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bass boom

Neil P

Neil P

pfm Member
I'll soon be packing up the system ready for refurb, so won't be going down the REW / mic / room treatment route any time soon. However, are there any likely ways to reduce bass boom in a room? Floor coverings? Book shelves in corners? hanging pictures on bare walls? It's a family room so can't be covered in GIK panels.

The floor is wooden ... possibly suspended, will lift up a floor board in the coming weeks.

Diagrams and detail to follow.
 
Neil P said:
Only no 3 is possible.
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In that case the only option you're left with IME is using EQ to cut the frequency that's causing the boom, because if the boom is unacceptably loud and you are not allowed to ameliorate it by moving speaker and/or listening position, then you'd need to spend a fortune on - and give up a huge amount of space to - room treatment that, when installed, will have a similar effect to moving your listening seat a couple of feet further away from the wall. It would be helpful to know what frequencies are booming, as the higher the frequency, the easier it is to treat.
 
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It could be the interaction between amp and speaker. Not likely to be in the source of any kind. Have you tried different amp-speaker combinations?
 
les24preludes said:
It could be the interaction between amp and speaker. Not likely to be in the source of any kind. Have you tried different amp-speaker combinations?
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No, its the room. Standing waves will cause the resonance. The frequency will depend on the room length. You can test this out by walking slowly from one end to the other whilst playing back certain frequencies (loads on youtube), you will hear the change depending on your position.
 
I've been looking into this for my room and the options seem to be (bearing in mind I know the root sum of not a lot of about all this)...

1. Bass traps and the like will eat a lot of physical space, to absorb bass requires mass. Panels won't do it for bass. Though bookshelves filled with books, furniture and other bulky big things can help as they add enough physical mass to the room.

2. DSP correction, seems an obvious route, something like MiniDSP but have it only affecting the bass frequencies. I had some similar software with the active Buchardts I had that worked below 500hz and cleaned up the bass nicely.

3. I'd imagine you've already tried, but have you tried bunging the ports up? I needed to with my Dynaudios because of too much boundary gain. Worked perfectly to remove some bass overhang I was having.
 
lAmBoY said:
No, its the room. Standing waves will cause the resonance. The frequency will depend on the room length. You can test this out by walking slowly from one end to the other whilst playing back certain frequencies (loads on youtube), you will hear the change depending on your position.
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Does this relate to what I'm experiencing that if I sit on the edge of my listening seat about 1ft away from usual sitting position the bass significantly drops in perception?
 
Columbo said:
Does this relate to what I'm experiencing that if I sit on the edge of my listening seat about 1ft away from usual sitting position the bass significantly drops in perception?
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Yes, you're moving your head closer to the null in the centre of the room where the groups of standing waves meet and cancel each other out.

DSP is one option but it's not the best as it can't fix anything in the time domain, i.e. ringing. The best option, if room treatments and bass trips aren't possible, is to move the speakers or consider partially (or fully) bunging the ports if they're not sealed.
 
lAmBoY said:
Try tilting your speakers up a tad, This will affect how they interact with the room. If you can keep the tweeters firing at your listening position.
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I can't see that doing anything other than ruining the stereo image, since bass is very non-directional
 
Hcanning said:
I can't see that doing anything other than ruining the stereo image, since bass is very non-directional
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The imaging effect comes from the higher frequencies being more directional, hence the suggestion to keep the speakers directed to the listening position, but angling them slightly. This changes the direct reflection from the rear wall. Worth a try, stick some coasters/coins/etc under the front spikes. IIRC ATC recommends this.
 
Nigel said:
The loudspeaker woofers will be too big for the room.
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I was wondering the same.

I've only ever managed to get rid of boom by changing speakers and then adjusting position. And that might, n the end, be cheaper than adjustments.

I've dem'd great systems in a listening room that then didn't work in my smallish room. Your system sounds fabulous but is it worth trying floor standers? I tried some A6s a few years ago and then ended up with floor standers with a leaner bass. Depend how much of a bass beast you are I suppose.
 
lAmBoY said:
The imaging effect comes from the higher frequencies being more directional, hence the suggestion to keep the speakers directed to the listening position, but angling them slightly. This changes the direct reflection from the rear wall. Worth a try, stick some coasters/coins/etc under the front spikes. IIRC ATC recommends this.
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I'd love to see some technical citation for this, as bass is not directional - to change how the low frequency waves move around the room, the speaker needs to be shifted horizontally or vertically, not tilted.
 
Has anyone found that dense wooden floor on foil/foam underlay can affect sound? I mean everything affects sound, but I wonder if the entire floor (floating on its underlay) can some how wobble in time to deep bass?
 
I once put my JR149 Mk1s about 30cm from the floor (wood, not floating) and the result was boomy bass. I posted about it here, I can't find the discussion, but someone said (quite rightly) that the problem was the height - the floor was doing something to the low frequencies and that made the experience boomy. Defo worth raising them to see if that reduces boom, I mean it's easy to do! I'll search more thoroughly for the discussion later, as it's annoying me that I can't find it.
 
mandryka said:
I once put my JR149 Mk1s about 30cm from the floor (wood, not floating) and the result was boomy bass. I posted about it here, I can't find the discussion, but someone said (quite rightly) that the problem was the height - the floor was doing something to the low frequencies and that made the experience boomy. Defo worth raising them to see if that reduces boom, I mean it's easy to do! I'll search more thoroughly for the discussion later, as it's annoying me that I can't find it.
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They are floor standers, but I can rest them on a chair each, to see what happens. The walls, I should add, are bare plaster at the mo, the only furniture is 2 sofas, and a flimsy bookshelf covering an archway into another room. It is possible the bookshelf back is wobbling along with the bass.
 
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