EPI-like woofer-tweeter modules

[davidld]

The EPI woofer-tweeter modules on the 70s were highly successful, and currently compete well head to head against moderately-priced DIY projects using modern drivers.

The EPI drivers were interesting in a couple respects. First, the woofer was designed to roll off smoothly at the top at around 1800 Hz, without any passive crossover components at all. Second, the concave dome tweeter was designed to play down low enough to meet the woofer at that low crossover point with just a single 10uF series cap.

I have 2 pr of EPI/Epicure speakers, a sealed pair using the 8 inch woofer and the the larger ported pair using the 6 1/2 inch woofer. They are equal or superior in my view to anything DIY or manufactured costing less than $400-$500 the pair, maybe higher.

These were speakers that in the single module versions in beautiful walnut veneer boxes often sold for under $200 the pair in the early 70s.

My question: If these Asian driver manufacturers and engineers are so smart why has no one seemingly been able to come up with moderately- priced current drivers that can used for projects with the ease and simplicity of the old EPI drivers? When I stick the T/S parameters for the EPI woofer (either the small or large version) into WinISD, they literally blow me away with respect to how deep and smooth the bass goes in a moderately sized box. And the idea of using a crossoverless woofer that just acoustically rolls off smoothly on top drastically simplifies the complexity of the speaker design, and substantially lowers the builder's cost. How is it that current driver manufacturers seemingly somehow forgot what they knew how to do well way back in 1970?

I for one would like to see a $35-$40 8-inch woofer that basically is capable of doing what the EPI woofer did (playing down low yet rolling off smoothly acoustically on top) without any inductor or other crossover parts, and a modern $20 dome genuinely capable of playing smoothly and without complaint down to 1800 Hz or so. This could be sold as a woofer-tweeter module pair along with a cap for the tweeter and plans for a box. I see this as maybe $125 or so in driver and crossover parts for the pair. PE might even offer a veneered or vinyl box designed specifically for the drivers.

Keep in mind, I do own a pair of BR-1's and have spent a lot of time A-Bing my EPI's with them in a direct head-to-head comparison. With respect to my conclusions, I will leave the rest unsaid for now.

David

[robertcottiers]

Re: EPI-like woofer-tweeter modules *PIC*




> The EPI woofer-tweeter modules on the 70s
> were highly successful, and currently
> compete well head to head against
> moderately-priced DIY projects using modern
> drivers.

> The EPI drivers were interesting in a couple
> respects. First, the woofer was designed to
> roll off smoothly at the top at around 1800
> Hz, without any passive crossover components
> at all. Second, the concave dome tweeter was
> designed to play down low enough to meet the
> woofer at that low crossover point with just
> a single 10uF series cap.

> I have 2 pr of EPI/Epicure speakers, a
> sealed pair using the 8 inch woofer and the
> the larger ported pair using the 6 1/2 inch
> woofer. They are equal or superior in my
> view to anything DIY or manufactured costing
> less than $400-$500 the pair, maybe higher.

> These were speakers that in the single
> module versions in beautiful walnut veneer
> boxes often sold for under $200 the pair in
> the early 70s.

> My question: If these Asian driver
> manufacturers and engineers are so smart why
> has no one seemingly been able to come up
> with moderately- priced current drivers that
> can used for projects with the ease and
> simplicity of the old EPI drivers? When I
> stick the T/S parameters for the EPI woofer
> (either the small or large version) into
> WinISD, they literally blow me away with
> respect to how deep and smooth the bass goes
> in a moderately sized box. And the idea of
> using a crossoverless woofer that just
> acoustically rolls off smoothly on top
> drastically simplifies the complexity of the
> speaker design, and substantially lowers the
> builder's cost. How is it that current
> driver manufacturers seemingly somehow
> forgot what they knew how to do well way
> back in 1970?

> I for one would like to see a $35-$40 8-inch
> woofer that basically is capable of doing
> what the EPI woofer did (playing down low
> yet rolling off smoothly acoustically on
> top) without any inductor or other crossover
> parts, and a modern $20 dome genuinely
> capable of playing smoothly and without
> complaint down to 1800 Hz or so. This could
> be sold as a woofer-tweeter module pair
> along with a cap for the tweeter and plans
> for a box. I see this as maybe $125 or so in
> driver and crossover parts for the pair. PE
> might even offer a veneered or vinyl box
> designed specifically for the drivers.

> Keep in mind, I do own a pair of BR-1's and
> have spent a lot of time A-Bing my EPI's
> with them in a direct head-to-head
> comparison. With respect to my conclusions,
> I will leave the rest unsaid for now.

> David

Hi Dave:Is this the EPI tweeter you are referring to?..These are from an EPI model 200 system...I was going to throw the tweeters out,but I can save them if you want them.I still have the cabinets which are in great condition.

Bob C.

[davidld]

Re: EPI-like woofer-tweeter modules


> Hi Dave:Is this the EPI tweeter you are
> referring to?..These are from an EPI model
> 200 system...I was going to throw the
> tweeters out,but I can save them if you want
> them.I still have the cabinets which are in
> great condition.

