DIY Flat Panel Speaker Love

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

There is a lot to consider and try.

Sedge over at AC thins the front of the exciter to improve the HF output. But I picked up a 1-3/8" Dia Top Bearing Dish, Bowl & Tray Router Bit of eBay a few months ago to thin out a reasonable sized area of the panel to make either a high-frequency portion of the panel or nearly a full-range panel.

A smaller voice coil also plays a large part to improve high frequency extension. Remember, as the length of the frequency waveform equals or is less than the voice coil diameter, the gap within the exciter and the panel act similar to an oil can effect.

I have an old post over at AC that links to a video from Tectonic Audio. So for better sound quality a thinner (and better suited material for HF) material should be used and for best HF extension, a smaller voice coil exciter should be used. I have 4 of the Dayton Audio DAEX19SL-4 exciters and pair of Tectonic Elements TEAX19C01-8 exciters for this purposes and a load of small valued caps to passively high-pass these smaller exciters to make a balanced panel.

Planning a simpler 2 panel with a high-power exciter on the lower panel portion and a thinned top panel with a smaller exciter. Both run full-range to begin but if that doesn't work as well as I hope a single panel divided into 3 areas would be the next step.

Have all the exciters and cross-over components... just need to get down in the shop and get this started. Just been hemming and hawwin' over panel material to use. XPS sounds pretty good but there is a slight coloration that has bugged me since switching from the KEF to the panels. Still wondering if a good quality EPS is better route given all the work that will go into this?!? Sedge over at AC has listened to both and prefers the EPS... so close to pulling the trigger... ahhhhhhh

I too prefer the sound/tone of the EPS over the XPS. Like I said in my above post the EPS seemed to be more flexable while the XPS more stiff and the EPS did not have as much of a nasal higher pitched sound to it like the XPS.

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

On the AC thread someone used a golf ball to make an indention in the exciter area, maybe a kitchen bowl pressed into the foam would be about the correct diameter and depth?

Thinking a groove with some glue/silicone, etc. place in it could be acting as damping which may be serving nearly the same purpose as the 'sound bridges'.

Yes, I do think panel thickness plays a significant role in the sound.

A golf ball sounds like it could work as the foam material is soft enough. I guess one can use anything if it works it works as I used a set 2 inch circular saw bit and used my drill to 1/2 inch and dug out the parts in the middle then smoothed it out with 100 grit sand paper.

I also believe the glue/silicone could act as sound bridges I will be experimenting with that technique also.

[Gary.M]

H Frame woofer to add to DML

As I work on preparing panels I've also been looking at open box woofer options. I don't know how the sensitivity of the DML panel will come out so I wanted a woofer with lower efficiency so that I can pad down the DML to match if necessary. Using Martin King's Mathcad sheets I worked up this H frame design. It extends from about 30Hz to 250Hz. The woofer is from parts Express and is very affordable. It has been used in the Manzanita - Ultra OB speaker with success. GRS-15PF.

I've posted some screen captures with the details if anyone wants to try this.

[rmeinke]

Re: DIY Flat Panel Speaker Love

A golf ball sounds like it could work as the foam material is soft enough. I guess one can use anything if it works it works as I used a set 2 inch circular saw bit and used my drill to 1/2 inch and dug out the parts in the middle then smoothed it out with 100 grit sand paper.

I also believe the glue/silicone could act as sound bridges I will be experimenting with that technique also.

Hey UBS! If I'm not mistaken, sound bridges from Podium are plastic clips between the wood frame and the panel. Damps the panel and alters the freq. response I believe. I'll have to dig out the 6 Moons review... but its in there if you want to do some reading... its a good article IMHO.

[rmeinke]

Re: H Frame woofer to add to DML

As I work on preparing panels I've also been looking at open box woofer options. I don't know how the sensitivity of the DML panel will come out so I wanted a woofer with lower efficiency so that I can pad down the DML to match if necessary. Using Martin King's Mathcad sheets I worked up this H frame design. It extends from about 30Hz to 250Hz. The woofer is from parts Express and is very affordable. It has been used in the Manzanita - Ultra OB speaker with success. GRS-15PF.

