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DIY sub help

post #1 of 19
Thread Starter 
Hi everyone, newb here.

I've been reading/searching here for a while and it seems the more I read, the more confused I get. I have built myself a little man cave HT in the corner of my finished basement. I currently have a 3.0 system and would like to add a powered sub. I was flip-flopping between retail and diy. But I've settled on diy for bang/buck reasons. My budget is between $400-$500. (less is OK) I'm confident in my woodworking skills. Size isn't a huge concern but I don't want anything outrageous, 8ft^3 is probably the biggest I'd want. I expect clean (not boomy) bass that you can feel and not hear, but I understand the limitations of my budget.

I was considering dual 12s or maybe a single 15. But I'm getting in over my head and I could use some guidance with regard to drivers, sealed vs ported, amps. I don't want to make a $500 mistake and have to start over.

I attached a simple floor plan (not exactly to scale) of the basement room(s). The HT area is on the right side of a long room which is open to smaller room and a stairwell. The walls are covered in sheetrock, the floors are padded and carpeted. The ceiling is a combination of suspended tiles and sheetrock. I labeled 3 spots a subwoofer might fit, 3 is the tightest fit with the current couch.

Current setup: Polk CS2 and M70s / Onkyo TX-SR709

Intended Use: 40% TV, 20% movies, 40% games, 0% music.

Room info: ~3500 ft^3

Basement HT.pdf 12k .pdf file

thanks in advance

Tom

edit for clarity
Edited by tommy1403 - 11/26/12 at 12:12pm
post #2 of 19
I would do multiple boxes to get a more even response. If you could put a sub in all 3 positions that would be ideal.

3 of these: http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-190 will be $300. An iNuke3000 dsp for $350 and $100 for wood will get you there, but that's over budget.

3 of these: http://www.amazon.com/Infinity-Reference-1260w-1200-watt-High-Performance/dp/B0028AVGEO/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=2FNQCEE0HADXC&coliid=I2ULU575RTHCPM is $171. Add another $250 for an iNuke 1k dsp and $100 for wood. That's closer to budget. Or skip the dsp for now and get the regular 3k for $300.

Plan on doing LLT ported boxes if you can spare the space since you are trying to pressurize 3500 cu ft.
post #3 of 19
^ IMO the Dayton 15's mentioned above are the best deal going right now. USA made, good output and sound quality for 100/driver. If size isn't an issue, maybe consider 2 drivers each in a ported box around 6 cubes. The inuke3000dsp and/or a Beringer EP4000 from wally world are great budget amp choices as well.

2 daytons - 200
Amp - 275 to 350
Wood and Glue - 65 to 130 depending on type and enclosure size choice
Paint - 10 to 70 depending on the finish you want
Polyfill or wal mart pillows - ~35
Terminals - 15

Slightly over budget? Yes, and you can always start with a single driver if need be.
post #4 of 19
Thread Starter 
Thank you for the replies. What are the size requirements for an LLF box? (I can't seem to find any plans) I see you're both suggesting external amps vs plate amps. is that for cost savings or for increased power? I hadn't considered external amps or processors as I don't have anywhere to mount them. (media console is full). I had notions of a bash plate amp and dayton 12s or 15s.

I have been tossing around the idea of an Epik Legend now that it's on sale. I just don't think it will be enough for my room.

what's wally world?
post #5 of 19
LLT (Large Low Tuned) is a big box. 7-10 cu ft / 15. You will be looking to tune to 11-18hz.

With multiple subs a pro amp will be more economical long term. Even if you only do 2 DVC 15's plus an iNuke for now you can add 1 or 2 more subs later without needing another amp for each one.

However, the bash 300w is $112 right now. 2 of those + 2 $99 DVC's would be a cheap option, but no DSP and no extra power for a later upgrade.

So it comes down to this:

A) If you want dsp and the ability to run up to 4 subs for the cheapest long term cost you should get the pro amp and get ready to mod the fan.

B) If you don't want to mess with that now and just want to get your feet wet with a DIY project you can get a bash for each sub that will fit into your budget right now. Add a mini dsp later when you get ready to do some testing with REW.
post #6 of 19
Quote:
Originally Posted by tommy1403 View Post

what's wally world?

two possibilities...

1) a slang term for Walmart
2) a fictional amusement park from Vacation (movie with Chevy Chase)
post #7 of 19
Thread Starter 
haha, I am hoping he wasn't talking about buying a $300 amp at walmart.
post #8 of 19
I'm guessing it was a misprint, I don't think Walmart sells pro audio gear. Maybe they do online but I don't think so.
post #9 of 19
I stand corrected...

http://www.walmart.com/ip/Behringer-Stereo-Power-Amplifier/17656015

I didn't see any inukes, but they do sell pro audio gear. Orders seem to be fulfilled by another company though.
post #10 of 19
Quote:
Originally Posted by nograveconcern View Post

LLT (Large Low Tuned) is a big box. 7-10 cu ft / 15. You will be looking to tune to 11-18hz.
With multiple subs a pro amp will be more economical long term. Even if you only do 2 DVC 15's plus an iNuke for now you can add 1 or 2 more subs later without needing another amp for each one.
However, the bash 300w is $112 right now. 2 of those + 2 $99 DVC's would be a cheap option, but no DSP and no extra power for a later upgrade.
So it comes down to this:
A) If you want dsp and the ability to run up to 4 subs for the cheapest long term cost you should get the pro amp and get ready to mod the fan.
B) If you don't want to mess with that now and just want to get your feet wet with a DIY project you can get a bash for each sub that will fit into your budget right now. Add a mini dsp later when you get ready to do some testing with REW.

