# How to find resonant frequency using REW



## Arizona Dan (Mar 8, 2008)

Hi

I downloaded REW a few weeks ago and have a question. This is probably a dumb question, but I will ask anyway.

Certain voices and stringed instruments seam to hit a resonance in my room. Probably a combination of loudspeaker issues and room mode issues. How do I use REW to identify the frequency causing the issue? 

Thanks for your help.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Since you note the problem is with voices and stringed instruments, I'm guessing what you're hearing is in the upper frequencies (i.e., above the subwoofer range). Depending on exactly where it is, it may be with the speakers themselves rather than your room. REW can tell you where the problem is; just take a full-range reading. The Radio Shack meter is only good to about 7 kHz, but the problem will more than likely be below that point.

Regards,
Wayne


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## avaserfi (Jul 5, 2007)

If the resonant frequency is within the room REW should be able to help you find the issue, but that won't be the case with cabinet resonance. Cabinet resonance is not measurable via typical methods of measurement, but rather, in an far field anechoic situation using impulse response tones at varying angles then a waterfall plot would need be derived for cabinet resonance to show up on a plot.

A more simple method would be using an accelerometer attached to various point on the cabinet and then averaging the responses. It is however fairly likely that your speakers do have resonant cabinets as most DIY and commercial speakers have fairly resonant cabinets.


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## Arizona Dan (Mar 8, 2008)

Thanks for the reply. 

Question - If the resonance is heard as fairly large gain in volume during the resonance, would it most likely be the room - or can a loudspeaker enclosure have that loud of a resonance? The speakers in question are Vandersteen 3A's. I just got a pair of Klipschorn's, so I am experimenting with them also.

Dan


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## WmAx (Jan 26, 2008)

Arizona Dan said:


> Thanks for the reply.
> 
> Question - If the resonance is heard as fairly large gain in volume during the resonance, would it most likely be the room - or can a loudspeaker enclosure have that loud of a resonance?
> Dan


It can be a double-whammy.  The more reverberant/resonant the room, the more audible cabinet resonances become - as is shown by the current standing perceptual research.

-Chris


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## Wayne A. Pflughaupt (Apr 13, 2006)

Arizona Dan said:


> Question - If the resonance is heard as fairly large gain in volume during the resonance, would it most likely be the room - or can a loudspeaker enclosure have that loud of a resonance?


The "rule of thumb" is that above ~500 Hz the speakers dominate, and below that point room influences becomes the primary factor. REW will show either one...

Regards,
Wayne


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## jerome (Apr 24, 2007)

Agree with Wayne on this one. Take some full range measurements with both front speakers and separate measurements (with only one speaker at a time) if you feel like it might help.


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## WmAx (Jan 26, 2008)

Wayne A. Pflughaupt said:


> The "rule of thumb" is that above ~500 Hz the speakers dominate, and below that point room influences becomes the primary factor. REW will show either one...
> 
> Regards,
> Wayne


How will REW demonstrate cabinet resonances, in mid/far field, as differentiated clearly from room effect(s)?

-Chris


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## Wayne A. Pflughaupt (Apr 13, 2006)

REW doesn't know cabinet resonances from your mamma's pancakes. :laugh: 

What it _will_ show is hot spots in response, if there are any. It's up to us to figure out what's causing them. 

Regards,
Wayne


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