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Ringing created by tight Q cut Equalizer Plugins
Old 12th September 2011
  #1
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Ringing created by tight Q cut

I heard something the other day that I've never heard before and was wondering if anyone would have an explanation of why or how this could happen.

Take a song with an ugly resonance in the 140hz range. Use a Weiss EQ1 to notch out the frequency & harmonic. Very tight Q.

When I play the section in question with the EQ in and stop playback, there is a resonant ring that happens. Almost sounds like tapping a finger on a 50 gallon drum. Take the EQ out and it goes away.

I thought there may be something in the room ringing, but with monitors off and headphones on, it still happened. If I widen the Q, the resonance goes away. Again...this is cutting, not boosting. Digital EQ

Any takers to explain this phenomenon?
Old 12th September 2011
  #2
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24-96 Mastering's Avatar
Quote:
Originally Posted by Rick Sanchez View Post
I heard something the other day that I've never heard before and was wondering if anyone would have an explanation of why or how this could happen.

Take a song with an ugly resonance in the 140hz range. Use a Weiss EQ1 to notch out the frequency & harmonic. Very tight Q.

When I play the section in question with the EQ in and stop playback, there is a resonant ring that happens. Almost sounds like tapping a finger on a 50 gallon drum. Take the EQ out and it goes away.

I thought there may be something in the room ringing, but with monitors off and headphones on, it still happened. If I widen the Q, the resonance goes away. Again...this is cutting, not boosting. Digital EQ

Any takers to explain this phenomenon?
All EQ rings, necessarily, by working principle. I'm sure someone smarter than me can explain the physical necessity for this elegantly.

In practice, what's relevant is that the tighter the Q, the more easily audible the ringing, and the lower the frequency, the longer it is. Obviously, it's mostly audible on percussive instruments/sounds, where there is nothing to (temporally) mask it.

Minimum phase EQ has post ringing only, linear phase EQ has pre and post ringing... i.e. ringing before the signal, which will hardly be masked, so be careful with linear phase EQ on percussive downbeats at the beginning of a track or after a breakdown.

Also see:
Ringing artifacts - Wikipedia, the free encyclopedia
Pre-echo - Wikipedia, the free encyclopedia
Old 12th September 2011
  #3
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William Bowden's Avatar
 

Verified Member
Quote:
Originally Posted by Rick Sanchez View Post
When I play the section in question with the EQ in and stop playback, there is a resonant ring that happens. Almost sounds like tapping a finger on a 50 gallon drum. Take the EQ out and it goes away.
So the ring continues after you stop playback? Any tube gear in the audio path?

King Willy
Old 12th September 2011
  #4
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Casey's Avatar
 

I believe the Weiss is a linear phase (or AKA FIR) filter. The very low frequency and tight cut that you have dialed in requires a very long filter in terms of time. The shape of the filter is similar to a sine wave.

So, what you are doing is convolving your input with a short tone. Just for fun, (and root cause if you are so inclined), you can hear this tone in isolation and in it's entirety by running a single sample impulse through the filter.



-Casey
Old 12th September 2011
  #5
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Quote:
Originally Posted by William Bowden View Post
So the ring continues after you stop playback? Any tube gear in the audio path?

King Willy
Nope..no tube gear in the chain. I've often heard ringing when boosting, but never like this when cutting. The extremity of it was what was so surprising. The ring would last maybe a third of a second after stopping playback, which is why I immediately thought it was something in the room resonating until I put on the headphones.
Old 16th September 2011
  #6
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William Bowden's Avatar
 

Verified Member
Quote:
Originally Posted by Rick Sanchez View Post
Nope..no tube gear in the chain. I've often heard ringing when boosting, but never like this when cutting. The extremity of it was what was so surprising. The ring would last maybe a third of a second after stopping playback, which is why I immediately thought it was something in the room resonating until I put on the headphones.
If that's the case, then you should be able to record the ringing, ie stop playback but keep recording then have a bit of a look at what you've got. You can only do this if you have a playback DAW and a record DAW though, but it's worth a shot don't you think?

The other thing I'd try is turning the power to the Weiss off and on again. My DS-1 has been known to make some pretty strange noises every so often, usually when the sample rate has been changed a few times over the course of a few days.

King Willy
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