DIY Flat Panel Speaker Love

[buke9]

Re: DIY Flat Panel Speaker Love

You can use your multimeter set to D.C., there should be no offset voltage present, except for a few millivolts.
Most amps have some sort of protection circuit to keep D.C from getting to the speakers.

Jack

OK just checked with multimeter and the side that killed them is giving me a reading of 2.8 mv and the same on the other side and after letting it go for 5 or 6 minutes with no load the voltage went down on the not killing side to .7 mv and increased to 6.8 mv on the killing side. It's a really cheap meter but something is different from the two sides. I guess the NAD is out for pushing the panels. I just had to spend 2 grand on AC repair for the home so no new gear in the near future. I guess I can use the Hafler feed from my computer thru my Teac UD-301 DAC using eq from Foobar to help out for now. I might have to buy me a cheap class d amp. I like the Thruster sound better than the Ultra's but that is what I got right now.

[captainjack115]

Re: DIY Flat Panel Speaker Love

OK just checked with multimeter and the side that killed them is giving me a reading of 2.8 mv and the same on the other side and after letting it go for 5 or 6 minutes with no load the voltage went down on the not killing side to .7 mv and increased to 6.8 mv on the killing side. It's a really cheap meter but something is different from the two sides. I guess the NAD is out for pushing the panels. I just had to spend 2 grand on AC repair for the home so no new gear in the near future. I guess I can use the Hafler feed from my computer thru my Teac UD-301 DAC using eq from Foobar to help out for now. I might have to buy me a cheap class d amp. I like the Thruster sound better than the Ultra's but that is what I got right now.

OK, not a D.C. offset problem!

If the channel sounded clean, I doubt that there is some sort of asymmetrical waveform problem either. Hard to say, you'd probably need to do some under load test with equipment far exceeding a common multimeter. Something could be breaking down within that channel on dynamic peaks. NAD does this thing with varying the voltage supply rails to the final output transistors, called power envelope circuitry. The rail voltage is varied by the actual audio signal, something may have gone wrong.

I use one of those little Lepai 2020+ amplifiers for casual testing on panels.

Hope this helps.

Jack

[buke9]

Re: DIY Flat Panel Speaker Love

OK, not a D.C. offset problem!

If the channel sounded clean, I doubt that there is some sort of asymmetrical waveform problem either. Hard to say, you'd probably need to do some under load test with equipment far exceeding a common multimeter. Something could be breaking down within that channel on dynamic peaks. NAD does this thing with varying the voltage supply rails to the final output transistors, called power envelope circuitry. The rail voltage is varied by the actual audio signal, something may have gone wrong.

I use one of those little Lepai 2020+ amplifiers for casual testing on panels.

Hope this helps.

Jack

Just weird it made no strange noise before it went . I was thinking of getting one of those Lepai's that I saw you mentioned before. Now on to fitting the Ultra's to the panels. Just looked at specs of an old AVR that I have back in the closet and found it is ok with 4 ohm speakers.

[captainjack115]

Re: DIY Flat Panel Speaker Love

I have not tried a spline mount want to try it myself at some point. I would want a soft complaint mounting between the exciter and spline to allow some movement. Something like a large dab of silicon or ???

That's exactly what I thought!

A dab of silicone would keep the exciter from vibrating the rest of the framework,there would also be some offset support to the back of the exciter.

Jack

[Fshow]

Re: DIY Flat Panel Speaker Love

That's exactly what I thought!

A dab of silicone would keep the exciter from vibrating the rest of the framework,there would also be some offset support to the back of the exciter.

Jack

Hi all

My panels are 24" x 60" x 1". I am using Thrusters ( one died after a few minutes, but the replacement has been working fine for months now). I fastened the exciter with silicon attached to a spline. The panel is glued directly to a frame. The frame and spline are 1 x 2's but but I doubled up the frame and spline to keep vibrations to minimum. I am very happy with the result,( i do have to equalize). I have tried various size panels without a frame and spline but the panels all rattled, (because I was running them full range). With the frame and spline the speakers operate full range without rattling. I heard no loss of detail by adding a frame and spline. The consensus out there seems to be that larger panels, hard fixed to a frame with a spline won't have the magic,,,,,I am not so sure this is true. I can see how smaller panels with a sub woofer would out preform a single panel, but there is something to be said for a full range speaker, and you will be amazed at how low these panels will go. One thing I should mention is that these speakers really began to shine when I connected it to a better Tamp running on a battery. The battery really made a big improvement.

