Suitable Drivers for University Classic bass horn Cab

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fergs1

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Joined 2005
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
 
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lowpoke

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Joined 2009
homebuilthifi.com
fergs1 said:
... its proven replacement (the EVM15L according to klipsch forum). I live in Australia and finding these units is proving to be very hard.
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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

Inductor

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Joined 2006
cyclotronguy said:
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
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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/EV/Speakers/EDS/EVM-15L Series II EDS.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

Inductor

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GM

GM

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Joined 2003
fergs1 said:
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
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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
 
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fergs1

Member
Joined 2005
Greetings peoples and thankyou for all the replies, I have a pdf I found on the nt which is a flare analysis of the University Classic and I've been trying to upload it for the last 3 days. Lets see what happens now http://forums.klipsch.com/forums/storage/3/861979/Flare Analysis_Classic.pdf
By gad I think he's done it! Would this make it easier to determine which drivers of a new or readily available nature would be suitable.. cheers fergs
 
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lowpoke

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Joined 2009
homebuilthifi.com
fergs1 said:
By the way Lowpoke I had seen those evm15l 's on the bay but after contacting the guy I still haven't heard from him in 2 weeks. Doesn't inspire confidence, but thanks for the heads up anyway. cheers fergs
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fergs, fear not.
Etone is a large and reputable company. I suspect their ebay business is probably manned by a single employee. Giving them a call might yield more satisfactory results. But these are decent drivers at what I would consider a good price. (It's less than I paid for mine in original condition.)
 
weltersys

weltersys

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Joined 2008
fergs1 said:
bump
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The EV15L has a curvaliniar cone, it has more upper breakup than the 15B.

For horn load, I preferred the 15B, which has a normal conical shape. The conical 15B is cleaner and has more LF, the 15L has more (dirty) top end.

There are several Eminence cones in the Delta and Kappa line up that would perform well in your horn, and may be cheaper than used EV which may have funky cones, or have been reconed with shoddy parts.

Your choice will be more LF or more HF, the cones with more Xmax will perform better down low, the ones with less will be louder up higher.
 
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