DIY Flat Panel Speaker Love

[captainjack115]

Re: DIY Flat Panel Speaker Love

Heck, using the 8000 microphone with your RTA or software like REW is totally cool Jack. I use my OmniMic setup to dial in a "flat" response. The FR with XPS DML panels is not the smoothest freq. response in the world so any option that brings a smoother FR is all totally fair play in my opinion... how ever it happens!

Hmmmm... I recall someone mentioning a design of stretched Mylar diaphragm with a conventional voice coin attached. Interesting for sure but I wonder if it would really be classified as a DML... seems to me that this configuration would be more similar to an electrostatic or FR ribbon but driven from a single point?!? The panel needs to be rigid to be able to generate nodes across the panel.

Regardless, I'd love to hear his impressions of the stretched Mylar and what the FR looked like.

Cheers!
Rich

I've had a world of experience building electrostatic speakers.

One thing I've learned about ESL's, or any other stretched diapragm speaker for that matter is resonance, Plastic film will resonate like a drum if it's not damped.
Nobody ever plays Magnepans' without grill cloth for that very reason. They'd surely have a really nasty ring to them at their resonant frequency.
So this brings up an interesing point. Will having ridgity in one direction on the diaphagm be enough to qualify as a bona-fide DML plate? Surely when an exciter pulse hits at it's epicenter,
nodes will be generated across the surface. Ripples in a pool, if you will. It's going to need to be damped one way or another.

I'll have to call my friend on the phone and ask more questions on this technique. He did say that he measured extended high frequency response to the extreme edges of the panel.
That to me would suggest earmarks of typical DML behavior.

Many years ago I bought a speaker made of expanded foam, the voice coil and magnet were embedded within the molded foam. The difference between that design and an exciter driven DML was that the expanded foam speaker didn't drive through the foam, Only the edges connected to the foam panel through the voice coil, leaving the center to radiate into the listening space like a conventional speaker....................The sound?................Nothing to write home about!

Jack

[rmeinke]

Re: DIY Flat Panel Speaker Love

Whats up fellas, any activity on your DML panels??

I'm starting a wall mounted panel soon using the new Dayton Audio DAEX32Q-4 for single and considering a stacked array using the Dayton Audio DAEX32Q-8 for higher efficiency and output.

Hope to have something started soon!

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Hello everyone. Just about a month ago exciters never even crossed my mind until I bought a pair of Bertagni's SM100 speakers. If I am not mistaken these speakers use basically the same concept of exciters and they sound really great especially with VOICES. When playing some Diana Krall or Norah Jones it feels as if they are performing right there in my room with me LOL. To complete my system I am going to make a center and surround speakers using the Dayton exciters and employing the same concept/design as the Bertagni's SM100. Now I am a fan of flat panel speakers.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hello everyone. Just about a month ago exciters never even crossed my mind until I bought a pair of Bertagni's SM100 speakers. If I am not mistaken these speakers use basically the same concept of exciters and they sound really great especially with VOICES. When playing some Diana Krall or Norah Jones it feels as if they are performing right there in my room with me LOL. To complete my system I am going to make a center and surround speakers using the Dayton exciters and employing the same concept/design as the Bertagni's SM100. Now I am a fan of flat panel speakers.

Welcome to the DML thread! I have never heard the Bertagni's but do recall a thread where the owner rebuilt his panels using modern exciters and thought the sound was much improved over the original. I do not know the specifics of the mods or other details so take this statement as directional only... DML panels really so perform well with voice, acoustic, live, etc. type recordings. Fun to listen too!

[rmeinke]

Re: DIY Flat Panel Speaker Love

Thought this was an interesting post over at AC...

"Howdy all! Back from the nowhere zone. Unfortunately I haven't finished out the home theater yet, broken tools and family obligations and whatnot. I did however have time to let my neighbor have a listen to my front mains and center.