It's all fun....thanks guys.
Fred

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hi all

My panels are 24" x 60" x 1". I am using Thrusters ( one died after a few minutes, but the replacement has been working fine for months now). I fastened the exciter with silicon attached to a spline. The panel is glued directly to a frame. The frame and spline are 1 x 2's but but I doubled up the frame and spline to keep vibrations to minimum. I am very happy with the result,( i do have to equalize). I have tried various size panels without a frame and spline but the panels all rattled, (because I was running them full range). With the frame and spline the speakers operate full range without rattling. I heard no loss of detail by adding a frame and spline. The consensus out there seems to be that larger panels, hard fixed to a frame with a spline won't have the magic,,,,,I am not so sure this is true. I can see how smaller panels with a sub woofer would out preform a single panel, but there is something to be said for a full range speaker, and you will be amazed at how low these panels will go. One thing I should mention is that these speakers really began to shine when I connected it to a better Tamp running on a battery. The battery really made a big improvement.

It's all fun....thanks guys.
Fred

Hey FShow... been wondering where you have been!? Okay, this is plain blasphemy... first the rigid suspension, which I could have over looked, but now the Thrusters as well!? Unacceptable!!

All kidding aside, surely there is no single "best" approach to making the panels sing. Everyone hears things differently and prefer certain aspects of a design over another... none are right or wrong and we only need to please your own ears! Its hard for me to believe that the guys prefer the Thrusters over the Ultra's on lightly suspended XPS panels; to my ears they are "quieter" (less panel noise) and have more clarity and detail. But that is why we user different exciters, panel materials and sizes. But I will say this; someday I will try the spine and rigid suspension mounting. Say Fred, I can't remember, but did you post a freq. response for your panels? Seems like these 2x6 were bigger than the previous panels yes? I'm curious what the rigid suspension does to the freq. response.

But to your point, a large panels does need more suspension than a smaller panel. I didn't have panel noise, so to speak, on my lightly suspended large panels (2x5) but on very loud booming male voices (e.g. Muddy Waters, Folk Singer), I got a drum resonance that was not properly damped by my normal light suspension so clearly something a bit extra needs to be done to prevent these types of resonances. And I will say also that overall, this is why I prefer smaller panels. I am in a minority on this aspect of panel design. But to my ears, the DML nodes leave the panel more quickly is seems. Sounds quicker and more dynamic but EQ is a must to create a more balanced response and slightly more extended bass (but high passed sharply below 40Hz).

I think really small panels have a use as well. I created a tiny panel 12" x 14.5" and found again more clarity and detail but more so they still filled the room and completely... and I mean COMPLETELY... disappeared in the room. If you didn't know that the small panels were speakers you really could not detect where the music was coming from. These don't operate as a line array so the presentation is different than listing to a 30"+ line array and you don't get that "headphone" effect that arrays present. I want to build a OB FAST system with a small panel to cover the 180-200Hz on up. They should sound very good and different from the full-range panels we listen to; even when combined with bass support from a sub or bass bin.

Agreed on the class D amps. I have a modded TPA3123 that I prefer over my Densen Beat ($1500 20+ years ago), Sumo, Sansui AU555 and other vintage amps I have about the house. Very clean, detailed yet not fatiguing in any way. Lacks the innner detail that my Quicksilver mono's had or even my old MFA equipment yet they are so very listenable. I'm heard very good things about battery power and also the Astron power supplies (some seem to prefer the Astron over the battery due to ability to deliver current quickly on peaks but maybe that is the magic that we hear in a battery power amp... softer, more rounded like a tube amp??)

Anyway... blah, blah, blah... gotta get back to work... :-)

Take care FShow and drop by more often man!

