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Cornscala horn question


mopardave
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Since building my Cornscala's which were a Cornwall conversion I'm not liking  them much.  They sound way laid back compared to the 600 in your face mid horn.  Have any of you using the large mid horns noticed this with the Cornscala?  Using the zxpc horn with a B&C85. Seems like i have to turn the volume up much further than my Cornwalls or Super Heresy require. Not near as efficient as a typical Klipsch Heritage. Not sure if this is typical of the large mid horn or not.  Other thing is using a ALK CSW cross over adjusted  to my liking, but still laid back.    Maybe the cross over is the culprit or the DE85?

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7 hours ago, Honeybadger said:

What is a  zxpc horn?

 

Don't think its the crossover, used it many times, always liked it.

 

HB

The zxpc horn is a 11x7 open horn.    I don't know, but maybe the drivers are just not as efficient as what's used in the Heritage line.    A 1/4 turn on the volume knob was all it took to hit 100db levels with the Cornwalls.  The Cornscala's at 1/4 turn are at 75db output.   

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Do you have the original crossovers? If so, may want to reinstall them as a test.

 

The woofer typically dictates the speakers efficiency.  If the oem woofers have been re-used, it is unlikely the efficiency has changed.

 

The issue may be a mis-built crossover, though I have never had one from ALK.

 

HB

 

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18 hours ago, Honeybadger said:

Do you have the original crossovers? If so, may want to reinstall them as a test.

 

The woofer typically dictates the speakers efficiency.  If the oem woofers have been re-used, it is unlikely the efficiency has changed.

 

The issue may be a mis-built crossover, though I have never had one from ALK.

 

HB

 

I do not have the original xover as they were used in my super heresy.  I have suspected the woofers as well, but they do test 4ohm.   I got a good deal on these 3015lf woofers thru avatar speaker, but they arrived with no decal labels identifying them at all.  I am suspicious of this.   May have to buy another set of woofers.  The tweet is a B&C DE120. Thanks

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The driver has a 107db sensitivity so it is not the problem. It is possible that it is not a good match with that horn. A possibility but I doubt that is the problem.  I would look at the crossover as the problem. Without attenuation on the horn driver combination it should hurt your ears with just a touch of the volume control. Way louder than the bass speaker. Very few bass speakers reach 100db sensitivity. Most far less. Attenuation is the problem. If you cannot design a crossover yourself give Bob Crites a call. I bet he can solve your problem. I am not familiar with the crossover you have but if the attenuation is adjustable you do not have it set correctly for your setup. 

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3015 LF is an 8 ohm driver, DCR is 5.5 ohms.  A quick look at the specs shows, the 3015 is not a good match for your Cornwall cabs.

 

With no labeling, I am suspect also. The Eminence 15c is very close to the original K-33 and is a suitable replacement.

 

I would consider replacing the woofer with an Eminence 15c or one from Bob Crites. 

 

Again I doubt the crossover is the issue, the circuit is fairly simple. If you can post a pic of the crossover, might be able to spot a flaw.

 

HB

 

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I’m using the 3015lf_4 crossed at 500, and the zxpc 18x10 horn with a Faital ProHF146 with -12db attenuation courtesy of a 3636 autoformer with 1.2uf In front of the AF and 3.0mh in parallel with the driver. I get all the in-your-face mid presentation of my CWIIs only much more refined. I believe the speaks that avatar was selling were 4 ohms, going from memory.  I’ve not used that compression driver before but you could experiment with an lpad and see if it’s a level thing.  

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13 hours ago, mopardave said:

I do not have the original xover as they were used in my super heresy.  I have suspected the woofers as well, but they do test 4ohm.   I got a good deal on these 3015lf woofers thru avatar speaker, but they arrived with no decal labels identifying them at all.  I am suspicious of this.   May have to buy another set of woofers.  The tweet is a B&C DE120. Thanks

do you still have the older woofers ---

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2 hours ago, jwgorman said:

Can you tell how much attenuation is on the B&C with your crossover? And what is the value of the cap on the mid circuit? 
I’m not familiar with that crossover. 

I have the mid attenuated at 11 and the 120 at 6. I believe the cap is 33 400v.  according to B&C web site the DE85 is 108db and 8ohm.

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8 hours ago, mopardave said:

I no longer have the K33e's and yes is does sound like the polarity is reversed.  I did check the polarity on everything and it checks ok.  I did not try switching polarity.

Have you made sure that the ohm rating on the new drivers is the same as the stock drivers?

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