DIY Flat Panel Speaker Love

[Unbiasedsound]

Hey Captainjack115 , I wish you a speedy recovery and get well soon.

[Kornbread]

I've been out of the loop for a while due to health issues and hospital stays, I hope to get back to playing with DML's soon.


I still think multiple exciters need to be on separate panels to increase power handling and maximum high frequency response.

In the absence of very accurate simulations my guess is it's nearly impossible to correctly place multiple exciters to achieve the desired frequency response on one panel. It seems all but too easy for one placement to cancel, or enforce, another node from another placement.

On the flip side. If we could accurately predict what placements yielded what responses ...

[Unbiasedsound]

In the absence of very accurate simulations my guess is it's nearly impossible to correctly place multiple exciters to achieve the desired frequency response on one panel. It seems all but too easy for one placement to cancel, or enforce, another node from another placement.

On the flip side. If we could accurately predict what placements yielded what responses ...

I respectfully disagree as my Bertagni speakers have proven to me other wise that multiple exciters can be used on one panel to achieve a desired frequency response. This is achieved by adding grooves and channels as well as different thicknesses on the back side of the panel surface (where the exciters reside) to help minimize certain frequencies from canceling each other out, while at the same time enforcing certain desired frequencies. Even the half clam shell/crater on the front surface of the panel helps to augment the higher frequencies.

I also wanted to add that when using EPS I have noticed that each side of the eps panel has a different sound/ tone. I have noticed this from using the lower grade eps from lowes as well as the high quality grade of eps that I special ordered. One side of the eps will seem brighter while the other side will seem less bright. Which side you prefer is your own preference but I prefer the brighter sounding side.

[Kornbread]

[QUOTE=Unbiasedsound;n1279428]

I respectfully disagree as my Bertagni speakers have proven to me other wise that multiple exciters can be used on one panel to achieve a desired frequency response. This is achieved by adding grooves and channels as well as different thicknesses on the back side of the panel surface (where the exciters reside) to help minimize certain frequencies from canceling each other out, while at the same time enforcing certain desired frequencies. Even the half clam shell/crater on the front surface of the panel helps to augment the higher frequencies./QUOTE]

Then I will have to respectfully disagree with your respectful disagreement. Although I have never seen a Bertagni in person, from your description it sounds like much effort had to be taken in order to achieve the desired sound. Using partial cuts, channels, different thicknesses, indentations, placements, size, etc; all have an effect on sound. I'm guessing here, but wouldn't there be literally thousands of combinations of these combinations of modifications yielding literally thousands of different sound possibilities? IMO, Bertagni did their research, and plenty of it. Much too complicated to get it exactly right for the DIY'r without their knowledge base or some type of simulation to work with.

YMMV.

[Unbiasedsound]

[QUOTE=Kornbread;n1279528]

I respectfully disagree as my Bertagni speakers have proven to me other wise that multiple exciters can be used on one panel to achieve a desired frequency response. This is achieved by adding grooves and channels as well as different thicknesses on the back side of the panel surface (where the exciters reside) to help minimize certain frequencies from canceling each other out, while at the same time enforcing certain desired frequencies. Even the half clam shell/crater on the front surface of the panel helps to augment the higher frequencies./QUOTE]

Then I will have to respectfully disagree with your respectful disagreement. Although I have never seen a Bertagni in person, from your description it sounds like much effort had to be taken in order to achieve the desired sound. Using partial cuts, channels, different thicknesses, indentations, placements, size, etc; all have an effect on sound. I'm guessing here, but wouldn't there be literally thousands of combinations of these combinations of modifications yielding literally thousands of different sound possibilities? IMO, Bertagni did their research, and plenty of it. Much too complicated to get it exactly right for the DIY'r without their knowledge base or some type of simulation to work with.

YMMV.

Kornbread quote>my guess is it's nearly impossible to correctly place multiple exciters to achieve the desired frequency response on one panel.

