Distincition Between Various Electrovoice Tweeter Horns?

[Northeastern Illinois]

Good morning,

Many of us are familiar with the Electro-Voice T35 (round Alnico magnet), T35A (square ceramic magnet), and T350 (round Alnico magnet . . . don't know if there was ever a T350A though).

I have recently seen reference to an Electro-Voice ST 350A (ceramic magnet) and ST 350B (square ceramic magnet). Both are described as having the "baby cheeks" flare. Does anyone have specifications, literature, etc. on these components? What does the "baby cheeks" flare mean? Are they later members of the T35 et.al. family? Can they be used as substitutes if one cannot locate a T35 or T350?

[TBrennan]

The ST-350 was the last version of the T-35 family of tweeters, all of which shared a common diaphragm but with varying motors and horns. The ST-350 uses a "buttcheek" constant-directivity horn that gives a very wide and stable dispersion pattern, 120 degrees horizontal was claimed. Because of the horn's constant-directivity design frequency response on axis tracks the driver's power response and this horn works best with EQ. Somewhere I have info from EV on the EQ to be used with the horn. The ST-350 used both Alnico and ceramic magnets and was used in the Sentry III studio monitor and the Sentry IV 3-way horn utility speaker. Many consider this the best EV tweeter though another camp considers the T-350 the best.

This message has been edited by TBrennan on 07-16-2002 at 09:36 AM

[WMcD]

If Northeastearn (or anyone else interested) will send me a postal address by e-mail I can send some spec sheet info on the ST-350 and T-350 and T-35A.

The sheet on the ST-350 shows two equalizer/crossover circuits with lower limits of 3000 and 6000 Hz. Just as Tom says.

I think the term baby cheeks was a nickname for a JBL tweeter. It has the spheroid surfaces to either side of the driver openings. On the ST-350 they are above and below.

Also, my recall is that there was a member of the ST-350 series meant for flat mounting and thus had a planar mouth. Maybe that was the -A????

Gil

This message has been edited by William F. Gil McDermott on 07-16-2002 at 06:05 PM

[djk]

The ST350 is a 'pseudo' constant directivity horn, it has a narrowing in horizontal directivity and then broadens right before it cuts off in the low end. If you use it in a three way system you will never be able to tell, although both EV and BagEnd did use it in a 12" two way. The original ST350 had a large ring type ceramic magnet. Alnico was just too much money. When they came out with the strange square ceramic magnet T35 (by request of their largest OEM customer, Klipsch) they went to two stacked square magnets on the ST350B, one didn't have enough energy. There was a flat front true constant directivity version with a single square magnet, Speakerlab sold it as the WA4000 (Wave Aperture). It would be interesting to mount the stacked magnet structure from a ST350B on a K77 and see how much the high end would improve. The paper spacer ring beween the diaphragm and the top plate of the magnet on the ST350 is much thicker than the T35 (for excursion purposes). If it becomes damaged or lost while servicing, EV suggests using three T35 gaskets.

[Ray Wood]

I bought a utility model Klipschorn in the late 1950's. It had the T35 tweeter, which was said to responsive to 18K. When the T350 tweeter came out, I read that it was rated to 23k. I don't have any verification of that, but I always wondered if those stats were accurate, and if the Klipschorn ever used the T350. I have heard a lot of praise for the T350, even so far as calling it the best tweeter ever.  

[Travis In Austin]

5 minutes ago, Ray Wood said:

I bought a utility model Klipschorn in the late 1950's. It had the T35 tweeter, which was said to responsive to 18K. When the T350 tweeter came out, I read that it was rated to 23k. I don't have any verification of that, but I always wondered if those stats were accurate, and if the Klipschorn ever used the T350. I have heard a lot of praise for the T350, even so far as calling it the best tweeter ever.  

Welcome to the Forum.

[Travis In Austin]

5 minutes ago, Ray Wood said:

I bought a utility model Klipschorn in the late 1950's. It had the T35 tweeter, which was said to responsive to 18K. When the T350 tweeter came out, I read that it was rated to 23k. I don't have any verification of that, but I always wondered if those stats were accurate, and if the Klipschorn ever used the T350. I have heard a lot of praise for the T350, even so far as calling it the best tweeter ever.  

If you want the most accurate information on this I would suggest you post this excellent question in the Klipsch Museum Section, in the Subsection Ask the Historian and Jim Hunter may be able to answer this question for you.

[Curious_George]

On 2/15/2022 at 11:29 PM, Ray Wood said:

I bought a utility model Klipschorn in the late 1950's. It had the T35 tweeter, which was said to responsive to 18K. When the T350 tweeter came out, I read that it was rated to 23k. I don't have any verification of that, but I always wondered if those stats were accurate, and if the Klipschorn ever used the T350. I have heard a lot of praise for the T350, even so far as calling it the best tweeter ever.  

 

The data for the T350 is accurate IF you find a T350 with a good phenolic diaphragm. The T35 and T350 used the same diaphragm and it was common knowledge that the K77 was a cherry picked T35. The same would apply to the T350 as well. The larger motor structure was responsible for extending the high end past 20kHz.  

[boom3]

EV Avedon T35.pdf

[OO1]

On 2/15/2022 at 11:29 PM, Ray Wood said:

 I always wondered if those stats were accurate, and if the Klipschorn ever used the T350

I still think it is the BEST tweeter ever , I own several pairs of the T350  , it's a very high quality tweeter with  an Alnico V 1 lbs magnet versus 4 oz  / 6.8  and 7 ounces on the various versions of the EV T-35 ,  the K-77 were selected by Klipsch by pairs for matching DCR  values  , but klipsch never used the T-350  as it was very expensive  .

 

The EV T-35   and EV-T350  were available in 8-16 Ohms versions .

The Ferrite magnet Version of the EV-T35 extended lower than the Alnico V magnet  T-35 , The EV-T350 was only Alnico V   .

The EV T-35/T-350  diaphragms  varied in quality , with the higher durability units featuring  Beryllium leads .

 

Specs :

 

EV T-35     16 Ohms      3.5Hz /19KHz                    Alnico V

EV T-35B   16 Ohms      3.5Hz /18KHz                    Alnico V

EV T-35      8  Ohms      3.5Hz /20KHz                   Alnico V

EV T-35A    8 Ohms      3.5Hz /15KHz  - 16KHz     Ferrite

EV T-350   16 Ohms     3.5Hz  /21KHz                    Alnico V

EV T-350    8  Ohms    3.5Hz  /23KHz                    Alnico V

 

https://products.electrovoice.com/binary/T350 EDS.pdf

https://www.cieri.net/Documenti/Istruzioni/Electrovoice - Tweeter T35, T35B, T350.pdf

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