Ardent Speaker Camp

[cjd]

Talk about conflicted... Kevin's going out of business sale at DIYCABLE!

The Exodus UnAnarchy is back at a bit under $50 each- anyone else think this might be an interesting budget solution for the Ardent, provided you're willing to live with the lower impedance of midwoofers in parallel? Net sensitivity could wind up fairly decent, but in a three way with two 6.4 ohm DCR woofers in parallel we're likely to see no better than 3 ohms for the mid bass efficiency... but when they're gone, they're gone. Might make a killer small three way, with RS52 midrange dome.

I might have to get a pair of these just for a special build of the NeoD CC center channel for GF.

Hope there's some left when I get back from hiking trip!

I always wonder if I should have put a mid in the Anarchy, but it sounds so good even as a 2-way. Awesome woofers. I wouldn't have gone RS52 but ...

[Face]

I use an 8ohm SS 10F as a mid with a pair of Anarchy woofers, sounds great. Soon I'm going to give the SS 15M/4624G a try with the Anarchy. One other issue is that they need a long port or a passive radiator, in a .75ft^3 enclosure, the SEAS SL26R is a perfect match(Fb 30hz8O).

[JonMarsh]

I always wonder if I should have put a mid in the Anarchy, but it sounds so good even as a 2-way. Awesome woofers. I wouldn't have gone RS52 but ...

Well, you know, I think I'm the only guy that's ever done a design with the RS52 and been quite pleased with the result. And not because I have a tin ear! Just takes a certain technique. I have some new ideas about other ways to handle it...

[JonMarsh]

I use an 8ohm SS 10F as a mid with a pair of Anarchy woofers, sounds great. Soon I'm going to give the SS 15M/4624G a try with the Anarchy. One other issue is that they need a long port or a passive radiator, in a .75ft^3 enclosure, the SEAS SL26R is a perfect match(Fb 30hz8O).

That sounds like an interesting combo and approach!

[cjd]

Well, you know, I think I'm the only guy that's ever done a design with the RS52 and been quite pleased with the result. And not because I have a tin ear! Just takes a certain technique. I have some new ideas about other ways to handle it...

Zaph did one he was quite happy with by all reports.

The people that are loudest about its sound being "not liked" don't tend to produce results that overwhelm me, despite their reputation. They manage a "meh" - flat response, but something missing.

That huge faceplate keeps me at bay.

C

[JonMarsh]

Thanks for the feedback- it always seemed funny that there were so many guys on TechTalk hating that driver!

Yeah, the faceplate is a bit of an obstacle- not insurmountable, but not trivial- hence the way the NeoD CC was done.

I'm feeling a bit of an increasing itch to revisit that design. Some of the things done in the original NatalieP as well as the latest beast give me some ideas- I gave a presentation about how a slightly modified LR3 sort of alignment can work usefully in some specific cases, where there IS a significant time offset of the high and low frequency drivers. In this case, it would be the mid to woofer, instead of the tweeter to midwoofer. Probably should model it thoroughly before making any plans!

[dlneubec]

Zaph did one he was quite happy with by all reports.

The people that are loudest about its sound being "not liked" don't tend to produce results that overwhelm me, despite their reputation. They manage a "meh" - flat response, but something missing.

That huge faceplate keeps me at bay.

C

Chris, I have to say that I find this kind of low to take a pot shot at someone who happens to not like a particular driver. I have heard two different versions of Zaph's design at the Iowa DIY, and probably a half dozen different versions of RS52 based designs, none of which inspired me to want to use the driver. I used it in a prototype omni a number of years back that I never was happy with and abandoned, but never in a traditional way. I doubt it had anything to do with the driver in my case, however. Granted, I haven't heard Jon's implementation, which I'm sure is very well designed and carefully thought out, but there are a lot of guys out there who are just as knowlegeable and skilled as the folks here at HtGuide, so let's not discount their efforts.

From what I have heard, I would not take the chance on the RS52 either, nor recommend it to others. The best we all can do, underwhelming as that may be to some, is base our decisions on our own level of knowlege and experience.

[Face]

Roman(R-Carpenter) did a WMTMT design using the RS52 and it sounds very nice. After all the bad press that driver has received, I was surprised.

[Mark65]

I heard that driver in a very well thought out three way, LouC's "Cyclops" The sound was indeed "meh". I don't believe that the person in question has ever taken a shot at you, so I'm not sure why you would use this forum to take a shot at him.

