Cone driven mid-range for a Khorn

[oscarsear]

In my on going education about upgrading the mid-range for my Khorns it has been advised by some none Klipsch owners that a cone driven mid range tractix horn would be a better option than a compression driven mid-range tractix horn. The premise given is that there are cone drivers that can easily meet the lowest and highest end of the mid-range crossover frequencies used for the Khorn (as a 3rd order crossover). Cone products such as the Fane 8M and the Supravox 285-2000 are 8 inch drivers that have been mentioned in this context. To get these bigger boys into a tractix design they get into bigger boxes or damn big spherical horns.

Read other forum posts that suggest that compression drivers give more detail...is this so? There are very few compression drivers that perform well under 500Hz and my AK-4 cuts at 450Hz and ALK's ES cuts at 400Hz so why not go to a cone (size notwithstanding). The Khorn bass is a cone driven horn. Should the mid-range be one also?????

[3dzapper]

Scroll down to "The Edgar Midrange Horn".

http://www.volvotreter.de/dl-section.htm

In this article, Dr Edgar experimented with a group of cone drivers with a tracix horn.

Rick

[Marvel]

John Warren also used two JBL 10" drivers for mids on each of his KHorns.

I was looking at a B&C 6PEV13 (a 6.5") to put in a tractrix, but

I've never gotten around to doing it. Dennis had also suggested their

8PE21 (an 8").

Bruce

[homemade]

I have an Audax PRM17 6.5inch (model number something like this) without the horn. You will probably find a less "horn" sound by eliminating the horn altogther. These run about 99.6 db efficient and if you get a 4ohm version you would be in the ballpark efficiency wise. I cross mine over at 400hz with a 12db crossover. Have run it with 200 watt amps without any problems but don't expect 120db for extended periods either.

[djk]

Cone driven midrange horns largely aren't (horn loaded).

The Edgar horn with the JBL LE5-2 is a good case in point. The throat was pretty big, so there wasn't much of a compression ratio. It had some big peaks in the low end (of the midrange) where the horn loading was more effective. It smoothed them out by destroying the horn loading, providing a big leak at the throat (a 'gasket' made out of a Scotchbrite pad).

Large cone driven horns like the Oris and the Azura loose their horn loading above 1Khz as the drivers start beaming (due to the large throat size and no phase plug) and the sound waves don't even touch the side walls of the horn.

Community Light and Sound (CLS) made a large cone driven mid horn without a phase plug (RS440) that sounded quite good. It had a 2:1 compression ratio, used the above mentioned Audax PR17 driver, and was crossed at 400hz and 1.2Khz (to a 1" aluminum compression driver).

The Audax PR17 was not made in 4 ohms, but the T2A autoformer may be used as a step-up device. The newer Audax don't perform as well as the older ones, but this is moot, as they will no longer available. B&C makes a clone of the older (IMO better) version. The horn really helps out these type of cone mids as they really are only 99+ dB above 2Khz, and smoothly slope down about 6dB by 200hz or so (94dB). With a 2:1 throat we pick up 3dB from compression, and about 6dB from directivity in the 400hz region, bringing it up to around 103dB. Due to the mass corner of the driver, and the beaming of the cone, the horn doesn't do much (if anything) above 2Khz (like the Oris/Azura).

JBL makes cone driven horns with 10"/8"/4.5" drivers, all with phase plugs (but relatively low compression rates) that may be used to 1Khz/2Khz/4Khz, but these are beyond most home constructors (because of the phase plugs) and the 8"/4.5" drivers are not available as a catalog item.

[DrWho]

The Mackie SR 1530 (http://www.mackie.com/products/sr1530/index.html) uses a hornloaded midrange driver and its one of the better sounding small venue PA speakers I've heard. I'm not suggesting you try implementing this particular design, but it certainly doesn't sound as bad as some other alternatives out there.

[homemade]

Here's a freq. plot with my homemade khorns with the Audax 6.5inch midrange, T-35 EV treble horn and Eminence 15inch woofer (8 ohm) and 12inch subwoofer. This freq. response is with 10band 1 octave noise and Radio Shack meter (uncalibrated).

32.5hz +1db
63hz +5db
125hz +8db
250 +3db
500 -1db
1k 0db
2k -1db
4k +1db
8k +3db
16k -8db

As you can see, the midrange has a very flat response (from 500hz to 4k). The peak in the 125hz range is part speaker and part room (I had the meter sitting on an arm of a loveseat that was against the back wall). The midrange could stand to have a couple more db output but it might sound too bright.