DIY Flat Panel Speaker Love

[Unbiasedsound]

Like I said before a good sounding DML panel is all design dependent as the better ones design the better the sound. If one knows how DML's actually work and function its easy to figure out how to tackle transient response. Its pretty similar to conventional cone full range drivers like Fostex, tang band, mark audio etc. Most of those drivers size are 8inchs and under because its all about physics. Even DML's have to abide by those laws if you want them to sound right. Most people who build DML start off with a 2ft. (pink) panel then go to 4ft. and then max 8ft. They dont even make 4ft. or 8ft conventional cone drivers and for good reason especially if using it as full range. This is why I stress smaller panel size as DML's are very similar to conventional cone drivers.

Also did you listen to my sound clip, and if so what are your thoughts?

[zx82net]

No, I have not.

Blurred?

I've not heard good ones or seen transient response measurements, so I have no authority here. People make amazing claims for them, but transient response seems like it must be a challenge: The radiating area is very high, leading to low displacement (a very good thing), the total moving mass is enormous compared to a normal tweeter (a bad thing), and you have to deal with propagation delay across the surface of the panel (a bad thing). I wonder how these things bear out in practice. Since material properties of the favored panel materials are undocumented and variable, I doubt modeling helps much.

[Unbiasedsound]

When listening to my recording I noticed the treble is a bit hot but I tend to like it but if I want to I can easily reduce the treble. With conventional cone drivers usually the only way to change the frequency response is to change the crossover. With DML's you can use other techniques. I've mentioned before that Shelly Katz Podium speakers he uses damping on the spine in which you can tune your DML panels to your taste. I use the frost king foam cut into 1/2-1/4inch pieces placed on the spine. If you do not use a spine you can also place the foam piece directly on the back of the exciter magnet. You can also do it the conventional way by using a 0.05mh inductor and it will smooth out the treble.

[Unbiasedsound]

I made a recording of my small Sat.DML panel with powered (conventional cone) subwoofer playing. Yes I know the sub gain is to high as I had some larger panels hooked up and forgot to dial the sub back when hooking up these smaller DML panels before recording. Its recorded from my cell phone so the recording is not that great.

These small dml panels are my entry level design using a single exciter run full range without any crossover parts.

Sawna - YouTube

[Unbiasedsound]

No, I have not.

Blurred?

[zx82net]

Serious question, has anyone seen any real transient response metrics for DMR flat panels?

They have to be blurred by the speed of the transverse wave propagating across the panel, don't they?

[Eipromb]

If you can get at least 1ft. it will be good enough.

Are you planning on using a powered sub with the panels?

I'll be running something for the low end, though I haven't decided what yet. I have an unused DSP-408 lying around, so I'm thinking I could use that to run separate mid-woofers on each channel, or a single sub or both. The limiting factor is primarily the amount of space I have in the room.

[Unbiasedsound]

Haha this will be tough, it seems typical room sizes in the city where I live are barely larger than 4ft these days.

If you can get at least 1ft. it will be good enough.

Are you planning on using a powered sub with the panels?

[Unbiasedsound]

While I do plan to mount at roughly ear level, I’m curious about this. Is this general advice or something specific to DMLs? I thought one of the benefits of DMLs was their ability to sound well off axis. Ignoring floor/ceiling reflections (let’s pretend I’m sitting in an anechoic chamber), would DMLs perform better/ worse/ the same as a tradition cone that was close to the floor?

This is general advice but the reason I mention this is because I see to many people place there DML speakers way up high. Although DML's sound good off axis they sound better on axis like any other speaker. They would perform better then a traditional cone because of the diffused nature of there reflections meaning the reflections are not as prominent.

[Eipromb]

DML's should be a minimum of a foot away from the rear walls and ideal or optimum distance is around 2ft.-4ft. also depending on the size of the room.

Haha this will be tough, it seems typical room sizes in the city where I live are barely larger than 4ft these days.

[Eipromb]

Also optimal or ideal height placement of a DML panel should be around ear level give or take a few inches up or down.

While I do plan to mount at roughly ear level, I’m curious about this. Is this general advice or something specific to DMLs? I thought one of the benefits of DMLs was their ability to sound well off axis. Ignoring floor/ceiling reflections (let’s pretend I’m sitting in an anechoic chamber), would DMLs perform better/ worse/ the same as a tradition cone that was close to the floor?

[Unbiasedsound]

Technically DML's are not suppose to be mounted on the wall due to the sound radiating from both the front and the back. Its the same concept why Open Baffle/Bipolar speakers shouldnt be mounted on the wall.

Also there is a big difference in sound between no foam at all and adding 1-2inch foam strips with 1-2 inch gaps.

DML's should be a minimum of a foot away from the rear walls and ideal or optimum distance is around 2ft.-4ft. also depending on the size of the room.

Again I am not saying you cant do it but if you do the sound wont be the same as DML's actually use rear wall reflections to there advantage. This is the reason DML's are not normally used in a enclosure.

Also optimal or ideal height placement of a DML panel should be around ear level give or take a few inches up or down.

[Eipromb]

Instead of a continuous foam strip all around the panel you can cut them into 1-2inch strips and leave 1-2inch gaps in between like on AllenB's panels. This will let some sound pass through the edges making them sound fuller/holographic/airier. Its up to you though as it is personal preference as you may or may not like the difference in sound.

When I was building it, I tested the panel just hanging/open. It did sound holographic, almost as if the sound was coming from behind the panel - but I didn’t like the sensation of it though.

As it is now (on the floor) it’s still plenty airy and sounds so much better than just a hanging panel. The only thing I haven’t tested yet, is with the whole speaker mounted on the wall. I might need to revisit your idea of the gaps if it ends up sounding too constricted.

[Unbiasedsound]

Instead of a continuous foam strip all around the panel you can cut them into 1-2inch strips and leave 1-2inch gaps in between like on AllenB's panels. This will let some sound pass through the edges making them sound fuller/holographic/airier. Its up to you though as it is personal preference as you may or may not like the difference in sound.

[Eipromb]

After doing a ton of reading and lots and lots of trial and error, I managed to get my version of a DML working.

Kudos to Unbiasedsound for all the advice he’s shared on the forums. They were invaluable to my build.

My 2 main requirements were to appease my better half that didn’t want “big ugly speakers” around lol, but also to sound good enough for me to enjoy.

I CNC’d a frame from MDF that would carry a 3D printed mount for the exciter. Still a bit of work left to paint and make it look pretty enough to mount, but functionally it’s working. The rear of the foam was also routed similar to the Bertagnis speakers Unbiased posted. The routing made the lower end MUCH more present, you could almost get away without a sub during nighttime listening.

Here are pics, but please ignore all the dust everywhere! It’s a mess in the den.