DaaD Bass Traps/Diffusors
Well, I'm proud to say that I haven't spent any money on hi-fi for nearly a year (maybe the cost of my new car had something to do with it.... :)) Also, I've been really busy.
Anyway, I decided to walk around and popped into Norman Audio. If you've noticed, they've really expanded and have yet another room on the 4th floor where Stereophile Audio was. I am a firm believer in room treatments (and since my listening room is a dedicated room, I can get away with anything)
Anyway, I was introduced to a line of cylindrical bass traps/diffusers called DaaD by a company called Accustica Applicata. There are a total of 4 models, from the quarter height model 1 to the full height (about 4') models 2,3, and 4. I borrowed 1 each of model 2 and 3. They are about 8" and 11" in diameter (thereabouts as the tubes are not perfectly cylindrical.. more oval shaped). I don't have any information about them basically because I believe in simply conducting listening tests without as few biases as possible (biases such like whether nice colour.... can't help it :)) The design is an attractive white with top and bottom wood ends. You could probably put a table lamp or a flower vase on them if you wanted to. Myself, I don't really care...
Test procedure summarised
DaaD 2 and 3 were tested on the downstairs system that has no room treatment as well as in my listening room which has some room treatment.
One side absorbs the high frequencies and one side diffuses (and reflects). When I say I put it on 'diffuse' means that the diffusion side is pointed at the listener.
After the Joseph Audio 50s were bi-amped, the bass tigthened up considerably whereas previously it was a bit flabby so there are actually no real bass problems to correct in the living room. However, there is weakness in the stereo imaging caused perhaps by the fact that it is L-shaped (and therefore asymmetrical) plus a large 51" TV in the centre.
Placing one trap in each corner, there was frankly not such difference. A reduction in the lower midbass could be heard but as the midbass was not booming I would not consider this an improvement. More tuning as in moving the traps around the room was not really possible given the very fixed location of the furniture.
However, I did put the traps in the centre (right in front of the TV - you know it can't be permanent :)) and there was a very noticeable increase in focus. Given the price of the equipment in the living room, I would that it was a very worthwhile improvement. The improvement from the model 3was significantly greater than the improvement from the model 2. To jump the gun, model 2and 3 sounded about the same in my 12'x13' listening room. I'll describe the increase in focus in detail in the living room section...
For the listening room, I removed the ATTs in my room (the ATTs are tube trap lookalikes made in Malaysia by Calvin Choe) as well as the rear wall sonex panel. The side sonex and the front wall sonex remained and the 2 small triangles of sonex in the rear wall corners.
Trying out the model 3 in the corners, I could hear clearly a reduction in the midbass region. Again, my Proac 1.5s have significantly tighter bass than my Zephyrs. Doing constant A-B-A-B comparisons on the model 3 in the corners. I could not say for certain that the sound was better with the model 3 whichever corner it was in. Basically, in the corners, the traps only deal with standing waves (they diffuse/abosrb a little bit of the midrange which does improve the soundstage slightly - like the ATTs do). Of course, the model 3 is far, far more effective than ATTs in affecting the bass.
There are a lot of things you can do with the model 3. For example, when I placed the model 3 at rear wall centre, the sound of the bass changed very signficantly compared to model 3 at the corners. For myself, I found that it absorbed just a bit too much midbass. However, I suspect that my systems are atypical in terms of the tightness of the midbass (all you tube amp owners [except for Audio Research VT100 Mk II and above...] can confess.... flabby midbass :))
Of course, I have rather diverse taste and I was able to find some recordings that were actually improved considerably by the bass absorbing qualities of the model 3 [well, what to do, hi-fi is like that....] One of the recordings in question is my US-press CD single which I bought from the good and cheap Tower Records Broadway NYC [good prices, fantastic CD single collection] in Dec 00 containing 8 (yes eight!) techno-dance remixes of LeAnn Rimes, Can't Fight the Moonlight. (ok, stop laughing :)) If you listen to techno, you'll find that the model 3 really tightens up the bass and by absorbing some midbass, seems to increase 'contrast' by preventing the decay of the previous note from muddying the attack of the next bass note. This makes the sound more 'dynamic' (because when the new note attacks, it attacks from a quieter level). The effect is pretty cool.... the bass as modified by the model 3 was toe-tappingly good. Makes u want to get up and dance to the beat [this is not a confession by the way :)]
Anyway, who knows? Perhaps the larger model 4, being tuned to a slightly lower frequency, may bring about improvements to my room. In terms of midbass absorption, the model 2 didn't really do much for me (too small?)
