[LAU] Impulse Resonance Reverbs

[hgn]

Hello LAU list,

I would like to get an overview what impulse resonance reverbs exist in
Linux, in which format and which is the highest quality (sound &
performance).

I am not 100% sure if that is even the right term; what I mean is a
reverb where you load a sound file that the reverb program uses to
calculate the reverb of a signal.

Do you have recommendations which are good? Do you have recommendations
which programs are bad?

Greetings,

hgn

[Jeanette C.]

Post by hgn
Hello LAU list,
I would like to get an overview what impulse resonance reverbs exist in
Linux, in which format and which is the highest quality (sound &
performance).

Hi there,
to answer you other question first: they are called impulse response
reverbs or IR for short. They are also known as convultion reverbs,
since that is what is done with the IR.

There are quite a few: jconvolver is a standalone program, I believe
there is also a GUI version of that. The guitarix suite of plugins packs
an IR reverb plugin in LV2 (and maybe LADSPA) format. There is also
ir.lv2, another LV2 plugin. You might also be able to run a few VST IR
reverbs.

All these reverbs, that I know, load plain audiofiles of the IR
(wav/aiff). Some of
these programs come with a few IRs packaged alongside. If you search for
impulse responses you will find a lot of free ones on the net of all
kinds of rooms. I'd say most of them are churches, possibly followed by
concert and theatre halls. But there are all kinds of more unique
spaces.

I wouldn't know if any one of the named ones is known to be particularly
inefficient, but at a guess I'd say: no. They should all be fine. It may
be a question of further features inside the plugins, like filtering or
manipulation of the IR to adapt the reverb.

HTH.

Best wishes,

Jeanette
...

--------
* Website: http://juliencoder.de - for summer is a state of sound
* SoundCloud: https://soundcloud.com/jeanette_c
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Skip on the drinks Head to the floor
Makin' my way Past the show
My body's taken over And I want some more <3
(Britney Spears)

[Ralf Mardorf]

I'd say most of them are churches, possibly followed by concert and
theatre halls.

A lot, if not most of impulse response recordings available for free as
in beer aren't from churches, concert and theatre halls, they are
recordings from stand alone reverbs of a company world-renowned for
it's digital reverbs. Regarding Wikipedia the vendor

"is considered "the godfather of digital reverb""

;)

[David Kastrup]

Post by Ralf Mardorf

I'd say most of them are churches, possibly followed by concert and
theatre halls.

A lot, if not most of impulse response recordings available for free as
in beer aren't from churches, concert and theatre halls, they are
recordings from stand alone reverbs of a company world-renowned for
it's digital reverbs. Regarding Wikipedia the vendor
"is considered "the godfather of digital reverb""

Maybe I need to figure out the impulse response (and find a way to
emulate it with reasonably sparsely populated filter structures) of the
spring reverb in my rotating "Solton Turbojet" speaker.

[Ralf Mardorf]

Post by David Kastrup

Post by Ralf Mardorf

I'd say most of them are churches, possibly followed by concert and
theatre halls.

A lot, if not most of impulse response recordings available for free
as in beer aren't from churches, concert and theatre halls, they are
recordings from stand alone reverbs of a company world-renowned for
it's digital reverbs. Regarding Wikipedia the vendor
"is considered "the godfather of digital reverb""

Maybe I need to figure out the impulse response (and find a way to
emulate it with reasonably sparsely populated filter structures) of the
spring reverb in my rotating "Solton Turbojet" speaker.

I've got a small guitar amp at hand with a small spring reverb. In
dislike this spring reverb and never use it. Since I don't have the
room to store my huge keyboard amp, I permanently borrow it a friend,
but I'm missing it's large spring reverb a lot.

I once visited an orchestra recording done by a famous American audio
engineer. I was deeply impressed of the amazing reverb. The reverb
available by the French sound studio truck used by the American
engineer was a professional, aged L...egend. But no, the engineer
didn't use this "L"everb. The reverb was made by two overhead
"N"icrophones. This time my employer made "B"icrophones. I suspect the
"B"icrophones as well as any other large (and perhaps even small)
diameter microphones would have done the job of the "N"icrophones, too.

If we have the fortune to get reverb by an original spring, that isn't
too small or by a real hall made for music performance, we should use
it, if we could.

Sometimes we might not have the microphone, or the build in DI box of
the keyboard amp is fishy and does produce unwanted noise (mine is
a Peavey KB-300 ;).

[David Kastrup]

Post by Ralf Mardorf

Post by David Kastrup
Maybe I need to figure out the impulse response (and find a way to
emulate it with reasonably sparsely populated filter structures) of the
spring reverb in my rotating "Solton Turbojet" speaker.

If we have the fortune to get reverb by an original spring, that isn't
too small

It takes one side of the amp (35cm or so?), has about 4 springs in it.

Post by Ralf Mardorf
or by a real hall made for music performance, we should use it, if we
could.
Sometimes we might not have the microphone, or the build in DI box of
the keyboard amp is fishy and does produce unwanted noise (mine is a
Peavey KB-300 ;).

Oh, this thing is _far_ too noisy for recordings off a DI. It's sort-of
ok for live. But if you managed to model the impulse response, the
noise would be gone.

[Ralf Mardorf]

By accident send off-list, a chance for me to correct at least two
typos.

