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Looking for Home Theater Subwoofer idea

post #1 of 24
4/24/12 at 2:22pm
Thread Starter 
Hello all. I am Working on a theater in my basement and am looking for some advice on a DIY subwoofer for my system. I posted in another forum and got alot of good ideas for other speakers but not alot of good ideas for a sub. I noticed in this forum that there is a special thread for DIY subs. Looking at the list of DIY's, I couldn't quite come to a conclusion.

For my mains and center, I am going to build 3 Stentorians. For my rear and rear surrounds, I am going to build 4 Sten II's. I have a Denon AVR-1912 receiver. I have an Epson 3010 projector that I will use in the room as well.

Now, for the sub, I don't want anything crazy but I would like something decent. As I posted in the other forum, I have a limited budget so I need to keep the cost as low as possible. I would like to keep it to one sub now. I may build another later when I have more money to spend. My room size is about 13' by 20'. I would plan on putting it in the front left or right corner of the room.

So, my question is, can you recommend one of the builds listed on the DIY sub page that would fit my needs? Any help would be appreciated.

Thanks.
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post #2 of 24
4/24/12 at 2:30pm
Without giving a budget, no. How much can you spend, now, for driver, amp, EQ and materials such as MDF? How big is your room?
Where are you?
Quote:


I don't want anything crazy

Are you sure you're asking in the right forum then?
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post #3 of 24
4/24/12 at 2:53pm
http://stories.parts-express.com/sto...7/redirect.htm

You can use the woofer specified or replace it with the cleaner sounding and higher power handling RSS315HO-4. Use a plate amp up to 500 watts, depending on what your budget allows. You can also put feet (at least a few inches) on the woofer side of this design and stand it up for a tall narrow tower.
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post #4 of 24
4/25/12 at 1:32pm
Thread Starter 
Quote:
Originally Posted by A9X-308 View Post

Without giving a budget, no. How much can you spend, now, for driver, amp, EQ and materials such as MDF? How big is your room?

I have all the tools and the MDF. As I mentioned in my post, my room is approx 13' x 20'. I would really like to keep the components to about $300-$400.

Are you sure you're asking in the right forum then?

Not sure. I see alot of DIY's but not alot of reviews on those to determine if people like the end product or not. I would also like to see if there are some surround speaker favorites in here that may be better than the Sten II's.

Quote:
Originally Posted by Jay1 View Post

http://stories.parts-express.com/sto...7/redirect.htm

You can use the woofer specified or replace it with the cleaner sounding and higher power handling RSS315HO-4. Use a plate amp up to 500 watts, depending on what your budget allows. You can also put feet (at least a few inches) on the woofer side of this design and stand it up for a tall narrow tower.

I like the idea here but it's a little more than I want to spend and it's a little large. I found a couple subs on Amazon that looked pretty nice for $250-$350 with really good reviews but I really want to build it myself.

Thanks.
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post #5 of 24
4/25/12 at 1:46pm
Quote:
Originally Posted by mathu126 View Post

I have all the tools and the MDF. As I mentioned in my post, my room is approx 13' x 20'. I would really like to keep the components to about $300-$400.

Dayton RSS390 and a plate amp will come in circa $300. Someone else would need to advise on the plate amp as I don't use them.
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post #6 of 24
4/25/12 at 2:05pm
I built super simple, under braced small sealed subs and I am completely satisfied with the SQ and output, and extension compared to $400 commercial subs. The best part is I can always build a larger ported sub with the same driver and amp if I get the itch for more output.

The energy s10.3 is the only under $300 sub I would even consider

Now that we know your budget and general size requirements, I'll put something together for you when I get home.
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post #7 of 24
4/25/12 at 5:03pm
Ok, here's a super simple build that will massacre anything available for $300 commercially in both output and "musicality".

Dayton DCS450 18"

Yung 300-6 with boost

3/4" MDF sheet (check your local stores)

You can get enough spray paint, glue, screws etc for $50 to finish the build at your $350 limit.

This is really simple, just build a box with 22" wide x 22" high x 16" deep outer dimensions (or deeper if you can fit it, but the shallow depth lets the sub hug the wall).

The attached pic shows you a sketch up of the enclosure and the brace you would place in the middle of the box, you can also take round 1" dowel rods (or scraps of mdf) and run them from front to back (and back to front) into the middle brace as much or as little as you would like. It's really that simple. Make a cut out for the amp in the back, and stuff the box with $3 polyfill pillows from walmart. Above 30hz output will compare to $1000 ID subs, below 30hz it will compare with $500 ID subs.

(20.4 on the brace should read 20.5)
LL
LL
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post #8 of 24
4/25/12 at 9:44pm
"Ok, here's a super simple build that will massacre anything available for $300 commercially in both output and "musicality"."

massacre? really? there are several subs with that kind of performance/pricepoint. the bic pl200 has been measured by ricci at data-bass to produce spl comparable to the model of your build. it is the ~$300 category, sometimes less depending on when you check prices.