He is the sound tech for a well known Christian comedian. He is responsible for stage and studio sound. He sat there for about an hour just running through his reference playlist on my speakers. He said he couldn't believe how fast they were. Also said that his reference in the studio were $700 apiece and placed about 2 feet from either side of his head. He wanted to stay and listen longer but his wife told him they had to go lol. Kept saying that they were every bit as good as what he used in the studio without the fatigue. He said he would have no problem listening to them for hours."

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

I am planning on building a pair of DML panels using either the DAEX32Q-4 or the DAEX30HESF-4 and wiring them for a 8ohm load. If this build sounds even close or better then the bertagni's then I will base my whole 7.1 system on DML panel speakers.

When he says improved over the original I think I understand what he means. If you look at the back of the Bertagni's the magnets have 5 holes/vents. Each individual hole has a different sound/frequency. By covering up certain holes the sound of the speakers change, the more holes that are covered up the more accurate/foward the speaker sounds but it loses its wide open surround sound stage presence so I guess its all based on ones own personal preference. I found that covering just one of the 4 holes on the tweeter makes the sound of the bertagni's sound a little bit more foward and accurate without loosing too much of that wide open spacious sound. If you look at some of the dayton exciters the one's with the holes/vents in the back will probably have a more wide open surround sound effect and the ones without any vents in the back should sound more foward accurate is what I am speculating from tinkering with my bertagni speakers.

What I also noticed with the bertagni's is that with better quality recordings they sound awesome but with bad recordings they just sound awful. Even the quality of the amp/receiver can make a big difference. On my Yamaha receiver they sounded ok , on my Onkyo they sounded better but on my Harmon Kardon they sounded the best so I assume its similar to the flat panels.

I dont know about other flat panel speakers but the bertangi's do have decent amounts of bass, well at least decent enough for me on its own but if I need more bass well that is what a subwoofer is for lol.

I will be using foam since that is what the bertangni's use with some kind of coating on the front panel.

I also tried using one bertagni speaker as the center channel and it made my def tech clr 1000 sound like a transistor clock radio LOL.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey Unbiasedsound! I have a set of the DAEX32Q-4 just waiting to be mounted and compared to the other exciters I have in the collection. Been sick the last 3+ weeks and has really slowed me down but hoping to get some speaker time over the next week and will report back. Either ought to perform well but I still favor the DAEX32U-4 Ultra on lightweight panels such as XPS foam insulation board.

Its absolutely critical to sand off the XPS "skin" front and back and treat both sides with the 1:1 mixture of water and PVA glue... 2 coats per side. Use black ink with the water:PVA treatment to color the panels black... slight improvement over pink. Round the corners and edges as well.

I would recommend 1 exciter per panel, the magic is lost as you add exciters to the panel due to interference and cancellation of the adjacent exciter... especially at high frequencies. If you do choose to use multiples, strong consider the Monacor placement.

Funny you should mention quality recordings/audio chain; they do easily reveal differences in the entire audio chain. I have preferred a moded Sure class D amp board over my Sumo and Densen (Beat) and other vintage amps I have but recently purchased a Luxman LV-105u amp and all I can say is wow... very impressed... Luxman's reputation is well deserved indeed and the DML panels really made the amp improvement readily known. Amp differences usually take many hours of listening to my standard reference recordings that I know very, very well but the DMLs make it easy to id the Luxman. I listened to a 25 watt NAD a few months ago and, to be kind, it was quickly unplugged and placed back on the shelf. I have not spent much time comparing amps since I've been addicted to flat panel magic but when time allows I want to pull other amps out to get a better handle on this aspect of the panel performance. All indications seem to point to them as a looking glass into your audio chain.

DML have pretty surprising bass extension. Not totally sold on quality of the very lowest registers but a 2'x3' panel has very useful output to the 50Hz region without EQ.

I would also EQ them if at all possible... it is the largest improvement to date to make these panels shine. I'm listening to the 24"x30" panels right now with no EQ and they are hard edged through the midrange and make the female voice less listenable than when EQed flat and a slight dip from roughly 1000-2500Hz. Still enjoying them al naturale, but EQ is a really nice improvement.

Have to run but looking forward to hearing more of your DML plans!

