[Duke]

Paul W, thank you very much!  I wasn't sure if they'd come across as "innovative" or "just wierd", and it sure is nice to see a positive initial reaction from you and others.

*  *  *  *

EthanH, while room size & acoustics play a role, the Rhythm Prisms do sound "full range" in my 15-by-18 foot open floorplan living room.  Now they don't make the room shudder on low synthesizer notes like the Swarm does, but they definitely have that "hits like a big woofer" thing going on. 

And I must confess that I do not understand why a big woofer has more subjective impact than a small woofer even if the latter looks better on paper.  It might have to do with thermal and mechanical compression in the small woofer, but that's just a guess. 

*  *  *  *

Hi launche, and thanks for your comments and support.   

Yeah I have long wanted to offer something in a lower price range that did most of the things I believe in.  The roots of the RP's go back to a bass guitar project I worked on last year.  In the bass guitar cabinet market, bang-for-the-buck is everything because a musician wants to put money into his instrument, not the cabinets he plays through.  Anyway I sent a prototype two-way bass cab to a bass player for beta-testing, and he liked what he heard.  He could tell the cab was fairly smooth and extended, so his band (which I guess would be called a rock-and-roll oldies cover band) tried it out on vocals.  Well they liked it so much in that role that they wanted a pair to use as portable vocal PA speakers in small venues that didn't have a decent house PA system.  So I started working on refining the crossover with the idea that this speaker needed to sound very smooth and clear on vocals, and from that effort the MRL (pronounced "Merle", stands for Multi-Role Loudspeaker) arose.  Thus the groundwork was in place for the Rhythm Prisms, which went through yet another generation of crossover refinement along the way.   

So that's how I ended up being able to do a more "down to earth" speaker. 

*  *  *  *

Hi Abby356,

Thanks for your kind words.

I don't yet know whether this will be the model that shows up at Lone Star; there are two more models of the same generation in the pipeline.  Interest on the part of people like you (and space limitations in my car) will determine what I bring.

*  *  *  *

On another forum someone asked if the Audio Kharma "Econowave" project inspired the Rhythm Prisms.  They both use the same waveguide-style horn, but the prosound projects described above were well underway before I knew about the Econowave project.  When researching options for the two-way bass guitar cab I found that horn on the Parts Express website and ordered one to measure, and it measured significantly better than anything else I'd tried in that size/price range.  I'm not using the same compression driver as the Econowave project, and don't know what its crossover looks like but there are probably some differences there as well.

That being said, Audio Kharma member Zilch initiated the Econowave project over a year before I'd even contemplated a prosound speaker, much less adapting such to a home audio application.  I tip my hat to him on recognizing the potential of that horn and initiating the Econowave design(s).  Unfortunately I've only skimmed a few pages of the Econowave mega-thread.

[jsaliga]

These look awesome Duke.  Congrats on bringing a high quality and affordable speaker to market.  I know you mentioned these speakers to me when I was trying to choose between the Jazz Modules and the custom Planetarium Alphas.  I ended up picking the Alphas and still believe they were the best choice for my particular needs.  But man these Rhythm Prisms look to be yet another compelling offering in your product lineup.

--Jerome

[Zilch]

Thank you, Duke, for acknowledging the efforts of the AudioKarma collaborative.

We are all working toward the same objectives, and I wish you great success with your new products....   

[Duke]

Hi Jerome, thanks for the thumbs-up!

The speakers you have on order are probably better to significantly better in just about every way... except maybe maximum SPL capability and of course price. 

*  *  *  *

Zilch, I really am impressed that you saw the potential of that JBL waveguide (I use the Pyle version with the metal threads).   I had probably seen it a dozen times on the Parts Express website but simply didn't pay any attention to it, until the time I was looking specifically for a 12" wide 90-degree-horizontal constant-directivity rectangular horn for a prosound project.  What was it that initially caught your attention about it? 

[Zilch]

Zilch, I really am impressed that you saw the potential of that JBL waveguide (I use the Pyle version with the metal threads).   I had probably seen it a dozen times on the Parts Express website but simply didn't pay any attention to it, until the time I was looking specifically for a 12" wide 90-degree-horizontal constant-directivity rectangular horn for a prosound project.  What was it that initially caught your attention about it?

I began attempting to DIY JBL 4430s in late 2004 with Progressive Transition waveguides.  By May, 2005, I had acquired some of them, and first had access to measurement capabilities.  The "discovery" is documented here, at Post #7:

http://www.audioheritage.org/vbulletin/showthread.php?t=6050

I completed several projects using them in '06 and '07, first mating them with inexpensive Selenium drivers in early '08, and AK's EconoWave collaborative was born in late February.  Earl measured them for us in May '08, and despite his scathing critique, it was clear we had a winning combo for entry-level DIY constant-directivity builds.

