What should I do first, mains or subs?

[Andy Shoppa]

I'm pretty new to this site, but I've built plenty of sub enclosures, most of them in high school shops class for other people. I've decided that I really need to work on 2 aspects of my current audio set-up: the mains and subs (what else is there?) As of right now, I cannot decide on which to tackle first.

My mains are 3 way 12" cerwin vegas that I got at best buy about 8 years ago. They were "awesome" when I got them, but I was 16 and just wanted something loud.

My sub consists of 2 15" JBL GT subs and 1 15" Orion XTR3 sub (car drivers), in about a total of 18 ft3 sealed enclosure. Powering these beasts are a Pioneer SA-7800 amp and an old Optimus receiver. Pretty great, huh? Well here's a quick sketch of the way my room is set-up:



Yes they are in the closet of a bedroom. In the corner of the sofa, I have measured 114 db at 22hz, and it will go 120 with music (rap) so it get's plenty loud. And I've got the response down pretty flat with the Behringer Feedback Destroyer, so it really doesn't sound that bad. But I don't have anything to compare it to.

The mains will be the Dayton RS TWMM using Dennis Murphy’s xover, that much I know. The subs, well I wanted to do a Tumult, but now I am looking more at the RL-P15, as in 2 in a larger vented enclosure, somewhere around 10-15ft3 or so. Or maybe the 15" Dayton Titanic. For an amp, probably the EP2500.

So what do you think I should do first? I'm leaning towards the sub, just so I can get back into building so hopefully I won't mess up on the Dayton RS's, but I know the Dayton RS TMWW would be a bigger improvement over what I have now.

[jonathanb3478]

Well, if I were you I would get the mains done first.

I could see where you would want to warm up on the sub construction, before tackling the mains. Either way, good luck!

[ThomasW]

A high performace sub will be the easiest to build, so that's where I'd start. Once your woodworking and problem skills are warmed up move on to the mains

[Andy Shoppa]

Yeah I'm probably going to do the sub first. I may try and "copy" steve nn's dual RPL unit, but the dimensions will have to change, It'll need to be approx. 38" wide by 17" deep by whatever it takes high. A 20ft3 like his would be approx. 65" tall, which is a little too tall. I was thinking of making something around a 15ft3 which works out to about 48" tall, which is a lot easier and will be easier on the wallet as getting more wood per 4x8 sheet.

A few quick ?'s

1) Is there anything wrong with 2 RL-P 15's in a 15ft vented enclosure tuned to 18hz? I only can run it in winISD pro, as I cannot get unibox to work on my computer.

2) How bad is it if I use a 10" port in a box that is only 17" in diameter?

3) Should I build this to fit in the closet like my last sub, or should I corner mount it where the bed is at?

4) Assuming I closet mount it again, I only have about 5-6 inches between the drivers and the closet wall, is this hurting my response or helping? Like I said before I have a really strong output in the corner by the sofa nad along that wall, but in the middle of the room there is basically no sub output at all.

5) Besides Acoustic Visions, where is the best place to order the RL-P15 4ohm from?

Thanks for the help guys, I'll probably be ordering them here in the next couple of weeks and starting on the construction shortly after. I'm sure I'll be posting along the way too so look forward to more of my dumb postings and pics!

[ThomasW]

1) Is there anything wrong with 2 RL-P 15's in a 15ft vented enclosure tuned to 18hz? I only can run it in winISD pro, as I cannot get unibox to work on my computer.

If you have Excel before you load Unibox, start Excel and and enable macros. Then load Unibox.

2) How bad is it if I use a 10" port in a box that is only 17" in diameter?

I don't understand this one???

3) Should I build this to fit in the closet like my last sub, or should I corner mount it where the bed is at?

Depends entirely on which location sound better.

4) Assuming I closet mount it again, I only have about 5-6 inches between the drivers and the closet wall, is this hurting my response or helping? Like I said before I have a really strong output in the corner by the sofa nad along that wall, but in the middle of the room there is basically no sub output at all.

You certainly don't want the drivers or a port that close to a wall

5) Besides Acoustic Visions, where is the best place to order the RL-P15 4ohm from?

It's cheaper directly from www.soundsplinter.com

[dyazdani]

2) How bad is it if I use a 10" port in a box that is only 17" in diameter?

Thomas,

I think he is asking about the port diameter vs. box depth. He said he wanted a 17" deep box (I guess to fit in the closet?) so he's wondering about a 10" port in a 17" deep box.

One issue I see is clearance between the port and the driver. I guess if you make it a tall box, then possibly the port tube will be short enough so you can put the driver(s) at the bottom.

[Andy Shoppa]

Thomas,

Yeah the 10" port in a 17" box question was just me wondering how adversely it would affect performance, since there will be less than 3" between the sides of the port and the walls of the enclosure.

As far as the 5-6" of space between the speakers and the wall, how is that really any different than having a down-firing sub in a corner?

I don't have excel, I have Microsoft Works, which has a spreadsheet program, but will not let Unibox run.

And I placed the order today with Soundsplinter, so the speakers should be on their way here as soon as my money order gets there.

I'm going to try moving my current sub to the location where my bed is, just to see what the difference in sound is, but I think I'll be doing another closet sub, unless I can get talked out of it.

Thanks for helping me out guys

[Andy Shoppa]

There's what I came up with in WinISD, 13.5 ft3 internal volume tuned to 18hz and 20hz. From that compairison I'd go with the 20 hz, mostly because the port would only be 31.7" long instead of 40.9".

Is there any real benefit from tuning to a lower frequency, such as say 12-14 hz? All id does in ISD is really mess up the curve. I'm not overly concerned with response below 20hz anyway.