Rich

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

I found this link its a very interesting read concerning flat panel designs, its seems that Bertagni was ahead of his times when it came to exciter technology.

http://web.archive.org/web/19990209060511/http://www.soundadvance.com/planarstory.html

[rmeinke]

Re: DIY Flat Panel Speaker Love

Thanks for the link... interesting reading for sure. I see a few of them on eBay so they must have sold a reasonable number of them. However I would bet that the treated 24" x 30: XPS panels with the Ultras sound better than the Bertagni. The piezoelectric supertweeter and multiple panels, in my opinion, bring complexity with little benefit.

Interesting observations from someone who restored a set of BERTAGNI SM-275...

"So after a week of futzing about, I hooked the Bertagnis up as the main speakers. Listened to some old master tapes, some HD Tracks, and some of my synthesized stuff. Wow! Do these things ever bring the performance to you! My reference for big open baffle speakers is my pair of original Quad electrostats. These image even better than the Quad 57s. Performers & instruments are solidly arrayed across the stage and don't move when I slide from one end of the sofa to the other. They are not quite as precise as Quads, having just a touch of resonance, like a bit of extra reverb - well below the music, but still there between notes. There is more bass. Wish they weren't so big - I'd leave 'em hooked up."

Later...
"In fact, they sound so good, I may have to move enough furniture to keep them set up!".


His observations about the "touch of resonance" is spot on. This aspect *really* annoyed me recently after listening to my KEF Q500's for several weeks and switching back to the panels. There is also more coloration from the XPS... a "hhhhhhhhaa" sound if you will... we need a more dense XPS/material. I was ready to denounce my love and devotion to the magic panels. But after a few listening sessions and one late night session the KEF's have been up stairs, covered up, and not hooked up for a few weeks again now.

They still bring the performers into the room like no other traditional speaker... despite the aspects above. This were unEQed panels so EQing will take them to another level and get rid of some FR/balance issues of a natural/unEQed panel.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Forgot to say as well, I picked up the super inexpensive Dayton Audio SUB-800 and high passed the DML panels at 150Hz via a Harrison Labs FMOD. Lightweight XPS panels and lightly suspended have uneven bass response; a large dip followed by a large peek (60Hz and 35Hz respectively). I normally EQ to minimize these FR anomalies but wanted to implement an inexpensive method (sticking with the low cost and easy build characteristics of the magic panels) that could be used to smooth the bass response and increase the power handling/output of the panels.

Lets be honest, for $99 I was expecting boom, thump and a general lack of detail but I am really surprised how well the Dayton sub performed against my KEF Q500's. The extension is about the same as the Q500 and maybe while not quite as articulate, they are very, very close honestly. DID NOT EXPECT THIS. After listening to open baffles for the last few years, I have become very sensitive to cabinet/port resonances and can say that the little sealed Dayton sub cabinet has less audible resonance than KEF's passive radiator assisted dual 5.25" woofers. Read the reviews of the KEF Q series - this is a very well executed commercial speaker with many very positive reviews... and a real bargain in commercial terms in my opinion and why I took the plunge (this is my first commercial speaker purchase since my first pair of MTX monkey coffins in the early 80's). I'm not pushing either of them to terribly high output levels and the game may change slightly in favor of the KEFs but don't expect them to play all that much louder or significantly cleaner than the Dayton. Really impressed for the money and they are built reasonable well and look as nice in the listening room as they do on the PE website.

Definitely highly recommended for anyone who wants to add a more traditional cone "slam" to a modest DML flat panel build. You might want to try the 100Hz FMODs but I'm surprised how nicely the panels and Dayton integrate in my large room crossed even as high as 150Hz.

Anyone listening to rock will likely prefer the Dayton covering bass duties below 100/150Hz.

[Kornbread]

Re: DIY Flat Panel Speaker Love

I've been really pressed for time lately so the short and skinny will have to do for now.

1" xps sanded and glued, 48x35~1.37 which is near the preferred dimensions,
1 dayton daex32ep-4 per panel,
Lightweight pine frame from 1x2's and 3's,
Panel held into place from all sides, frame lightly clamps onto panel edges

Have read this entire thread, the AC thread and other various posts of interest.

