Thanks to all for the input. I'll reply separately to the points in each.
On 05/02/25 19:13, Doug Lee wrote:
>> 2) It is exactly the same as "echo" with different (and more) parameters
> I thought it differed from echo in that successive echos created by
"echos" are included in what is fed into
> the next echo in the effect. This would indeed mean that inputs to
second and subsequent echos are replaced,
> as part of the function of the effect.
echos does this (you need fixed-width font here!)
In--+--------+-------------------+-------------------->| |
| | | * gain-in | |
____v___ _v_ ________ _v_ ________ | |
| | | | | | | | | | | |
| delay1 | | + |-->| delay2 | | + |-->| delayN | | |
|________| |___| |________| |___| |________| | | * gain-out
| ^ | ^ | | +
|------------>
| | | | | | | Out
| | | | +--------->| |
| | | | * decay N | |
| | +--------+-------------------->| |
| | * decay 2 | |
+--------+---------------------------------------->| |
* decay 1 |___|
So yes, delay2in is (delay1out + In) but the net result is that
delay2out is (In delayed by delay2) + (In delayed by (delay1+delay2))
and these two are exactly equivalent:
sox_ng --no-dither in.au out.au echos .5 .5 1000 .5 300 .5
sox_ng --no-dither in.au out.au echo .5 .5 1000 .5 300 .5 1300 .5
and so on for 3 delays etc.
In fact, the test suite tests specifically that to test echo and echos
against each other. (I say sox_ng, not sox, only because that's
the only place it actually works!)
If the echo-in-series effect is in fact what you need,
it can be considered a syntactic shorthand, but I doubt that anyone
ever needs specifically that. There's nothing like that in the DSP
literature
or in any other package that I know of.
> Didn't know that either, but I do use the silence effect often,
> and probably sometimes with unusual parameters - like durations of 0.
The more I hear of the silence effect, the more problems I hear it has.
I found out today that if you have audio that peaks midway at -1dB,
to remove everything after (or before) that peak, you have to specify
-3.95dB. -3.94 leave the entire recording intact.
> my failure to weigh in before the "filter" effect was removed
> because I subsequently tried to use the FM broadcast filter example
out of the
> manual only to find I didn't know how to replace that effect in the
example.
I didn't know about that; I wasn't following SoX in 2011.
If it did something you needed it can probably be put back now
though I haven't even looked at what it did yet.
In general I am against removing stuff, or even making it work "better"
because someone on the other side of the planet will have used what
it does to create a piece of music or in a script or called from another
program, and changing/removing stuff is a great way to break other
people's work by remote control, without even knowing you're doing it.
For example, there are compositions written in Csound in the 1980s
that render bit-perfect with today's Csound the same as they did
when they were written under MS/DOS.
In my case, I wanted to test many different versions of SoX and
had to sniff the version numbers and select -2 and -c 2 acording
to how old it was. If they had kept honouring -2 as an alias,
even undocumented, it would have made thing easier.
Unfortunately there was a deprecation/removal frenzy some time
before 14.4.2 so it's a bit late now, but I would avoid another one.
M
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