[Fshow]

Re: DIY Flat Panel Speaker Love

Hey FShow... been wondering where you been!? Okay, this is plain blasphemy... first the ridges suspension, which I could have over looked, but now the Thrusters as well!? Unacceptable!!

All kidding aside, surely there is no single "best" approach to making the panels sing. Everyone hears things differently and prefer certain aspects of a design over another... non are right or wrong and only need to please your own ears! Its hard for me to believe that the guys prefer the Thrusters over the Ultra's on lightly suspended XPS panels; to my ears they are "quieter" (less panel noise) and have more clarity and detail. But that is why we user different exciters, panel materials and sizes. But I will say this; someday I will try the spine and rigid suspension mounting. Say Fred, I can't remember, but did you post a freq. response for your panels? Seems like these 2x6 were bigger than the previous panels yes? I'm curious what the rigid suspension does to the freq. response.

But to your point, a large panels does so need more suspension kthan a smaller panel. I didn't have panel noise, so to speak, on my lightly suspended large panels (2x5) but on very loud booming male voices (e.g. Muddy Waters, Folk Singer), I got a drum resonance that was not properly damped by my normal light suspension so clearly something a bit extra needs to be done to prevent these types of resonances. And I will say also that overall, this is why I prefer smaller panels. I am in a minority on this aspect of panel design. But to my ears, the DML nodeus leave the panel more quickly is seems. Sounds quicker and and more dynamic to me and EQ is a must to create a more balanced response and slightly more extended bass (but high passed sharply below 40Hz).

I think really small panels have a use as well. I creatediii a tiny panel 12" x 14.5" and found again more clarity and detail but more so the still filled the room and completely... and I mean COMPLETELY disappeared in the room. If anyone who didn't know that the small panels were speakers you really could not detect where the music was coming from. These don't operate as a line array so the presentation is different than listing to a 30" line array and you don't get that "headphone" effect that arrays present. I want to build an OB FAST system with a small panel to cover the 180-200Hz on up. They should sound very good and different from the full-range panels with listen to; even when combined with bass support from a sub or bass bin.

Agreed on the class D amps. I have a modded TPA3123 that I prefer over my Densen Beat ($1500 20+ years ago), Sumo, Sansui AU555 and other vintage amps I have about the house. Very clean, detailed yet not fatiguing in any way. Lacks the innner detail that my Quicksilver mono's had or even my old MFA equipment yet they are so very listenable. I'm heard very good things about battery power and also the Astron power supplies (some seem to prefer the Astron over the battery due to ability to deliver current quickly on peaks but maybe that is the magic that we hear in a battery power amp... softer, more rounded like a tube amp??)

Anyway... blah, blah, blah... gotta get back to work... :-)

Take care FShow and drop by more often man!

Hi Rich

I sure do appreciate you and your comments!!! my panels are 2 x 5 and I did post some graphs. I have been hanging around but summers get busy. Sounds like you have a good plan in mind, fast is good. I am in no way discounting small panels, the lower mass should make for less distortion, but even these small panels would benefit from some edge damping.

The reason I am continuing down the single panel design, at least for now, is because it doesn't require a crossover or a bass driver, has a smaller footprint and the sound is so very integrated and fast.

I have been thinking of building a larger and thicker set of panels,,just to see what happens. Don't you wish you could just snap your fingers to try a different design or idea? Oh well.
Keep up the good work Rich.

P.S. I don't know if the thrusters are better than the Ultra's. I have never tried the Ultra's. The Thrusters have a very stiff suspension, I don't know if this is bad or good but I suspect it is good.

Fred

[rmeinke]

Re: DIY Flat Panel Speaker Love

There is a real draw for me to use a single panel as well... EQed and the bass is certainly above average. I'm just spoiled by my open baffles. I do have a feeling that a good number of others who have the room and like to rock may opt for a sub or 2 but to each his own.

I still prefer as light as suspension as possible with no panel self-noise. To my ears, even touching the sides of the panels with your fingers I hear some of the air go away. I still prefer as light as possible... so long as there is no panel noise. With your full-range, large panels something certainly needs to be done... that is true.

