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
Mini-DSP. 
That’s what I:d do.
Sounds like your only option.

It is a calibrated mic (miniDSP uMik-1).

I just don’t have any other explanation for that spike at 120hz, which is present even when I EQ 120hz to zero. I’m at a complete loss what that could be.
Looks like pretty normal room response to me. Find me a room that does not have humps like that. Good luck! All that happened, you finally got some good speakers with good bass. Now you want to get rid of a lot of what is great about your speakers. Go figure.

Those humps are there in almost every room for the simple reason the room is smaller than the bass waves are long. So they all reinforce and cancel. Your real problem looking at your charts is not the humps but the suckouts. I notice you're not all that concerned with those. Not at all. Yet they are by far the bigger problem. Funny.

The other thing I notice, if that is where you are sitting, right next to the wall, well no wonder. Bass response is not just the speakers and where they are. It is equally the listener and where they are. Anywhere near a wall is going to be huge bass reinforcement. Move even a foot or two away from the wall and into the room, this alone will make a huge improvement.
Definitely aware of the back wall reinforcement, however the room isn’t big enough to allow moving the couch forward more than a few inches. I’m also aware that probably limits how much improvement I can realistically make here.

Don’t get me wrong, I’m worried about the suck outs as well - it’s funny, I generated a tone at 55hz after noticing that cavernous drop on the graph and confirmed it’s completely missing in the listening position, and reappears as soon as you move around the room. Room modes are funny things.

That said the humps are the more glaring problem since they have such long decay time they end up sounding super muddy and boomy.
I have a feeling the spike at 120 is a crossover issue, 60-70 is normally an 8 foot ceiling, 40-50 (and if you had 9 foot ceilings) is the room size. So reflection point over your head and in front of you. Pull the speakers out from the walls, if only for listening. The suck out is REAL important.
WHY?, you’ll enjoy the un bloated bass, because you’ll volume DOWN.

You filled in the missing parts, you’ll see, MC was right on. Take care of the suck out and the bass will clean up.. Bass traps at 12" to 48" in all 4 corners, Not higher, not lower.. Both front and rear walls, dead center, do something, Drapes, kill the returning waves a bit...

EQ the rest. I use full blown DSP for bass management, nothing else 300 hz and below. PEQ, GEQ, slopes, threshold, phase...everything..
Above 300 hz all passive with high quality parts..

The slow decay rates are because the room is WAY to lively.. That is also why you have all the combing (dips, and actual valleys..)

Ricochet biscuit, comes to mind..:-)

Regards
Hi,
Just moved out of a very similar situation.

You have done a lot and are pretty much thinking the right way.  Remember that though a bass trap may only change your FR a little, it will help EQ work much better. 

Try miking your speakers like 1' away and see if your 120 Hz bump is still there.  If so, it may be a microphone artifact.

Personally I went overboard and used GIK soffit traps and have not really regretted it except for the space they take up.
@hudsonhawk, welcome to the world of impulse measurement. It is not just the troughs but the peaks also. By 20 Hz you have lost almost 25 dB.
Sonically troughs exaggerate the peaks! You are hearing 40 and 50 Hz more because 38 and 47 Hz are missing. You can not just cut the peaks. You have to boost the troughs also. I assume your listening position is forced up against the opposite wall which is going to make this worse. Take measurements elsewhere in the room. As you have noticed bass traps do not work. They are acting as diffusers of higher frequencies. I get castrated for this opinion all the time. They are a complete waste of money. Made the same mistake myself. Check out my system page and you will see this is the voice of experience talking. Many systems are worse than yours! You were headed in the right direction but forget about Dirac. Check out the DEQX Premate, the Anthem STR preamp and finally the Trinnov Amethyst. All of these units will totally fix your problem. If my TacT were to go down I would get the Amethyst. The Amethyst also has a built in phono section. All three units are much more comprehensive than a "mini DSP."  You have a nice system it deserves better. It will sound so much better you will wind up like me digitizing your turntable. You have a beautiful turntable. Nice choice, fully suspended, great tonearm. Please get it a dust cover!
Try miking your speakers like 1' away and see if your 120 Hz bump is still there. If so, it may be a microphone artifact
@erik_squires Yep, still there even mic’d directly in front of the speaker. So to oldhvymec‘s point it could be a crossover issue or a mic artefact like you said. Unlike the other ringing in the waterfall I’m not hearing it, so I’m inclined to think it’s a mic artefact. Would love to do the same with bass traps but I think I’m already pushing my wife’s tolerance for panels.

