Horn from 500hz to 20khz, how hard?

[bigwill]

I was wondering how hard it would be to build a horn that covered the range from 500hz all the way up to 20khz with a reasonably smooth response. I don't have any definite plans but I was wondering if it was possible with standard compression drivers and larger than average horns. It would be nice to achieve such a thing because most of the critical range would be covered by a single high efficiency low distortion source. The distortion might be on the order of ESLs with the advantage of higher efficiency and an easier load for amplifers. It would also invite experimentation with lower powered amps.

[roddyama]

The closest I've heard so far is the TAD 4001 and with it flat response would questionable below 1000Hz and above 16kHz or so. Of course the horn used would also make a difference. I haven't heard any of the real high end stuff like the Goto's.

[Cal Weldon]

Hi bigwill,

Lots of horns have no trouble with 500, it's the driver that's tough to find. I don't know of any that will give you 500 - 20K. You may have to think about a super tweeter. Besides you're talking about something they used to do in the 50's and 60's. The old Altec stuff was XO'd at 500 but the top end was limited to around 15K, which IMHO is enough anyway. I don't know anyone that can hear 20K.

There were no high powered amps back then so they had to use horns. Once the bigger amps came out, horns kind of went by the wayside in favour of smaller cabinets.

[roddyama]

Originally posted by Cal Weldon
...Once the bigger amps came out, horns kind of went by the wayside in favour of smaller cabinets.

Well, most of the horns anyway (I've seen the pictures of your speakers Cal ).

[Cal Weldon]

Guilty as charged! I guess I'm just an old fashioned kind of guy

[dwk123]

I'm not an expert, but you might have to look at 'unconventional' approaches to hit the goals. Specifically either a Unity arrangement, or else something like the BMS coax drivers (4592).

I have a pair of Unities (U15's), and they do 300 to "20k" (probably only 18.5k) from the horn. The mids handle the first ~2 octaves of that. This pretty much requires buying a commercial speaker, though - none of the DIY attempts (including mine) seem to have ever made it to production quality.

The BMS should be OK down to 500 if it's for home use, although I'm not sure what horn would support that. 18Sound has one that looks good, but I haven't seen any concrete feedback from someone that has tried the combo.

[Cameron Glendin]

A great 2 inch driver with a large flare can cover the 500 - 7k region smoothly and with a very flat response. This is the basis of most cinema systems and then the response then drops. JBL designed a crossover that reduces this band so that the higher frequencies are boosted, extended the top end results. To me it sounds very good.

The ideal way in my opinion is to use a super tweeter for the higher frequencies above 7k .

I have used many 2 inch compression horns over the years JBL 2446, EV Dh1, P.Audio D99 and BM750, Altec 288 (1.4 inch). I find that the results are equally impressive.

A quality 1" driver such as P. Audio PA D45 would be smooth up to 10 k and could be crossed over at 500 although I would probably start at 800hz.

I personally like the sound of quality cinema speakers and find the drop of of the extreme top end does not worry me. eq could extend the response to 16k. Perhaps try and add a super tweeter if neccesary.

For a great sounding response from 500hz the biggest and deepest flare you can get will give the most impressive results.

There are good reasons not to xo in the middle of our hearings most sensitive region, 500hz crossovers do have an advantage in this aspect.

[Pano]

I agree with Cameron and Cal. It can be done, has been done- and done well. The driver is the trickey part.

I also don't care much that these horns tend to roll off at 15-16K. That's enough for me. Even in my youth I didn't like super tweeters. Even if they sound nice, they don't sound natural. Always too "Hi-Fi" for my tastes.

Let us know what you find. You could always start out with the classic Altec 511 horn and a nice dirver. Once you have those, see if you can build a better horn.

[planet10]

Typically a horn is limited to a bandwidth of ~4 octaves

dave

[jzagaja]

Why not to use an ordinary cone driver to cover 300-20000 range? The freq. transmittance is very bad but if you put a phase plug the things may improve isn't it? Example of Jordan JXR6 in 400Hz Tractrix appended.