Ardent Speaker Camp

[Evil Twin]

That information is under Imperial Interdiction.

Mr. Marsh will be sent to spend some time with an Imperial Interrogation Droid to ascertain whether more information been "leaked" to Rebel spies or other scum. Such breaches in security will NOT be tolerated.

The Chancellor is most displeased...

[CraigJ]

Ya know, I think I'll stick to my LBL for a while...

Wow, could that be the 2010 Phoenix? "And there's an SS 8" model I have my eye's on for a new application" paired with a Revelator tweeter? Oops, I'd better be quiet before the evil :storm: comes. RUN!

Craig

[AlanH]

That information is under Imperial Interdiction.

Mr. Marsh will be sent to spend some time with an Imperial Interrogation Droid to ascertain whether more information been "leaked" to Rebel spies or other scum. Such breaches in security will NOT be tolerated.

The Chancellor is most displeased...

...many Bothans died to bring us this information...

[chasw98]

Actually the Bothans agreed to hold on to the information for 24 parsecs while Mr. Marsh tidied up his affairs. I guess Mr. Marsh has ruined it for all involved. The galaxy will not be safe for a while to come.......

[Curly Woods]

That information is under Imperial Interdiction.

Mr. Marsh will be sent to spend some time with an Imperial Interrogation Droid to ascertain whether more information been "leaked" to Rebel spies or other scum. Such breaches in security will NOT be tolerated.

The Chancellor is most displeased...

John, you have screwed up really good this time :-)

[---k---]

That information is under Imperial Interdiction.

Mr. Marsh will be sent to spend some time with an Imperial Interrogation Droid to ascertain whether more information been "leaked" to Rebel spies or other scum. Such breaches in security will NOT be tolerated.

The Chancellor is most displeased...

HEY! Who you calling Rebel Spies and Scum!

[neuro]

This design is looking great! Can't wait for it and the other new stuff that's being cooked up.

Given the projected cost of the passive crossover, what are peoples' thoughts on an active design purely from a price/performance standpoint? How spendy does one need to go on op-amps (or dsp?) to best a good passive build? How spendy on the amp channels? What if we compared premium drivers in a passive build with the budget drivers in an active build? Would the slightly less ideal behavior of the the budget drivers be compensated for by giving each amp channel the sole purpose of controlling one driver?

[Hdale85]

Well you would need 6 channels of amplification to go active. And given how good these speakers are they would need to be good amps. Pretty sure 4 more amp channels are going to cost more then what the passive crossovers cost.

[chasw98]

From the Marchand system a chassis for a fighter code named the XM44 has been procured (actually 2 of them). They will be customized and designed and executed with Pass and Aragon technology to see what they will do to best the Ardent way. Unfortunantely they will not be ready for RMAF but soon after for Xmas on Tattoine!

[JonMarsh]

Hmmm, three Ayre V5 would be kind of pricey... even a loaded Ayre V6 multi-channel amp would be daunting.

And realizing the right filter contours in a passive wouldn't be trivial.

Let's leave that idea to the Y in DIY. Undoubtedly going active and getting rid of cheap crossover components in the signal path can help. Undoubtedly some of the benefits of the Orion derive from that. But an 60 w/ch integrated should drive these nicely (Ayre AX-7e), and having six channels of comparable quality and all the cables involved would drive the price up quickly, me thinks. So we'll throw the door wide open to anyone else that wants to try that out and be a trail blazer. We can even provide LspCAD transfer function plots to emulate in anyone's electronic crossover design. :W

[neuro]

Yeah, the amplification might be too expensive. Then again, if we are assuming the use of a decent existing amp on the woofers, a couple of the well regarded yet inexpensive tripath amps/modules might be enough for the mids and tweeters. The RS100-4s are only rated for 45 watts max (the Seas tweeters are good to significantly more, but never going to see it if the mids are kept safe).

