I have been thinking about the center speaker to compliment my mains. I just want the opinion of the group on this concept.
The front mains are crossed over at 6500Hz (series). If I cross the center the same as the mains (ideal) then should I be concerned about comb effects from the two W4's? I tried to get the drivers as close as posible and the dimentions match that of the mains on its side and slightly longer. (7.5"Hx13.5"Wx7"D for 6.5L)
Here is a pic of the concept done in Photoshop....
The front mains are crossed over at 6500Hz (series). If I cross the center the same as the mains (ideal) then should I be concerned about comb effects from the two W4's? I tried to get the drivers as close as posible and the dimentions match that of the mains on its side and slightly longer. (7.5"Hx13.5"Wx7"D for 6.5L)
Here is a pic of the concept done in Photoshop....
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as Navin said 3000 HZ is ideal....speeech frequency is centred at around 3500 Hz and I take it thats why you want a centre speaker set up is for vocals ie: centre stage
cross it over at 3k
No lower.
The 28-847 or 847S has a fast drop off after 3K nevr mind the posted 600 FS.
Just my 2 cents
No lower.
The 28-847 or 847S has a fast drop off after 3K nevr mind the posted 600 FS.
Just my 2 cents
3k?
Hmm....
Why would I want to crossover at 3k when that is exactly where I dont want a crossover? If the vocal range is centered around that area, why not put the crossover point much higher. This was the idea for the mains. I chose the W4-656S so I could cross much higer. I was under the impression that you didn't want a crossover in the critical vocal range if you could help it. Most 6" drivers break up after 3k so you cross over at or near that, correct? If I'm totaly off base here please set me straight.
And if so would you sugest crossing over the mains at 3k as well?
They sound freakin great right now. Much to my suprize I might add. The crossover is as simple as it gets with no Zoble on the woofer and no pad on the tweet. Keep in mind this was my first serious atempt at HiFi speakers.
Al, what in your opinion is the best crossover point for the two drivers I'm using? I ask because you seem to be the authority on Tangband drivers. You've already been a great help. Thanks in advanced.
And.... just a thought.... but...
Most center content is lopped off at around 7k anyway right? So, do I even need the tweeter if the 656's go up to about 18k?
Chris
Hmm....
Why would I want to crossover at 3k when that is exactly where I dont want a crossover? If the vocal range is centered around that area, why not put the crossover point much higher. This was the idea for the mains. I chose the W4-656S so I could cross much higer. I was under the impression that you didn't want a crossover in the critical vocal range if you could help it. Most 6" drivers break up after 3k so you cross over at or near that, correct? If I'm totaly off base here please set me straight.
And if so would you sugest crossing over the mains at 3k as well?
They sound freakin great right now. Much to my suprize I might add. The crossover is as simple as it gets with no Zoble on the woofer and no pad on the tweet. Keep in mind this was my first serious atempt at HiFi speakers.
Al, what in your opinion is the best crossover point for the two drivers I'm using? I ask because you seem to be the authority on Tangband drivers. You've already been a great help. Thanks in advanced.
And.... just a thought.... but...
Most center content is lopped off at around 7k anyway right? So, do I even need the tweeter if the 656's go up to about 18k?
Chris
Vocal fundamentals are nowhere near 3K. MUCH lower.
Six inchers vary quite a bit on breakup characteristics; I haven't used the Tangbands, so can't comment. But they're all six inches, which means that they're starting to get beamy by 3K. To avoid discontinuities in the polar pattern (the "dip and horns" seen in a waterfall display of FR curves versus horizontal angle), you need to cross over at 3K or lower and make that crossover pretty steep- 4th order will work well.
Six inchers vary quite a bit on breakup characteristics; I haven't used the Tangbands, so can't comment. But they're all six inches, which means that they're starting to get beamy by 3K. To avoid discontinuities in the polar pattern (the "dip and horns" seen in a waterfall display of FR curves versus horizontal angle), you need to cross over at 3K or lower and make that crossover pretty steep- 4th order will work well.
The W4s are, I do believe 4 inchers, which are in effect almost fullrange drivers (the ones I've tried, not sure which model swirvis using).
A high crossover point is good for the mains, but I'm not too sure about your center channel, for you are using two W4s, and if they produce the higher frequencies then lobing could occur.
I'm guessing that's the reasoning behind the lower crossover point. But the W4s I've used sounded much better with high crossover points.
A high crossover point is good for the mains, but I'm not too sure about your center channel, for you are using two W4s, and if they produce the higher frequencies then lobing could occur.
I'm guessing that's the reasoning behind the lower crossover point. But the W4s I've used sounded much better with high crossover points.
