately is quite complicated, and very CPU
intensive. The sample rate must be at least twice the bias
frequency (around 100 kHz for 'pro' equipment) and for each
sample you need to evaluate the hysteresis loop up to a hundred
times (depending on tape speed) to simulate the convergence.
Over the past few months I've written the code to do this,
with the aim to present a useful 'tape emulation' plugin
at the next LAC. It uses a somewhat simplified form of the
Preisach algorithm for the hysteresis.
<http://kokkinizita.linuxaudio.org/linuxaudio/downloads/preisach-model.pdf>
But the first results are somewhat sobering.
Have a look at
<http://kokkinizita.linuxaudio.org/linuxaudio/downloads/tapesaturation.png>
This shows the tranfer function (recorded magnetic signal as
a function of the input) for three values of the HF bias.
The blue line is what you get without bias. It result in a
very smooth saturation for high level signals, but a low
amplitude signal will be severly distorted due to the flat
region around zero.
As bias level is increased, this effect is reduced and the
low level gain increases up to some maximum. This is shown
by the orange curve.
The recommended way to set the correct bias level is to
further increase it until the small signal gain is reduced
by a few dB (typically 1 or 2 dB, depending on tape type).
This is shown by the green curve.
The central part of this is very linear (less than 1% THD).
But now the smooth saturation is almost transformed into
hard clipping. The sharp bend in the curve occurs when the
signal amplitude is higher than the bias amplitude.
The only effect that remains in a complete simulation is
the result of the EQ applied to the signal to be recorded.
Higher frequencies have a 'self erasure' effect (which is
nicely reproduced by the simulation) and so need to be
amplified. The net result is that they will saturate at
a lower input level.
How much EQ is required depends mainly on tape speed, higher
speeds need less. At the most popular 'pro' speed (381 mm/s)
this would be something around 10 dB at 10 kHz. At the higher
(762 mm/s) speed typically used for 'master tapes' it's just
a few dB.
So what does effectively remain of the 'smooth saturation
and compression' that is claimed to give tape recording its
magical 'warm' character ? Is it just a myth ?
I also simulated the green curve directly without going
through the complicated full simulation, and honestly,
to me that sounds just the same. And unless you really
use very high levels (much more than would actually be
used) the net effect is marginal. Maybe the hard clipping
can be useful when applied to individual tracks (e.g.
drums or bass), but then there are much simpler ways
to do this than 'tape emulation'.
Comments invited !!
Although the focus here is on signal reproduction, for truly realistic
tape simulation
maybe later wow-and-flutter and dropouts could be simulated.
It always seemed, at least with cassette, that even a brand new
mid-to-high-end machine
with a fresh tape has these problems, according to our measuring
instruments.
If these might be considered inherent defects of tape systems, then why not
even go a bit further and add other real-world defects which occur
later on.
One setting picks the tape drive: From cheap cassette deck to pro
reel-to-reel.
Another setting picks the type of 'defect': From cheap DC capstan motors to
felt idler clutch pads whose fibers magically compress over time in
such a way
as to cause 'micro-dragging' which increases the flutter - or even
squealing noises,
to cheap miniature pinch rollers, or pinch rollers that have become
warped or dirty.
Another setting picks the tape, but also simulates how many times it's
been played:
From pristine unopened box to 'your older brother's Van Halen/Led
Zeppelin car mix tape'.
Cheers.
Tim.
17 Oct
17 Oct
7:37 a.m.
New subject: [LAD] Tape emulation - is it worth the effort ?
On 16 October 2024 13:23:44 UTC, Fons Adriaensen <fons(a)linuxaudio.org> wrote:
But now the smooth saturation is almost transformed
into
hard clipping. The sharp bend in the curve occurs when the
signal amplitude is higher than the bias amplitude.
The only effect that remains in a complete simulation is
the result of the EQ applied to the signal to be recorded.
