DIY Flat Panel Speaker Love

[rmeinke]

Re: DIY Flat Panel Speaker Love

I've read all of that thread, and keep an eye on it. I've seen people propose this sort of thing, and in particular the impressive driver you mention, but I've not seen any significant follow through.

Btw that Tang band driver has no spider...

I don't think a large Xmax is required for this, I'd be looking for linearity and the ability to operate consistently over a wide frequency range.

I think the exciters we're using are intended for mid-fi. The fact that good (but not excellent) results are reported is encouraging. If you search billionsound in China you'll find these exciters in their OEM form. I think they are being rebadged Dayton. In quantity they are just a few dollars each.

okay... not sure if your coming or going. Agreeing or disagreeing on this one Gary.

All I am saying on this specific discussion is that the small TB subs would, if done to the best of your ability, operate in a similar way as Frank's custom exciter for all intents and purposes.

Obviously we want a stiffer suspension but Franks solution and the TB would work in a very similar way as the custom exciter used 2 fairly standard spiders to center the VC in the gap. I don't know about the specifics about the different TB micro subs but there has to be a spider of some type to keep the VC aligned and centered in the gap. If not a conventional spider, some mechanism to perform the same duty... I have a hard time believing that the surround would be able to keep the VC aligned yes?!?

You are correct about the Dayton's... it does indeed look like they re-badge these and from Viston and possibly others. Welcome to the global economy eh?!? :-)

In general, I do not know of a high-end exciter at this time?!? But if you do... lets us know.

Both Podium and Tectonic have used exciters very similar to what we are using and sourced originally from HiWave I believe(yes... then purchases by FLAT Audio, blah, blah, blah). I am sure that there have been changes, but the exciters are very nearly the same. If you look over the old AC threads you will find the exact exciter model used in the Podiums some years back and there was an equiv. sold at PE. Actually... they are very similar to the TEAX25C10-8/SP exciter that PE still carries now. PE used to carry more of the HiWave exciters but the higher-power models have not been restocked. One of the models mentioned in the AC thread sold out at PE not that many months ago actually... had some in my basket but were gone before I finally decided to pull the trigger. I have 4 of the TEAX25C10-8/SP exciters... hoping that they may be more reliable and sound good.

I can't say which of the Podium reviews it was (6 moons maybe ??), but Shelley Katz himself showed up at the reviewers door to replace an exciter on one of the panels. Always seemed to me that exciters by their very nature are not very reliable... including those used on speakers approaching the $10,000 range.

But I can agree with you on this... it would be nice to have a more reliable exciter that also happens to sound good.

[Gary.M]

Re: DIY Flat Panel Speaker Love

Just for interest, the Podium speakers manufacture and marketing was moved to France a few years back, and the website is here:

http://www.podium-sound.com/

I'm not sure whether Shelly Katz is still involved. However the guy who is running this is a friend, and business colleague. He has extolled the virtues of the technology to me for a while.

Next time I'm talking to him I'll ask if I can have a look at one of the Podium drivers..

[rmeinke]

Re: DIY Flat Panel Speaker Love

Just for interest, the Podium speakers manufacture and marketing was moved to France a few years back, and the website is here:

http://www.podium-sound.com/

I'm not sure whether Shelly Katz is still involved. However the guy who is running this is a friend, and business colleague. He has extolled the virtues of the technology to me for a while.

Next time I'm talking to him I'll ask if I can have a look at one of the Podium drivers..

Yeah...I wondered about Podium... the website updates stopped in 2010. I wish your friend best wishes and hope he can make a good run at the commercial market with those panels!

[Gary.M]

Re: DIY Flat Panel Speaker Love

Yeah...I wondered about Podium... the website updates stopped in 2010. I wish your friend best wishes and hope he can make a good run at the commercial market with those panels!

Oh he's been involved since about 2007. I think the project is in hiatus since about 2011/12. The EU consumer economies are not in a great state since the Global Financial Crisis.

[rmeinke]

Re: DIY Flat Panel Speaker Love

one more thing...

One concept to kick around... what does everyone think about settling on a easy to build, simple, common "reference" panel and exciter so that we can begin to compare different designs?

We seem to go sideways more often than we go forward and we can not honestly say whether *this* design sounds better than *that* design, etc., etc.