If you like the driver, that's fine, but IMHO, your statement was bad form.

Also, I find his designs to be lively, engaging, and eminently listenable. YMMV, of course.


Mark

[JonMarsh]

Was in the storage unit Friday putting things away and came across the Anarchy drivers- a reminder of all the things that have gotten put on hold since the change in my work situation! :M

And at first I thought maybe these were some Wavecor drivers I'd bought and forgotten- that's how much stuff is getting pushed out of short and mid term memory by other recent events!

This led me to go back and look at the Wavecor site, which has some interesting new 7" and 8" drivers using their balanced field drive.

http://www.wavecor.com/html/wf182bd09_10_11_12.html

That also led me to go back and look their subwoofer series with balanced drive, and the 7" model available in 8 and 4 ohm- looks to have a pretty clean top end, though not very sensitive. Well, I'm not using SET amplifiers, either....

http://www.wavecor.com/html/sw182bd01_02.html

More things to wish I had time to do something about...

[dar47]

The 7" is playing real nice in my new centre.

I've been play with your Ardent cab drawings to fit the SW223BD01 in. The baffle looks to need to go to 11.25" w but the 0.75 ft^3 per driver sealed is perfect for the Ardent cab. One thing I'm not sure on though is the small mid space you have got for the C90-9-79. I was thinking 0.35 ft^3 for the C90-9-79?

When I get it modeled I'll post. I may have use of a 5 axis CNC to do the cabs, let me know if you want to do a full new pair with the SW223BD01.

[JonMarsh]

The 7" is playing real nice in my new centre.

I've been play with your Ardent cab drawings to fit the SW223BD01 in. The baffle looks to need to go to 11.25" w but the 0.75 ft^3 per driver sealed is perfect for the Ardent cab. One thing I'm not sure on though is the small mid space you have got for the C90-9-79. I was thinking 0.35 ft^3 for the C90-9-79?

When I get it modeled I'll post. I may have use of a 5 axis CNC to do the cabs, let me know if you want to do a full new pair with the SW223BD01.

THAT I would be very interested in contributing to! Please keep us informed!

[benthe8track]

THAT I would be very interested in contributing to! Please keep us informed!

Awesome! I've been excited about building a set of Avalon-ish speakers since you started this thread way back.
Well see about access to the 5-axis (though I think we can do it with a 3-axis as well) next week, would be a simple matter to cut a third set and flat pack it to you provided the shipping isn't prohibitive.

I'm modeling these guys in solidworks currently using the drawings you gave dar49 (my dad) and myself--now I'm running into some questions:
What are the criteria for the facet shapes? I've been pouring over as much literature as I can find on detraction but "Direct Radiator Loudspeaker Enclosures", Olson, 1953 only really tells me that facets are good, not how to design them. Additionally, it looks like you started experimenting with felt to mitigate defraction around the tweeter, I was thinking we can build this into the grill (which I think is what Avalon does?) then build the x-over that way?

Finally, from every picture I could see from inside the Avalon factory the enclosures all seem to be made out of MDF. If it's good enough for them is bamboo, baltic birch, ect, overkill?

Anyways looking forward to your reply. I have about 6 months to build these guys before I move to another city and lose access to the old mans tools.

[JonMarsh]

Some thoughts about your questions -

What are the criteria for the facet shapes? I've been pouring over as much literature as I can find on detraction but "Direct Radiator Loudspeaker Enclosures", Olson, 1953 only really tells me that facets are good, not how to design them. Additionally, it looks like you started experimenting with felt to mitigate defraction around the tweeter, I was thinking we can build this into the grill (which I think is what Avalon does?) then build the x-over that way?

In this case, the narrow triangular front is not concerned much with diffraction control (that's not avoidable- just having an edge creates diffraction), but rather reduces the baffle width and raises the BSC frequency- so that below that frequency, you have wider dispersion. You see this trend also in dipole speaker designs- trying to make the dispersion more uniform over a wider range of frequencies.

Yes, Avalon builds diffraction control felt into the grille; I've done this with other projects like the M8 and M8ta. It's the easiest way to handle it.