Higher frequencies have a 'self erasure' effect (which is
nicely reproduced by the simulation) and so need to be
amplified. The net result is that they will saturate at
a lower input level.
How much EQ is required depends mainly on tape speed, higher
speeds need less. At the most popular 'pro' speed (381 mm/s)
this would be something around 10 dB at 10 kHz. At the higher
(762 mm/s) speed typically used for 'master tapes' it's just
a few dB.
So what does effectively remain of the 'smooth saturation
and compression' that is claimed to give tape recording its
magical 'warm' character ? Is it just a myth ?
IMO you've nailed it.
The non-mythical aspect is, as you mentioned, the EQ boost, its impact on saturation, and
the *almost* (but not quite) hard clipping. Depending on the tape setup being
used/emulated, the net effect can be anything from mildly noticeable to completely
imperceptible.
Any effect beyond that is indeed a myth.
Is that effect worth the hassle of using tape, or accurate tape emulation? Almost never.
As you point out, there are often simpler ways, today, to achieve the same effect.
(Plus, great-sounding records have been made without tape or accurate emulation since the
1980s. Tracy Chapman's 1987 debut album, recorded on a Mitsubishi 850[1], is a prime
example.)
I also simulated the green curve directly without
going
through the complicated full simulation, and honestly,
to me that sounds just the same. And unless you really
use very high levels (much more than would actually be
used) the net effect is marginal. Maybe the hard clipping
can be useful when applied to individual tracks (e.g.
drums or bass), but then there are much simpler ways
to do this than 'tape emulation'.
Again, I completely agree.
But I'd add these observations.
Use-case 1.
Many people are stubborn and irrational. Relieving people of any given myth can therefore
be difficult or impossible. Presenting a person with evidence that their belief is
mythical can upset them, and they may respond by dismissing the evidence rather than the
myth! (Historical examples abound: the Oxford Movement - the "Puseyites" -
explicitly advocated "faith over reason",[2] and that attitude is surprisingly
common in all areas of human endeavour, including audio production.)
Pragmatically, then, when a person in the chain (artist, engineer, producer, consumer)
believes tape or tape emulation is worthwhile, it may be simpler to humour them than to
risk the recording (or even marketing) process collapsing against those beliefs. Hence
much of the continuing market for tape and emulators.
(The desire for tape can be due to other factors in addition to "warmth". It can
also come from a desire to avoid post-production. The White Stripes and their fanbase were
an example of this c.2002,[3][4] as were Rage Against The Machine about a decade
earlier.)
Use-case 2.
There are people with access to a PC but without access to tape, who will want to be able
to learn, as closely as possible, how tape sounded. The more accurate your algorithm, the
better it suits this purpose, i.e. as a teaching tool.
Some of those people will end up concluding, as you correctly did, that there are often
simpler ways to achieve equivalent results. But your emulator will have been an important
part of that education.
Conclusion
Thank you for working on this and for sharing your results!
Sam
[1]: https://www.mixonline.com/recording/classic-track-fast-car-tracy-chapman-42…
[2]:
https://www.oxfordbibliographies.com/display/document/obo-9780199799558/obo…
[3]: https://www.newcutstudios.co.uk/cant-ignore-the-elephant-in-the-control-room
[4]: https://www.soundonsound.com/people/liam-watson-toe-rag-studios
19 Oct
19 Oct
10:30 p.m.
On Wednesday, October 16, 2024 8:23:44 AM CDT Fons Adriaensen wrote:
The way an analog magnetic tape recorder distorts the
signal
is quite complicated.
...
Have a look at
<http://kokkinizita.linuxaudio.org/linuxaudio/downloads/tapesaturation.png>
This shows the tranfer function (recorded magnetic signal as
a function of the input) for three values of the HF bias.
What is your guess at how many studios correctly biased their recorders?