------

mathu, the absolute best bang-for-the-buck subs are horn loaded subwoofers. the downside is that they tend to be large, but there are some smaller ones. subwoofers are all about tradeoffs. everybody would like a tiny, low cost, high sensitivity, 10hz bone crusher, but they do not exist. most commercial subs are ported and tuned in the 25-30hz region, with internet direct models coming in with lower tunings. $300 is a tough pricepoint to beat what you can buy commercially if you go with a standard design.
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post #9 of 24
4/25/12 at 9:49pm
Output scales up 6db above 30hz as this is showing 75 watts to simulate the max output of the boosted region

Hmm starting to look like you're taking every opportunity to pick my posts apart weird

edit: this sub stays under xmax as well, and will do the opposite of drop like a rock below 30hz when placed in a corner. Comparing to the PL200...

http://www.data-bass.com/data?page=system&id=47&mset=45
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post #10 of 24
4/25/12 at 10:43pm
if you post bad information that needs corrected. i will correct it. it's nothing personal.

"Output scales up 6db above 30hz..."

in model, the dcs450 in the ~3.5 cubic foot enclosure that you posted, hits a max spl of 115db at 50hz. the bic pl200 has been measured at 116db at 50hz.

above 50hz, we'd have to see a measurement because inductance can knock down the upper end of the bass and i don't see any inductance management in that driver.

you claimed that the dcs system will "massacre" all others in the ~$300 pricepoint. the data don't support your claim.
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post #11 of 24
4/25/12 at 10:50pm
The Bic drops like a rock after its 110db 50hz peak, and is reported to be tuned to 30hz. Nothing about that looks like it would be good for anything but rap music.


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post #12 of 24
4/25/12 at 11:18pm
"The Bic drops like a rock after its 110db 50hz peak, and is reported to be tuned to 30hz. Nothing about that looks like it would be good for anything but rap music."

max spl and frequency response are two different things.

eq can be applied to create any frequency response that you wish. max spl is just where the system runs out of gas.

the pl200 is a good little sub with good distortion numbers. i'd guess that it would find a home in a wide variety of systems, not just "rap".
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post #13 of 24
4/26/12 at 8:13am
This is all easy to see from the data bass test


The basic response is still really bad, 10db roll off from 45hz to 30hz



Distortion below 30hz is off the chart. Clearly any output below 30hz above 95 db is just distortion, as it's below tune.


I dont understand why you're only factoring max output at 50hz for comparison? EQ can flatten out most things but it eliminates headroom just like the 30hz boost does on my propsed sub. It also wont do anything below 30hz for the Bic. My propsed sub stays right at xmax with 300 watts in 3 ft3 at all frequencies until the amps HPF kicks in. Distortion should be good. OP is also placing this in the corner of a 13 x 20 room, which will boost the nice roll off of -3db 30hz and -10db 23hz
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post #14 of 24
4/26/12 at 10:08am
i just chose 50hz because it was above 30hz and above that level inductance can cause spl to fall off quickly depending on the sub. our modelling tools aren't yet there for capturing that effect, so you kind of have to turn to measurements in order to be sure.

the pl200 has a low pass filter that offers a variety of frequency responses. distortion does blow up below 30hz on the pl200, just as it does below tuning on all ported enclosures.

the model that you presented has the spl falling below 30hz at almost 20db per octave. room gain isn't going to help much to offset that. your sealed sub will do better under 30hz, but not by much.

and just in case it isn't clear, i'm not saying your design is bad. it is a good value and would serve many well. all my replies were just in response to your initial comment about there not being any commercial offerings that will be anywhere near as good of a value.
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post #15 of 24
4/26/12 at 8:11pm
Have to agree that the DCS450 is a remarkable amount of sub for the money. It often goes on sale for ~$100. Has about the same displacement as a typical "ultra-long-throw" 12" driver that would normally cost ~$150-200+, but has about 5dB better sensitivity. 100-200W is plenty to use the available Xmax in most enclosure designs... The large displacement and low power requirements easily make it one of the best value drivers you can use.

Regards,
Eric
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post #16 of 24
4/26/12 at 8:58pm
Quote:
Originally Posted by LTD02 View Post

i just chose 50hz because it was above 30hz and above that level inductance can cause spl to fall off quickly depending on the sub. our modelling tools aren't yet there for capturing that effect, so you kind of have to turn to measurements in order to be sure.

the pl200 has a low pass filter that offers a variety of frequency responses. distortion does blow up below 30hz on the pl200, just as it does below tuning on all ported enclosures.

the model that you presented has the spl falling below 30hz at almost 20db per octave. room gain isn't going to help much to offset that. your sealed sub will do better under 30hz, but not by much.

and just in case it isn't clear, i'm not saying your design is bad. it is a good value and would serve many well. all my replies were just in response to your initial comment about there not being any commercial offerings that will be anywhere near as good of a value.

