Room boom problem

A square room will always be difficult, although you may be able to mitigate the problems to some extent by adding and moving furnishings around. "Sparse" room styling probably isn't helping here!

I used to have similar problems with a SU in a similar sized room. I was surprised to find that when I upgraded to NDX/282/200, the problem was very greatly reduced, far more than any changes to the room and furnishings.

In your situation, I would consider using REW or similar software to look at the room acoustics, and consider adding some bass traps. 

Try demo’ing a set of Stillpoints Ultra SS under the speakers. Prepare to be amazed! I’ll lay money the boom will disappear and you’ll hear the bass as never before. Not cheap, but definitely  not snake oil.

A square room means the same bass standing waves in two directions, effectively doubling the problem. Ither than best speaker an dlistening postion placement  to minimise, there are three options: 1) if you are not interested in low bass, changing to speakers  that do not go low enough to excite the main resonances 38Hz, also 51Hz, 76 Hz... 2) introduce bass absorbers in the room, thoughto be effective these may need to be large, and multiple. 3) use DSP to reduce powe at the peak wavelengths, though if extreme this could cause other distortions, and I don’t know how effective.  Best bet if 1) unacceptable is as much 2) as you can plus 3) to get as good as you can. 

It doesn’t take much to break the squareness, an alcove or a bay window will do it, is the room dead square or does it have a feature or two?

I have a second system in a 11’ square room except there is a 1 metre section of wall that drops back half a metre where the door is. I have allaes on the longest wall that has the door at one end, they gave one note bass in one position and it evened out half a cm further out. I started out positioning using the sumiko master set method but the result for the first speaker was indeterminant, it’s rather better suited to free space speakers but I got a hint of where to start with the allaes, if fact it wasn’t far off once I’d settled on positions.

I have Proac D40R's and they are ported out the bottom.   The Herbie's Audio Lab Giant Fat Glider footers solved the boom at my house.  $100 per speaker and I was home free.   I have hardwood floors and plaster walls, so YMMV.  They also took the feedback out of my turntable using complementary Herbie's products.

Smaller rooms will always impart some colouration to the sound particularly the bass or mid-bass region. Perhaps I was lucky as I always managed to ameliorate ill-defined bass or mid-bass by speaker positioning and toe-in (biggest impact here). I also place some diffusive elements beside the speakers (potted plants) and several large canvas paintings on the side walls which helped a little, not too much in the bass but it creates better clarity. 

As others have suggested, footers for speakers (or equipment rack) may help to a certain extent. You would not know unless you have tried. Placing your amps and power supplies on different racks may produce a slightly different bass quality - I've tried so I know. Aftermarket room treatments such as bass traps are large and unsightly so they usually don't do it for me but you can consider them if it's not an issue to you. 

in the end, it depends on what route you intend to take. Of course, the easiest is to consider smaller bookshelves but be warned, they usually don't satisfy as much when compared to a partially optimised large speaker setup, say 80 to 90% on the scale. It's mainly in the bass and scale the larger speaker does so much better. No doubt the small bookshelf can sound very good with little to zero bass problems but when compared to a reasonably well setup larger speakers which do not exhibit serious bass issues, the large speaker will always sound more satisfying to me. 

My advice here is try and avoid ported speakers ..... socks in ports kill the dynamics and slow the speaker timing. In my experience the boom and resonance seem to couple with the driver via the port and you get a kind of feedback.....

Richieroo posted:

My advice here is try and avoid ported speakers ..... socks in ports kill the dynamics and slow the speaker timing. In my experience the boom and resonance seem to couple with the driver via the port and you get a kind of feedback.....

I concur, in that to me good infinite baffle/controlled leakage or isobaric enclosures have always been my preference for controlled bass. The speaker design will not remove a room resonance, but a tuneful, articulate and controlled bass will mitigate the muddle. Obviously speakers with a lower bass roll off, ie small bass driver/enclosure size don't excite low bass resonances as strongly as full response designs, so if you can accept that the bass doesn't go low that's the option I would take.

As Ryde qualified with his post, "larger speakers which do not exhibit serious bass issues" are more satisfying but the point where you get there to me is pretty high on the scale. And to my ears, it isn't until you spend huge amounts of money, (here in Australia around $10k AUD), that a speaker is going to be well enough made that the enclosure doesn't resonate or transmit secondary lower bass, and it's even worth thinking of reproducing the lowest register. At lower budgets a less ambitious bass extension with a smaller, better built cabinet and quality drivers achieves a better compromise (to my ears).

Solutions based around bass traps, dampening are all good, but avoid the problem in the first place is better.

One alternative - is to use a small quality sealed speaker ......... and then use multiple subs - and the subs would need room correction - this would probably solve the room issue....but it ain't cheap.

If you really want to test your room out for boom ..... try Lapa 'Spirit Vessel' album ......... there are several tracks on there that are real trixy ...... if your room is going to boom this will provoke it..........!!! enjoy....

You could try a source that can remove the problem frequencies (other manufacturers and software on PC are examples).

Or go with a good quality standmount / sub combination - with a sub with lots of adjustment features (e.g. PMC Twenty5, but there are many others), which will allow you to separate the bass issue from the rest of the system and deal with it appropriately.

Richieroo posted:

One alternative - is to use a small quality sealed speaker ......... and then use multiple subs - and the subs would need room correction - this would probably solve the room issue....but it ain't cheap.

