By the way, I played a bit with a glass panel I found in the basement. It was once a cover of a side table. It is 6mm thick and 60 cm x 40 cm sheet with curved corners. The sound was not good with the exciter at 2/5th, 3/5th position, or any other position, or on the edge. Too sharp. Took my EPS sheet out (70cm x 40cm x 2cm) to compare. That I know it works quite well with two exciters (two stereo channels) on edge, so this time I pasted the exciters 14cm from both the long edges in the middle line. 2/5th, 3/5th doesn't matter when the 2 stereo channels attached.
When held tightly from the top, that is, somewhat pushed to the table, I felt nice bass sounds coming out of it. I even managed to stand in line with it, and the sound was practically same. Then I placed the on the table with Exciters isolated from the table by cork supports for glasses, and let it play. Then, I placed my hands over the area where the exciters were, the sound became fuller, with sort of more bass. I was thinking something heavy to put over the exciters, I thought I'd put the glass sheet over it.
The sound became somewhat nicer, fuller. This glass sheet is quite heavy. Listened to some instrumental music, some classical music and some pop, jazz etc. More cork supports, better the sound. Maybe, if this was inside a back-box, it might give an even better sound. I still wanted to check how a thin glass sheet would do. Someone promised me a 2mm or 3 mm glass sheet next week. Well, when you get the experiment bug, it's hard. I suddenly remembered we have those Ikea tempered opal glass plates. First, I pasted the exciter in the middle, but the sound is nothing much to speak about, but then, I held it vertically over the exciter without its aluminium plate, only over the spider plate/frog legs.
The Ikea Oftast plate could touch the exciter only on one point, which is interesting, the point transfer of audio vibrations. The sound actually is quite nice. I did all that while France beat Denmark. Now, Argentina is having a hard time with Mexico. Edit: Messi just scored a goal!
When held tightly from the top, that is, somewhat pushed to the table, I felt nice bass sounds coming out of it. I even managed to stand in line with it, and the sound was practically same. Then I placed the on the table with Exciters isolated from the table by cork supports for glasses, and let it play. Then, I placed my hands over the area where the exciters were, the sound became fuller, with sort of more bass. I was thinking something heavy to put over the exciters, I thought I'd put the glass sheet over it.
The sound became somewhat nicer, fuller. This glass sheet is quite heavy. Listened to some instrumental music, some classical music and some pop, jazz etc. More cork supports, better the sound. Maybe, if this was inside a back-box, it might give an even better sound. I still wanted to check how a thin glass sheet would do. Someone promised me a 2mm or 3 mm glass sheet next week. Well, when you get the experiment bug, it's hard. I suddenly remembered we have those Ikea tempered opal glass plates. First, I pasted the exciter in the middle, but the sound is nothing much to speak about, but then, I held it vertically over the exciter without its aluminium plate, only over the spider plate/frog legs.
The Ikea Oftast plate could touch the exciter only on one point, which is interesting, the point transfer of audio vibrations. The sound actually is quite nice. I did all that while France beat Denmark. Now, Argentina is having a hard time with Mexico. Edit: Messi just scored a goal!
I slept over the matter. I think any DIY exciters/transducers are just DIY stuff, just to experiment on, and nothing else, crude affairs. If anyone wants a long-lasting DML product, one has to make his own transducer from an existing known commercial speaker driver. Of course, that too is DIY product, at least the commercial speaker driver had some good R&D in that company. Here's an interesting article on Bertagni speakers, restoration and also on polystyrene.
On the matter of wall, ceiling mounted DML speakers (Amina), what they plaster could not be the DML surface, the vibrating surface, but a surface in between, which doesn't touch the DML panel. Otherwise, in time, the plaster joints would crack, gypsum being a brittle element after setting.
Well, no experiments today and until next Friday. Hope to find some thin sheets of different material, best if I don't have to pay for them.
Found some Bertagnis at ebay, if anyone wants to dismantle them.
On the matter of wall, ceiling mounted DML speakers (Amina), what they plaster could not be the DML surface, the vibrating surface, but a surface in between, which doesn't touch the DML panel. Otherwise, in time, the plaster joints would crack, gypsum being a brittle element after setting.
Well, no experiments today and until next Friday. Hope to find some thin sheets of different material, best if I don't have to pay for them.
Found some Bertagnis at ebay, if anyone wants to dismantle them.
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Steve -
My aluminum panels measure 70 3/4" x 28 1/4".
I have the exciters (Thrusters) mounted in center of the panels (although I think one of them might be off an inch or so).
I placed the exciters pretty casually when I first made them given I had found the panels on the street and had only made a small investment in the exciters. I didn't imagine how they would capture my audio imagination.
They sounded so good to me and everyone I brought over to hear them compared to a whole range of other speakers we had listened to in my loft including:
Strathern ribbons with Magnepan Tympani 4 base panels (I liked these a lot)
Martin Logan reQuests
Dahlquist (modified)
PureAudioConcepts 15" Trios w/the Beyma AMT TPL150H Horn Ribbon Planar drivers
I never got around to trying other positions.
