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Discussion Starter #1 (Edited)
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.
 

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Discussion Starter #3
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.
 

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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.

sdx15.JPG
 

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Discussion Starter #5
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.

View 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?
 

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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.
 

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Discussion Starter #7
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??
 

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Discussion Starter #9
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.
 

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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".
 

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You need to 'borrow' a sub and see how much output you need. I never imagined that I would need the size I now have, but the low end content in these movies demand a lot of excursion/displacement, room dependent as others mentioned. The shiva gen 1 looks really good as cost/benefit and gets you in the door quite frugally...however, having extra headroom is very nice, at a cost. Again, really really try to test your room with a sub at your desired listening level so you can get an idea.
 

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Discussion Starter #12
Hi,

I have finally asked my friend to place an order for the css sdx-15:bigsmile:

Now the amp, this is getting to be troublesome. I want either a 500 or 1000w amp. it has to support 220v also. I also need a HPF (must as its going to be a ported design) at around 18-20hz range in the amp, and preferrably a low pass crossover also (not essential though as i will be using an avr). the boost around the cutoff frequency preferrably should not be there, probably 1-2 db max if it cant be helped. I would prefer a bash or class d amp as the power wastage is less (save the environment as well as my power bill). PEQ would be good too.

Not many options with these features.. the oaudio has 3 db boost at whatever hpf freq you use. All the PE ones are listed at 110 volts. keiga is too expensive, eD doesnt have subsonic filter as per their site... so what are my other options. dont want ep2500 kind of pro-amp. too many headaches - seperate hpf and eq, fan changing, low waf, heat generation, adaptors for balanaced i/o etc.....

thanx
 

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The O-Audio amp has an estimated 8 db of boost at 12 hz, 6 db of boost at 16 hz, 4 db of boost at 20 hz and no boost at 25 hz. The 4 db of boost at 20 hz can be eliminated since the EQ has an effective range of 18 - 80 hz.

The Dayton 1000 watt amp would be ideal with its third order HPF at 18 hz and its EQ ability. Have you considered using a voltage converter?
 

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Discussion Starter #14
The O-Audio amp has an estimated 8 db of boost at 12 hz, 6 db of boost at 16 hz, 4 db of boost at 20 hz and no boost at 25 hz. The 4 db of boost at 20 hz can be eliminated since the EQ has an effective range od 18 - 80 hz.

The Dayton 1000 watt amp would be ideal with its third order HPF at 18 hz and its EQ ability. Have you considered using a voltage converter?
is there a way i can simulate this behaviour in winisd. I would aim to tune the box at about 18hz, so the filter will be at 16hz. If I use the eq to fix the 20hz boost, then I cant use the eq at any other range as I think it operates only in one range. that would become an issue with fixing room response. cant the avr (yamaha rx-v663) help with the ypao system to equalize these things? I am not sure as i have never used a sub before.

no, the voltage converter has a low waf as its big ugly box, I am already using one for the avr. another one and i am a dead man....
 

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Discussion Starter #16
With the HPF set at 16 hz the 6 db of boost is at 16 hz, not 20 hz. The boost can't be cut due to the EQ's lower limit of 18 hz.
got it.

Just got an email from parts express about dayton hpa amps and 220v. this is what they have to say:

"Yes these amps do work on 220 V. All you would need to do is take the fuse out and flip it. The high pass filter is at 19 Hz. There are no bass boosts built into this amp, but they both do have EQ on board so you can boost or cut a range of bass frequencies."

Does this sound reasonable, flipping a fuse to change voltage.
 

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I've never heard of "flipping a fuse to change voltage".
even i have never heard of it, thats why I am skeptical. If I order it and the flipping doesnt work, and I plug it in, boom it will go. Is there a way to test it for input voltage requirement without plugging it in.

my friend called up support and talked to someone different. This person said the same thing.

" When you receive the amp, pull out the fuse hlder and flip it 180 degrees and put it back in. This will allow a 220v input."
 
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