So, if we think of it as buying two more of whatever decent two channel amp would be used with the passive design, then yes, probably more than the passive crossover parts. With a little creativity though, maybe something could be done. In large part, the price parity (of at least the ballpark variety) depends on what you consider good enough for the active amplification. Emotiva good enough? ICEpower good enough? Mark Levinson or bust?

[neuro]

Yes, definitely bigger Y. Cable cost would factor in also. Originally I had in mind collocating the amps with the speaker (either built in or very near). However, trying to reuse an existing two channel amp makes that a little more difficult.

Well, no need to get too far ahead of myself. 1. Finish dissertation. 2. See what wins between Ardent, M8ta-3, and NeoD++. 3. Think about making an active version .

[Biff]

Concrete baffles aren't hard

Hmm...was that thread an April fools joke or something? Honestly....Did you see the driver mounted in it? I'm sure it functions...but it sure don't look pretty at all.

+1 ! They don't need to look all that rough! When I was kid I used to make a bit of pocket change making aquarium decorations. If you wanted to make, for example, a concrete version of the secret MTM baffle, we would make a table of plywood boxed in with 2x4 and fill it with filter grade sand, dampen, and screed off the top, then press in any shape we wanted. Quikrete ladled in, and if it was going to be a big piece poke in some plastic window screen material and tap the edges and underside with hammer until it was flat and no bubbles rose. Let it rest for a day or two and you'd have a fair casting! Quick rinse with dilute muriatic and done. We lined our forms with crushed stone, but I could see a baffle made this way and finished in bed liner being sweet, and deader than Hoffa.

[Arc00]

One way to clean up an active cabling would be a SpeakOn connector and a 8 connector snake wire.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=092-051

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=092-069

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=100-491

[Face]

I love the review:

Used these in a 5.1 surround project in a 97 TransAm. The connectors were awesum.... I will use these in any installation in the future. I thank Parts Express for selling a real professional line of connectors and being so close to me to pick up. Thanks Parts Express....

Jon, gold platter copper, don't accept anything less.

[Bear]

Yeah, the amplification might be too expensive. Then again, if we are assuming the use of a decent existing amp on the woofers, a couple of the well regarded yet inexpensive tripath amps/modules might be enough for the mids and tweeters. The RS100-4s are only rated for 45 watts max (the Seas tweeters are good to significantly more, but never going to see it if the mids are kept safe).

You may want to re-read some of the discussion on the NeoD CC. Several people have commented on being able to hear differences in amps, and Jon's stated goal is to make this one better. I'd be really careful about making assumption about what quality of amps are sufficient for something like this. I wouldn't necessarily put my Bryston up against Jon's Ayre, but if you are building something that has 70+ dB of noise-free headroom, then an amp that is at least as good as that is important (s/N >100dB, THD <0.01%). Otherwise, you'd be better off going with a much less demanding/transparent speaker.

So, if we think of it as buying two more of whatever decent two channel amp would be used with the passive design, then yes, probably more than the passive crossover parts. With a little creativity though, maybe something could be done. In large part, the price parity (of at least the ballpark variety) depends on what you consider good enough for the active amplification. Emotiva good enough? ICEpower good enough? Mark Levinson or bust?

ICEPower would be fine for the bass, but I suspect you could hear the switching issues in the mid and tweeter. Might be an interesting, but expensive, thing to test.

Bill

[JonMarsh]

Base design and drawing a PITA...

Maybe I'm just getting lazy, maybe it was the past week at work!! Definitely on the ugly side. Work, that is... :W

Finished it up, though, listening to some Ottmar Liebert on the music server. Seriously nice music and sound. The changes in my system over the last six months have revitalized my music collection, and I think another revolution may be coming soon.





Should have these fabricated before COB Monday- the MDF layup is already done, and the maple is on hand and ready, as well as all the hardware for assembly. I've got some phenolic sheet for fabricating a template for the mounting hardware (1/4-20 threaded inserts and connector bolts).