I've posted some screen captures with the details if anyone wants to try this.

[ATTACH=CONFIG]62931[/ATTACH]
[ATTACH=CONFIG]62932[/ATTACH]
[ATTACH=CONFIG]62933[/ATTACH]
[ATTACH=CONFIG]62934[/ATTACH]
[ATTACH=CONFIG]62935[/ATTACH]

Heck yeah Gary... now your talking... good stuff and great work ma man! If you have not heard an OB speaker I think you will be really impressed.

FWIW - I use plate amps to drive my OB panels. Very nice to have the flexibility to match output levels and adjust crossover points (though you may need to use passive, inline electronic XO's from Harrison labs for example, or ??? to augment the plate amps XO... the dipole peak can cause some integration issues due to the plate's 12db roll-off) from the plate amps.

Dual 12's by GRS, as you might imagine, also work very well and when 8ohm 12's are run in parallel you will have higher sensitivity and a more narrow baffle if you have any interest in a slimmer baffle width. They won't dig quite as low but still very impressive and would require less power... making the plate amp approach ever more affordable. And with the Dayton plate amps are on sale its great timing!!

[Gary.M]

Re: H Frame woofer to add to DML

Heck yeah Gary... now your talking... good stuff and great work ma man! If you have not heard an OB speaker I think you will be really impressed.

FWIW - I use plate amps to drive my OB panels. Very nice to have the flexibility to match output levels and adjust crossover points (though you may need to use passive, inline electronic XO's from Harrison labs for example, or ??? to augment the plate amps XO... the dipole peak can cause some integration issues due to the plate's 12db roll-off) from the plate amps.

Dual 12's by GRS, as you might imagine, also work very well and when 8ohm 12's are run in parallel you will have higher sensitivity and a more narrow baffle if you have any interest in a slimmer baffle width. They won't dig quite as low but still very impressive and would require less power... making the plate amp approach ever more affordable. And with the Dayton plate amps are on sale its great timing!!

Yeah, I currently have ESL 57s and a pair of open baffles designed using Martin's worksheets. The open baffle design uses a 12 inch Eminence and a Mark Audio Alpair 7. I will be trying a design influenced by the look of the Pureaudioproject speakers with a 15inch and a DML panel.

Note that the info I posted uses a simple passive network to feed the woofer. I intend to use a passive network to feed the DML as well. I will apply some correction using Foobar and the Mathaudio DSP plugin.

[rmeinke]

Re: H Frame woofer to add to DML

Mine were also MJK inspired OB's but did veer away a bit from MJK and went active. The cost of passive components is fairly high; but being able to power the OB from a single amp is very nice indeed.

Didn't know (or forgot honestly) that you are a OB/full-range enthusiast. I love the looks of the PureAudio component baffles... the flexibility is equally attractive. :-)

[Kornbread]

Re: DIY Flat Panel Speaker Love

Hey UBS! If I'm not mistaken, sound bridges from Podium are plastic clips between the wood frame and the panel. Damps the panel and alters the freq. response I believe. I'll have to dig out the 6 Moons review... but its in there if you want to do some reading... its a good article IMHO.

That is how I also took it, they attached the panel to the frame but their main mission was to control certain resonances, hence, sound bridges. The grooves cut into the panel with damping material critically placed in them could be used as a way to control resonances.

Gary, bass without boxes sounds a little different. If you are the kind that likes your highs to sizzle and your bass to boom, it may not be for you. It's ... just ... different. I'm a fan. There were 4 15" PE IB subs crossed over, PEQ'd and driven by Behringer electronics in the shed, +/- 3db from 15-100hz at the listening position. Literally took me months to PEQ using only a RadioShack spl meter, pen and paper. Playing some material (Bach's organ works come to mind) the air actually felt like jello ... but the sound was never boomy; dry, clean, and articulate, never boomy. Neighbor move a house trailer in right next to the shed so that system is now idle.