@oldhvymec to your point, pulling them out does reduce the bass suck, but makes the peaks greater and makes the midrange less flat. Here’s an SPL graph of them pulled out (red) vs their current position closer to the wall (orange): https://www.dropbox.com/s/4rd8y9uy7jw12lb/Screen%20Shot%202021-02-22%20at%2010.06.16%20AM.png?dl=0

I have 10 GIK panels in the room right now, in retrospect the mistake I made was getting too many 2” panels and not doing enough bass traps or ceiling panels. They’re crazy expensive but one of the things that appeals to me about the PSI AVAA is that they’re easily moved and don’t require a ton of work to install. 

The tough thing about renting is not wanting to overinvest in a solution for your current place, in fact our lease is up in a few months and we’re currently considering moving. I’m tempted to just to get a better room for my stereo, where I won’t need to have the LP be against a wall...

Great suggestions all, thanks for the thoughts.
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I just looked at your waterfall.  That's not your speakers!

That solid green line at 120 is background noise. More likely either your equipment or something like an AC running.

Try this.  Measure with no signal.  Then turn all your electronics off.  Repeat.
Over the past 15 years, I have moved my system through 4 NYC apartments, so I feel your pain.

In one of my places, I experienced a very similar situation to what you describe.  I tried everything I could - moving the system, moving the listening position, installing bass traps, etc. 

In the end, the only thing that effectively cured my problem in that space was a DSPeaker-Anti-Mode 2.0 Dual Core.  I felt I might be trading off just a bit of magic having it in the signal chain, but the benefits far outweighed whatever it might have been taking away.
Wow, you do have a MB and low mids issue. 250hz WAY low. Can you hear voices clearly?

250hz low
1.5mhz low
2.5mhz low
7.5mhz GONE
The top is gone 8K and up is a down hill spiral. The orange line is against the wall? How the heck do you EQ that? You don’t, this is follow the bouncing ball. Man oh man.. Curtains, and you can take them with you..

I learned that a LONG time ago. Heavy curtains are your best friend..
Wall acoustic treatment, mids and highs. The bass I’d DSP and PEQ the suck out / combing in the mids and highs.. OVER your head and in front of your feet.. The side walls are the short walls.
They aren’t that short are they? LOL

That’s why the bass is bloated, mids, so so, but the 8K and up, that is a real problem for me.. I use ribbons and planars. I refuse to give up anything from 300hz -19k. Bass is always "too much", distribution is the issue too. I never could get great results with 60hz < in the same box, just can’t work.. I quit trying 30 years ago.. Different boxs for ALL the bass.

SERVO bass unit (s). That would work for the bass I bet..
I hate saying this, 130hz and down.. Normally 30-50hz and down.
My set up is different.. That 250hz suck out is pretty nasty though..
VOICES.. Bass Bassoon, low clarinets, Lena Horn LOL..

I don’t know OP, I’m just thinkin’ out loud..

Set up Kitty corner.. Read on Decware’s site about that.. pretty interesting read..

Sure a nice setup though..

Time to feed the Chickens. NY. Berrrrr!!! :-)

Stay warm...

Regards
@oldhvymec You know it’s funny, I didn’t think I had a problem with mids until I moved them into the current position (the orange line) and you can see that those deep troughs in the MB region improved significantly and it was like lifting a veil.