Finally, from every picture I could see from inside the Avalon factory the enclosures all seem to be made out of MDF. If it's good enough for them is bamboo, baltic birch, ect, overkill?

well, I'm not going to go say that you can't build a good speaker with MDF, but I'll note that my Ardent set uses bamboo in the baffle construction. Also, state of the art in loudspeaker cabinet construction is more in evidence in company's like Wilson Audio, Magico, YG Acoustics, Rockport, etc- Avalon's basic cabinet construction techniques haven't changed significantly from what I was doing in the late 70's and gave to my friend Charlie Hansen who founded Avalon and developed their first models, the Eclipse and Ascent. Actually, those early prototypes I have Charlie were a bit more sophisticated than what Avalon usually does, having multi-layer constrained damping using a form of Celotex as an internal damping layer.

I wouldn't personally do the Ardent without the inner bamboo construction- it's such a better material to work with, whether you're looking at strength, stability of any type of screw fastener used to attach to it, whatever... You wouldn't make a solid body guitar out of MDF, now, would you... I feel similarly about speakers, especially after finishing the Isiris construction. (No veneering either, which has some advantages, too). OTOH, good and honest men of high intent will continue to build speakers out of MDF, and generally be pleased with the results. It's a matter of expectations.

Go check out and listen to a set of Magico's sometime... it may recalibrate your expectations.

Then build a small set of a standard design completely out of bamboo... I'm pondering doing that with a set of NatalieP's or a reworked version of that design or the NeoD CC using small monster woofers, maybe Wavecor or my set of NOS Exodus Anarchy (would make more sense to use something available still). I need a set of small monitors for my music playing stuff.

It wouldn't surprise me if I'm looked at as being a radical curmudgeon on this DIY board, and rather wacky to my high end audiophile friends, but it's likely because I'm not stuck in either world, but try to take and use whatever is useful, and works.

OTOH, I can certainly see the utility of CNC MDF, and would be interested in building a set based on that just because of the time it would save, time I'm in a total crunch for with my current work situation. It all depends on how the pieces are built up, and obviously, CNC'ing a composite structure of bamboo and MDF probably isn't feasible. OTOH, just doing the whole FP out of Bamboo might be enough.

[benthe8track]

In this case, the narrow triangular front is not concerned much with diffraction control (that's not avoidable- just having an edge creates diffraction), but rather reduces the baffle width and raises the BSC frequency- so that below that frequency, you have wider dispersion. You see this trend also in dipole speaker designs- trying to make the dispersion more uniform over a wider range of frequencies.

Yes, Avalon builds diffraction control felt into the grille; I've done this with other projects like the M8 and M8ta. It's the easiest way to handle it.

Thanks for clearing that up! I guess I thought the facets were designed to reduce diffraction because in Olsen's paper the most optimally flat response shape (of the ones he explored) appeared similar to these faceted enclosures.

Well plan for felt in the grill then.

well, I'm not going to go say that you can't build a good speaker with MDF, but I'll note that my Ardent set uses bamboo in the baffle construction. Also, state of the art in loudspeaker cabinet construction is more in evidence in company's like Wilson Audio, Magico, YG Acoustics, Rockport, etc- Avalon's basic cabinet construction techniques haven't changed significantly from what I was doing in the late 70's and gave to my friend Charlie Hansen who founded Avalon and developed their first models, the Eclipse and Ascent. Actually, those early prototypes I have Charlie were a bit more sophisticated than what Avalon usually does, having multi-layer constrained damping using a form of Celotex as an internal damping layer.

I wouldn't personally do the Ardent without the inner bamboo construction- it's such a better material to work with, whether you're looking at strength, stability of any type of screw fastener used to attach to it, whatever... You wouldn't make a solid body guitar out of MDF, now, would you... I feel similarly about speakers, especially after finishing the Isiris construction. (No veneering either, which has some advantages, too). OTOH, good and honest men of high intent will continue to build speakers out of MDF, and generally be pleased with the results. It's a matter of expectations.

Go check out and listen to a set of Magico's sometime... it may recalibrate your expectations.

Then build a small set of a standard design completely out of bamboo... I'm pondering doing that with a set of NatalieP's or a reworked version of that design or the NeoD CC using small monster woofers, maybe Wavecor or my set of NOS Exodus Anarchy (would make more sense to use something available still). I need a set of small monitors for my music playing stuff.

It wouldn't surprise me if I'm looked at as being a radical curmudgeon on this DIY board, and rather wacky to my high end audiophile friends, but it's likely because I'm not stuck in either world, but try to take and use whatever is useful, and works.

