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New Room Layout causing Bass Issues

jimbob75

jimbob75

pfm Member
I've moved our lounge around and re-positioned the speakers so that they are now firing lengthways (see indicative sketch). Old layout had the speakers either side of french doors with sofa alongside opposite wall.

ROOM1.jpg


The sound overall is now excellent...BUT....I am having issues with the bass. From the listening position (across full length of sofa) the bass is very tight but very lean. On some tracks it is barely discernible. However, as you stand up the bass becomes much fuller. This fullness turns to 'boom' if you approach the speakers whilst standing.

The speakers are approx 30cm from back wall, and I have tried pulling them further out / closer / further apart / toed in etc etc but nothing seems to cure the bass issues.

I have read that my speakers (Quad 22L2) can be a pain to position and can sometimes overwhelm in the bass region. However, in the previous layout the bass was excellent, even relatively close to the wall. I did briefly have one speaker in the corner and the results were excessive 'boom'.

So, can anyone suggest what in the room may be causing this? The footstool/sofa? Reflections from the rear glass doors? The top right corner? Ideally the solution will not involve having to invest in room treatment/correction, of which I have no knowledge, nor inclination.

Would different speakers react better to the room acoustics?

Is the problem the speakers, the room, or the relationship between the two? Would new speakers possibly sound better but still be battling against the inherent issues of the room?

It's incredibly frustrating because if I could just boost the bass from the listening position then the sound would be perfect!
 
You may have to move the speakers or the listening position, I imagine you are sitting in a bass null at the moment, where the bass is cancelling itself,
Keith .
 
The TV is above the fireplace so the speakers need to remain roughly where they are.

Any ideas on what could be causing the 'null'? If nulls are caused by bass reflections bouncing into each other is the solution to absorb / re-direct one of these reflections?

I had hoped that the bookcase / sofa / curtains would go some way to achieve this.
 
Can you supply some dimensions/measurements? IE. what is the distance from rear wall to sofa and what is the exact distance from wall to speaker baffle?
 
Rear of sofa to rear wall 85cm. Wall to baffle 60cm. I have no equipment to measure frequency response, if that is what you're referring to.
 
In your old position with the sofa against the rear wall you were avoiding pretty much all lengthwise modal nulls (sound pressure is highest near a boundary, while velocity is lowest; the ear reacts to pressure). You were only plagued by the nulls of the vertical and sideways modes. And the latter of these probably with not much ill effect as I presume a lot of sound gets through the glass doors, making the room appear larger in that direction?

With the new position you no longer are in the pressure zones for any main modes (i.e. a loss relative to what was before), and you are in a main sideways null which has moved up to 48Hz and probably became more audible, again a loss.

I suggest you enter your room dimensions into

http://www.hunecke.de/en/calculators/room-eigenmodes.html

And have a look at the individual nx and ny modes, while imagining the position
of that sofa.
 
Purite Audio said:
You may have to move the speakers or the listening position, I imagine you are sitting in a bass null at the moment, where the bass is cancelling itself,
Keith .
Click to expand...

+1 on that.
The predominant mode with your speaker & seating positions is length
Depending on room mode Hz some places between seating & speakers will have either overblown or reduced bass. Same for height, standing up is one either overblown or reduced & sitting might be the opposite, same mid room vs corner.
If you give some room measurements (metres please) it will be useful for us to help u out
 
I am using Quad 22L2's too in an identical size room to yours. I have mine configured in your original position firing across the shorter dimension. There is a solid wall behind them and I have french doors and curtains where your glass ones are. Sofa is where you had yours. The Quads are a bugger to set up right, it took a lot of experimentation. I ended up with them 40cm off the back wall and toed in slightly (baffle 66cms from back wall). If I sit back in the sofa, the sound is good, but if I lean forward about 30cms everything tightens up and the soundstage is enormous. When you get the Quads set up, they positively sing. I suspect they don't like firing into the longer dimension.
 
ROOM1.jpg


I agree with Keith. I'm a thirds man; you know, photo layouts, woodworking, that sort of thing. I'd have a chair moved forward so the listening position would have my head a third of the way up the room. Though completely impractical in this instance, the Glass Doors would be an ideal place for bass traps. I also have a habit of locating speakers in the corners of the room first, allocating at least a square metre for positioning, and then making Bookcases and Equipment Racks fit around them. To me your speakers are too close together, and you're sitting too far away from them. Where possible, I've always tried to avoid having my listening position near a rear wall.

