Hi Fons,
On 16/10/2024 15:23, Fons Adriaensen wrote:
Hello all,
The purpose of this post is to gather some opinions on the
use of 'tape distortion' plugins.
[...]
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>
[...]
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'.
Very interesting and always nice to see new ideas and active
developments in LAD (and LAU) land :-)
From more of a LAU perspective (I know this is LAD, but still hopefully
useful), the sort of 'basic' question is: what would the use case for
this be?
If it were more for production I think it could be interesting to
understand how a precise algorithm / code for tape emulation would
compare with a 'perceptual' emulation (possibly EQ + noise + some
compression + some distortion?)...
If I understand correctly by 'simulated' you mean using more
'traditional' effects like EQ etc.? Would you share what you did? Just
'reverse engineered' the final sound resutlt?
For example, I have recently been using more (or at least more
frequently) distortion on certain Yoshimi instrument patches. While I
quite dislike the use (and abuse) of terms like 'warmer', 'vintage' and
'analogue'... this does produce as a, desired, side effect some
interesting compression, interesting EQ-ing and noise which do overall
give a nice character to some of the sounds.
But I do this very much 'by ear' as it depends a lot on the actual
instrument, song etc.
A totally different direction could be using a plug-in like this to
'simulate' accurately tape and different tape types / parameters to
conduct listening tests (e.g. A/B/X) without having to use actual tape
and tape machines, eventually to (try and) study in a more scientific
manner what are the basis of claimed 'superiority' of tape (in some
cases even cassette (!)) by then linking the results to audience
demographics, music genre, measurable or observable sound qualities etc.
Of course this last one would require a research institution /
researcher(s) interested in conducting this kind of study, and no I
didn't search extensively if it's already been done, a quick search
engine check didn't find anything interesting with some studies maybe
relevant (I don't have subscriptions to some of the publishing
platforms) [0][1][2].
Also: why tape (or vynil) are 'perceived' to be better is quite evident
intuitively, so would it really work to study it more scientifically? :-)
My two cents, hope they are useful
Lorenzo
[0] https://journals.sagepub.com/doi/abs/10.2466/pms.1989.68.3c.1079
[1] https://www.sciencedirect.com/science/article/abs/pii/S016981411630004X
[2] https://tech.ebu.ch/docs/techreview/trev_274-hoeg.pdf
Comments invited !!
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