Is there any consensus about whether Linkwitz LX Mini Style absorber stuffed cylindrical diffusers mounted behind OB midranges do anything beneficial for sound? It seems they are quite well hidden in the "shadow" of the magnet structure, so I can't see much energy making it into the cylinder. I made a crude set and didn't measure much difference to frequency response. Obviously, FR is only part of the story, or maybe I didn't stuff the cylinder tightly enough. However, I haven't noticed any other designs using this configuration, have they been proven to be useless?
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I'd be inclined to do some test measurments before coming to a conclusion. My guess is a larger diameter shorter length tube would work better, but not look as good.
Erin's measurements here: https://www.erinsaudiocorner.com/loudspeakers/linkwitz_lx_mini/
The mid/high polars look quite good.
Erin's measurements here: https://www.erinsaudiocorner.com/loudspeakers/linkwitz_lx_mini/
The mid/high polars look quite good.
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Yeah, pretty good null at 90 degrees. Too bad the tube provides the supporting structure for the driver, otherwise I’d try To persuade Erin to measure them without the diffuser.
I suppose the tube gives smoother directivity on the backside. I have measured only cone drivers without a tube and they are really bad - spider and motor make ugly wiggles
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I've long thought that using a metamaterial would be really great for this.
The idea would be similar to covering the entire back wall with metamaterial.
But by placing it right up against the driver, it can be more effective.
The idea would be similar to covering the entire back wall with metamaterial.
But by placing it right up against the driver, it can be more effective.
That’s an interesting speaker,
An LX 521 with a bass reflex cabinet for the woofer? Are you using dsp or?
Looks like it may be more suitable for smaller rooms. I’m considering an LX mini build. Any suggestions?
Thanks
An LX 521 with a bass reflex cabinet for the woofer? Are you using dsp or?
Looks like it may be more suitable for smaller rooms. I’m considering an LX mini build. Any suggestions?
Thanks
Interesting measurements. Thinking how such big diference is at 1khz with and without diffuser at 90deg. Looks like dipole moves to cardioid side at these frequencies. Shape of polar response changes but on axis should change a little in such case…little strange IMHO
Yeah, dsp. Two of these For 8 channels of fun:
https://www.parts-express.com/Dayton-Audio-KABD-4100-4-x-100W-Bluetooth-Amp-Board-with-DSP-325-434
With a sub woofer as well.
If you’re prepared to buy a calibrated mic and enjoy playing about, I’d suggest rolling your own vs building a straight LX mini, much more fun. 😄
I would expect the fact the side null effect is confined to low kHz range is related to wavelength and the distance between the diffuser and the cone, which is approx 10cm. I don’t think the loss of the 90 degree null is desirable. I expect the benefit, such as it is, is the minor reduction in rear energy. I measured less than 2 dB, but a different magnet structure, and a wider or more heavily stuffed pipe could increase that significantly. I don’t have the Linkwitz plans, so I don’t know how much stuffing he recommended. Mine was quite loosely filled.