The house system contains 2 Stereo Integrity HT-18" subs (similar specs to Dayton Ultimax) in an infinite baffle configuration. With the aid of REW they took less than 30 minutes to eq. (Caution, the HVAC system malfunctions when listening at volume and the growing cracks in the sheetrock can no longer be ignored.)

Just an FYI, IMO, subwoofers in an open/infinite baffle configuration require power and proper eq.


The Behringer Feedback Destroyer Pro dsp1124p works great as an affordable IB PEQ but the newer Behringer amps now come with a PEQ/dsp option. It works.

Although I have not tried any of the typical OB sub configurations (main theater speakers are OB configuration original Carver Amazing Loudspeaker) I'd be happy to assist if you have any IB questions.

These site may prove useful in IB sound:

Cult of the Infinity Baffled http://ibsubwoofers.proboards.com/

Room EQ Wizard http://www.roomeqwizard.com/

http://www.hometheaterforum.com/topic/161595-infinite-baffle-guysa-few-questions/

Carver Amazing Loudspeaker+home theater



The huge Carvers make the 18" subs look small. The subs are normally covered by a printed burlap overlay that blends in well with the room.

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Today I bought a 4X8ft sheet of 1 inch EPS at Lowes. I cut them 2X4ft. just to test it out raw, and I prefer these over the XPS for there warmer tones. These might not be the best quality EPS but untill then these will do just fine for me lol. I also bought some 1X2 inch 6ft long wood to make my frame. The fun will continue tomorrow if I am not exhausted or burnt out by then LOL

[Fshow]

Re: DIY Flat Panel Speaker Love

My room was like that too when playing my Bertagni speakers as I turned up the volume they didnt seem to get much louder/richer sounding even up to -20db on my receiver but as soon as I put some absorbtion (yoga mats/weight mats at ross lol) panels directly UNDER the bertagni speakers the sound tighten up and became much fuller/richer sounding even at -30db on my receiver. I also put some sound absorbtion panels in the back of the room which made it sound even better as for the sides I use curtains to cover the window on one side of the room and another curtain to cover my sliding door closet which is on the other side which also helped a bit. I did not however put any absorbtion material in the front area of the room where the Bertagni speakers reside at as it seemed to diminish its unique sound panel richness, as I feel the bertagni speakers uses the rear wall as sound reinforcement for that fuller effect. All this just goes to show yawl how serious or you could call it "obsessed", I am with these flat panel speakers. lol

Hi UB.

That is some very good information. I have some diffraction panels in the back of the room but what I really need is some absorbtion. The room is not quiet enough. The fact that you have experience with the Bertagni's gives me a good starting point. The panels are really sounding good and I think some sound absorbtion is my next line of attack.

Thanks
Fred

[rmeinke]

Re: DIY Flat Panel Speaker Love

Today I bought a 4X8ft sheet of 1 inch EPS at Lowes. I cut them 2X4ft. just to test it out raw, and I prefer these over the XPS for there warmer tones. These might not be the best quality EPS but untill then these will do just fine for me lol. I also bought some 1X2 inch 6ft long wood to make my frame. The fun will continue tomorrow if I am not exhausted or burnt out by then LOL

Hi UBS! Is this really true? Cheap EPS was one of the first materials I tested and it did not sound good at all. Very thin and had a crinkly sound to it...a coloration not unlike you hear when you twist or rub the panel with your hand!t?

The stuff I test may have been from either Lowe's or HD and didn't even really have a flat surface. Looking back, that alone probably doesn't allow it to sound good as the exciter doesn't make a solid bond to the panel. Also, IIRC, the exciter itself contributed considerably to the sound... as if the panel itself wasn't generating the output?!?

Can you post pics of the panel?

Also, just curious, how are you listening to these if they are not yet framed? interested to hear how you are listening to them.

Cheers!
Rich

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hi UB.

That is some very good information. I have some diffraction panels in the back of the room but what I really need is some absorbtion. The room is not quiet enough. The fact that you have experience with the Bertagni's gives me a good starting point. The panels are really sounding good and I think some sound absorbtion is my next line of attack.