Of course personal preference vary and there will be disagreement is what "sounds best" to each of us but have to think that we would at least get closer and help to continue to improve the sound quality of our flat panels.

Thoughts?

Ok... just ONE MORE TIME... any feedback on this? This might be the best way to really determine progress and differences between the multitudes of panel designs and exciters we are using?!?

Thoughts??

[Gary.M]

Re: DIY Flat Panel Speaker Love

Ok... just ONE MORE TIME... any feedback on this? This might be the best way to really determine progress and differences between the multitudes of panel designs and exciters we are using?!?

Thoughts??

It's a good idea, but I'm not sure this thread is active enough to deliver that sort of collaboration. Access to the same panel materials is a problem with people in different countries.

Perhaps at least a couple of people with access to the same materials could be a start?

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hello Gary! Yeah, I am active over at AudioCircles in the mother thread as well so we have quite good coverage for these flat panels.

Good point about the panel material. XPS/EPS should have good availability but maybe add a 1/16" or 1/8" (and equiv metric panel thickness 3/5mm?) birch panel as a standard?

Think that should provide good coverage. But I do want to go back and try the treated cardboard panels. After curing for over a year and a half the shellac treated panels have really stiffened up. Even doubled up, they *might* be lighter and more rigid than ply. Also like to treat with PVA:water (with more PVA) as it should make it easier to treat the panels but this assumes the treatment will soak into the flutes. Treating each with shellac was a real pain and didn't bother any more with them due to the amount of work to treat the panels... no fun!

As for exciters, probably the Ultra on XPS and Thruster or DAEX30HESF-4 on ply would give the best performance.

Panel size 24" x 32.5" panel size would be a good compromise on size and performance. I recently disconnected the little Dayton sub and EQed my 24" x 30" panels and sounded as extended but not the same quality as the sealed Dayton. Low freq. performance of DML panels has never been an aspect that I think well of. My OB bass bins perform fantastically with the panels but the little sealed Dayton also works very well for music if your output levels are modest like mine. Really enjoy these panels with LF support provided by a sub.

Anyway... thanks for the input and look forward to others ideas. Once we get a solid approach and have some agreement I'll post over at AC.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hello there Kornbread! Think you are still in some uncharted waters here with this large of panel and with solid mounting in the corners but understanding more where you are now. In hindsight, if I were you I would have placed the tabs more like in my drawing of the suggested soft suspension and some of the harshness is likely coming from the hard, straight edges and corners not terminated in some “kind” way... however it is the hard mounting at the corners with no support of the panel across the longest dimension (even the shortest would need help) is causing the most issues here I'm afraid. Most of it due to the large panels.

I have NOT enjoyed large panels either Kornbread and for many of the same qualities you have listed in your post. My panels were 24" x 48" so yours are bigger still. My feelings are that while you could improve the performance it would not be enough. Over on the mother thread, I asked the large panel guys what can be done to get rid of the drum resonance and I got no solid responses back. Also, the quality of the lower bass is not on par with the rest of the panel; even with smaller, better performing panels. Your observation of Johnny Cash was the same as mine with Muddy Waters on Folk Singer. Low, booming male voice really excited the drum resonance. It was this experience that has led me to small panels.

And you are absolutely right about EQ; no amount of it will get rid of the drummy, cupped hands, nasally with an echo quality that you are hearing with these big panels. The nodes are not able to leave the panel as quickly as they can with a smaller panels.
If you still want a full-range DML, a multi-panel array using small panels would be the best. There are still some qualities that need to be adjusted too, but given your last post (and the fact that you come from a OB and panel speaker background) you will not enjoy anything but smaller panels. Whether you EQ and listen to them full range or cross to a sub or OB H/U/? frame would be up to you and what you want to accomplish with your audio system.

Do you care what the panels look like for the first iteration and the testing that you are doing? I’d half your panels and look for a simple, free mounted implementation with 2 panels per side. Still large panels but will move you in the right direction. You might also want to consider making the panels smaller if you want to use a sub or your OB panels for bass duties.

