Music sub -2 sdx10 or 1 sdx15 ?

[Bfpca]

Hi
I am looking to replace my DIY sub with 2 smaller boxes so I can have more options with placement. The existing sub is 2 Dayton 15" series 2 drivers in a 6cu. ft. box. I am looking to stay under about 3 cu ft on the new ones. I could just transfer the old drivers to new boxes but thought it is a good chance to upgrade to a better driver.
I have been looking at the CSS sdx 15 or 2 sdx10 in a sealed box 3.4 cuft for the 15 and about 2.7 for the 10's. I realize that the 15 on paper will put out more volume with it's 30mm xmax but I am more concerned with sound quality and the 2 10's would play louder as a stereo pair than what I have now. The 10's would be 8 or 2 ohms depending on how they are wired and the 10 is a more ideal load of 4 ohms and would also be about 3db more efficient at 20hz and need less eq.
I am leaning towards these drivers because they are available in Canada and are easier and cheaper to get then ordering from the US. I am looking for input from anyone who has experience with these drivers in sealed boxes for music listening.
I am also considering the GR research or Rythmikaudio servo subs but they will cost me much more and I don't know if the difference will be worth it. Any input on this is appreciated

Thanks
Brian

[planet10]

So you are talking about 4 SDX10 in 2 boxes or 2 SDX15 in 2 boxes?

I'd go with push-push SDX10s. Something similar to what i'm doing with a quad of Bob's Trio8s. I also have a pair of SDX10, but current plans are to use them as woofers in something special.

dave

[Bfpca]

Originally Posted by planet10

So you are talking about 4 SDX10 in 2 boxes or 2 SDX15 in 2 boxes?

I'd go with push-push SDX10s. Something similar to what i'm doing with a quad of Bob's Trio8s. I also have a pair of SDX10, but current plans are to use them as woofers in something special.

dave

Hi Dave

Yes, I am thinking of 2 boxes with 2 10's in each box OR 2 boxes with a 15 in each. I am just trying to get info. on the quality of bass for music that I can expect from these drivers. I will be using a seperate amp and crossover/eq to drive them. If you have heard the 10 or 15 in a sealed box please let me know your impressions. The trio 8 looks like a nice driver. I have been waiting for the sdx12 to make an appearance but there is no news yet. Do you have any idea how high the sdx10 can be used. There don't seem to be any response plots on the css site but the impedance plot looks smooth in the mid bass. I might want to go as high as 150 hz for some experiments I am doing.

Thanks
Brian

[Henkjan]

if you mount the 2 SDX10's on oposite sides of the box (@Dave: is this what you mean with push-push?) then this will give you a very clean sound due to a big reduction in cabinet resonances.

the FR of the SDX10 is rather smooth, no problem using them upto 150Hz.

[head_unit]

Or, you get another set of the Dayton drivers and wire them isobarik, how's that for a left field idea?

If I try top look at specs for your proposed drivers, the site gives a "gateway time out." I presume you can calculate how much air each sub can move based on your Xmax comment. Understand however, that at very low frequencies QUALITY and QUANTITY of sound are quite interrelated. Due to hearing curves, you must generate a loud SPL at low frequencies or you cannot hear/feel it. Look up "Fletcher-Munson" if you're unfamiliar. In other words, you can't really say "I'll give up SPL for better sound quality" UNLESS either set of drivers can put out as much SPL as you need.

At very low frequencies, the 2x10s will load each other and you'll get a 3 dB boost compared to a single 15." But up to what frequency, that's another question you'd need room response software to answer.

If the twin tens don't displace very much less than the 15," go ahead with them. I feel from your post like you're leaning in that direction anyway, and then you have more options for cabinet shape. Don't forget to stuff the boxes very well to gain additional apparent cabinet volume and kill reflection.

[planet10]

Originally Posted by Henkjan

if you mount the 2 SDX10's on oposite sides of the box (@Dave: is this what you mean with push-push?) then this will give you a very clean sound due to a big reduction in cabinet resonances.

the FR of the SDX10 is rather smooth, no problem using them upto 150Hz.

Yes. Push-push typically means opposite sides of the box (althou i have had thot experiments with stuff that ends up much more convoluted)

If i carry my SDX10 project forward, they'll like get used up to about 125 Hz.

dave

[Bfpca]

Hi
The 2 10" drivers are about 1db more efficient than the single 15. However the rolloff is -3 at 44hz versus about 35hz for the 15. This gives the 15 an advantage in sensitivity in the bottom octave. I am now leaning towards going with the 15's for this reason. I am going to build the boxes and install my existing 15's and then upgrade later if I feel the need. The mounting dimensions are close enough to work.
As for brute output capability the sdx15 can on paper move more air (800cm x30mm xmax) then the 2 10's (660cm x 18mm xmax) roughly 6db more output. It would require a lot of power to get that much output.
No matter what output level I am playing them at, the 15 will always have slightly less excursion due to the higher sd. At a level where the 10's are maxed out the 15 would only be at 50% of xmax.
It looks like the sdx15 has quite a clean response and would play up to 150hz ok.

Thanks for the input
Brian

Originally Posted by head_unit

Or, you get another set of the Dayton drivers and wire them isobarik, how's that for a left field idea?

If I try top look at specs for your proposed drivers, the site gives a "gateway time out." I presume you can calculate how much air each sub can move based on your Xmax comment. Understand however, that at very low frequencies QUALITY and QUANTITY of sound are quite interrelated. Due to hearing curves, you must generate a loud SPL at low frequencies or you cannot hear/feel it. Look up "Fletcher-Munson" if you're unfamiliar. In other words, you can't really say "I'll give up SPL for better sound quality" UNLESS either set of drivers can put out as much SPL as you need.

At very low frequencies, the 2x10s will load each other and you'll get a 3 dB boost compared to a single 15." But up to what frequency, that's another question you'd need room response software to answer.

If the twin tens don't displace very much less than the 15," go ahead with them. I feel from your post like you're leaning in that direction anyway, and then you have more options for cabinet shape. Don't forget to stuff the boxes very well to gain additional apparent cabinet volume and kill reflection.

[Brett]

Originally Posted by Henkjan

the FR of the SDX10 is rather smooth, no problem using them upto 150Hz.

Have you actually used them that high? If so, could you post some details of the implementation?

[planet10]

Originally Posted by Bfpca

Hi
The 2 10" drivers are about 1db more efficient than the single 15. However the rolloff is -3 at 44hz versus about 35hz for the 15.

Brian,

Toole has shown that F3 is essentially meaningless in terms of bass extension. Compare F10.

dave

[head_unit]

Originally Posted by planet10

Brian,

Toole has shown that F3 is essentially meaningless in terms of bass extension. Compare F10.

dave

Yeah, F3 ignores the shape/slope of the rolloff, ya gotta look at the whole curve.

For instance, if we limit to sealed boxes using the same driver, a box with a total Q of 0.5 would have a higher F3 compared to a Q of 0.7. But actually the Q=0.5 box would roll off more slowly, and IN-ROOM probably have more extended bass