2 inch compression drivers
Here is a link to P.Audio re 750, in australia this sells for aprox A$230 A$=us77c an affordable choice. complete with graph.BM 750
top of the range is the PA D99, sounds extremely similar to JBL 2446 (without the price tag) [url]http://www.paacoustic.com/pdf/P-SERIES/P10-100MB-PA-D99.pdf[/URL]
note how flat the response is to 8k
Here is a link to P.Audio re 750, in australia this sells for aprox A$230 A$=us77c an affordable choice. complete with graph.BM 750
top of the range is the PA D99, sounds extremely similar to JBL 2446 (without the price tag) [url]http://www.paacoustic.com/pdf/P-SERIES/P10-100MB-PA-D99.pdf[/URL]
note how flat the response is to 8k
AndrewT said:
(Hmm, should I stick my neck out on this one or not? ...lot of opinions on this subject.)
What the heck, here goes.
I'm not a speaker designer and most of my understanding on horns ("the curvy bit in front") not scientific but from my experience and readings.
A horn is an "Acoustic Transformer". It's job primary it to match the high pressure loading presented by the compression driver to the atmospheric pressure at the mouth of the horn. The "quality" of the horn would depend on how well it provides:
- accuracy of reproduction (translate the acoustic signal from the throat to the listener with low THD and IM. Will depend in large prt on the driver used)
- wide BW (will depend in part on the driver used and in part on the horn design)
- well controlled dispersion across it's BW (depends entirely on horn design)
- smooth spherical expansion of the wave front (depends on horn design)
- linear power response (low level and high level signals reproduced in the correct proportions. Will depend in large part on the driver used)
- and it is made free of mechanical resonances
If you can find or make a horn to meet all of these criteria, you'll have, IMHO, a high quality horn.
One of the ways that the pro sound crowd (i.e., horn folks) get around the 4 octave problem is to design mid and high frequency drivers with a rising response curve to make up for the inevitable unloading of the horn. Along with their limited x-max, this rising response limits their wide band use in other non-horn designs...unless heavy EQ'ing is applied.
550 Hz - 13 Khz
I use TAD 4002 drivers in Bentwood 200Hz horns and cross them at 550Hz. They are equalized to be flat from 550 - 13 KHz. I also have supertweeters crossed at 13KHz, but they add very little - there is very little program material above 13 KHz. In any event, I'm over 40 and can't hear much above 16 Khz. I will probably ditch the supertweeters soon.
The TADs with JBL 2226Hs below 500 Hz are outstanding and I recommend them highly.
I use TAD 4002 drivers in Bentwood 200Hz horns and cross them at 550Hz. They are equalized to be flat from 550 - 13 KHz. I also have supertweeters crossed at 13KHz, but they add very little - there is very little program material above 13 KHz. In any event, I'm over 40 and can't hear much above 16 Khz. I will probably ditch the supertweeters soon.
The TADs with JBL 2226Hs below 500 Hz are outstanding and I recommend them highly.
Attachments
I'm not at home, so this is a guesstimate, not a measurement. The horn mouth is around 36" x 18". The whole speaker setup is thus about 4 and 1/2 feet tall - bigger than the picture suggests. It's triamped using brutefir for xo and driver/room correction.
I have a wonderful and very tolerant wife.
I have a wonderful and very tolerant wife.
Ok, I did not have time to read the whole thread... but...
You're not going to get a horn in most cases to be "sucessful" if you try to run it out to 20kHz.
Two big problems, if you get it out that high, it will have to be hyper beamy due to the requirements of the throat area... The second problem is that the throat area itself, for any sort of good dispersion will have a geometry that isn't good as you go higher in freq.
The possible exception to this might be the newer "waveguide" type of expansions from Geddes and Peavey - but they do require new style compression drivers with short short throat areas to work properly at higher HF freqs...
The various diffraction "lenses" are not entirely sucessful with making the HF dispersion wider - usually they don't sound good. The JBL "potato masher" maybe comes closest to being ok. Again, imho.
Imho, the goal is best to cover from <300Hz up > 10kHz+ .
This puts ur critical vocal elements from one single source, and will sound way better than splitting the voice at 500 - 1000 Hz. Imho, of course.
