Ardent Speaker Camp

[JonMarsh]

Two rooms at my house will be setup for auditions.

And the tickets will be cheaper than for RMAF, too, I hear, though not the accomodation packages. :W

[Dave Bullet]

I have a question about making the baffle so thick it. The centre of gravity (unless the back is equally thick) will transfer to the front (weight bias). Will that make the baffle prone to vibration since the front legs / spikes will become "more of" a pivot?

[Jed]

The 10 degree tilt of the baffle should shift the center back quite a bit I would think. I don't think Jon has to worry too much about a vibrating baffle with the mass and multiple densities he used.

[JonMarsh]

Yeah, what Jed says... and then some! :W

I use a triangulated three point setup, and this kind of construction has been very stable. The existing computer drawing screen shot above has three front panel and back axis vertical to the workplane axis, as it's easy to work with on a CAD basis while generating it- I'll prepare a render soon with it in the "normal" laid back/sitting on the floor position and some "drivers" stuffed into it.

I'm late getting to that, but I'm more concerned with the nitty gritty for now than generating pretty renderings. :W

[JonMarsh]

Jon,

Wonderful speaker building! :T

Kris

Thanks, Kris!

Just pushing the boundaries a little, going where no sensible DIY'er has gone before (in this neck of the woods)...

Oops, wrong mythos.

Anyway, it is exciting, though some moments in the last couple of weeks have been a bit nerve wracking, too.

[ColoradoTom]

Well, we'll have to see- I think you're moving faster than I am- it's looking like I'll have more business travel, including two weekends, than I expected this month- I'm crossing my fingers that DOESN'T pan out! :W

This next weekend I'm shooting to get all the piece parts milled and ready for assembly, but the weekend following that is one I may have to travel, and the one after that, too. That will limit my progress, in all likelihood, unless I can sneak some work in during the week. We'll have to see...

BTW, we'll expect pictures of the bedroom set if that's OK- I enjoy seeing your work!

~Jon

Yup... seems like whenever I get on a roll something comes up to slow things down. I don't have to deal with travel, but my two teenagers are like a "blackhole" with my free time (although I not complaining). I'll post some pictures as I move along..... I'm keeping a build log to give to my daughter when the set is done as proof that I actually did build it for anyone that questions her.

Tom

[ColoradoTom]

The 10 degree tilt of the baffle should shift the center back quite a bit I would think. I don't think Jon has to worry too much about a vibrating baffle with the mass and multiple densities he used.

I can confirm both Jed and Jon's statements as I built a pair of the "smaller" version and there is no issues with weight distribution.... unless you're trying to lift them. :rofl: It takes a good amount of push to get the back to lift off the ground and I'm sure the new design will be similar.

Tom

[JonMarsh]

I can confirm both Jed and Jon's statements as I built a pair of the "smaller" version and there is no issues with weight distribution.... unless you're trying to lift them. :rofl: It takes a good amount of push to get the back to lift off the ground and I'm sure the new design will be similar.

Tom

well, you know, we could always add some kind of plitron or equitech thingie to the back, like the ones I used for helping out clamping some panels, if folks think they're a little light in the back...




It'll be a lot clear with a better computer render or pictures of the final item. You see, they'll look a bit like these: (thanks and a tip of the hat to CraigJ)

[JonMarsh]

Sounds like you've got it under control... When I first did mine it was a little scary with all that exposed blade staring at me. With the new Festool plunge saw I have I can do these very accuratly using its supplied guide and with the saw tilted to 45 degrees. I get a depth of a little over 2 inches with each cut and the final results are as good or better than I can do with the table saw but with a much higher degree of safety.

Things are looking really nice. Hope they sound as good as they are looking!!

Tom

Well, if all goes as planned, you can listen and decide for yourself the first week in October- I hope to drive out with a complete system with these to "demo" at Tom's while RMAF is in gear- will probably get out a few days early, and leave a few days afterwards. I understand Chuck will be out, too, and usually we've met up with some other internet audio acquaintances.

[chasw98]

Hopefully life will go as planned! And you will be on your way to Denver in Sept/Oct!

When you say a complete system, does that mean things like multi thousand dollar speaker cables, expensive low wattage integrated amplifiers built by long time friends, source equipment with dacs to die for? Or just hook it up to Tom's spare Adcoms with an iPod?

I will be there.