It seems that everything you said sounds like you are agreeing with me? It is possible to have multiple exciters on one panel to achieve the desired frequency response when utilizing bertagni's methods. My simulation is comparing it directly to my bertagnis speakers and trying to match there sound. Using just one exciter per panel does not even come close to the bertagnis sound. Utilizing 2 exciters on a panel gets them a bit closer. Utilizing the half clam shell crater in the front that bertagni uses for the high frequency brings the sound even closer.....By adding channels and different thicknesses brings the sound even closer. Adding a frame to hold the exciters in place with some kind of surround support for the outer edges of the eps panels brings the sound even closer. By using higher quality EPS brings the sound even closer...By using 2 different types of exciters brings the sound closer, by knowing which side of the eps has a different tone brings the sound closer... by using a certain type of skin on the surface of the eps panel brings the sound even closer, by using a Equalizer brings the sound even closer....with so many factors involved there are so many possibilities to achieve a desired frequency response by using more then one exciter on a panel. Each time I am getting closer but I have a lot more to experiment with before they are exactly like my Bertagnis. If it were nearly impossible for anyone using more then one exciter on a panel then we should just all give up. LOL

[Gary.M]

From the description the Bertagnis are not a single panel. The partial cuts, grooves etc will make it behave as if it were a number of separate panels, with perhaps, or not, some interaction between, or leakage from, one section into others.

[Unbiasedsound]

From the description the Bertagnis are not a single panel. The partial cuts, grooves etc will make it behave as if it were a number of separate panels, with perhaps, or not, some interaction between, or leakage from, one section into others.

The Bertagnis are a single panel, its the grooves and channels etc. that make the panel behave like a separate panel but at the same time it can enforce certain desired frequencies as well and that is how one can utilize more then one exciter on a single panel to achieve a desired frequency response/sound when using Bertagnis method.

I ordered more exciters to test out to see if the smaller coil exciters would have a higher frequency response like the 19mm dayton and the 13mm tectonics.

[Gary.M]

The Bertagnis are a single panel, its the grooves and channels etc. that make the panel behave like a separate panel but at the same time it can enforce certain desired frequencies as well and that is how one can utilize more then one exciter on a single panel to achieve a desired frequency response/sound when using Bertagnis method.

I ordered more exciters to test out to see if the smaller coil exciters would have a higher frequency response like the 19mm dayton and the 13mm tectonics.

You missed my point.

[Gary.M]

At last I've had a few minutes to make a few measurements. I have twin cush cardboard doped with water based floor finish. They were a little limited in HF, not much above 10kHz, and quite lumpy unless you looked at 45 deg off axis when they improved apart from the HF.

My other panel material is 3mm bamboo plywood, doped the same. Here it is on axis.

[Gary.M]

And here is the same panel 45 deg off axis. Both measurements are at 1 metre. The exciter is the DAEX25FHE-4. As I'm looking for something that will work from 200Hz approx on up, this might do the job.

[Gary.M]

Note the Y axis is 5dB per division.

And here is the same panel 45 deg off axis. Both measurements are at 1 metre. The exciter is the DAEX25FHE-4. As I'm looking for something that will work from 200Hz approx on up, this might do the job.

[ATTACH=CONFIG]n1279830[/ATTACH]

[Unbiasedsound]

Note the Y axis is 5dB per division.

I still dont get your point as I am not knowledgeable in those schematics but I did just order a pair of the DAEX25HE-4 since they are on sale.

[captainjack115]

In the absence of very accurate simulations my guess is it's nearly impossible to correctly place multiple exciters to achieve the desired frequency response on one panel. It seems all but too easy for one placement to cancel, or enforce, another node from another placement.

On the flip side. If we could accurately predict what placements yielded what responses ...

I totally agree with you on exciter placement. My use of multiple exciters consisted of four panels mounted vertically, one exciter per panel. It worked pretty well, at the time high power exciters weren't available to the DIY community. I still required bass augmentation.

[Tin Ear]

I've been out of the loop for a while due to health issues and hospital stays, I hope to get back to playing with DML's soon. I still think multiple exciters need to be on separate panels to increase power handling and maximum high frequency response.

Certainly hope you are on road to recovery.

[Unbiasedsound]

Anyone ever try the Duratex coating by partsexpress used to paint speaker cabinets? I am thinking about trying a small can to see how that skin would sound on the front of the panels.