Unusual HT Orientated Speaker Design

[ShinOBIWAN]

Lo folks, good to be back after a bit of break.

Still cooking up idea's for another project but things have taken a bit of turn. I ended up buying a Yamaha DPX-1100 DLP projector after it came up for a bit of bargain price considering it was selling early last year for £7k. Anyway its pretty much a wet dream as far as home theater is concerned and far better than any of the other projectors I've owned - I think the Yamaha is my 8th one now. I've done the whole music thing with the Perceives and this time around I really want to go for something that will fit in well with HT. Discrete, easy to implement and coherent if you like.

I initially though of in-wall designs but TBH there's no way I can start cutting recesses into the walls. I then thought about wall mount designs that were fairly shallow with all the left, center and right speakers having a matched driver array and non of that horizontal MTM for the center channel. Sounds easy at first but virtually everything cooked up didn't fit right.

After a couple of days messing around I finally hit upon a very simple idea that strangely has never really been done before, yet is almost perfect for the task in hand. Let me elaborate a little; most HT setups are compromised in terms of center channel design and more importantly the placement of this important channel in relation to the left and right's. You'll see most setups with the center channel tweeter axis way down in comparison to the left and right, you'll also see them using horizontal MTM design and mismatched driver arrays. These all serve to rob consistency, realism and generally create a hap-hazard look.
So how do you solve all these problems in one go? You build a single speaker that IS the left, center and right channels. That's really only half the story because the driver choices were equally important and this is thing that I hope will really set this apart from anything else. I've gone for the Manger drivers because quite simply I cannot imagine a more perfect driver for this application, its solves so many problems that its almost criminal to look at anything else for what I'm wanting to achieve.

With the Mangers I'll get a supremely matched array with a driver covering the 200hz-35Khz range for each of the front channels. The acoustic center of each channel will also be in the same horizontal plane and the center isn't compromised through traditional driver layouts. The whole look of the speaker itself is tidy, integrated and most of all unique.

Here's the obligatory drawings:



This one is a top-down shot giving an idea of the profile, you'll not that the left and right driver arrays are naturally toed in towards the listening position.



At the moment I'm not really sure about the driver that will cover the lower range below the Mangers. What I do know is that each will be no larger than 8" and will have around 25ltrs to work in(assuming I use 2 drivers).

I'm planning to wire the bass signals from the center channel over to the two 8" drivers on the left and right arrays.

A bit of concern was the fact that the Manger and bass drivers are in a horizontal arrangement. I'd imagine that crossing at 200hz virtually destroys anything that could be related to such an alignment, I certainly know lobing won't be an issue.

Another concern was that of the effect of mounting a speaker on the wall, clearly bass response will need to be carefully accounted for. I was think that a low Qts bass driver in a sealed enclosure with a fairly early roll-off would be a good idea. The boundary reinforcement from the wall mounting would effectively create a fairly flat response in-room.

TBH the bass drivers will only cover the range ~200hz-60hz. So it maybe debatable as to whether they're actually needed. For example I could just go with a pair of subs that would cover upto the 200hz range. Something like this:



Its a little less elegant than the first solution so I'm not 100%, probably the better route would be Manger with bass driver and then subs covering the lower end.

[soongsc]

I think the concept looks neat! But I think it best to listen to the Mangers and see if it fits your taste. It might also be a bit limited in dynamics if just these are used unless you just plan to watch music videos with this setup.

[boogs]

I think i would opt for your second design. More flexibility with regards to tailoring bass response though admittedly is not quite as elegant in appearance.

Scott

[ShinOBIWAN]

Originally posted by soongsc
I think the concept looks neat! But I think it best to listen to the Mangers and see if it fits your taste. It might also be a bit limited in dynamics if just these are used unless you just plan to watch music videos with this setup.

Should make a nice contrast to what I have now. I'm sure for a modest home theater/music setup it will be OK. I've simplified my goals somewhat since all that Perceive v3 nonsense and I'm really wanting to build the sound system around the stunning picture offered by the Yamaha.