(also noob here looking into first DIY)

What does the DSP provide? Why would you want it?

How many DVC 15's can be run off a EP4000 vs EP2000 vs iNuke?

What's REW?
post #11 of 19
Thread Starter 
walmart, who knew?

There really isn't space for future upgrades or sub additions, at least not while we're living in this house. So this will be it for the next 5 years or so.

As for DSP and REW, I thought the ONKYO would EQ the sub with Audyssey. That's what i read, which is why i got the 709 vs something cheaper. Or is DSP something different? I'm with vivatech here, kinda lost.

I think i should reevaluate my expectations for this endeavor. I really just want a sub or 2 (at most) to make my HT experience more complete. Instead of spending a lot on an Empire or Outlaw, I was hoping to get something close by DIY. The more I think about it, the 8 cube box is going to be too big. I would rather have 2 smaller boxes in the 4 cube range

I'm just trying to be realistic with what I want to accomplish. A few months ago I was looking at a single BIC F12, then a PA-150. Now I see I can do better with my money.
post #12 of 19
Quote:
Originally Posted by vivatech View Post

(also noob here looking into first DIY)
What does the DSP provide? Why would you want it?

DSP is a programmable EQ. If you do a sweep of your frequency response in room you will know why you want DSP.
Quote:
Originally Posted by vivatech View Post

How many DVC 15's can be run off a EP4000 vs EP2000 vs iNuke?

As many as you want. The law of diminishing returns seems to indicate that 4 would be a good place to stop though.
Quote:
Originally Posted by vivatech View Post

What's REW?

Room EQ wizard. It's a free RTA software.


Quote:
Originally Posted by tommy1403 View Post

walmart, who knew?
There really isn't space for future upgrades or sub additions, at least not while we're living in this house. So this will be it for the next 5 years or so.
As for DSP and REW, I thought the ONKYO would EQ the sub with Audyssey. That's what i read, which is why i got the 709 vs something cheaper. Or is DSP something different? I'm with vivatech here, kinda lost.
I think i should reevaluate my expectations for this endeavor. I really just want a sub or 2 (at most) to make my HT experience more complete. Instead of spending a lot on an Empire or Outlaw, I was hoping to get something close by DIY. The more I think about it, the 8 cube box is going to be too big. I would rather have 2 smaller boxes in the 4 cube range
I'm just trying to be realistic with what I want to accomplish. A few months ago I was looking at a single BIC F12, then a PA-150. Now I see I can do better with my money.

Yes, Audyssey multEQ XT does eq the sub range. However, as I understand it, it only chops off peaks in response. It's not going to boost your sub 30 hz range to get it flat or fill in a wide null from a room mode.

DSP gives you a lot more control. It's your choice if you want it right now or not, and you may never feel the need to add DSP, but if you do you can always add a mini dsp later.

If you want to say in budget and just build 2 nice subs then just do the 2 bash 300's and 2 DVC's. You can build a pair of 5cu ft / 18 hz boxes for them. I think you will be biggrin.gif
post #13 of 19
Thread Starter 
Quote:
Originally Posted by nograveconcern View Post

If you want to say in budget and just build 2 nice subs then just do the 2 bash 300's and 2 DVC's. You can build a pair of 5cu ft / 18 hz boxes for them. I think you will be biggrin.gif

Great, that sounds like a plan. Would those boxes be sealed or ported? Could you direct me to a previous build I could learn from? thanks again
post #14 of 19
Quote:
Originally Posted by tommy1403 View Post

Great, that sounds like a plan. Would those boxes be sealed or ported? Could you direct me to a previous build I could learn from? thanks again

Because of the size of your room we were talking ported.

5cu ft @ 18hz:
24" cube, 3/4 stock with two 39" lengths of 4" pvc for ports (you will have to have an elbow in there), flare the outside w/ a round over router bit. A double baffle on one side. Bracing inside using a combination of 2" strips along the walls and dowels or strips of wood connecting opposite sides.
post #15 of 19
Thread Starter 
thanks, ngc. Does it matter if the boxes are front or down firing? I've been playing with WinISD, it's pretty cool.
post #16 of 19
Quote:
Originally Posted by tommy1403 View Post

thanks, ngc. Does it matter if the boxes are front or down firing? I've been playing with WinISD, it's pretty cool.

Yes, down firing has the potential to sound slightly different than front. Either configuration is fine though.
post #17 of 19
Quote:
Originally Posted by tommy1403 View Post

thanks, ngc. Does it matter if the boxes are front or down firing? I've been playing with WinISD, it's pretty cool.
Down firing gives lower THD, as the above bandwidth harmonics that contribute to that THD don't go around corners as well as the in-bandwidth lows. If you're really adept at modeling you also can incorporate the space between the cab and floor into the cab, for bandpass loading.
post #18 of 19
Thread Starter 
OK, I want to make it as future (child/dog) proof as possible, down firing will hopefully help that. I am looking to modify Rhythmik's free DIY plans into a 5 cube box with the correct port size and length. Would that work? Does it matter if the ports point down or forward?

Bill, I am not very adept at modeling. But I'm becoming more and more familiar with WinISD. I played around with modeling a bandpass box (both 4th and 6th order) with the front chamber as the area between the cab and floor? I'm sure that was the wrong way to do it.
post #19 of 19
Quote:
Originally Posted by tommy1403 View Post

I played around with modeling a bandpass box (both 4th and 6th order) with the front chamber as the area between the cab and floor? I'm sure that was the wrong way to do it.
That's the right way to do it, keeping in mind that there are no walls on that front 'chamber', though you can do that too. But an advantage to using four legs and no walls is that you can fine tune response by adjusting the leg height.
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