Three Way Evil Design Study

[Evil Twin]

Accuton C89 Basic Measurements

The C89 is the higher Xmax brother of the C79 with a longer voice coil, slightly heavier diaphragm without the ears, and a larger rear window with the magnet further back.


SPL-Phase




HD2



Clearly suggesting no more than a 2 kHz crossover


HD3




HD4



On the balance, this data suggests an upper crossover no higher than 2 kHz. In comparison to metal cone midranges, their is a benefit in a simpler crososver without the need to suppress a high amplitude break up, but though the cone is more self damped, there are still phenomena associated with the hard cone which dictate a lower crossover point.

A brief look at higher levels didn't show significant rise in distortion until above 100 dB; the distortion shown here appears to be a matter of basic motor symmetry and flux linearity.


I do not think the Emperor is completely satisfied with these results... I see a faint nimbus of blue lightning discharges playing along his fingers as he sits... Undoubtedly it would be wise to find something do to elsewhere from his presence...

[capslock]

Hmm, I loose track of which Thiel driver is which, there are probably as many models as drivers manufactured. Wasn't the C89 the new one with the neo magnet?

The C79 is pretty good with 60 dB 2nd harmonic headroom, the C89 is clearly worse.

Both have broad third harmonic in the midrange -- this could indeed be Le asymmetry.

I am really puzzled by these forests of all kinds of harmonics from 4 kHz up. This looks just like a ringing metal cone -- harmonics amplified by peaks in the frequency response, except that the FR looks well tamed...

[capslock]

Did you annect new lab space, or did you earthly host move into a new appartment?

[Evil Twin]

Hmm, I loose track of which Thiel driver is which, there are probably as many models as drivers manufactured. Wasn't the C89 the new one with the neo magnet?

The C79 is pretty good with 60 dB 2nd harmonic headroom, the C89 is clearly worse.

Both have broad third harmonic in the midrange -- this could indeed be Le asymmetry.

I am really puzzled by these forests of all kinds of harmonics from 4 kHz up. This looks just like a ringing metal cone -- harmonics amplified by peaks in the frequency response, except that the FR looks well tamed...

The C89 is the successor to the C88, and is on the same basic frame as the C79, but doesn't have the ears, and has about 60% greater depth between the front plate and the rear plate mounting the magnet system. It has a higher Xmax, with a different surround system, also. It's used in some speakers like the Talon Audio Firebird as a midrange.

The C90 (old number) is a 7" driver, with about the same operating range as the C89, but much greater Sd, higher sensitivity (~93 dB), and fairly low distortion even at 105 dB output (@16 watts) in it's intended operating range (250 Hz to 2.5 kHz).

Yes, the ceramic cones have some unusual operating characteristic; my belief is that this driver would be best served with another of those CE type filters, no higher than 1.8 to 2 kHz. Any higher and the distortion amplification would be unacceptable. Disappointing to a degree, but it is likely that still useful results can be obtained. The main benefit compared with some other candidates like the W15CY is the lack of high level breakup modes requiring extra attention, and a cone shape that is less prone to flexing before the final breakup.

The Imperial corporate labs were moved and setup again over the last two weeks, resulting in an unusual personal schedule, requiring even earlier rising time than usual.

(Vader? Yes, my master. Rissse......). Disruptive of productivity in other matters...

[ssabripo]

Yo Evil....uhm, I mean.... Dear Dark Lord, any updates on the cabinet and alignment? you had mentioned you were gonna have something concrete to share by the end of jan.

we anxiously await some info/teasers... :T

[ssabripo]

this thread shall not DIE!!!

[Evil Twin]

Yo Evil....uhm, I mean.... Dear Dark Lord, any updates on the cabinet and alignment? you had mentioned you were gonna have something concrete to share by the end of jan.

we anxiously await some info/teasers... :T

You are advised to have more patience than the Emperor does...

The cabinet CAD drawing are well under way, but not complete. As previously stated, the basic design will/can be used for both the M10ta and M12ta, and the middrange cabinet will use a removable front plate (aircraft aluminum) to facilitate a selection of midrange drivers, depending on the budget and desires of the constructor.

