DIY Flat Panel Speaker Love

[Shadetreehifi]

Just a single data point here: I tried glue doped pink panther and eighth inch birch luan doped with minwax wood hardener. Panels are 2x6 feet. The luan panels sound great to my ears. The tonal balance is very similar to my acoustic research ar4x speakers, but with great transients and speed. The low end is augmented by a pair of ar1 woofers crossed at 120. The huge dispersion is a game changer for me. No more agonizing over the perfect stereo image sweet spot like with my Maggies. The high end seems to extend roughly to 16k or so, but then so does my hearing... My theory is that the balsa-like core of the luan, once stiffened by the minwax is a good medium for the mid and highs. The midrange is more natural to my ears than the Maggies. Great fun experimenting with these. This luan is the zero formaldehyde variety if that matters...

[Shadetreehifi]

As to the pink panther: louder for a given input and great transients, but I could never quite get over a slight background ringing in the human vocal range. Kind of like standing in a shower stall. The pink panther was three quarter thickness.
Also I'm running these exciters with plenty of headroom. 225 watts per channel rms. The exciters are the Dayton thrusters.

[Unbiasedsound]

Just a single data point here: I tried glue doped pink panther and eighth inch birch luan doped with minwax wood hardener. Panels are 2x6 feet. The luan panels sound great to my ears. The tonal balance is very similar to my acoustic research ar4x speakers, but with great transients and speed. The low end is augmented by a pair of ar1 woofers crossed at 120. The huge dispersion is a game changer for me. No more agonizing over the perfect stereo image sweet spot like with my Maggies. The high end seems to extend roughly to 16k or so, but then so does my hearing... My theory is that the balsa-like core of the luan, once stiffened by the minwax is a good medium for the mid and highs. The midrange is more natural to my ears than the Maggies. Great fun experimenting with these. This luan is the zero formaldehyde variety if that matters...

Good info, I might just try the birch luan doped with miniwax hardener.....Question, do you think the miniwax wood hardener can be applied to XPS or EPS without any corrosive effects?

[Unbiasedsound]

As to the pink panther: louder for a given input and great transients, but I could never quite get over a slight background ringing in the human vocal range. Kind of like standing in a shower stall. The pink panther was three quarter thickness.
Also I'm running these exciters with plenty of headroom. 225 watts per channel rms. The exciters are the Dayton thrusters.

225 watts rms???? I didnt think a 40watt rms exciter could handle that much power, unless you are utilizing more then one exciter?

[Kornbread]

As to the pink panther: louder for a given input and great transients, but I could never quite get over a slight background ringing in the human vocal range. Kind of like standing in a shower stall. The pink panther was three quarter thickness.
Also I'm running these exciters with plenty of headroom. 225 watts per channel rms. The exciters are the Dayton thrusters.

IMO, wood products, in general, seem to produce a more natural sound.

I too found the ringing of the dense foam board bothering. It led to experiments with cardboard saturated with minwax lacquer <(think it was lacquer). That exciter also died, wasn't even able to get a decent set of measurements, let alone any listening. Out of frustration with short-lived exciters, I gave up on the project ... at least for a while.

unbiasedsound, try it on a scrap piece first. If time allows tomorrow I'll try it and let you know.

[Gary.M]

Following are some comprehensive tests of two materials with several exciters. Note the vertical axis is in 5dB steps, and the smoothing is 1/6th octave. This may look bumpier than you are used to, but it is a more accurate picture. All graphs from pink noise measured in REW with Calibrated UMIK-1 from Cross Spectrum Labs.

[Gary.M]

First double layer corrugated cardboard. This is limited in high frequency extension with all exciters tried.

[Gary.M]

Next 3mm bamboo ply. This has very good high frequency extension. The Dayton Ultra exciter was a surprise... poor at high frequencies. You can click on the images to get a full sized picture.

[Gary.M]

The Tectonics exciter looked very good, so I tried it at a greater distance.

[Gary.M]

And if I use 10dB steps on the vertical axis (which I think is what we've been seeing in other posts on here)

[Gary.M]

In summary, I've been aiming for a panel that can go from about 200-300Hz on up, with an open baffle woofer filling in below. I may have what I want. Certainly a listen to this single bamboo panel was very impressive.

[Shadetreehifi]

225 watts rms???? I didnt think a 40watt rms exciter could handle that much power, unless you are utilizing more then one exciter?

Not a problem, as long as one uses the volume knob within reason. I've never had them heat up, even at room-saturating levels. I'm using one exciter per panel.

[rmeinke]

Just a single data point here: I tried glue doped pink panther and eighth inch birch luan doped with minwax wood hardener. Panels are 2x6 feet. The luan panels sound great to my ears. The tonal balance is very similar to my acoustic research ar4x speakers, but with great transients and speed. The low end is augmented by a pair of ar1 woofers crossed at 120. The huge dispersion is a game changer for me. No more agonizing over the perfect stereo image sweet spot like with my Maggies. The high end seems to extend roughly to 16k or so, but then so does my hearing... My theory is that the balsa-like core of the luan, once stiffened by the minwax is a good medium for the mid and highs. The midrange is more natural to my ears than the Maggies. Great fun experimenting with these. This luan is the zero formaldehyde variety if that matters...

Hello Sahdetreehifi!

+1 on the Laun ply. I do like the sound of my old Baltic Birch panels but they are over damped in my opinion. However Luan, being lighter and more resilient offers a more lively sound and natural sound... not unfamiliar to how XPS is more damped compared to the lighter and more resilient EPS.

Just curious, how are you suspending your panels? 2x6 is a large panel! :-)

[rmeinke]

As to the pink panther: louder for a given input and great transients, but I could never quite get over a slight background ringing in the human vocal range. Kind of like standing in a shower stall. The pink panther was three quarter thickness.
Also I'm running these exciters with plenty of headroom. 225 watts per channel rms. The exciters are the Dayton thrusters.

XPS can be made to sound good as well. Sounds like you may need more damping. I've preferred the Ultra on XPS as the more compliant suspension removes the background panel noise. Suspension plays a part as well naturally. Should have asked in my last post... how many exciters per panel??? I assumed a single exciter... but...

[rmeinke]

Next 3mm bamboo ply. This has very good high frequency extension. The Dayton Ultra exciter was a surprise... poor at high frequencies. You can click on the images to get a full sized picture.

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Hey Gary! Good to be back and see everyone posting!

The Ultra with its larger vc doesn't produce the most extended response... and it doesn't sound good on ply/heavier materials either. Its softer, more compliant suspension just can not exert enough force on heavier panels. I plucked them off my birch ply panels after less than an hour. Better suited to XPS/EPS panels.

I'm playing catch up here after being away for weeks, so apologies if its been stated, but what panel size, suspension/mounting? Sedge over at AC has reported good results with rigid mounting for ply. Should boost SPL and the low freq. response. A quick pine frame should provide some quick results.

Hope everyone is doing well!