OTOH, I can certainly see the utility of CNC MDF, and would be interested in building a set based on that just because of the time it would save, time I'm in a total crunch for with my current work situation. It all depends on how the pieces are built up, and obviously, CNC'ing a composite structure of bamboo and MDF probably isn't feasible. OTOH, just doing the whole FP out of Bamboo might be enough.

Sounds good to me, I'm looking at this build as an investment purchase anyways, something I'll keep for 10+ years so if other materials are superior we may as well use them. I don't see why we couldn't make a composite structure of MDF and bamboo? I just need the nominal thickness of the bamboo sheets of whatever we can source locally. Then we can cut the panels, laminate, and assemble the entire enclosure.

Would you prefer bamboo for the sides/top/bottom/bracing as well? Also your preferred volume for the mid and woofers. Once I know that I can finish the other parts. I think I still have your email address so I'll try to fire you some drawings by next week.

[ColoradoTom]

I alternated sheets of high quality MDF and Baltic Birch on my curved Geddes Abbey 12a build and felt that it gave me a best of both worlds - mass and strength. I'm not sure, but my nerd instincts think that having two different materials would help with transmission of vibrations thru the panels as well. All I can say is the sides of my Abbeys are REALLY dead. Hmmmmmm.... Ardent with curved laminated sides and faceted front baffle all done in figured walnut!

Tom

[JonMarsh]

Ardent with curved laminated sides and faceted front baffle all done in figured walnut!

Tom

Now that would blow my mind! :T

[johngalt47]

I bought one of those bamboo cutting boards...Holy Mackerel! I had no idea they were so dense! For its thickness that thing weighs a ton!

[JonMarsh]

I bought one of those bamboo cutting boards...Holy Mackerel! I had no idea they were so dense! For its thickness that thing weighs a ton!

Yeah, isn't it great? :B :T

[Doug Fraser]

While Kevin Haskins has shut down DIY Cable the Ex Anarchys will live on.

There is a pre order here:

http://www.diysoundgroup.com/anarchy-pre-order.html

Delivery to be in Oct 2013.

[wkhanna]

I miss Kevin's site, they had lots Cardus goodies.

[JonMarsh]

While Kevin Haskins has shut down DIY Cable the Ex Anarchys will live on.

There is a pre order here:

http://www.diysoundgroup.com/anarchy-pre-order.html

Delivery to be in Oct 2013.

Thanks Doug! And it looks like they're in stock right now!

That puts a different complexion on some things...

[bigg]

Hi Jon,

This is a huge thread. Do you have the plans for the two Ardent versions published somewhere? Or , shown in this thread somewhere?

[JonMarsh]

Yeah, this thread is totally out of control, like a Russian novel.

It's been mentioned a few times, just PM me for a set of PDF's for the original design. Note that the update "in progress" with the illuminator Scanspeak woofers requires increasing the rebate and through hole for the midwoofers. A web site on SquareSpace was in planning and close to implementation then got turned into an FAE support site at the last minute when our internal IT guys dropped the ball on an iShare capacity and software upgrade. This year has been something of a CF at work. And it continues that way, with me embedded in a customer facility in Cupertino.

[bigg]

Love this stuff!

Hi Jon,

Thanks for the pdfs! I think I will be doing them with the Scan Speak Be tweeter and the Illuminator woofers. (And the Accuton mid.) Are the plans different for those drivers? Is the crossover different? My friends and family think i build great speakers. I tell them I don't know half of it! That You folks on the forums with all your knowledge and test gear (that I don't begin to understand) blow me away!;x(

Do you have a source for the bamboo? I would have to order it and have it shipped. They don't sell it around here.

I like mdf. It's cheap, and readily available. but I don't think it is the be all and end all of speaker building material. If I like the bamboo, I will probably go that way and not miss the mdf. At least on the front baffles.

Thanks again,

Gary

[JonMarsh]

Will do my best to update you fully on the weekend- really tied up right now...

[bigg]

Hi Jon,

Thanks but it's no hurry. I'm finishing up three projects and I will have to buy the components (drivers,crossover parts, wood) a little at a time so that i can afford to do these. Have a nice weekend.

