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-   -   Primitive harmonic distortion test of Dayton DVC 8" (http://www.diyaudio.com/forums/subwoofers/96433-primitive-harmonic-distortion-test-dayton-dvc-8-a.html)

arjscott 16th February 2007 08:40 AM

Primitive harmonic distortion test of Dayton DVC 8"
 
2 Attachment(s)
Hi all,

I'm seeking opinions on the results below. To my relatively untrained eyes this looks like 3rd order harmonic distortion 10 dB down from the fundamental frequency. And also 5th order 20 dB down, 7th order 30 dB down.

The first result shows the measured response playing a 50Hz sinewave, and the second is 100Hz. Obviously all I'm doing here is using TrueRTA. Is this a valid test?

I have to admit I have been using it for a few weeks in a temporary enclosure, and at usual low listening volumes this distortion is not obvious to me.

I suppose I can't complain about the performance of a US $23 driver, but I was expecting the distortion to be a little lower than this.

Andrew.

arjscott 16th February 2007 08:41 AM

2 Attachment(s)
Second pic

Ron E 19th February 2007 12:06 AM

What is the drive level?

-10dB is ~30% distortion

That is pretty high for 100Hz - you may want to make sure you are not overdriving your microphone or clipping the input signal from having the mic gain too loud. Experiment with mic gain settings, if turning down the gain gets you lower distortion you are overloading your inputs.

arjscott 19th February 2007 05:16 AM

Hi Ron,

Thanks for your response. You were right. I had the mic a little closer than normal to the speaker, and I didn't think to check this.

What an idiot... Well I'm pleased the driver's distortion is nowhere near this level.

Andrew.

shrub0 19th September 2012 06:10 PM

Would you mind sharing the distortion plots of this driver once you calibrated the microphone.

Thanks

tvrgeek 19th September 2012 07:33 PM

When talking subs, the power level is quite important to know too. Subs tend to get pushed pretty far and distortion will vary. 1W distortion will not be the same as 30W. I would hope it remains under 10%

Brian Steele 20th September 2012 12:27 AM

TruRTA is a great product. For distortion measurements though, there are other tools available. Have a look at HolmImpulse (free) for example.


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