Huge 2-way with 18" woofer and 2" exit compression driver?

[BHTX]

I've been thinking about this for a while. Anyone ever do this? Could be used for personal home listening, parties, outdoors, DJing, small live gigs, etc.. a tough thing to pull off, but I'm wondering what the result would be like. I'm thinking one might end up with something that sounds very similar to the typical sound of a movie cinema, but perhaps sounding a lot bigger and better in the typical listening room, plus extra low-end from room gain and a better woofer/enclosure combo.

Also, I'm aware of the problems associated with a 2" exit compression driver running above 10 KHz, but I'm curious as to just how audible it'd really be. More than anything, I think the high directivity above 10 KHz and the resulting off-axis downward slope above 8-10 KHz as a result would be more problematic than anything. But I still wonder what it'd be like.

So, a single 18" serious pro sound woofer in a large vented enclosure with a 2" exit driver mated to a large pro sound horn, digitally crossed at 400-500 Hz, 8th order lowpass on the woofer and 4th order highpass on the compression driver.

For example, here are some of the specific components I've been eyeing:
Goldwood GM-450PB 2" High Frequency Horn
Peavey 18" Low Rider Subwoofer Speaker Driver
Peavey 18" Low Max Subwoofer Speaker Driver
Choice of compression driver is still very much up in the air.

Anyway, either of the above woofers would work well in 10^3 tuned to about 30 Hz, capable of 120-123 dB continuous @ 1m before Xmax starts coming into play. I'm curious though about the frequency response of these woofers, since Peavey never seems to list measurements. They state 500 Hz and 1 KHz, but I somehow doubt they're so limited. Inductance for both woofers is fairly low too, compared to other woofers in their class.

I've used these links below as a general idea of what to expect from such a 90 degree 2" exit horn and driver combo. These horns seem very similar to that cheap Goldwood I listed above:
http://prodance.cz/protokoly/RCF_H9040_DE750.pdf
http://prodance.cz/protokoly/fh2450_de750.pdf

Speaking of the Goldwood horn, P.Audio makes an identical one for a lot more money. I'd typically stay away and flat out ignore anything from Goldwood, but this 2" horn might turn out to be a really good value.

Anyway, just contemplating, and thought I'd inquire for any thoughts and experiences regarding such a project.

edit:
Also, my biggest issue with the above is the digital crossover, in regards to volume control. Is there still not a readily available volume control with XLR outputs for DCX2496 and the likes? Why the hell not??

[pinkmouse]

I don't know those particular 18" drivers I'll admit, but I haven't heard any others I'd like run to more than 250Hz. I think a 15" would be a much better match, and still do what you want. Or stick a horn loaded 6.5" in the middle, then you can use a better CD.

[el`Ol]

Strassacker: Lautsprecher - Boxen - Selbstbau
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[BHTX]

pinkmouse:
Thanks for the input. I wonder what specifically caused the bad sound from the 18's you've experienced? I guess I was just thinking the slightly higher directivity from 500Hz-1KHz might be beneficial, plus the simplicity, no subwoofers necessary (-3dB @ 30Hz), extra wow factor, etc.

el`Ol:
Is this what you're talking about? Eggo1
Interesting indeed. Where to get a massive waveguide like that? Cost? I'm aware of the Le Cléac’h Azurahorns, if that's what it is.

Anyway, for some reason, I just find the thought of hosting tunes for a crowd or providing the sound for a small live concert, then rolling it inside the same night to relax and listen to some tunes or watch a flick.. appealing. I already have most of the equipment to do it, would just need a few more odds and ends, cabling, and of course.. the speakers.

[norman bates]

nope, I'd never tolerate a large setup, except mine, lol.

You can watch / listen to Tron Legacy movie / soundtrack at "11".

Norman

[Loren42]

The woofers you cited do not play very deep for HiFi use.

The system you propose might lend well for sound reinforcement activities, but I would be surprised if you could cobble together a 2-Way with an 18" woofer and get effective results for good HiFi listening.

I am experimenting with a 15" Acoustic Elegance TD-15H and a Beyma TPL-150 for a two way. Cabinets are about 50% completed and I might get them done today.

However, I think I am pushing the limit with the 15" and worried that the result will be less than hoped. I would not expect very good results with an 18" due to the larger cone surface and directivity issues at such a high crossover point for an 18.

[norman bates]

I wouldn't cross that goldwood horn below 1khz (due to the mouth size). And wrap the mouth in foam, it will sound better.



It's hard to find an 18" that goes that high to catch the horn crossed at 1khz also. Like pinkmouse said, it's a job easier for a 15" (but harder to find one looking at freq. graphs nowadays).

A decade is a common range for horns (500-5khz), but people break that rule often, especially that 2-way with 18" or even the 8" full range drivers front horn loaded crossed at 200hz. Dispersion gets to be a big preblem with non cd-horns as you go up in frequency.

And getting a 2" up past 8khz, you can be asking for trouble. Most diaphrams are in pure breakup mode up there, they masage cone resonances and play with phase plugs to get a reasonable / flatish response.

And you still may want a subwoofer (for the .1 low freq effects from dolby digital / dts). Movies just arn't the same. I know I miss the lfe at times, but may fix that in the future. But I like the bass slam from a big 2-way and bass integration compared to 3-ways.

Norman

[Charles Darwin]

I'd consider twin 15"s rather than a single 18".

[DrDyna]

Originally Posted by norman bates

nope, I'd never tolerate a large setup, except mine, lol.

You can watch / listen to Tron Legacy movie / soundtrack at "11".

Norman

Or Judge Judy yelling "I'm Speaking!" @ 120db.

[el`Ol]

Originally Posted by BHTX

Where to get a massive waveguide like that? Cost? I'm aware of the Le Cléac’h Azurahorns, if that's what it is.

They are not Azuras. I think they are custom-made for the Lautsprecher-Shop.
Lautsprechershop