In my opinion, you don't need new speakers, you need to purchase a new chair. Would this work? Locate your Bookcase on the French Doors wall, facing you as you enter the room. Sofa where Footstool is now. Footstool gone. Loudspeakers wider apart into corners. Equipment Rack at end of Sofa, round about between where the Bookcase and Footstool are now, which also provides a comfy seat for headphone listening. New moveable solo listening seat positioned where the Sofa indicator arrow is now.
 
Thanks for the replies.

I had presumed firing lengthways would be a good idea - it has taken me years (and a new TV) to convince the dear wife that this would be the case! Now I seem to have opened a can of acoustical worms....

Room layout as suggested by John not practical. I have stuck a big vulgar TV on the wall above the fireplace and the position of sofa / speakers is ideal for films / family viewing etc. This was basically main motivation for current room layout.

How much interaction do the furniture / furnishings have over the sterile room measurements?

<More accurate dims are: 3.55m width, 4.8m length, 2.35m height. Speakers are 152cm apart from edge of cabinets, 2.5m from edge of sofa>
 
I have a very similar room layout to the OP. My room is around 0.6m wider and 1m longer, but I have the same firing arrangement, and double glass doors behind the listening position and the internal door in the same location too.

I had problems with bass boom, and I also have the "bass increases if I stand up" phenomenon. The bass boom was largely cured by speaker positioning. I tried the speakers one fifth of the length of the room from the rear wall, and each about one fifth of the width from the side walls and there was significant improvement straight away. This is much further into the room than I would normally have tried.

The final improvement came when I moved one of the speakers a couple of inches sideways - I couldn't believe how much this affected the boominess, which is now all but gone apart from a very few tracks, and even with these it doesn't overwhelm as it did before. I doubted my ears/memory so I tried reversing the move and the boom returned.

So I suggest pulling speakers around .9m away from your rear wall and experimenting with lateral placement - even a couple of inches can make a difference (as the bishop said to the actress).
 
Why not just go back to where it sounded great, I've often tried new layouts and had to eventually , after much fettling and fiddling , admit they didn't work..
 
jimbob75 said:
<More accurate dims are: 3.55m width, 4.8m length, 2.35m height. Speakers are 152cm apart from edge of cabinets, 2.5m from edge of sofa>
Click to expand...

I think you have 2 problems - lengthways you are sitting in the null and widthways you may have cancellation between speakers. If the 2 frequencies are related and the width issue is compounded by an unfortunate ratio of speaker to side wall and speaker to speaker distance then you have a double whammy.

Step 1:
Listening to only one speaker move it backwards and forwards until you get a less obvious null 2/3 of the way down the room.
2:
Adjust the other speaker to the same distance to the back wall and, listening in stereo, try moving each speaker sideways. This hopefully will tune out the main harmonics that interact with the lengthways mode.

The problem I can foresee is that if a better sounding position is found it will look shite because it will be asymmetrical around the fireplace.:(
 
Jim,

I too had some acoustic issues when i changed my lounge recently and it seems to me that if your settled that this is the layout that the lounge is going to stay then you have 2/3 options.......

1, change the speakers
2, speaker positioning
3, sound panels

I would presume that option 1 is drastic BUT believe me thats exactly what i did in the end after much speaker placement.
You could try sound panels in each corner behind them to deflect or dampen bass notes even try to site speakers on chopping boards or paving slabs you could try to have the speakers firing slightly upwards by lowering the spikes at the back so the speakers lean back a tad to lift the sound higher which may help.

Theres endless possibilities that may ultimatly drive you nuts but hey this hi-fi malarky is great when it all comes together......dont give up try everything first that people are suggesting before making a drastic change.

Good luck my friend - i know where you are coming from.

Scotty
 
Thanks again for the continued replies.

We'll assume current layout re: speakers / sofa is fairly fixed.

I'll have another go at slight changes to the speaker placement - I can't move them out too far because I have two exuberant young boys to contend with. They are currently angled upwards very slightly (floorstanders btw) but I'll push the angle further to see any change.

I am not averse to switching speakers, although would probably be looking second hand, so lack of a potential home demo (which would probably be critical) is an issue.

Those frequency calculators are probably great, but I'm just a simple bloke who wants to listen to his music - does hi-fi have to be so bloody complicated...?!
 
It's not complicated, just put your room dimension in, along with speaker and listener positions and see the frequency response. You can move the speakers and listener about and see the changes in the response.
 
Your sofa is now in the ideal place acoustically given your restrictions. You are probably just used to having the room gain boost your bass if it was up against a wall before.

Either move the sofa forward or back a bit or buy some speakers with a lower bass roll off.
 
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