[denverdoc]

Not that I have been particularly good boy this year, but for XMAS I am buying myself (as noone else, including Santa, seems predisposed to the task) the DEQX pre with bal out option.

A long and torturous path has led me to down the DIY path, and am trying to find the least expensive path to audio nirvana that doesn't incur brain damage.

Figure I need a decent transport, the DEQX, some digital(?) amps, and of course speakers. What I have in mind is: IB crawl space dwelling subwoofs (16L Vd), adire extremis 6.5 midbass x10/side in dipole Line array, and B & G 75" ribbons. All told maybe 7k for the drivers/DEQX which will eliminate the need for any passive xo components.

Premise of the project is: that energy storage both in room and in cabinets is the arch enemy of good sound repro, that the digital domain is the best place to implement xovers and EQ, and that megabuck amps, wires, CDP's, etc are  for the most part misguided tomfoolery. If it (supposed difference) can't be measured, or reliably ID'ed in casual blind AB testing, ain't worth it to me, blue laser biasing notwithstanding.

Anyway, would love to hear your guys thoughts on transports and digital amps --I'm talking not EAR ICE type digital, thinking more along the lines of Tex Instruments.

Now this may be nuts, but after a toroid shorted in one of my big Classe M-1000 monoblocks and Edge Electronics quoted me 500 to replace, started to wonder whether an amp like those used in car stereos could be done in class D using a stack of car batteries which could be stuffed down in the crawl space. For the price of that toroid, I  could have several hundred amps of clean current to kick start my morning! STONES EOMS-Sweet Virginia at 120 dB peaks to get the synapses collaborating.

And of course, if any of you guys are curious about what properly implemented digital eq can do for your systems, willing to make the rounds, and get to know you all.

You know as i count my many blessings today, I love Colorado--lived all over the west: California (hottest women), Nevada (cheap entertainment), Utah (best skiing), Colo, best all arounder!
John

[mgalusha]

John,

You mention using an IB sub. Since you live in Denver had you ever heard Thomas W's. IB sub? info here

When he really cranks it up it feels like the whole house moves.

I for one would like to hear your setup when you get it all done.

mike

[denverdoc]

In fact fortuitous contact with Thomas and hearing how articulate, deep, and potent his system went left me no alternative but to go IB. Soon I will be a card carrying member, and Thomas tells me the initiation rites to IB ranks will at least leave me breathing. But i MUST HEAR the left hand of darkness.

Realistically, esp as a dying cat peed all over the inside of 5K monoblock, destroyng the transformer, that even Edge elec cannot seem to get a replacement for, and Classe is not helping in the sourcing(bah humbug to them)  looking at mid Feb. But I want to hear what you all have all assembeled and if possible, get a take on improvements that DEQX might make to various systems,
Cheers,
J

[mgalusha]

John,

You're welcome to come by for a listen if you like. It would be interesting to hear what the DEQX can do. I live on the south end of town, near the DTC and Park Meadows mall.  I suspect some of the other Denver area members would like you to bring your new toy over to their places as well. Shoot me a PM and we can figure out a date and time.

If you can get the specs for the transformer, Victoria Magnetics winds custom transformers for a very reasonable price. They might be able to help you out. I had them wind me a set and was very pleased with the results. www.victoriamagnetics.com

Mike

[denverdoc]

Mike,

Thanks for the tip--gonna call Edge on Monday for an update and suggest that--hell now that i think about it--they have the core and wire--maybe I can find a solvent to attack the epoxy, measure the wire  and rewind it myself!
J

[ekovalsky]

Not that I have been particularly good boy this year, but for XMAS I am buying myself (as noone else, including Santa, seems predisposed to the task) the DEQX pre with bal out option.

A long and torturous path has led me to down the DIY path, and am trying to find the least expensive path to audio nirvana that doesn't incur brain damage.

Figure I need a decent transport, the DEQX, some digital(?) amps, and of course speakers. What I have in mind is: IB crawl space dwelling subwoofs (16L Vd), adire e ...

Sounds like an awesome plan.

I just migrated from the very expensive dCs "stack" and JRDG 302/4 (ICEpower) amp to a much less costly setup using a Meridian transport and TacT RCS 2.2X and two S2150 (Tex Inst Equi-bit) amps.  The Tex Inst amps seem to compare very favorably to the ICEpower and take a digital input to boot -- no external DAC needed !  And no volume control is needed since attenuation is accomplished via reducing voltage on the power supply rails.  Basically the S2150 amp is a very good DAC with ultra high current output, enough to drive loudspeakers directly!

[JoshK]

Hey Denverdoc,

Glad to hear you got it!  Sounds like your system is going to be very cool.  If I ever make it out to denver I am going to have to invite myself over.    

I like your choice of drivers.  Still thinking of doing the foam baffle?  I think you may have something there the more i have thought of it.  On Linkwitz labs' website they show rear support for bipole arrangements and it looks like it would work for your case.  

