Jump to content
The Classic Speaker Pages Discussion Forums
thiptoman

EPI 100's

Recommended Posts

This question is for technicians or engineers. Has anyone ever seen a graph of the EPI 100's frequency response ? At what points does it deviate from flatness ,what frequencies tend to stand out?

Share this post


Link to post
Share on other sites

As we know, the EPI 100 was a fairly conventional 8", 2-way sealed design from the mid '70's. It was roughly the size of the AR-4x, but used a novel 1" inverted dome tweeter. Early versions used silicon grease in the gap for cooling--a technique that Roy Allison used at AR on the 6 and 7's tweeters, I believe, in the days before ferrofluid cooling was introduced. Win Burhoe probably learned that when he worked as an engineering tech under Roy at AR.

There is some confusion as to whether AR or EPI was the first company to introduce the ferrofluid-cooled tweeter to the market in the mid 70's.

Anyway, I spoke to a few of my "sources" who know all about the speaker, and this is what else I found out about the 100:

The goal was for the speaker to be reasonably flat in response, but with as "Cheap a f****n' crossover as possible." That's a direct quote from "someone who was there." The 100 had a single capacitor on the tweeter, while the woofer ran flat out, as high as it could go. Sometimes, it didn't make it uniformly all the way to the 1800Hz crossover, so the iffyist part of the response was the midrange, between1000-2000Hz, which could get pretty rough.

The tweeter was remarkably extended and smooth. The 100's strong high end response, compared to the AR's rolled off high-end response and the Advent's midrange forwardness, could make the EPI sound sizzly on the high end. That, coupled with a midrange that could dip by a few dB before crossing over to the tweeter, gave the 100 a reputation for having a prominent high end.

EPI used to supply individual curves with each speaker they shipped. My source recalled that those curves were very accurate, "even if they had to occasionally push the pen on the graph writer to where they wanted it to go!"

Steve F.

Share this post


Link to post
Share on other sites

Here is a response on an EPI 110. It's very similar to the 100. Note the smooth woofer response in the nearfield measurement.

post-100237-0-60459400-1387252940_thumb.

Share this post


Link to post
Share on other sites

Yup, very similar speakers, at least by these specs. Am curious as to what would prompt the introduction of a new model. The drivers are the same - - - is it just the cabinet volume which might improve performance?

post-112624-0-62791200-1387335039_thumb.

Share this post


Link to post
Share on other sites

I estimate the volume difference to be only a few %. Hu is selling the same exact drivers for both models. It's best to ask Hu what the differences might be. He's the best authority on these speakers I know of.

Share this post


Link to post
Share on other sites

As we know, the EPI 100 was a fairly conventional 8", 2-way sealed design from the mid '70's.

The goal was for the speaker to be reasonably flat in response, but with as "Cheap a f****n' crossover as possible." That's a direct quote from "someone who was there." The 100 had a single capacitor on the tweeter, while the woofer ran flat out, as high as it could go. Sometimes, it didn't make it uniformly all the way to the 1800Hz crossover, so the iffyist part of the response was the midrange, between1000-2000Hz, which could get pretty rough.

Steve F.

Interestingly, all of the mid 70's, post AR-4x, 8 inch woofer counterparts (AR-4xa, 6,and 7...as well as the 10 inch woofer AR-8) also had full range woofers and single cap crossovers. The later AR-18 was the same. The lesser known Avid 100 was also designed in this way, and along with the EPI 100 (and its siblings), was easily in the same league as these AR models. (I personally prefer both the Avid's and EPI's over the AR's in this category).

Roy

Share this post


Link to post
Share on other sites

Let's not forget the Dynaco A25 whose 10" Seas woofer dropped off very pleasingly on its own with no help from the crossover.

Share this post


Link to post
Share on other sites

Let's not forget the Dynaco A25 whose 10" Seas woofer dropped off very pleasingly on its own with no help from the crossover.

Another great example of an excellent speaker with a very simple crossover! Probably my favorite of all the speakers mentioned in this thread.

Share this post


Link to post
Share on other sites

Hi vintage speaker lovers! I live in Holland, and i absolutly love the Epi 100V's!! I have a pair that a bought from Ebay. Epi or Epicure was never sold here in Holland, so, i think that my 100V's are the only pair in Holland. When they arrived, the woofersfoam was gone, and the glue on both tweeters was cracked and both tweeters were laying inside the cabinets. I refoamed the woofers, and glued the tweeters with special glue kit from Patex. The sound is so real, so fresh! And the low's... Wow!! Deep tight bass, far better bass than the AR4x.          These are keepers and never leave my house!! 

