# Aesthetics Suggestions - Towers



## icor1031 (Mar 24, 2011)

Comment on this design? Does it look good?
34" 12" 12"

The tweeter is not in the middle, it's at the top. It's larger than the mid because I put a 4" waveguide on it.


----------



## Zeitgeist (Apr 4, 2009)

I think that you might have issues with the center. You might want to try building closer to an MTM configuration for the center channel.

Looks like the center-to-center spacing is short between drivers... Normally a good thing.

I'm building a pair of speakers that are something like 9" wide, 10.5" deep and 45" tall. I'm happy with those dimensions. I think that there is a general (cosmetic) preference towards building deeper than wider. Box shapes can sometimes look odd.


----------



## icor1031 (Mar 24, 2011)

Why MTM instead of WMT (what issues?)? If it's for SPL, no worry. 

http://forum.blu-ray.com/showthread.php?t=89614



Zeitgeist said:


> I think that you might have issues with the center. You might want to try building closer to an MTM configuration for the center channel.


----------



## Zeitgeist (Apr 4, 2009)

Interesting read.... reading it now. Thanks!

I'm biased when it comes to centers. My center channel is vertical now - just like the rest of my speakers.

I think that generally the issue with a horizontal WMT is that the dispersion will be very different than vertical. Honestly, I can't think of the last time that I saw a non-MTM (or similar config) horizontal center.


----------



## icor1031 (Mar 24, 2011)

Would you mind explaining this, please? .. or an article?

Thanks!



Zeitgeist said:


> I think that generally the issue with a horizontal WMT is that the dispersion will be very different than vertical.


----------



## Zeitgeist (Apr 4, 2009)

The article that you posted actually mentions part of the problem:
"Remember, if a speaker is operated horizontally, the vertical dispersion becomes the horizontal dispersion and vice versa."

If you move left-right relative to the L/R speakers, you're off-axis horizontally... But if you move L/R relative to the center, you're moving off-axis vertically. 

I'll see if I can find any good links... 

Depending on the dispersion of the drivers -- horizontal/vertical dispersion may not be a big deal. Hard to say without measuring it - or looking at polar plots


----------



## icor1031 (Mar 24, 2011)

I thought it may, it's hard to remember every thing in there. :hissyfit:

.. Dispersion - how does that work? You say vertical, can I just turn the driver 90º? Or, is it related to gravity?

If it matters, they are: 8" Nomex HDS.... 3" Fountek 89.... 3/4" Seas 22TAF/G



Zeitgeist said:


> The article that you posted actually mentions part of the problem:
> "Remember, if a speaker is operated horizontally, the vertical dispersion becomes the horizontal dispersion and vice versa."
> 
> Depending on the dispersion of the drivers -- horizontal/vertical dispersion may not be a big deal. Hard to say without measuring it - or looking at polar plots


----------



## Zeitgeist (Apr 4, 2009)

For cone drivers, dispersion should be more or less the same horizontal/vertically... except for what the baffle might do.

For other stuff...... it can be all over the place for dispersion. Depends on the design.

If anyone else has comments, please feel free. I'm no expert when it comes to dispersion!


----------



## GranteedEV (Aug 8, 2010)

try to mount the mid above/below the tweeter on the center speaker. this will prevent lobing in the horizontal direction from the mid/tweeter crossover. Don't be afraid to make the center speaker sealed if you can get an F3 near 100hz. It'll save some space. Any time you have a crossover without a coaxial speaker (or unity horn), and center to center spacing isn't adequate (it just about NEVER will be except in the bass if you want decent power handling) drivers will have phase cancellations off-axis (or possibly even on-axis if you mess up the crossover). It's a better idea to put those phase cancellations vertical so that our two horizontal ears don't pick them apart.

I would add a large bevel (or roundover) to the left / right speakers to minimize diffraction. check out Jeff Bagby's rubicons for a great example.

Actual dimensions and woofer vertical placement. should be derived from modeling (though CtC is important too, it does hurt less as wavelengths get larger). Towers can have standing wave issues which, if not addressed correctly, can hurt lower mid and upper bass clarity.

The mid should have its own separate chamber from the woofer for best results.

Where did you get the waveguide from? What kind of coverage pattern does it offer?


----------



## icor1031 (Mar 24, 2011)

Plan to make it... Unless you know where I can buy them?






Thanks for the info.