I have two projects to build before I tackle something similar.  After hearing Frank's transaural system though I may just do something drastic!

[denverdoc]

Hey Josh and Eric,

Thanks for the encouragement . Josh, since we last corresponded a few weeks ago, everything snapped into focus after a visit to Thomas W's (IB maven) home. I'd been flailing on the bass issue for some time, but after hearing the awesome reach and articulation of Thomas's system, deciding to run IB from mid teens on up to 60-70Hz instead of dipole subwoofs, the rest just fell into place. Now Thomas tells me there might be issues with the Adire Extremis drivers. I have no details yet what these might be, only know that they still haven't shipped the pre-orders (next week has been a long time coming and is still the estimate) and some specs or the FR has changed. My hope is that the distortion specs and Vd haven't changed substantially, the DEQX can likely cover any minor FR anomalies.

By all means stop on by--figured you'd be in Aspen in January competing in the extreme winter sports, or at least spectating.  

[denverdoc]

Josh,

Almost forgot, yes re the foam baffle!  Biggest problem has been finding a supplier who is willing to dink with a one off order--material I'm  favoring is med density polyurethane (6 to 8 #/ft^3) which can be cut with a hot wire so long as you don't breathe the highly toxic fumes and is relatively machineable. For comparison, blue styrofoam is limited to about 1/2 this density. Assuming the dims to be about 8'x2', mass will be about 35 lbs per panel ignoring the cutouts and the epoxy laminates. So not quite as light as I'd hoped but considering the stiffness is comparable to maybe an inch of aluminum, not bad.

 The main slab will be 2 to 3 inches thick, then a few mm laminated on that to bring the drivers flush. The mid bass drivers will be epoxied to a vertical carbon fiber beam in back which will be sunk into  the stand, and rest lightly against the baffle just enough to provide an acoustic seal. Carbon fiber cloth will be used as the outer plies of the sandwich.

What I haven't figured out--is it better to have all of the array drivers equidistant from the baffle edges, or maybe tapered like a shield--certainly enhance the sex appeal of the design, ie truncated diamond shape.

Hell I can't even figure out if the edge diffraction front and back sources being so close and out of phase will cancel each other out and render the issue moot. My guess is no, as some folks have gone to considerable trouble to test various shapes w & w/o wings, and report significant differences, but as far as I know the panel thickness was constant.

With foam a thought i had is since it can be contoured in the z dimension fairly easily, then  the lateral components of the front and back waves meet at a point, which unless I'm having a brain fart would seem to me  provide for complete cancellation of edge diffraction sources irrespective of frequency. With wings not so simple.

[dwk]

Hey Doc, wWe gotta talk!

I've been walking a very similar path the last many years, playing around with digital/FIR xovers and eq similar to what the DEQX does using Linux/BruteFIR. My path has included both 'ribbons' (Carver 60" in my case) and battery-powered TI Equibit amps (I have a battery-powered XR-25, plus a stock XR25 and an XR10).  The ribbons might need a bit more power than they have available, but IMHO running digital out from the DEQX into battery-powered Panny receivers for the midbass and ribbons might well be a very very nice approach.

I don't really have a system together at the moment, as I'm completely revamping my speaker decisions due to a room too small for full-range dipoles, but I'd love to have a chance to experience the DEQX.

Where are you in your speaker cycle? I have some baffles (just cheap 3/4" birch ply) with the Carver Ribbons and 4 Stryke SA071 midbass per side sitting unused at the moment.  They might be a valuable tool in experimenting. IMHO the Carvers need a tweeter to really achieve world-class status, but sound better than decent even without one.

I'm in central Denver, just east of City Park/Museum/Zoo.

[denverdoc]

DWK,
Indeed we do need to talk. Today I'm picking up the 75 inch B&G ribbons which I believe are quite similar to the carvers. Bad news is I wont have the DEQX until nearly end of month.  Hoping the Adire 6.5 inchers (extremis)are as good as their advance press, but waiting to hear back from Jon Marsh on these. I think your ideas about amps are very interesting, but as the refurb DEQX I am buying has the bal out options and no digital out, would have to be hybrid if i'm gonna go digital--speaking of which the Tripath Godzilla chip set looks very interesting. Fior about 300, can buy the developers board with something like 200 WPC x 2 with a +/-50 volt source for the rails--I'm not much of a diy'er but to me this just screams for some kind of battery implementation.

I just sold my big infinity's which for the moment means I have just my Newform 645's to play with. Thomas W is gonna loan me a pair of baffles with a bunch of 7 inch drivers that he could never get to sound right; once I get the DEQX I will play with those and the B&G ribbons while waiting to see how the Adire drivers shake out. If those have the low distortion and big Vd's claimed will buy 20 of them! But I'm still open to using scan speak or seas mid bass units and a host of others--just want to be able to get the array down to 70 Hz w/o limiting, thats where the pair of big 18 inch avalanche IB (crawl space) woofers will take over duties. yea, love to chat, etc!
John
(off to get the ribbons!!)