This is the correct engineering approach, but it's not as expensive as you may believe...

Sealed cabinet subwoofer: £500 - £1000

Cables £50

plus

miniDSP 2x4 £90 + miniDSP UMIK-1 £85 + Room Equalisation Wizard (software) - free.
OR
Antimode 8033-S £305

Cables £50

When correctly positioned (to allow for the group delay of the sub's amp), you only need 1 sub.

I forgot to mention, when posting above re Stillpoints, that my listening room (aka the lounge!) is a perfect square (16’ x 16’) and the floor is of the wooden suspended variety with no carpet! I tried the Herbie’s Gliders as mentioned by Skip, but with only limited success. The Stillpoints absolutely nail the boom. I’m sitting here listening to Lapa’s ‘Spirit Vessel’ as suggested by RichieRoo - pure bass, no boom, no problem!

Same with finite elemente cerabases and bass traps in the corners.

Timmo1341 posted:

I forgot to mention, when posting above re Stillpoints, that my listening room (aka the lounge!) is a perfect square (16’ x 16’) and the floor is of the wooden suspended variety with no carpet! I tried the Herbie’s Gliders as mentioned by Skip, but with only limited success. The Stillpoints absolutely nail the boom. I’m sitting here listening to Lapa’s ‘Spirit Vessel’ as suggested by RichieRoo - pure bass, no boom, no problem!

What such things do is  isolate from the floor, and thus stop the foor becoming a large uncomtrolled resonant radiator,

(Out of interest, what speakers are you using)

However, isolators can do nothing for control of standing waves, and in a square room those can make for very significant peaks and troughs in response - some points in the room with complete absence of some bass notes, while others points overwhelmingly strong bass at those same frequencies, hence how crucial positioning of everything can be to minimise the effect. That in itself isn’t boom, but would become boom if the reflections continued for a significant period of time opafter the speaker cone stoppes moving, which is where room treatment can help.

Innocent Bystander posted:

Timmo1341 posted:

I forgot to mention, when posting above re Stillpoints, that my listening room (aka the lounge!) is a perfect square (16’ x 16’) and the floor is of the wooden suspended variety with no carpet! I tried the Herbie’s Gliders as mentioned by Skip, but with only limited success. The Stillpoints absolutely nail the boom. I’m sitting here listening to Lapa’s ‘Spirit Vessel’ as suggested by RichieRoo - pure bass, no boom, no problem!

What such things do is  isolate from the floor, and thus stop the foor becoming a large uncomtrolled resonant radiator,

(Out of interest, what speakers are you using)

However, isolators can do nothing for control of standing waves, and in a square room those can make for very significant peaks and troughs in response - some points in the room with complete absence of some bass notes, while others points overwhelmingly strong bass at those same frequencies, hence how crucial positioning of everything can be to minimise the effect. That in itself isn’t boom, but would become boom if the reflections continued for a significant period of time opafter the speaker cone stoppes moving, which is where room treatment can help.

Speakers are ProAc K6 (272, 555PS, 250DR) with Chord Epic Reference speaker cable and Super Lumina interconnect. Speakers are positioned approx. 2’ from back and side walls, with minimal amount of ‘toe in’ (approx. 5°). I don’t know anything about the physics of it all, just that after trying 4 or 5 isolators at various price points I gave in, tried SP’s and effect was magical!!

For me, as for Timmo, the finite elemente cerabases, similar product to Stillpoints, gave better controlled bass, cleaner , and also more natural sound with better separation of instruments.

My cerabases replaced the spikes of the speakers.

Thanks everyone for all the advice, I've been away from my computer and HiFi a bit the last while so apologies for not getting back sooner.  I've certainly learned a lot from all of you!

I don't at this stage want to go down the route of bass traps or other room treatment, and don't have the resources to upgrade the SU itself any further.  I did try some isolation pads (kindly lent by the dealer) under the speakers, which together with bunging the ports did deaden things a bit.  Still I got a headache when I turned the volume up, and something really sounded not right!

I had a chat with my dealer who suggested trying something sealed: Harbeth P3ESRs or Spendor A1's.  And possibly also giving the Quadral's standmount equivalent (the Style 2) a go.

This thread should be retitled “Room Boom Doom and Gloom”.

Not helping solve the issue, I know, but just my sense of humour. 

If there's one thing I learned from this is: home demo!  I've effectively had one thanks to my nice dealer, but we'll have a proper in house demo before I settle on the next pair.

I agree with all the above with the following proviso:   Herbie's Fat Gliders have worked very well for me, are precisely what I needed,  and are a bargain at the price.   As to sealed box speakers, I have admired the Magico more than the Harbeth, but the ProAc has a feature many of you can relate to:  They look great, my wife likes them, they are paid for, and with the Herbie's tweak and the ribbon tweeter, they sound very good.  To me, audio is more about the highs than the rest, and the ProAc's do a distinctive job in that department.  We live several hundred miles from every Naim dealer I have ever done business with, so buying speakers is a crap shoot for us and we are slow to change.

As to the Herbie's products, I have used them to set up the ProAc's and the Verdier, too.  I can put the cartridge on the LP, turn the 552-Superline-500 up to 12:00 or higher, tap the stand, and I get zero feedback.   That and the price made a believer out of me.