Perhaps this should be designated the Modula-ta, for the modularity and flexibilty of the design. Bass cabinet height and overall height have been finalized, as well as enclosure volumes. Driver measurements for crossover design are about 40% complete.

All will be disclosed at the right time...

[mmoeller]

Patience... we all know what happens when your come out of lightspeed to early....

[Evil Twin]

With regards to the proposed low frequency alignment, these plots should be sufficiently informative...







With a nominal room boundary lift of 6 dB in the low freqeuncies, in room response per cabinet at 1meter will comfortably extend to 20 Hz at over 106 dB. Perhaps not capable of reproducing the full effect of the main drives of a fleet Stardestroyer as heard in the engine room, but it should be sufficient for most music applications.

The 76 liter bass enclosure will have a width of 14.5", a net cabinet height of 36", and a depth at 90 degrees to the front or rear panel of 18". The midrange unit has a net height of ~ 16", for a total height of ~52".

This partial screen shot should convey the concept....

[ssabripo]

excellent news indeed!!

[ColoradoTom]

Considering the estimated time that the design will be finished.... perhaps we sould call this version Pisces.......... or perhaps Pisis!! 8)

Verb form:
pisis (past tense of pisi)

pissed
Retrieved from "http://en.wiktionary.org/wiki/pisis"

Name would probably fit a certain manufacturer!! :rofl:

Tom

[JonMarsh]

Yeah, Pisces sounds like a good idea! At the rate Evil Twin is going, I suspect this will be done long before it occurs to a certain Boulder speaker manufacturer that the real market might be in an Isis Junior? Considering the upgrades possible with newer drivers? I'm sure the new neodymium unhderhung Eton woofers in the Isis are a significant step up from the older Eton's, but then the NS12-513A will wipe the floor with the Eidolon class Eton wofoer, too. At least on paper these guys go all the way down to 18 Hz at pretty serious levels in a moderate size room.

So, yeah, Evil Twin SHOULD listen to your suggestion- a Pisces as a Petite Isis?

Of course, that may be partly why there's an Eidolon Vision now, which one (someone?) presumes is an update of sorts to the original Eidolon, considering the name change? Though there is nothing obviously different, unless there are some crossover upgrades or tweaks to the Eton woofer.

Life is interesting...

[jkrueger]

Modula-ta

Will the M10ta be a 2 piece cabinet too?

Thank you for the details. I have been dreaming of these since post #1. ;x( ;x( ;x( ;x( ;x( ;x( ;x( ;x( ;x(

Jon

[Evil Twin]

This is the idea- one cabinet design to fit variable configurations. It is a function of the RS270 wanting a rather large volume for good performance, and the possibility of mix and match upper end, though with the necessary adjustments to the crossover. The M10ta design will be prepared with the RS270 for both the C89 and the TB W4-1337. Unibox calcs for the RS270 will be posted sometime this weekend.

[JonW]

Evil Twin-

I'm trying to understand some aspects of your design philosophy for this nice project. As part of my education. Why are you only using one woofer? In general, TMWW seems to be a lot more popular of a design than TMW. Probably because a second woofer adds that extra oomph that most speakers can't produce. Might it be because you don't want to increase the cabinet volume? Or because of the cost of adding another driver? Maybe because the Aurasound 12" is 4 ohms and 2 of them might get to be a little troublesome? Maybe because this one woofer will have enough output on its own?

I like that you found a nice, low distortion woofer. (And one that plays high, to boot.) For my MT project, I'm seeing that picking the right drivers is far from obvious. (I was leaning toward a Scanspeak 18W8531 woofer but an impedance warble around 1000 Hz is giving me pause). Your testing for this 3 way project will give me some good ideas to work with if my MT project goes well and I decide to try a 3 way. Thanks.

