Tarkus being "civilized" for acceptance by spouse

[cowtown]

Hi All,
Working under the premise "it's better to beg forgiveness than to ask permission," I bought all the drivers and components for a set of the Carmody Tarkus(es). I've really wanted to build them since he published the design.

My wife has strongly encouraged me not to build the stock design, citing reasons of home decor and whatnot (please don't be offended Paul Carmody - I think the design is really cool). She is willing to compromise on a one-piece design with roundovers and curves.

Working under the assumption that my options are to "civilize" the Tarkus design or not to build them at all, I'm asking for some help and suggestions about a cabinet with a tapered (narrowing-width) baffle that will still be as true as possible to the original design.

Below I've attached a SketchUp models of:
1) the stock two-piece Tarkus cabinets
2) a proposed curved-cabinet design
3) draft measurements of the proposed tapered baffle

For the curved cabinet, I've kept the driver spacing, mounting positions, and box volume as spec'ed in the two-piece design. The curved cabinet will be a few inches taller, which from what I understand is an OK thing to do(?).

I'm hoping that the only sticky problem that needs solving here is whether it is possible to do a curved baffle, and also stay relatively true to the design's original baffle widths. I understand that there may be crossover/EQ tweaks needed, but would like start out with the as-designed crossover if at all possible.

Is there a way to calculate the proper widths for a tapered-width baffle so as not to mess up BSC and frequency response too badly? My first stab at it (pictures #2 and 3) has been to keep the baffle widths at the mid-points of each driver the same as in the original two-piece design. For example, the edge-to-edge baffle width throught the center of the woofer is 13". But at the top edge of the woofer, width is down to 11.5" and it's a bit over 14" at the bottom of the woofer. I would also like to do a 3/4" roundover on the vertical edges of the baffle.

Am I on the right track? Is there a right track, or is this just a bad idea? I REALLY want a pair of Tarkus(es).

Thanks!

[cowtown]

Re: Tarkus being "civilized" for acceptance by spouse

I just realized that the top-of-cabinet dimensions are not consistent between the curved-cabinet picture and the baffle picture.

Please look at the baffle-only picture (#3) for the dimensions that I'm kicking around.

[donradick]

Re: Tarkus being "civilized" for acceptance by spouse

I am not an expert, but I think your new design is beautiful. I don't think you will have any significant issues due to your proposed baffles.

[gabel87]

Re: Tarkus being "civilized" for acceptance by spouse

I like the look of your design. I'm no expert either, but changing it to a flat-faced baffle will alter the design significantly imo. Iow, the tipped back woofer.

Also keep in mind the distance from the baffle edge to the drivers centers and the driver center to center spacing remains the same. Sounds like you know all that though and are asking the right questions of which I don't know either. I would assume that if the baffle width is the same next to the drivers, baffle step would be similar, maybe it depends on the amount of taper. Seems like where the largest necessary discrepancy will be is at the tweeter where it's obviously going to have to be narrower. Good luck. If you succeed those are going to be awesome.

[Pete Schumacher]

Re: Tarkus being "civilized" for acceptance by spouse

Aside from the change in acoustic offset of the woofer, where it matters least since the XO point is very long wavelength, the compromise on the baffle shape should keep the overall response very close to the original.

I really like the shape. Reminds me of my favorite speaker. No reason that couldn't be done, and if necessary, tweaked in the XO.

But if these are going to be used in a TV room setting, the AVR has all the EQ it needs to take care of whatever small changes the different baffle shape might make.

[lunchmoney]

Re: Tarkus being "civilized" for acceptance by spouse

I like the look of your design. I'm no expert either, but changing it to a flat-faced baffle will alter the design significantly imo. Iow, the tipped back woofer.

I seem to recall Paul mentioning that the tilted-back woofer was for aesthetics only, and would work just fine if not tilted back.

[tomzarbo]

Re: Tarkus being "civilized" for acceptance by spouse

Hi All,
Working under the premise "it's better to beg forgiveness than to ask permission," I bought all the drivers and components for a set of the Carmody Tarkus(es). I've really wanted to build them since he published the design.

My wife has strongly encouraged me not to build the stock design, citing reasons of home decor and whatnot (please don't be offended Paul Carmody - I think the design is really cool). She is willing to compromise on a one-piece design with roundovers and curves.

Working under the assumption that my options are to "civilize" the Tarkus design or not to build them at all, I'm asking for some help and suggestions about a cabinet with a tapered (narrowing-width) baffle that will still be as true as possible to the original design.

Below I've attached a SketchUp models of:
1) the stock two-piece Tarkus cabinets
2) a proposed curved-cabinet design
3) draft measurements of the proposed tapered baffle

For the curved cabinet, I've kept the driver spacing, mounting positions, and box volume as spec'ed in the two-piece design. The curved cabinet will be a few inches taller, which from what I understand is an OK thing to do(?).

I'm hoping that the only sticky problem that needs solving here is whether it is possible to do a curved baffle, and also stay relatively true to the design's original baffle widths. I understand that there may be crossover/EQ tweaks needed, but would like start out with the as-designed crossover if at all possible.

Is there a way to calculate the proper widths for a tapered-width baffle so as not to mess up BSC and frequency response too badly? My first stab at it (pictures #2 and 3) has been to keep the baffle widths at the mid-points of each driver the same as in the original two-piece design. For example, the edge-to-edge baffle width throught the center of the woofer is 13". But at the top edge of the woofer, width is down to 11.5" and it's a bit over 14" at the bottom of the woofer. I would also like to do a 3/4" roundover on the vertical edges of the baffle.

