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Why would a limiter only affect the lower part of the wave?
Old 1 week ago
  #1
Why would a limiter only affect the lower part of the wave?

I've been experimenting with overdrive and limiting on a sound file with outboard gear, and for some reason the affect is mostly being applied to the lower part of the wave. So the top part of the audio has all the peaks mostly untouched while the lower part is being limited / clipped.

Does anyone know what could cause this?
Old 1 week ago
  #2
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Drumsound's Avatar
Is there a lot of low frequency information in said wave?
Old 1 week ago
  #3
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allstar's Avatar
 

A DC offset could cause this I imagine.
Old 1 week ago
  #4
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crosscutred's Avatar
What do you mean by "wave"?

Are you looking at it on a scope?
Is it the representation of your audio in a DAW?
What is that picture of your audio supposed to represent?
Which DAW?
Is it standard across all DAWs?

I think these are the questions you need answers for.
Old 1 week ago
  #5
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ruffrecords's Avatar
This is quite a common effect in single ended gain stages. I suspect somewhere in your signal chain is a device containing a single ended stage which is causing this.

Cheers

Ian
Old 1 week ago
  #6
Here is a pict of the waveform, the top one is limited:
Old 1 week ago
  #7
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Quote:
Originally Posted by FlyingMusician View Post
Here is a pict of the waveform, the top one is limited:
OK... so I see here in the top wave lots of low mid and low info, and transients being smashed to pieces. Do you have attack and release controls on this processor? I would back off (((make the attack time slower))) on the attack time and let those transients develop more before the processor stomps on them. Is this a guitar waveform?
Old 1 week ago
  #8
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ruffrecords's Avatar
Those waveforms look like a seriously over-driven limiter to me. How much gain reduction are you getting?

Cheers

Ian
Old 1 week ago
  #9
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Quote:
Originally Posted by FlyingMusician View Post
I've been experimenting with overdrive and limiting on a sound file with outboard gear, and for some reason the affect is mostly being applied to the lower part of the wave. So the top part of the audio has all the peaks mostly untouched while the lower part is being limited / clipped.

Does anyone know what could cause this?
[Then..
Quote:
Here is a pict of the waveform, the top one is limited
Hi. I singed in here as I wanted to know (learn) where this was going.
Now with the pictures (top one being the one in question?), it looks to me the tops are limited ('touched), and the lower parts look to me simply to be the result of make-up gain (?
Old 1 week ago
  #10
Yes, I remembered it differently when I first posted then took a pict of the wave form and it shows the top of the audio is being compressed.

I'm basically overdriving this signal with a transformer but what I don't understand is why is this just crushing the top of the wave?

The signal was being routed through many parts of my console as well. I've since been working on another project and will need to revisit this. It's possible when I set things up again this problem will be gone, but I'm mostly just curious how this "could" happen. I understand about the DC offset, but not sure electronically speaking how a DC offset could occur in the studio.
Old 1 week ago
  #11
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ruffrecords's Avatar
It would help if you could describe the complete signal chain. Might give us some clues.

Cheers

Ian
Old 1 week ago
  #12
OK I've boiled this down to overdriving the transformers. This is a hand built box using some 1960's transformers so it may be part of it's inherent behavior or these may be slightly faulty.
Old 1 week ago
  #13
Lives for gear
Something is clipping, so the item being over driven does not take that very gently.
Old 1 week ago
  #14
Quote:
Originally Posted by FlyingMusician View Post
OK I've boiled this down to overdriving the transformers. This is a hand built box using some 1960's transformers so it may be part of it's inherent behavior or these may be slightly faulty.
DC bias on the transformers will do this. Normally there should be blocking capacitors; check whether they are missing or leaky.
Old 1 week ago
  #15
Quote:
Originally Posted by David Rick View Post
DC bias on the transformers will do this. Normally there should be blocking capacitors; check whether they are missing or leaky.
Thanks David
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