Greetings  Robby

 

 

20140725_210133.jpg

Share this post


Link to post
Share on other sites

Great little speakers - - I was just listening to mine in the bedroom this morning while tuned into my favorite Sunday morning radio program, Blues Hangover. Your woofer re-foam looks good and am pleased to hear you were able to repair the tweeters. You might want to consider replacing that single 10uF cap next time you have the opportunity.

Nice to hear that some EPI's made it to Holland. Similar performance, but my pair is a bit earlier, with rubber woofer surrounds, masonite tweeters, and walnut veneer cabs. Same black grille cloth, though. 

When you need additional help or seek information, look here.

http://www.humanspeakers.com/e/index.htm

epi-100.jpg

Share this post


Link to post
Share on other sites

Thank you very much RaRa, you Epi's look very nice!! Thats the 100M?  I have collected very nice vintage US speakers over the years. Here are some pics.. iam searching for empty 100V cabinets, because i have 2 tweeters and 2 woofers as a spare. I want to make another nice pair with these parts, but i want the original Epi 100V cabinets. In fair condition is good enough for me. Maybe you can help me? Or other forummembers?   Ive almost bought a pair of Ebay again, but the seller want $150?? for shipping only. He's out of his mind!! 

 

Thanks in advance

Greetings Robby

20140621_082436.jpg20140117_070605.jpg20140117_070605.jpg

 

 

IMG_20150807_103954.jpg

IMG_20151028_072716.jpg

Share this post


Link to post
Share on other sites

Re: EPI, Burhoe developed so many model numbers using the same two excellent drivers that it can get confusing identifying the correct model, but yes, according to this link I guess what I have is known as the M100's.

http://www.humanspeakers.com/e/epi100.htm

Your collection looks great - - a nice AR-4x, a very nice AR-2x, an AR-8 - - but I'm curious about that last pair shown. They appear to have a very nice pair of 4x woofers, but are showing the tweeters from the AR-4. Do you know if these drivers are all original, and do the speakers have labels on the backside? Have you looked inside at the crossovers?

Meanwhile, will keep on the lookout for EPI cabinets, but I'm sure it would cost more for shipping from USA than the cost of the cabs themselves. I'd suggest trying to locate a pair with real walnut veneer perhaps. 

Share this post


Link to post
Share on other sites

Hi Ra.Ra, yes your absolutly right, this is a AR4x. But when i bought them, there were Philips tweeters mounted in the baffles. The AR mid/high units i had them for spare for my AR2xes. So, its not original, but pretty close. Ive changed the tweeter cap wich was original 20Uf, to 10Uf and they sound even beter in high's than the original tweeter.                                                           Here are some other babys from my collection.

Have a nice day en greetings Robby20140410_115528.jpg

 

Screenshot_2016-02-09-11-25-57.jpeg

IMG_20151113_105921.jpg

IMG_20150614_145110.jpg

20131210_145323.jpg

Share this post


Link to post
Share on other sites

Great collection - - - I hope the people that follow the AR forum are reading over here in the EPI forum. Your latest pics look like AR-7's, 4xa's, 12's and 6's. Your 4x's with the 2ax HF driver undoubtedly perform better with the 10uF cap, but that could be improved further if you use a 6uF cap just like the original AR-4 and AR-2ax which used this driver.  Nice pics, thanks.

Share this post


Link to post
Share on other sites

Hi RaRa, i have, to be exact, 2 pairs AR2x, old en newer model, 2 pair AR4x's, 2 pair AR4xa's, an nice pair AR6, that comes close in overall sounding to the Epi 100, 2 pair AR7, and a pair AR8 wich is also very rare in Holland, a pair of KLH Model 32's, the AR12, very nice sounding speakers! And of course my wonderful Epi 100V's. The lowend on these fantastic speakers should people think there were dealing with 10" woofers instead of 8". Everyone who listen to them ask: what kind of brand is this? They sound wonderful!  By the way, i did replace the capacitor on the AR4x with 6Uf not 10Uf. I checked it and your right! My mistake..

Greetings Robby and have a nice evening! ?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...