Big Room, Bad Sound

Was the previous room all concrete walls?Do you know what is behind the plasterboard?,(if anything)The only thing I can think of,is the plasterboard is absorbing the bass.The smaller the room the more absorbtion you should need,but I'm thinking your walls are sucking out the bass,instead of putting back into the room.

Maybe worth getting the freq response of your speakers,where the bass does roll of,then run the CARA freq sweep test they do and see/hear where you bass is cutting of.I used RPG products to help my roo, but I had boomy bass,not bass suckout.But I suspect the plasterboard walls.
 
Here's some calculations based on two dimensional modelling. These do not take into account the vertical axis, which in your case causes an issue.

A double mode or node is the result of two dimensions being either the same or divisable by each other. In your case, you have a room mode at 75 hz across the width as well as between ceiling and floor, with cancellations every four feet or so (well 3ft 9in to be precise)

Can you measure the distance from the floor to the centre of the Proac bass driver? In the meantime, have a go with these two options,

Listening across room (recommended)
Front baffle from rear long wall, either 667mm or 1079mm
Centre of front baffle from side walls,either801mm or1295mm

Listening along room length
Front baffle from end wall, either 801mm or 1295mm
Centre of front baffle from long side walls, either 667mm or 1079mm

There's no guarantee this will work, but it's a good starting point, prior to fine tuning by ear. If the energy suckout remains regardless of speaker position, apply the same thinking to the listening position.
 
Tonester, lots of the other replies have raised the issue of room acoustics - modes, construction issues etc. This is all good advice. But there's a basic point which you made yourself - your new room is much bigger. I had a similar experience when I moved to my current house, 4 years ago, with a much bigger listening room. I tried all sorts of things, but the solution turned out to be simple - I needed speakers with a fundamentally different tonal balance. In my room, speakers in the BBC tradition (by which I mean Harbeths and also the older Spendors - but NOT LS3/5a's) work well. IMHO, most of the competition is balanced in a way that needs the room reinforcement of smaller rooms, and as well as being played at high levels to compensate for the relative insensitivity of the ear to low frequencies.
 
Sounds like a job for Castle Conway 3's then :)

I'll back up what Merlin said about listening across the room. The resonant frequencies across the room are slightly more hifi-friendly than those down the length of the room in this case - just don't sit too close to the rear wall, 3 or 4 feet in ought to do it.
 
Cheers guys, I had a further play with the software last night and I think bottleneck and merlin have hit the nail on the head in that I need to shift the whole room around and set it up accross the room.

Merlin, thanks very much for the specific measurements, it's quite a lot of work to move everything around but I may have a go tonight if not it will be the weekend. Either way I'll report back on the results. I'll confirm the height of the bass driver this evening (with & without the mana).

It's true that I have moved from a small room in a 1930's flat which had solid concrete walls all over 40cm thick. It was only 9ft by 12ft and crammed full of hifi, large double bed, wardrobe, computer deck etc. The new place is just plasterboard or plaster on breeze block.
 
Tone while your at it best get rid of the pulsar points and Mana and have the speakers "au natural" ie spiked to the floor.
See how it sounds then add the fairy dust and see if it gets better or worse.
You should get more bass without the points and mana.
Thats not to say it will be more accurate.
Mana under speakers can help tighten bass but i dont think i would ever want Pulsar points going anywhere near speakers.
Just putting them on your CDP makes it wobble about :D
I have always felt rigid support is the best way to support speakers to let the drivers work to their potential.

Curt
 
I have found the best sound in my room is across the short axis.....





Think the devil has posted on the wrong thread
 
bottleneck said:
zanash, I think he is refering to the Nordost Pulsar Points.
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Or possibly (but probably not) the cabling being used which is Nordost, which won't be helping the bass issue but the room size/modes/layout issues are the critical issues here without any doubt.
 
The Devil said:
I hadn't noticed the cable being Nordost - would ditch that pronto!
Click to expand...

Perhaps I should ditch everything and buy a sony 5.1 setup :p

I did try using some QED Silver annivesary that I had lying around but that closed everything up even more.
 
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merlin said:
How do you ameliorate the affects of a double mode and the resultant suck out with room treatments?
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Just a quick remark before I read the whole thread. Room treatment fills in suckouts as well as taking down peaks - for exactly the same reasons. In practice too: I've watched it happen with repeated frequency sweeps an an incremental damping approach
 
Hi Steve,

in my experience, if you apply enough room treatments to cure the likes of a deep null in the mid bass, you end up with a horribly dead sounding room.
 

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