Date: Sat, 1 Sep 2018 21:45:04 +0200
From: Ralf Mardorf <***@alice-dsl.net>
To: David Kastrup <***@gnu.org>
Subject: Re: [off-topic] [LAU] Impulse Resonance Reverbs

Post by David Kastrup

Post by Ralf Mardorf
Sometimes we might not have the microphone, or the build in DI box of
the keyboard amp is fishy and does produce unwanted noise (mine is a
Peavey KB-300 ;).

Oh, this thing is _far_ too noisy for recordings off a DI.

Good point! I still guess the integrated DI box is fishy, but I also
guess you have got a point there. I borrow this keyboard amp a friend
and we compared it with a Roland Cube keyboard amp, a "classic" one.
Within my recollection the Roland Cube did sound better or at least not
less good than the Peavey KB-300, but in direct comparison the
Peavey KB-300 did sound way better. I always regretted that I bought
the Peavey KB-300 instead of the Roland Cube, because of the weight of
the Peavey and the insane handhold on to of it, instead of handholds on
^^top
each side, but nowaday while a friend is using it, I guess I made the
^^^^^^^ nowadays
right choice a long time ago.

[Ralf Mardorf]

Post by hgn
I would like to get an overview what impulse resonance reverbs exist
in Linux, in which format and which is the highest quality (sound &
performance).

Hi,

sound and performance of Fons reverbs are excellent. Jconvolver is what
you are looking for.

Zita-rev1 is an algorithm reverb, unfortunately it only provides one
character, but the one provided is excellent.

However, Fons' reverbs suffer from bad user friendliness. A workaround
for Zita-rev1 is usage of the GXZita_rev1-Stereo plugin. IIRC there also
is a GX version available for Jconvolver, but IIRC it does use the same
impulse response for the left and right channel, instead of using
individual impulse response recordings for the left and right channel.

https://kokkinizita.linuxaudio.org/linuxaudio/

Regards,
Ralf

[Christopher Arndt]

Post by hgn
Do you have recommendations which are good? Do you have recommendations
which programs are bad?

Almost thre years ago I gave a short presentation with an overview of
available reverbs on Linux at our local open source audio meeting
(http://oscamc.de). Here are the somewhat sketchy notes:

https://chrisarndt.de/talks/linuxreverbs/

In the meantime, there are a few new developments (see below), but this
may still be helpful.


Nowadays, I find this convolution reverb to be the most versatile and
overall best working:

http://lsp-plug.in/?page=manuals&section=impulse_responses_stereo

LV2 URI: http://lsp-plug.in/plugins/lv2/impulse_reverb_stereo

The licensing is somewhat unusual, though.


The other convolutions reverbs I have used in the past are:

* Klangfalter (LV2 and VST)

The LV2 version has issues with the GUI display: on re-opening GUI, the
window is very small and can't be resized anymore.

The VST version works, but I prefer to use LV2 plugins if I can.


* ir.lv2 (https://github.com/Anchakor/ir.lv2)

Doesn't compile with zita-convolver 4.x


Chris

[Fons Adriaensen]

Post by Christopher Arndt
* ir.lv2 (https://github.com/Anchakor/ir.lv2)
Doesn't compile with zita-convolver 4.x

That's easy to fix.

Find the line(s) where the 'configure()' method is called.
There will 6 parameters, add a 7th one at the end with value 1.0f.

Ciao,

[Christopher Arndt]

Post by Fons Adriaensen

Post by Christopher Arndt
* ir.lv2 (https://github.com/Anchakor/ir.lv2)
Doesn't compile with zita-convolver 4.x

That's easy to fix.
Find the line(s) where the 'configure()' method is called.
There will 6 parameters, add a 7th one at the end with value 1.0f.

Turns out that I was using an outdated forked repo of ir.lv2. The
original repo (which was down for some time) already has a fix.

But the GTK+ 2 based GUI of the plugin still poses problems with some
hosts (e.g. Carla reports warnings about outdated LV2 properties and
only shows the generic GUI). It seems to work fine with jalv.gtk though.


Chris

[Christopher Arndt]

Post by Christopher Arndt

Post by Christopher Arndt
* ir.lv2 (https://github.com/Anchakor/ir.lv2)

It seems to work fine with jalv.gtk though.

Unfortunately it doesn't. Saving/Loading LV2 presets does not work,
since no reference to the impulse response file is saved. I now remember
why I switched to the forked repo in the first place ;)

Anyway, I can't really recommend ir.lv2 at this time.


Chris

[Chris Caudle]

Post by Christopher Arndt
* ir.lv2 (https://github.com/Anchakor/ir.lv2)
Doesn't compile with zita-convolver 4.x

As you pointed out, the original lv2.ir has a commit to support new
zita-convolv since June:
https://github.com/tomszilagyi/ir.lv2/commit/b61260ac4ba7410fdbcc27e62209bd810ddc5a55

The 1.3.4 release was after that, should include the commit:
https://github.com/tomszilagyi/ir.lv2/releases

[Michael Jarosch]

Inspired by hgn's question about impuls response reverbs:
Are there some convolution engines that can be used for building a
digital crossover network? Or can I just feed the IR-reverbs with
inverted impulse responds of the speakers I want to make a correction
for?

Greets?
Mitsch