Probably a good idea :'D
It's an uncanny listening experience, the sound feels like it's coming from deep within the walls and it's soundstage is pretty trippy too. General overall tone is warm and relaxed, perhaps a little muted even. But modifications to the crossover and amplification are planned.
This music came on playing pokemon the other day and it was just enamouring to hear from a wall of sound. YouTube
My dml hybrids in the spirit of the 521 for sub $500
Hi everyone.
New member. My experience with dmls is 4x4 ft home store sande plywood with two Dayton 25mm drivers in parallel mounted 2/5ths hung off the heating pipes in my basement. Running them on the 20 watt class d Lenapi which is working quite well. Full range caused serious resonance and rumbling. But crossed over passively at 2k stopped all resonance in the range of my hearing. I added a few small sub mid bass ported boxes right next to them also being driven on the same 20 watt Lenapi and it rocks. Soundstage is huge. I am never going back. Happy to demo anyone this design on a FaceTime.
Tonewood just sounds so much more rational than foam. I am sure I can make the panels 2x2 and get a similar effect as the sound dispersion
Now my next idea is to combine dmls with open baffle 15s. Either In a h frame or 2 10 s in a w frame al la the 521. Crossover around 400 to 800. I have checked out the eminence alpha 15s but I think I can try goldwoods also.
I also plan to bi amp and use a minidsp hd or the Dayton dsp to optimize the crossover.
So think about this design from a bang for the buck perspective and simplicity of assembly complexity. Total parts cost is sub. 500 including amplification and signal processing. Yes it’s not a 521 but in the spirit of the 521.
Hi everyone.
New member. My experience with dmls is 4x4 ft home store sande plywood with two Dayton 25mm drivers in parallel mounted 2/5ths hung off the heating pipes in my basement. Running them on the 20 watt class d Lenapi which is working quite well. Full range caused serious resonance and rumbling. But crossed over passively at 2k stopped all resonance in the range of my hearing. I added a few small sub mid bass ported boxes right next to them also being driven on the same 20 watt Lenapi and it rocks. Soundstage is huge. I am never going back. Happy to demo anyone this design on a FaceTime.
Tonewood just sounds so much more rational than foam. I am sure I can make the panels 2x2 and get a similar effect as the sound dispersion
Now my next idea is to combine dmls with open baffle 15s. Either In a h frame or 2 10 s in a w frame al la the 521. Crossover around 400 to 800. I have checked out the eminence alpha 15s but I think I can try goldwoods also.
I also plan to bi amp and use a minidsp hd or the Dayton dsp to optimize the crossover.
So think about this design from a bang for the buck perspective and simplicity of assembly complexity. Total parts cost is sub. 500 including amplification and signal processing. Yes it’s not a 521 but in the spirit of the 521.
Bob,
Like my question about the 521s, the answer is probably obvious to all but me. But are you using the panels only above 2k, or below 2k? For me it seems a strange place to cross, because I'm finding that my panels cover about 200 to 10k very well, so I'm curious why you would cross at 2k (in either direction).
Eric
Tall Story
So my brother came round a few weeks back and was blown away by my DMLs. He was so impressed he asked me if I could build him a pair, the only snag being his front room is long and narrow with a lot of windows so there is now space for free hanging panels.
So I have spent some time building floor standers for him and it has been a very interesting experiment. The pictures attached show the first test panel and frame. The panel is long and thin, 1160 by 300, which breaks all the rules. The panel is 4mm ply and the frame is walnut. The panel is attached to the frame using industrial double sided foam tape.
Here are my key learns.
1. A long and thin panel works very well. Despite deviating from the recommended 1:1.618 ratio they have a fine sound with all the normal DML virtues and one surprise…
2. Bass! I get a good output down to 40hz, big fat meaty dollops of bass. Weird!
3. The best exciter position is very different to more conventional panels. I discovered the sweet spot using Veleric’s recommended method supporting the panel horizontally and moving the exciter about until you get the best sound ( Post #645). Thank you Eric, the method works very well!
4. I didn’t bother rounding the panel corners this time. It didn’t seem to matter.
Please engage your numpty detector at this point, what follows is highly speculative
I think the major variable for the better bass output is probably the mounting but it’s not straight forward.
If you read the literature you should get a lower fo for a panel with no edge damping or clamping. A corner clamped panel has a higher fo, and an edge clamped panel has the highest fo.
But, as others have already discovered ( DMLBES, Veleric etc etc) some edge damping increases bass output on DML panels.
I found greater output when the panel was lightly coupled to the frame, literally its own mass plus the exciter. I had to damp the exciter with my finger to stop it moving, but, when I Ioaded it with a book as a reaction mass ( Heavy book in all senses! ) the overall output dropped somewhat. There is obviously a balance to be struck. I am guessing that the ideal is an edge loading that gives very good rotational freedom but also good damping. I still don’t know why this arrangement gives a better result that free edges, but it does on this panel.