[JonMarsh]

Was at the customer site again today (Saturday). Update in detail tomorrow! :W

[JonMarsh]

Hi Jon,

Thanks for the pdfs! I think I will be doing them with the Scan Speak Be tweeter and the Illuminator woofers. (And the Accuton mid.) Are the plans different for those drivers? Is the crossover different? My friends and family think i build great speakers. I tell them I don't know half of it! That You folks on the forums with all your knowledge and test gear (that I don't begin to understand) blow me away!;x(

Do you have a source for the bamboo? I would have to order it and have it shipped. They don't sell it around here.

I like mdf. It's cheap, and readily available. but I don't think it is the be all and end all of speaker building material. If I like the bamboo, I will probably go that way and not miss the mdf. At least on the front baffles.

Thanks again,

Gary

I worked most of the weekend, but have a few spare minutes this afternoon to highlight the basics- more details hopefully this weekend!

The standard PDFs are with the Seas 7" drivers- the outer frame diameter and clearance hole are slightly larger for the Scanspeak Illuminator drivers, and need to be adjusted based on those. That may even be detailed in the Russian novel of a thread, but maybe not- easiest way is to download the frame info from Madisound.

Here it is:




though I have a solid crossover with the Seas and started developing a minor variant for the ScanSpeak Illuminators (both based on the Duelund concept), I REALLY recommend folks holding off a little while until I can complete development of a version based on the concepts used in the Isiris, which is turn, oddly, derives from the NatlieP, but in parallel mode. This should actually work a bit better, AND use fewer parts and cost less. Live and learn, you know...

I have a single Ardent cabinet already modified for the Illuminators but need to take new data with them. Thanksgiving weekend, hopefully...

I have used a couple of different sources for bamboo- for the Ardents, I sourced 12" wide "boards" (8 ft) from my Pleasant Hill Rockler.

http://www.rockler.com

They don't have this available online; my local Rockler orders it from a specially wood place.

The other source I've used for larger sheets (Isiris project) was Cali Bamboo, who has warehouses all around the country. BUT, this is an order of magnitude more minimum investment, so I suggest looking around locally for someone that handles specialty woods- Google is probably your friend.

http://www.calibamboo.com

Also, another driver for getting the new crossover concept fully worked out is the Wavecor Ardent build, which may be the ultimate Ardent, given the increase in radiating area. Same size cabinet, basically, as regards enclosure volume. A bit more expensive woofer, though. But not outrageously so. :W

[bigg]

Thanks Jon,

Yes I will be holding off for a litlle while. I'm looking forward to the new Dueland crossover design for the 6640 Be tweeter , Accuton C79 mid and the Illuminator woofers. Are other builders interested in this version as well?

[JonMarsh]

Yep! Several guys in contact with me just by email. I will convert the current set completely to that configuration- may wind up as a gift to my daughter.

[bigg]

Hey Jon,

Is that a picture of a Galactica variant on your post? It looks like it has an Accuton midrange with a round frame.

[JonMarsh]

Hey Jon,

Is that a picture of a Galactica variant on your post? It looks like it has an Accuton midrange with a round frame.

First it's probably a good idea to establish what is a variant of what....

The industrial design source of the Galactica as well as the Isiris is the Avalon Isis.




This is a very low distortion three way design; besides it's relatively unique shape, the key design points were the use of only underhung motor drivers (the lowest distortion type motor, if properly done), and pure pistonic operation for all drivers (a standard Avalon feature since day one). The Isis uses an Accuton diamond tweeter, the C173N-6-90 midrange (as it's currently numbered/known) which uses a massive neodymium motor with underhung construction, and custom Eton woofers using a Neodymium motor with underhung construction. Underhung means that the motor gap is larger than the voice coil, in fact, it must be by an amount equal to the voice coil length plus the positive and negative Xmax. This is quite difficult to do in practice, as it requires large pole piece assemblies and an EXTREMELY power magnet system. As in, expensive. But the elimination of inductivity modulation during the normal VC travel range cannot be argued with in terms of benefits- woofers built this way actually have decreasing distortion with increasing frequency above the impedance minima, unlike most drivers. This should be the case, considering decreasing cone travel, but is offset in many drivers by rising inductivity modulation in a conventional motor and VC assembly.