The AudioKarma mega-thread chronicles the fun we all have had (and are having) learning about and hands-on exploring the techology, with the help of many contributors, including your friend Wayne Parham, among others.... 

[cryoparts]

I want a pair!   

Bring a pair down, we'll do some listening!

Lee

Edit--have Lori bring a "smoke lamp"!

[cryoparts]

If you think there is fluff or don't agree with something, send Duke and e-mail or PM.  Don't muck up his product thread.

Indeed.   C'mon...can we keep this place friendly and have members of the trade (including myself) not talk s**t  about each other?  Duke is one of the "good guys", he and Lori are true gems of this industry, and they make a fine product.

Lee

[Duke]

Thanks for that link, Zilch.  Very interesting.  You know, Earl's speakers were 4430s before he started working on the Summas, and conceptually the Summas were an update of the 4430 concept.

In 2001, ignorant of the 4430s but with my little wheels a-turning, I first contacted Earl with a request for a 90-degree constant-directivity waveguide to be used with a 2" throat compression driver and crossed to a 15" woofer at about 1 kHz - conceptually pretty close to the 4430 (at the time I didn't think a 1" throat driver could go that low).

Anyway I find it interesting how the 4430 keeps coming up among people who value constant (or at least intelligently controlled) directivity.  Wayne Parham has a link to the AES paper describing the 4430 on his website.   I wouldn't be surprised if Bob Smith (SP Tech/Aether Audio) has a 4430 connection as well.

Here's the link to the paper on the 4430 hosted on Wayne's site, for anyone interested in what this "4430" is that I've been carrying on about:

http://www.pispeakers.com/AES_v31_n6_p408.pdf

*  *  *  *

Hi Lee, great to hear from you!  I sure appreciate the write-ups on my stuff from LSAF that you have on your website. 

Don't jump on this one just yet; there's two more related systems that are about to go public.  I'll try to get one of them posted this evening.

If you're serious about me bringing a pair down, shoot me an e-mail.  duke at audiokinesis dot com. 

Duke

[cryoparts]

*  *  *  *

Hi Lee, great to hear from you!  I sure appreciate the write-ups on my stuff from LSAF that you have on your website. 

Don't jump on this one just yet; there's two more related systems that are about to go public.  I'll try to get one of them posted this evening.

If you're serious about me bringing a pair down, shoot me an e-mail.  duke at audiokinesis dot com. 

Duke

I'll be in touch, after you announce the other products in the pipeline.

My pleasure, your speakers were the highlight of LSAF for me all three times I attended.

Peace,

Lee

[Duke]

Thanks, Lee.

Here's one of them.

And here's the other.

[James Romeyn]

All I can add is....GO DUKE!  Love the design!  Congratulations!  Can't wait to hear it.   

[Duke]

Someone sent me an e-mail asking specifically about "horn honk", and I thought it would be a good idea to post part of my reply here.

Horn honk is probably the great unspoken reservation people have upon first seeing the Rhythm Prisms, and I don't blame them a bit.  Most prosound horns have honk and/or harshness that makes them unpleasant to listen to, and many horn systems for home audio have the same problem to some extent.
 
Unfortunately my new generation of speakers hasn't yet been outside my living room at this point (early April 2010), so there are no independent assessments of their sound.  But there is a great deal of commentary on the sound of a well-respected DIY project that uses the same horn, and that provides relevant information.
 
On the AudioKarma website is a massive megathread and several related threads about a DIY project called the "econowave" (it uses an inexpensive waveguide-style horn with an inexpensive compression driver - hence the name).  The horn I use is the same one, though I didn't realize it was already quite popular in DIY circles when I first "discovered" it, while researching horns for a high-end bass guitar cabinet.  Here is a thread that gives a brief introduction; see in particular posts 3, 5, and 22:
 
http://audiokarma.org/forums/showthread.php?t=197859&highlight=econowave
 
Here is the AudioKarma megathread if you're so inclined.  Over ten thousand posts; I have not and do not intend to read it, though I have skimmed parts of it:
 
http://audiokarma.org/forums/showthread.php?t=150939
 
Now what is interesting about the econowave project is its massive popularity among DIYers who started out with a healthy anti-horn prejudice.  Here is a clickable list of econowave projects, click on the names and you can read comments by some of the builders:
 
http://audiokarma.org/forums/showpost.php?p=2260584&postcount=2409
 
Now let's get into why I think my speakers are significantly better that the best of the econowaves:  First, my crossover kung fu is mas macho; and second, I'm using a better compression driver.
 
In the curves that I've seen on the econowave thread, I can see evidence that the builders are either overlooking or not adequately dealing with a couple of issues.  Now in all fairness it took me several solid weeks with some pretty good test equipment to appreciate the consequence of these issues and figure out how to deal with them.  The econowave project is an excellent design, but I believe that my speakers using the same horn incorporate two refinements that are worthwhile. 
 