Imaging & Focus
Well, I've saved the good news for last. Ideally, you're not supposed to have a rack in the centre and the trap should be against the rear wall but few in Singapore have that much room.
But anyway, I placed the traps (one at a time) in front of the rack and there was a remarkable increase in focus and imaging. Basically, vocals achieved great 'presence' and solidity in the centre without narrowing the soundstage.
The thing is, I try not to overstate differences unlike the usual magazine review. Initially, I could safely say I was blown away by the difference. However, disciplined A-B-A-B-A-B-A-B testing (the sacrifices I make) of selected tracks allowed me to greater appreciate the differences after the initial 'excitement' of the big change is tempered by listening until you're sick of the track [and if after this, you still find it an improvement, then its a worthwhile improvement :)]
My conclusion is that focus and imaging in improved across the board across all sorts of recordings but particularly vocals. As for vocals, normal pop records improved significantly and so did audiophile recordings.
I tested soundstage with the Telarc version of Messiah (the newer John Shaw version) in which the choir is spread left/right with the orchestra in the centre. Soundstage width and depth was very good indicating that focus was not achieved by narrowing the soundstage.
For the record, I listened a lot to:
However, silk purse from sow's ear and all that (i.e. you can't make a bad recording into an audiophile recording)
After a first round of extensive listening, I concluded that the sound was a bit forward which may have been due to the fact that the trap was placed in front of a rack rather than against the rear wall plus the fact that I listen nearfield. Listening on the downstairs system, the sound did not sound forward even though the trap was in front of the TV. This lead me to get up and do some speaker moving around. I moved the speakers slightly further apart (something I perhaps I should have done after replacing my old, deep display cabinets with the shallower Billy Bookcases) and reduced toe-in. The effect was pretty good was the sound becoming less forward and getting wider soundstage due to speaker relocation.
On the upstairs system, I found that at speaker centre, the model 3 and 4 did not have much difference (which is good news for the budget) which indicates that room size has a role to play.
It would be really really messy if I mixed up my comments on the diffusion/absorption abilities together so I'll treat it seperately. Fortunately, the effect of diffusion/aborption was consistent across applications.
Basically, you can 'increase' ambience by setting the traps to diffuse and reduce 'ambience' but lower the noise floor by setting the traps to absorb. I generally preferred the sound of 'absorb'. Actually, I would say that 'absorb' did not darkent the sound in my room but merely preserved the 'status quo' with diffuse 'added' to the ambience. Again, this depends on your room.
For darker recordings like my Julia Fordham CDs, an increase in ambience was very welcome but the status quo (i.e. absorb) was fine too. Still, it was interesting and handy to be able to dial-in ambience (perfect for the obsessive audio enthusiast...)
Compatibility with ATTs
I was not about to throw away my ATTs so I listened to the traps in the centre without the ATTs in the corners and with the ATTs in the corner. Basically with the model 2 in the centre, after putting back the ATTs, the ATTs still peformed their trick of pushing the soundstage slightly deeper into the rear.
I am a believer in room treatments and these traps are very very useful items. I am still pondering whether I should get a model 2 to place between the speakers, but the problem is that I'll have difficulty using my remote control and I have to move it away when I pull down my screen.... sigh.. the dilemma.
However, it is frankly not possible to tell you which model to get for bass treatment wise. You have to figure out the problem frequencies in your room, where standing waves occur etc and tune accordingly. I suppose that where service from the retailer is important.
Focus and imaging wise, the model 2 is a pretty safe bet [with the problem that 3 might bring even better focus if your room is big like my living room].
As for price, call NAW up. They are pricing is such that they are supposed to be cheaper than equivalently performing/sized ASC tube traps.