The orange trace in your graph looks like fairly soft saturation. Do you
think under-biasing like that would have been common during the time tape was
common, or would most facilities have correctly biased up to the more linear
curve with harder saturation?
The only effect that remains in a complete simulation
is
the result of the EQ applied to the signal to be recorded.
The inverse is applied on playback? Wouldn't a high cut shelf type filter
applied to a clipped signal make it sound a little more like soft saturation?
--
Chris Caudle
20 Oct
20 Oct
11:31 a.m.
On Sat, Oct 19, 2024 at 03:30:56PM -0500, Chris Caudle wrote:
Maybe, but exactly the opposite was done - HF was attenuated in the
record path and boosted on replay [1]. The reason for this is that HF
signals are not only attenuated by the magnetic recording process, they
also saturate at lower magnetic flux levels [2]. It's just not possible
to record them at the same high level as LF signals. So in order to
provide full level output at HF, they must be boosted on replay.
[1] In order to ensure that a tape recorded on machine A could be
replayed on machine B, tape machines were aligned to a level and
EQ standard. What was standardised was not the actual equalisers
used, but the level and frequency response of the magnetic signal
on tape. All standards specified a first order lowpass for this
in the record path, e.g. -3dB at 3180 Hz for the NAB standard
used in the USA.
[2] The actual parameter that controls this is not frequency,
but wavelength on tape, i.e. tape speed divided by frequency.
This is the main reason why higher speed is better.
Ciao,
--
FA
What is your guess at how many studios correctly
biased their recorders?
The orange trace in your graph looks like fairly soft saturation. Do you
think under-biasing like that would have been common during the time tape was
common, or would most facilities have correctly biased up to the more linear
curve with harder saturation?
I've never heard of such practice, nor remember it ever mentioned in the
professional media, e.g. Studio Sound monthly magazine.
Keep in mind that sound engineers at the time were not looking for what
is today hyped as 'tape sound' - they just wanted the highest quality.
Also the minimum tape speed used in music recording studios was 15 IPS
(38 cm/s), 8 times the speed of a Compact Casssette, and master tapes
often used 30 IPS. This provided a much higher quality than most people
imagine today. And once noise reduction systems (Dolby-A, DBX, Telcom-C4)
were available there was much less need to record at very high levels.
The only
effect that remains in a complete simulation is
the result of the EQ applied to the signal to be recorded.
The inverse is applied on playback? Wouldn't a high cut shelf type filter
applied to a clipped signal make it sound a little more like soft saturation? 
7:35 p.m.
the circuit for Rec & Repro heads affects the sound very different,
all tape machines / brands had a "sound" different than others,
some aimed to clean & transparent sound, like late Studer
but most tape machines sound different, each had a flavour,
there are plugins that emulate that, like Steinberg Yamaha Vintage Open Deck,
emulates 3x decades of Studer + 1x Ampex ATR-100,
allows different Rec & Repro circuits, but all same US EQ,
Not the same as Real Tape.
Avid Heat plugin for DSP sounds very nice, for CPU Not much...
the Heat name is misleading, does Not have Tube emulation is Tape,
toneboosters emulated Teac & Revox, etc...
circuits were very different:
old MCI JH-16 / 24 had custom Transformer i/o to balance / un-balance the signal,
but later models were replaced with custom op-amps mci 2001,
dont have direct replacement, most people replaced with 5532 "works" but Not the
same,
all op-amps have a "sound", depending on the impedance of the circuit,
because op-amps are miniaturized discrete amplifier circuits like jensen 990, api, etc...