The other obvious factor is the unusual panel ratio. Maybe the length allows recreating the bass notes , 1.16 meters is still small for bass, its the wavelength for 295.68hz and even allowing for 1/4 wave that’s still only 74hz. I was definitely getting 40hz and could get output at 30hz using a tone generator.
Adding to the puzzle is that both my free hanging panels are also just over a meter on their longest axis, but bass output is BBC polite rather than JBL large, so that suggests its the frame and damping again. I will try adding some damping to the edges of the free hanging panels, but I believe this has been covered and was rejected before. It might have been the Tech Ingredients crew? Puzzling.
I am still going to use a sub for this build as it will allow a higher SPL, my brother likes stadium rock, and they will still go deeper, he also like Joy Division. But for those who want to try a tall thin DML I am pretty certain you won’t be disappointed.
Hope this helps someone
Burnt
So my brother came round a few weeks back and was blown away by my DMLs. He was so impressed he asked me if I could build him a pair, the only snag being his front room is long and narrow with a lot of windows so there is now space for free hanging panels.
So I have spent some time building floor standers for him and it has been a very interesting experiment. The pictures attached show the first test panel and frame. The panel is long and thin, 1160 by 300, which breaks all the rules. The panel is 4mm ply and the frame is walnut. The panel is attached to the frame using industrial double sided foam tape.
Here are my key learns.
1. A long and thin panel works very well. Despite deviating from the recommended 1:1.618 ratio they have a fine sound with all the normal DML virtues and one surprise…
2. Bass! I get a good output down to 40hz, big fat meaty dollops of bass. Weird!
3. The best exciter position is very different to more conventional panels. I discovered the sweet spot using Veleric’s recommended method supporting the panel horizontally and moving the exciter about until you get the best sound ( Post #645). Thank you Eric, the method works very well!
4. I didn’t bother rounding the panel corners this time. It didn’t seem to matter.
Please engage your numpty detector at this point, what follows is highly speculative
I think the major variable for the better bass output is probably the mounting but it’s not straight forward.
If you read the literature you should get a lower fo for a panel with no edge damping or clamping. A corner clamped panel has a higher fo, and an edge clamped panel has the highest fo.
But, as others have already discovered ( DMLBES, Veleric etc etc) some edge damping increases bass output on DML panels.
I found greater output when the panel was lightly coupled to the frame, literally its own mass plus the exciter. I had to damp the exciter with my finger to stop it moving, but, when I Ioaded it with a book as a reaction mass ( Heavy book in all senses! ) the overall output dropped somewhat. There is obviously a balance to be struck. I am guessing that the ideal is an edge loading that gives very good rotational freedom but also good damping. I still don’t know why this arrangement gives a better result that free edges, but it does on this panel.
The other obvious factor is the unusual panel ratio. Maybe the length allows recreating the bass notes , 1.16 meters is still small for bass, its the wavelength for 295.68hz and even allowing for 1/4 wave that’s still only 74hz. I was definitely getting 40hz and could get output at 30hz using a tone generator.
Adding to the puzzle is that both my free hanging panels are also just over a meter on their longest axis, but bass output is BBC polite rather than JBL large, so that suggests its the frame and damping again. I will try adding some damping to the edges of the free hanging panels, but I believe this has been covered and was rejected before. It might have been the Tech Ingredients crew? Puzzling.
I am still going to use a sub for this build as it will allow a higher SPL, my brother likes stadium rock, and they will still go deeper, he also like Joy Division. But for those who want to try a tall thin DML I am pretty certain you won’t be disappointed.
Hope this helps someone
Burnt
Attachments
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Hi Burntcoil,
Nice work! Thanks for sharing with us and the cool surprise of meaty bass, the holy grail of DML's? I think it may be the fact that the major dimension is long so the panel is vibrating dominantly along its longitudinal axis. Imagine a rectangular panel that is 1.16m tall - it will have 40Hz bass, but since it is wider, the energy also goes to supporting, higher frequency modes. Now since the other modes are suppressed due to the tall aspect ratio, more energy is available to excite only the bass modes. This may indicate that we can play with aspect ratio to tune the relative bass/mids balance. Sort of a like a mechanical bass enhance EQ knob. Or maybe similar to old-style bass/treble adjustment in old school receivers.
Very exciting development! We are learning new things all the time and it seems we are far from close to finding and tweaking all there is out of DMLs.
I have some nice 1x2in pine framing material waiting for a tall skinny floor stander. Would suspending the panels by the corners using twine work? Or does it need some edge damping to not go crazy? What is your optimal exciter position in relative fraction of height and width?
