Must Center Channels Always Have Two Woofers?

[jeffsg4mac]

You know at this point I wonder how a Bi-Pole would be as a center?

 

[WmAx]

Correct me if I am wrong, but the first part of the article seems to be referring specifically to MTM designs placed horizontally, not TM designs.

I suggest you ignore the article at the online magazine. It is of very limited accuracy, and does not seem to explain matters very well. I did not read the article fully, but just from the first parts, it is apparent that the understanding of said author is not sufficient to describe(or realize the sum effect) the physical behaviour(s).

I would refer you to the following article for a very thorough explanation of a MTM system behaviour:

Vertically Symmetric Two-Way Loudspeaker Arrays Reconsidered
Preprint Number: 4186, Convention: 100 (April 1996)
Konar, M.

You can find a version of this article at Konar's website:

http://www.birotechnology.com/articles/VSTWLA.html

-Chris

 

[WmAx]

Chris,

Thanks! So if I were to align the tweeter and the woofer horizontally (TM), there should be no real negative effect, or did I misunderstand that?

This is dependant on the specific crossover frequency, diameter of drivers and crossover topology that is used. However, regardless of this, the overall lobing around the crossover frequency in the horiztonal plane will be worse with the TM system of comparable specifications when compared to the MTM system, if both are layed horizontally. Though the actual overall net effect(not just around crossover) depends too heavily on the factors I just mentioned in the first part of this paragraph to say one way or another without an individual analysis of a specific TM. This is no issue when using the TM vertically oriented. If you use a TM vertically, then it is superior in all important parameters compared to a similar MTM layed horizontally.

It should not matter what side of the woofer the tweeter would be on then either, correct? If neccessary I can align them verically (TM) I guess.

You can try it layed horiztonally in order to see if this is acceptable sound quality, but I highly recommend using a TM speaker in a vertical position for the highest quality sound. The horiztonal dispersion will be optimal in vertical position.

-Chris

 

[jeffsg4mac]

" This is no issue when using the TM vertically oriented. If you use a TM vertically, then it is superior in all important parameters compared to a similar MTM layed horizontally."

That is what I wanted to hear, just confirms what I have experienced.

 

[Tomorrow]

This is dependant on the specific crossover frequency, diameter of drivers and crossover topology that is used. However, regardless of this the overall lobing around the crossover frequency will be worse with the TM system of comparable specifications. This is no issue when using the TM vertically oriented. If you use a TM vertically, then it is superior in all important parameters compared to a similar MTM layed horizontally.



You can try it layed horiztonally in order to see if this is acceptable sound quality, but I highly recommend using a TM speaker in a vertical position for the highest quality sound. The horiztonal dispersion will be optimal in vertical position.

-Chris

Chris, how would the typical 3-way CC fit into your evaluation?

 

[WmAx]

Chris, how would the typical 3-way CC fit into your evaluation?

Please be more specific.

-Chris

 

[annunaki]

This is dependant on the specific crossover frequency, diameter of drivers and crossover topology that is used. However, regardless of this, the overall lobing around the crossover frequency in the horiztonal plane will be worse with the TM system of comparable specifications when compared to the MTM system, if both are layed horizontally. Though the actual overall net effect(not just around crossover) depends too heavily on the factors I just mentioned in the first part of this paragraph to say one way or another without an individual analysis of a specific TM. This is no issue when using the TM vertically oriented. If you use a TM vertically, then it is superior in all important parameters compared to a similar MTM layed horizontally.



You can try it layed horiztonally in order to see if this is acceptable sound quality, but I highly recommend using a TM speaker in a vertical position for the highest quality sound. The horiztonal dispersion will be optimal in vertical position.

-Chris

Chris,

That is more or less what I expected. Thanks for the information. Greatly appreciated.

 

[Tomorrow]

Please be more specific.

-Chris

Will there be lobing effects (or differentials) around the crossover frequencies of a typical CC 3-way design in vertical vs. horizontal presentation?

Pardon my technical lack of experience, but I'm trying to understand this. (Perhaps a clearer definition of lobing is necessary for me?)

Thanks for your patience.

 

[majorloser]

When you get right down to it, most center channels have been designed to be used in the horizontal position. For the most part they have been designed to be used above or below a television.

That being said, a speaker with two smaller woofers is shorter than a cabinet with one large woofer.

So much for the idea of all speakers of equal design and size

 

[WmAx]

Will there be lobing effects (or differentials) around the crossover frequencies of a typical CC 3-way design in vertical vs. horizontal presentation?

Pardon my technical lack of experience, but I'm trying to understand this. (Perhaps a clearer definition of lobing is necessary for me?)

Thanks for your patience.