Agreed on curtains, the other problem with that room is that it’s asymmetrical so you have the windows on the left and then an open kitchen on the right. Maybe I need to get out of this nightmare room and move...
Where was the mic when you took that  measurement? General rule of thumb below approx 500hz it's the room above it's the speakers. Put the mic 1 meter in front of each speaker with it pointing between the tweeter and midrange see what you get. For anyone who thinks that's a normal looking FR I never want to hear your speakers. 
The orange looks better than the red those two big nulls at 55hz and 95hz are probably vertical,  floor or ceiling bounce or both.
@djones51 the mic was in the listening position. Given the untreated ceiling and windows on the left it’s safe to assume everything you’re seeing is the room. I can take a measurement directly in front of the speakers tonight or tomorrow, when I’ve done that it’s significantly flatter.
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GIK Acoustic foam panels do nothing for under 100Hz.  I know, I have owned them.  You have the same frequency issues as I do.  120 is a harmonic of the 60 hz bump.  

I put my money on the line and got some Diaphragmatic absorbers from Accoustic Fields.  I spent $5k and now the 40-50 bumb and 80-100 bump is now more flat and the room correction now can do its job.
The cat is there because it knows better than anyone where the good sound is, and has its priorities straight. All the OP has to do is convince the cat to swap places. I recommend gloves and a long sleeve shirt.
Crossover your speakers over at 200hz with 4 subwoofers. Do a dry run with 2 subs. Position the subs in the room for best measurements. 


@jimofmaine it never occurred to me until I started getting into measurement and understanding room modes that a reason to get subs is to have more flexibility in placement of where the bass is being generated.

@millercarbon she absolutely had her priorities straight and there was no way I would have ever convinced her to swap places. Sadly she passed away recently but she lived a long life and enjoyed my hobby a lot as it gave her lots of lap time, although like many from her generation she preferred digital to analog (because I never had to get up to change the record).
@oldhvymec ha, don’t worry the mic is at my head position. You’ve definitely got me thinking though of some creative ways to absorb the boundary issues on the left side where the windows are. On the right speaker because it’s an open room there’s no boundary issues there. 
@millercarbon

Save some insults and puffery for the rest of us.
erik_squires10,600 posts02-22-2021 10:33amI just looked at your waterfall. That's not your speakers!

That solid green line at 120 is background noise. More likely either your equipment or something like an AC running.



Bang on erik. It is pretty evident in the waterfall where the 120Hz does not decay.  Most 60Hz noise presents as 120Hz due to rectification. It is likely electrical noise.



Going to guess your main room is about 8m * 5m with 3m ceilings?

Then I am going to guess there is a wide hallway or extension off the main room?

8m, 5m, 3m are your 60, 110, and 180Hz approx peaks, then with a range of harmonics off those sizes.

The 45Hz is typically too low for a typical sized apartment, especially in NY and you said it is small? That leads me to believe there is a hallway / extension off the main room creating the 45Hz node and the suck-out just above it.
@audio2design you’re 100% correct. The right speaker doesn’t have a boundary wall next to it, there’s a counter and a kitchen and a hallway going to our office / entryway.

Incredibly impressive deduction.
mic at chin level approximate ear ht. sorry for the loss of your cat.

good on ya for posting the waterfall, this puts you many wandering light years ahead of the resident agon egotist.

Since you have already got panels and are not a flat earther only analog zealot, go the DSP route, just be aware with your ears that close to the mode aka the wall, results might not change that much....borrow one if possible...


I'm curious what the owners manual says about recommended position?

Three ports to deal with on the back sounds like a difficult combination to satisfy room effects.

What are the dimensions of the room? (for modelling)

I also would look for a 60 hz noise as it usually strongest at 60 x 2 = 120 hz. 
also, you might download the excellent and free Vandertones test and music files. the test tones are based on typical room modes....which are not always octave based ( duh, but a brilliant observation and more importantly implementation...like those are Vandersteens EQ centers )...and they include an excellent scaling acoustic bass solo that sails right thru and past 120 hz....

So like the legendary Max Townsend said: “ listen and measure “....
@tomeh45 there’s no manual for the Kivas, but I did talk to Jim at Egglestonworks and he not only had some tips for me, he was kind enough to cut some port plugs for me for the slot loaded bass port. For the transmission line ports, they’re pretty heavily diffused internally so they aren’t super loud, but just to reduce interactions further I have the GIK bass traps hung behind them so they are absorbing anything from them.

