MTMWW thoughts . . .

[Pete Schumacher ®]

Wayne Wendel will be coming by tonight to audition the MTMWW and critique my poor woodworking skills. I can't wait.

OK, some more thoughts on the MTMWW listening impressions.

I removed some of the fill in the lower chambers. I had R13 fiberglass batts mashed a bit by acoustic foam on all walls except the front baffle. Now, only the back and one side wall have the R13 with one wall covered only by acoustic foam. It's hard to guage by ear, but I do think that helped the low end a bit. I may take some of the stuffing out of the upper chambers as well.

Strong points:

Bass . . . What great bass! It's been a while since I've heard bass this nice. When first looking at those little woofers, you're thinking there's just no friggin way that sound comes out of those little towers. I've got a 2.6 cubic foot box with a 24Hz tune using a 10" long 3" ID PVC tube. Some may think it's tuned a bit low, but after listening to some pretty dynamic program material, I'm concluding that the low tune has merits.

On Ayreon's "Into the Electric Castle", the opening track has some really deep bass notes and the second track finishes with some really low stuff too. On my Peerless HDS - Morel TM, the 7" cones, in their ported enclosure tuned to 48Hz, just flopped wildly and distorted badly. The fundamentals are just too low and strong. However, the Quad DA175 in that low tuned box handled those notes without strain. If the box were tuned higher, I doubt that they could have handled that bass crescendo.

Stand up bass on jazz cuts is also excellent. The large mallet slams on the huge bass drum on "Night on Bald Mountain" from Stokowski sound were easily distinguished preceeding the deep bwoooooom. And electric bass of the type flased by Tool is presented with authority.

Mids . . . Complementing the bass quite well are the lower mids. I think the BSC is set about right with the current XO since the transition from the lower bass notes to the upper frets all sounds like the same instrument. Saxes and horns sound great on those lower notes too, real full bodied.

Highs . . . Nicely detailed and extended.

Weaknesses:

On louder passages I do believe the compromised XO point for these drivers reveals the shortcomings of the drivers. We're at the point where 3rd harmonic is going up on the DA175 and distortion is increasing in the K1. During loud rock passages, which can really be quite a bit "louder" than symphonic recordings, there is noticeable listening fatigue on some tracks. I think the "hot" recordings, with their accentuated mids, tends to focus a lot more energy in the crossover region and therefore highlight the weaker performance areas of the drivers. But if the volume is backed off a bit, they're much more listenable. This phenomenon was really noticeable on rock passages, but almost imperceptible on the jazz and symphonic stuff. But hey, what do you expect from a $9.00 tweeter?

Improvements:

The concept works! As a really cheap tower system, it's quite listenable as long as you don't push the tweeter too hard. These woofers are just fantastic when matched up in the quad array. That said, I've worked up a new XO to accomodate the Peerless HDS or SEAS 27TBFC at a 1500Hz. That, I would think, will open up the sound by allowing the DA175 to roll off as its 3rd harmonic is increasing. It's no longer quite the "budget" system, but still not ridiculous in cost. I love the woofer array idea so much that the next box will have three sets of series wired pairs, 6 woofers in all, mated to the RS52 and ND20-6.

That sextuplet array will probably be my last DA175 design for a while. On to tackle Nomex cones . . .

[paul_n_oneal]

Nice writeup Pete and be sure to Post Wayne's results ASAP. I'll be checking the board periodically tonight. I'm going by to take some pictures of the room layout for the prism speakers I'm making for her. Unless I change my mind again, which I do frequently, I will be using the RS150 8ohm now and some Morel MDT-20s that I have here at the house I will sell at a discount to her crossed at 2000hz 4th order. This is going to be a very interesting project and some great learning on how speakers react with 1/2pi space. Plus, if I can make this work and sound good, I bet a ton of people would just love to make some of these for placing out of the way in a top corner .

Paul

[curt_c]

> Wayne Wendel will be coming by tonight to
> audition the MTMWW and critique my poor
> woodworking skills. I can't wait.

Wayne is a great guy. He's always been able to pick out the weak spots in my designs, so if he gives you a thumbs up, I'd consider that pretty high praise.

Don't worry about your woodworking skills. -He's seen my skills, so he's already seen the worst...

> Some may think it's tuned a bit low,
> but after listening to some pretty dynamic
> program material, I'm concluding that the
> low tune has merits.

I've experienced, and touted the benefits of low tuning for some time. Not the loudest bass, but it can provide the benefits of lower extension and yet have that tight 'sealed' sound. Perhaps because it emulates a low Q sealed roll off initially, and maybe due to the GD being pushed down so low.

C

[jordanroy]

Pete! I got some good devellopements. Can you give me a call when you have a second?

Jordan

819-562-9879
or
819-674-1151

[Pete Schumacher ®]

> Pete! I got some good devellopements. Can
> you give me a call when you have a second?

> Jordan

> 819-562-9879
> or
> 819-674-1151

It'll have to wait until later tonight.

Call me at home around 8:00?

[jordanroy]

> It'll have to wait until later tonight.

> Call me at home around 8:00?

Okay!

Jordan

[killerkowalczyk]

I was planning on building a pair of speakers after xmas using 6 6.5" Dayton classics, 3db more efficiency than the Aluminum drivers.

[Pete Schumacher ®]

> I was planning on building a pair of
> speakers after xmas using 6 6.5" Dayton
> classics, 3db more efficiency than the
> Aluminum drivers.

I can appreciate that. You'll be able to drive them to their limits with half the power. Can't wait to see what you come up with! I'm anxious to get started on my 6-woofer version. Cabinetry is relatively cheap so I just need a certain mid and tweet to make this an all Dayton effort . . . ;-)

[Deward Hastings]

I'm using the DC-160 with the RS52/ND20 combo for a set of surrounds I'm building (but just one per box (g)). Crossing at 750-800 Hz there shouldn't be any cone problems. But I'd love to see distortion plots taken in the same fashion as Zaph has used for the other 6 1/2 inch drivers he's tested . . .

got the parts (most of them, anyway, the crossover design keeps changing) . . . now have to find the time . . .