[Evil Twin]

Evil Twin-

I'm trying to understand some aspects of your design philosophy for this nice project. As part of my education. Why are you only using one woofer? In general, TMWW seems to be a lot more popular of a design than TMW. Probably because a second woofer adds that extra oomph that most speakers can't produce. Might it be because you don't want to increase the cabinet volume? Or because of the cost of adding another driver? Maybe because the Aurasound 12" is 4 ohms and 2 of them might get to be a little troublesome? Maybe because this one woofer will have enough output on its own?

I like that you found a nice, low distortion woofer. (And one that plays high, to boot.) For my MT project, I'm seeing that picking the right drivers is far from obvious. (I was leaning toward a Scanspeak 18W8531 woofer but an impedance warble around 1000 Hz is giving me pause). Your testing for this 3 way project will give me some good ideas to work with if my MT project goes well and I decide to try a 3 way. Thanks.

There are many possible paths to the achievement of any objective; through the careful definition OF the objective, the best path may emerge through a combination of Force intuition and critical review.

You appear to be already developing this technique, though only a Padawan learner at this time. You already see that picking the right drivers for the parameters which are truly most significant to you is no easy matter. There are many factors that can be considered and balanced off against each other; in many cases there are several paths to similarly musical systems, but with somewhat different strengths and weaknesses.

Multiple drivers contibutes primarily to Sd, radiating area, which is one factor (an important one) in achievable SPL. Xmax is the other, but it must be remembered that high Xmax drivers often bring with them other drawbacks, such as high Le, contibuting to inductivity modulation and distortion in the upper bass and midrange, at the point when one would expect reduction in cone motion due to rise in frequency to be decreasing distortion.

Another reason for multiple smaller drivers is to counter the issues arising with many larger drivers, such as cone break up within the intended operating range. For this reason, it may be preferred to run with two 10's or two 8's instead of one 12, considering the characteristics of mundane drivers.

But the MXXta series of speakers is not about mundane.

What are they about?

To summarize briefly, to realize wideband high performance reproduction at moderate playback levels through optimization of enclosure and crossover design- to extract the best level of performance possible for a monopole speaker within the chosen driver budget and complexity level.

There may be other motivations, but these are the ones I choose to discuss in a public forum.

They are not all out cost-no-object designs. In fact, they have a relatively low component cost compared with "sweat equity" requirements.

Compared to the "smaller brother", the intention behind the M12ta, or "Picses", is to provide quite seemless playback performance in the range of 18 Hz to 25 kHz, at peak SPL's up to or somewhat beyond 106 dB accross that range. And to do so at a still "manageable" cost and complexity, and with a reasonable balance of non-linear and linear distortion, including minimization of cabinet vibration related issues.

In the case of the M12ta, the LF design is a function of desired enclosure size (no more than 80 liters), preferred bass extension to below 20 Hz in room, SPL capabilities from 18 Hz up, and low linear distortion to 1 kHz giving some flexibility of midrange crossover. The 4 ohm Aurasound gives a sensitivity advantage considering the impact of the long throw design for a woofer. Two in parallel would require wiring the drivers in series, which would not drop the sensitivity, but also would not increase it- though it would up the SPL capability.

However, the single Aurasound in this cabinet design is capable of twice the acoustic output of the woofers used in an Eidolon and nearly the same realtionship to the larger Eton 12-680, the only 12" Eton available to the DIY constructor. It is also lower distortion than either of these drivers, due to it's more contemporary motor design. Given the limitations of the more moderate cost midrange and tweeter drivers, using two woofers in this system would result in unbalanced capabilities, unless other changes were made, which would substantially increase the cost. Should a Picses II exist with dual woofers? And a larger Accuton midrange? And a higher performance Accuton or other tweeter? An interesting question for the Emperor to ponder- but one that would result in a very significant increase in cost, probably doubling or more. Diminishing returns are of concern even to a Sithlord.

It is by no means intended to be a definitive solution- I build these at my own pleasure, or that of the Emperor's. I encorage anyone to take the information and experiences reported here, and find there own path in the Force- this is the "Y" in DIY. There are other aspects I do not have the time today to discuss guiding other design decisions- ultimately it is not always a black and white decision, but a shade of gray and which problem or issue can more easily be dealt with using the techniques you are comforable with.

