A Study of DMLs as a Full Range Speaker

Steve,
Note that they actually report two different results for Fs: 40 Hz under the heading "Magnet" and 312 Hz under the heading "Coil". I suspect strongly that they got the "Magnet" result by holding the voice coil fixed and letting the magnet move freely, while the "Coil" result they got by fixing the magnet and letting the voice coil move freely.
I get similar results when I test the Dayton exciters those two ways. For example, the plots below shows my two tests on a DAEX25VT-4, where the Fs (impedance peak) is around 36 Hz with the magnet free, and 213 hz with the voice coil free.
Interestingly, Dayton Audio specs only ever report the higher (voice coil free) result. But my own experience is that the lower (magnet free) result is more meaningful as an indicator of how low it's possible to go with a particular exciter. For example, (with the right panel and mounting) I can definitely get strong SPL output down to 50 Hz (maybe less) with the VT-4, which is a lot closer to 36 hz than it is to 213 Hz.
Eric
Doh! I appear to be the echo in the room. 🤦‍♂️
 
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Greetings everyone, it's been a while. Nice to see the masters of the DML universe still posting. After a few months of doing other things, I've returned to the home audio effort. I've been using my panels quite a bit and they sound just as good as they did six months ago -- since mine have 4 exciters each in their own panel, if one were to lag I'd know it. So, I'm still a huge fan of Dayton thrusters. On this recent round, I've been taking care of little things -- endless cabling / connectors / soldering, probably spent more on RCA/USB/speaker wire and components for my small setup than then amps and speakers.

As that effort is wrapping up, I'm looking to richen the main course. The question I don't believe I ever got around to asking you folks: what kind of amp works best with DML speakers? I have two class D 50x2 Fosi audio amps; one drives the LR top and the other drives LR bottom. I don't know how loud they go, seems like I still have plenty of room to crank beyond the loudest I've had them -- I've had them only to the point where I'm more worried about overloading the subs. So quantity isn't an issue for now, but as good as I think they sound, could I do better?

I've considered trying out those small tube amps, or getting a class A/B, upgrading op-amps, maybe a real pre-amp (I use my Steinberg audio interface)? What do you guys think?
 
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...
I've built DMLs with 3/32" aircraft basswood ply, 24" x 24" & 12x12" ... they sound good! (still need sub). But I'm struggling to find the right support structure -- I'd like to keep them open like Spedge's but this means a hanging installation, which isn't ideal for me.
1700421868837.png

Abstracta frames, provide a number of mounting options including hanging or gentle clamping. Search for my earlier discussion.
 
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The framework of this DML seems a little thin
Does the frame need fixing or adding weight or making it stronger?
But the overall look is simple and clean
Very comfortable feeling
The Abstracta, https://www.abstracta.com/ system uses 1/2" diameter steel tubing with zinc connectors. Very strong indeed. I considered filling the tubes with sand and epoxying the connectors, but these things sounded so good I never bothered to do it.
 
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Hello Steve
+ @monosuna
I am in an updating phase of the history file... Have a look to 7067, 7111.
@aagas : any change since that?
Christian
Hi aagas.
I don't remember seeing these panels before ?
What are the panels made from?
Steve.
I fiddled with different mounting things, but all of them worked fine acoustically. 7111 pretty well captured the effort.

3mm birch plywood. At some point a gave them a light wash of white paint. Didn't seem to change the overall impression of the sound much. They just seemed to sound like the instruments playing through them.
 
... The question I don't believe I ever got around to asking you folks: what kind of amp works best with DML speakers? I have two class D 50x2 Fosi audio amps; one drives the LR top and the other drives LR bottom. I don't know how loud they go, seems like I still have plenty of room to crank beyond the loudest I've had them -- I've had them only to the point where I'm more worried about overloading the subs. So quantity isn't an issue for now, but as good as I think they sound, could I do better?