Cheers,
X
Nice work! Thanks for sharing with us and the cool surprise of meaty bass, the holy grail of DML's? I think it may be the fact that the major dimension is long so the panel is vibrating dominantly along its longitudinal axis. Imagine a rectangular panel that is 1.16m tall - it will have 40Hz bass, but since it is wider, the energy also goes to supporting, higher frequency modes. Now since the other modes are suppressed due to the tall aspect ratio, more energy is available to excite only the bass modes. This may indicate that we can play with aspect ratio to tune the relative bass/mids balance. Sort of a like a mechanical bass enhance EQ knob. Or maybe similar to old-style bass/treble adjustment in old school receivers.
Very exciting development! We are learning new things all the time and it seems we are far from close to finding and tweaking all there is out of DMLs.
I have some nice 1x2in pine framing material waiting for a tall skinny floor stander. Would suspending the panels by the corners using twine work? Or does it need some edge damping to not go crazy? What is your optimal exciter position in relative fraction of height and width?
Cheers,
X
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@ Bob Johnson. Hi Bob and welcome.
I cross my panels over at 100hz to subs and get an excellent performance. I am also interested in why you chose 2k. Can you give us a bit more on the rumbling you got full range, its a first I think.
Burnt
Hi X, hope you are good.
The bass came as a bit of a surprise I must admit! As you know I have experimented with several panels now but this one has been the best bass performance to date. I like your description as a possible reason, it makes great sense, and also think the edge damping method might be helping by making the panel seem larger than it actually is by reducing the reflection you get from the edges. There is a lot in the literature about creating an infinite panel, thats the reason for the variable angle slots on the DML panels by Gobel. This is highly speculative on my part.
On exciter position I got there by experimenting using Veleric's method. The final position is 155mm from the longest edge and 677 from the smallest. On a 1160mm tall by 300mm wide panel this gives a weird and not very helpful factor of O.516 on the width and 0.583 on the longest which is not particularly rational. Move the exciter towards the edge and the sound loses bass and gains midrange, move the exciter away from the centerish position towards the top or bottom and again you lose bass and the sound becomes brighter. The conventional 2/5th spots which is where I started sounded great to begin with but it became very obvious they were not the best for this design.
At the moment I would use light damping. I used some thick foamed double sided tape. I think hanging from the corners without damping will make the panels 'buzz' if they contact the frame so you will probably need some.
Burnt
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Hi X
OK so I could not settle until I tried something. I took the second panel which I have not mounted, attached an exciter and 'suspended' it by holding it by my finger. No frame, no damping. I still got great bass. It's something to do with the ratio. Even more weird but easy for anyone to check out if they think, quite reasonably, that I am losing the plot.
Yrs ( entering ever deeper levels of confusion) Burnt
Tall Story
Burnt - thank you so much for sharing this great build. I think this is ground breaking stuff but at the same time confirming what others have reported. This build is really very encouraging for me for several reasons. Getting bass from such a relatively small panel, and confirming that tall and narrow panels can work well. Not just more (deeper) bass, but good punchy bass if I am correct? I absolutely love the dimensions of this panel - esthetically beautiful, WAF friendly and make such panels so much more practical for smaller rooms or houses. I also love the light plywood with the darker solid wood frame. Well done and keep us posted on further developments.
PS: Love the name of these panels - Tall Story.
Burnt - thank you so much for sharing this great build. I think this is ground breaking stuff but at the same time confirming what others have reported. This build is really very encouraging for me for several reasons. Getting bass from such a relatively small panel, and confirming that tall and narrow panels can work well. Not just more (deeper) bass, but good punchy bass if I am correct? I absolutely love the dimensions of this panel - esthetically beautiful, WAF friendly and make such panels so much more practical for smaller rooms or houses. I also love the light plywood with the darker solid wood frame. Well done and keep us posted on further developments.
PS: Love the name of these panels - Tall Story.
@Twocents.
Thank you, that is kind of you to say. It was very much an experiment in proportion to fit in a small space and I was surprised by how well it worked out. The bass performance was a big surprise and yes it has impact as well as depth. I need to do more testing on them and fine tuning and update here as I go.
For now I am very confident you will get a great sound with this form factor and a sub. I believe, but want to test more, that if you are happy with bass down to 40hz then they could be used as 'full range' , but I suggest you wait until I confirm that.
My son is a physicist and when he came home this evening I asked him about the bass and he is equally intrigued. He thinks it might be something to do with node density and he is going to model the nodes for these panels over the next couple of days as he knows the formula ( what a show off!) If that pans out I will post the result.