Curious where you want to take these. I might travel along with you on this one…

And just to be clear... comments above are in regard to performance with XPS/EPS. Other materials bring another set of design and performance characteristics. Need to mention this in case you want to change panel materials. :(

[Kornbread]

Re: DIY Flat Panel Speaker Love

Hello there Kornbread! Think you are still in some uncharted waters here with this large of panel and with solid mounting in the corners but understanding more where you are now. In hindsight, if I were you I would have placed the tabs more like in my drawing of the suggested soft suspension and some of the harshness is likely coming from the hard, straight edges and corners not terminated in some “kind” way... however it is the hard mounting at the corners with no support of the panel across the longest dimension (even the shortest would need help) is causing the most issues here I'm afraid. Most of it due to the large panels.

I have NOT enjoyed large panels either Kornbread and for many of the same qualities you have listed in your post. My panels were 24" x 48" so yours are bigger still. My feelings are that while you could improve the performance it would not be enough. Over on the mother thread, I asked the large panel guys what can be done to get rid of the drum resonance and I got no solid responses back. Also, the quality of the lower bass is not on par with the rest of the panel; even with smaller, better performing panels. Your observation of Johnny Cash was the same as mine with Muddy Waters on Folk Singer. Low, booming male voice really excited the drum resonance. It was this experience that has led me to small panels.

And you are absolutely right about EQ; no amount of it will get rid of the drummy, cupped hands, nasally with an echo quality that you are hearing with these big panels. The nodes are not able to leave the panel as quickly as they can with a smaller panels.
If you still want a full-range DML, a multi-panel array using small panels would be the best. There are still some qualities that need to be adjusted too, but given your last post (and the fact that you come from a OB and panel speaker background) you will not enjoy anything but smaller panels. Whether you EQ and listen to them full range or cross to a sub or OB H/U/? frame would be up to you and what you want to accomplish with your audio system.

Do you care what the panels look like for the first iteration and the testing that you are doing? I’d half your panels and look for a simple, free mounted implementation with 2 panels per side. Still large panels but will move you in the right direction. You might also want to consider making the panels smaller if you want to use a sub or your OB panels for bass duties.

Curious where you want to take these. I might travel along with you on this one…

And just to be clear... comments above are in regard to performance with XPS/EPS. Other materials bring another set of design and performance characteristics. Need to mention this in case you want to change panel materials. :(

Wasn't sure about leaving the tabs in the corners as a link Gary posted showed them to be the most active parts of the panel. Either way, it is done. Overall, it seems to be an improvement over solid mounting.

IIRC, you have posted about noticing some impressions of a nasal, cupped quality even with smaller panels. That leads me to believe there is something inherently wrong which may not be strictly related to the physical size of the panel. Either panel material or it's just the nature of the beast.

ps..... There are relatively few measurements found in this or the AC thread, good information for sure, not much in the way of evidence though. This is being done as a learning experience with the aid of measurements which will not only help me but others that may be heading this direction. What I hear is strictly what I hear and may be nothing like what you or anyone else hears ... it is subjective. I'm not going to go on a rant proclaiming the next mod or panel material the golden cow, I'll give you my honest opinion and lay the measurements out there for the rest of you to interpret the way you see fit.

YMMV

[Kornbread]

Re: DIY Flat Panel Speaker Love

Next step; mount a brace across the frame to support the exciter. The exciter is in a neutral position, neither pushing forward or pulling backward, and is held in place with liberal amounts of hot glue.


On to the measurements:

With tabs holding corners and no brace=Red, with tabs holding corners and the exciter held with brace=purple. Listening says bass is cleaner and fuller with exciter braced. Something noticed while listening to the braced version vs non braced, there seems to be more detail in the mid and upper range. Maybe this is due to the trough around 1k and 4-5.5kz being better filled?




With tabs holding corners and brace=Purple, solid mounted panel=Green, tabs holding corner and no exciter brace=Red
The treble has gained output solid mount vs tabs and overall the frequency response became smoother as 1) the panel was free'd from the frame, 2) and the exciter was mounted to a support. Also notice the treble response, other than the large suckouts around 9 and 12kz there is response out to 20kz in level with the midrange. Poor treble extension was often mentioned in the AC thread, not the case here.


The waterfall plot and spectrogram look smoother with the tabs holding the corners and exciter braced vs solid mount or tabs in corners and no exciter brace.




Dug these measurements up of the Carver AL's. Carvers at listening distance ~ 12' with them placed about 4' out from wall in a 16'x20' room with odd shaped ceiling w/IB subs=Yellow, flat panels w/exciter brace and corner tabs at 1 meter=Green

[rmeinke]

Re: DIY Flat Panel Speaker Love

Yeah, past the decision but just wanted to comment on the result.

