Spring reverb

Algorithm development and general DSP issues

Moderator: frank

Post Reply
Aion
Posts: 33
Joined: Sat Mar 22, 2008 1:17 am

Spring reverb

Post by Aion »

At first thank you very much for developing the FV-1. Very excellent job. I wish I had such chip some twenty years ago:)

My question: how to simulate the spring reverb, used in guitar amplifiers?
frank
Posts: 1244
Joined: Wed Oct 19, 2005 12:26 pm
Contact:

Post by frank »

Hi Aion,

Simulating a spring reverb is a bit difficult due to the "twerp" of the spring. I have not seen any research papers on it, most papers try to simulate the reverb of a room and not a spring. I'll look around and see if I can find any info.

-Frank
Frank Thomson
Experimental Noize
Aion
Posts: 33
Joined: Sat Mar 22, 2008 1:17 am

Post by Aion »

Hi Frank!

I see you developed a spring reverb in your SKRM‐C8‐XXX daughterboard. Could you detail the code of that please?

How/where to order SKRM‐C8‐XXX in small quantity in EU?

Thank you in advance!
frank
Posts: 1244
Joined: Wed Oct 19, 2005 12:26 pm
Contact:

Post by frank »

Hi Aion,

We are not releasing details of that code at this time, it is one of the effects that gives us a competitive edge over the other module makers and if we posted details of the code they could copy it.

Currently no EU distributors for the SKRM-C8, hopefully soon. We do ship to any country so we can ship to you. If you know others that are interested in the module maybe you could arrange a group buy to lower costs.
Frank Thomson
Experimental Noize
livingston
Posts: 131
Joined: Sun Nov 15, 2009 3:37 pm
Location: New Orleans, LA US

Post by livingston »

Did you work out a way to protect code in the EEPROM? I don't want to reverse engineer your code, but rather I was interested in protecting code, but you said in another thread that it's not possible.
frank
Posts: 1244
Joined: Wed Oct 19, 2005 12:26 pm
Contact:

Post by frank »

No, the code is not protected. If someone just lifts the code it will be obvious if we compare the code, the structure will be the same. If someone does it via a white room technique they may reproduce the effect but it will have a different structure, unique to their work and analysis and different from ours.
Frank Thomson
Experimental Noize
livingston
Posts: 131
Joined: Sun Nov 15, 2009 3:37 pm
Location: New Orleans, LA US

Post by livingston »

Frank, I understand that you don't want to give away the code, but could you at least send us in the right direction regarding what makes a spring algo different from a regular reverb?

I haven't really delved into reverb programs to understand how they tick, but to me it seems like the spring sound has to do with resonance at a few frequencies. I would imagine that high feedback in a short delay line would produce some of that metallic ringing.

Any thoughts?
livingston
Posts: 131
Joined: Sun Nov 15, 2009 3:37 pm
Location: New Orleans, LA US

Post by livingston »

livingston wrote:Frank, I understand that you don't want to give away the code, but could you at least send us in the right direction regarding what makes a spring algo different from a regular reverb?

I haven't really delved into reverb programs to understand how they tick, but to me it seems like the spring sound has to do with resonance at a few frequencies. I would imagine that high feedback in a short delay line would produce some of that metallic ringing.

The "twirp" sound could likely be done with an envelope-controlled filter, so that part doesn't seem to challenging to me.

Any thoughts?
djmalan
Posts: 36
Joined: Fri Mar 06, 2009 8:22 am

Post by djmalan »

I haven't really delved into reverb programs to understand how they tick, but to me it seems like the spring sound has to do with resonance at a few frequencies. I would imagine that high feedback in a short delay line would produce some of that metallic ringing
.

+ Freqency of the input signal and some feedback from the box or from the enviroment vary the delay time of the spring . :D In my opinion this is the main difference from the other reverbs (like frequency dependent delay time)
soundsubs
Posts: 24
Joined: Fri Feb 25, 2011 11:49 am

Post by soundsubs »

a Spring Alg is exciting to me. Anyone got anything?
IvoJ
Posts: 1
Joined: Wed Jul 09, 2014 7:10 am

Spring reverb

Post by IvoJ »

Hi to you all !!

It's some time ago since 2011, doese anyone have more information how to implemente a spring reverb in the FV-1 Board? Or if someone has a complete spn-File to share or to sell ??

Thanks a lot !!
noouch
Posts: 1
Joined: Fri Sep 26, 2014 8:10 am

Post by noouch »

I was looking in to this a few days back, and the most helpful paper I could find on the subject was this one:

http://asp.eurasipjournals.com/content/ ... 646134.pdf

In short, you need to figure out a way to efficiently model the varying speed of different frequencies traveling through the spring to produce the chirp.
Digital Larry
Posts: 338
Joined: Mon Nov 12, 2012 1:12 pm
Contact:

Post by Digital Larry »

Thanks for the link! I do not believe that the FV-1 has the resources to accomplish everything described in this paper. Nevertheless it's a great place to start. I've found that multi-tap delays seem have a greater first-order similarity to spring reverb than regular "smooth" reverbs.

I used to have a Johnson J-Station modeler (Pod knock-off) that seemed to have a sampled "bwip" that would play back with every note. It was the same sound on every note you played. It did not rattle when you kicked the unit, unfortunately. That's my favorite feature of spring reverbs. :D
amz-fx
Posts: 38
Joined: Wed Sep 06, 2006 7:06 am
Location: Louisiana, USA
Contact:

Post by amz-fx »

There have been a number of papers by Parker, Bilbao and others presented at the DAFx conferences. Interesting reading but somewhat technical in nature.

Info: Spring Reverbs

regards, Jack
Digital Larry
Posts: 338
Joined: Mon Nov 12, 2012 1:12 pm
Contact:

Post by Digital Larry »

Thanks for the links!

Funny how something which was developed as an approximation of the initial desired goal becomes the goal many years later and is also more difficult to achieve with technological advances than the original goal (acoustic reverberation).
Post Reply