Driver choice for use in Edgar mid-bass horn!

[spkrman57]

This should be a simple decision for the experts out there.

I have a E-130/2225 and a E-140 for 100hz front loaded horn duty.

I ordered the horn from Bruce today and while it takes a long time for Bruce to actually get the horns to me, I thought I would gather opinions on which 15" JBL driver to actually use in this horn.

E-130/2225 (recone - thread info already in this forum) has 98.5 db/Qts=.226
E-140 has 100 db/Qts=.17 (aluminum dust cap replaced with paper)

In theory, I would like to go with the more efficient driver as I am using 45 SET amps for 2 wpc. By horn-loading will add approx 6 db.

I have a feeling the answer comes down to which one will have the flatter response used in this scenario.

So, should I go with the E-140 and have surgery performed to change the dustcap to paper, or maybe the E-130/2225 might have the flatter response????


So here I am again asking the pros for their advise. I realize I am one of the few tubes and horns fan club member, but I love the sound of a good 45 SET amp!!!

The expected response will be 100hz to 800hz and will be using 1st order crossovers. Great Plains 399 driver(1.4" same as 288-8K) on round tractix horn takes over at 800hz.


Simple decision here, which driver to use????????

Regards, Ron

[edgewound]

This should be a simple decision for the experts out there.

I have a E-130/2225 and a E-140 for 100hz front loaded horn duty.

I ordered the horn from Bruce today and while it takes a long time for Bruce to actually get the horns to me, I thought I would gather opinions on which 15" JBL driver to actually use in this horn.

E-130/2225 (recone - thread info already in this forum) has 98.5 db/Qts=.226
E-140 has 100 db/Qts=.17 (aluminum dust cap replaced with paper)

In theory, I would like to go with the more efficient driver as I am using 45 SET amps for 2 wpc. By horn-loading will add approx 6 db.

I have a feeling the answer comes down to which one will have the flatter response used in this scenario.

So, should I go with the E-140 and have surgery performed to change the dustcap to paper, or maybe the E-130/2225 might have the flatter response????


So here I am again asking the pros for their advise. I realize I am one of the few tubes and horns fan club member, but I love the sound of a good 45 SET amp!!!

The expected response will be 100hz to 800hz and will be using 1st order crossovers. Great Plains 399 driver(1.4" same as 288-8K) on round tractix horn takes over at 800hz.


Simple decision here, which driver to use????????

Regards, Ron

Hi Ron...

I suspect that considering the range of frequencies for your intended use, it could be a push....6 to 1/half dozen to the other. The E130 frame(?)/2225 recone and the E140 have the same magnet structure. The 2225 and E140 cone are the same, but the 2225 voice coil is slightly longer than the E140. The tilt might be to the 1.5dB advantage in senitivity to the E140 considering you're using such modest power. Excursion probably means nothing in this range....so..what would I do?. I'd try the E130/2225 first, and then swithch to the E140. Why? Because you're ears will probably lean toward the E140 as being a closer match to the sensitivity of the 399 driver and require less balancing between the two....and you'll only have to change the speaker out once...what'cha think....yes?...no?

[Earl K]

Ron,

- Put your "Woofer Tester" on your hybrid E130/2225 and obtain the new TS parameters .

- You should find that this combo now has a lower Qts than the stock figure quoted for a 2225.

- The E130/2225 hybrids' efficiency ( in the midrange area ) will also be slightly elevated due to TS changes .

- Once you're finished this measuring process / don't be too surprised to find this E130/2225 hybrid isn't much different than the E140 with the paper dust cap .

- Still, given the opportunity to choose between the two transducers , I'd try both / measure & listen to the results and then "retire" the one that didn't make the cut .

- If I had to choose before the event, I'd choose the E140/paper-cap hybrid.

[spkrman57]

Edgewound and Earl K.,

Originally I thought the E-140 with its more efficient output would only get beat out by the E-130/2225 might have a flatter response due to the cone/voice coil properties. I can't remember for sure, but I think the E-140 has a longer voice coil which might make the E-130/2225 closer to a "underhung" voice coil which from everything I have read in the past would have a better "control" as the same amount of voice coil would most of the time would be in the gap.


If I use the E130/2225 for horn duty, then the E-140 would see duty in a Altec 1234 cabinet (Large approx 12 cubic ft) and run a 511B horn/1" driver for a very large EBS alignment something like the old D130 systems were done back in the day when one would use a 14 cubic ft cabinet to impress their friends.


It seems overall that these drivers are more similiar than different. By not messing with the aluminum dust cap on the E-140, I can use it as a nice SET speaker system for the basement.


Thanks to both of you for your information!!!



Ron

[edgewound]

Ron,

FYI...the 2225 has the longest coil of these drivers. I'm understanding that you have an E130 frame reconed with a 2225 kit, correct? Or is it vise-versa? The 2225 kit has a moderate overhung coil/gap. Coil is .63", gap is .28". The E140 has a less slightly overhung coil/gap with coil of .45" and gap depth of .28. The E130 has a equal length coil/gap both at .28" for highest efficiency. The E-130/140 magnet is bigger than the 2225 magnet with more flux denisty 1.35T vs. 1.2T. Also, FYI, the E130 has an aluminum voice coil vs. copper for the E140 and 2225. The aluminum coil will have less inductance and therefore stronger mid and high response. Just thought you might like to know this info.
Thanks.

[spkrman57]

It seems that since I have time until I get the horns, and the 130/2225's are currently in use in the main system, I will wait until I can test all 4 drivers on the WT2 and see the results and decide at that time.
Ron

[spkrman57]

See "Saga of a pair of E-140's that measure off" thread in this forum.


I have decided to have the E-140's reconed to E-130's with paper dust cap being the only modification to the driver.

I will post results in the future when the recone/break-in has been completed and the install in the Edgar midbass horns takes place.

Ron