[JonMarsh]

Saw dust is our most important product...

Been making a fair amount of that this weekend...




Sawdust CGI courtesy of Lucasarts, Chuck!

[Hdale85]

So the riser being right at the edge of the port flare won't effect anything much? Looks really nice!

[JonMarsh]

The whole base sits on points off the floor a ways- they're on the 1-1/2" maple that's laid flat to the MDF.

[chasw98]

Been making a fair amount of that this weekend...




Sawdust CGI courtesy of Lucasarts, Chuck!

Yes, it is especially nice to see some sawdust on the router. Nice touch!

[JoshK]

Well this thread 'made' me spend more money. Was in HD yesterday ordering some custom faucets. Wife had opened a HD card to get the 10% (bill was north of 1200 bucks).

I saw that the big box carried the Bosch Colt VS palm router for the same price as amazon. So I seized the day. I already have 3 routers, but what is one more? Especially when it is a nice palm sized unit.

They didn't have the angled attachment, I ordered that off amazon.


Some other thoughts and musing. I took this week off to finish the bathroom and redo the roof. We did some research and decided on the rubberized roofing (elastomeric). Its painted on and it actually expands and contracts without cracking, unlike tar. http://www.amesresearch.com/

Well, it gave me an idea. If they use some of this stuff to make mock up boats and water tanks, why couldn't you use this on the inside of speaker cabinets? The elasto-barrier is a vapor barrier, so it'd water-proof your cabinets from the inside at least. Its rubberized, so I'd imagine it'd have some sound dampening properties.

[lbstyling]

Ryan, I haven't done the mechanics math and I don't doubt yours. And CJD, I don't know of any wood glue that would stand up to 1900psi either, so either the wood would fail, or the glued butt joint. But you got me thinking about what we use bracing for, and really, its for resonance control and not structural integrity, and I think CJD was on to something. Think about the box panels that a brace is, well, bracing. The panels have to be literally flexing while they're resonating--in other words, the panels themselves are undergoing oscillatory stresses (tension and compression about the neutral axes of the panel due to moment/shear stresses). This, combined with the brace's deformation, we have a statically indeterminate situation, so we must talk about relative E's (Young's modulus) and relative stresses.

Though I'll readily admit that I'm a bit of a charlatan when it comes to acoustical resonance of structures, my conjecture is that even if the brace isn't absolutely rigid (modulus less than infinity), it's still rigid enough to "convince" the box panels to resonate in such a way that a flexure node would appear at the braced point of the panel. This is because the panel will deflect (and this is the key to my point) in a moment/shear type stress relatively easier than deforming/straining the brace axially. In practice, say a panel has a fundamental resonance at 800hz and we brace in the dead center of the longest dimension of it. I would bet the new fundamental will be more like 1600hz and lower in magnitude. And since the braced point is a node at the fundamental, it's not moving and therefore, in theory, not causing mechanical deformation (and no oscillating tension/compression axial stress) on the brace.

Now that I've thought about it, perhaps thats a good rule for deciding when you have "enough" bracing. When the stress required to deflect an unbraced portion of a panel a given amount is greater (and it becomes greater as the unbraced portion becomes smaller) than the stress required to axially deform the next brace...don't bother with the extra brace because you may not be moving the resonance much higher. Granted, I haven't tested this idea, and I'm no expert. Forgive any imprecise use of terms in the above as well, I hope my point shows through.

