CSS SDX15, HPSA500 build, need help in design.

[doors]

Hi Guys,

I am planning to make a sub. It will be my first attempt at DIY, and it will be my first sub. I wont be doing much, just buy the driver and the plate amp and get the cabinet made by a carpenter.

Size – Max size allowed (read WAF) including everything.
24” cube maximum.

My budget is around 700-750$ including shipping in US, but I prefer to do this in around 600$.
I am thinking about a 500W OAUDIO bash amp or ED LT.500 along with a 15” or 18” driver.

I am looking for a 15” or 18” driver. So far from research, I like the AE AV15 (both x and h) and the CSS SDX15. I also thought about the maelstrom, but it needs atleast 1000w power and I cant go for both maelstrom and a 1000w amp. If I get a 1000w amp (around 450$), then the driver has to be below 300$, or I can spend 250 on amp and about 400-500 on driver.

Is a single shiva going to be enough for this much area.
How good is the ED 19Ov.2
Any other good options I should consider.

The sub should be musical, but should also have good SPL for movies. Dual subs are ruled out, though I can have 2 drivers (e.g. shiva 12”) in the same sub, separate amp is ruled out, I have to go for a plate amp, as wife is not ok with another component.

I would prefer a downfiring (due to small kids) sealed sub as those are more musical, and easy to make, but still would want good enough SPL for movies. If it cant be done with sealed, well then I guess it will be ported or PRed.

Listening area

I live in an apartment, the flooring is marble and walls are brick and concrete.
The main listening area is 19.5 x 18.5 x 10.5
3787 cubic feet. The system is kept along the 18.5 ft wall. The listening positions is about 12 ft.

But the Dining and open kitchen is open and attached to it, and the total area is 31.5 ft x 18.5 x 10.5 = 6118 cubic feet
Let me know if a rough diagram of the room will help in suggesting a sub and I will post it.

Usage
50% music and 50% movies
I mainly listen to classic rock, blues, heavy metal, jazz, classical music etc. Watch all sorts of movies from classics to action, scifi etc.
I am not a bass freak, did I mention its my first sub and dont listen at ear bleeding levels, except maybe once in a while.

Current setup
Yamaha RX-V663, B&W 602 S2 – goes to about 52 hz.

I don’t know much about DIY, so I will be needing a lot of help from you guys.

Thanx in advance.

[Mike P.]

Here's a SDX15 kit that's designed for a 24 inch cube and fits your budget at $750 shipped.

http://creativesound.ca/details.php?model=QUARTET15

[doors]

Mike P. wrote:

Here's a SDX15 kit that's designed for a 24 inch cube and fits your budget at $750 shipped.

thanx for the reply. This is a good option and a good deal, but I would prefer to avoid a PR if possible, due to small kids at home, more things for them to poke at.

[Mike P.]

Understood. The SDX15 in a 24 inch ported cube would work well with a 1000 watt plate amp and 2 4" flared ports 26 inches long each. It would require the use of elbows to turn the ports to make them fit, or you could use a slot port which would be simple enough for the cabinet maker to build into the cabinet. With room gain this setup would be capable of 116+ db at 20 hz.

[doors]

Mike P. wrote:

Understood. The SDX15 in a 24 inch ported cube would work well with a 1000 watt plate amp and 2 4" flared ports 26 inches long each. It would require the use of elbows to turn the ports to make them fit, or you could use a slot port which would be simple enough for the cabinet maker to build into the cabinet. With room gain this setup would be capable of 116+ db at 20 hz.

Attachment 15502

Thanx. I like the slot port idea, better than a complicated 26" port. Will definitely consider it. Any good sealed options? Would a sealed be good enough for my living room.
Any good 18" options that will fit in my budget?
I am trying to plot some of the drivers in winISD. There does not seem to be any calcualations for the room. How do I know how much room gain/loss will be there. How much db should be enough in my room?

[Mike P.]

18's need more room to gain any SPL or low end extension advantage. The Maelstrom-X and IXL-18 both model the same as the SDX15 in the given box size and amplifier power. A rule of thumb is it takes 2 sealed subs to produce the same output as one ported sub.
Room gain in an average size room is usually around 6 db at 20 hz.

[doors]

Mike P. wrote:

18's need more room to gain any SPL or low end extension advantage. The Maelstrom-X and IXL-18 both model the same as the SDX15 in the given box size and amplifier power. A rule of thumb is it takes 2 sealed subs to produce the same output as one ported sub.
Room gain in an average size room is usually around 6 db at 20 hz.

how much room gain will be there in a very large room. I guess it should be less than 6db right, more like 3 db??

[Mike P.]

That's hard to say, every room has a different effect due to size, shape, construction materials, sub placement, etc.

[doors]

Hi,

I tried the plot for the sdx-15 in a 6 cuft box with 1000 watts, tuned to 20hz and a 20hz highpass filter. The port velocity goes to about 23 m/s. I read in the forums that the port velocity should not exceed 17 m/s. I also read that with 2 4" ports or one 6" port, there is no need to worry about port velocity. Which of these is true. How much high can I go with a dual 4" port or single 6" port in terms of air velocity. This is the problem I am facing with the designs, either the port velocity shoots up or the port length becomes unmanageable. Any guidelines for these?

I also did a plot of shiva 12", with a 500w amp in a 6.5 cuft box, tuned to about 18-20hz with highpass filter, I see a very similar graph to css sdx-15 with 1000w amp, just a couple of db less for shiva. Is there a sense in going with the css, when a shiva can give me almost similar performance? The shiva setup is going to cost me almost half of the css setup.

Thanx.

[Mike P.]

Keeping the air speed under 26 m/s is usually recommended for HT subs as that is where port compression starts. With flared ports port noise isn't a issue at that speed.

There's more the just a couple of db difference comparing a 500 watt Shiva-X to a 1000 watt SDX15. The SDX15 would have a 3 to 4 db advantage in the 16hz to 25 hz range and a 5+ db advantage from 25 hz on up. It's all about how much money you're willing to spend and the best performance you can get for your budget and stated box size of "24” cube maximum".