I guess we're just going to have to agree to disagree. I see a horrible frequency response with nothing below 30hz from the bic. That's not something I would recommend someone spend money on. It only flattened out with the LPF set to minimum (It would be ok at the middle setting), which means you need speakers that can handle 50hz at 90+ db. That also completely eliminates its 110+ db output capability.

Every other sub in this price range offers nothing below 30hz just like the Bic.

This DCS450 sub is very undersized (op wants a smaller sized cheap easy sub) with 30hz boost, it will drop off. The output however is completely controlled, and is a "free lunch" vs subs like the Bic. 98db at 20hz before room gain is pretty good IMO, given the constraints.
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post #17 of 24
4/26/12 at 10:13pm
at this point, i agree we will just have to disagree. just about everything you said in post 16 is incorrect.
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post #18 of 24
4/26/12 at 10:51pm
The DCS450 in a sealed box around 3-4 ft^3 should be good for at least a full 10dB better than the bic PL200 at 20hz.

Based on just looking at the PL-200, and figuring the volume ~2ft^3, and the port to be ~4" x 15", that's a 31hz tuning frequency... Yes, it can play 20hz, but is probably limited to about ~20W before Xmax limitations, and the response would be likely in the mid 80dB range since it's mostly unloaded at that point.
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post #19 of 24
4/26/12 at 11:57pm
why are you talking about response below tuning in a ported cab?
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post #20 of 24
4/27/12 at 12:18am
Quote:
Originally Posted by LTD02 View Post

at this point, i agree we will just have to disagree. just about everything you said in post 16 is incorrect.

I want to just drop this, but I dont understand how you can say just about everything is incorrect?

I guess we're just going to have to agree to disagree. I see a horrible frequency response with nothing below 30hz from the bic.

An at least 6db 50hz peak, and a 10db drop to the 30hz tune. I dont see a problem there

That's not something I would recommend someone spend money on.

My personal opinion

It only flattened out with the LPF set to minimum (It would be ok at the middle setting), which means you need speakers that can handle 50hz at 90+ db. That also completely eliminates its 110+ db output capability.



The green is minimum and flat. The middle is yellow and looks decent, but it's 6 db down at about 57hz. The mains are going to have to keep up down here. The 50hz peak is also cut 6db, so that cuts its max output by that much.

Every other sub in this price range offers nothing below 30hz just like the Bic.

I haven't seen one

This DCS450 sub is very undersized (op wants a smaller sized cheap easy sub) with 30hz boost, it will drop off. The output however is completely controlled, and is a "free lunch" vs subs like the Bic. 98db at 20hz before room gain is pretty good IMO, given the constraints.

There's 2.5db of boost present at 20hz with my model. When the sub plays with 75 watts the response will look like the graph I posted earlier with 30hz being maxed out by 6db of boost. When output rises there's still at least double the power (3db) available at 20hz. Xmax is never exceeded with 300 watts in 3 ft3.
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post #21 of 24
4/27/12 at 12:26am
"I want to just drop this, but I dont understand how you can say just about everything is incorrect?"

that's not what i said. i said that just about everything in post #16 was incorrect and it is.
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post #22 of 24
4/27/12 at 2:12am
Quote:
Originally Posted by LTD02 View Post

why are you talking about response below tuning in a ported cab?

Because it is relevant to the comparison at hand. There is response below tuning frequency, it is just severally limited. Why are you asking this question?
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post #23 of 24
11/18/12 at 8:25am
Quote:
Originally Posted by Jay1 View Post

Ok, here's a super simple build that will massacre anything available for $300 commercially in both output and "musicality".

Dayton DCS450 18"

Yung 300-6 with boost

3/4" MDF sheet (check your local stores)


You can get enough spray paint, glue, screws etc for $50 to finish the build at your $350 limit.


This is really simple, just build a box with 22" wide x 22" high x 16" deep outer dimensions (or deeper if you can fit it, but the shallow depth lets the sub hug the wall).


The attached pic shows you a sketch up of the enclosure and the brace you would place in the middle of the box, you can also take round 1" dowel rods (or scraps of mdf) and run them from front to back (and back to front) into the middle brace as much or as little as you would like. It's really that simple. Make a cut out for the amp in the back, and stuff the box with $3 polyfill pillows from walmart. Above 30hz output will compare to $1000 ID subs, below 30hz it will compare with $500 ID subs.


(20.4 on the brace should read 20.5)
525x525px-LL-e2cfb2dd_vbattach244582.jpeg
525x525px-LL-4497364f_vbattach244585.png

Wow. This is a exactlyl what I've been looking for. I have a PL-200 and it really drops off at 50. I want to try this but I need to be able to go out to two other speakers. Would the Dayton SPA250 be enough to drive this beast?

Thanks!
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post #24 of 24
11/18/12 at 10:35am
based on the information reported at htshack, which comes from the yung engineer, this is probably about what you are looking at for response in that design.

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