DML/open baffle for pro sound use

Gregory Roig · « **on:** 29 Oct 2015, 01:13 pm »

Hey OB folks,
I want to design and build some DMLs for pro sound reinforcement. The ones available (Tectonic Audio and others?) are way too expensive for me to afford. Anyone know of some others at a reasonable cost?
Any tech knowledge to help with this build would be greatly appreciated. General parameters are:
1) It must be able to play loud AND accurately >94 dB spl 1w@1m hopefully...
2) Portability is helpful; size up to 6' x 4'
Thanks in advance for the help.

Odal3 · « **Reply #1 on:** 30 Oct 2015, 03:16 am »

Tell us more how you will use them?

One challenge vs the in-home will be to make them more durable. The EPS/XPS foam ones are very fragile so you probably will need to look for other material if you plan to move them around a lot or come up with a nice protective frame/enclosure (like the tectonic)

Gregory Roig · « **Reply #2 on:** 30 Oct 2015, 12:02 pm »

Sedge and Odal3,
Thanks for the responses. I know this site is more for home audiophiles and such but you seem to be the only site discussing DML design and building. Because of durability they will probably have to be plywood. Used for P.A. with sub woofer so FR of 150 or so to maybe 15kHz.
Sensitivity of about 95dB or greater and power handling above 100 watts. Desired SPL of 120 dB @ 1W/!M.
Those are the goals. Hope y'all can help me build it!

FullRangeMan · « **Reply #3 on:** 30 Oct 2015, 12:15 pm »

Quote from: Gregory Roig on 29 Oct 2015, 01:13 pm

Hey OB folks,
I want to design and build some DMLs for pro sound reinforcement. The ones available (Tectonic Audio and others?) are way too expensive for me to afford. Anyone know of some others at a reasonable cost?
Any tech knowledge to help with this build would be greatly appreciated. General parameters are:
1) It must be able to play loud AND accurately >94 dB spl 1w@1m hopefully...
2) Portability is helpful; size up to 6' x 4'
Thanks in advance for the help.

After so many years NXT speakers are yet rare in Hi-FI and pro-audio.
To do such panel speaker with just 1 exciter you will need a expensive pgm to calc all variables, in the 90s it priced $5K.

Also some years ago nor even the chinese manufacturers of the exciters were allow selling these devices by prohibition of NXT UK.
There is a long thread about multiple exciters:
http://www.audiocircle.com/index.php?topic=70541.0
Good luck.

Gregory Roig · « **Reply #4 on:** 30 Oct 2015, 12:31 pm »

Yes. I started following that post. Sorry to hear Zygadr passeed in January. Did he post any pics of his builds?
Also, go to Tectonic Audio to see their large DML panels. These are the inspiration for what I am hoping to do. They seem to have everything I need (high resistance to feedback, wide dispersion, low drop-off front to back, etc.) EXCEPT affordable price point. Thus a DIY version...

FullRangeMan · « **Reply #5 on:** 30 Oct 2015, 12:56 pm »

Oh I sorry to know Zygadr passed away, he was a great DIYer.
RIP

Yes he post various pictures, Richard even goes to his home in Australia listen the panel and his 211 amp.

SMT you must get the exciters before the other parts.
This Tectonic panel are strange to hi-fi, they are not OB/Dipoles.
Just suited to pro audio.

Odal3 · « **Reply #6 on:** 30 Oct 2015, 04:03 pm »

I think it's definetely doable without expensive software programs, etc by using your ears and frequency measurements. When creating music it doesn't have to be flat all the way and in fact a unique sound can sometimes be preferred. So no need to be super sensitive on how to hang the panels etc which is often the problem when using it in home application where trying to optimize frequency response. Plus, if you have other pro audio toys you likely have equalizer either in the rack or via software.

The tectonic panels consists of 1 to 2 plates per speaker depending on model with a ribbon crossed around 7,000 (guessing here bases on specs.) Not sure about how many exciters and ratings for the exciters themselves but looking at the specs it shows recommended amp power rating to be 400 at 8 ohm for the half panel model and 800 W at 4 ohm for the full panel one which suggests that the exciters in the panels are more powerful than the ones you can buy from parts express.

