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post #1 of 4 Old 06-27-2019, 09:04 PM - Thread Starter
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Below 30hz issues

So, one of my UXL's was damaged (small child involved). I replaced it with a version 1 SI18. Performed some measurements today and I have lost alot below 30hz.

I corner load (4 corners used). Black is two pa460's opposite corners one front-one back of room along with SI and UXL in the other corners. Purple is pa460's moved to corners on the same side of the room and SI/UXL in the corners on the other side. Measurements were subs combined with center (DIYSG Fusion 8).

I can't figure why 30hz down through 20hz is dropping so quickly. These are all ported subs. pa460's high passed @ 40hz and the 9.5 cuft SI/UXL high passed @ 20hz and low passed @ 70hz in the Inuke dsp.

Any thoughts?
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post #2 of 4 Old 06-28-2019, 08:41 AM
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post #3 of 4 Old 06-28-2019, 05:30 PM
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Measure each sub individually with the rest of the speakers off, both nearfield and at the seat.
For the nearfield do only a few inches from the cone middle (making sure not to clip the mic, and not near the port wind).

Then compare.
As you sum pairs, ensure you are summing correctly across the whole bandwidth, or at least not making the <30hz worse.

It's possible that the different driver parameters have changed the performance characteristics of the subwoofer, and/or messed with the phase coherence. Driver sensitivities and motor strengths etc.

It's also possibly a room-null.
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post #4 of 4 Old 06-30-2019, 02:11 PM - Thread Starter
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Quote:
Originally Posted by BassThatHz View Post
Measure each sub individually with the rest of the speakers off, both nearfield and at the seat.
For the nearfield do only a few inches from the cone middle (making sure not to clip the mic, and not near the port wind).

Then compare.
As you sum pairs, ensure you are summing correctly across the whole bandwidth, or at least not making the <30hz worse.

It's possible that the different driver parameters have changed the performance characteristics of the subwoofer, and/or messed with the phase coherence. Driver sensitivities and motor strengths etc.

It's also possibly a room-null.
Each sub measured individually, full range w/ all peq, hpf, lpf disengaged. I found an issue with the in-box connection of the SI. Not even sure it was measuring every time as the connection was loose.

Here are the indiv. measurements at MLP (pa460's separate then combined) (SI, UXL separate then combined). The final measurement was taken (all subs + center) after HPF's, LPF's and some adjustments to delay on the SI and UXL.

Watcha think?
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