The new way I place the DMLs makes it easier to experiment with moving the exciters.
Suggestions welcomed.
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Hi Andreas,
I don't understand what I'm looking at in your picture. Can you explain?
Erc
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I did.
A fancy Italian kitchen store, Valcucine, across the street from where I live in lower Manhattan, had used them as cabinet doors. When they changed the display they had set them outside of the store to dispose of them in a dumpster. I just happened to walk by, saw the panels, and brought them home.
I had no plans for them at the time, they just looked sexy. I did hide them from my wife for a couple of years until I came across this discussion thread and decided to make DMLs out of them.
- Andreas
I consolidated my two audio systems into one.
I turned my aluminum DML panels on their sides and mounted them on the wall behind the TV (base 4” from wall, tops 3/8”) tilted (under the speculation it might help prevent standing waves).
Because they sit several inches behind the TV I don’t notice any degradation in sound quality from my earlier setup.
Again, speculation, the reflections just bounce around and get to my ears.
I plan to do measurements later to day to optimize the SPL curves for the room and between the DML panels and the subwoofers.
I mentioned in an earlier post that I also stuck an exciter (Thruster) on the back of the LG TV’s OLED panel, which amazingly functions as a center channel speaker and has done much to improve the spoken voices on video and films.
- Andreas
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I used to watch what people throw away, but I didn't go about much last year. Anyway, my wife tells me why not use glass from old picture frames. The EPS gives quite good sound, but is pretty brittle stuff, can break anytime. Maybe, I'd try to paste the glass over the EPS sheet. Must think about this until next weekend. Maybe some mental bulbs might light up.
The Stratherns?
Yes. I learned about them from a group of audiophile DIYers out in Dayton, Ohio in the early 1980s.
A surprising hot bed of audio DIYers. Lot's of aeronautical engineers from Wright Patterson Airfare Base's development lab that liked to do home projects.
Dayton Audio and Parts Express emerged from the milieux.
Around that time Speaker Builder magazine had profiled them and - if memory serves - suggested some modifications to improve them even beyond their already wonderful sound.
They did not have deep bass so all of us at the time tried matching them with various kinds of woofer and/or subwoofers. A couple of guys had built transmission line subs.
By pure luck, I purchased a pair of the Magnepan bass panels (two per channel), from I guy who had previously matched them with stacked Quads. I think I paid him him a couple of hundred dollars.
I mounted the Stratherns between the bass panels. They did shake the walls, but within the range of the system's operation, their sound and musicality impressed every one that heard them.
I powered them with a pair of stereo Nelson Pass designed A40s.
The system would very much have benefited from what we have now in DSP and digital source material.
The guy that I think later founded Madisound had some of the ribbons and I also bought some crossover components from him.
- Andreas
Thanks Christian.
I tried an "unsealed" enclosure two months ago, with results similar to figure 5 you posted.
I'll have to try a sealed enclosure to see if I can get an effect more like figure 27a.
But I do wonder if the sealed enclosure approach is more applicable to a low aspect ratio panel, than for the the high aspect ratio panels I have been successful with lately, which already have good output down to their fundamental frequency.
Eric
Ahh, that's it Steve.
I thought the picture was showing how his new arrangement made it easier for Andreas to change his exciter position. But that wasn't what he was showing at all.
Ribbon tweeters and the like are off my radar screen. Plywood panels with the DEAX25FHE-4 typically go up to 10 kHz or more, and I don't hear anything significantly higher than 12 kHz, (like for most of us closing in on 60 years or beyond), so adding a tweeter would be only for the benefit of my children!
Eric
I wonder if Ammos licensed this patent? Seems like they might be infringing otherwise. At least if they are selling anything.
Eric
I never really understood the NXT patent, as the panels are basically sounding boards, which have been around for hundreds of years.
And as speakers for about 100 years ,with many patents.
It seems to me to be more about naming it DML ,and about the software that was leased ,which predicted the panel response?
You could not get the software without the lease ,if I remember correctly?
I presume tectonic owns this now?
But I presume this is very old and out of date now.?
Are there new versions that Eric and others are using?
Steve.
And as speakers for about 100 years ,with many patents.
It seems to me to be more about naming it DML ,and about the software that was leased ,which predicted the panel response?
You could not get the software without the lease ,if I remember correctly?
I presume tectonic owns this now?
But I presume this is very old and out of date now.?
Are there new versions that Eric and others are using?
Steve.
An inventor can combine earlier "art" and even patents still in effect when creating something new (novel) that solves problems that experts in the field of the patent have failed to solve otherwise.
I knew the woman, who, as a teenager, had an internship at Proctor & Gamble. As the story came to me, the company sent a group of kids to Washington one summer to search for things in the archives of the US Patent & Trademark Office that P&G could use. This happened long before a computer database of patents.
This teenager came across two patents:
One a kind of flimsy Gortex like material that you could pour water through one side but not the other, but far too flimsy to make anything practical.
The second a material that absorbed thousands of times in weight of water.
In the moment, she took each patent in one of her hands, put her hands together, and invented Pampers.