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Low frequency issues and measurements

Willem

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I have two suggestions:
1 integrate your subwoofer properly, i.e. find the best location, correct level and correct low pass filter frequency. Use measurements for this.
2 once that is done, try to equalize the combined response with an REW curve, but avoid equalizing above about 200 or 300 Hz. You can use a computer as a source for the experiment by installing the free equalizer APO software on the PC and upload the REW correction curve into the EQ APO. Evaluate the result, not just for the main listenng position but also elsewhere. If reducing dips and obtaining a smooth reponse over a wider area are seriously unsuccessful, get a sesond sub.
 

ppataki

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@atoprak

Did some further simulations:

EQ-d your main speakers (nosub) to 60dB and used a steep (LR8) highpass filter at 80Hz:

1657554494268.png


Then did the same with your sub but with a lowpass filter:

1657554546442.png


Then simulated the sum of them:

1657554573231.png


The dip at the crossover region can be fixed by inverting the phase of your subwoofer and summing them again:

1657554616641.png



This is what your final curve will look like, sub integrated

Note that I have not done any phase alignment, etc. - maybe @ernestcarl could kindly chime in here, he is an expert of that

All measurements (incl. simulations) can be found here:
 

Willem

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And this is a rather nice result, even if the equalization will only be effective in the primary listening position, and more so the higher the frequency (hence my advice against equalizing above about 200 or 300 Hz).
 

ernestcarl

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I don't feel comfortable equalizing in detail a system without enough data so the ff. is only going to be very generalized. I retained the LR8 HP-LP filters applied by @ppataki but overlapped the xo more.

1657595604046.png


Either no delay or a mere 1 ms delay to the subwoofer signal is enough. HOWEVER, all of this needs to be verified with actual real measurements since the acoustic timing in the original measurements may be off.

1657595609279.png


Below 20 Hz, the information is cut off so I didn't apply any filters.

1657595615750.png 1657595619956.png
 
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