If you look at the mechanical drawings at tectonics site you will see that they have completely enclosed the panels and surround them with plastic (?) case and metal wire mesh combined with a neat hanging system. You can do something similar in wood too. But first and foremost I recommend to just get a panel up and running as a test to see if you even like it.Get a few of the more powerful exciters from parts expresss (40W ) and follow the instructions from the big tread. Try both one and several exciters on the panel. A good starting point is using the monacor positions. For extra db you may need to run multiple panels or multiple exciters on the same panel. I like the sound of birch panel the best with the exception of loosing some of the air on the HF. The wood panels doesn't play as loud as the foam panels so I recommend that you try both to get a feel for what you like.

Btw: Tectonic is probably using the ribbon to get more HF at a distance, but you may not need it in your application so start with running them full panel.

The panel speakers are exceptionally good at acoustic type of instruments such as guitar, piano, etc

Btw if you look through the long DML thread you will see pics where one person set it up in a church.

Keep us posted how it goes

Gregory Roig · « **Reply #7 on:** 30 Oct 2015, 04:27 pm »

Thanks for good info. Anybody tried carbon fiber and/or graphite-kevlar? Hollow core luan doors? I'm totally new at this so forgive me if I seem to be asking uninformed questions. Just trying to get a feel for this subject.

Gregory Roig · « **Reply #8 on:** 30 Oct 2015, 07:31 pm »

Odal 3,
Where did you find mechanical drawings at the Tectonic Audio site? I was not able to find them...

Odal3 · « **Reply #9 on:** 30 Oct 2015, 08:11 pm »

It's only the exterior dim for installation purposes. See the product pages. Here's the link to the full panel one
http://cdn2.hubspot.net/hubfs/449794/TectonicPL12ConsolidatedLineDrawing1-10-14.pdf?t=1445583398947

sedge · « **Reply #10 on:** 1 Nov 2015, 03:29 pm »

Gregor
Following on from the questions on the nxt forum,are you thinking of a panel like the tectonics heavily protected and encased or are you thinking of a more simple stand alone robust type panel like the plywood.
Poly types of panel would need a lot of protection ,but would have a very high output from a small exciter.
Ply could work if a high power exciter type was used but as yet not tested by me,if anyone has, hope they will let us know,ordering from parts express to UK is expensive , so I will not be taking part in the testing of different units ,I do have some ideas but that's about as far as I can go,it's taken me about ten years or longer playing about with exciter panels to get the sound I want ,it's sad that Rob didn't find his ultimate panel ,but I know he has found some very good panels on the way, I haven't always agreed with him but his determination was amazing.
Respect.
Steve

Gregory Roig · « **Reply #11 on:** 1 Nov 2015, 08:53 pm »

If you think I can get a reasonably good sound with plywood and EQ that would obviously be the simplest solution. However, if the best results are with EPS or ??? then I would go to the trouble to make protective frames. I wonder how much softer the sensitivity of plywood is to other mediums. If it's a big enough difference it may actually be impractical to go with plywood considering the SPL I'm after.
What part of the U.K. are you from?

sedge · « **Reply #12 on:** 3 Nov 2015, 12:25 pm »

Gregor
I think the plywood sound already surpasses good,it is whether you can find an exciter to do the job of driving the panel to the db you want,also how well the panel will drive a large room,open space, and where the fr cancellations will be.
I will setup the panels again and listen to lots of different vocals and see how they sound, and will let you know what I think.May even try to get them outside and have a quick listen ,neighbours permitting.(when I get time)
There is at least one exciter I think might be interesting to try which if it worked would sort out a lot of problems, early days yet so I look forward to seeing which way you are going to go with this.
I live about 40 miles west of London.
Steve

Gregory Roig · « **Reply #13 on:** 4 Nov 2015, 02:19 am »

The most powerful exciter I can find is a 40 watt unit. Also, I have no knowledge of the ins and outs of multiple drivers, although perhaps an easier approach would be to make several 2 by 2 (feet) panels and combine them in a line array. I've heard about a really good sounding exciter from Parts Express but it is apparently fragile...

OB_Newbie · « **Reply #14 on:** 4 Nov 2015, 04:15 am »

Hello there fellas... long time no post! Been crazy in the last month plus but hope to be around a bit more now.

Greg, that was my review and other posts on PE TechTalk. The Dayton Audio "Ultra" exciter is indeed a fantastic sounding exciter... even unEQed it is excellent on smaller (24"x30") XPS panels. It is fragile as I have lost 3 exciters now... and I don't listen at high levels.