Short and sweet ... sounds bad. The echo, horn'y nasal sound is just b ... a ... d, no where near what I'd call good sounding. The xps has a sound when rapping it with the finger, the panels sound similar but trying to reproduce music ... well, it's just not good.

If work and schoolwork allow I plan on taking some measurements with REW before making any changes. It may be sometime around Thanksgiving or later before this happens. :(

I've read a lot about these and not giving up yet. The first changes will be cutting away some of the panel from the frame (aka the PE tech paper) letting the panel vibrate more freely and getting more measurements as things progresses. Also have some alternate panel materials that I think might just work. The material is easy to obtain and treat.

Sorry this post is so half baked but short on sleep and time.

OH ... don't breathe the dust from sanding the xps, it was a couple days before I could breathe right again.

[rmeinke]

Re: DIY Flat Panel Speaker Love

I've been really pressed for time lately so the short and skinny will have to do for now.

1" xps sanded and glued, 48x35~1.37 which is near the preferred dimensions,
1 dayton daex32ep-4 per panel,
Lightweight pine frame from 1x2's and 3's,
Panel held into place from all sides, frame lightly clamps onto panel edges

Have read this entire thread, the AC thread and other various posts of interest.

Short and sweet ... sounds bad. The echo, horn'y nasal sound is just b ... a ... d, no where near what I'd call good sounding. The xps has a sound when rapping it with the finger, the panels sound similar but trying to reproduce music ... well, it's just not good.

If work and schoolwork allow I plan on taking some measurements with REW before making any changes. It may be sometime around Thanksgiving or later before this happens. :(

I've read a lot about these and not giving up yet. The first changes will be cutting away some of the panel from the frame (aka the PE tech paper) letting the panel vibrate more freely and getting more measurements as things progresses. Also have some alternate panel materials that I think might just work. The material is easy to obtain and treat.

Sorry this post is so half baked but short on sleep and time.

OH ... don't breathe the dust from sanding the xps, it was a couple days before I could breathe right again.

Hi Kornbread, sorry to hear that the panels are not making good music for you!

How long have you listened to them? I got TERRIBLE panel self-noise the first hour+ with the Thrusters... this is the most likely cause given what I had previously experienced with the that particular exciter. Give it a good 30 hours to break in but I would also add that, in my experience, it takes a 10-15 minutes or so before it sounds good and best after an hour or so even after break in.... I attribute that to the steel spider. [edit - times are guesstimates, point... appears to improve over the listening session]

You might know that I favor light suspension... resting on a material that will absorb some of the panel vibration but not clamped in any way. Exciters are far more powerful than you would imagine and I'm afraid that you may be getting additional panel noise from the hard clamping as the contact with the panel, unless glued or secured in some way, is likely contributing some noise as it moves. XPS is soft and being a compliant material will move in relation to the "clamp" and can see how that might make noise. Also with the hard clamping to the frame, the frame itself becomes part of the DML and will have some output. It won't contribute much output or be the cause of the quality or lack there of but if its resting on a harder surface, it will vibrate and contribute noise.

Finally, and I am in the minority it seems, I am not a fan of large panels. My experience with large panels (at least with XPS) has not been good. While I would not say it is an echo as you describe, but I do get "drum" resonances with strong male voices (Muddy Water - Folk Singer for instance... very dynamic) which I could not get rid of and the feedback that I received from the large panel guys is that it is hard to eliminate all together. It was this experience that lead me to smaller panels and multiples if more output is needed. I find that smaller panels have less noise even with light suspension as the generated nodes can exit the small panel quickly. They sound better to me... more clarity and detail. Despite being small, my 14.5" x 12" (??) panels can fill a room... the soundstage is still just HUGE. I had them EQed flat down to approx. 110Hz and still no noise. Given the recent experience with even the el cheapo Dayton sub I would say that a small panel with a sub would be a really nice combination. I want to spend more time with the sub + flat panel combination but the early results are really good at low/reasonable output levels. If higher output is needed obviously we ought to look to the Dayton Reference or Ultimax series but at lower output levels the inexpensive 8" Dayton performs surprisingly well.