> Bob C.

I would love to have those tweeters as spares as they are exactly the same as the ones in my Epicure 10's, one of which is just a bit "iffy"
Drop me a note at <A HREF="mailto:[email protected]">[email protected] m</A> and I will compensate you for postage and a little extra as well via paypal.

Those tweeters gradually and smookthly roll off about 2 db per octave above 4000 Hz, but the dispersion remains very good way high up. They don't sound quite as bright as a contemporary dome that is linear to above 15,000 Hz. Some see that as a plus not a minus. Indeed they were highly regarded for broad dispersion back in the 70s, when most speakers were still using cones.

David

[unknownuser]

Re: EPI-like woofer-tweeter modules

Provided Link: http://www.humanspeakers.com


Here's a link you might find interesting, if you haven't already seen it that is.

I am curious how you would compare your EPI's to your BR1's.

Mike


(Originally posted by: mchowdy)

[bogie]

Re: EPI-like woofer-tweeter modules


My take... BR-1 are more rockin' speakers. The EPIs worked very well with jazz.

> Here's a link you might find interesting, if
> you haven't already seen it that is.

> I am curious how you would compare your
> EPI's to your BR1's.

> Mike

[davidld]

Re: EPI-like woofer-tweeter modules


> Here's a link you might find interesting, if
> you haven't already seen it that is.

> I am curious how you would compare your
> EPI's to your BR1's.

> Mike
I'm very familiar with that link.
The EPI's are far smoother in the mid range and go deeper in the bass. They roll off a bit (about 2 db per octave above 4 KHz in direct comparison,

I admit, I'm a jazz not rock fan.

Winslow Burhoe, who founded EPI is still building speakers. See his link at <A HREF="http://www.directacoustics.com">www.directacoustics.com</A> He has a $500 pr of speakers very similar to the EPI 201. A ported design with an angled top panel. He claims they are the best speakers he ever built, except perhaps for the big EPI 1000 4-module towers.

[bogie]

Re: EPI-like woofer-tweeter modules


Those things transmission lines? Also, he's using crossovers now... 18db....

> I'm very familiar with that link.
> The EPI's are far smoother in the mid range
> and go deeper in the bass. They roll off a
> bit (about 2 db per octave above 4 KHz in
> direct comparison,

> I admit, I'm a jazz not rock fan.

> Winslow Burhoe, who founded EPI is still
> building speakers. See his link at
> <A HREF="http://www.directacoustics.com">www.directacoustics.com</A> He has a $500 pr of
> speakers very similar to the EPI 201. A
> ported design with an angled top panel. He
> claims they are the best speakers he ever
> built, except perhaps for the big EPI 1000
> 4-module towers.

[dlr]

Looks more like he's doing 4th order


> Those things transmission lines? Also, he's
> using crossovers now... 18db....

According to this page:

<A HREF="http://www.directacoustics.com/specs.htm">http://www.directacoustics.com/specs.htm</A>

According to this page, he's crossing at 1600Hz, 4th order. From the page:

"The woofer is designed mechanically and electrically to roll off naturally, no additional filtering is necessary from the crossover. A two pole network adds to the natural rolloff of the tweeter, additional components equalize the tweeter response to achieve maximum flatness in the prescribed room location."

So he's crossing the woofer to get 4th order. That low an Fc for a 6.5" and it has to be a 3rd or 4th order electrical. I haven't seen a driver that size that has the knee low enough to do it with less than this. It sure looks like he's not using the driver's natural lowpass.

The tweeter has a second order network that apparently works with the driver's 2nd order highpass to get 4th order.

Not much unique in any of this other than the severe upward angle of the drivers.

But he does use some unusual descriptive terms, like this:

"The speaker is designed to slide the sound smoothly into the room from its assigned position, without causing resonances or interferences.".

I can't say that I've ever heard music "slide into the room".

dlr

[spence]

Re: EPI-like woofer-tweeter modules


I've owned several pairs of EPI speakers starting with the 70's back in their heyday. I eventually moved up to the 20+. During the sales process, they played Virgil Fox on a pipe organ. It was a direct to disk recording that had bass into the 20's. I must say that I was impressed with the low end performance of the speakers. The EPI had long throw woofers (for their day). The highs were just so-so for my teen ears back then. The 20+ speakers are long gone, but now I find that I prefer that laid back sound.

BTW: I ran across a set of the 400's the other day at a thrift store. I'm not gonna tell you how much I paid for them because you'll cry. They're in storage now. They need the surrounds replaced on all 8 woofers (4 per speaker) but there's no doubt that will be on my to-do list. The 400 was the little brother to the 1000, a speaker which I heard once. In those pro-EPI days that 1000 audition made tears come to my eyes.

I've seen some Vifa woofers that have that smooth roll off at the high end, albeit a lot higher in frequency than the EPI woofers claim to roll off.