Im using the W4-656S 4" Full range driver 65-18kHz. The reason I mention 6" drivers was refrence to the 3k crossover point. You cross 8's at 1k 6's at 3k in general. I crossed the 656's at 6.5k and they sound great.
JoeBob hit on what concerned me most. Lobing. Is it going to be that big an issue? Should I omit one of the W4's? (would make for an unatractive center) I know sound is more important than looks but...WAF?
At what freq am I going to start getting into trouble? These are just 4" speakers and they will be an inch apart.
And if I cross the center at 3k will itl not match the mains sonicly?
Thanks again for the info.
Chris
JoeBob hit on what concerned me most. Lobing. Is it going to be that big an issue? Should I omit one of the W4's? (would make for an unatractive center) I know sound is more important than looks but...WAF?
At what freq am I going to start getting into trouble? These are just 4" speakers and they will be an inch apart.
And if I cross the center at 3k will itl not match the mains sonicly?
Thanks again for the info.
Chris
What order are you crossing these over at? If you're using a first order, the use of such a wideband driver is great for your mains, a high and low order crossover gives a great sound.
But for the center, if you've got a low order, then you can get nasties from the multiple drivers even if the xover point isn't excessively high.
What I would do if I were you would be to crossover at a higher frequency (if you've already worked out an xover that you like at 6.5k, use it again), but only do that on one driver. With the 2nd driver, use it to make a 2.5 way, have the 2nd W4 fill in the bass by having it's crossover frequency much lower than the other (obviously, don't just guess, measure and test until it sounds right).
But for the center, if you've got a low order, then you can get nasties from the multiple drivers even if the xover point isn't excessively high.
What I would do if I were you would be to crossover at a higher frequency (if you've already worked out an xover that you like at 6.5k, use it again), but only do that on one driver. With the 2nd driver, use it to make a 2.5 way, have the 2nd W4 fill in the bass by having it's crossover frequency much lower than the other (obviously, don't just guess, measure and test until it sounds right).
I agree wtih joe bob lobing is the question here. to know when lobing is going to set in yo gotta see the cetner to center distance between the 2 W4 and hopefully that wold less than the wavelength of the highest freq you want to produce.
i would not worry too much about beaming for a center channel in some ways it helps keep the dialogue centered 🙂
so your drivers c-c is about 5" i think in metric so that is 127mm or 0.127m. speed of sound is about 340m/s so 340/.127 = 2677 which is how i came up with 3k. sorry fornot being so clear to begin with.
as far as lobing in a center channel i find that above 10k it really cant be heard. for example i put 2 tweeters close together so that the c-c is about 2" (5cm) and lobing should occur at about 7k. but i can hear it as of now.
i would not worry too much about beaming for a center channel in some ways it helps keep the dialogue centered 🙂
so your drivers c-c is about 5" i think in metric so that is 127mm or 0.127m. speed of sound is about 340m/s so 340/.127 = 2677 which is how i came up with 3k. sorry fornot being so clear to begin with.
as far as lobing in a center channel i find that above 10k it really cant be heard. for example i put 2 tweeters close together so that the c-c is about 2" (5cm) and lobing should occur at about 7k. but i can hear it as of now.
An externally hosted image should be here but it was not working when we last tested it.
Well you can see what I have the W4-657S and 25-302S crossed at here.
Using the 28-847S in the tweeter will be best crossed over at the same as these.
Lobiling and so one are a concerner yes
But in a MTM using the 4" drivers pull them as close as you can and use the 25-302s or the 28-847S and cross them out at 3k
Position the tweeter the low end of the design not the upper.
If you have this on a shelf or TV.
This helps with the dispersion.
All of the 4" drivers at 20 dgrees off axis fall off at 9-10 fast.
But that is just my 2 cents.
If you want to keep xover simialr to your mains ie higher than 3k, then I would add another 4" as a mid only.
So you now have 3 drivers along the bottom of the enclosure, the mid directly under the tweeter & the 2 outer x-ed over much lower, say 200hz.
That way you will not have any lobing issues, plus you wil lhave better bass response & efficiency.
Keep in mind when you add the centre speaker to your ht setup it will reproduce about 70% of the sound, with just some going to your mains/rears.
So you now have 3 drivers along the bottom of the enclosure, the mid directly under the tweeter & the 2 outer x-ed over much lower, say 200hz.
That way you will not have any lobing issues, plus you wil lhave better bass response & efficiency.
Keep in mind when you add the centre speaker to your ht setup it will reproduce about 70% of the sound, with just some going to your mains/rears.
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