DIY Flat Panel Speaker Love

[Jim Griffin]

Re: DIY Flat Panel Speaker Love

Now if these panels behaved like piston drivers, there is no hope of having much bass. First, for a piston driver its output will fall off by 12 dB per octave below its Fs. So if the system behaves like a piston, below 224 Hz (the Fs spec for this transducer), your amplitude would be down 12 dB at 112 Hz and then down 24 dB at 56 Hz. Second, for a dipole radiator its output is a function of its width and will fall off by 6 dB per octave as you go down in frequency. For a 2' wide panel you looking at an 18 dB per octave or greater decline below 224 Hz. Thus don't expect a lot of low frequency output.

It would help if we had frequency response data to assess how these panels perform. I'm interested in learning more about how they work.

[Jay1]

Re: DIY Flat Panel Speaker Love

Can you elaborate???

Hi Rich
After your suggestions in my OB Hestia build, I would give a try to the panels when I finished my Hestia.
Thanks.

Lets just say back when I was a young budding hifi noob that was the forum I found, and subsequently followed the advice of the "experts" over there. The a$$ wiping and flushing of several thousand dollars down the toilet was a lesson well learned about the audiophool world. It did push me to learn way more about audio then I might ever have, being the simpleton paint slinging aircraft maintainer that I am.

[rmeinke]

Re: DIY Flat Panel Speaker Love

I don't know if you can use conventional piston driver theory on these transducers but if it applies then let me state a couple of factors. First, for a piston driver its output will fall off by 12 dB per octave below its Fs. So if this system behaves like a piston, then below 224 Hz (the Fs spec for this transducer), your amplitude would be down 12 dB at 112 Hz and then down 24 dB at 56 Hz. Second, for a dipole radiator its output is a function of its width and will fall off by 6 dB per octave as you go down in frequency. For a 2' wide panel you looking at an 18 dB per octave or greater decline below 224 Hz. Thus don't expect a lot of low frequency output.

It would help if we had frequency response data to assess how these panels perform.

Hey Jim,
Yes, DML does operate on different principles. You can read a good introduction to Distributed Mode Loudspeaker technology here :

http://www.tectonicaudiolabs.com/wp-...rt-Version.pdf

Best regards,
Rich

[---k---]

Re: DIY Flat Panel Speaker Love

Looks like a fun little project. If I had time, I might give it a shot. Hopefully in 6 - 12 months I'll remember this. I would love to see photos of your project.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Looks like a fun little project. If I had time, I might give it a shot. Hopefully in 6 - 12 months I'll remember this. I would love to see photos of your project.

This are just test panels so absolutely nothing to look at now. However once the panels are framed up I will surely upload pics!

[rmeinke]

Re: DIY Flat Panel Speaker Love

Here are a few more links on DML panels and speaker reviews on the Podium Sound panels as well as their website.

http://www.phy.davidson.edu/FacHome/...Tflatpanel.htm

http://www.podium-sound.com/index-A.html?menu=70836

http://www.6moons.com/audioreviews/podium/1_2.html

http://www.stereomojo.com/Podium%20....akerReview.htm

Cheers!
Rich

[rmeinke]

Re: DIY Flat Panel Speaker Love

I'd be curious to see distortion measurements.

Hey Chaz,
Meant to post this yesterday. There are distortion plots in the link at the bottom.

Most panel speakers are not known for there low distortion (esp. low frequencies) but these apparently fair pretty well. Not outstanding by any means but reasonable.

Listening to these panels are interesting and tell the real story. If you can get past the diffused sound (omnidirectionality) and a soundstage that is presented further back in the listening plane, the sound is quite good if not amazing at times. Because the panel surface is large, excursions are small and the panels sound "fast"... percussion and plucked strings are fantastic and instruments have a very natural tone if the panel material is good and treated properly. Dynamic shading is the best I've heard to date... able to resolve fine details. Just fun to listen too... have not gone to bed before 1:00 AM this week as I just can't turn off the music...

http://www.phy.davidson.edu/FacHome/...l.htm#Heading3

[Pete Schumacher]

Re: DIY Flat Panel Speaker Love

Hey Chaz,
Meant to post this yesterday. There are distortion plots in the link at the bottom.

Most panel speakers are not known for there low distortion (esp. low frequencies) but these apparently fair pretty well. Not outstanding by any means but reasonable.