Any additional information about your panel construction and positioning of the panel/frame and what it might be resting on will help id the issue(s).

[Kornbread]

Re: DIY Flat Panel Speaker Love

Hi Kornbread, sorry to hear that the panels are not making good music for you!

How long have you listened to them? Not long one exciter quit after 15 minutes, the other has been running continuous at low volume for most of this week. I got TERRIBLE panel self-noise the first hour+ with the Thrusters... this is the most likely cause given what I had previously experienced with the that particular exciter. Give it a good 30 hours to break in but I would also add that, in my experience, it takes a 10-15 minutes or so before it sounds good and best after an hour or so even after break in.... I attribute that to the steel spider. [edit - times are guesstimates, point... appears to improve over the listening session]

You might know that I favor light suspension... resting on a material that will absorb some of the panel vibration but not clamped in any way. Exciters are far more powerful than you would imagine and I'm afraid that you may be getting additional panel noise from the hard clamping as the contact with the panel, unless glued or secured in some way, is likely contributing some noise as it moves. XPS is soft and being a compliant material will move in relation to the "clamp" and can see how that might make noise. Also with the hard clamping to the frame, the frame itself becomes part of the DML and will have some output. It won't contribute much output or be the cause of the quality or lack there of but if its resting on a harder surface, it will vibrate and contribute noise. The frame is screwed together trapping the panel between, little possibility of vibrating there. On the AC thread there was a guy early on that preferred his panels mounted solid, everyone seamed to ignore his posts, anyhow, when time allows, going to cut the panel edges to free it from the frame leaving only small amounts of the panel to anchor it to the frame, aka PE tech paper.

Finally, and I am in the minority it seems, I am not a fan of large panels. My experience with large panels (at least with XPS) has not been good. While I would not say it is an echo as you describe, but I do get "drum" resonances with strong male voices (Muddy Water - Folk Singer for instance... very dynamic) which I could not get rid of and the feedback that I received from the large panel guys is that it is hard to eliminate all together. It was this experience that lead me to smaller panels and multiples if more output is needed. I find that smaller panels have less noise even with light suspension as the generated nodes can exit the small panel quickly. They sound better to me... more clarity and detail. Despite being small, my 14.5" x 12" (??) panels can fill a room... the soundstage is still just HUGE. I had them EQed flat down to approx. 110Hz and still no noise. Given the recent experience with even the el cheapo Dayton sub I would say that a small panel with a sub would be a really nice combination. I want to spend more time with the sub + flat panel combination but the early results are really good at low/reasonable output levels. If higher output is needed obviously we ought to look to the Dayton Reference or Ultimax series but at lower output levels the inexpensive 8" Dayton performs surprisingly well. The 'drum' sound, yes, I could see it called that. I think we're hearing the same thing.

Any additional information about your panel construction and positioning of the panel/frame and what it might be resting on will help id the issue(s). Had planned to write-up the entire process, ran out of time. Will get up some pics and take measurements as time allows. Everyone in the household is in college and working full time = no play time.

xxxxxxxxxxxxxxxxxxx

[rmeinke]

Re: DIY Flat Panel Speaker Love

Pics would be very cool... I'm having a hard time conceptualizing exactly how the frame holds the panel. But if its XPS directly against wood with no dampening material between panel and frame... can see how that would sound less than optimal and explain the echo, nasal, honky sound. :(

For a quick fix and small time investment, I might try unscrewing the frame and putting foam weather tape (high density would be best in this case) between the frame and panel... that will be huge improvement if it is indeed XPS directly against wood and ought to take care of much of the sound quality issues.

With such a large panel I can imagine that you may still have to deal with potential of drum resonances even after adding the foam tape. If you do encounter this issue, I would steal a trick from the large Podium Sound DMLs and run a 1x2(?) spline across the length of the frame down the middle where you can then place what Podium calls "sound bridges" in a strategic location (or 2) to dampen the panel. These "sound bridges" could be a small piece of wood attached to the spline which protrude to touch and put pressure on the panel... these could have soft high density foam between the panel and bridge to damp the panel. Food for thought...

