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Does anybody know if tech exists to tune a reverb or echo effect to specific notes? I know that different room dimensions offer different resonating frequencies, but can this effect be manipulated electronically? Does anybody know of tools for that or transformation techniques to achieve it?
Thanks,
Dusan

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RemyRAD Wed, 11/09/2011 - 23:08

Electronic reverb, be it software or hardware can only respond to the notes that are generated. Pitching effects of the reverb can be performed in unreal time, in your software. You cannot tune a reverb per se. You can tune its decay time, pre-delays, diffusion but you cannot tune into a single note if the note wasn't performed. A reverb generates no sound of its own, is not a musical instrument and is designed to do just one thing, reverberate. Obviously, you're asking this question as you have some creative idea that you would like to hear this effect happen in. One of the things that can be tuned by the crossover points to vary the difference of low-frequency decay times & high-frequency decay times but that's about it. This is not to say that what you want to happen can't be done. It can be. One does not need to mix the original sound source with the reverberated sound. And because of that, you could input what you wanted into the reverb in its pure reverberated state. You would then create the pitching effect and adjust how much and how deep the reverb should be. So your question is basically one of recording and mixing technique than an effect. This is where audio engineers like us can go completely bonkers, crazy, nutty to create an unusual sound. It's not something you can just put a quarter in, turn the crank and get. You have to think outside the effects box for this.

When I saw your question, I was thinking about my former EMT plate reverb. Those cold rolled steel sheet metal plates had to be tuned like a guitar, a violin, a piano. That's because the plate is tensioned very tightly. It is supported at two places in each corner. It can be quite difficult to tune properly as the directions to do so is rather vague, confusing, outrageous. The tuning procedure was important to make that reverb sound really sweet or like you accidentally ran over it with your car. But that was all. Spring reverbs could be stretched and tensioned but only at the factory. Sure, some really cheap ones had a knob to tension or loosen a spring. But none could ever change the pitch of the reverb, only its quality.

So what Ya thinkin'?
Mx. Remy Ann David

Kapt.Krunch Thu, 11/10/2011 - 05:05

dusanyu, post: 379017 wrote: ...tune a reverb or echo effect to specific notes....I know that different room dimensions offer different resonating frequencies, but can this effect be manipulated electronically?

EQ.

On a copied 100% wet reverb track, find 'resonating frequencies' (specific notes) you want accentuated, cut frequencies outside that (or 'those', if wanting more than one) with an EQ, then, mix back in with dry track to desired strength. If you want to emulate, say, only a 6kHz resonance 'bump', reduce everything around that, then sneak it back into the mix.

You can decide if you want to just add that copied/manipulated 6kHz 'boost' back in alongside the dry track and the original 100% wet track...or just not use the original wet track, and leave the desired strength of original reverb in the new track by lowering the surrounding frequencies levels by a certain amount.

To clarify, you'll probably want three tracks to start with. The original dry one, the original natural 100%-wet reverbed one, and a copy of the original 100%-wet reverbed one. Manipulate the copy of the reverbed one, leaving the original for either a starting-over point, or a possible mix-in track along WITH the manipulated one.

Make sense?

As always, I may be wrong...but I'm sure I'll be set right, if I am.

Kapt.Krunch

dusanyu Thu, 11/10/2011 - 08:22

Thanks so much for a very thoughtful reply RemyRAD. I never thought that this could be done by a push of a button currently -- partly because I never heard of it and partly because there aren't many use cases for it. Also, I don't know if doing this in realtime can happen because of the complexity of the signal processing. I know that physical reverb cannot be tuned but I was wondering of simulating the effect of selective reverb which with enough tweaking could approximate a perfectly tuned room (even if it is unrealistic).

I had thought of filtering along the method described by Kapt. Krunch. I am a software developer by trade and have studied psychoacoustics quite a bit in school, but not audio engineering or signal processing of any kind. Based on both of your responses, my next few of questions are:

1) Are there EQs fine enough to select particular frequencies through (perhaps even a set of distinct frequencies)? I am familiar with only very general EQs that control a range of frequencies.

