[Duke]

Two things that my bipolars are not:  Elegant, and phase-coherent.

Musician and longtime audio guru Jim Romeyn apparently saw potential in my Dream Makers and adapted some of the concepts to come up with his own unique, elegant, phase-coherent bipolar system:



On the back of the top enclosure is a rear-firing tweeter, and on the back of the bottom enclosure is a rear-firing woofer.  This way that second woofer is cancelling out the floor bounce notch and the baffle-step rolloff, is interacting with the room's boundaries quite a bit differently (which significantly smooths the bass), and is getting some extra boundary reinforcement to help with the low end.

Jim's system is called the "JR Modular Pro Monitor", and I haven't heard it yet but I am familiar with its mini-monitor predecessor, the ASA Pro Monitor, and it's the best speaker of it's size I've ever heard (Jim is selling his pair).   While the ASA Pro Monitor is too small to do the radiation pattern control thing that my big speakers do, it DOES get the power response right and disappears as the apparent sound source.  The designer juggled his tradeoffs in exactly the right way.  Jim has replicated that in his bipolars, which will do a significantly better job of recreating natural instrument and voice tone and disappearing as the sound source. 

From a technical standpoint, where Jim's bipolar system outperforms mine (and every other bipolar that I'm aware of) is in phase coherence.  The proprietary drivers he uses (he can't even tell me the source for one of them) have sufficient bandwidth to work well with first-order crossovers, and so his will have that little extra refinement, imaging, depth, and realism. 

I don't know if Jim did this on purpose or not, but putting the tweeter below the midwoofer is psychoacoustically correct.  You see, the ear/brain system tends to misjudge the height of a high frequency sound source to be higher up than it actually is.  Locating the high frequency source slightly below the midrange source works with, rather than against, this psychoacoustic phenomenon.

I'm honored that Jim saw potential in my offset bipolar configuration and used that as a springboard for his elegant, phase-coherent masterpiece. 

Finally, here's the link to the JR Modular Pro Monitors on Jim's website.

[jimdgoulding]

Masterpiece, that is high praise, indeed, and from the designer of whose Planetarium Beta's I've heard.  Explain for me, please, if what I might tailor make would or would not be of a benefit on the listening end of this speaker.

I'm not bein a wise ass here, ya'll, and I believe Duke knows that, and were it not for it being rear firing I might could figure for myself.  But, it does have a baffle and right angles.  And I can make moot what that translates to in the end.  Thanks, Duke.

[James Romeyn]

I am obligated, as a member of this mutual admiration team, to post the following. 

Even with three Duke-influenced bipolar monitors across the front in a Trinaural System, and even with two HPXO poles on the three main speakers (an active 80 Hz pole in the Trinaural Processor then a series capacitor between the processor output and the receiver input at about 200 Hz), with two Pioneer receivers employed, each receiver rated at 105Wrms per channel into the 8-Ohm nominal loads (one receiver powers the front output, the other receiver powers the rear output), Duke's Jazz Module played louder and cleaner with Berndt's then-200Wpc Jolida Music Envoy monos.  Not a little, but considerably. 

If size and cost enter the equation in any way, Duke owns the speaker universe for musical, enjoyable reproduction with absolutely no audible distortion at absolutely any level live and beyond, Ozzie Osbourne included.  This is not news to those familiar with Lynn Olson's attempt to find the clean SPL limit of Duke's speakers.

At Bill's house I would have guessed his room would overload before reaching the levels the system attained, but it didn't.   It was like the sound was a living organism and we were inside it.  Much fun. 

Kudos to Bill's custom 67 lb TT.  A lesser table would have went bonkers about 20 dB sooner.  One can only imagine what his current table is capable of.           

[James Romeyn]

Masterpiece, that is high praise, indeed, and from the designer of whose Planetarium Beta's I've heard.  Explain for me, please, if what I might tailor make would or would not be of a benefit on the listening end of this speaker.

I'm not bein a wise ass here, ya'll, and I believe Duke knows that, and were it not for it being rear firing I might could figure for myself.  But, it does have a baffle and right angles.  And I can make moot what that translates to in the end.  Thanks, Duke.

There are certain audible performance characteristics afforded only by Duke's "vertical offset bipolar" technology available by no other method known to me.  (Ditto Duke's subwoofer technology.)  I'd rather people just hear it for themselves than explain it.  Kind of like trying to explain the taste of rainbow trout caught from an ice cold Sierra Nevada river a few minutes earlier.  The words won't do it justice.  (I thought barbecued swordfish was unbeatable till the trout came along...) 

I really hope he brings the above technology to RMAF.     

[jhm731]

I don't know if Jim did this on purpose or not, but putting the tweeter below the midwoofer is psychoacoustically correct.  You see, the ear/brain system tends to misjudge the height of a high frequency sound source to be higher up than it actually is.  Locating the high frequency source slightly below the midrange source works with, rather than against, this psychoacoustic phenomenon.

In a time-coherent speaker like the GMA EOS with tweeters above the midwoofer, the image is located at the height of the woofer’s center after fine-tuning the tweeter’s position.No psychoacoustic phenomenon required.

[lowtech]

The proprietary drivers he uses...

They sure look like Dynavox/PE Dayton drivers.  If so, they are hardly proprietary.

[James Romeyn]

They sure look like Dynavox/PE Dayton drivers.  If so, they are hardly proprietary.

The drivers employed are not the brand mentioned above.  The drivers were made in Europe not China as per the brand mentioned above.  The drivers are not available new.  I'm not brave enough to sell $3k speakers with the brand of drivers mentioned above.  In late-1990 dollars the midbass was about $240ea, the dome $100ea. 

I understand the confusion.  The images aren't as clear as they could be. Readers can see a description of the cloned speaker (images too, they're for sale) at my website.  The images of the cloned French $7k/pr speaker are inconsistent with a speaker employing Asian parts of any kind.  Walter Swanbon of Fidelis was the last USA importer of the French speaker.