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Help me tame my out of control bass

Hey all,

Hoping to get some advice on how to tame what appear to be some pretty bad room modes. See my system here:
https://systems.audiogon.com/systems/8800

I’m in a bit of a pickle for a few reasons. First, my NY apartment is on the small side and requires me to set up on the long wall with the listening position against the opposite wall. On top of that I upgraded to my dream speakers, Egglestonworks Kivas. They sound amazing but they’re big and have a lot of low end reach. The combination of these two factors leads to the waterfall you see in my system - a pretty massive bump in low end, particularly at 40-44hz and from 60-70hz.

There’s also a huge bump at 120hz, but I don’t understand how that one is possible. I think that might be a measurement or microphone error - I don’t hear that at all and it doesn’t go away even when I EQ 120hz out completely, but maybe it’s a resonance?

Things I’ve tried so far, each with modest success:
- Plugging the ports gave me about a -5db reduction in the trouble spots (all measurements are with the port blocked)
- I don’t have a ton of placement flexibility but moving them back from their original position gained me about a -3dB reduction in bass
- I added a pair of 5.5” thick GIK bass traps, but they didn’t do much that I’m seeing in the measurements. Maybe a -1-2dB reduction, tops. They honestly helped more with the mids and highs.
- Convolution curve in Roon - this works the best, but doesn’t solve the problem for home theater or vinyl

I’m pretty stumped as to what else I can do. I think that the amount of bass traps needed to fix this is more than my marriage can withstand. I’m considering the PSI AVAA active bass traps, but only if I can do a home trial of them first to see if they’ll actually help - I worry this 8-10dB bump I’m seeing will be too much for even a pair of those. I could get a DIRAC processor from miniDSP and that would at least then work for all digital sources. Vinyl is mostly not a problem since this is so low and most of my vinyl is rock and jazz.

Any other ideas? Rolling tubes that have less bass? Are there any less expensive EQs with digital in and out that I could use as an alternative to the DIRAC for home theater only?
hudsonhawk
oldhvymec
5,101 posts
 
The 120 issue. I read Erik had said it may be AC. It that because 220-40 VAC. being on at the same time? Or some 220-40 VAC something being on? I’m not following, I’m a little foggy these days, the light is a little dimmer lets say..:-)

I don’t run anything at 220-40, except the AC and never when the stereo is on. Maybe that’s why I never see a serious spike like that.

I see it on the flame/graph, can you hear that? If it’s there you have to be able to hear it, right. Can the spike be so narrow you can’t hear it? I guess the answer is in the second graph, with no audible seen, proves you can’t hear it? I’m not understanding the bottom to top narrow line @ 120 (ish). I need the tech tofu!!!

Regards
rego
378 posts
 
Reposition L/R mains for best effect ... and you could use the online calculators (for convenience) to identify the room modes.
erik_squires
16,898 posts
 
The flame graph shows the 120 Hz is a constant, not related to the test signal. It could be mechanical, even a transformer humming, fluorescent ballast, or it could be coming through the speakers, but it is NOT related to the speaker response.
hudsonhawk OP
137 posts
 
The odd thing is that 120hz didn’t seem to be there when there’s no signal. This weekend I’ll do some more measuring, there’s been a lot of good hypotheses about what it could be. I’ll run a test tone at 60hz to see if it’s a harmonic, more mic’ing of the room with no signal playing to see if it’s environmental, and with different sources to make sure it’s not an artefact being produced by my DAC or integrated amp.

@rego placement is the correct way to solve this, unfortunately the speakers are quite large and the room allows limited movement of the listening position or the speakers themselves.

Good news is I got in touch with PSI and am in the process of arranging for an in-home trial of the AVAA C20, which could be a good, if expensive, solution to my troubles.

I’m also planning on a few other measurement trials this weekend with different placement of my bass traps, this thread’s given me a ton of ideas thank you all for your thoughtful responses.
erik_squires
16,898 posts
 
I wonder if you have a ground loop from your test signal source? 
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