Now, as for why oak or any other hardwood is "better" for bracing over other materials in terms of sound quality...I don't know. As long as wood has the same general moisture content, is free of knots/defects and load is applied in the same way with respect to the grain, most woods we would use have similar moduli. Has Geddes ever gathered empirical data that the oak brace works better than say, a pine or MDF brace? If he hasn't, then knowing him, he should be the first to admit its merely an opinion or preference of his.

just a thought- this all make sence to me- but wouldnt the majority of resonance from a braced panel likely be in sympathy with the panel at the other end of the brace?-kind of like a piston arm between the piston and the crank -possibly even(in a unlucky case) the braces could increase panel noise?
i suppose this would be more likely when a panel is too thin in the first place. just my 2$

assuming the brace was between 2 walls where this wasnt the case-or even between a wall and a theoretical infinatly ridged wall- output would be determined by panel sise x kinda xmax :lol: -but as you need to move 4 x the air to maintain the same spl at half the freq-as i realy cant see a brace expanding and contracting very far you could possibly get a better responce with mdf or something with a low q??

[lbstyling]

please excuse my discalexxeeeia and general lazyness with spelling!!

[lbstyling]

continuing my ramblings- would bracing between the center of a panel and a opposite corner be a improvement?-it would end up like a roll cage.hmmm.....triangulation

[bigg]

Well I'm just putting in one cent worth. When I brace my cabinets I brace from one wall to the other but I don't do it in the middle. I've always braced so that the sections either side of the brace were not equal. So that there would not be two equal or sympathetic resonances. All wrong? I'm not a physicist. Please let me know Obi-Wan ;x( .

Also---is there any difference between MDF and plywood for bracing? I'm currently using 3/4 inch plywood but I've seen pictures from some professional speaker companies and it looks like they are using @ 2" thick MDF for their internal braces. (Maybe my questions are so elementary they will lull the Emperor to sleep :Z )

[JonMarsh]

Well I'm just putting in one cent worth. When I brace my cabinets I brace from one wall to the other but I don't do it in the middle. I've always braced so that the sections either side of the brace were not equal. So that there would not be two equal or sympathetic resonances. All wrong? I'm not a physicist. Please let me know Obi-Wan ;x( .

Also---is there any difference between MDF and plywood for bracing? I'm currently using 3/4 inch plywood but I've seen pictures from some professional speaker companies and it looks like they are using @ 2" thick MDF for their internal braces. (Maybe my questions are so elementary they will lull the Emperor to sleep :Z )

This is the ideal way to do it- and at golden mean ratio, i.e., 1.68:1.

Internal braces rely primarily on compression strength. MDF has good compression strength, not so good bending strength. MDF is less expensive and somewhat easier to work, though the cheap stuff chews up blades a bit- cleaning your blades and router bits with acetone now and then helps. I used MDF for the braces in the Ardent. For the front panel, I think a composite material or stiffer material than MDF is desirable- you wouldn't use MDF for an electric guitar sounding board.

[kvardas]

Finished it up, though, listening to some Ottmar Liebert on the music server. Seriously nice music and sound. The changes in my system over the last six months have revitalized my music collection, and I think another revolution may be coming soon.

Might I suggest Bruce Becvar's CD "Arriba".

[JonMarsh]

I'm always interested in music suggestions-

You mean:



I'm putting together a music order from Amazon, so your timing is good!

Are you familiar with Tommy Emmanuel, from Australia? He has a number of great albums, this live one is pretty special:

[bigg]

This is the ideal way to do it- and at golden mean ratio, i.e., 1.68:1.

Internal braces rely primarily on compression strength. MDF has good compression strength, not so good bending strength. MDF is less expensive and somewhat easier to work, though the cheap stuff chews up blades a bit- cleaning your blades and router bits with acetone now and then helps. I used MDF for the braces in the Ardent. For the front panel, I think a composite material or stiffer material than MDF is desirable- you wouldn't use MDF for an electric guitar sounding board.