The cupped hands and nasally quality is with the new DAEX32Q-4 4 Ohm excited. When I went back to the Ultra I swear I made an audible Aaaaaaaaahhh sound. Thrusters on 16" ply was also much better. I don't want to count out this exciter just yet as I only tested on XPS. This thing is built like a tank and seems like it ought to be reliable so will be trying it on ply fairly soon.

[Kornbread]

Re: DIY Flat Panel Speaker Love

Then I should mention, all of these measurements and impressions were using one DAEX32EP-4 per xps panel. I do question how reliable they are as one already STB.

Please list what other exciters you have experience with and your take on them.

Have another panel curing ...

[Gary.M]

Re: DIY Flat Panel Speaker Love

Kornbread, with the post I linked I think the information to take is that the best places to mount are those with minimum energy, so definitely not the corners. Also nxt and Podium and others experience on the forums shows advantage in rounding the corners.

Very interested in your postings and measurements as you are leading the way ahead of my experimentation.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Next step; mount a brace across the frame to support the exciter. The exciter is in a neutral position, neither pushing forward or pulling backward, and is held in place with liberal amounts of hot glue.


On to the measurements:

With tabs holding corners and no brace=Red, with tabs holding corners and the exciter held with brace=purple. Listening says bass is cleaner and fuller with exciter braced. Something noticed while listening to the braced version vs non braced, there seems to be more detail in the mid and upper range. Maybe this is due to the trough around 1k and 4-5.5kz being better filled?


[ATTACH=CONFIG]61899[/ATTACH]

With tabs holding corners and brace=Purple, solid mounted panel=Green, tabs holding corner and no exciter brace=Red
The treble has gained output solid mount vs tabs and overall the frequency response became smoother as 1) the panel was free'd from the frame, 2) and the exciter was mounted to a support. Also notice the treble response, other than the large suckouts around 9 and 12kz there is response out to 20kz in level with the midrange. Poor treble extension was often mentioned in the AC thread, not the case here.
[ATTACH=CONFIG]61899[/ATTACH]

The waterfall plot and spectrogram look smoother with the tabs holding the corners and exciter braced vs solid mount or tabs in corners and no exciter brace.
[ATTACH=CONFIG]61900[/ATTACH]
[ATTACH=CONFIG]61901[/ATTACH]


Dug these measurements up of the Carver AL's. Carvers at listening distance ~ 12' with them placed about 4' out from wall in a 16'x20' room with odd shaped ceiling w/IB subs=Yellow, flat panels w/exciter brace and corner tabs at 1 meter=Green
[ATTACH=CONFIG]61902[/ATTACH]

Hey Kornbread, this is really encouraging about spline mounting. There was a bit of a constant, underlying vibrational signature that was somewhat annoying when I went from the KEF Q500s back to the panels. Really hope that spline mounting might reduce this aspect of the panels.

I'm keeping my optimism in check somewhat here until we do more validating. With your large panels and only little tabs in the corners, the panels are really able to move freely so the spine mounting, I'm sure, brought a little stability to the panel and exciter. The tabs, I can only assume, make for *really* light suspension and cause the panels to possibly move *too* freely and responsible for the drummy, nasally, echo character that I also heard on my large panels. Appears that if you want to build large panels with light suspension, spline mounting may be the way to go. But you know what I'm going to ask next... how do they sound ? ?

My Omnimic has a large spike at 60Hz so I've not been able to test essentially since I got it. But did treat myself to an early Xmas present and got a MiniDSP 2x4 and matching UMIK-1 so will be joining in with REW measurements as well.

That is some elevated low freq. with the Amazing's... doubt they sound the way they measure. I never got what I felt was accurate OB bass measurements and always tweaked levels by ear with my Martin King based OB panels.

[Fshow]

Re: DIY Flat Panel Speaker Love

Hi all

For what it is worth, one of my earlier panels made of poster board and 4 cheap exciters in monocur arrangement sounded nasel. It was due to a peak in response around 1 kHz. I built a notch filter which mostly fixed the problem.
Currently with the Thruster and 1 inch xps the tone is ok. One thing I notice is your panel has a more linear responce where I need to equalize, this may be because my panel is more of a rectangle and yours is closer to square.

Fred