OB/Cancellation Speaker Tested, and worked.

[borispm]

After messing around for a month, my Aurasound drivers came. I made a cardboard test cab for them, and I proved that the rear radiating wave can be effectively cancelled by a separate driver placed perpendicularly by listening to the space between the two drivers.

There was buzzing from the poorly made cab, but I still found excellent spacing and imaging with this set of speakers. BTW, they are meant for close field listening and not blasting, so don't feed them with extremely loud music. Anything with heavy bass with a sound pressure level of above 96dB is not recommended as this may bottom out the drivers.

[preiter]

I'd be interested to see a frequency response graph of the back vs. the front.

[InclinedPlane]

I believe tekton has already resurrected the patent for this design and as usual, claims it's the ultimate loudspeaker. But I'd like to hear more anyway.

[yyhtbs]

Does this Aura means FR? It should be woofer only~

[SilverStrings]

I have the tekton ob4.5s they definitely sound better and offer a more full range sound than the regular single drivers, I'm selling them though because bass is still not enough for watching movies and I'm getting into DIY now.

[chris661]

Good to know it's working.

I assume you'll be building a "proper" box for them, so (for the purpose of experiment), would you consider trying ported vs sealed on the rear driver?

[borispm]

@yyhtbs, they are the 3" variant, so they should be good up to 12kHz, while Aurasound claims 15kHz. I think I want a super tweeter and cross at 10kHz.

Chris, I think I'll make a proper box with 1/2" ply wood with bitumen pads inside. Porting the driver would create a nasty steep roll off around 40Hz and I'm aware the power handling problem. There's bass, but you'll need a 6dB bass boost to make them sound like 6" woofers.

BTW, with this design, off axis is not very pleasant, so they are more suitable as close field (maybe studio monitors?)

You will need a subwoofer if you listen to Mariah Carey or Madonna unless you feel safe having a 6dB boost.

[borispm]

@Inclined Plane
Yup, Tekton tried to get a patent, but it's still patent pending, so feel safe to use it for personal use. BTW, I believe this is a bit different from Tekton's patent, and to twist the design a bit, I want to try use a transmission line for the cancellation driver.

Anyway, they sound very spacious and vocals are excellent. It reveled that Madonna's albums are DSPed with some phasing tricks and as these speakers are highly directional (real monopole bass), it sometimes sound like "out of the head".

[chris661]

Boris, the transmission line idea is fantastic, provided it's long enough to give a near-infinite baffle loading to the driver (correct stuffing should help this).

Have you crossed the rear driver over? I found 2nd order LP around 400Hz good on my design a while ago.

[borispm]

I did not use a single filter. I just inverted the cancellation driver to limit the treble from the cancellation driver. For those who hate reactive elements, this is a good thing. But I still think I can try adding a filter.