u/ikel0s

Hey guys,

Wanted to share a project I just wrapped up as i think DML technology is completely overlooked for cheap speakers with insane reproduction qualities when paired with the right sub. This is version 1 which was more of a proof of concept but I'm still more than happy with the results. If you are interested in reading more or even build a pair yourself you can find the full project report where I explain my design philosophy, the detailed build plan, calculations, measurements, XO design and listening impressions in the diyaudio forum post i linked below.

The main goal with this build was to see if I could get a genuinely natural, "in the room" presence for acoustic instruments like guitars, violins, and vocals. My idea was to match the physical way these instruments produce sound with the operating principle of the speaker itself. Instead of forcing a rigid cone to move like a piston, my DML uses a light wooden structure, which feels way closer to how a real instrument works.

Here is a quick look at how I tried to lean into that instrument concept:

• The Shellac Treatment: I used 2 mm birch aircraft plywood (35x50 cm) driven by a pair of Xcite XT32-4. To balance out the lack of edge damping, I finished the panels with four coats of blonde shellac using a traditional French polish pad. The goal was to borrow from violin craftsmanship, introducing internal material damping through the wood grain to smooth out high frequency harshness naturally.
• Zero Edge Damping: I went with a completely free suspended setup, hanging the panels from solid pine frames using 0.3 mm fluorocarbon fishing line. I wanted to avoid edge loading or choking the boundary energy.
• Exciter Placement: To avoid hitting the nodal lines of dominant low order bending modes, the exciter is glued precisely at 3/7 x 4/9 from the top inner corner (more on this in the doc).

For the low end, I’m running them with a dual 12' (SB acoustics sb34swpl76-4) sealed sub, crossing over electronically at 180 Hz (24 dB/oct Linkwitz-Riley) via DSP(way too high for the sub). Because of the panel's inherent dipole phase lead, I dialed in about 5.25 ms of delay on the tops to get them to sum properly, and the acoustic crossover seems to be locking in.

If you can live with the lower mid compromise, which is also dissected thoroughly in the doc, the spatial presentation is stunning. On acoustic tracks, jazz, and vocals, the panels completely disappear. The directivity stays nearly uniform out to 90° and beyond, creating this massive, diffuse, 3D cloud of sound rather than beaming music at your face. Transients are lightning fast.

Would be glad for any feedback, tips or maybe critique on some of the measurement methodologies and mathematical reasoning as I'm in no way qualified for any of this, hope you enjoy the read

I uploaded two videos showcasing the speakers here(I hope this is allowed) CAUTION this was recorded with my phone: https://drive.google.com/drive/folders/1p2z1qkNnS65w76PlD3ZCu5nl7TbvRWDh

Cheers (:

https://www.diyaudio.com/community/threads/kastlers-dml-ver-1-a-shellac-finished-birch-ply-experiment.441910/

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Hey guys,

Wanted to share a project I just wrapped up as i think DML technology is completely overlooked for cheap speakers with insane reproduction qualities when paired with the right sub. This is version 1 which was more of a proof of concept but I'm still more than happy with the results. If you are interested in reading more or even build a pair yourself you can find the full project report where I explain my design philosophy, the detailed build plan, calculations, measurements, XO design and listening impressions in the link i posted below.

The main goal with this build was to see if I could get a genuinely natural, "in the room" presence for acoustic instruments like guitars, violins, and vocals. My idea was to match the physical way these instruments produce sound with the operating principle of the speaker itself. Instead of forcing a rigid cone to move like a piston, my DML uses a light wooden structure, which feels way closer to how a real instrument works.

Here is a quick look at how I tried to lean into that instrument concept:

• The Shellac Treatment: I used 2 mm birch aircraft plywood (35x50 cm) driven by a pair of Xcite XT32-4. To balance out the lack of edge damping, I finished the panels with four coats of blonde shellac using a traditional French polish pad. The goal was to borrow from violin craftsmanship, introducing internal material damping through the wood grain to smooth out high frequency harshness naturally.
• Zero Edge Damping: I went with a completely free suspended setup, hanging the panels from solid pine frames using 0.3 mm fluorocarbon fishing line. I wanted to avoid edge loading or choking the boundary energy.
• Exciter Placement: To avoid hitting the nodal lines of dominant low order bending modes, the exciter is glued precisely at 3/7 x 4/9 from the top inner corner (more on this in the doc).

For the low end, I’m running them with a dual 12' (SB acoustics sb34swpl76-4) sealed sub, crossing over electronically at 180 Hz (24 dB/oct Linkwitz-Riley) via DSP(way too high for the sub). Because of the panel's inherent dipole phase lead, I dialed in about 5.25 ms of delay on the tops to get them to sum properly, and the acoustic crossover seems to be locking in.

If you can live with the lower mid compromise, which is also dissected thoroughly in the doc, the spatial presentation is stunning. On acoustic tracks, jazz, and vocals, the panels completely disappear. The directivity stays nearly uniform out to 90° and beyond, creating this massive, diffuse, 3D cloud of sound rather than beaming music at your face. Transients are lightning fast.

Would be glad for any feedback, tips or maybe critique on some of the measurement methodologies and mathematical reasoning as I'm in no way qualified for any of this, hope you enjoy the read

Cheers (:

here you can find the full documentation file: https://drive.google.com/file/d/10DS4ADZrWWLcUxsUpfyRiDSD5kZAen7v/view?usp=sharing

EDIT: I uploaded two videos showcasing the speakers here(I hope this is allowed) CAUTION this was recorded with my phone: https://drive.google.com/drive/folders/1p2z1qkNnS65w76PlD3ZCu5nl7TbvRWDh

A lot of things have changed since last time, I'm open for any feedback or discussions (: all in all i spent about 900€ here are the specs:

Specs:

Tops: Nubert nuwave 8

Sub: Custom built 2x12" (sb34swpl76-4) closed enclosure

DSP:* Thomann dsp 4x4 mini pro

Amp Tops: Bittner basic 800

Amp Sub: ACR A700 (rebrand of Bell PA-8022X) bridged

Vinyl Preamp: Graham slee special edition 2

Crossover & Sub EQ:

The crossover is set at 110hz with 24db/oct LR filters. furthermore i added a taste eq which includes a bass boost in the low frequencies. With a 7db boost around 35hz, the subwoofer reaches 25hz without a problem (measured across 3 different listening positions). There is also a sharp notch at 42hz to kill a nasty room mode.

Tops EQ:

For the tops i added a slight boost of +1.5dB around 700hz and +1.5dB at 5khz, plus a +1.7dB high shelf at 13khz (mostly to compensate for the old ferrofluid tweeters). I've added the eq bc the nubert speakers are really neutral which i don't really enjoy for normal listening.

For about 900€ total the clarity and deep bass control even at high volumes is crazy imo.

What do you guys think of the 110hz crossover point and the taste eq? Any feedback appreciated (: