Advanced sub Enclosures

[Ryan]

So I know there are a few audiophiles on here.

I'm bored of my simple sub box configuration. Its two drivers, in a single unit with a divider. I am quite good with Autocad and woodworking. I can build any flat sided shape imaginable.

I was simply wondering, are there certain ways that (theoretically or not) work better than others?

Some ideas I have and have seen...

driver centered
Duh

Pointed rear/pyramid


driver off to the side


oblique front


oblique rear

oblique side

some custom fitted to be rear seats

I wonder about two positioned centred on opposite ends of a rectangular box... firing in or out & 180 out of phase.

What are the advantages/what decides if a sub is designed for a ported or sealed enclosure(s)?

I understand that oblique sides (or at least having all three dimensions different) is an advantage as it eliminates resonant tones.

Any ideas or comments?

Thanks guys

[chew*]

For the best sound the KISS ( Keep it simple stupid ) method always works best, the more intricate the box design the more loss of frequency reproduction. If your really looking to get the most "sound" out of an enclosure however you can try this. Build a simple rectangular box oversized, get yourself some fiberglass and commence rounding out the inside of the box so there are no square edges, It doesn't have to be perfectly round just transitional so the sound rolls around versus bouncing. Sand down the surfaces as smooth as possible till you have a glass finish, After that paint it with a high gloss oil based paint. This should net you higher output whether ported or sealed and boost you subs efficiency, after all sound is round not square. In SPL vehicles this can net anywhere from 1/2 to 3db higher providing that you did not compromise the overall volume required by the sub ( etc built the enclosure oversized to start ). In a sound quality application you should lose nothing in frequency response.

Its also best to keep both speakers firing in the same direction or in phase if you will, intricate angles or out of phase speaker placement always results in cancelation.

If your really into experimentation however might I suggest earthquake subs and a passive radiator setup.

[Ryan]

About time...

chew*

I had meant to PM you, because I remembered reading your posts earlier... but I couldn't remember the name

Thanks for actually replying. 81 views later.

I understand physics moderately well, or so I like to believe, and I agree with all you say

what I am curious about is... firing opposite directions, 180º out of phase in a sealed inclosure. Maybe a tubular one?

[chew*]

Thats exactly what a passive radiator setup is designed for. You have an actual sub, then you have the "radiator" basically an unpowered shell of a sub. etc no magnet its just a suspension sytem so to speak. Only company that I know still does this with car audio is earthquake though, its far more popular with home theatre gurus.

Doing it with 2 actual subs however ( 180 ) would have a negative effect, unless you wired the phase of one of the speakers backwards, this would act similar to a double stack which has been done but is far from efficient.

[onlytrueromeo]

I agree, simple seems to be better. I have a nice box I made the stretches most of the way across the back of the hatch...no its not the best design since its alot longer than it is thick, but it fits the car well and still sounds nice.

Chew, would more power to a sub increase the SPL that much more or increase the response that much more...reason I ask...I have a JL 12W3V3 powered by only a JL 250 monoblock and it sounds great to me, but its definitely not close to the capacity of the sub. If I were to upgrade in the future, would you recommend the 500 JL amp? What should I expect?

I like to listen to a well balanced system...I dont just like extreme bass. I have 2 polk MOMOs up front powered by a JL 300/2.

[Ryan]

what are boom tubes, and how do they work? I've seen one in some guys RX7 at school, and for being so tiny, its impressive...

Yes, I could google this but I want opinions at the same time...

[chew*]

I think they are designed on the same premise of a bazooka tube.......Bazookas are impressive depending on the acoustics of the car, toss them in a typical trunk and they are an epic fail, toss them in a typical hatch ( rx-7 ) and they sound impressive. That said just because a "setup" bangs in one car doesn not mean it will sound good in yours. Acoustics of cars are very different, I've tried every possible way in the mx-3 and by far just removing everything in the hatch including the spare tire and tire well cover and a box built tight against the seat not extending over the spare tire well sounds best ported rear and fired rear.

The only thing that sounds better is a bigger box mounted where the seat is that does not extend over the spare tire well, measure distance from edge of spare tire well to end of hatch, build a box with the exact same depth, this will couple the soundwave to the car. Then depending on SQ or SPL tune the box accordingly, for spl 52hz, for SQ 25-30hz.

The recipe I used for SQ was 2 12" subs in the 500-600 rms range and a single 1200.1 with a single center fired port. This was good for 147-149 db. The recipe for spl is a simple large box with a port fired rear, port on driver side sub on pass side, this wraps the pressure around the back of the car on the drivers side and slingshots it around to the passenger side right to the dash/windshield where the meter is mounted.

With a passive radiator design you can get away with a single sub, get the output of a ported enclosure with the frequency response of a sealed at the cost of only cubic volume of the box, problem is the only company that i know still makes passive radiators is earthquake.

[chew*]

I agree, simple seems to be better. I have a nice box I made the stretches most of the way across the back of the hatch...no its not the best design since its alot longer than it is thick, but it fits the car well and still sounds nice.

Chew, would more power to a sub increase the SPL that much more or increase the response that much more...reason I ask...I have a JL 12W3V3 powered by only a JL 250 monoblock and it sounds great to me, but its definitely not close to the capacity of the sub. If I were to upgrade in the future, would you recommend the 500 JL amp? What should I expect?

I like to listen to a well balanced system...I dont just like extreme bass. I have 2 polk MOMOs up front powered by a JL 300/2.

In theory in order to gain 3db which would actually be twice as lound as your current setup you would need to A: double your cone area and B: double your power. This of course is in a perfect world, the best case i have seen from doing this is 2.5db gain. That said realistically doubling your power may net a 1 db gain, so it would be a matter of whether the cost is worth the gain to you. IMHO it would be cheaper for you to just get a W1 for the amp you are using now. and would prbably net you the same gain for about $120. versus the $600 amp upgrade.

[onlytrueromeo]

Thats what I was thinking, but I love my W3! Im happy with it now, I was just wondering if I could increase the response rate since 12's are inherently slower than 10's.

Maybe in a few years when I need to upgrade to newer equipment again, I will figure out something better!

[chew*]

I love the sound of 10's, used to run 6 old school 10w6 in a CRX sealed.......150db+ and clean to boot.

Then i got into SPL, JL isn't as efficient in those applications and anything over twice the rated power scorches them, I ended up with memphis which i put quadruple rated power into and they play all season long for the most part.

Anyway nice to drop in, I guess breaking my ribs skateboarding has it's benefits, I get to catch up on all the forums I belong to.

[onlytrueromeo]

Ouch on the ribs! I currently have 1 broken rib, but its almost healed. Sneezing SUCKS.

I like SQL over SPL right now, but I like to have a bit of both worlds. I'n not looking to win a competition, just keep things nice for a DD.