In the end, it is about the music, though- does it bring fidelity and involvement to the intent of the music you listen to?

[JonW]

Evil Twin-

Thanks very much for insights on your thought process. That does help me understand things a little better. And the Aurasound sounds pretty special.

I’m at the beginning of my learning, but it’s quite interesting to see how many ways there are to achieve one’s goals. Not to mention how so many people have such different goals.

Like you, the “sweat equity” is tough to come by for me. So I’m trying to do as much reading and thinking before ever starting the actual construction. As we say to our graduate students: “A day in the library will save you a month in the lab.” [Although they often respond with “Yes, but a month in the lab will save you from a day in the library.” ]

It’ll probably take me a few projects before I have perspectives on what tradeoffs I’m OK with and which ones are not negotiable. At the moment, I’m biasing my choices toward very low distortion drivers. And for the cabinet design I’m looking at how to minimize diffraction, thereby increasing the perception of pinpoint clarity from a speaker.

But we’ll see where things go. Thanks again.

-Jon

[jkrueger]

Mix and Match

Evil Twin....Sir

Pardon the interuption of your weekend full of inter-galactic conquest, but will you be designing the M12ta with two different tops as you have said is your intention for the M10? And I have been wondering.....How does the RS270 measure up against the Aurasound NS10-513-4A. It is clearly less expensive, but in your opinion how much performance, if any, is sacrificed by going with the Dayton driver?


Hoping the Star Destroyer is firing on all cylinders


Jon ;x( ;x( ;x( :dancenana:

[rjr1]

Should a Picses II exist with dual woofers? And a larger Accuton midrange? And a higher performance Accuton or other tweeter? An interesting question for the Emperor to ponder- but one that would result in a very significant increase in cost, probably doubling or more. Diminishing returns are of concern even to a Sithlord.

Evil Twin,

I think that it should be designed both ways. The Pisces II should definitely be considered an option. :T
I would like to see the design with 2 12"Auras and the Accuton C90-T6 and perhaps the Accuton C24-6 tweeter. If the outcome was promising I would be on standby with the troopers to start the cabinet construction.
Also, I know it would be costly but what about the NS12-794 with the underhung VC? :idea:

[Andy_G]

Why is Gaff tape like "The Force"

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cos it's light on one side, dark on the other side, and holds the Universe together !!

[Evil Twin]

Evil Twin,

I think that it should be designed both ways. The Pisces II should definitely be considered an option. :T
I would like to see the design with 2 12"Auras and the Accuton C90-T6 and perhaps the Accuton C24-6 tweeter. If the outcome was promising I would be on standby with the troopers to start the cabinet construction.
Also, I know it would be costly but what about the NS12-794 with the underhung VC? :idea:

Because of the modular construction planned for the midrange enclosure, the C90-T6 (the old Accuton part number for that driver) can be measured and included as an option. It's greatest advantage over the C89 is the ability to play louder, with lower overall distortion. A duel NS12-513A crossover desgin will be published, with the C90-T6, but probably not built in the Imperial labs- this is where the "Y" in DIY comes from.

What you call the C24-6 is now known as the C30N.

The Aurasound NS12-513A has an underhung VC, low distortion, and excellent cone behavior for a 12" woofer. It is a woofer, not a subwoofer.


The Aurasound NS12-794 is a subwoofer, with greater Xmax, a less well behaved cone, and 5 dB lower efficiency. It does not meet the system goals for a three way speaker design, especially not sensitivity.

Regarding the Aurasound NS10-513A, it offers no significant cost advantage over the NS12-513A, but a sizeable Sd disadvantage, so I consider it a non-starter for a M10ta.

The RS270 is moderately efficient and requires a large enclosure, the same size as planned for the M12ta/Picses, but the cost is very reasonable for the budget constructure. The cone perfomrance is not as good as the Aurasound, but the cost is 1/3, a very substantial reduction. The focus for what is now called the M10ta is getting as close as possible to the same level of extension and resolution at a far lower driver cost target. The finished system will require a high sweat equity component, but as modest material cost as is possible. Other options to the design will be discussed at the appropriate time.

[TurboFC3S]

Hoping the Star Destroyer is firing on all cylinders

Ha! Obviously the Star Destroyer runs on rotary power!

[cjd]

I believe (don't quote me on this) that the RS 3-ways I've done can get away with only a single RS180... Now I have to go mess with that concept. :P

C

[rjr1]

Because of the modular construction planned for the midrange enclosure, the C90-T6 (the old Accuton part number for that driver) can be measured and included as an option. It's greatest advantage over the C89 is the ability to play louder, with lower overall distortion. A duel NS12-513A crossover desgin will be published, with the C90-T6, but probably not built in the Imperial labs- this is where the "Y" in DIY comes from.

This is good news. :B

I concure with the driver selection provided but I am not sure why Madisound has them both listed as subwoofers.

If the Imperial Labs will not be building them someone will have to. Dual 12's and the larger Accuton drivers sounds good to me.

[ColoradoTom]

If the Imperial Labs will not be building them someone will have to. Dual 12's and the larger Accuton drivers sounds good to me.

I'll be happy to take this on.... told the wife I didn't want a Christmas present this year, just wanted to be able to build some speakers this summer. She told me I have a budget of up to $5000.00 after listening to the M8ta's. :E

The only catch is that I have to build writing desks for both of my daughters (Arts and Crafts Library Table design for you woodworking types) with matching chairs and she wants a "game" table for our family room made with a Santos Rosewood inlayed top.

Looks like I'll be making a LOT of sawdust this summer!!

Tom

[chasw98]

The only catch is that I have to build writing desks for both of my daughters (Arts and Crafts Library Table design for you woodworking types) with matching chairs and she wants a "game" table for our family room made with a Santos Rosewood inlayed top.

Looks like I'll be making a LOT of sawdust this summer!!

Tom

Tom:
The same thing happened to me. After my last project she said she wanted the kitchen cabinets redone, but after that I have my eye on a set of the 12ta's. If I start building when you do, I can definitely learn from your tricks and tips.

Chuck

[ColoradoTom]

Tom:
The same thing happened to me. After my last project she said she wanted the kitchen cabinets redone, but after that I have my eye on a set of the 12ta's. If I start building when you do, I can definitely learn from your tricks and tips.

Chuck

Well,

I don't know how many "tricks" I'll have, but I know I will document the process much more than with the M8ta's. Jon did such a good job of documentation with the M8ta design that I didn't feel the need - but if I'm working on something new I kinda feel I should repay what I was given the first time around.

PS - Don't watch woodworking shows while your wife is in the house - while watching Woodworks hosted by David Marks my wife got the idea for the tables for my girls as well as a hall table for our front entryway (see pictures). The hall table is on hold until Fall.

Tom

[rjr1]

I'll be happy to take this on.... told the wife I didn't want a Christmas present this year, just wanted to be able to build some speakers this summer. She told me I have a budget of up to $5000.00 after listening to the M8ta's. :E

The only catch is that I have to build writing desks for both of my daughters (Arts and Crafts Library Table design for you woodworking types) with matching chairs and she wants a "game" table for our family room made with a Santos Rosewood inlayed top.

Looks like I'll be making a LOT of sawdust this summer!!

Tom

I am glad to see that someone else shares my interest in the larger design.
This will be a very interesting summer indeed.

[tyler]

Because of the modular construction planned for the midrange enclosure, the C90-T6 (the old Accuton part number for that driver) can be measured and included as an option. It's greatest advantage over the C89 is the ability to play louder, with lower overall distortion. A duel NS12-513A crossover desgin will be published, with the C90-T6, but probably not built in the Imperial labs- this is where the "Y" in DIY comes from.

This is an excellent plan. I also like the Picses II idea. Looks like we are going to have our work cut out for us.

[tyler]

This is good news. :B

I concure with the driver selection provided but I am not sure why Madisound has them both listed as subwoofers.

Aurasound also has the NS12-513 and the NS12-794 listed as subwoofers. However, because of the longer throw on the 794 it may not perform as well......
The frequency response also differs slightly.

[audioslave]

Just subscribing to the thread!

My friend just completed a set of the Nat Ps and they sound phenomenal. I have been reading the test results of the RS drivers and tweeters from Mark K with much interest since I built an MTM that used Vifa PL18s and SS9500. It sounds great, but it’s clear that you can get better performance for less money these days. This project looks great, If I’m going to go through the effort of constructing and finishing some heroic cabinets…..this looks worth while!

Mike

[---k---]

PS - Don't watch woodworking shows while your wife is in the house - while watching Woodworks hosted by David Marks my wife got the idea for the tables for my girls as well as a hall table for our front entryway (see pictures). The hall table is on hold until Fall.

Tom

Yeah, that is a good one. I've just started watching it. I like the fact that he isn't afraid of breaking out a router. He does advanced projects with the easiest methods, rather than being a purist woodworker like so many.

[ssabripo]

Dark Lord...there is treachery lurking. The intergalactic trolls have intercepted transmission of the completion of Avalon Eidolon clones, extremely similar to the Isiris form.

http://homepage.mac.com/marc.heijligers/audio/milestones/cabinet/construction/construction.html

Image not available

[Evil Twin]

Dark Lord...there is treachery lurking. The intergalactic trolls have intercepted transmission of the completion of Avalon Eidolon clones, extremely similar to the Isiris form.

http://homepage.mac.com/marc.heijligers/audio/milestones/cabinet/construction/construction.html

Marc's project was discussed in some length about a year ago on HTGuide, with participation and questions from Mark-

His project by drive configuration is equivalent to an Opus Ceramiqe, not the larger Eidolon. He has had several crossovers designed by others, which he has built; his budget limitations have prevented using preferred components (ferrite core inductors and electrolytic capacitors should be avoided, and are not used in even a "starter" system like the NatalieP). These crossovers were often designed by constructors favoring low order serial networks, which is not a configuration that will work well with the Accuton drivers, which require some care to keep them out of the "edgey" range above 3 kHz.

A point apparently lost on some is that the usable bandwith must include the transition zone, not just the nominal passband.

He also did not use the traditional ultra rigid Avalon front panel design, but made some reasonable tradeoffs with a baffle design about half to 1/3 as thick.


Image not available


Even this thickness of baffle is problematic with the 79 midrange, due to it's very limited rear window. Undercut baffles at the least are necessary, though I believe a separate plate mounting will be better.


Image not available


Marc's system with an optimized crossover may offer better midrange performance at higher SPL than the M8ta, but it does so at far, far higher cost.

That expense in drivers in the upper range should be matched with comparable performance in the low range, not just a single 8" woofer.

[tyler]

Dark Lord yet another attempt has been made. This time with the larger Accuton drivers and the Eton 12". I felt reporting this to you was of the greatest importance. However, this should be no match for the 3 way design with a seperate enclosure housing the tweeter and midrange. In addition, if one chooses to build the dual woofer unit like myself they will truly have something special.



It appears they may be trying to improve the baffle construction.



The completion.



Here is a link to the project for your review.

http://www.htforum.nl/yabbse/index.php?topic=29910.0

[Evil Twin]

Dark Lord yet another attempt has been made. This time with the larger Accuton drivers and the Eton 12". I felt reporting this to you was of the greatest importance. However, this should be no match for the 3 way design with a seperate enclosure housing the tweeter and midrange. In addition, if one chooses to build the dual woofer unit like myself they will truly have something special.



It appears they may be trying to improve the baffle construction.



The completion.



Here is a link to the project for your review.

http://www.htforum.nl/yabbse/index.php?topic=29910.0

Most interesting... it should have somewhat higher bass output capability then the 11-580, but the result esthetically is less than a complete success- more on the order of a pregnant Eidolon, I would say.

Also, I recall from past efforts that that woofer height can be problematic due to floor bounce in it's operating range at common listening distances.

Still, a most worthy effort to be commended, and with very professional fit and finish. :T

It would appear that constructing Avalon Klones is a national pastime in the Netherleands, judging from the number of documented examples.