[ThomasW]

When you say a complete system, does that mean things like multi thousand dollar speaker cables, expensive low wattage integrated amplifiers built by long time friends, source equipment with dacs to die for?

Actually yes that is the plan... 8O

[CraigJ]

I can just see Doc Emmett Brown loading everything up in this and crossing the Rocky Mountains :rofl:



Craig

[Hdale85]

Except he owns an NSX........not much storage in those either.

[ThomasW]

His 'utility' vehicle is an Element....

[JonMarsh]

I can just see Doc Emmett Brown loading everything up in this and crossing the Rocky Mountains :rofl:



Craig

I like that trailer!

I could get the source equipment and some cables in the NSX, but not much else- forget clothes even!

But as Thomas notes, my utility vehicle is a Honda Element; with the back seats out, plenty of room for speakers, and lots of weird equipment.

But I like that trailer.... :W

[fjhuerta]

The NSX is one of those cars I wish I could drive at least once in my life.

That and a 911 RSR.

[CraigJ]

Except he owns an NSX........not much storage in those either.

Great Scott! It was a "Doc Emmett Brown", Back to The Future joke. :W

[Hdale85]

Yes I know NSX's really aren't to terribly expensive anymore at least the semi older ones. But certainly a nice one to own although if I got one I'd really want like a 2k+ more then likely even the very last year they were made.

[JonMarsh]

H
Or just hook it up to Tom's spare Adcoms with an iPod?

The thought of that makes icewater run in my veins... even if you had one of these....




And I do have Apple lossless on my iPods...

[---k---]

similar to the one being built by chasw98 come first.

How come we never see posts and pictures of what you and Chuck are building?

[dsrviola]

Accuton C95

Maestro Curmudgeon,

Have you worked with the C95 before? One of the smoothest Accutons out there, but not to my liking when it comes to handling midrange frequencies.

[JonMarsh]

How come we never see posts and pictures of what you and Chuck are building?

Chuck's picks are in the "New Home for RD's" thread, though the project has seemed to turn into a Neo BG project, not an RD project. :W

[chasw98]

The thought of that makes icewater run in my veins... even if you had one of these....

And I do have Apple lossless on my iPods...

Just performing a required sanity check!

And if the thought of that makes icewater run in your veins, what is running through Evil Twin's system? Some exotic derivitave of low temperature electrothermal vaporization inductively coupled plasma mass spectrometry after synergistic extraction with dimethylheptyl methyl phosphate and 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5?

[cjd]

Hey now... though not a huge fan of Apple's lossless (proprietary stuff sucks... not that my open format is exactly widely supported by the folks that support proprietary but make half the hardware...) I do most of my listening through a squeezebox (Duet attached to an external DAC in my main system, SB3 in the secondary system, Boom in the bedroom which may soon be getting a sub/sat setup [this is where I was going to do some funky many-RS100 driver setup but that's turned out to have box size issues for what I wanted])...

Anyhow, I've compared directly against the CD and am not sure I can complain - digital is digital, and the problems that exist therein don't go away moving to a CD.

Some day I'll get the TT running.

[Evil Twin]

Just performing a required sanity check!

And if the thought of that makes icewater run in your veins, what is running through Evil Twin's system? Some exotic derivitave of low temperature electrothermal vaporization inductively coupled plasma mass spectrometry after synergistic extraction with dimethylheptyl methyl phosphate and 1-phenyl-3-methyl-4-benzoyl-pyrazalone-5?

This is MOST disturbing- obviously, though I thought I completely eliminated the last infestation of Rebel spies, clearly you have acquired closely held information about our innermost system configuration out there in the Floridian Sector, something I would not have believed possible.

Marsh, I don't want excuses this time, I want the heads of those rebel spies! Pray you are more successful in your efforts this time, lest you join your former associate Captain Needa.

[JonMarsh]

Hey now... though not a huge fan of Apple's lossless (proprietary stuff sucks... not that my open format is exactly widely supported by the folks that support proprietary but make half the hardware...) I do most of my listening through a squeezebox (Duet attached to an external DAC in my main system, SB3 in the secondary system, Boom in the bedroom which may soon be getting a sub/sat setup [this is where I was going to do some funky many-RS100 driver setup but that's turned out to have box size issues for what I wanted])...

Anyhow, I've compared directly against the CD and am not sure I can complain - digital is digital, and the problems that exist therein don't go away moving to a CD.