2) What tools can one use to do this in realtime?

3) Kind of the same question, but what technologies do you think I could use for this that somebody with a programming background (not audio engineering) background could use?

4) Who could I find to help me make something like this the right way, and something that is usable in realtime and ideally portable (rack, box, etc.)?

Many thanks guys!
Dusan

RemyRAD Thu, 11/10/2011 - 09:08

Okay here is another one. The pitched reverb effect, I actually used back in 1978. I had worked on a recording of this piece which was the fine arts "modern music", based upon Edgar Allan Poe's, the Telltale Heart. Since we had a record this on location with a small specialized orchestra, we took out the 4 track, 1/4 inch, 3340. I got back to the studio to mix this. The finale ending was a peculiar dissonant chord of instruments that sustained this chord. Since I was using the EMT 140 ST, I also had it on a tape delay on the Echo send, effectively creating a pre-delay. The ending was rather uneventful until I flanged the reel on the Echo send tape delay to the plate. This of course bent the pitch down and then back up again upon the removal of my talented finger. It went into the plate reverb that way which sounded really spooky producing this ethereal pitched reverb. Well they loved that. They duplicated that performance again elsewhere, which I also recorded. Upon the mix down, they wanted that same effect again, in the same place, in the same way. Thankfully that was repeatable but it did take a couple of takes to get the flanging of the pitch just right since we didn't have anything automated back in 1978. At least not at our studio with the exception of a Lexicon Prime time 41 which we got shortly thereafter. And we weren't using any VCA fader based automation either. So this is a purely analog way to get a spooky effect in 1978 before the Apple II ever saw the light of day.

It's time for flanging for dollars. Let's see who our first contestant is?
Mx. Remy Ann David

Kapt.Krunch Thu, 11/10/2011 - 09:52

Perhaps I'm confused? I read it as wishing to emulate a room that accentuated some frequencies over others, those frequencies being the same pitch as the dry signal. Remy SEEMS to be speaking of pitch-changing the reverb? I can see doing something of a doppler effect to bend it down as it appears to gain distance...or even just doing an odd effect of a static pitch-change, for unusual artistic reasons...both of which would involve pitch changes, as opposed to frequency node manipulation.

I thought it was an odd request to wish to impart things INTO a track that most people fight to eliminate...but who am I to question someone's artistic vision? Maybe they just want it to sound like a space they like playing in, and like that certain imperfection? Maybe it sounds fresh and new?

Anyway...that's why my previous response.

Kapt.Krunch

RemyRAD Fri, 11/11/2011 - 00:03

Sorry about my misinterpretation to your question. You can always put an equalizer on the send or on the return. With a parametric or 1/3 octave, 31 band graphic equalizer, you can certainly focus in on a particular frequency, accentuating that on the send which will cause the reverb unit or reverb algorithm to be more highly excited at your chosen frequencies. This can make the reverb sound deeper on those particular accentuated by the equalizer, notes. So on the input with the equalizer, it will over excite the reverb unit or algorithm at the frequencies in which you choose. Conversely, on the return or output of the reverb, equalization will emphasize certain spectral areas of the reverb decay in a much different way than on the send. One could even utilize a parametric sweep equalizer to manually track and reinforce numerous musical notes & frequencies. That function, depending upon software may be automatable or may require real-time hand riding. That's why you have to be a good engineer to understand what you want to do in a proper technical manner. I mean couldn't you tell me what I need to know on the test to become a brain surgeon? I always thought that Jethro Bodine would have done a great job for Gabrielle Giffords? But he must've been more of an analog brain surgeon instead of a digital brain surgeon since he knew how to align her head? Maybe that's why he's the brain surgeon and I'm only an audio engineer?

I would imagine it requires some talent to put all of that Texas tea into bags?
Mx. Remy Ann David