Been listening to a pair of the new "Dayton Audio DAEX32Q-4 Dual Steel Spring Balanced 32mm Exciter 40W 4 Ohm" and while I need to let them break in more and let the panel treatment harden/cure thus far I am not to excited (

) about the sound quality but I'm going to give them a few more days and will then measure and EQ the freq. response "flat" to see if the mid-range performance that I'm not happy with can be improved. It is fairly smooth sounding and can say it seems to be robust... heavy and built like a tank.

Reason I'm mentioning the new "Dual Steel Spring Balanced 32mm Exciter 40W" exciters is that they also have a 8 ohm version so 2 wired in parallel would handle a pretty impressive 80 watts with a typical 4 ohm load. While they may not sound as good as the Ultra or Thruster exciters they sure seem like they would take the abuse needed for Pro applications. I think the multiple panel array idea is solid approach to accomplish a high output DML system. I'd imagine EQing is an option so you would be able to implement multiple exciters per panel for improved power handing and output and EQ the high frequencies to compensate for the slight loss of HF due to multiple exciters per panel.

Would you run subwoofers or bass bins or planning an all DML system?

DML's are so incredibly lightweight... gives some options when it comes to mounting I would have to assume!

Cool project!!

Odal3 · « **Reply #15 on:** 4 Nov 2015, 05:12 am »

I was just about to ask if anyone had tried the new exciters. The 8 ohm one peaked my interest for the same reason you mention. OB_Newbie -Did you ever try the DAEX30 HEFS-4? Curious to see how others find them. To me they extend the HF better than the trusters but dont hit the bass as hard. But they peaks a bit so I need to get some eq on them. So no winner yet that is superior all away accross.

Btw it would be great if Parts expresss could add some more details on design goals / intention for the exciters. Feels a lot like guessing how they are described today.

Odal3 · « **Reply #16 on:** 4 Nov 2015, 05:17 am »

I broke 2 Ultras as well ... they sound ok on light foam panels but come up short on heavier wood panels.

Gregory Roig · « **Reply #17 on:** 4 Nov 2015, 02:19 pm »

Yes, I too wish that there was more info on DML construction.
Do any of you know much about the newer BMR (balanced mode radiators) (for sale at PE) which incorporate a combination of piston and DML technology. I can't seem to get an answer from PE nor Tectonic Elements about whether you can use multiples of these drivers and still have the benefits of a DML. Wondering if they're protecting their patented ideas and don't want DIYers to infringe on profits... I did find some pro sound panels from Carlsbro called NlightN. But since nxt rights were bought by Tectonic (Elements & Audio labs), every panel out there is no longer in production. Finding used ones is difficult since they are rare. The only ones you can get are in the $7000 range.
Also, anyone heard the Warfedale Loudpanels? Also out of production...
Lightspeed makes a panel designed for classroom enhancement, NXQ. Anyone heard these? $50-- price is right but how's the sound?
Hey, no worries...building my own.

OB_Newbie · « **Reply #18 on:** 4 Nov 2015, 07:17 pm »

Quote from: Odal3 on 4 Nov 2015, 05:12 am

I was just about to ask if anyone had tried the new exciters. The 8 ohm one peaked my interest for the same reason you mention. OB_Newbie -Did you ever try the DAEX30 HEFS-4? Curious to see how others find them. To me they extend the HF better than the trusters but dont hit the bass as hard. But they peaks a bit so I need to get some eq on them. So no winner yet that is superior all away accross.

Btw it would be great if Parts expresss could add some more details on design goals / intention for the exciters. Feels a lot like guessing how they are described today.

Hey Odal!
I have not tried the DAEX30HEFS-4 yet but really want to... its on my short list. I have the DAEX25FHE-4 and it too has very extended highs. Well, I can't say they it has extended highs from a freq. response. perspective that is markedly different but I can say it *sounds* bright and detailed to me. Almost too much so... I get more panel noise with this one. Seems to transfer more energy to the panel and I have to damp the panel unlike any other exciter I have. These would be better suited to your ply panels I assume due to that fact.

OB_Newbie · « **Reply #19 on:** 4 Nov 2015, 07:21 pm »

Quote from: Odal3 on 4 Nov 2015, 05:17 am

I broke 2 Ultras as well ... they sound ok on light foam panels but come up short on heavier wood panels.

Yeah, i didn't do enough to warn you guys on this one. With its floating motor, it doesn't transfer enough energy to the panel and will make larger excursions attempting to due so which will be the cause of its demise.

I have been listening to more exciters again recently and going back to the Ultra's was surprising again. They are EXCELLENT on light-weight panels... at least up to 24x30... a very large panel I am not sure.