Ampex MM-1000 1100 1200 machines had optional hi-fi rec & repro boards with Lundlah
transformer,
some companies went to extreme levels, created Tube Amplifiers for Repro.
most Pro Studios had MRL Calibration Tapes, there is tons of Tutorials on YouTube,
but small home studios used machines as is, from factory,
No cabliration unless done by local technician.
some machines had US Eq, and others Euro EQ,
NAB / IEC
if you record on Euro EQ circuits
or if you record on US EQ circuits,
and playback on the other circuit, affects the sound, one sounds brighter, the other
darker,
some artist used that for creative purposes.
old Cakewalk Fx-2 tape machine emulation DX plugin
had that ability to select different curves, but the sound its "CPU".
a very popular tape plugin emulation today for "Digital Home Studios"
are the Universal Audio DSP, but i like more Avid DSP.
UAD allows to change Bias, and stuff like Steinberg plugin,
Avid only has 1 know that does All.
https://www.manley.com/legacy/thpa
https://reel-reel.com/tape-head-preamps/
https://bottlehead.com/product/tube-repro/
https://www.erhard-audio.com/Titan.html
http://www.dehavillandhifi.com/222_Tape_Preamp.htm
https://rtzaudio.com/legacy/
________________________________________
From: Fons Adriaensen <fons(a)linuxaudio.org>
Sent: Sunday, October 20, 2024 4:31 AM
To: linux-audio-user(a)lists.linuxaudio.org
Subject: [LAU] Re: Tape emulation - is it worth the effort ?
On Sat, Oct 19, 2024 at 03:30:56PM -0500, Chris Caudle wrote:
Maybe, but exactly the opposite was done - HF was attenuated in the
record path and boosted on replay [1]. The reason for this is that HF
signals are not only attenuated by the magnetic recording process, they
also saturate at lower magnetic flux levels [2]. It's just not possible
to record them at the same high level as LF signals. So in order to
provide full level output at HF, they must be boosted on replay.
[1] In order to ensure that a tape recorded on machine A could be
replayed on machine B, tape machines were aligned to a level and
EQ standard. What was standardised was not the actual equalisers
used, but the level and frequency response of the magnetic signal
on tape. All standards specified a first order lowpass for this
in the record path, e.g. -3dB at 3180 Hz for the NAB standard
used in the USA.
[2] The actual parameter that controls this is not frequency,
but wavelength on tape, i.e. tape speed divided by frequency.
This is the main reason why higher speed is better.
Ciao,
--
FA
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Linux-audio-user mailing list -- linux-audio-user(a)lists.linuxaudio.org
To unsubscribe send an email to linux-audio-user-leave(a)lists.linuxaudio.org
What is your guess at how many studios correctly
biased their recorders?
The orange trace in your graph looks like fairly soft saturation. Do you
think under-biasing like that would have been common during the time tape was
common, or would most facilities have correctly biased up to the more linear
curve with harder saturation?
I've never heard of such practice, nor remember it ever mentioned in the
professional media, e.g. Studio Sound monthly magazine.
Keep in mind that sound engineers at the time were not looking for what
is today hyped as 'tape sound' - they just wanted the highest quality.
Also the minimum tape speed used in music recording studios was 15 IPS
(38 cm/s), 8 times the speed of a Compact Casssette, and master tapes
often used 30 IPS. This provided a much higher quality than most people
imagine today. And once noise reduction systems (Dolby-A, DBX, Telcom-C4)
were available there was much less need to record at very high levels.
The only
effect that remains in a complete simulation is
the result of the EQ applied to the signal to be recorded.
The inverse is applied on playback? Wouldn't a high cut shelf type filter
applied to a clipped signal make it sound a little more like soft saturation?
10 Dec
10 Dec
5:28 a.m.
I recently saw that the (North America) Pacific Northwest section of the Audio
Engineering Society has a webinar soon on comparing tape emulation.
https://aes2.org/events-calendar/2024-12-11-is-it-memorex-or-is-it-emulatio…
2024-12-11: "Is it Memorex or Is It Emulation?" A listening comparison of
tape vs hardware emulation vs software emulation
--
Chris Caudle
48
days inactive
103
days old
linux-audio-user@lists.linuxaudio.org
11 comments
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Chris Caudle -
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Tim -
Tim Goetze