Hi,
At present there are only first generation CHR70s available in North America. The next build has just been completed and we're expecting inventory in about 3 weeks.
Bob
the capacitor does not only flatten the response, but also extends the bass, see the graph below (simulation done in LspCAD).
Attachments
OK people dMar-Kens are built just awaiting the chamfer on the fronts, I'll take a picture once the build is complete but before I finish them in veneer. These cabinets may be a tad large for the average dektop speaker if your into small, but to be honest they are not much larger than my 9L ported cabinets being used now anyway so I don't mind.... More to come....
Alright my dMar-Kens are sitting on my desk playing some Eva Cassidy. Soooo when I have a little spare time I'll do a review of my impressions and take a few pre veneer pictures for you. What I can tell you is that these little CHR-70's in this cabinet make some pretty impressive bottom end, much more than my 9L ported design does. They are quite a surprise, and friends who have heard them have asked me to turn the sub off so they can hear just the monitors.... hahaha, no sub in here boys LOL. So far I'm very impressed but the drivers in these need some breaking in yet so I'll do my review in a few days time permitting. Thanks for another great design Planet10 and Dave's crew, anyone thinking about purchasing plans for these don't hesitate they are a great design and much better than most everything I've heard in the 6 1/2" two way commercial arena so that says alot... More of a detailed review to follow.
Where can I find details of your 9l ported?
I lose track, is approx volume of dMar-Ken restricted info?
nope - for the CHR70, (dMar-Ken70) approx 9.2 liters, less volume of driver and bracing
Contact Dave for the drawings - the "majik" is in the details
Several years ago we built 2 or 3 (?) of the "Fostex factory" standard recommended BR designs for Fostex FE127E and FE167E, as well as a more conventional rectangular slot ported enclosure for the FE127 (Golden Ratio dimensions)
We heard quite convincingly that the combination of the high aspect ratio port slots, narrow and steeply chambered baffle, laminated wall panels, and driver brace contribute significantly to the superior performance of the "prime" design to standard ported/BR of the same net volume/tuning.
oh yes, Baltic Birch or superior grade high ply count plywoods are recommended
Thanks Chrisb, you certainly picked up on what I was thinking!
So the only way I can put my sceptism to bed, is to build one to planet10 spec, or wait and visit someone local who builds one.
But what if it sounds like the box I just built? Does that mean I got lucky and stumbled on a great design, or does it just mean I don't have very discerning hearing!
I dread to ask, but is the 'majik' measurable? Where are the plots of majik and non majik boxes?
So the only way I can put my sceptism to bed, is to build one to planet10 spec, or wait and visit someone local who builds one.
But what if it sounds like the box I just built? Does that mean I got lucky and stumbled on a great design, or does it just mean I don't have very discerning hearing!
I dread to ask, but is the 'majik' measurable? Where are the plots of majik and non majik boxes?
I guess the answer to 1) is yes, and 2) is - it would have to be the former as no frequent DIY pos(t)er would admit to the latter
geeze, I just confused myself
only by the smile on one's face
actually, I'm a bit surprised that I haven't heard from Ivor's lawyers about trademark infringement .... oh wait a sec, there's the doorbell
(that's a joke, 'cause they'd never ring the bell
) I just always liked the spelling of that word
I don't know if Dave has actually measured anything recently other than drivers raw T/S during the EnABL treatment and matching process
The Majik happens 40-50 dB down from the main signal.
Probably measurable using available tech, but not usually with the tools mear mortals can afford (lase vibrometry, laser interferometry, microFlown). And then comes the whole correlating measures to what is heard.
dave
The only measurement to date, that I think shows this 40 to 50 db down difference, can be viewed here.
Enable Tests
Note the difference in detail structure of the main resonant node's "nose". Note that the detail structure of the resonance is clearly depicted in one and pretty diffuse in the other.
We appear to be able to disperse these nodes too, but no objective data, other than from a Jordan JX 92, is yet available and it is buried in the original monster thread. No resonant node dispersion attempt was made on the 7 inch aluminum drivers that John K treated with a generic pattern set and tested, showing that improvement in downward dynamics Dave is claiming.
I am sure you will be able to hear it, though some folks take a bit of time to understand what is showing up, as it is not something different, just less confusion and a coherence down to the end of all information.
Bud
Enable Tests
Note the difference in detail structure of the main resonant node's "nose". Note that the detail structure of the resonance is clearly depicted in one and pretty diffuse in the other.
We appear to be able to disperse these nodes too, but no objective data, other than from a Jordan JX 92, is yet available and it is buried in the original monster thread. No resonant node dispersion attempt was made on the 7 inch aluminum drivers that John K treated with a generic pattern set and tested, showing that improvement in downward dynamics Dave is claiming.
I am sure you will be able to hear it, though some folks take a bit of time to understand what is showing up, as it is not something different, just less confusion and a coherence down to the end of all information.
Bud
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Independent of the "EnABL thing", and my earlier post might not have been clear enough on this point, but we definitely found in several iterations of different volumes of enclosures for the FE127E and FF85K that the "prime" or "milli" style enclosures that descended from the original mini-onken design for the CSS FR125 had sonic advantages over more conventional (i.e. single or even double) rounded port enclosures of equal internal volume and tuning frequency. Specifically more cleanly articulated and smoother extension on lowest couple of octaves, and the narrow profile and chamfered edges improve imaging - wrap some polka dots around the baffle and side panels, and these can pull quite a disappearing act.
Perhaps there are some measurements reflecting the objective effect of the resistive slot ports?
I agree. These are the most invisible speakers I have had in my system (Fe127eN and Fonken prime boxes). The bass is clear and detailed into the mid 30's with power that scales to that of the higher frequencies, rather than starting to compress as the spl goes up.
Quite startling to hear pipe organ music, coming out very clearly during the intervals between voice coil exiting the gap, from the 16 Hz signals. Very clear and clean and momentarily silent and back to very clear and clean. Heard in a 30 X 60 X 12 foot room while playing one of the pieces from Cantate Domino and filling the room with everything except wall shaking bass, from a pair of 4 inch drivers, at a Pacific NW Audio Society demo.
I think I was most impressed with the robust character of the system and the control over the driver that the resistive ports provided, under those extreme conditions.
Bud
OK let me clarify that my comparison is based on three different BR style boxes all running with first gen CHR-70 stock. My 9L ported/BR design is just a standard slot loaded design tuned to roughly 55Hz, 7L ported tuned to 70hz and the dMar-Ken. I never did any real posting of these designs because many have done it in the past and it seems redundant to post another CHR-70 BR design without it being a different beast altogether. With that being said the dMar-Ken for the CHR-70 seems to be much better braced and a much less resonant cabinet than the standard open box and brace design the BR generally allows. Not only is there an off center brace but the slot resistive ports are providing some pretty extreme rigidity themselves and the driver itself is coupled to the central brace. Another thing I have noticed so far is due to the ports being built the way they are in the deci style cabinet it acts somewhat like a constrained layer and eliminates most of the transfer of cabinet vibration that a standard BR box isn't privy to. I would say at this point that’s where the better definition and punch in the bottom end are coming from, more or less an inert cabinet and the resistive ports. I’ll elaborate later in my review…
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