Audio2design pretty much nailed the layout, but here’s the floorplan in case you’re curious about the exact dimensions. Ceilings are 8 foot:
https://www.dropbox.com/s/nu53jkfvabh6bs9/Photo%20Feb%2022%2C%2011%2028%2019%20PM.jpg?dl=0
This may be impractical for you, but if you can afford it, try changing to a pair of MAGNEPAN 3.7's.

I'm quite certain that not only will you regain control of bass reproduction but will also reap other huge sonic benefits. Contact MAGNEPAN. I'm sure an engineer can make more detailed suggestions. If you can't afford the 3.7's there are a couple of less expensive models that will also provide a controlled audio spectrum, and still provide a heaping portion of the MAGNEPAN magic.
Saying bass traps don’t work is false. Get the right traps for the frequencies you want to deal with. 2” traps won’t do squat for bass, I use asc 16” tube traps as well as gik monster bass traps which both work. As for adding many panels and curtains in your room, you have to start worrying about an over damped room, which will kill the dynamics and your system, your system will sound dull
I didn’t say bass traps don’t work, my two bass traps are 5” thick. I didn’t see much measurable difference but i suspect I would need several more of them to get there, which as I said I don’t think the missus would allow.
Magnepans don't magically solve bass nodes unfortunately, however, adding a couple more subwoofers, some electronics for integration, and playing with speaker placement may.  That may get your lowest nodes under control, and then you can work on the higher ones. If the misses is into decoration, involve her in the selection process for acoustic treatment.
I am in a similar situation with Dunlavy’s in a too small of a room and I built 3 -10” broadband absorbers and have them spaced off of the rear wall about 6” -directly behind MLP and it has worked wonders!
Visit the forum called “gear sluts” 
Tons of really smart acoustics cats over there.
I have learned quit a bit there....
good luck
+1 on gearslutz, you will find far more acoustics experience there.
The cat found the sweet spot.

Dang, I just saw the millercarbon already pointed this out.
Have you tried to decouple the speakers from the floor by using some type of stone or block under them i have used these many times with carpet padding on top of them to remove any unwanted excessive bass resonances on wood and they work miracles for little to no money.
@speakermaster Great question and a detail I forgot to mention is that i did decouple the speakers by adding Isoacoustics Gaia feet to the speakers. It didn’t make as big of a difference for the bass as I was hoping (although in retrospect I wish I’d measured before and after, I didn’t yet have the measurement mic) but it did improve the imaging significantly.
You are dealing with a number of immutable issues as things stand. The dimensions of your room and the actual output of your speakers. I think you can change your speakers, add mass to your room or add helmholtz resonators. If you are able to add mass with albums, books or other items this will help, although you most likely would need more mass than is practical. Helmholtz resonators are easy to build and the calculations are simple. You could dress these up a bit. You would need to get the dimensions of required resonators and target 2 or more frequencies. 5 years ago I would have steered you away from DSP, but now if you are willing to spend some money it might be a solution. I would imagine you would need to get well north of 1K for an adequate DSP solution but this really doesnt cure the fundamental problems. Too bad you live in an apartment or I could give you more suggestions. 
hudsonhawk OP113 posts02-23-2021 9:38pm@speakermaster Great question and a detail I forgot to mention is that i did decouple the speakers by adding Isoacoustics Gaia feet to the speakers. It didn’t make as big of a difference for the bass as I was hoping (although in retrospect I wish I’d measured before and after, I didn’t yet have the measurement mic) but it did improve the imaging significantly.


In terms of measurable differences, this is unlikely to make any difference. Their may be a slight slight difference, but the vast majority of the energy is coming out as sound, not vibration in the cabinet, especially something as solid as what you are using.

Add a couple of subs and position them so that your nulls hopefully becomes manageable. When you have a +/- 8 db bass freq range you can start to use dirac or similar. Paradigm sells a small and rather cheap ARC unit that works digitally. But if you use Roon comvolution filters they should do very well. Acourate software is fine for Roon. Roon also got PEQ filters for final manual adjustment to your liking. Remember good bass is not loud bass.
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
Reposition L/R mains for best effect ... and you could use the online calculators (for convenience) to identify the room modes.
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.
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.