Elgrau's speaker project

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OconeeOrange
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Elgrau's speaker project

Post by OconeeOrange » Mon Dec 29, 2014 5:08 pm

Another member - elgrau is also making speakers now that he is retired from his job as a rocket engineer.
They are off the chart.

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Toy Maker
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Re: Elgrau's speaker project

Post by Toy Maker » Mon Dec 29, 2014 6:56 pm

That's cool to hear! I'd love to see the progress of these as well.
So much so, that I made this his own speaker build thread. So post away so we can all follow the progress.

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Re: Elgrau's speaker project

Post by elgrau » Tue Dec 30, 2014 3:46 pm

Perhaps when I find the time...also "refining" the ~20 step recipe for building the cabinets (that I'd be glad to share if anyone was interested) of these EPI M250 "clones" that Huw of humanspeakers.com (and blessed by the original designer - Winslow Burhoe) modded. I use ash wood dowels to butt joint the MDF side panels to the much stiffer ~1"x1" walnut (or any HW..) side posts which VERY much stiffens up the boxes (also added a corner brace to the weakest area of the MDF sides where the woofer/tweeters come together).

Also came upon some rough sawn 1" walnut boards that I plane down to 7/8" and use for the solid walnut 14"x14" tops/bottoms of these 36" high speakers (which also allows the front top edges to be rounded over for better sound wave dispersion...? This would be near impossible to do with veneered MDF tops...). The 1st set of these (with burled Mappa veneered sides) I gave to my son as a BD present (shown here with the grills taped on...before I added magnets glued to the grills that attach them to the two woofers):
IMG_3937 (Small).JPG
IMG_3937 (Small).JPG (64.88 KiB) Viewed 904 times
Here's a closeup of the beautiful solid walnut top of one of them - oops, out of focus :( :
IMG_3924 (Small).JPG
IMG_3924 (Small).JPG (31.3 KiB) Viewed 904 times

Have walnut for two more sets of these M250 "clones" and I'm building set #2 (using burled white ash veneer for the sides instead of burled Mappa..). Drivers could be vintage EPI drivers or humanspeakers.com sells brand new "EPI" drivers for these (and I use their wiring harness/speaker terminals/exact spec x-over caps assembly that Huw sells for $38 each - great deal as you can easily spend that on the 10 uf audio grade caps alone!). I've modded these to add a toggle switch selectable one ohm 25w resistor in series with the two woofers IF you choose to use (or have..) the 4 ohm version of the EPI 8" woofers wired in //. This allows the speakers to then be toggle switch selectable to be either ~4 ohm impedance or ~6-8 ohm impedance speakers. The 1st set I built this way seem to sound better (to me) with the one ohm resistor. EPI also used this resistor to boost impedance on the later versions of the 1000's when they switched over to having all four of its woofers wired in // (as opposed to the earlier models that had them in two sets of // woofers in series with each other...and no one ohm resistor for ~8 ohm impedance). I know...TMI! :lol:

add: Just as a WTF, here is a OmniMic response curve (including room acoustics..) of set #1 (oriented with the driver sides at 45 deg. to the listening plane) with the mic placed midway between them ~4' back:
M250_both.jpg
FR: 400 disk changer with PS Audio Digital Link III DAC; Technics SL-1100A TT. QED Quenx1 IC's from DAC & TT to Adcom GTP-602 preamp/Tuner. AudioQuest King Cobra IC's from preamp to M1.0t mk-II opt2. QED Silver Spirals 4M wires to EPI 1000’s.
LR: AudioEngine wireless link from family room preamp to Barcus-Berry 2002R Sonic Maximizer to GlowPower Zyxt IC's to Sunfire 300x2 to Nordost 6M bi-source wires to AOS 28" MDF spherical speakers using six 6.5" woofers and eight 1" dome tweeters symm. arranged around the surface.
SS system: CX-995V DVD to AV-634x 3-4 channel amp (center/rears) & M1.0t mk-II opt2(fronts).
Garage: 300 disk changer to Entech 202.5 DAC to MXR150 Receiver (pre) to TFM-42 to EPI 400 speakers.

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kingman
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Re: Elgrau's speaker project

Post by kingman » Thu Jan 01, 2015 9:31 am

WTF is that in the floor behind the speaker??? Looks like a plant limb or something?
In reality, it only matters what it sounds like to YOU!!!

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Re: Elgrau's speaker project

Post by BobSmi57 » Thu Jan 01, 2015 3:16 pm

Beautiful work on those speaker cabinets.

Bob

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Re: Elgrau's speaker project

Post by elgrau » Thu Jan 01, 2015 7:19 pm

Kingman wrote "WTF is that in the floor behind the speaker??? Looks like a plant limb or something?"

Just some pine branches from our tree that I was using to "spruce up" the sphere's for the holiday...must have fallen off! :lol:

Thanks, Bob!
FR: 400 disk changer with PS Audio Digital Link III DAC; Technics SL-1100A TT. QED Quenx1 IC's from DAC & TT to Adcom GTP-602 preamp/Tuner. AudioQuest King Cobra IC's from preamp to M1.0t mk-II opt2. QED Silver Spirals 4M wires to EPI 1000’s.
LR: AudioEngine wireless link from family room preamp to Barcus-Berry 2002R Sonic Maximizer to GlowPower Zyxt IC's to Sunfire 300x2 to Nordost 6M bi-source wires to AOS 28" MDF spherical speakers using six 6.5" woofers and eight 1" dome tweeters symm. arranged around the surface.
SS system: CX-995V DVD to AV-634x 3-4 channel amp (center/rears) & M1.0t mk-II opt2(fronts).
Garage: 300 disk changer to Entech 202.5 DAC to MXR150 Receiver (pre) to TFM-42 to EPI 400 speakers.

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Snoop65
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Re: Elgrau's speaker project

Post by Snoop65 » Thu Jan 01, 2015 9:03 pm

elgrau wrote:Kingman wrote "WTF is that in the floor behind the speaker??? Looks like a plant limb or something?"

Just some pine branches from our tree that I was using to "spruce up" the sphere's for the holiday...must have fallen off! :lol:

Thanks, Bob!
And I thought they were room treatments Ed. :lol:
CARVER LIGHTSTAR REFERENCE+SUNFIRE CLASSIC TUBE PREAMPLIFIER+JBL XPL200+MUSIC HALL MMF-9.1+GRADO REFERENCE MASTER 1+Cayin CDT-17a =WOW!!!!!!

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Re: Elgrau's speaker project

Post by OconeeOrange » Mon Jan 26, 2015 4:51 pm

Ed and I don't care much for each other (see old threads), but the guy is going overboard in his retirement. He has tools, instruments and knowledge way beyond me (maybe you)(think those guys on 'THE BIG BANG' TV show).
Ed has freaky energy and some of it has been funneled to building speakers.
He is not building for profit, but some will be for sale after some are passed to his kids.
He is "in" to be perfect.


More info is on I'm a Fucking Asshole as Ed can handle my personality with ease.
.

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