Tony Gee's Galactica uses more conventional drivers, but plenty of radiating area, to get good dynamics and SPL. Like the Wilson Audio X1-SLAMM from the 90's, he combines a 12" woofer and 15" woofer in the bass cabinet, instead of using two identical woofers. The size of the cabinet would not support a reasonable T/S alignment of two 15's, so this is a reasonable alternative, other than for having a 15" woofer, his measurements of the system response show maximum output at about 70 Hz in the bottom end, then a slow roll off to 40 Hz, and much faster below that - this is likely the effect of the cavity tuning for the 12" and the 15" and their in box Fb.






The woofers are a 15" Ciare NDH 15-4 in 60 L closed box, with a PHL 4531 ported in a net volume of 60 L. Both are paper cone woofers.

The midrange for the Galactica is the PHL1130, a paper coned 6-1/2" driver which is used in some professional monitors. Though PHL gives very detailed T/S and other specs, they don't publish response curves in their data sheets. Linear Xmax is 2 mm. This probably helps it achieve high sensitivity with a fairly conventional looking magnetic structure.

The cabinets were built for Tony Gee by Ruud Toto from the Netherlands. They are made of MDF in various thickness.

The tweeter is the well known Seas T29CF Crescendo tweeter, with higher sensitivity and output level capability than the original T25, but not as smooth a response or as nice off axis response. as the T25CF. However, it is about 4-5 db more sensitive, and that was undoubtedly necessary to mate up with the other drivers sensitivity.

My personal take is that the Galactica leans more towards the school of thought in moderately high sensitivity pro monitors, undoubtedly with good dynamics and sensitivity, but not the last word in smoothness, off axis polar response, or distortion.


My project, the Isiris, follows as closely in the Isis foot steps as is feasible in some important regards, and deviates with deliberation in some others.

The midrange is the same low distortion high sensitivity, unfortunately now rather expensive 6-1/2" Accuton C173N-6-90.







The Accuton tweeter was nearly impossible to source, so I took a chance on the Jantzen JDT-1024 diamond tweeter which I could source directly and which I'd also heard previously in some commercial systems.



I found that my memory of it's remarkable off axis behavior from listening to two systems with it was justified by measurements; it uses a thin acoustic diffuser to improve the response normally achieved with 1" hard dome tweeters. With my own measurement system which only goes up to about 46 kHz, I cannot measure any HF break up mode, so I have to say I'm quite pleased with the performance of the JDT-1024.




Woofers are the Aurasond NS12-513-4a; I've bought a number of them and it's smaller 10" brother after measuring one of the 12's years ago; it has a very well designed cone system and motor; the break up on the cone is at ~2.3 kHz, and not that high a Q; the motor is a neodymium underhung design, with low distortion falling steadily all the way up to 1 kHz.






The system development is documented rather loosely in the "Three Way 12" Design Study" thread, but will get a separate build thread some time soon, probably around Xmas, when it's actually fully finished with an updated construction installed internally, and some other cabinet modifications are completed.






While the original Avalon Isis is constructed also of MDF, the Isirs is constructed solely of LBL Bamboo- laminated bamboo ply, which is far, far stronger and stiffer than MDF. A 2-4" wide board of 3/4" MDF can easily be snapped across your knee; you will hurt yourself very badly trying to do that with LBL ply, and it won't even annoy the bamboo... :W

[bigg]

Galactica? NO it's ISIRIS!

Beautiful woodwork on the Isiris!

I have a thread on PE forum where I started building a Galactica inspired cheaper project for me. It uses MDF and plywood. the front baffles have an inner core of plywood just to have something more for the screws to "bite into". I haven't posted on that thread in awhile because of other projects that came up.

The fronts will be textured black and the sides will have slats of Hickory. I hope it comes out decent. I don't have the skills that a lot of you have ;x(. But hopefully it won't be too bad.

The thread is called "Galactica II".

After reading this thread, I had thought of at least redoing the front baffles with the bamboo and baltic birch. But those woods would be more expensive than my drivers! (old Vifa PL s and Seas Exell tweeter.)

Anyway, I'll be building a great system designed by you as best I can. I love the Accuton C173N 6 90 (?) the round one in the Isiris. also it's easier to do round holes (to me anyway.)

[bigg]

Would these be round alternatives to the C79, C173-6-191E, C173-6-95E and the C173-6-090? The last one is too expensive at over $900.00 apiece! But the other two are close to the C79 in price.

[JonMarsh]

The "round ones" I use are the C177-6-90. Unfortunately, current price considered, (due to Chinese restrictions on rare earth exports), that is the one that by far works and sounds the best. It is what is used in the Avalon Isis and several other high end commercial systems, and is what is in the Isiris.

