Tweeter question for John Warren

[Guy Landau]

quote:

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Originally posted by John Warren:

Prior to 1995 the 8ohm EV T-35 was sold by MCM for $50 so multiple arrays where not that big of a cost. In series they are 16ohm (-3db). Doubling of area gives +3db for net effect of 0db (good) AND tweeter power capacity doubles. So use the simple 1st order network with tweeter pairs, get better highs and stop listening to all those resistors, chokes, capacitors, etc....

OR, just put the T-35 on the shelf and get a tweeter with *real* power handling capacity.

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John,

Which tweeter do you recommend?

Can an EV T350 be a direct replacement for the K77M in either 8 or 16 ohms variant in Khorns with type A crossovers?

Thanks

[John Warren]

JBL 2404 Bi-Radial 105 dB/W/m

Beyma CP25 104 dB/W/m

This message has been edited by John Warren on 07-25-2002 at 06:08 PM

[Guy Landau]

Thanks,John.

Did you try the EV T350?

[John Warren]

no.

2404H has better dispersion, clarity, with response to 21kHz. Replacement diaphragms are $90.

This message has been edited by John Warren on 07-26-2002 at 04:16 PM

[Guy Landau]

Thanks again,John.

I might be able to get the Beymas for 200$ a pair.

The fact that I can fit an EV T350 to the cabinet is more apealing but I might settle for the Beymas.

Did anyone ever replaced the K77-M with EV T350?

Thanks

[CaptnBob]

I was at one of PWK's seminars when someone asked him that very question. He replied that the T-350 didn't have as smooth a response as the T-35 when used in his speakers.

It should also be remembered the T-350 cost more than twice the T-35 - at least on my price list.

TC-35.....$26.25 (the Wolverine variant)

T-35......$33.13

K-77......$42.00

T-350.....$73.75

All prices circa 1963.

At the same seminar, someone asked him why he used screw terminals instead of 5-way binding posts. He said (and I quote here as best as I can remember) "The screw terminals make a more positive contact, but more important, it would cost me about a $1.35 more a cabinet to install them. When you sell about 200,000 loudspeakers, it begins to mount up!"

The T-350 is also about 4db more efficient, so you might have to pad it down a bit.

I guess the final analysis is, try the T-350 out and see if you like it. I doubt if you'll hurt anything.

Just to be on the safe side, I'd find out what problems the impedance differences might cause. You would'nt want to drop the crossover point much below 4K.

Capt'n Bob

[Guy Landau]

Thanks Capt'n Bob,

Is it possible to use 16ohm EV T350's?

How will it affect the sensitivity or crossover point?

Thanks

[John Warren]

in 1st order network, a change from 8 to 16 ohms at the tweeter means that the HF capacitor value has to be dropped 50% in value to maintain the same crossover point. An pad will need to be installed to since the T350 is brighter than T35.

[Guy Landau]

Sorry for all the questions,but how can I make the pad?

Thanks

[John Warren]

its time you get a book or two.

[Guy Landau]

Can you recommend any?

[Al Klappenberger]

Hi tweeter fans,

I took the plunge and bought a Beyma CP25 tweeter. I ran some crude curves

on it to compare it with the T-35 (K77) tweeter. The CP25 clearly has better

dispersion and goes higher. The curves are not done with the luxury of an

anechoic chamber, so they don't represent absolute frequency response. It's

just a crude comparison.

The red curves are the Beyma C25 and the black ones are the T-35. The bottom

curves were taken with the mike 30 degrees off axis. The upper pair are with

the mike on axis. The T-35 was in the vertical position though. Klipsch

mounts it the other way.

I expect to install the CP25 in my center Belle in the next few days for a

listen.

Al K.

This message has been edited by Al Klappenberger on 08-06-2002 at 04:00 PM

[John Warren]

it will sound better too.

[Al Klappenberger]

Hi tweeter fans,

I have mounted the single Beyma CP25 in my center Belle and

it sounds fine. I can't compare it to the T-35 until I get two more of them

mounted in my other two speakers though. They are on order, but Beyma is out

of stock on them right now (August 6, 2002). It's mounted inside the custom

grill frame I made. I don't see how the CP25 could be mounted in a stock

Belle or Khorn without major changes though. The horn is just too different

and requires an entirely different baffle cutout. It appears to be an

excellent replacement on a performance basis though, and at $60 each direct

from Beyma, they are a real bargain!

Al K.

This message has been edited by Al Klappenberger on 08-06-2002 at 05:31 PM

[John Warren]

the babycheeks should be mounted flush and

unobstructed (no grill cloth). I mount them on

seperate baffles atop the enclosure. Can be made to look good. Alternative it to build a new top section for the mid horn and new *improved* tweeter. This is straightforward for a Belle.

pack the cheeks with the usual damping materials such as modeling clay, rope caulk, sand-filled tar, aluminum oxide loaded epoxy, Glyptol,

polyester resin, monkey semen, etc....

This message has been edited by John Warren on 08-06-2002 at 06:56 PM

[killerbee_vr6]

Don't knock monkey semen.

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Gabe

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