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Thanks for the link... interesting reading for sure. I see a few of them on eBay so they must have sold a reasonable number of them. However I would bet that the treated 24" x 30: XPS panels with the Ultras sound better than the Bertagni. The piezoelectric supertweeter and multiple panels, in my opinion, bring complexity with little benefit.

Interesting observations from someone who restored a set of BERTAGNI SM-275...

"So after a week of futzing about, I hooked the Bertagnis up as the main speakers. Listened to some old master tapes, some HD Tracks, and some of my synthesized stuff. Wow! Do these things ever bring the performance to you! My reference for big open baffle speakers is my pair of original Quad electrostats. These image even better than the Quad 57s. Performers & instruments are solidly arrayed across the stage and don't move when I slide from one end of the sofa to the other. They are not quite as precise as Quads, having just a touch of resonance, like a bit of extra reverb - well below the music, but still there between notes. There is more bass. Wish they weren't so big - I'd leave 'em hooked up."

Later...
"In fact, they sound so good, I may have to move enough furniture to keep them set up!".


His observations about the "touch of resonance" is spot on. This aspect *really* annoyed me recently after listening to my KEF Q500's for several weeks and switching back to the panels. There is also more coloration from the XPS... a "hhhhhhhhaa" sound if you will... we need a more dense XPS/material. I was ready to denounce my love and devotion to the magic panels. But after a few listening sessions and one late night session the KEF's have been up stairs, covered up, and not hooked up for a few weeks again now.

They still bring the performers into the room like no other traditional speaker... despite the aspects above. This were unEQed panels so EQing will take them to another level and get rid of some FR/balance issues of a natural/unEQed panel.

Since I havent bought the ultra exciter yet I cant really comment on the comparisons of which one sounds better. I can only compare of what I know logically. I wouldnt doubt with todays technological advances that the ultra exciter would sound better then bertagnis old exciters of the past, but what I would question is the design or building of the flat panels. I feel that Bertagnis understanding of how exciters work led them to many countless trial and error designs that lead to there ideal design which was then marketed to the general public. If you read the article bertagni custom molded and shaped his own foam to produce the best ideal sound by using grooves and channels. I feel this is the reason why bertagni can use more then one exciter and still have very good imaging. The only puzzling thing to me on the bigger models is that he used a piezo electric tweeter. On my sm100 which is one of the smaller models there is no piezoelectric tweeter and it sounds fine to me with enough treble/high end response that is why I dont know why in the larger models a piezoelectric tweeter was used.

I have also read that article where he fixes and upgrades a pair of sm 275s with the piezoelectric tweeter. From what Ive read he used the original exciters and in his opinion they sounded pretty good, just imagine if he had replaced the old original exciters with the Dayton Ultras???? Oh man that just would of been sweet. LOL If my sm100 exciters were to break then I would definetly replace them with one of the Dayton exciters but like the saying if it aint broke dont fix it so I am just leaving it as it is untill then. lol

I am not sure on the haaaaaa sound but since they are ominidirectional/open baffle type of speakers maybe that could add to that haaaaaa sound you are refering too as sounding very open/wide. When playing certain music tracks in stereo mode it sounds like I have all 5 speakers playing in full surround, sometimes I have to check to make sure I didnt accidently hit the 5 channel button LOL. When watching movies I prefer Definitive speakers for that full audio impact but the bertagni's sm100 still beat them when it comes to voices and imaging.

With some EQ I know without a doubt the bertagni's can sound even better so my next step is too add a EQ.

I also use a sub with my sm100s. I bought some sliders used to move furniture around a while back and didnt use them. What I did was remove the foam from the plastic and put the foam on my subs feet it seemed to help blend my sub better with the bertagni speakers making is sound a little tighter and cleaner. Its basically a cheap diy version of the auralex sub/bass trap concept.