Its a PITA trying to audition those Mangers here in the UK, so I'm resigning myself to buying one and simply trying it out. If its absolutely disgusting then I'll obviously look elsewhere although I'm not expecting the dynamics or presentation that I've become accustom to.

[ShinOBIWAN]

Touched up the design a little more:

[ShinOBIWAN]

Pics of Manger:





Looking forward to playing around with this over the weekend, hopefully initial impressions will be good.

[Bose(o)]

Have you thought about building the center channel into the left and right speakers? You could cross-fire the center channel signal to the opposing listener from each speaker.

[soongsc]

Originally posted by ShinOBIWAN
Pics of Manger:





Looking forward to playing around with this over the weekend, hopefully initial impressions will be good.

Look forward to reading you impressons.

[soongsc]

You might also be interested in reading this before you dign into that center channel.

http://www.222sound.info/english/2pl...ten_in_3d.html

[ShinOBIWAN]

Done a bit more listening and experimenting throughout the evening
and . The Manger is a very good driver.

I've now got an FIR filter on the Manger at 100hz along with a bit of EQ in the 1-3Khz region to flatten it(I think it sounds a little hard without this). I've been comparing it to a single Perceive but the Manger is at something of a disadvantage in bass terms because of the 9" ATC so I've rolled the Perceives off right at the same point as the Manger to match the tonality somewhat.

I've then been flicking back and forth playing each speaker in solo with a mono summed stereo signal of whatever track was playing.

Differences are not subtle at all. I thought I'd really got a spot on sound with the Perceives but what I'm hearing now just doesn't seem quite right in direct AB with the Manger, it seems like there's some kind of noise over the really fine details that the Manger just doesn't have, this is despite uber tweaked crossovers and EQ on the Perceive.

I've got to say I have no idea what folks were talking about when they said the Manger has limited dynamics. I'm comparing it to an ATC mid which is regarded as a superb dynamic performer and it actually sounds every bit as 'live' but with extra's toppings such as a very calm and unforced nature - not boring but just more ordered with greater contrast to the sounds which helps make it possibly sound even more dynamic that the ATC in some situations. Especially good is percussion which I've never heard sound so real, you can get a real 'hairs standing on end' quality with good recordings containing percussion. When played back at realistic SPL's, hi-hats and other very immediate sounds in particular really cut through the room in a way I've never experienced before.

I've only got one driver so I can't assess anything to do with imaging, soundstage etc. But I've heard its the Manger strong point.

On the downside whilst the detail, tonality(after EQ) and general high dynamic contrasts between small and large sounds is good to very good I can't say the same for the clean output when using the Manger within what the manufacturer suggests as an acceptable crossover point. I used a 100hz 24dB/Oct to start off with and found the driver is limited to around 95dB before the sound starts to harden and turns ugly. Afterwards, using a 200hz 24dB/Oct was MUCH better with enough output for my tastes. I did try 300hz too and it wasn't too far off what the Perceives manage. I didn't expect the Mangers to be output monsters but there's absolutely no way they can be used as a full range single driver for my tastes. So its a bit of good and bad there for me, on one hand it will go loud but on the other you need a good steepish crossover at about 200-300hz for three figure SPL's that still retain all the Manger qualities.

Its all very early days yet and this is just a quick initial impression after several hours of fooling around. I've got some serious reservations about handling the rear wave - the driver seems uber sensitive to this and makes or breaks the sound IMO, I'll have to do some experimenting here for sure.

BTW Forgot to mention that I was using the Manger OB on a scrap of MDF roughly 0.4 x 1m with the driver about 15cm from the top and offset slightly. Next up is a sealed box with six 2" layers of acoustic foam effectively creating a 30cm thick barrier within the enclosure, not sure how it will sound but it will pretty tell what happens when you virtually eliminate the rear wave through absorption; my prediction is a loss of life, drive and dynamics to the sound.