Thanks Jon. I wasn't talking about the Ardents. I just saw the discussion about bracing and thought I would get that resolved. Thanks for the golden ratio theory. I'll have to try that. I'll check some of the speakers 'in progress' and see how they compare to the golden ratio. I think I might be pretty close. I don't know when I'll get to the Ardents. Maybe by the time I get to them I could afford to do the premium version. :lol:

No, I wouldn't use MDF for a guitar. But the guitar is an originating point for the music's sound. And a speaker is reproducing that recorded (hopefully well recorded) sound. I don't see the speaker as an instrument to add or contribute it's own sound to the event. So while I'm open to try other materials for the front baffle (I really love the MTM LBL baffle pictures) I'm not worried about using MDF. (Actually the stuff I use looks more like HDF).
Of course when I build the Ardents, I will follow your design. Unless I decide to build your next one instead. (Yes those LBL front baffles look awesome! :T )

Gary

[JonMarsh]

The ideal solid body guitar is an extremely stiff non-resonant platform, that does not suck energy from the strings at any frequency, but allows them to play with whatever sustain or percussion that the guitarist may find possible- it strikes me, as a former guitarist, that a speaker front baffle should behave similarly. That's my main premise here... Magico, YG Acoustics, Rockport, and some others believe the same thing, and for good reasons, I think. No one I know in the business (as opposed to in DIY) thinks MDF is a good cabinet material anymore.


Just think about it a bit.... :W

[kvardas]

That's the CD.

I'll check out your recommendation.

Thanks

[Dennis H]

Mmmmm, guitar. Watched Stevie Ray Vaughn on PBS last night -- clips from several concerts. :T

[bigg]

The ideal solid body guitar is an extremely stiff non-resonant platform, that does not suck energy from the strings at any frequency, but allows them to play with whatever sustain or percussion that the guitarist may find possible- it strikes me, as a former guitarist, that a speaker front baffle should behave similarly. That's my main premise here... Magico, YG Acoustics, Rockport, and some others believe the same thing, and for good reasons, I think. No one I know in the business (as opposed to in DIY) thinks MDF is a good cabinet material anymore.


Just think about it a bit.... :W

OK. Hmmmmmm.... Well I know guitar builders sometimes offer an option of what wood you would like them to use when they build your guitar, or they have their own preference. Because the different woods affect the tone differently. AFFECT the tone? I only want my speaker to reproduce what was originally recorded. Now that being said hopefully your composite baffles or the LBL baffles are very neutral in their presentation. But I tend to doubt that a perfectly neutral baffle exists, maybe concrete would do it. I don't know. After all, as my avatar says, I'm still a geek in training.

[Biff]

Are you familiar with Tommy Emmanuel, from Australia? He has a number of great albums, this live one is pretty special:

[/QUOTE]

Tommy used to play annually down here on the Outer Banks and I was lucky enough to get him to sign a copy of the double CD - Todd Rundgren once said that Tommy Emmanuel is the two best guitar players he ever heard.

Some others you might like to listen to - John Williams Magic Box with John Etheridge, they play very well together.
Philip Hii, Chopin Nocturnes
Jeff Lang, disturbed folk
Jesse Cook's Vertigo
Antonio Forcione Live (very good energy here)
and a partner in crime of mine, Gordon Kreplin, Bach in Brazil

[JonMarsh]

OK. Hmmmmmm.... Well I know guitar builders sometimes offer an option of what wood you would like them to use when they build your guitar, or they have their own preference. Because the different woods affect the tone differently. AFFECT the tone? I only want my speaker to reproduce what was originally recorded. Now that being said hopefully your composite baffles or the LBL baffles are very neutral in their presentation. But I tend to doubt that a perfectly neutral baffle exists, maybe concrete would do it. I don't know. After all, as my avatar says, I'm still a geek in training.

Yeah, well MDF totally screws up the tone by absorbing a lot of the sound itself and having resonance at relatively low frequencies- dense hardwoods affect the tone by NOT absorbing sound and being quite stiff.

I'm not trying to start a religion here or anything- would be happy if others took this to heart a little and thought about it- but in a sense, it doesn't matter personally to me if anyone does or doesn't in the DIY community. Wouldn't want to be accused of keeping good ideas to myself, but realistically, everyone does what they want...

