DCAudioDIY.com

Jim,

First of all, thank you for having me over last night. Second, kudos for you in what you have put together. Your rig took me away someplace. I NEVER thought that horn/coaxial speakers, SS amps and enormous boxes could sound so smooth, relaxed, effortless, delicate, revealing, natural, and resonance free! The level of clarity (low distortion?) was amazing. I listened to cuts I've probably heard 50 times or more. I heard things CLEARLY that I didn't know were there. That system took me into the room with performers in a way I've only ever heard before at Charlie's.

Holy cow! I am amazed! The craftsmanship of your equipment stand is superb, it looks beautiful.

We probably listened at less than one watt. That was simply a joy to hear in every way.

Thanks so much for your advice, knowledge, help and participating in our group.

You have the best ears of anyone I know. Your system reflects what you are able to do with that information.

Thanks go out to you, Charlie, David McGown, Roscoe and so many others in the group, for helping me learn and enjoy this hobby.

I can't wait to get back to your place, Jim!

Stuart

Details and pics would be nice!

Roscoe

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I can explain it to you, but I can’t understand it for you.

Don't know all the details. Not sure how much Jim wants out there. Didn't take pictures.

But: Urei mid-field studio monitors with JBL coaxial horns and helper woofers, combined with Jim's DIY subs. All SS amplification, Chameleon line stage using 12AU7 (at the time I heard it). PS Audio DAC, Sonore Signature Rendu renderer, NAS, Special cabling from The Mapleshade folks, Magnavox player for discs, S/PDIF out to DAC. LP filter

THIS rig is why people SHOULD love horns! WOW!

I was told, repeatedly, that this system was good. It's not that a) I didn't believe the wise man who told me so, nor that I didn't listen. My own prejudice against horns and "studio monitors" kept telling me: eh, well someday I'll get there.

So glad I made the time. As some are wont to say "It was a teachable moment".

The attached picture LOOKS like the one we listened to. Not sure. Bet Jim is.

There's three different versions of that 15" co-axial driver. The earliest on is based on the Altec 604K, the middle one is a JBL compression driver on a woofer by another company who's name escapes me right now, and the final version which is all JBL. The middle version is reputed to be the best, but who knows. We had a pair of the middle version on open baffles at CAF a few years ago, but not with the correct time-aligned crossover, and on an open baffle they really needed a current source amp to get any bass. I'm going to be trying those again in the next few weeks, I have all the parts to make the correct crossover, and I'll be bi-amp them with a sub. One of four new open baffle designs I plan to try in the next few weeks. I'll also be trying 12" co-axials from Tannoy & B&C...

Roscoe

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I can explain it to you, but I can’t understand it for you.

The one that Jim has uses the driver which was designed as an organ speaker. Jim says it's ruler flat from 80Hz to 1.2kHz. Absolutely believable as the sound of an acoustic guitar was reproduced with full body and harmonics. REAL.

Horns when done right as Jim has are great in a small or medium sized room because of the controlled radiation pattern. A lot of the early reflections are eliminated resulting in a lot of direct sound getting to the listener. The direct to reflected ration is great. Most people concentrate on the high sensitivity that results from the controlled directivity and the acoustic transformer effect of the compression driver coupled to the horn. However, I think the best part is the controlled directivity resulting in a much lower amount of early reflections.

Tom

They sound better than they look.

Speakers are the 813C model, plus DIY 18" 2245h subs. I think the "C" model sounds the most natural. As Stuart mentioned, the E-145 mid woofer is the magic, I believe. All 4 boxes are ported. The UREIs were specifically designed for soffit mounting in studios. The infinite baffle, and generally mounted "helper woofer" near the wall/ceiling intersection gave them great bass response. Soffit mounting wasn't an option here, so I built the 8 cubic foot subs for below 70hz. When these speakers were popular, most studios EQed the heck out of the helper also. The studio where I first heard them ("A" version) was famous for disco recordings and they did just that. All the drivers are NOS, and I just replaced the aftermarket diaphragms I was trying out with originals. That eliminated some ringing that was evident, particularly with piano. The system is about 100db efficient. I have one of Dave Berning's 300b amps, and it'll push you out of the room with 6 watts.

It's essentially a nearfield set up. Unlike newer models like the M2 that have great off axis response, these do not, so the sweet spot is small. Tom's right on concerning the controlled directivity and lack of reflections. The downside is they don't achieve a realistic sense of space like a boxless or dipole speaker can. Trade offs.

There is a plan coming together to build narrow baffled floor standing cabinets. That will give me placement options. As you can see, I only have 1 right now. That would also qualify them for use at Capfest!

This is a good month for anybody interested in hearing them. My wife is traveling. Late afternoon/evenings or rainy days are my only availability right now, however. It's my busy work season. I'm in Annapolis.

I believe there may have been 4 models, but haven't Googled it. The 1st 2 were 604 based, and the only difference may have been the horn shape and crossover changes. 811/813/815, then 811A/813A/815A, then B, then C. The B model used a Pass woofer and JBL compression driver for the coax, and an Eminence Helper (813B,815B), The C is all JBL drivers after they purchased UREI.

I have heard Jim's system, and it is terrific. Jim's own analysis is spot on, small sweet spot and the sense of space is diminished, but WOW. Dynamically exciting, transparent/detailed, very deep low bass with visceral impact, nice tone & body, fun to listen to. Just close your eyes to eliminate the dominating size of the speakers, relax, and enjoy the music. A visit to jim's is now more about what music to bring/play, and what he will surprise you with, the equipment is secondary to just listening to music and having fun. Kudos to Jim for assembling such an unusual system, it shouldn't sound as good as it does, just goes to show, don't judge a system by the components, you have to hear it, and hearing Jim's is a delight.