SW

[scottc]

Re: EPI-like woofer-tweeter modules


> The EPI woofer-tweeter modules on the 70s
> were highly successful, and currently
> compete well head to head against
> moderately-priced DIY projects using modern
> drivers.

> The EPI drivers were interesting in a couple
> respects. First, the woofer was designed to
> roll off smoothly at the top at around 1800
> Hz, without any passive crossover components
> at all. Second, the concave dome tweeter was
> designed to play down low enough to meet the
> woofer at that low crossover point with just
> a single 10uF series cap.

> I have 2 pr of EPI/Epicure speakers, a
> sealed pair using the 8 inch woofer and the
> the larger ported pair using the 6 1/2 inch
> woofer. They are equal or superior in my
> view to anything DIY or manufactured costing
> less than $400-$500 the pair, maybe higher.

> These were speakers that in the single
> module versions in beautiful walnut veneer
> boxes often sold for under $200 the pair in
> the early 70s.

> My question: If these Asian driver
> manufacturers and engineers are so smart why

> has no one seemingly been able to come up
> with moderately- priced current drivers that
> can used for projects with the ease and
> simplicity of the old EPI drivers? When I
> stick the T/S parameters for the EPI woofer
> (either the small or large version) into
> WinISD, they literally blow me away with
> respect to how deep and smooth the bass goes
> in a moderately sized box. And the idea of
> using a crossoverless woofer that just
> acoustically rolls off smoothly on top
> drastically simplifies the complexity of the
> speaker design, and substantially lowers the
> builder's cost. How is it that current
> driver manufacturers seemingly somehow
> forgot what they knew how to do well way
> back in 1970?

> I for one would like to see a $35-$40 8-inch
> woofer that basically is capable of doing
> what the EPI woofer did (playing down low
> yet rolling off smoothly acoustically on
> top) without any inductor or other crossover
> parts, and a modern $20 dome genuinely
> capable of playing smoothly and without
> complaint down to 1800 Hz or so. This could
> be sold as a woofer-tweeter module pair
> along with a cap for the tweeter and plans
> for a box. I see this as maybe $125 or so in
> driver and crossover parts for the pair. PE
> might even offer a veneered or vinyl box
> designed specifically for the drivers.

> Keep in mind, I do own a pair of BR-1's and
> have spent a lot of time A-Bing my EPI's
> with them in a direct head-to-head
> comparison. With respect to my conclusions,
> I will leave the rest unsaid for now.

> David

David,
Have you used the GR-Research M-130? It has a remarkably smooth roll off, excellent detail, and surprisingly strong bass for a 5 1/2".

[dfaulds]

Re: EPI-like woofer-tweeter modules


Actually, I don't think these are available anymore. I seem to recall that Winslow had only sold a few dozen pairs, so he discontinued production some time ago.

Please correct me if I am wrong.

> Winslow Burhoe, who founded EPI is still
> building speakers. See his link at
> <A HREF="http://www.directacoustics.com">www.directacoustics.com</A> He has a $500 pr of
> speakers very similar to the EPI 201. A
> ported design with an angled top panel. He
> claims they are the best speakers he ever
> built, except perhaps for the big EPI 1000
> 4-module towers.

[davidld]

Re: EPI-like woofer-tweeter modules


> Actually, I don't think these are available
> anymore. I seem to recall that Winslow had
> only sold a few dozen pairs, so he
> discontinued production some time ago.

> Please correct me if I am wrong.

Winslow was out of production for a year or more. At one time he indicated his Asian woofer supplier was no longer in business and finding a suitable alternative (that rolled off smoothly on top in its own) required a lot of effort, but he did find a new woofer, slightly less efficient he said and as a consequence the crossover needed to be reworked. The recent info says all of that is done and the speakers are ready to be shipped again.

I have no idea where he is pulling his woofers from now, tho I would speculate a company similar to the Indian company that supplies woofers to Danny and GR Research

For fans of EPI, the slanted-top design is not odd at all but very familiar as it is a takeoff of the popular and highly regarded epi 101/201 design.

OK so here you have a guy with one of the best resumes in the entire speaker building business, selling a design he clearly loves and regards as his best effort ever, with a price tag that would be considered cheap by todays standards even among DIYers. I suppose we can all just ignore that and go back to our DIY projects. But please don't just reject the "odd" design out of hand.

[davidld]

You realize of course


that the four-module EPI 400's were one of a tiny handful of speakers that Julian Hirsch at Hirsh-Houk labs) truly adored over his years in doing reviews at Stereo Review. They were much easier to live with than the big 1000 units. The 400 speakers were also a Winslow Burhoe design, I believe.

I always thought it odd no one here attempts to do a 400 clone using modern drivers. These call for a 6 1/2 inch woofer and dome tweeter on each of the 4 tower sides, all in about 2 cu ft. 36 or 38 inches high. More construction details can be found on humanspeakers.com

[severius]

EPI -- Finest Speakers Ever Made *NM*

[winslowburhoe]

As the designer of the EPI module, it gives me great pleasure to read these posts. I would be happy to answer any questions.