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Help eliminating peaky bass


csshakka

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Like the topic says, how do you go about eliminating a stubborn peaky bass output? The frequency is near the 50hz area. With a Pioneer 80prs, I thought hey, 16 band eq, crank 50hz down until it sounds good. The issue is that this frequency area (50+/- 5hz) tends to vary how peaky it is compared to everything else depending on volume.

My setup:

Polk 6501s up front, Polk 651s in rear on rockford fosgate r300-4

2x alpine type r 12s in 1.65 cu ft/ea @ 33hz on sundown saz-1200d

I've tried using an RTA program with a Dayton emm6 mic and I'll get it balanced, but as soon as the volume changes, it goes out of whack. Amp gains are set with SMD dd-1 @ -7.5 tones. There was a post somewhere saying peaky sub response above half volume could be due to lack of power. 600w/ea type r is a little lower, could this be part of the problem? I'm a bit lost with things to try, any suggestions?

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After searching around, some ideas come to mind. Would polyfil be worth trying? Hopefully drop tuning a bit to even out the peak. Also, do type r's tend to be more peaky on 600W vs 1000W? I'm pretty sure cabin gain might be part of the problem, but that isn't going to change. Or would it be worth it to consider selling the type r's and getting like two SA-12's? Thoughts?

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Polyfill may help, the box may be a bit small for those subs. Another thing you can try is moving it around in your trunk. Also, where are your LPF (subs) and HPF (mids), and what slopes?

"Clipping" is the biggest forum boner now. It's like witchcraft... it automatically explains just about everything people don't understand.

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Tuning on your box may be off. what are the measurements ?

CURRENT SYSTEM:

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    2. Isolated DC Power 270 SP - Charging @ 16.8v
  • Batteries: (2) XS D1400s
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  • Subwoofers: 2 RE MT 15s /PSI dual .7ohm recones
  • Subwoofer Enclosure: 9.1cubes @ 32hz - brutal.
  • Mids & Highs Amp: CT125.4
  • Active Components:
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    • Highs - 3 RE XXX tweeters per side(A pillar)
  • Noise Control: Damplifier Pro all over the cab.

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eq the peaks lower ?

Tried that. The problem is that it seems to vary based on volume. Example, 55/62 volume may have -3 on the 50hz eq band and be fine, but at 40/62 volume, that 50hz note masks the mids and has to be adjusted to like -5/-6.

Polyfill may help, the box may be a bit small for those subs. Another thing you can try is moving it around in your trunk. Also, where are your LPF (subs) and HPF (mids), and what slopes?

Polyfil it is then. The box can't move much...it's squeezed in there pretty good lol. Dimensions are pretty much maxed out for the space except height wise, but experimenting before with only one type r in a similar box, positioning didn't seem to help much. My LPF and HPF filters are set at 100hz @ 12 db slopes.

EDIT: how much polyfil do you put in? Like medium firmness after you pack it in? Less? More?

Tuning on your box may be off. what are the measurements ?

The box should be pretty close. After building, I remeasured the internal volumes of each chamber and they were really close to the design. I think punching the numbers back in to a calculator gave 33.4hz tuning or around there. I can get the dimensions if you think it's worth it though.
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If it's varying, seems like either an enclosure or an environment issue. If you can't move it around, then you should be able to turn it to the left or right, maybe face subs up, or at the very least spin it all the way around. You should get different readings. Also, in a different test, put the mic right near the port, that way you can measure just the enclosure.

"Clipping" is the biggest forum boner now. It's like witchcraft... it automatically explains just about everything people don't understand.

My build log: http://www.stevemeadedesigns.com/board/topic/200295-gckless-2011-chevrolet-impala/

High resolution photos: Gilbert Kless Photography

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If it's varying, seems like either an enclosure or an environment issue. If you can't move it around, then you should be able to turn it to the left or right, maybe face subs up, or at the very least spin it all the way around. You should get different readings. Also, in a different test, put the mic right near the port, that way you can measure just the enclosure.

That's a good idea. After work I'll mute the mids/high and take measurements by the port and then again up front. That should give some insight of enclosure vs. environment.

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