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stupid m0nkey 1st April 2004 06:29 PM

parametric equalizers
is the 'Q' on all parametric equalizers a set amount (ie. a 'Q' of .5 is 2 octaves) or does each manufacturer set their own standards for 'Q'? i specifically am wondering about my Alpine 3402 (car audio)

haldor 2nd April 2004 03:19 AM

Q = 1 means the filter has a bandwidth of 1 octave. This is standard as far as I have ever seen

stupid m0nkey 2nd April 2004 03:23 AM

so then a Q of 10 would mean 1/10 of an octave?

FLZapped 2nd April 2004 12:52 PM

Yes, a Q of 10 means the filter's -3dB bandwidth points(half power) will be 0.1 octave. It's a simple mathmatical inversion.


macboy 2nd April 2004 01:15 PM

Q is defined as the bandwidth divided by the center frequency, both in Hz of course. So an EQ with a bandwidth of 5000 Hz centered at 10000 Hz has a Q of 0.5.

The problem is that "bandwidth" is not strictly defined. That is where the difference between manufacturers come. One common definition is where the EQ has half the boost or cut as at the center frequency.

For more information than you could ever want, try reading up on Constant-Q EQ's and Exposing Equalizer Mythology and Operator Adjustable Equalizers at Rane Audio's website.

JensRasmussen 26th April 2004 08:41 PM

2 Attachment(s)
I think it's like this


Slab 15th February 2005 06:56 AM

I'm no expert but let me try to understand the question.
"Is the Q on all parametrics the same?"
I thought "parametric" meant adjustable parameter. Every equalizer has three basic parameters: Gain, Frequency, Bandwidth (Q). Every parametric I've seen had adjustable gain and freq and Q. Usually a Q from about .5 oct to 2 oct. The mathematical relationships between Q and freq can be seen in the other forum responses. I am not familiar with the Alpine EQ but if the Q is not adjustable it has very limited capability.

Enzo 16th February 2005 04:49 AM

Oh, I get it. Not all parametrics have adjustable Q, and if yours doesn't, then you want to know what they made it, yes? That would be up to them and what they wanted to achieve. There would be no particular standard, though it might well be that more than one maker might settle upon a similar figure as the best overall compromise.

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