Funny you mention larger and thicker. Someone over at DIY Audio (me thinks) used a full sheet of 1.5 or 2" thick XPS for a DML "sub". VERY curious how that would go as well. Probably use a bass shaker for that. CLS who has built many panels and speakers in general (sweetest open baffle setup I have ever seen) said his bass shaker panels had the snappiest and most dynamic bass he has ever heard... drums were simple amazing.. this from a very seasoned and knowledgeable guy got my attention. Since reading and hearing these results I've wanted to build one.

Next PE order will have a bass shaker or 2 added. :-)

To your Thruster suspension comment. Through my listening sessions, the Thrusters sound better to me with heavier or thicker materials (ply) as the steel suspension can exert more pressure on the panel. The Ultras have excursion issues when trying to modulate a heavy panel, the soft suspension simply does not transfer as much energy to the panel. however the Ultra in my experience is easily the best on lighter materials like XPS... the very compliant, soft suspension floating motor design makes for a quieter panel. There is less panel noise with the Ultra and the detail and clarity is improved. I could tell this from the first few seconds of listening. As much as I liked the Thrusters, the Ultras bested them on my panels. I would tend to think the Thrusters would be better on your large, well damped panels.

Gotta run... later!!

[Fshow]

Re: DIY Flat Panel Speaker Love

There is a real draw for me to use a single panel as well... EQed and the bass is certainly above average. I'm just spoiled by my open baffles. I do have a feeling that a good number of others who have the room and like to rock may opt for a sub or 2 but to each his own.

I still prefer as light as suspension as possible with no panel self-noise. To my ears, even touching the sides of the panels with your fingers I hear some of the air go away. I still prefer as light as possible... so long as there is no panel noise. With your full-range, large panels something certainly needs to be done... that is true.
Kk
Funny you mention larger and thicker. Someone over at DIY Audio (me thinks) used a full sheet of 1.5 or 2" thick XPS for a DML "sub". VERY curious how that would go as well. Probably use a bass shaker for that. CLS who has built many panels and speakers in general (sweetest open baffle setup I have ever seen) said his bass shaker panels had the snappiest and most dynamic bass he has ever heard... drums were simple amazing.. this from a very seasoned and knowledgeable guy got my attention. Since reading and hearing these results I've wanted to build one.

Next PE order will have a bass shaker or 2 added. :-)

To your Thruster suspension comment. Through my listening sessions, the Thrusters sound better to me with heavier or thicker materials (ply) as the steel suspension can exert more pressure on the panel. The Ultras have excursion issues when trying to modulate a heavy panel, the soft suspension simply does not transfer as much energy to the panel. however the Ultra in my experience is easily the best on lighter materials like XPS... the very compliant, soft suspension floating motor design makes for a quieter panel. There is less panel noise with the Ultra and the detail and clarity is improved. I could tell this from the first few seconds of listening. As much as I liked the Thrusters, the Ultras bested them on my panels. I would tend to think the Thrusters would be better on your large, well damped panels.

Gotta run... later!!

Thanks Rich

That's a lot of good information. It surprises me that even touching the panels you loose something, but I believe you. You must have it crossed over just high enough to where the mass of the panel doesn't overshoot the exciter. So panel size, weight, stiffness, exciter, and crossover freq are all related. (Just guessing,,,for sure!!!!!)
If you ever run into that article on the full size 2 inch panels again please post the link.

Thanks again
Fred

[opadave]

Re: DIY Flat Panel Speaker Love

Hey buke, just a thought - you might have an rf feedback loop on that left side. It would odd but possible. I've had a couple bass (guitar) speakers killed by that. It was the amp and replacing the amp took care of the problem. It turns out that it was transmitting some rf frequency that ANY nearby wire picked up.
Don't know if it helps but....
opa

[rmeinke]

Re: DIY Flat Panel Speaker Love

Thanks Rich

That's a lot of good information. It surprises me that even touching the panels you loose something, but I believe you. You must have it crossed over just high enough to where the mass of the panel doesn't overshoot the exciter. So panel size, weight, stiffness, exciter, and crossover freq are all related. (Just guessing,,,for sure!!!!!)
If you ever run into that article on the full size 2 inch panels again please post the link.