Listening to these panels are interesting and tell the real story. If you can get past the diffused sound (omnidirectionality) and a soundstage that is presented further back in the listening plane, the sound is quite good if not amazing at times. Because the panel surface is large, excursions are small and the panels sound "fast"... percussion and plucked strings are fantastic and instruments have a very natural tone if the panel material is good and treated properly. Dynamic shading is the best I've heard to date... able to resolve fine details. Just fun to listen too... have not gone to bed before 1:00 AM this week as I just can't turn off the music...

http://www.phy.davidson.edu/FacHome/...l.htm#Heading3

Respectable as you say. Nothing to really fault at all from that data.



And this would probably explain the recessed sound stage. Just a bit of EQ to bring up the range between 500 and 3000 would likely bring the stage up to the speakers where it belongs. Far better behaved than I would have guessed just giving them a cursory look.

[Chaz_H]

Re: DIY Flat Panel Speaker Love

it sounds very intriguing indeed. I wonder how distortion changes with the material used, or with the number of transducers. What about a speaker like this, where different panels are optimized for bass or treble production?

[donradick]

Re: DIY Flat Panel Speaker Love

Hey Chaz,
Meant to post this yesterday. There are distortion plots in the link at the bottom.

Most panel speakers are not known for there low distortion (esp. low frequencies) but these apparently fair pretty well. Not outstanding by any means but reasonable.

Listening to these panels are interesting and tell the real story. If you can get past the diffused sound (omnidirectionality) and a soundstage that is presented further back in the listening plane, the sound is quite good if not amazing at times. Because the panel surface is large, excursions are small and the panels sound "fast"... percussion and plucked strings are fantastic and instruments have a very natural tone if the panel material is good and treated properly. Dynamic shading is the best I've heard to date... able to resolve fine details. Just fun to listen too... have not gone to bed before 1:00 AM this week as I just can't turn off the music...

http://www.phy.davidson.edu/FacHome/...l.htm#Heading3

Thanks for the post! I may have some of the exciters, and HD is right around the corner.

[rmeinke]

Re: DIY Flat Panel Speaker Love

it sounds very intriguing indeed. I wonder how distortion changes with the material used, or with the number of transducers. What about a speaker like this, where different panels are optimized for bass or treble production?

[ATTACH=CONFIG]53297[/ATTACH]

Yo Chaz, the link doesn't work and curious what these panels are. Assume they are the Tectonic Plates pro panels. If so, I've heard very good things about them and one of the reasons why I decided to try the panels in the first place. Someone uttered the words "audiophile" speakers so I was intrigued. And with the design choice of the Heil AMT tweeter in the panel I was inclined to believe the high praise.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Respectable as you say. Nothing to really fault at all from that data.



And this would probably explain the recessed sound stage. Just a bit of EQ to bring up the range between 500 and 3000 would likely bring the stage up to the speakers where it belongs. Far better behaved than I would have guessed just giving them a cursory look.

Hey Pete,
Yeah, it is really hard to believe that an exciter stuck to a panel performs as well as it does. Crazy.

My panels do not measure like that as the panel material is different and who knows the number of exciters/positioning on the panels, etc. for the DML's measured above. I did EQ mine as flat as possible originally but the lack of presence and the feeling that the soundstage was distant didn't improve a great deal... so work continues.

Thanks for stopping by Pete!

[rmeinke]

Re: DIY Flat Panel Speaker Love

Thanks for the post! I may have some of the exciters, and HD is right around the corner.

Heck yeah Don... about $14 for a 4' x 8' 3/4 sheet of XPS and some wood glue and water and your set! HD will even cut the panels. I'd start with 2' x 4' panels. And don't forget to sand the sheen off the panels!

Later!

[Chaz_H]

Re: DIY Flat Panel Speaker Love

Yo Chaz, the link doesn't work and curious what these panels are. Assume they are the Tectonic Plates pro panels. If so, I've heard very good things about them and one of the reasons why I decided to try the panels in the first place. Someone uttered the words "audiophile" speakers so I was intrigued. And with the design choice of the Heil AMT tweeter in the panel I was inclined to believe the high praise.

was having trouble with the forum earlier, let's try again:

[Chaz_H]

Re: DIY Flat Panel Speaker Love

My guess is that these panels might be too small for bass reproduction, but then again, if a heavier material is used intentionally and relieved of treble content (with a crossover if necessary) it might work.