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?
So an update here: nearfield measurement shows the speakers, unsurprisingly, have an almost flat response.
And massive kudos to those who said the 120hz spike was a harmonic - you win a prize for that one. When generating a 60hz tone, the spike at 120hz is visible on the analyzer. Very interesting!
For now, I’ve been able to do a little EQ’ing to address the problem, at least with music played from my music server. Interestingly I didn’t really like the results when using a convolution curve in Roon - it reduced the bass way too much - and I ended up just using Roon’s parametric EQ, using the room’s graph for reference.
Longer term, I’m arranging a demo of the PSI AVAA C20, and waiting to see what happens with our lease before deciding between that and more bass traps.
This is a classic example of a system that can benefit from a properly integrated sub. In almost every room there will be a place where the speakers image best and have the most even natural response above 150Hz. There will also be a place where the speaker’s bass response will be the most even. I have yet to work in a room where those two places are the same. You likely don’t have the floor space to optimally place a sub, so there will be concessions.
In my experience, proper listener and speaker placement is always preferable to any amount/type of EQ, but your hands are tied. You’ll have to work with EQ to tame this, but try to use the absolute minimum that gets you an acceptable balance between engaging sound and a resonant mess.
And anything that you do to try to fill in dips in the response using EQ will be a disaster! What you’re seeing in that response curve is cancellations and emphases. If you can knock the peaks down, even by 1-2dB with better placement of speakers and listener (stay away from that back wall as much as possible), it should also bring many of the troughs up. You’ll be chasing a series of tiny victories that will add up to the best your system will get in that room.
I suggest that you try using a more acoustically transparent plug for the speaker ports, as the ones that come with most speakers are so dense that they create enough back pressure to stifle the natural sound of the driver(s) that share the port cavity. This won't help the excess bass but it will likely improve the overall sound.
I agree that the best way forward on the 120Hz issue is to do a nearfield measurement of each speaker separately to see if the issue is with your speakers, mic, or a room resonance. Common room resonances are often caused by light lamps, wall sconces and recessed light fixtures. If you have a signal generator, input a 120hz (+/- 5Hz) steady-state sine wave into the system and you’ll likely find the problem pretty quickly.
Like many of us, I have also struggled with bass - too much, too little, uneven room response, etc. I recently purchased some Townshend Seismic Podium isolation devices. These are essentially steel platforms with spring loaded adjustable cylinders at each of the four corners of the platform. As much as I had followed somewhat conventional thinking and had spikes on my speakers I decided to give these things a try. I must say they positively transformed the performance of my speakers (Linn Akurate floor standers). The bass problems have been dramatically resolved. They are not cheap but they really do tame the bass and I could not recommend them more emphatically. Try an outboard bass equalizer along with these "podiums" which were reviewed in the Jan., 2021 issue of Absolute Sound. This article also contains contact information for the US distributor who is located in S. California and was very decent to deal with.
try a jl112/3 or a velodyne dd12/15. locate it on the same wall as your listening position but a ft or 2 out into the room. reverse the polarity on the sub then tunre w/phase control on sub. You will be amazed at how the room will flatten wrt bass response. I have eq curves I can share w/you showing how the room modes become less dominate. This a a solution, the other solution is to get smaller speakers like Harbeth M30.1 or .2s w/a sub.
I wonder if you're getting to much bass reinforcement from close placement to the wall behind them. If possible (as an experiment), pull them out so you have 24 to 30 inches of space behind the cabinet and see if that evens out the response. If that helps, and living accommodations require close placement to the wall, it may be possible to place a bass trap directly behind the port at the bottom of the speaker and allow your current positioning.
The other possibility is - Eggleston has great bass to begin with and the Kiva's may be too large for your space...
OP, ignore the comment from @mijostyn that 'bass traps don't work' This is blatantly wrong. Bass traps most definitely work but the 5" thick panels GIK supplied are not proper bass traps, they form broad-band absorbers and are very useful. They are in business to sell so be aware of being sold too many absorbers which will dull the room down.
I see about 10dB between nulls and peaks which really is not too bad.
Looking at the CSD you provided I don't see the 120Hz peak being any higher than the other peaks. The suggestions to use EQ to boost the partial nulls will bring no you no happiness. Using EQ to pull down the peaks will work BUT only for one listening position which is rather restrictive.
As I am sure you know, to gain 3dB, it takes a doubling of power. I don't know how loud you listen but to gain 9dB of boost you would need to double the power into the speakers 3 times, so if the 88dB speakers are using about 60 watts average on peaks, then to bring the nulls up to that level would require 480W. If the amp can't provide 480W clean power then it will clip and when it clips the wave begins to take on a square shape and a square wave is just a sine wave with harmonics. Danger! Harmonics are higher multiples of the fundamental so the crossover does it's job and sends high frequencies to the tweeter which is not designed to handle that kind of power and it politely fries itself.
If the missus won't allow full sized super-chunk bass traps, take heart, you can employ a Distributed Bass Array. Read up on Geddes and Toole on multiple subs and how to deploy them. This will smooth out the modal region below the Schroeder frequency and you will no longer be confined to just one spot. With a smooth power response the whole room sounds good. The 3 or 4 subs recommended randomise the nodes and you get many more but smaller partial nulls and peaks. Needs to be heard.
A DBA is great but although you now have smooth bass it still needs to decay within the correct time for your size room and this of course will need bass absorption. Gearslutz was mentioned and has an acoustics forum with much good info.
Hummmm, Maybe that's why I've never see one on my stuff. 2496 Behringer, it's their mic, it's all their stuff. Your saying the equipment the mic is hooked to may have a ground loop? AND that through rectifying it, that causes that spike.
It doesn't sound so "Rectified" "To be made right" A2D Can you hear a spike like that A2D, or Erik?
OK I'll DMDD, I'll learn.. Maybe:-)
OP, can you hear that narrow spike?
Maybe I need to see if I can make it happen, and give it a listen..
I guess I'm lucky. I have been in the same home for 40 years, May..
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.
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 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!!!
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.
hudsonhawkOP113 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.
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.
@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.
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.
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
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 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.
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
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.
@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.
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 “....
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...
@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.
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.
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.
@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.
@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).
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.
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.
@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.
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.
@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...
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..
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.
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.
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...
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