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Bass resonance problem

A

andrewken

pfm Member
I've recently moved house and have my hifi in a much smaller room. Dimensions are 14' x 12' approx. with a 3m ceiling and wooden carpeted floor. In a significant minority of recordings the bass resonates and is just overpowering. The system I have is probably overkill given the dimensions of my new listening space. I have a Klimax Renew going into a Krell KCT and onto Acoustic Reality Ref 1000 monoblocks (similar to Bel canto ref1000). The speakers I use are Totem Mani II's which I have about 18" from the back wall and about 30" from the side walls. I can't really move them too much further into the room or I'll be using them as headphones!

I really like the Totem's sound so wouldn't want to part with them unless absolutely necessary. However I don't want to spend a huge amount of time demoing different kit if it's the speakers that should go. Anyone had any experience or similar issues and suggest things i might try, including speaker suggestions if that is the controlling factor.

I have very limited opportunity to home demo, I'm based in the south west and most shops I've been to don't stock anything other than Majik or Naim kit up to the 250/282 (netiher of which I would be interested in having gone through the Naim path 10 years ago).
 
You'll have to experiment with loudspeaker positioning. It sounds like you've positioned your Totems coincident with a room node. Move them a foot closer to the side walls and see if that changes anything.

If you're inclined to take a more objective approach, use an SPL meter and measure the room response (to 1/3 octave tones between 20-200Hz) with the Totems positoned in different parts of the room. Chart the results and the best location for them should become clear.

The other possibility is the port-tuning of the Mani-2 coincides with a resonant frequency of your room. You could either dampen that down by stuffing the port with a light wadding to see if that fixes the problem.
 
Thanks for the suggestions. I have very limited space to move them, have tried a couple of different positions, but will experiment further. The stands are on spiked feet through the carptet and have been half filled with attabites, so are pretty heavy and should be damped OK.

Wadding sounds like it might be a solution, but I'm a bit concerned about killing dynamics. I'll try it anyway. Anyone have suggestions as to what wadding might work?

Bass traps aren't an option for me as I've had about as much freedom with the room as I'm going to get!
 
andrewken said:
Wadding sounds like it might be a solution, but I'm a bit concerned about killing dynamics. I'll try it anyway. Anyone have suggestions as to what wadding might work?
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Socks should do to help you rule out the port coincidence. Then you could try leakier solutions like drinking straws or toilet paper tube to lengthen the port (to change its tuning slightly) to take it out of coincidence.
 
Instead of moving your speakers, you could try to move your listening position backward or forward a foot or so.
If you get a big improvement you will at least know if it is likely to be a room resonance or not.
 
Blzebub said:
I have a similar problem. I am getting an acoustician to sort it out with bass traps.
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I got a cushtysan to sort out mine, 900 quid for two things that look like settee cushions seemed steep but the guy's Dad owns a settee cushion making factory:) so they really do defy the laws of physics and were money well spent:)

Only acoustic treatments my local dealers push so they must be good (or expensive enough to make a decent/indecent mark up)
 
To the OP, drop me a pm, I use 7ft Horns in a room about the same size as yours, can't work:-(
Every speaker is a compromise and if you sort the room, you can make the best of most anything!
 
I know it sounds like a hassle, but I WOULD move them way out from the wall, to form a tight equilateral triangle with the listening position (6-8ft). Do this for critical listening, them move them back when you are done. I do that with my maggies, of course they are not that heavy!
 
Obi1 said:
Instead of moving your speakers, you could try to move your listening position backward or forward a foot or so.
If you get a big improvement you will at least know if it is likely to be a room resonance or not.
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It's almost certainly resonance. If I move forwards a couple of feet the boom on the worst tracks ceases. The sound is still quite bass heavy, but probably due to the way those tracks are mixed.
 
Hi Andrew,

I had a similar problem, the room would shake and transmit the sound through the house.

Changed the speaker cable, issue significantly reduced, changed the interconnects and that also took more away after the speaker cables had removed most.

If you want some more details PM me and I can let you know what I did.

Cheers

John
 
Eyebroughty said:
Hi Andrew,

I had a similar problem, the room would shake and transmit the sound through the house.

Changed the speaker cable, issue significantly reduced, changed the interconnects and that also took more away after the speaker cables had removed most.

If you want some more details PM me and I can let you know what I did.

Cheers

John
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Yes this worked for me too. I also changed the feet under my previous huge integrated amp and that curbed and tightened up the bass no end. Using the same feet under the Exposures that followed made no difference whatsoever so it’s a case of ‘suck it and see’.
 
As Bub suggested you will need bass traps to absorb the excess energy at that frequency, if you could measure the room with something like an XTZ analyser that will tell you the exact frequency you need to address , you can use as many bass traps as you like, to absorb low frequencies they may have to fairly substantial ,perhaps two traps with a gap in between.
Keith.
Changing cables will not make the slightest difference.
 
I have Totem 'The One' speakers in a very similar room to yours, and there's easily enough bass, but they are mini in comparison to the Mani2. I can imagine the Mani2 sound a lot bigger and might take a lot of room treatment to correct.
 
I have already tried a couple of different speaker cables and settled on my set of Nordost Frey's. I also tried the Chord Epic super twin. Not much in it, but the Frey's provided a bit more clarity. I've swapped interconnects as well, tried moving between different cables and from RCA to balanced between both DS and pre and the pre and power amps. As suggested above by Purite it made little difference to the underlying problem. I will pm you though to get a more detailed take on how you solved your problem.

Will try a few of the suggestions I've had over the weekend. Thanks for the feedback.
 
My room is the same size as yours I don’t have a major problem but i do feel that resonance with certain frequencies. I was experimenting with this so I stuffed a 2ft square cardboard box with Rockwool compressed fire bats, its surprising that is does have an effect in the room in-between the speakers seems to work well but kills the dynamics a bit
Ill have to look at measuring my room making a proper bass trap
Alan
 
I had this in same sized room. A small number of recordings and mostly CD.

15" Tannoy with ported cabs. Massive granite slabs under stands, then cabs on top. Small bass traps in corners and more furnishings. Better and very good on accoustic music. Still the odd reverberation on a few recordings.

My verdict is that my room interacts with ported speakers. I am using old B&O Sealed boxes in there now. They take everything thrown at them in a very musical and even handed way. The room dictates the final sound of speaker. You could improve the room.........and it may still not be optimal.

The other solution of course is to try some of the other many excellent designs out there.
 
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