I am sorry, I should have been more clear. I meant for you provide a specific example of a 3 way CC so that I can get know which crossover ranges, driver distances and dimensions. I'm afriad I don't know what constitutes a 'typical' 3 way CC design. Most are 2 way, and usually have very common characteristics that can usually be generalized.

-Chris

 

[Sheep]

I always though they were MTM because they needed a wider soundfield.

Tare me down if its wrong WmAx.

SheepStar

 

[WmAx]

I always though they were MTM because they needed a wider soundfield.

Tare me down if its wrong WmAx.

SheepStar

If you would read my replies to the original thread starter, all would probably be clear.

-Chris

 

[Sheep]

If you would read my replies to the original thread starter, all would probably be clear.

-Chris

Well, I just read that. Hm, now I'm looking for a new center.... One C-1 on its side

SheepStar

 

[Tomorrow]

I am sorry, I should have been more clear. I meant for you provide a specific example of a 3 way CC so that I can get know which crossover ranges, driver distances and dimensions. I'm afriad I don't know what constitutes a 'typical' 3 way CC design. Most are 2 way, and usually have very common characteristics that can usually be generalized.

-Chris

Here is a link to what I'd consider a 'typical' 3-way CC.
http://www.jbl.com/home/products/product_detail.aspx?prod=EC35&CheckProduct=Y
I've seen many similar from varying manufacturers. But I'm also interested in the performance perameters of such an application (vertical vs. horizontal) of 3 way floor-standing speakers (3 identical speakers, l/c/f)...measurements and identities unknown at this time. So are there general statements that you can make about this kind of application...usually TMW?

Thank you.

 

[Sheep]

what about a center channel with a tapered crossover?

http://www.energy-speakers.com/v2/products/product-page.php?id=15

One midrange driver cuts out lower then the other?

SheepStar

 

[WmAx]

Here is a link to what I'd consider a 'typical' 3-way CC.
http://www.jbl.com/home/products/product_detail.aspx?prod=EC35&CheckProduct=Y
I've seen many similar from varying manufacturers. But I'm also interested in the performance perameters of such an application (vertical vs. horizontal) of 3 way floor-standing speakers (3 identical speakers, l/c/f)...measurements and identities unknown at this time. So are there general statements that you can make about this kind of application...usually TMW?

Thank you.

In reference the JBL product that you linked: given the overall dimensions/spacing and crossover frequencies, this product will behave much like a TM, not like a typical MTM. The bandwidth of the LF drivers is limited to 800hz crossover point, and with 5" drivers spaced at this distance, is not a significantspacing in relation to the wave lengths in air. Some interference will occur at the top band of the woofers after the crossover point, but it would be minimal. The very small diameter of the midrange will allow excellent dispersion . While I do not know the specific details of this particular device, nor have I seen it's specific measurements, the operational premise has excellent potential.

-Chris

 

[WmAx]

what about a center channel with a tapered crossover?

http://www.energy-speakers.com/v2/products/product-page.php?id=15

One midrange driver cuts out lower then the other?

SheepStar

The tapered crossover(at the frequency and spacing used) would prevent any destructive interference from occuring off axis between the woofers. This speaker will behave like a TM layed horizontally.

-Chris

 

[Tomorrow]

In reference the JBL product that you linked: given the overall dimensions/spacing and crossover frequencies, this product will behave much like a TM, not like a typical MTM. The bandwidth of the LF drivers is limited to 800hz crossover point, and with 5" drivers spaced at this distance, is not a significantspacing in relation to the wave lengths in air. Some interference will occur at the top band of the woofers after the crossover point, but it would be minimal. The very small diameter of the midrange will allow excellent dispersion . While I do not know the specific details of this particular device, nor have I seen it's specific measurements, the operational premise has excellent potential.

-Chris

Thanks, Chris! That is very helpful. (On the other speakers, I of course meant L-C-R, not the typo'd l/c/f.)

 

[mulester7]

Thanks, Chris! That is very helpful. (On the other speakers, I of course meant L-C-R, not the typo'd l/c/f.)

.....and just think, RJBudz, six months ago, WmAx was torn between being a brain surgeon and a soda-jerk just like Jethro Bodiene....he'll frown over this attempt at humor, RJ, but that's just because he's that far above us on what will, and will not, tweak out in these sound-systems.....Chris goes for the pure right off the bat in the plannings....WilliamAxe, rave on, Sir, on our level, with your ego checked at the door, as should we all if we're most interested in learning.......


.....edit....boys, Ellie Mae Clampett done more for bluejeans in one thirty minute episode, than cowboys done in 200 years, immho.....

 

[Sheep]

The tapered crossover(at the frequency and spacing used) would prevent any destructive interference from occuring off axis between the woofers. This speaker will behave like a TM layed horizontally.

-Chris

Yay, go energy!

SheepStar