FDN Reverb

[martinvicanek]

Hi gang,

Feedback Delay Network (FDN) reverbs are considered among the best algorithmic reverb designs. A number of parallel delay lines is configured, where each output feeds back into all other delay line inputs. As a result, echoes are generated with rapidly increasing density.

However, for most parameter sets the sound is not pleasant to the ear due to mode clustering in the frequency domain, which is perceived as ringing. Only by careful selection of the delay lengths is it possible to suppress this ringing to an acceptable level.

Another design characteristic is the number of delay lines used. I have not obtained satisfactory reslts with fewer than 16.

The atached optimized implementation is comparable in terms of CPU demand to the (likewise optimized) Freeverb. As to the sound quality, judge for yourself!

Have fun!

[adamszabo]

Very nice Martin! I am still trying to understand it, does it consist of early and late reflections? Or its just one series of delays?

[rocknrollkat]

Hi gang,

The atached optimized implementation is comparable in terms of CPU demand to the (likewise optimized) Freeverb. As to the sound quality, judge for yourself!

Have fun!

Hi Martin,
I'm sure this reverb sounds great, but it will not run on my machine.
I get full 'dry' sound, but no reverb,even with the 'mix' pot at full CW.
I see that you are calling up 'SSE', which according to Flowstone, my computer lacks.
I tried upgrading to Flowstone 3.0.8 a few weeks ago, and I got the error message "Sorry pal, you don't have SSE", so I'm running 3.0.7.
I ran a scan of my machine and it seems to indicate that I do have SSE, and of course I can't find the program that generated that report !
I'm familiar with Feedback Delay Networks (FDN), and Hadamard matrices, but I stopped programming with Assembly on the 6502 a few decades ago, so most of what you're doing escapes me.

ROXY

[Spogg]

That sounds excellent Martin and, obviously, it works fine on my core i7 (gen 2) system.

I've experimented with mutltiple delay lines for reverb myself, but this is the business!

Thanks for sharing

Spogg

[adamszabo]

I see that you are calling up 'SSE', which according to Flowstone, my computer lacks.

Almost any computer has SSE, but indeed when I exported the reverb as an effect vst it didnt make any sounds for me either, so I had to connect an instrument module before the reverb to make it do anything. Maybe Martin can check whats going on.

[rocknrollkat]

I see that you are calling up 'SSE', which according to Flowstone, my computer lacks.

Almost any computer has SSE, but indeed when I exported the reverb as an effect vst it didnt make any sounds for me either, so I had to connect an instrument module before the reverb to make it do anything. Maybe Martin can check whats going on.

Hi Adam,
That's what I thought as well.
Interesting that your DAW doesn't 'see' the reverb !
Mine plays the 'through' signal, but not the 'mixed' signal.
Hopefully Martin has some ideas !
In response to the post about allpass oscillation, Martin built a proper allpass network, I built a demonstrator that shows Martin's is correct, freeverb's is flawed.
I'll post my demonstrator in a minute.

ROXY



ROXY

[martinvicanek]

Sorry to hear some of you guys have propblems with this. I have exportetd it as an VST effect and can use it in Reaper no problem. The schematic does use, however, assembly opcodes which seem to require FS 3.0.8 or higher. Like Adam I don't think that SSE should be an issue.

[rocknrollkat]

Sorry to hear some of you guys have propblems with this. I have exportetd it as an VST effect and can use it in Reaper no problem. The schematic does use, however, assembly opcodes which seem to require FS 3.0.8 or higher. Like Adam I don't think that SSE should be an issue.

Martin, I mentioned earlier that when I tried to upgrade to Flowstone 3.0.8, I was told that I don't have SSE, and therefore, no 3.0.8 for me !
My computer says otherwise, I ran a CPU checker program that says I have SSE.
I has forced to run 3.0.7, which works fine, but if I need 3.0.8 to run your project, as we say in the 'states, "no dice".
Anyway, thanks again for that great allpass filter !

ROXY

[Spogg]

I mentioned earlier that when I tried to upgrade to Flowstone 3.0.8, I was told that I don't have SSE, and therefore, no 3.0.8 for me !

This SSE message comes with any situation where there is a version conflict of some sort. It’s normally got nothing to do with SSE availability. Not very helpful for diagnosis!

For example, if I try to load a 3.09 schematic into 3.08.1 I get the SSE message. You can always load a previous version schematic into a later version of Flowstone.

I don’t know why you’re getting it though. Did you try to do a dual installation to keep the original? If so, you need to edit the registry in Regedit to point to the desired installation path. Just search for flowstone in Regedit and edit the path. Otherwise FS will access the wrong support files and give the SSE message.

Cheers

Spogg

[rocknrollkat]

I mentioned earlier that when I tried to upgrade to Flowstone 3.0.8, I was told that I don't have SSE, and therefore, no 3.0.8 for me !

This SSE message comes with any situation where there is a version conflict of some sort. It’s normally got nothing to do with SSE availability. Not very helpful for diagnosis!

For example, if I try to load a 3.09 schematic into 3.08.1 I get the SSE message. You can always load a previous version schematic into a later version of Flowstone.

I don’t know why you’re getting it though. Did you try to do a dual installation to keep the original? If so, you need to edit the registry in Regedit to point to the desired installation path. Just search for flowstone in Regedit and edit the path. Otherwise FS will access the wrong support files and give the SSE message.

Cheers

Spogg

Hi Spogg,
I was doing a 'clean install', I use a program called "Revo Uninstaller" which cleans the registry of all items it can find pertaining to the program it's uninstalling.
I tried to reinstall 3.0.8 several times, nope, no 3.0.8 for me !
I try to be a thorough as possible.
I routinely save my toolbox files as .fsm's and re-install them on the later install.
Also a good idea for routine protection, in case Flowstone has to be re-installed.

And I've had that happen.

ROXY