La Scalas and Crites CT120 tweeters, possible?

[laemmle]

Hello,

I am swapping my Crites 125s for 120s and I can't figure out how to install them. The 125s had the horn that you can unscrew from the driver but the 120s seem to have the thread of the horn glued to a circular plate that unbolts from the driver but won't fit through the tweeter port. Is it possible to install them?

Thank you.

 

edit: I should have mentioned I have the horns front mounted through the tweeter port with the driver on the inside. I preferred the sound with the 125s.

Edited May 25, 2021 by laemmle
clarification

[KT88]

I can't give an answer that relates to the mechanics of the installation. But I would like to ask a basic question. Let's start from the original. The T35 /K77 horn was mounted from behind the baffle. Many years later it was mounted on the baffle from the front. Now there are alternatives like the CT125 and more recently the CT120. What were the considerations to design the horn of the CT125? I have Ct125, the horn is much longer than the K77. The phase plug is different. I don't know why...whether it was optimized for mounting from the rear, or sounds better mounted from the front?

According to the design, the CT125 is also intended to be mounted on the baffle from the rear. I don't know the intention of the CT120, but isn't it that it is the same horn with a different driver...even if the connection between driver and horn is designed differently?

 

Now back to the original horn. Just two days ago I wrote in another thread that the T35/K77 horn was designed as a diffraction horn. That means it should be mounted from behind the baffle and the travel way through the baffle has an intended function of the horn. But it should be vertically aligned according to the manufacturer EV. Only then it has a wider dispersion angle in the horizontal.

I don't know if the same effect is true for the CT125/CT120.
Regardless, many people here on the forum have spoken positively about the CT120, I haven't heard it yet, but like to believe it. Whether it sounds better when mounted from the front (horizontally) than when mounted from the rear is something you have to try.

 

Something else.  I think that the new K771 is a completely new approach. This horn has been designed from the ground up for horizontal installation. And it is designed to bridge the gap between old and new in such a way that it harmonizes perfectly with the K401.

[DeanG Crossovers]

Earlier models had a smaller cut out than later models, where you could add z-brackets which allowed for flush mounting. With the smaller cutout and that particular assembly, you have to mount to back of the motorboard and just deal with it. Or, you could buy a set of these: https://www.ebay.com/itm/Klipsch-K-77-EV-T-35-SMAHL-V2-Elliptical-Drop-In-Replacement-for-OEM-Tweeter-/223930007695?_trksid=p2349624.m46890.l49286

[KT88]

Unfortunately, I have not experienced this alternative yet, but it looks like it's optimized for horizontal orientation. Very interesting in any case. Question, will it fit from behind mounted on the baffle with the DE120 driver in the housing of the Lascala without that one has to grind mill and saw?

[KT88]

4 minutes ago, KT88 said:

 

 

[DeanG Crossovers]

Look at it carefully. It mounts from behind and rests flush with the motorboard. 
 

The K-77 works fine in the horizontal position. If it didn’t, they wouldn’t have used it that way for almost 75 years. 

[KT88]

I imagine what you say re the new horns Dean but will the Magnet of the driver, if it is a DE120, fit into the housing of the Lascala?

 

Yes, the K77 works fine since 75 years the way it is mounted in Klipsch speakers but regardless of that it was designed to be used in a vertical mounting configuration ideally. It does not mean it is not ok or „wrong“ to use it horizontally mounted. That is what they say themselves also.

https://mypicsonline.net/archive/archives.telex.com/archives/EV/Horns/EDS/T35A EDS.pdf

 

 

[OO1]

5 hours ago, laemmle said:

I preferred the sound with the 125s.

and some like myself prefer the K77 vs the APT 50 (125's )

[DeanG Crossovers]

24 minutes ago, KT88 said:

...but will the Magnet of the driver, if it is a DE120, fit into the housing of the Lascala?

Yes. It is a drop in replacement. 
 

I’m familiar with your document. Please keep in mind that we have accumulated a multitude of measurements on the K-77 over the years. 

[DeanG Crossovers]

 

[Dave A]

There is ample real world testing of the SMAHL here by forum users and plenty of info on Crites setup too. I have to admit you are the only one I have read of that wants to orient them vertically. My assumption is that if there was any real gain in doing this, it would be somewhat a common topic in the DIY crowd of which there are many here. I wonder if EV was referencing these in this particular pamphlet for long throw pro gear.

 

[Marvel]

The t35 was often paired with a midrange driver on an ev 8hd diffraction horn  also mounted both ways. 

 

Not a bad horn but the Fc is 600 hz. It's a 120h x 90v, if mounted the verticle orientation. Used a lot in EV designs.

[Marvel]

6 hours ago, KT88 said:

Now back to the original horn. Just two days ago I wrote in another thread that the T35/K77 horn was designed as a diffraction horn. That means it should be mounted from behind the baffle and the travel way through the baffle has an intended function of the horn.

 

There is slightly more diffraction when mounted behind the baffle, and they recommended routing the opening to a 1/4 inch thickness. Even if not on a baffle, it is still a diffraction horn.

 

A greater reason to mount on the back was you would have to take it apart and reassemble to front mount. Very difficult to do, as a member here did so and wrote of the difficulty he had.

[Dave A]

12 hours ago, KT88 said:

Question, will it fit from behind mounted on the baffle with the DE120 driver in the housing of the Lascala without that one has to grind mill and saw?

Yes. This is a direct drop in that is designed just for this restricted space where K-77's are traditionally used.

[jimjimbo]

1 hour ago, Dave A said:

Yes. This is a direct drop in that is designed just for this restricted space where K-77's are traditionally used.

And it is a terrific driver and horn lens combination… I have several.

[billybob]

Welcome to the forum!

@laemmle

[avguytx]

1 hour ago, jimjimbo said:

And it is a terrific driver and horn lens combination… I have several.

 

What is the main difference(s) you notice between the SMAHL lens and the stock CT120 sound quality wise? Some say the 120 is too laid back and the K77 has more "zip" to it. 

[jimjimbo]

I don't think the SMAHL/120 is "too laid back".....personally I think it is well balanced, especially in combination with the A55G mid.  I am not a fan of the "zip"....HF seems too bright and crackly....if that's a word.

[EMRR]

The mounting bolts for driver/horn are inaccessible unless the top panel is off the La Scala. You could mount while assembling a cabinet easily.  

[jimjimbo]

20 minutes ago, EMRR said:

The mounting bolts for driver/horn are inaccessible unless the top panel is off the La Scala. You could mount while assembling a cabinet easily.  

Don't understand what you are saying here?  Are you talking vintage LS, new LS, or?