Am I on the right track? Is there a right track, or is this just a bad idea? I REALLY want a pair of Tarkus(es).

Thanks!

I really like your proposed design.
I can't speak to the crossover specifics, as I don't have the knowledge, but I like your layout of the drivers and the basic overall look of what you propose. What's even cooler is that it shouldn't be all that hard to pull off. Multiple thinner layers for the sides should be easy enough to manage.

I think you have a winner!

TomZ

P.S. I like curves too.

[Paul Carmody]

Re: Tarkus being "civilized" for acceptance by spouse

Wow, that's a beautiful design.

My quick "thumbnail" calculations say that your proposed baffle width--its average, anyway--is close enough to the original that the crossover should sound the same as the original. Also, Pete is correct that the "tilted" woofer is just for aesthetics, and that the wavelengths are so long at those frequencies (about 3-4 feet around the XO point) that one definitely has some wiggle room in terms of aligning the acoustic centers of the drivers.

I hope your wife gives it the OK, because I sure like it!

[fastbike1]

Re: Tarkus being "civilized" for acceptance by spouse

Looks good. The top will give you some issues if you want it flat all the way across. If so, you probably want to solve that problem before the cab is assembled.

Any chance you would share the Sketchup drawing of the stock Tarkus? Very nice work there as well.

[gabel87]

Re: Tarkus being "civilized" for acceptance by spouse

I seem to recall Paul mentioning that the tilted-back woofer was for aesthetics only, and would work just fine if not tilted back.

I thought when designers tilted the baffle it was to merge the sound at a specific point in space. At what frequency does it not matter as much?

btw cowtown, I like the boat-like theme. Make a dbl ender and cut in half and you've got your cabs ;)

[DjDisturbed]

Re: Tarkus being "civilized" for acceptance by spouse

Those look like they will be a very nice build.

[Hunter12]

Re: Tarkus being "civilized" for acceptance by spouse

Facinating to see how design can alter the character of a speaker.

The neat thing with you plan is it's retained the bold character
of a powerful three way speaker but presented in a low key
elegant presentation.

Well done, were there is a will there is a way.

You give many of us hope.

[lunchmoney]

Re: Tarkus being "civilized" for acceptance by spouse

I thought when designers tilted the baffle it was to merge the sound at a specific point in space. At what frequency does it not matter as much?

Not sure, really depends on the particular speaker... but when Paul sim'd these, he found that tilting or not tilting didn't make much difference.

[cowtown]

Re: Tarkus being "civilized" for acceptance by spouse

Thanks everyone for all the replies. I was honestly expecting a few more "don't do it!" answers, but it looks like it's a go!

This will be a really slow build. I'm learning SketchUp along the way, really want to learn how to build curved cabinets for the first time, and we also have kids in little league, karate, cubscouts, etc. I'll update this thread as I make progress.

Reminds me of my favorite speaker. No reason that couldn't be done, and if necessary, tweaked in the XO.

Pete, your Dayton/Scan design was definitely an influence. They are beautiful.

I really like your proposed design. I can't speak to the crossover specifics, as I don't have the knowledge, but I like your layout of the drivers and the basic overall look of what you propose. What's even cooler is that it shouldn't be all that hard to pull off. Multiple thinner layers for the sides should be easy enough to manage.
I think you have a winner!

Tom, I checked out some of your album last night. Your work is incredible.

Wow, that's a beautiful design.
My quick "thumbnail" calculations say that your proposed baffle width--its average, anyway--is close enough to the original that the crossover should sound the same as the original. Also, Pete is correct that the "tilted" woofer is just for aesthetics, and that the wavelengths are so long at those frequencies (about 3-4 feet around the XO point) that one definitely has some wiggle room in terms of aligning the acoustic centers of the drivers.
I hope your wife gives it the OK, because I sure like it!

Paul, thanks for taking the time to check it out, and for all the work you put in on your designs. I've built three pairs of your Overnight Sensations; 2 pairs for 7.1 surrounds and one for my son's room (the green and gold ones in the picture attached).

Looks good. The top will give you some issues if you want it flat all the way across. If so, you probably want to solve that problem before the cab is assembled.

I was thinking I could probably shim up the cabinets to make a right angle, then run a long flush-trim bit there, but you're right that it will be tricky. I guess a hand-planer could be a fallback position.

Any chance you would share the Sketchup drawing of the stock Tarkus?

Sure thing. I've tried to attach the file. Hope it works. I just started learning SketchUp last week, so no guarantees on whether it's good technique.

btw cowtown, I like the boat-like theme. Make a dbl ender and cut in half and you've got your cabs

I've never done any curves...the Statement Monitors I built about 2 years ago (picture attached) have tapered veneer to try to give that "boat" feel, but it's a spec cabinet build. I like the light/dark contrasts.


Anyway, what's the Peter Principle again? My confidence and ambition will rise just to the point where everything goes horribly wrong? :D


Attachments:
1,2) Statement Monitors with the "boat" theme, Overnight Sensations as decorated by a 6-year old
3) Progress on the curved cabs. A vertical brace with integrated sealed mid/tweet box comes next.
4) Stock Tarkus sketchup model - I put it here: http://www.omsoft.com/cokeefe/tarkus...sREFERENCE.skp

Thanks everyone! I'll keep posting Sketchup pictures at they progress.
Colin

[john trials]

Re: Tarkus being "civilized" for acceptance by spouse

I really like your circular grills. Great idea! I forgot all about those.