Some day I'll get the TT running.

Actually, I was trying to more make a statement about the Adcom amplifiers than the iPod. Analog output of iPods is rather variable depending on the model and the DAC used in it; when they shifted away from Wolfson and went to Crystal Semiconductor, things went down hill with the iPod classic, IMO. The only solution that might be somewhat usable for "quality" is that Wadia dock, because it extracts the digital data before the DAC, and creates an SPDIF stream.

Now, computer music sources can be pretty good these days with the right hardware and software. While not ideal, or my "final setup", I'm running a Mac Mini into a PS Audio DLIII on the USB input, which is only adaptive mode, not asynchronous, and you have to use Asynchronous upsampling (which the DLIII does rather well) to get low effective jitter and the best sound.

In this mode, my ripped CD collection (which includes many CD layers from hybrid SACD's) has moved a very significant step up in reproduction quality compared with say, a $3500 Sony SACD player. It rivals a recent SA-11 Marantz that I own; a different presentation, better in some areas and ways, not quite as good in some others, but it's not wearing out the read laser on the Marantz every time I want to play a CD. And the accessibility factor is remarkable after dealing with disks for so many years. In general, the effect is as if all my CD's have been replaced with new re-mastered versions that sound substantially more dynamic and analog- and the really good CD's are now bordering on stunning. It also works pretty well with inputs from my Marantz and Cambridge Audio 640C, which has fairly low jitter on the SPDIF outputs.

So, progress is being made. The next step I figure is a better data clocking and a DAC with apodizing minimum phase filters, like the PS Audio Perfect Wave or the Ayre QB-9.

[ThomasW]

How come we never see posts and pictures of what you and Chuck are building?

Chuck is posting pics of his progress. Although I have all the drivers, I haven't started working on my version of the line arrays. I'm continuing to problem solve aspects of the black Whisper dipoles. And getting ready to transition from the prototypes to working on the final design.. When that occurs a build thread with lots of pics will be started.

Maestro Curmudgeon,

Have you worked with the C95 before? One of the smoothest Accutons out there, but not to my liking when it comes to handling midrange frequencies.

Listening to C95's in the Isiris design as I type. I have no major complaints against them...The Isiris is a bit of a 'Franken-speaker (as in Frankenstein, not Al Franken .... ) and I've never been completely satisfied with the Isiris' performance, but think that's primarily a function of the design needing a dipole tweeter.

[---k---]

Chuck is posting pics of his progress. Although I have all the drivers, I haven't started working on my version of the line arrays. I'm continuing to problem solve aspects of the black Whisper dipoles. And getting ready to transition from the prototypes to working on the final design.. When that occurs a build thread with lots of pics will be started.

Thanks to you and Jon for pointing me there. I haven't been following every thread recently, just not enough time. My bad. But, I had to razz you two a little.

[Hdale85]

I have an HTPC that runs into a DIY DAC (Twisted Pear) and then goes into my amp via balanced connections. The DAC is a dual mono with an outboard reclock and jitter reduction and it sounds fantastic. I haven't really heard any CD player best it but I also have not heard any real high end stuff either. I love the accessibility factor though just as you say Jon.

[cjd]

I'm running one of the original Beta Opus DAC's from Twisted Pear - Wolfson chip, balanced signal out. Really tempted by some of their new stuff but I have other places to put the cash (like a proper pre-amp) right now...

[Hdale85]

Yeah eventually I plan on doing one of their new Buffalo 32's with the AC-1 LCD/Remote/Controller unit as a 2 channel preamp sort of thing.

[Hank]

Jon wrote:

though the project has seemed to turn into a Neo BG project, not an RD project.

I have just about decided on RD50's to go with my Peerless mid-woofs, and no tweets - it will be a two-way. Let the flames begin for my not doing a three-way like Chuck. So, I'll raise a tequila toast to the lack of frequencies that I couldn't hear if they were there. I'll order the Rd's probably by Summer's end. Yeah, I know, I'm slow as Christmas - too many high-level technical work projects. PhD's and this lowly Texas Sourcing Manager - a mixture guaranteed to spin off projects like extra valence electrons.

BTW Chuck, have you decided on a finish? laminate? veneer?

Jon: Ipods?? losless??? I'm tempted to insert one of your classic, "Where did we go wrong in raising you?" lines.