GranteedEV said:


> Where did you get the waveguide from? What kind of coverage pattern does it offer?


----------



## Zeitgeist (Apr 4, 2009)

Rubicon.... I hadn't seen that speaker before...


----------



## GranteedEV (Aug 8, 2010)

icor1031 said:


> Plan to make it...


Designing a good waveguide is pretty dicey stuff.. the math involved is over my head. I dislike beamy / diffractive horns personally. Some parts-express guys have been doing a ton of experiments on waveguide design lately though.



> Unless you know where I can buy them?


Take a gander at the Harman Parts Store for their Infinity Primus P361/362/363 speakers. You'll need a 3/4" tweeter that can play down to around 2.2 khz though, which isn't easy to find.

The easiest way to get a waveguide is to use a coaxial, like the KEF Uni-Q, Tannoy Dual Concentric, and Pioneer CST drivers, as the driver itself IS the waveguide.


----------



## icor1031 (Mar 24, 2011)

Well, I had assumed that 'any waveguide is better than none.'
If there's a lot of math involved, I'll forget about it.

..As to what you mentioned, I'm not sure if the tweeter is good to 2.2k.. It looked more like 2.5k.
What's your thought?
Seas 22TAF/G .. http://www.zaphaudio.com/tweetermishmash/compare.html



GranteedEV said:


> Designing a good waveguide is pretty dicey stuff.. the math involved is over my head. I dislike beamy / diffractive horns personally. Some parts-express guys have been doing a ton of experiments on waveguide design lately though.
> 
> 
> 
> ...


----------



## Zeitgeist (Apr 4, 2009)

GranteedEV said:


> The easiest way to get a waveguide is to use a coaxial, like the KEF Uni-Q, Tannoy Dual Concentric, and Pioneer CST drivers, as the driver itself IS the waveguide.


You left out B&C Coaxials... like the 8CXT :T


----------



## GranteedEV (Aug 8, 2010)

Horns in general, but especially waveguides intended for low throat and mouth diffraction and controlled directivity, have a _ton_ of math involved. Even the sim programs are confusing IMO. 

A system with a good waveguide is preferable, but waveguides themselves are not common so for DIY, you're stuck with the hand you're dealt.


----------



## GranteedEV (Aug 8, 2010)

Zeitgeist said:


> You left out B&C Coaxials... like the 8CXT :T


Prosound coaxials huh. I just dunno about them. Really dynamic but I'd have trouble convincing myself to buy one, although i've come rather close with the Radian 8s.


----------



## icor1031 (Mar 24, 2011)

Well, you saved me $300 on a wood lathe...
Sad to hear that, but at least I'm not wasting my time. 

Thanks!



GranteedEV said:


> Horns in general, but especially waveguides intended for low throat and mouth diffraction and controlled directivity, have a _ton_ of math involved. Even the sim programs are confusing IMO.
> 
> A system with a good waveguide is preferable, but waveguides themselves are not common so for DIY, you're stuck with the hand you're dealt.


----------



## GranteedEV (Aug 8, 2010)

icor1031 said:


> Well, you saved me $300 on a wood lathe...
> Sad to hear that, but at least I'm not wasting my time.
> 
> Thanks!


Don't get me wrong, people have gotten results they subjectively liked from just routing out a big cone, but that's a trial and error approach, not really a scientific one. 

Search around for augerpro's waveguide for the tangband 75-1558 to get any idea of how unpredictable things can get.


----------



## Zeitgeist (Apr 4, 2009)

GranteedEV said:


> Prosound coaxials huh. I just dunno about them. Really dynamic but I'd have trouble convincing myself to buy one, although i've come rather close with the Radian 8s.


Not cheap.......... Really well built and sound great though. I like the B&C, don't know much about other pro coaxes..


----------



## erwinbel (Mar 23, 2010)

A DIY center with the correct vertical mid/tweeter arangement:
http://www.troelsgravesen.dk/8008CENTER.htm

A DIY standmount (although it's 40 liters...) with waveguide:
http://www.troelsgravesen.dk/QUATTRO.htm

You can buy the plastic waveguide and all the other parts at Jantzen (Denmark). See link in Troels webpages.

My favourite, also with waveguide, which I will be building as my LR in my 11.2 set:
http://www.troelsgravesen.dk/DTQWT-12.htm

I would use the Quattro's for back surround and for Height (hanging upside down from the ceiling)


----------