Thanks
Fred

This makes perfect sense that the room plays a significant role (like any other speaker) in the overall performance. Not a surprise I suppose.

When I first started building panels, I listened in my smaller dedicated listening room. I didn't care for them and almost gave up... very close to go back to my open baffles. It wasn't until I took them into the living room, pulled out 4-5 feet into the room, did I really start to like the presentation and began to hear the magic in these panels.

Fred, your brother in law has it right. Can't be all absorption... has to have some diffraction and reflection as well... just like open baffle speakers. All absorption will remove more high frequency energy and make them sound dull and bass heavy. Overall balance will suffer.

Interested to hear how you progress with the treatment and its impact on the sound quality!!

[Unbiasedsound]

Re: DIY Flat Panel Speaker Love

Hi UBS! Is this really true? Cheap EPS was one of the first materials I tested and it did not sound good at all. Very thin and had a crinkly sound to it...a coloration not unlike you hear when you twist or rub the panel with your hand!t?

The stuff I test may have been from either Lowe's or HD and didn't even really have a flat surface. Looking back, that alone probably doesn't allow it to sound good as the exciter doesn't make a solid bond to the panel. Also, IIRC, the exciter itself contributed considerably to the sound... as if the panel itself wasn't generating the output?!?

Can you post pics of the panel?

Also, just curious, how are you listening to these if they are not yet framed? interested to hear how you are listening to them.

Cheers!
Rich

Mine was from Lowes they sell it in 4X8ft sheets with both sides protected by a plastic film that is meant to peel off when ready to use. There was a 2 inch thick and a 1 inch thick panel but I preffered to try the 1 inch panels first to get a better assesment of it compared to the pink xps panels. I took it home and cut it into (3) 2X4ft panels and (2) 2X2 just to compare it to the pink xps panels. Using the eps panels raw without any modifications or treatments right off the back I preferred the warmer tones of the eps over the xps. Dont get me wrong though the xps sounds pretty good too but I just prefer the warmer tone of the eps I guess its more of preference then which one is better, its kind of like comparing paper cones/domes to aluminum/metal cones/domes. Out of all the materials Ive tried though I have to say the xps and the eps have the most energy transfer meaning they are louder then other materials as it seems more vibrations are getting through the panels or the panels itself vibrate more due to there softer flexible material. As I type my eps panels is drying from the glue/water treatment, I will see how it sounds tommorrow for a even better comparison.

I have tried listening to them on all types of things including chairs to yoga blocks and every thing else inbetween except for a frame. I also used double tape on the back of the exciter and stuck them on many different things and I even got yelled at for doing so LOL.

[rmeinke]

Re: DIY Flat Panel Speaker Love

Hey UBS!!
The EPS I had was in a 1'x4' sheet (.75" thick?), very course and the expanded poly pieces had a tendency to fall apart when you attempted to sand the edges. The surface was not flat... very mottled. Could not even sand it smoothly.

Sounds like the EPS you are using is good quality. I checked 2 Lowe's in the area and I've had no luck so will be looking to see if I can order on line and have it shipped to a local store... the EPS you have really sounds like a good material!

Could you snag a quick phone pic of your EPS? If I could take a peek at the material before ordering it,that would be excellent and very appreciated!

Thanks,
Rich

[Gary.M]

Re: DIY Flat Panel Speaker Love

Hey UBS!!
The EPS I had was in a 1'x4' sheet (.75" thick?), very course and the expanded poly pieces had a tendency to fall apart when you attempted to sand the edges. The surface was not flat... very mottled. Could not even sand it smoothly.

Sounds like the EPS you are using is good quality. I checked 2 Lowe's in the area and I've had no luck so will be looking to see if I can order on line and have it shipped to a local store... the EPS you have really sounds like a good material!

Could you snag a quick phone pic of your EPS? If I could take a peek at the material before ordering it,that would be excellent and very appreciated!

Thanks,
Rich

What you describe as EPS sounds just like low grade XPS (expanded polystyrene) For EPS (extruded polystyrene) look for good insulation material. That's one of its prime uses.