I have purchased and tested some of the others, like the -95, and they don't cut it.

Look at the 95E distortion plot in comparison:



Unfortunately, it is quite audible (to me, anyway) and rather spoils things. I tried to use this in the "original" version of the Isiris for ThomasW, which was a dipole system; he didn't want to spend the bucks for the more expensive -90, though it was less expensive then (about $500), but I never could get the midrange transparency I was hoping for.

The -191 doesn't fare any better.




Now, the C79 doesn't have the sensitivity or output capability due to lower Sd, but the distortion within reasonable operating parameters is also quite good:



I bought and tested several other Accuton drivers in that form factor, like the C88 and C89, and they didn't "cut the mustard" in my book. The C79 is "it" for that class.

I've had hopes for the C90-6-724 Cell 5" midrange, but it's about $600, and seems to have some design issues -



The high Q peak (for an Accuton) seems to contribute to distortion resonance amplification, and they don't explain what they mean by an unfiltered and filtered distortion plot- I'd normally go by the unfiltered.


Unfiltered Distortion




If that really isn't a problem, then it's a somewhat promising looking driver, though again, the sensitivity is only about that of the C79, nowhere near the C173-6-90 I prefer.

[bigg]

Thanks Jon,

If I had the money, I would build the Isiris. I'm afraid the C90 is just too expensive for me. also i tried to locate the Aurasound woofers at Madisound and they don't have those anymore (or the smaller Aurasound woofers I have in the first towers I made a few years ago.)
And I think you mentioned on Avalon Isis that the Eton woofers were special made items for Avalon.(?) So I guess I'll just have to be very careful when I do the square cutout for the C79.

[JonMarsh]

I built a special jig for that and used a door jamb rebate router bit to cut the rebate for the C79. Worked OK, but it wasn't trivial!

[bigg]

I was looking at a router bit set by an Italian company at my hardware store. It was for cutting rabetts and it had different diameter "rollers" that you put on it to get different rebates. I was thinking of getting this set but it runs about $50.00 at the hardware store. I'll try to find it online somewhere.

[JonMarsh]

OK, some hints from the past: Routing the rebates for the C79 midrange driver, simple fixture:




And my own distortion measurements of the C79:

[bigg]

Thanks Jon,

I didn't mean to make you redo stuff from earlier posts. You are pressed for time as much, or more, than I. I believe you about the C79. I just think the C90 in the Isiris looks so much nicer! I'm going to have to spend some more time reading the discussion on that post. (just for fun.) the router bit set I was looking at is from CMT.

[meb46]

I must add, even though the C173-6-090 is apocalyptically expensive, it is worth every penny. I used this driver the same as Jon in my MIC project... and I can't fault it. In fact, I think the mid range in the MIC setup is fantastic and makes the overall speaker. Clarity of vocals are phenomenal. Granted, its too expensive for the majority of us, but... if you are going to the trouble of making complex big three ways like the Galactica, Isiris or MIC, DONT short change your efforts and time by opting for a cheaper driver... These types of speakers take a MASSIVE amount of time to complete (Mine are in excess of 18 months, more like 2 years), so why the effort if you aren't going to back up your efforts with the most applicable drivers.

I will be posting my thoughts on the MIC's shortly, but in short... HUGE, Hugely Time consuming, Hugely heavy to move around, Hugely expensive for a DIY Project... but... Hugely happy and its been worth every drop of sweat and penny along the way. Very Happy. My mine is already running away to version 2 and how I can make them better...

[meb46]

Jon, between you and I, how long is it going to take to convince the members of the forum to build the next Isiris/MIC?

[JonMarsh]

Jon, between you and I, how long is it going to take to convince the members of the forum to build the next Isiris/MIC?

Interesting question... let's see, completing whatever it is you call the MkII update (crossover tweaks in progress for me!) then sponsoring guided tours and listening sessions in Chicago and the SF Bay area? Of course, our significant others may have some inputs about that...

[bigg]

So, what we would really love;

Ardent w/
ScanSpeak Illuminator D3004/6640-00 tweeters
Accuton C173-6-90 mids
Dual ScanSpeak Illuminator 18WU/8747T-00 woofers

My wife doesn't like the square C79s. She says I should save up to get the better drivers. It will take a long time anyway.