If I viewed this as a competition or a Sith Lord kind of thing, I wouldn't talk about it at all, I suppose... :W

[JonMarsh]

Are you familiar with Tommy Emmanuel, from Australia? He has a number of great albums, this live one is pretty special:

Tommy used to play annually down here on the Outer Banks and I was lucky enough to get him to sign a copy of the double CD - Todd Rundgren once said that Tommy Emmanuel is the two best guitar players he ever heard.

Some others you might like to listen to - John Williams Magic Box with John Etheridge, they play very well together.
Philip Hii, Chopin Nocturnes
Jeff Lang, disturbed folk
Jesse Cook's Vertigo
Antonio Forcione Live (very good energy here)
and a partner in crime of mine, Gordon Kreplin, Bach in Brazil

Thanks for the suggestions, Biff! Now that I've got a decent little music server, it's a lot easier to enjoy a plurality of music and find it when I want to listen!

~Jon

[bigg]

Hi Jon,
The MDF or HDF that I use has a hard veneer of birch or oak on it. Plus several layers of poly finish on that. But the part that the driver is screwed or bolted to is the MDF or HDF. Is that the problem area you were talking about or the baffle surface area?

[kirknelson]

...it strikes me, as a former guitarist, that a speaker front baffle should behave similarly. That's my main premise here... Magico, YG Acoustics, Rockport, and some others believe the same thing, and for good reasons, I think. No one I know in the business (as opposed to in DIY) thinks MDF is a good cabinet material anymore.

Does this line of thinking pertain only to the front baffle or to all sides of the cabinet.

I thought the energy absorption or dampening qualities of MDF was what was wanted on all sides except the front baffle and that was why it was used (well one of the reasons at least). It just usually gets used for the baffle as well since the builder has the material on hand.

[JonMarsh]

A little more measurement work done, a little more design work.

One more pass this weekend, then time to order parts.






What I forgot to copy was the impedance curve, which looks more like an interstate highway than a mountain road. :W

[chasw98]

L7, L8, and L9 will set you back a few sheckels, eh? And C9 is no slouch either.

[JonMarsh]

The zobel coils can be really high DCR- I have to admit I'll probably go back and double check all values, but LspCAD doesn't lie about what it takes to make good conjugate networks, unfortunately. Tweeters with really low Fs are both a blessing and a pain. :W L7 is just two 8 mH 18 or 20 AWG coils in series- not that bad cost wise. The last iteration of C9 was 1,000 uF- using the 10% Dayton's, it's not too bad- the cheap seats will use NP electrolytics, I guess. I'll post the Z curve later today...

I have the feeling this is all "gelling", if you know what I mean. You've got email on a related topic.

[Face]

Parts Connexion has 15% capacitors till the end of the month.

[chasw98]

The zobel coils can be really high DCR- I have to admit I'll probably go back and double check all values, but LspCAD doesn't lie about what it takes to make good conjugate networks, unfortunately. Tweeters with really low Fs are both a blessing and a pain. :W L7 is just two 8 mH 18 or 20 AWG coils in series- not that bad cost wise. The last iteration of C9 was 1,000 uF- using the 10% Dayton's, it's not too bad- the cheap seats will use NP electrolytics, I guess. I'll post the Z curve later today...

I have the feeling this is all "gelling", if you know what I mean. You've got email on a related topic.

Would you adjust the 'R' in the LCR circuit to compensate for a high DCR in the inductor? Got the email. Thanks.

[JonMarsh]

Would you adjust the 'R' in the LCR circuit to compensate for a high DCR in the inductor? Got the email. Thanks.

Oh, very definitely I would- so if the coil has a DCR of two ohms, and there's two in parallel, and the target total R was 8 ohms, for example, I'd only use 4 ohms in the resistor. LF zobels like this can see some significant power, too, so we won't be using wimpy little 10 watt resistors... :W