[JonMarsh]

Jon wrote:

I have just about decided on RD50's to go with my Peerless mid-woofs, and no tweets - it will be a two-way. Let the flames begin for my not doing a three-way like Chuck. So, I'll raise a tequila toast to the lack of frequencies that I couldn't hear if they were there. I'll order the Rd's probably by Summer's end. Yeah, I know, I'm slow as Christmas - too many high-level technical work projects. PhD's and this lowly Texas Sourcing Manager - a mixture guaranteed to spin off projects like extra valence electrons.

BTW Chuck, have you decided on a finish? laminate? veneer?

Jon: Ipods?? losless??? I'm tempted to insert one of your classic, "Where did we go wrong in raising you?" lines.

Hey, that's just for listening with headphones.... these days it's a Mac Mini with USB to the DLIII DAC, and it spanks most of the CD/SACD players I've owned. If I had more pennies in my bank account, I'd probably pop for an Ayre QB-9, but it's just not in the cards right now.

yeah, the "busy" factor in life is a you know what, rhymes with "itch". Just think how I feel- I have a set of NOS RD50's in the cupboards now for about 5 years.... and some matching Fountek Ribbons. And I'm just trying to find time to build a little 3 way floor stander. :W

You really ought to see if you can't tear yourself away and get out to Denver for RMAF... think of the stories you could tell afterwards, the people you could corrupt with premium tequillas... it boggles the mind! :B

[Hank]

think of the stories you could tell afterwards, the people you could corrupt with premium tequillas... it boggles the mind!

hmmmm... :idea:

[JonMarsh]

Well, while you're thinking, you can peruse this...



CAD work isn't completely finished,but it's getting close, and I'll be doing more cabinet piece work this Saturday at least. I'd like to say I'll be gluing a box or two together, but I know better than to be too optimistic at this point. If I get the sides completely finished cut and routed, and the braces cut, drilled and routed that will probably be pretty good. Picked up some good hole saws and an interesting finishing saw today.

[Hdale85]

That's a sexy cabinet...... So is it an open back mid? Or there is just a tunnel for the midrange chamber? I'm guessing the later.

[augerpro]

Jon I must have missed it but where are you crossing the Accuton mid to the SEAS woofer? And this will be a Duelund filter? I really like the overall concept of this Ardent, and Accuton is IMHO one of the few really doing hardcones right. I've been eyeballing both the 2" and 3" for a WAY in the future project. Both are nice, with the tradeoff being where the designer would rather crossover-in the middle of the midrange, or higher but above where the ear is most sensitive.

[Hdale85]

I'll probably start collecting drivers and what not for this project over the next 6-12 months. The cabinets will take some time I'm sure though lol.

[dwk]

I'll probably start collecting drivers and what not for this project over the next 6-12 months. The cabinets will take some time I'm sure though lol.

I actually have the drivers on board for the 'cheapie' version, but I'm thinking the cabinets will be a 6+ month project at least - given how fast I move it could easily be over a year. I guess there was no real need to be so aggressive on the drivers :roll:

Jon (or others) - a question I've had pending since the first of the clamp money shots - have you looked at vacuum clamping? I figure that if I'm looking at this as a chance to do vacuum veneering, why not also use it for clamping. Not only save $$$ on clamps, but also storage and organization space. Of course, I haven't looked into the practical realities of trying to do precision layups in a vacuum bag, so this may be a bad idea.....

[Hdale85]

I plan on doing the high end version. I'm really not sure how long it'll take me to do the cabinets as I've never had a space for a shop until now so I've always built them in my kitchen and dining room.

I haven't heard much of vacuum clamping. I do know a vacuum system can run some bucks as well though. I'd love to get a vacuum setup for veneering though as I keep hearing its the best way.

[bigg]

vacuum clamping?

I've heard that you need something like 300 or 400 psi of clamping force for a good bond when glueing up speaker cabinets. I don't know if this is really true. But some of my clamps are rated to do 1100 psi. How would you get this kind of pressure with vacuum clamping? Also, is there a point where the bonding agents need air to cure properly? Waiting on this project. :Z It's going to take too long to get my shop properly equipped. :T

[Hdale85]

Well I'm probably going to be here for another 3 years or so so figure I might as well work on a project in the mean time.