The compression driver I'm using is a fairly expensive unit that I had to import from Europe, though US distribution should be in place by now.  I believe it to be the finest driver of its type for this application, and I have tried all of the likely contenders or their equivalents.  My driver uses a polymer diaphragm and is smoother-sounding than the metal diaphragm drivers, and its internal geometry allows a better transition to the horn's relatively wide flare in the horizontal plane.  I will reveal its identity to my customers so that if I hit a moose one night they can get replacements if they ever blow a driver (unlikely).

I have not encountered any online commentary saying  "I heard the econowaves and they have horn honk" or words to that effect, and I looked hard to find anything like that before writing what you see above.  I'm not saying no such comment exists, but the trend is in the opposite direction:  The econowave continues winning over people who hate horns.  My claim is that my speakers that use the same horn are even further removed from having audible horn coloration.

[Russell Dawkins]

All I can add is....GO DUKE!  Love the design!  Congratulations!  Can't wait to hear it.   

+1! I really think you are on the right track, Duke, in concept and pricing.

[bluemike]

I've always been impressed with Duke's designs ..nothing has changed here

Good work

[James Romeyn]

DUKE!!!  I'm ten minutes south of you! (We'll, about "tree" minutes in an F-15 minus afterburner, longer by Mazda).  Call me and let me hear them!

PS: I'll bring the flat top you heard Valentine's Day, and a guitar preamp, whose output will go into your amp to drive the new Rhythm Prism.  How will that be for a test to detect horn honk?     

Sleepless in Providence Utah... 

[pardales]

Could you say a little more about what is a proper set-up for these speakers? Can they be placed near wall?

[jimdgoulding]

This is a pretty old thread, huh.  They made it to LSAF but I don't think they made it back.  Think Duke sold em to a local.  Bet he is a happy cat, too.  The customer, I mean.  Sounded awesome to me and I'm not fond of any speaker that calls attention to itself. 

[Duke]

Could you say a little more about what is a proper set-up for these speakers? Can they be placed near wall?

Near-wall placement works fine, either near the sidewalls or up against the wall behind the speakers.  At Lone Star, I had the Rhythm Prisms about five or six inches out from the wall behind them, and the left-hand speaker was about eighteen inches in from the side wall as I recall.   Here's a picture:

http://www.audiocircle.com/index.php?topic=80966.msg781316#msg781316

We were getting a lot of bass reinforcement, as is typical of hotel rooms, so I plugged the top port on one speaker and the bottom port on the other.  This lowered the tuning frequency to about 26 Hz, and introduced some vertical staggering of the low bass sources (desirable from the standpoint of bass smoothness).   

Comments were quite positive; here are a few that ended up online (inserted 6-10-10):
 
"I was most impressed with the [AudioKinesis Rhythm Prism] speakers I heard today.  They had an open and airy sound and really great range that seemed to flow effortlessly.  I'm not the most critical listener but first impressions are usually correct and you really hit it out of the park.  Fantastic stuff and good luck to you and your team."
 
"Audio Kinesis in house made speakers... were for me making some of the very best sound at the show. Human voices were so amazingly real, and the whole set up just had a really musical vibe if you will to the whole thing. Was happy to have been lucky enough to have experienced that room."
 
"Duke's speakers - he'll need to tell about this new model - were sweet and delicate and lithe on Simon and Garfunkle Live in Central Park and as dynamic, clean and hugely emotional on Hugh Masekela's Stimela [the Train Song] as anytime I've heard that tune with the little Lighter Note preamp and, get this, powered by the amplifier in a small NAD integrated.  Seriously, they played both these live recordings like they were made for them with generous sized imagery and space."
 
See also OzarkTom's post on page 3 of this thread.

[ttan98]

Duke,

Nice looking(color is a little old fashion) and is very well priced speakers. I have no doubt it will sound good as well esp. one designed from you.

I have a similar horn that you use in this model, can you give me a hint(brand and model) what 12" driver you use?

[Duke]

can you give me a hint (brand and model) what 12" driver you use?

That's the Eminence Kappalite 3012LF.  Not the easiest to work with as you'll see from the factory curve, but its dynamic capability is pretty awesome, both thermally and mechanically.  It can move more air than most 15" woofers.  And at the other end of the scale - that is, at low volume levels - it is still articulate.  In fact one of the first people to visit my room at Lone Star commented specifically on how the system sounded good at the relatively low level it was playing.  He had an SPL meter, and clocked it at upper 70's as I recall. 

On another note, believe it or not I actually got positive comments on how they look from women who came into the room at Lone Star.   Now presumably these were the wives of audiophiles and therefore had seen much worse, but still that was a nice surprise.