Another factor is that the 1.4" exit (Altec) and the 2.0" (JBL) compression drivers because of that dimension tend to not do well above ~14khz or so... the smaller exit 1" drivers do better, but won't go lower... I pick the ones that go lower over the ones that go higher in my system, although I'm using some unique compression drivers that are at ease down at 250Hz.
Btw, take a look at the WE555's specs, they work down to an amazing 75Hz.!
I don't see any of the so called "full range" cone drivers being acceptable or even getting out to 20kHz. anyway, so I kinda write them off the list for horn loading.
Oh, fwiw, in principle all drivers intended for "horn loading" afaik have a so-called "rising response"...
_-_-bear
Ps. just read the first page... my horns are currently 300Hz. Altecs. I use 803, 1003 and 203. The 203 is the best of the lot imho. Don't have an 1803 I have found that MOST of the compression drivers out there are either A) unable to work below 400-500Hz properly, and/or B) are very very non-flat in response in general, but especially if you go below that 750Hz. area... (see Altec 288 response curves). The drivers I use are both able to go below that center point, and measure scary flat to boot - my xover is a single 20ufd. polyprop cap, nothing else. They're very clean and have monster "jump factor". I also play electric music live plugged into a mix board through the system, no problem - the average level is in the high 90dBs, peaks up substantially above 100dB. Clean.
The key to horns is[/ the driver!
The drivers I use now completely changed my mind about horns in general, because prior to finding these, it turns out I was hearing the deficits in the drivers not in the horns!!
Anyhow, the key in understanding where the difference is found is to discover what the difference is between the classic WE555 design is and the later WE design with the annular slitted phase plug (which is all subsequent designs...). Shhhh... don't tell anyone.
You're not going to get a horn in most cases to be "sucessful" if you try to run it out to 20kHz.
Two big problems, if you get it out that high, it will have to be hyper beamy due to the requirements of the throat area... The second problem is that the throat area itself, for any sort of good dispersion will have a geometry that isn't good as you go higher in freq.
The possible exception to this might be the newer "waveguide" type of expansions from Geddes and Peavey - but they do require new style compression drivers with short short throat areas to work properly at higher HF freqs...
The various diffraction "lenses" are not entirely sucessful with making the HF dispersion wider - usually they don't sound good. The JBL "potato masher" maybe comes closest to being ok. Again, imho.
Imho, the goal is best to cover from <300Hz up > 10kHz+ .
This puts ur critical vocal elements from one single source, and will sound way better than splitting the voice at 500 - 1000 Hz. Imho, of course.
Another factor is that the 1.4" exit (Altec) and the 2.0" (JBL) compression drivers because of that dimension tend to not do well above ~14khz or so... the smaller exit 1" drivers do better, but won't go lower... I pick the ones that go lower over the ones that go higher in my system, although I'm using some unique compression drivers that are at ease down at 250Hz.
Btw, take a look at the WE555's specs, they work down to an amazing 75Hz.!
I don't see any of the so called "full range" cone drivers being acceptable or even getting out to 20kHz. anyway, so I kinda write them off the list for horn loading.
Oh, fwiw, in principle all drivers intended for "horn loading" afaik have a so-called "rising response"...
_-_-bear
Ps. just read the first page... my horns are currently 300Hz. Altecs. I use 803, 1003 and 203. The 203 is the best of the lot imho. Don't have an 1803
I have found that MOST of the compression drivers out there are either A) unable to work below 400-500Hz properly, and/or B) are very very non-flat in response in general, but especially if you go below that 750Hz. area... (see Altec 288 response curves). The drivers I use are both able to go below that center point, and measure scary flat to boot - my xover is a single 20ufd. polyprop cap, nothing else. They're very clean and have monster "jump factor". I also play electric music live plugged into a mix board through the system, no problem - the average level is in the high 90dBs, peaks up substantially above 100dB. Clean.The key to horns is[/ the driver!
The drivers I use now completely changed my mind about horns in general, because prior to finding these, it turns out I was hearing the deficits in the drivers not in the horns!!
Anyhow, the key in understanding where the difference is found is to discover what the difference is between the classic WE555 design is and the later WE design with the annular slitted phase plug (which is all subsequent designs...). Shhhh... don't tell anyone.
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