Thanks again
Fred

Hey Fred, I think in this case its more of a matter of proportions. The amount of damping applied by hanging on to panels is greater on my smaller panels. A larger panel would take more hands to apply enough damping to impact panel output. But for me its a study of damping and what can happen as greater amounts of damping is applied to a panel. But to be realistic, hands will absorb uber amounts of energy compared to, say, a piece of felt used for suspending a panel... have to think hands apply heaviest damping.

Here is a interesting set of measurements:

http://www.diyaudio.com/forums/full-...e-speaker.html

The panels are really small but I did find it interesting that the distortion was lowest on the undamped panel. The OP used globs of modeling clay. Can't draw direct comparisons to the panels we are building but interesting... not only from a distortion perspective but also freq. response. The plain panel had the most extended FR.

A few more on larger panel "Subs":
http://www.diyaudio.com/forums/subwo...subwoofer.html
http://www.diyaudio.com/forums/plana...questions.html

There is more good info on the AC thread but that's hard to get to with all the info buried in the threads.

[captainjack115]

Re: DIY Flat Panel Speaker Love

Hi Guys

Only one or two things new on my end.

Sent back the ipod Touch, bought a Behringer DEQ2496 instead. I must say, the Auto-EQ function did amazing things for the small Coroplast panels I'm messing with. As most of you know, I'm not doing the full range approach with my project. So far my best effort results have been crossing over my 12X12" panels at 200hz. Last week my musically inclined Stepson had a listen to my panels sans Behringer, and he was practically ranting about what he heard. He'll be here again this afternoon, and I'll be showing him my latest toy, ala-Behringer.
Admittedly, a bit of a pain to have the microphone cord stretched out across the floor and having to use XLR cables and adapters, but worth the results.

Still using and preferring the Thrusters over the Ultras, the Coroplast panels are light, but still sound better with the Thrusters. In direct comparison, the Ultras have a hollow sound to my ears, although they don't look a whole lot different in measurement. Still weighing my options on suspension, dealing with the edge vibration is a tricky thing. I'd like to go back to using 4 stacked panels in an line array as before, but it's going to have to pass spouse approval this time.

One panel per channel would work for me but post EQing is going to eat into my power handling. I have been able to listen to a pair of panels up to 100db in my small room, but I'm not comfortable with the fear of impending exciter failure. Having 4 panels per side would give me a 6 db advantage.

Jack

[Fshow]

Re: DIY Flat Panel Speaker Love

Hey Fred, I think in this case its more of a matter of proportions. The amount of damping applied by hanging on to panels is greater on my smaller panels. A larger panel would take more hands to apply enough damping to impact panel output. But for me its a study of damping and what can happen as greater amounts of damping is applied to a panel. But to be realistic, hands will absorb uber amounts of energy compared to, say, a piece of felt used for suspending a panel... have to think hands apply heaviest damping. u

Here is a interesting set of measurements:

http://www.diyaudio.com/forums/full-...e-speaker.html

The panels are really small but I did find it interesting that the distortion was lowest on the undamped panel. The OP used globs of modeling clay. Can't draw direct comparisons to the panels we are building but interesting... not only from a distortion perspective but also freq. response. The plain panel had the most extended FR.

A few more on larger panel "Subs":
http://www.diyaudio.com/forums/subwo...subwoofer.html
http://www.diyaudio.com/forums/plana...questions.html

There is more good info on the AC thread but that's hard to get to with all the info buried in the threads.

Hi Rich

Sorry about the late reply, it's been crazy around here. You guys are persuading me to retry small panel, but what I might try is using a large panel for low freq and a smaller panel for the highs. I have a really good single panel full range to compare it to. I'm afraid It won't happen until winter though.

Thanks again

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hi Guys

Only one or two things new on my end.

