audiomagnate
Addicted Member
I can't seem to find a FR graph for any EPI speakers. I just want to see a curve for the classic inverted dome EPI tweeter. I'm working with an M60, but an 100 graph will do.
Vintage EPI Frequency Response
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cablephil212
Super Member
Not happ-nin'. I too have looked and came up with nada. Not even a hint on the Human site or the net.
I would love to find a FR on any of those inverted tweets. Somewhere I read that they have a huge dip at 10k, but I'll be damned if I can hear that.
I do have a RS sound level meter. When (and if) I get a free weekend, I plan on taking 1 tweet out and doing a freq test tone sweep on it. I also have to find my printed "freq correction sheet" for the meter. When this happens, I have no problem shooting you a PM of what I find.
I hope you're not in a rush, 'cause this may take a while. Best I can do with the holidays coming up.
To You and Yours, Happy Holidays.
I would love to find a FR on any of those inverted tweets. Somewhere I read that they have a huge dip at 10k, but I'll be damned if I can hear that.
I do have a RS sound level meter. When (and if) I get a free weekend, I plan on taking 1 tweet out and doing a freq test tone sweep on it. I also have to find my printed "freq correction sheet" for the meter. When this happens, I have no problem shooting you a PM of what I find.
I hope you're not in a rush, 'cause this may take a while. Best I can do with the holidays coming up.
To You and Yours, Happy Holidays.
Jeff K
Super Member
I'm pretty sure High Fidelity mag did FR plots for a few EPI's back in the 70's. I don't know of anyone that has old issues. CR may have done some as well.
Seems like it would be pretty easy for someone in the DIY community to do, also.
One of these would work if you know someone that has one.
http://www.parts-express.com/dayton-audio-omnimic-v2-precision-measurement-system--390-792
Seems like it would be pretty easy for someone in the DIY community to do, also.
One of these would work if you know someone that has one.
http://www.parts-express.com/dayton-audio-omnimic-v2-precision-measurement-system--390-792
audiomagnate
Addicted Member
There are old HIFI and Audio mags on line now, but they only go up to around 1962. I guess I'll just have to get a mic and do it myself, but I really want to know how they tested when they were new.
audiomagnate
Addicted Member
Sorry, but 110s use a cheap cone tweeter, not even close. 60's and 100s use the original inverted dome paper air spring tweeter.
spkrdtr
spkrfixer
IIRC, this customer's pair had the inverted dome (for whatever reason). They sure sounded as good as they tested.
audiomagnate
Addicted Member
That's an impressive curve! Now that I think about it, I seem to recall that there was an earlier version 110 that used the same drivers as the 100 in a slightly larger cabinet. I was referring to the MKII:
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spkrdtr
spkrfixer
Here's a pic of the EPI 110 at the best website for EPI.
http://www.humanspeakers.com/e/epi110.htm
The pic shows an inverted dome tweeter. The specific model I tested was the EPI110C.
http://www.humanspeakers.com/e/epi110.htm
The pic shows an inverted dome tweeter. The specific model I tested was the EPI110C.
jwalker
Well-Known Member
This link shows the metal inverted dome that Human makes somebody plotted. I have measurements of the phenolic and linen versions somewhere and they did not look like this plot. Either the metal dome sample tweeter was defective or changing the diaphragm broke the design.
http://www.audioheuristics.org/meas...02 tweeter/human_speakers_pro_002_tweeter.htm
http://www.audioheuristics.org/meas...02 tweeter/human_speakers_pro_002_tweeter.htm
spkrdtr
spkrfixer
The 110C I measured had the gold ring tweeter face plate like that shown in the Human link I posted. IIRC, the dome was inverted and was linen.
The 002 Human tweeter Heuristics tested looks somewhat problematic. Howver, in deference to Human's efforts to provide vintage speaker parts for EPI and others, one data point (i.e. a single tweeter test) does not make an average performance.
The 002 Human tweeter Heuristics tested looks somewhat problematic. Howver, in deference to Human's efforts to provide vintage speaker parts for EPI and others, one data point (i.e. a single tweeter test) does not make an average performance.
audiomagnate
Addicted Member
mhardy6647
Lunatic Member
I think it's paper impregnated with something (a phenolic resin, methinks).
The FR plots - even allowing for, I'm sure, significant smoothing - are pretty impressive for what was a low-priced loudspeaker from the early 1970s.
The FR plots - even allowing for, I'm sure, significant smoothing - are pretty impressive for what was a low-priced loudspeaker from the early 1970s.
spkrdtr
spkrfixer
IIRC, those were smoothed 1/6th octave - pretty standard.
Back in 1973, new EPI 100's were shipped with paper Bruel & Kjaer graphs showing each speakers unique response .
RE the tweeters response ; both of my graphs show 5db deep holes, centered at @ 14K ( & more than 1/2 an octave wide )
- 1.5K to 10K is pretty flat ( at +/- 2db ) .
I could take a pic ( & post the results ) / though I'm ensure if I want to participate in unraveling a legend .
Perhaps it's worthwhile reminding people that Dr. Geddes focuses on the response from 1K to 10K ( for HF ).
RE the tweeters response ; both of my graphs show 5db deep holes, centered at @ 14K ( & more than 1/2 an octave wide )
- 1.5K to 10K is pretty flat ( at +/- 2db ) .
I could take a pic ( & post the results ) / though I'm ensure if I want to participate in unraveling a legend .
Perhaps it's worthwhile reminding people that Dr. Geddes focuses on the response from 1K to 10K ( for HF ).
Putterman
Super Member
http://new-hifi-classic.de/Gallery_MO/index.php?cat=34
This is the address of the Michael Otto website which has info on EPI and many other brands. I've downloaded a copy of the manufacturer FR from his website. (Thanks Mike!)
The EPI 110 shown is from the Harman era who acquired the EPI name in the 1980's and used it to churn out cheapo budget speakers.
This is the address of the Michael Otto website which has info on EPI and many other brands. I've downloaded a copy of the manufacturer FR from his website. (Thanks Mike!)
The EPI 110 shown is from the Harman era who acquired the EPI name in the 1980's and used it to churn out cheapo budget speakers.
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audiomagnate
Addicted Member
Uh, that doesn't look too good. That is a massive suckout near the crossover point. Interesting.
I have measured a few of the Genesis version(s). They vary a bit, but the top two octaves always looked pretty similar. Unfortunately I only kept a single basic measurement because that was all I needed for what I was doing, and I didn't really note the conditions either.
I still have six of these in the house and would probably be willing to do a more thorough job and post results if somebody wants, or if anyone wants to send me an EPI or Human one to compare.
This is farfield about 1° off-axis (vertical) on a narrow baffle, room reflections gated out (SPL shown is about 20dB higher than actual):
Here's a speaker I designed with the same (response below 700Hz not accurate in this graph):
I still have six of these in the house and would probably be willing to do a more thorough job and post results if somebody wants, or if anyone wants to send me an EPI or Human one to compare.
This is farfield about 1° off-axis (vertical) on a narrow baffle, room reflections gated out (SPL shown is about 20dB higher than actual):
Here's a speaker I designed with the same (response below 700Hz not accurate in this graph):
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