Stargate 6 Horn System

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POOH

POOH

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Joined 2010
JoshK said:
The one gripe about the phase plug and resultant upper extension is the lack of attention to polar matching at the crossover region. The higher you push the horn's pass band the more narrow the directivity. Problem as I see it, the next horn will have its widest directivity at the lower portion of its passband, so where you are intending to cross you have a big mismatch in directivity. The crossover is fine on-axis, but what we hear is so much more than the on-axis that the spectral distribution in room is off.

It might seem academic, but I think that horns should be used over a conservatively chosen passband, so phase plugs in this case are not your friend. If I were to pick up these drivers to experiment in my horns, I'd still test out the phase plugs, but more than likely I'd abandon them in the complete system.

In this regards, I wholly agree with Romy and other astute horn aficionado's that designing horns is more about how it fits together in a complete system rather than making the best stand alone single horn.
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Actually what happens with the phase plug is the opposite what you say. The phase plug allows for a much broader pattern at the top band of the horn then without it. That's one of the main problems I have with just placing a cone in a midhorn and expecting it to work. It doesn't have the power response to match the next upper range horn. The phase plug is definitely my friend ;)

To abandon phase plugs in your system means you no longer use compression drivers. The CMCD is exactly that a compression driver that was built to outperform all others in a specific range. In this case probably the most important decade.
 
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POOH

POOH

Member
Joined 2010
Another problem with narrow directivety in mid horns is their length. For example the big midrange horn you have. If you shorten the mouth by a foot or so there will be a lot less beaming at the top at the expense the low cutoff loading. You can also integrate it with the other horns better because it's no t over sized with that big lip. The horns in this system are segmented so I can add the mouth back or remove because I have made several pieces to experiment with and as well as use it with several different throat sizes ranging from 1" to 6". I have found the shortened horn actually sounds better with the 4" throat then the full mouth tractrix. Your mileage may vary so does mine depending upon my configuration and goal
 
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J

JoshK

Member
Joined 2004
POOH said:
Actually what happens with the phase plug is the opposite what you say. The phase plug allows for a much broader pattern at the top band of the horn then without it. That's one of the main problems I have with just placing a cone in a midhorn and expecting it to work. It doesn't have the power response to match the next upper range horn. The phase plug is definitely my friend ;)

To abandon phase plugs in your system means you no longer use compression drivers. The CMCD is exactly that a compression driver that was built to outperform all others in a specific range. In this case probably the most important decade.
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Were you able to measure that? Seems counter-intuitive to me.
 
POOH

POOH

Member
Joined 2010
This particular compression driver allows for the phase plug to be removed and used without it. When I did that I did measure a big difference in the upper range response on and off axis. It also had the inferior sound of the many cones I tried in the midrange horns without the phase plug. The phase plug's purpose is to give you a more extended broad range response be it in this driver or any other that use phase plugs. If you were to remove the phase plug from your treble compression driver it's performance would probably make it nearly un-usable.

http://www.fohonline.com/current-is...standing-compression-drivers-phase-plugs.html
 
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W

winslow

Member
Joined 2005
Bummer...was trying to figure out the pedigree of those horns. All I've heard over the years was they were designed by a fellow that had something to do with Klipsch horns. And yours were the only thing that I've ever found that was remotely connected and remotely similar.
 
POOH

POOH

Member
Joined 2010
A 340S P.Audio System Co., LTD

I'm now going between the TAD 2001 and the Celestion 1747 2k up in the Faital treble horn - probably will stick with the Celestion - it sounds a bit less hyped and more natural to me

The P Audio drivers are really good for the money if you use them for live PA - never sound compressed, nice middle range but the ones I have fail the treble test with nasty upper treble spittyness and resonance - these were left over from a big modular horn loaded line array system I built for a local band :)
 
POOH

POOH

Member
Joined 2010
If you are going to horn load them and want much better upper range response and better power response you also need the phase plug. Order the CMCD-82H through an authorized JBL repair center. I believe they are around 690 dollars. I've been trying to get more drivers and some horns from the guy i got mine from but he's been to busy to put them on a bus and ship them to me. It looks like it may require a road trip but I'm not sure if he is reliable enough to be there when I get there :confused:

The driver in a horn is around 108 db sensitive throughout it's bandwith
 
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JoshK

Member
Joined 2004
POOH said:
The JBL CMCD81H I have has nearly perfect response in my shortened 180 Hz horns 300-2.2K - above that it does exhibit some break up and should not be used . I use a narrow band trap filter on mine and crossover electronically. To compare to other cones I have used in the same horns (probably 20 of them) they are far superior in being linear, putting out the energy in the upper range and just overall sounding real. I have never heard midrange from a speaker to equal this regardless of it being horn, ribbon, electrostatic or planar. It is that good. I have not used the Faital driver you have.
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Hey man,

Do you have any more details about your shortened 180hz horns? I'd like to see what you did. I have a pair of these drivers (and phase plugs) to experiment with.
 
L

LZ1KEZ

Member
Joined 2015
cmcd 81h vs. cmcd 82h? Enclosures?

POOH said:
If you are going to horn load them and want much better upper range response and better power response you also need the phase plug. Order the CMCD-82H through an authorized JBL repair center. I believe they are around 690 dollars. I've been trying to get more drivers and some horns from the guy i got mine from but he's been to busy to put them on a bus and ship them to me. It looks like it may require a road trip but I'm not sure if he is reliable enough to be there when I get there :confused:

The driver in a horn is around 108 db sensitive throughout it's bandwith
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Hi POOH/everyone,

I was wondering where any of you did experiment with both cmcd 81h vs. cmcd 82h? Any improvements on behalf of cmcd 82h and in what kind of enclosures - tractrix or PT recommended wavegudes? Seen that the sensitivity in cmcd 82h has been imoproved (varieble? - 110-112? dB SPL, 2.83V (1W) @ 1m (3.3 ft) and magnet system changed. Was curious to know how it happened in real life - infortunately not able to test/compare both drivesrs at present. While cmcd81h can go down as low as 250Hz, how about cmcd82h? Many thanks.
 
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