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Bob Crites CT120 tweeters

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2 hours ago, Davedev07 said:

I added the Ct120 and the a/4500 crossover to my 70’s LaScalas, which had the original AL crossover..  It seems like the are overly harsh.  Very detailed, yes,  I read these crossover move the crossover point to 4500, and maybe that is part of the issue?  Any recommendations on what to try and tame them abit?  Thanks Davedev07

Yes, go back to AA

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Try the CT 120  with the AL --------instead of the a/4500-  

 

or try the CT 125  with the AL or the a/4500 - --nothing really compares to the K77-  but the CT 125 is the closest -

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I have had CT-120's, A-55-G's, and Crites A4500's in my La Scalas for quite some time and have been very happy with them. I haven't run a sweep on them yet, but I did recently run one on my Heresy's with the same 2 drivers as above. 

 

310496503_Heresy1SeatingPos.jpg.1145db159df824095649f60038d1c204.thumb.jpg.d96a8ac336eb2c73547e6f5eff97e998.jpg

 

 

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4 hours ago, Davedev07 said:

I added the Ct120 and the a/4500 crossover to my 70’s LaScalas, which had the original AL crossover..  It seems like the are overly harsh.  Very detailed, yes,  I read these crossover move the crossover point to 4500, and maybe that is part of the issue?  Any recommendations on what to try and tame them abit?  Thanks Davedev07

Hi @Davedev07

 

If you want to keep A4500, you can reduce the DE120 a bit by a few db with an Lpad, it will only cost you a handful of dollars for the resistors.

 

http://www.mh-audio.nl/Calculators/att.html

 

https://www.parts-express.com/search?order=pricelevel12:asc&keywords=dpr10

 

 

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I highly recommend what Mustang said. I do not think moving the crossover point has any bearing on what you are hearing. I would recommend these.  https://www.parts-express.com/L-Pad-15W-Mono-3-8-Shaft-8-Ohm-260-248  Easy peasy to install. Center pin goes to horn. If either one of the other pins hooked up wrong the L-pad will just be in reverse. Increase the wattage if you want but 15 watt is plenty good enough. Tweeter never sees a continuous 15 watts, doubtful even a peak 5 watts.  The driver for the horn is the culprit. Needs some attenuation to suit your taste. 

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All, thanks for the feedback.  The comment that the a/4500 can be attenuated?  How is that done?  I have not found any feedback on how that is done..

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Hi,

 

If you want to reduce your 8ohm tweeter by 2.8 db, use R1 = 2.2ohm and R2 = 22ohm

If you want to reduce your 8ohm tweeter by 2.2 db, use R1 = 1.8 ohm and R2 = 27ohm

...

 

https://www.electronics-tutorials.ws/attenuators/l-pad-attenuator.html

 

 

You have to put the R1 and R2 between the network and the tweeter

8PIWCCCPqC3uDT8Ze1VwWMI5ovK06cPBIeYUWf0C

 

 

 

 

 

If the resistance value R1 or R2 does not exist put 2 resistance in parallel to make the right value,

for example for a reduction of 3db, we have R1 = 5.6 + 3.9 = 2.3 and R2 = 33 + 47 = 19.4 (I rounded the values and results a bit, but it's ok)

 

2.3 (5.6 + 3.9) 19.4 (33 + 47) 8 3

 

 

list of values

R1 R2 impedance reduce db
2.8 (6.8 + 4.7) 15 8 3.7
2.8 (6.8 + 4.7) 16 (33+47+90) 8.1 3.7
2.8 (6.8 + 4.7) 17.1 (27+47) 8.2 3.6
2.5 (6.8 + 3.9) 17.1 (27+47) 8 3.3
2.4 (4.7 + 4.7) 18 8 3.1
2.3 (5.6 + 3.9) 19.4 (33 + 47) 8 3
2.2 22 8 2.8
2 (3.3 + 5.6) 24 (39+68) 8 2.5
1.8 27 8 2.2
1.7 (2.2+6.8) 31 (47+90) 8 2
1 (1.2+8.2) 56 8

1

 

😋

 

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5 hours ago, mustang_flht said:

If you want to reduce your 8ohm tweeter by 2.8 db, use R1 = 2.2ohm and R2 = 22ohm

If you want to reduce your 8ohm tweeter by 2.2 db, use R1 = 1.8 ohm and R2 = 27ohm

...

You have to put the R1 and R2 between the network and the tweeter

 

For reference:

59fcd8e18fa70_CritesA-4500top01-03-17.thumb.JPG.e20ef3a0cfce7ac5e43f8bd6f7af079d.JPG

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Hi,

 

I see that there is an autoformer on this network, if they have different sockets, it can perhaps be lowered by 2db without putting an Lpad. this is what you meant @wvu80 😎

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20 hours ago, Davedev07 said:

All, thanks for the feedback.  The comment that the a/4500 can be attenuated?  How is that done?  I have not found any feedback on how that is done..

Easy to do with L-pads from parts express.  Directions come with L-pad. You will need two, one for each channel. Just remember center pin goes to positive + of the driver. If you reverse the outside pins the L-pad will just work in reverse. 

 

 

https://www.parts-express.com/L-Pad-15W-Mono-3-8-Shaft-8-Ohm-260-248

 

260-248-parts-express-tech-drawing-40339

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3 hours ago, mustang_flht said:

Hi,

 

I see that there is an autoformer on this network, if they have different sockets, it can perhaps be lowered by 2db without putting an Lpad. this is what you meant @wvu80 😎

You cannot do that with the original Klipsch design crossovers without upsetting the crossover frequencies. ALK sells crossovers that can be done that way. 

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On 2/22/2021 at 5:59 AM, henry4841 said:

Easy to do with L-pads from parts express.  Directions come with L-pad. You will need two, one for each channel. Just remember center pin goes to positive + of the driver. If you reverse the outside pins the L-pad will just work in reverse. 

 

 

https://www.parts-express.com/L-Pad-15W-Mono-3-8-Shaft-8-Ohm-260-248

 

260-248-parts-express-tech-drawing-40339

I got the L pads, I’ll let you know how they work.  Thanks

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