@ihan
Hi Ian, the tape was nothing special, just a thicker variant of foamed double sided I had in my stock. I will see if I can identify a source for you and post that.
The exciters are Dayton DAEX32EP-4 Thruster 32mm Exciter 40W 4 Ohm.
Details here
Dayton Audio - DAEX32EP-4 Thruster 32mm Exciter 40W 4 Ohm
Night all
Burnt
Thank you, that is kind of you to say. It was very much an experiment in proportion to fit in a small space and I was surprised by how well it worked out. The bass performance was a big surprise and yes it has impact as well as depth. I need to do more testing on them and fine tuning and update here as I go.
For now I am very confident you will get a great sound with this form factor and a sub. I believe, but want to test more, that if you are happy with bass down to 40hz then they could be used as 'full range' , but I suggest you wait until I confirm that.
My son is a physicist and when he came home this evening I asked him about the bass and he is equally intrigued. He thinks it might be something to do with node density and he is going to model the nodes for these panels over the next couple of days as he knows the formula ( what a show off!) If that pans out I will post the result.
@ihan
Hi Ian, the tape was nothing special, just a thicker variant of foamed double sided I had in my stock. I will see if I can identify a source for you and post that.
The exciters are Dayton DAEX32EP-4 Thruster 32mm Exciter 40W 4 Ohm.
Details here
Dayton Audio - DAEX32EP-4 Thruster 32mm Exciter 40W 4 Ohm
Night all
Burnt
That's why I always said bigger panels is not always better as there is a right size panel for that particular exciter as the exciter needs to saturate the panel. If you look at Magnepan and Martin logans there panels aren't that wide but they are tall. If you look at the podiums they are taller then they are wide. That's why like I said take techniques from proven loudspeaker designs that work.
Secondly like I said before the foam tape (damping) reduces the vibrations from escaping to the sides and keeps it in the panel so more volume including bass is increased because its more focused on the panel.
Third, instead of a book this is where the SPINE/SPLINE comes into play.
Edge damping also reduces unwanted resonance.
This is once again why I stress a frame and a spline.
Tech ingredients is just a beginner with beginner designs. He rejects damping or anything touching the panel because he says it reduces output. A slight reduction in output in exchange for better quality/sounding panels is worth it and a good compromise.
You seem to be on the right track now.
To bad yawl couldn't hear my panels, I would make yawl a believer. LOL
I played with most exciters and tried all kind of materials for the panels
And the most natural sounding by far and away was 3mm cardboard with
A coat of 50/50 mixed titebond wood glue and water applied 1 coat to both sides
Rolled on with 1/4 inch nap.
As for size that I settled with was 30 inches wide by 5 feet long
With the corners rounded over that really helps tame the highs,
The best sounding exciter I used was the Dayton Ultra,
They had great sound I feel I had really good bass down to at least 40hz
The do not need a frame I just used a few pieces of 1/2 inch thick poplar
About 1 inch wide by 4 inches long a these are put used like a clamp on upper left and
Right of the panel to suspend them just bring the wood pieces about a 1 1/2
Down over front and back of panel and then screw right thru the
Front piece of wood thru the cardboard grabbing and pulling the 2nd piece of wood tight
Against cardboard panel. Then put a small hole at top of wood and run some coated solid
14 gauge wire thru and then attach that to some eyebolts screwed into the ceiling.
I used a baffle step compensation it makes a huge difference in Bass output I settled on 1.5 MH 16 gauge iron core inductor with 5 ohm parallel.
Also there is a ratio for optimal mounting the Exciter
I think I have it in my files somewhere it is a Monacor article on it.
And the most natural sounding by far and away was 3mm cardboard with
A coat of 50/50 mixed titebond wood glue and water applied 1 coat to both sides
Rolled on with 1/4 inch nap.
As for size that I settled with was 30 inches wide by 5 feet long
With the corners rounded over that really helps tame the highs,
The best sounding exciter I used was the Dayton Ultra,
They had great sound I feel I had really good bass down to at least 40hz
The do not need a frame I just used a few pieces of 1/2 inch thick poplar
About 1 inch wide by 4 inches long a these are put used like a clamp on upper left and
Right of the panel to suspend them just bring the wood pieces about a 1 1/2
Down over front and back of panel and then screw right thru the
Front piece of wood thru the cardboard grabbing and pulling the 2nd piece of wood tight
Against cardboard panel. Then put a small hole at top of wood and run some coated solid
14 gauge wire thru and then attach that to some eyebolts screwed into the ceiling.
I used a baffle step compensation it makes a huge difference in Bass output I settled on 1.5 MH 16 gauge iron core inductor with 5 ohm parallel.
Also there is a ratio for optimal mounting the Exciter
I think I have it in my files somewhere it is a Monacor article on it.
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