I've considered trying out those small tube amps, or getting a class A/B, upgrading op-amps, maybe a real pre-amp (I use my Steinberg audio interface)? What do you guys think?
A purely subjective reply...

I've had the privilege and delight of having had some great amplifiers over the decades and having had access to great amplifiers - tubes, solid-state, super high end, and experimental ones. Of all these I had a particular affinity for the Pass A40s ;-)

I could (or at least I believed I could) hear real differences between the amps.

I also could (or at least I believed I could) hear real differences between vinyl, CDs, DVDs, tape, et al. Same with the advent of different digital formats, cables, speaker wire, and isolation tweaks.

Living with DMLs has changed all of these things for me. In my experience, the quality and realism of the kind of DMLs developed and discussed in this forum, so far exceeds those small differences between all that other stuff, that their differences just don't seem to matter so much if at all.

I find my DMLs (and all of the several versions I've assembled) very forgiving of amplification. I use Hypex amps to run my primary system, but only because I had them from a previous system.

I've run my panels on cheap amps my kids had. They still sounded great - engaging- musical!

Not certain what I'd try if I had to come up with new amps, but I don't think I'd splurge on anything fancy.
 
what about crossovers? Anybody use crossovers for their DMLs? I tried some 200hz a while back but thought it was cutting out too much. But there don't seem to be a lot of passive options. I've considered getting the Rolls 2-way crossover (as I've literally not found any other option) but curious what others are doing.
 
When I finally get my (dammed) back-ordered parts & tool to start my DML project,
I will be adding a woofer & super-tweeter. This means I will be building a crossover.
I'll be using a spectrum analyzer & microphone to determine the crossover design.
I wish I could tell you more.
Could you please tell me more about the "Rolls 2-way crossover"? I'm interested 🙂
 
Thanks for that,
I didn't realize you were talking about active crossover & bi-amping.
It looks like a nice product + made in USA.
I was amazed when I got my old Parts Express catalogue just how low cost things were in USD($).
Here in Australia all those products cost so much more.
I'm going to look at other Rolls products - out of interest.
( my crossover is going to be passive )
For fine-tuning, I'm going to use an analogue Yamaha graphic equalizer.
 
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A purely subjective reply...

I've had the privilege and delight of having had some great amplifiers over the decades and having had access to great amplifiers - tubes, solid-state, super high end, and experimental ones. Of all these I had a particular affinity for the Pass A40s ;-)

I could (or at least I believed I could) hear real differences between the amps.

I also could (or at least I believed I could) hear real differences between vinyl, CDs, DVDs, tape, et al. Same with the advent of different digital formats, cables, speaker wire, and isolation tweaks.

Living with DMLs has changed all of these things for me. In my experience, the quality and realism of the kind of DMLs developed and discussed in this forum, so far exceeds those small differences between all that other stuff, that their differences just don't seem to matter so much if at all.

I find my DMLs (and all of the several versions I've assembled) very forgiving of amplification. I use Hypex amps to run my primary system, but only because I had them from a previous system.

I've run my panels on cheap amps my kids had. They still sounded great - engaging- musical!

Not certain what I'd try if I had to come up with new amps, but I don't think I'd splurge on anything fancy.
Hi aagas.
I totally agree with these comments, I have had these exact experiences.
I used to play around with all sorts of amps wires CD players, you name it.
Now whatever I plug into my panels sounds fantastic.
Even my very cheap surround amp in my living room.
They produce such realistic sounds that I have not worried about cabling, amps and such things.
When instruments and sounds , sound so realistic, what more could you possibly want.
I used to try everything to squeeze just a little more atmosphere and detail.
But since I first heard dml , I have not felt the need to try and make minute changes to equipment , as the sound of dml is like night and day compared to other types of sound producers.
If I ever stop making different panels ,I am sure I will probably start thinking of other ways to improve the sound again.
But the system sounds so good I can't see that happening very soon.
As you say , those things only make minor changes that aren't that important, to me that is 😃
Steve.