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All EPI 8" are not created equal...

hbucker

hbucker

Well-Known Member
I've got a pair of EPI 100's that I recently replaced the woofers on. All of the info I've found says that the EPI 8" woofers are generally created equal on similar speakers. Mine were supposedly taken out of a set of M180 speakers (which use the same replacement speaker from Human). My replacement woofers do indeed appear to be authentic, 1979 EPI woofers reading 8 ohms... I haven't been impressed with the low end produced by these woofers, but it is acceptable. They are nice sounding speakers.

Today I got a pair of 100's at GW for 5$. Woofers need refoaming, but appear to be authentic, 1978, EPI woofers.... 4 ohms. I plugged them in just to see if they were working (low volume) and they worked fine. They also seem to have noticeably more low end punch than the 8 ohm pair, although a fair comparison isn't possible until they are refoamed.

I've always heard that among comparable speakers, the EPI 8" woofers were the same. This doesn't appear to be the case.

Would 4 ohm woofers produce more low end punch than 8 ohm woofers?
 
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I would imagine that given the same volume setting at the amp, the 4ohm drivers would seem to give more bang for the buck. The amp (generally speaking) is producing more output watts when presented with the lower impedance load.

Dave
 
Fed an identical input of power, a 4 ohm woofer will sound louder than an identical woofer of 8 ohms impedance. That may explain the sensation you are experiencing. I wouldn't run those woofers again until you re-foam them.
 
EPI made several versions of their 8" woofer. AFAIK, the woofer in all iterations of the 100 were 8 ohms. Your 4 ohm woofers may well be EPI, but not necessarily made for the 100's.

Dave
 
Low-impedance woofers were used in some multiple-woofer designs, like the 1000.

Check that you have sealed the speaker to the box, remembering to check the terminal cup, as well.
 
So the consensus seems to be that the 8 ohm speakers are correct and that the 4 ohm speakers may not be authentic 100 drivers, but replacements? They do appear to be EPI's though.

Weighing my options as to whether refoaming the 4 ohm drivers would provide a worthwhile boost in the low end, or if it would be generally a waste of money and time.

Thanks for your replies.

P.S. DC resistance on the speakers are said to be 4 ohm with nominal at 8 ohms. The speakers I picked up at GW today had dc at 4 ohm... Just to illustrate my confusion here.
 
hbucker said:
So the consensus seems to be that the 8 ohm speakers are correct and that the 4 ohm speakers may not be authentic 100 drivers, but replacements? They do appear to be EPI's though.

Weighing my options as to whether refoaming the 4 ohm drivers would provide a worthwhile boost in the low end, or if it would be generally a waste of money and time.

Thanks for your replies.

P.S. DC resistance on the speakers are said to be 4 ohm with nominal at 8 ohms. The speakers I picked up at GW today had dc at 4 ohm... Just to illustrate my confusion here.
Click to expand...

All the "typical" EPI 8" woofers I've seen have been closer to 4ohm DC. There is also a 2ohm DC version. The 2ohm variety was used in the 601/602 and a 2ohm model was also used in the Genesis 66. The "4 ohm" variety is the common one seen in the bulk of the EPI "module" speakers.

Based on my experience the 8ohm DC EPI woofer would be the unusual one...
 
Interesting jw. thx.

Dumptruck: Thanks for the link but that page has been more a source of my confusion than resolution. I understand the info. My results on this end have been different.
 
I might get motivated to finally refoam a pair of 100v sitting around, I'll see what those are. I do remember getting a pair once (or maybe they were T/E 100s) whose woofers looked identical, but when I pulled them, one had a round magnet and the other a square.
 
I recently repaired a 1979 set of EPI 100's that were all original. The woofers read 4 ohms on my multimeter.
 
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