https://www.erinsaudiocorner.com/driveunits/tectonic-elements-tebm35c10-4-miniature-bmr-driver/
Round enclosure, 6 opposing drivers would be interesting.
When they are close together and driven with identical signal there’s noticeable comb filtering when using pink noise, but not with music.
Round enclosure, 6 opposing drivers would be interesting.
When they are close together and driven with identical signal there’s noticeable comb filtering when using pink noise, but not with music.
It is indeed possible to place the drivers in a smaller enclosure. That will then have a different shape, f.i. a truncated tetrahedron. Volume then can be reduced by a factor of 4. But Qtc becomes then undesirable high. So you have to find extra voulume elswere or take smaller dirvers like the 2" DMA58-8.
Interesting suggestion, maybe I'll give it a try. However, I really have no idea what to expect.
What do you mean by measuring with both poles ?
Might well work. Is this your own hardware ?
But I don't think this is an omni directional speaker and is therefore outside the scope of my project.
Also the omni's I made it give excellent sound repoduction despite the combing. The problem I want to solve is the not optimal stereo separation.
It’s not really round, it is a dodecahedron. A dozen pentagons with a driver sitting in each one.
dave
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Once 3 indirekt speaker in the phase(exsisting) and another time out of phase. In the phase You should have combs and out of phase combs should disappear(almost). You should try 6 dB crossover 200Hz? for direct and 1-2kHz for indirekt speaker, as You need attenuation for indirekt speakers You can wire this in parallel with series resistor and with parallel direct speaker that should be 4 Ohm. Measure that with all room modes(no time gate) and above 1kHz with indirekt speakers Spl should be maximal 2dB higher with the same linearity as without ambiental. Measure on listening position - You need room reflections for correct result.
Hmmm i like the idea of letting the motor stick out for increased heat dissipation. I haven’t smoked a coil yet but it definitely have happened.
I never seen this brand/model before.
The test signal is usually loud pink noise and can in some cases be on for an extended period of times if we are measuring the sound transmission thru walls or floor/ceiling.
From the REW measurements, I noticed that at certain orientations of the omni, the SPL function is quite flat up to 4.5 kHz and plunges steeply downward above that.
photo taken from mic position
If we add tweeters we could get an acceptable SPL in at least one direction, that is towards the listener at the sweet spot.
We can try mounting tweeters on the four empty hexagons. In doing so, the speaker still meets the criteria for an omnidirectional speaker.
Artist impression of the simulated configuration.
for the DA175-8 the factory on-axis fdr was used.
for the DMA70-8 the SPL measured with REW is used (see above) + 6 dB
for the ND13FA-4, the factory 30-degree off-axis fdr was used
I simulated the following circuit with all drivers in the origin:
The resulting SPL from the simulation already looks very promising. The energy frequentie response is also pretty beefed up.
However, even if this approach works in practice, I expect there is still much to be done to achieve optimal results. This means a lot of measuring to find the best orientation for the omni and optimizing the filter. But it could be a winning approach.
Note: as an alternative, consider a tweeter on each of the six squares.
photo taken from mic position
If we add tweeters we could get an acceptable SPL in at least one direction, that is towards the listener at the sweet spot.
We can try mounting tweeters on the four empty hexagons. In doing so, the speaker still meets the criteria for an omnidirectional speaker.
Artist impression of the simulated configuration.
for the DA175-8 the factory on-axis fdr was used.
for the DMA70-8 the SPL measured with REW is used (see above) + 6 dB
for the ND13FA-4, the factory 30-degree off-axis fdr was used
I simulated the following circuit with all drivers in the origin:
The resulting SPL from the simulation already looks very promising. The energy frequentie response is also pretty beefed up.
However, even if this approach works in practice, I expect there is still much to be done to achieve optimal results. This means a lot of measuring to find the best orientation for the omni and optimizing the filter. But it could be a winning approach.
Note: as an alternative, consider a tweeter on each of the six squares.