[JonMarsh]

Jon I must have missed it but where are you crossing the Accuton mid to the SEAS woofer? And this will be a Duelund filter? I really like the overall concept of this Ardent, and Accuton is IMHO one of the few really doing hardcones right. I've been eyeballing both the 2" and 3" for a WAY in the future project. Both are nice, with the tradeoff being where the designer would rather crossover-in the middle of the midrange, or higher but above where the ear is most sensitive.

This is the target crossover function that has been used for modeling and evaluation to date:



It is a Duelund alignment, forgot the aleph at the moment, it was chosen based on crossover frequencies and bandwidth requirements for the midrange, tweeter, and woofers, in that order.

Yes, some of the Accuton's are fairly special; I've got C88's and C89's I've played with, but the C79 is the choice pick in their "small" midranges, in my opinion. Nice workable response and sensitivity, and very good distortion behavior.


@ 90 dB output, 2.83 VRMS drive

For clean phase and amplitude tracking with this target function and nominal 300Hz and 2700 Hz crossovers, the mid should be capable (at least at lower level) from 100 Hz to 8 kHz; not an easy target.

Note that you can see the effect of cone resonance amplification in the 3rd harmonic plot (dashed - following the same amplitude curve but at 1/3 frequency), but the level is quite low. The C79 has a very short stiff frame, compared even with the C88 and C89, and this seems to avoid resonances which sometimes show up as bumps in the distortion curve.

[JonMarsh]

I actually have the drivers on board for the 'cheapie' version, but I'm thinking the cabinets will be a 6+ month project at least - given how fast I move it could easily be over a year. I guess there was no real need to be so aggressive on the drivers :roll:

Jon (or others) - a question I've had pending since the first of the clamp money shots - have you looked at vacuum clamping? I figure that if I'm looking at this as a chance to do vacuum veneering, why not also use it for clamping. Not only save $$$ on clamps, but also storage and organization space. Of course, I haven't looked into the practical realities of trying to do precision layups in a vacuum bag, so this may be a bad idea.....

That's some interesting question, but I wonder how that would work out in practice?

I've looked into vacuum veneering, and ended up getting scared off by the cost of a good pump and good large bags. Vacuum veneering can generate pressures of 10-12 lb/sq in. without much trouble. It's best done with glues like Unibond, though many folks still use PVA cold press veneer glue; sometimes it's a bit more hassle with the latter because the veneer will start to curl from the moisture in the glue- you have to get it under pressure quickly.

Now, I've see cold press veneer glue that quotes 100-250 lb/in (titebond) recommended clamping force (not remotely possible with a vacuum bag). Pro-Glue doesn't quote clamping pressure, but then it's a product of VAC-U-CLAMP (I've got two bottles of it as wellas the Titebond PVA veneer glue).

I've turned this portion of the cabinet work over to Evil Twin, who is convinced that he can do all the veneering with mechanical cold press techniques (can't complain about how the front panel worked out).

No, I don't own stock in Bessy, but maybe I should. I don't think a vacuum clamp for assembly operations would work well for what I'm doing; I'm actually using clamps at some points to line up work pieces initially, then moving them to more conventional positions after other clamps have been installed. And the clamping force on heavy pieces is much higher than what a vacuum bag can generate; plus, there's the heavy angle iron stock I use at times to insure the glued up piece is perfectly straight.



This will be documented in a lot of detail as I put the web site together; obviously anyone interested is free to innovate and come up with better ideas; it's what I'd expect out of you guys. :W

[BobEllis]

I've heard that you need something like 300 or 400 psi of clamping force for a good bond when glueing up speaker cabinets. I don't know if this is really true. But some of my clamps are rated to do 1100 psi. How would you get this kind of pressure with vacuum clamping? Also, is there a point where the bonding agents need air to cure properly? Waiting on this project. :Z It's going to take too long to get my shop properly equipped. :T

I think you are forgetting that 300 psi under the clamp pad is spread over a lager area as you clamp up. If we really needed that kind of pressure you're talking over 43,000 pounds of clamping force per square foot.

All you need is enough pressure to bring the pieces into uniformly close proximity. Assuming that your panels are clean and free of debris, you shouldn't need a lot of force to hold them together.

Even if you only pull 10 psi of vacuum you are getting 1440 pounds per square foot of clamping pressure. I've used piles of weights giving less than 100 pounds per square foot and successfully glued panels of multiple layers of mdf together. My standards aren't quite as high as Jon's