Unwanted resonance

Started by Mikeyboy, July 07, 2009, 10:20:29 AM

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Here's a question for you ambient production gurus.. I've been recording some interesting (to me anyway) recordings with guitar, ebow, reverbs etc, all with software plugins. Although I'm pleased with some of the results, there's some annoying resonances in the mids that I just can't get rid of.

I've tried EQ, dynamic compression, drastic EQ(!) and I can improve the situation slightly, but I'm really trying to get those smooth velvety drifts I hear when listening to stuff like Steve Roach, Vidna Obmana etc.

I've got a piece here that demonstrates the issue:

I actually have a better example at home that I'll try to upload.

Any advice greatly appreciated!  :)



Can you adjust your reverb's cutoff frequency to limit the amount of verb applied to the mids? 

It sounds like the verb trails are not allowed to die off before new ones start; this is common with an ebow.  Try adjusting your playing style - when one swell of sound starts to rise, back off the ebow and start another swell on a different note, preferably one that won't resonate with the first.  If the resonance is in the guitar, you can also just mute all the strings that are not being bowed.  If the resonance is in the verb, then you need to find a way to tweak the parameters to limit the trails in the mids.

I wish I was a Glowworm; a Glowworm's never glum. 'Cause how can you be grumpy, when the sun shines out your bum?



I'll try to find time to listen later, but resonances are an overload/spike in a particular frequency or frequencies, and a good way to diagnose them is with a realtime spectrum viewer so you can more easily pinpoint the problem frequency spikes.  Here is a free one, for example,


That lets you clearly see the spike's frequency. Then you can precisely EQ down the offending frequency.

Ideally, though, you try to record without getting those spikes in the first place. That means keeping an eye on the frequency of what you are recording so that different takes don't keep overlapping much in the same frequency range.  Again, the spectrum meter is real useful. I have one on running on my master bus all the time.

Hope that helps a bit.
The Circular Ruins / Lammergeyer / Nunc Stans


I have to deal with this kind of thing quite a lot. An ebow can create really peaky sounds, its the
nature of the beast.

You can experiment with turning the volume down on the guitar, using less gain on an over-driven
sound and (most critically) moving the ebow away from the hot spot.

As has been said, try to prevent the issue at source. As further processes can make things worse.
Yes, eq with a spectrum analyser of some kind will improve things, but its less than ideal with a
problematic recording.



Thanks for the replies guys, really appreciate it.

Here's a better example actually - this is basically a 20 second loop.

It's a bit quiet, but I like the sound of it. However, turn the volume up and it just starts to sound a bit heavy in the mids, just slightly unpleasant..

Okay, I've pretty much tried what's suggested - both at source and at the end of the chain. Trying to compress/EQ the output of the guitar before it goes anywhere, and then right at the end of the signal chain, by which time I suppose the damage has already been done.

I guess part of the issue is that i'm using two reverbs - one mono feeding the other stereo one, and both are around 8s tail. I've also tried EQ'ing the output of the first EQ but after a while you just start guessing and getting nowhere!

So I could try:
1) Work from the source - try getting the guitar sound as clear as possible and/or
2) EQ the reverb tails from one or both reverbs

Any other suggestions?

Thanks again!


Oh, and I have been trying to use SPAN but it's not always clear which are the problem frequencies...

Wayne Higgins

Nice stuff

Question 1:  Are you adding the reverb before or after recording?  (Are you playing with the reverb, or adding it later?)  From the words of David Lynch, you can always add echo, but you can't take it out.  Same with reverb.

Question 2:  If you are playing with the reverb, what are you using?  If you can adjust the "wet" amount, take it down.  If you can adjust the mix, take it down.  But primarily, if you can decrease the time the reverb is present (as in RT 60, I would start there).  If you are playing with the reverb on before recording, I would say try experimenting with lowering these amounts.

Question 3:  If you are adding the reverb later, what happens when you remove all of the reverb effects?

Haven't been able to listen to the 2nd one yet.  Rapidshare has a delay between downloads.

QuoteI guess part of the issue is that i'm using two reverbs - one mono feeding the other stereo one, and both are around 8s tail. I've also tried EQ'ing the output of the first EQ but after a while you just start guessing and getting nowhere!

From past posts on this board, there are quite a few who know more about EQing than I do, so I won't even go there.  If you are using an 8 second tail, that may be your problem.

One final question:  what is the diagram of your set-up?   I use guitar-filter-distortion-modulator-volume pedal-delay modeler (echos/loops)-dual processor (includes reverb)-recording device.  I've never used an e-bow.  I told a friend I would probably get really lost with one and go off the deep end or something.

Go there and check out "Idyll Idol Idle Ideal" and see if you like it.  The reverb is there when playing, but way down, and then a bit more added with Pantheon Reverb, but slight.  I do most things with a slight (of) hand.  It's the slow flange and slight reverb that gives it the chorus illusion (I think). :D
So, I'm a "Sr Member", huh?  In June it's SENIOR DISCOUNT TIME!!!

Wayne Higgins

So, I'm a "Sr Member", huh?  In June it's SENIOR DISCOUNT TIME!!!


Thanks for the comments, Wayne :)

The issue is that the reverb is part of the sound I'm searching for - if I reduce the tail length or 'wetness' of the reverb, it sounds totally different.
I am 80-90% of the way towards the sound I'm trying to get. If you check the second mp3 I posted, it sounds pretty good at lower volumes, but there's still a slightly annoying 'distortion' around 500-1000Hz which if I could just lower slightly I'd be happy. However, it seems to be quite a large band, and EQ'ing the whole thing just lowers the volume of the whole loop and doesn't really achieve anything.

I think I definitely need to try and catch the resonances earlier in the chain. My set-up is:

Guitar -> volume pedal -> audio interface -> Looper -> compressor -> guitar amp plugin -> mono reverb (8s) -> chorus->stereo reverb (8s)

or something like that, it varies a bit. The output of the mono reverb is the first part of the chain that is actually routed to the speakers...

I also have plonked compressors and EQ between the reverbs and at the end. Guess I just need to keep experimenting!



Yeah good point - I'm actually using a reverb plugin that seems to be discontinued for some reason. It has an amazing sound - I've not heard any other software reverb come close...


It would be interesting to try out a couple of PCM80s instead but can't quite afford it at the mo....  :)

I think there's a demo of that Soniformer so I'll give that a go. Cheers chap.


Try the 'lush universe' preset in R66 - that's the preset I always use and reminds me of my Quadraverb.

Not tried Ariesverb. I tried Aether after the amazing review in Computer Music but was a bit disappointed to be honest - didn't find it as rich as I was hoping, but maybe need to play with it more though.


Another example - it's a bit quiet, and a bit noisy (grrrr, bloody guitar) but I actually quite like this piece....