Suitable Drivers for University Classic bass horn Cab

[fergs1]

Greetings peoples , I'm 3/4 way thru a University Classic front horn ( singular for mono) build so I'm committed to either the original University 15" driver(cost a fortune in postage) or its proven replacement (the EVM15L according to klipsch forum). I live in Australia and finding these units is proving to be very hard. If anyone can suggest an equivalent driver , esp one that is readily available and has a mass rollof up into the mid 400hz then I'd be most grateful. Below is the plans for the cab, the T&S for the EVM15L driver. Someone has suggested modelling drivers in Hornresp but I'm on Mac and quite frankly it is beyond my level of understanding. How would JBL2220A fare
cheers fergs
http://www.hifilit.com/hifilit/University/plans-1.jpgv

T&S for EVM15L Fs=43hz ,Vas=0.245m3 , Qts=0.238 , Qms=4.96, Qes=0.25

[fergs1]

Anyone out there?

[Inductor]

I'm probably of not very much help but some people are using the Eminence for subs/horns.
Eminence LAB 15
ELAB15 Eminence LAB 15 - 15" Subwoofer - die-cast Basket
Flightcase flightcases LD-Systems Cameo Eminence Palmer

[cyclotronguy]

I don't have specs for the original University driver.... back in the day when the University was current, they likely didn't publish Thiel Small. That said the pro drivers of that era were all kinda alike. I'm guessing the EV woofer is quite similar.

Cyclotronguy

[CLS]

How about making some sims for yourself?

Maybe it's a good chance to learn this wonderful tool.
Hornresp

[lowpoke]

Originally Posted by fergs1

... its proven replacement (the EVM15L according to klipsch forum). I live in Australia and finding these units is proving to be very hard.

Hi fergs,

A while back I was looking for a pair of EVM 15L drivers for some mid bass horns I'm building (design by Volvotreter). After much searching I finally found a guy called Michael from a company called TPac Sound and Light in Sydney. He had plenty in stock. He's definitely worth a try.

[Inductor]

Originally Posted by cyclotronguy

I don't have specs for the original University driver.... back in the day when the University was current, they likely didn't publish Thiel Small. That said the pro drivers of that era were all kinda alike. I'm guessing the EV woofer is quite similar.

Cyclotronguy

That's probably not a very broad scientific generalization if you don't mention the date. I understand you meant before the 70s.
1983 pdf EVM15L SeriesII driver
http://archives.telex.com/archives/E...20II%20EDS.pdf

A small "Speaker History Overview - Chapter 1 - 2 - 3 - 4 - 5"
Green Mountain Audio - Speaker-History-1948-1975
Thiele/Small - From Wikipedia, the free encyclopedia
Thiele/Small - Wikipedia, the free encyclopedia

[Inductor]

UNIVERSITY SOUND Speakers - Engineering Data Sheet - Product Data Archives
http://archives.telex.com/archives/U.../Speakers/EDS/
UNIVERSITY SOUND Drivers- Engineering Data Sheet - Product Data Archives
http://archives.telex.com/archives/U...Sound/Drivers/

EV Speakers - Engineering Data Sheet - Product Data Archives
http://archives.telex.com/archives/EV/Speakers/
EV Drivers - Engineering Data Sheet - Product Data Archives
http://archives.telex.com/archives/EV/Drivers/

[lowpoke]

Etone have two reconed EVM 15L drivers on eBay Australia now for $180 each.

[GM]

Originally Posted by fergs1

Greetings peoples , I'm 3/4 way thru a University Classic front horn ( singular for mono) build so I'm committed to either the original University 15" driver(cost a fortune in postage) or its proven replacement (the EVM15L according to klipsch forum).

How would JBL2220A fare

Interesting! The original had an advertised 25-35 Hz Fs which from now dim memory typically meant closer to 35 Hz plus a strong enough motor to allow for being driven with a high output impedance, but later its Qts was raised as required to account for the decreasing output impedance of advancing amp design technology.

By the time University was absorbed by EV and marketed as the 15W, its specs pretty much mirrored the Klipsch K33, Altec 421 and no doubt other brand/models keen to grab some of the market share.

This would make the EVM's Fs too high and the Lab15's Vas too low for best performance, but it will take reverse engineering the horn to find truly optimum driver specs, so my trip down 'Memory Lane' is anecdotal at best.

Still, it begs the question, has anyone posted about using the K33 and its performance in this horn? Seems like it would be the first to try on the Klipsch forum.

Regardless, assuming I'm right about the probable specs, the 2220 then would require a very high output impedance to get the flattest, widest usable bass BW, but still a little less than with a bona fide C15W in good working condition.

GM