Seas 3-way - this or that?

[Norcad]

Hello
Im planning on a 3-way, all Seas front-speaker.
And this is what I'm thinking so far:
* Wide baffle, 50-55cm.
* Active bass, xo about 250Hz because of bafflestep.
* CA26RFX or L26RFX/P in bassreflex.
* One or two CA18RNX as mid
* 27TFFC or 27TDFC as tweeter.
* Passive xo mid/tweet at 2000-2500Hz.
I'm planning for a full 5.1-system here, thats why the CA18 and not a smaller unit are used as mid. The other 3 speakers will be two way, with CA18 as mid/bass.

I had big hopes for the L26, and purchased them first. But in a closed boxed (20L & 50L tried) they just meet x-max to easy.
In 50L bassreflex this is better, still the enclosure are a little to small for the driver.
WAF demand a nicer looking driver, more like the paper-mid.
So I've bought the CA26 also. They are now playing in 50L bassreflex, looks! and sound good, but the L26 played deeper.
On the other hand, CA26 has better sensivity.

If I use the CA26, maybe I should use two CA18? It looks perfect in Bassbox.................

This just makes a new qt (if I use 2xCA18), should I go for TMMW or MTMW?

And in the end (where my brain is frying) the qt about waveguide are popping up also...........

Please help me out!

[tinitus]

Just a single mid should be fine, and I would use a 5" like the MCA15RCY, or maybe even better the MCA12RC

[tinitus]

Ahh, I see, you want no small midrange

If you go fore double 6" it might be better to use one of them as a 0.5way, and going active you could cross the woofer lower and still have BSC, but might be more tricky

But you have a sub ... have you thought about using triple 6" in a 2.5way... that way you could have the same driver and xo in the whole setup

using the same driver doesnt result in the same sound with different xo, one being 3way and others being 2way - different design=different sound

Just thoughts!

[sreten]

hi, http://www.troelsgravesen.dk/PMS.htm , /sreten.

[Norcad]

Well I agree that a smaller mid would be better, but even if its difficult to get the same sound from the same drivers with different xo and different cabinets. I think it would be very, VERY hard to get it with different drivers. And smaller drivers than 7" in the center and surround speakers are not an issue!

When I simulate 2xCA18 and the CA26 in Bassbox pro, they are very simular in the 50-500 Hz range. And for the passive xo, the biggest problem is the centerspeaker, because of its horisontal baffle. But that problem would be the same, even if I used 2 or 3 CA18 in the front speakers.

I know that one CA 18 works fine, but will two be even better?
Both CA26 and 27TFFC has a 91/92dB sens. CA18 has 88dB......?

[tinitus]

In your first post you write..."active bass, xo about 250hz because of bafflestep"

I thought you knew about BSC, but obviously dont

With a 92db woofer and 88db mid you get perfect BSC.. actually the 88db mid might be slightly more than 88db when used as a mid only ... and the woofer may not be 92db at all ... so maybe not enough BSC after all, and in the end you actually may have to attenuate the mid

A lot of people have many theories how to get good sound and what is important, and I believe that its true that all the speakers in a surround setup should have the same nature ... but it dont really mean nothing if you dont have the skills to execute it

[Jay_WJ]

Have you looked at nonlinear distortion data for the CA18RNX? Look at here: http://www.zaphaudio.com/6.5test/compare.html

Compare the CA18RNX and the new ER18RNX. Distortions of all types, espeically odd order ones, are significantly lower for the ER18RNX than for the CA18RNX in the 200 to 1000 Hz range. The new ER's cone is basically paper and wouldn't look bad with CA26RFX.

I think the driver choice of 27TDFC, ER18RNX, and CA26RFX is excellent. No doubt they will be great speakers if XO's are well designed.

L26 will give a bit cleaner bass, I guess, but CA26 will give a better look with other drivers.

I don't think you'll need two midrange drivers. You'll lose the woofer's sensitivity due to baffle step, anyway.

-Jay

P.S. I'd use 1.5 - 1.6 kHz as a mid/tweet xo point. The TDFC can handle this. It will give better system harmonic distortions.

[Norcad]

Yes I know what baffle step is, and yes I wrote active bass.
If I used passive xo all the way I agree with you.
But with active xo and amps, I can use gain to adjust the the BSC (I hope).
I want the extra SPL, without the extra distortion, thats why I wondering about 2 mids.
If I have the skills? No I dont, (thats why I'm asking!) but I'm planning to get there......

I bought the CA18 before ER18 was launched, if not I would have bought the ER18 instead.

(Puh its hard to write english, hopefully someone understand what I mean........ )

[Jay_WJ]

I see you already have the drivers. If you cross the mid at 200 to 300 Hz with the woofer, I don't think a single CA18 will have any difficulty playing loud without distortion. The woofer will give up ahead of the mid as SPL increases.

BTW, you will do the crossover work yourself?

[sreten]

Originally posted by Norcad
Yes I know what baffle step is, and yes I wrote active bass.
If I used passive xo all the way I agree with you.
But with active xo and amps, I can use gain to adjust the the BSC (I hope).
I want the extra SPL, without the extra distortion, thats why I wondering about 2 mids.
If I have the skills? No I dont, (thats why I'm asking!) but I'm planning to get there......

I bought the CA18 before ER18 was launched, if not I would have bought the ER18 instead.

(Puh its hard to write english, hopefully someone understand what I mean........ )

Hi,

BSC affects max SPL just as much as it effects frequency response.
Increasing bass gain will not increase maximum SPL. The distortion
and levels to worry about are generally in the bass, not midrange.

/sreten.