Sent back the ipod Touch, bought a Behringer DEQ2496 instead. I must say, the Auto-EQ function did amazing things for the small Coroplast panels I'm messing with. As most of you know, I'm not doing the full range approach with my project. So far my best effort results have been crossing over my 12X12" panels at 200hz. Last week my musically inclined Stepson had a listen to my panels sans Behringer, and he was practically ranting about what he heard. He'll be here again this afternoon, and I'll be showing him my latest toy, ala-Behringer.
Admittedly, a bit of a pain to have the microphone cord stretched out across the floor and having to use XLR cables and adapters, but worth the results.

Still using and preferring the Thrusters over the Ultras, the Coroplast panels are light, but still sound better with the Thrusters. In direct comparison, the Ultras have a hollow sound to my ears, although they don't look a whole lot different in measurement. Still weighing my options on suspension, dealing with the edge vibration is a tricky thing. I'd like to go back to using 4 stacked panels in an line array as before, but it's going to have to pass spouse approval this time.

One panel per channel would work for me but post EQing is going to eat into my power handling. I have been able to listen to a pair of panels up to 100db in my small room, but I'm not comfortable with the fear of impending exciter failure. Having 4 panels per side would give me a 6 db advantage.

Jack

Hey Jack! Nice upgrade man... I really like my Behringer. Solves many design issues all in one package and can experiment with different aspects of the design so quickly. I liked the panels au naturel but once I EQed and listened to them for some time I could not go back. Just try turning off the EQ now and tell me you prefer the sound?

Spot on about the one exciter per channel... I prefer the option to EQ, extend the low freq. and cross at different points so appreciate the multiple panel approach yet maintaining the pure 1 exciter to 1 panel configuration. And while a single 12x12 panel is crystal clear and "fun" to listen too (esp. once EQed and extended down to 110Hz) and I could be more than perfectly happy with this combined with a sub there is still value (if you can integrate into the room well enough) in the thin and tall panel array (4 panels like what you have). Listening within the focused array is like walking *into* the venue... anyone who has listened to a well done line array will know what I'm talking about.

But like I said... that is IF you can integrate the array into your room. My dedicated listening room is pretty small and think that if I *had* to pick a single panel it might be a small panel and open baffle bass bin combo. In my listening room I would probably go with a larger line array.

To the Ultras and Thrusters, I had the same hollow or maybe "distant" sound quality with the Ultra's on think ply and preferred the Thrusters on ply. They are not as good on heavier or probably even with tightly/well damped suspension. So I would venture and guess that the Coroplast is light in general terms but compared to XPS they are may be a few times heavier... wish I had a small, accurate scale to have the actual weights so we could begin to dimension when the preference goes from Ultra to Thruster. I've only listened to Ultra's on panels 24"x30" panels or smaller (down to 12 x 14.5" roughly) so can not really gauge this well yet.

Since you have the Ultra's you should build a XPS panel!

OHHHhhhhh, and did anyone see the new Dayton Audio DAEX32Q-8 Dual Steel Spring Balanced 32mm Exciter 40W 8 Ohm exciters??? Could be a perfect solution to a 2 panel array. More sensitive once wired in parallel... hope they sound as good as the Thrusters... would be an excellent addition and option for arrays!

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hi Rich

Sorry about the late reply, it's been crazy around here. You guys are persuading me to retry small panel, but what I might try is using a large panel for low freq and a smaller panel for the highs. I have a really good single panel full range to compare it to. I'm afraid It won't happen until winter though.

Thanks again

Yo Fred!! This would be interesting to use a combo of small and large panels. In addition to the new 8ohm exciters above, I am really itching to try a VERY large 4x8 sheet of 1.5 or 2" XPS with 2 bass shakers driven my 2 - 300 watt Yung plate amps I have around. 1 panel and 2 shakers so only pseudo stereo but not much stereo below 100Hz so should not be an issue. That panel should REALLY go low. Just want to listen to such a panel... bet it would be snappy as hell like the smaller DML panels... just hearing what some others have commented on the basic quality... and that was a combination of shaker/exciter to create a single full-range panel. Too many design obstacles for that to happen but a single BASS panel should be more simple.

Your rigid frame might work good for that specific design...