[jkrueger]

Deep sigh....

This thread is getting so far down the list that I am considering taking some depression medication. I am an impatient turd. :cry: ops: :cry: ops:


Okay...Okay...I am not really depressed.

[Jed]

This thread is getting so far down the list that I am considering taking some depression medication. I am an impatient turd. :cry: ops: :cry: ops:


Okay...Okay...I am not really depressed.

You could always start building your cabinets now based on one of the designs above. Or, get the M8ta box started, as I think Jon plans on updating that one to a 3-way as well. Don't forget the Y in DIY- that's the most fun! :T

[ColoradoTom]

I'm working on some DIY acoustical treatments while I'm waiting for Jon to work out the design - might as well get the room in the best possible condition if I'm going to take on this new challange. Attached are two pictures from my workshop of a 2-D diffusor that is similar to the RPG Skyline product (which is the third picture). I've used cedar as the wood because it's light (and smells REAL good). I purchased the cedar in a rough form and I had to plane and cut the pieces which took about 2 hours prep and about 1/2 hour to cut the individual blocks. Total cost so far is about $22.00 US. The array is 18 inches square and should be effective in the range of 900 to 4600 Hz. This is just a prototype to see how the process will go, I'll need about twelve of them and they will be combined with six 2 foot by 4 foot bass traps spanning corners and made with rigid insulation that I pruchased a few years ago.

Had six guests over for a party last weekend - nobody could believe that I actually made the M8ta's. Every single person sat in the audio room for over 5 hour listening to music. It was like musical chairs as everyone tried to sit in the sweet spot - lots of fun!!

Tom

[TacoD]

Tom,

do you also have a website which describes the construction/ calculation of these? I should have it somewhere in my bookmarks, but cannot find it anymore (website has some calculators to optimize for a certain frequency band).

Taco

[ColoradoTom]

Tom,

do you also have a website which describes the construction/ calculation of these? I should have it somewhere in my bookmarks, but cannot find it anymore (website has some calculators to optimize for a certain frequency band).

Taco

Taco..... here you go.

Calculator:

http://www.mhsoft.nl/DiffusorCalculator.html

Construction (this link shows a rather simplistic and not very attractive method using precut material - I made changes by ripping cedar/redwood stock into perfect 1.5 inch material to use for the blocks.):

http://www.pmerecords.com/Diffusor.cfm

I've made 1-Diffusors in the past.... these seem to work much better. I'll be cutting up more boards today and then I'll be spending the next several weeks gluing things up.

Tom

[TacoD]

Thanks Tom, really appreciated.

[chasw98]

This thread needs to be brought back from the dead, so I am bumping it. I am also getting ready to spend my pennies on a pair of the Aurasound NS12-513A's in anticipation of building this design. (It helps spread the cost over a period of time if I buy a little here and a little there) (We all do not have the budget of the Emperor!). They are listed in Madisound as NS12-513-4A. Which I assume means a 4 ohm version. Are these the drivers being proposed for the low end of this design?

Chuck

[tyler]

This thread needs to be brought back from the dead, so I am bumping it. I am also getting ready to spend my pennies on a pair of the Aurasound NS12-513A's in anticipation of building this design. (It helps spread the cost over a period of time if I buy a little here and a little there) (We all do not have the budget of the Emperor!). They are listed in Madisound as NS12-513-4A. Which I assume means a 4 ohm version. Are these the drivers being proposed for the low end of this design?

Chuck

Yes, those are the Aurasounds that were tested and recommended. I have stocked up on the Accuton c24-6 (C30N-6-24) and C90-T6 (C173N-T6-90) for this project. I have a pretty good budget for this so I may go with the Eton 12-680 Hex woofers. My design will include 2 woofers per side.....
For price versus performance though, you really can't beat the Aura's.

[JoshK]

I thought in the previous posts that the C90-t6 was ruled out due to the limited HF and that the leaning was towards the C79 or C89. With the Etons, do they have low enough HD and enough xmax to be viable?