Compression Drivers without Horns?

[NV&H]

I don't recall their name, but there's a speaker company in existance that uses TAD drivers in a two-way configuration. The high frequency compression driver is just bolted to the top of the woofer cabinet facing the world with no horn attached.

Obviously, the horn artifacts would be missing, but does that mean it would sound better? In such a configuration, I wonder about efficiency loss, dispersion weirdness, and frequency response anomolies.

So I'm wondering, have any of you ever listened to a compression driver without the horn?

[GM]

Yes, drivers with a built-in small conical initial flare make great tweeter horns from ~5 kHz-up, though I chose to mount them to a small piece of 3/4" no-void plywood or hardwood and round over the hole to reduce reflections back to the throat and extend its BW a bit.

[DorinD]

These?
http://www.deepaudio.net/

[robertG]

It works, but it won't go very low. The 5kHz figure is probably correct.

[AndrewT]

it's a treble driver.
Why would one want it to do mid duty?

[GM]

Huh?! Typical compression drivers (including the 4001) are BP4 alignments designed for mids and treble with the gain BW defined by the horn's acoustic loading. Since this one has a very short built-in one, it's strictly a super tweeter without any horn extension to 'unlock' some more of its usable BW.

[Pano]

It's hard to argue with the driver quality, but the implementation seems a bit -- odd.

How big an under-lap would you have at that crossover point? No mention of that or even the actual dimensions of the box. Or did I miss it?

[Robh3606]

I am not sure what the response is for the Tad with its Be diaphram or where the mass break point is It would be interesting to see what one measured like and how much of a CD type compensation would be needed for flat response to say 1.5-2K which is probably as high as they take the woofer. The polar response must be a mess at the crossover point.

Rob

[GM]

Indeed! I just assumed the main driver was a really wide BW one. This doesn't seem viable unless XO'd out at the ragged edge of the 1601's break-up modes and even then I imagine it would be marginal, but surely we're missing something. I mean they can't afford to replace such an expensive diaphragm under warranty with any sort of regularity.

One thing's for sure though, their marketing hype about the 4001's response is misleading at best since the sharp exit transition causes plenty of well known problems.

[ScottG]

Originally posted by GM
Indeed! I just assumed the main driver was a really wide BW one. This doesn't seem viable unless XO'd out at the ragged edge of the 1601's break-up modes and even then I imagine it would be marginal, but surely we're missing something. I mean they can't afford to replace such an expensive diaphragm under warranty with any sort of regularity.

One thing's for sure though, their marketing hype about the 4001's response is misleading at best since the sharp exit transition causes plenty of well known problems.

I'd bet that the midbass driver is run with out a lowpass filter. Looking over the website you'll note that the loudspeaker *must* be listened to on-axis.. While it likely is important for the top octave of the compression driver, its far more important for the midbass driver and anything approaching linearity. I'd expect a natural sp-loss starting around anywhere from 1.5 to 3 kHz.. (with the safer bet being closer to 1.5 kHz).. Based on that conjecture I wouldn't be surprised to see a 4th order electrical (LR) around 2.2-2.5 kHz for the compression driver.

I also wouldn't be at all surprised if they didn't care about freq.s above 12 kHz.