so if installing 2 subs with a volume requirment of .75 cf each, if 2 subs are to be used in the same enclosure should the box be 1.5 CF or .75cf
thanks

 

also if the subs are installed very off centered in the enclosure will that be ok?

 

1.5cf and off centered doesnt matter

 

thanks, so is it better to have seperiate enclosures or keep them in a common enclosure

 

From my experience, it does not make a difference as long as both are the same and running at the same frequency.

 

thanks guys

 

Actually and with Slief permission, I need to correct something here. You do want to use separate air spaces for each enclosure.

I have been doing this for so long I cannot remember why but when Matt Borgart(probably the best installer in the world, really) and Eric Stevens(owner, founder, engineer, 3 times world champion, tuned probably half or more world champion cars ever) tell me to do something, even if I do not recall why, I do it without question

Besides it braces the enclosure and stiffer is always better

Rick

 

99% of people will hear no audible difference between separate chambers or one common one

 

Where did you get that statistic?

J/K

Since internal bracing should be done it is easier to put in a solid partition than cutting a hole in one so may as well do it anyway.

I bet more would know if they had a real system, tuned, built right, played a decently recorded track, etc.....

Personally I have never tried both ways as I prefer to not reinvent the wheel when probably the top car audio experts in the world tell me what to do, I seldom do it a different way.

(except A pillar tweeters, I do what one of the very top guys does not agree with. I just do what works the best for a given set of circumstances like those not wanting mids and tweets built into the dash or A pillars and do not want kick panels, not many other options as I have only heard a few cars with door mounted or sail panel mounted tweeters work that well. In a perfect world I would build kick panels or, mids and tweets up in the dash or pillars)

Rick

 

Separate enclosures are preferred, but there is a pitfall. RAAMaudio is right that it adds important bracing, but if not constructed very well you can have issues. The volumes have to be exactly the same. The walls have to flex the same (internal walls can flex differently than outside walls). The drivers have to be the same (these can vary depending on quality control).

One benefit of sharing a single space is that it sums the various imperfections. It is also lighter and easier to build.

Nevertheless, pentavolvo is right that most would never know the difference.

 

I can understand seperate enclosures and bracing. But we arent talking 500+ dollar speakers and 1000+ watts rms its just not gonna make a difference if you ask me

 

Great points, I always do things the best I can no matter what I am building so my boxes are always very solid, well braced, if multiple subs the volumes are identical, etc......and as low in weight as I can if for a performance car. Baltic Birch Plywood, fiberglass molded to fit the factory or shape where I can use it exactly the thickness needed.

I guess for those just pounding out any old box, shared air space is fine

Rick

 

not quite true when it comes to ported enclosures. If the driver is close to the port, it will unload faster than if it was placed further away. Which is why you'll see SPL competition guys putting the sub as far away from the port as they can.

 

I was just about to build a quad 15 ported home audio/theater sub with 4kw power but found a folded horn cabinet for cheap to try out. The ports would be far from the sub for sure! But, the dual 15, 62x39x34, 2kw sub is so loud, and musical, we love it and are going to refinish it and keep it in the living room, it will give you a foot massage on the other side of the house

Rick

 

That is wrong

 

Let me see your pics

 

Already moved to the next project

That thing was big, ugly, very loud, very clean but would not play super low, the horn length would need to be many feet longer to really dig down deep. The next house I have I am going to build a giant, super huge, colossal horn loaded system in the basement, crawl space or attic, we are talking something around 400 to 800 cubic ft, or bigger, maybe much bigger.

It did play low enough for most music and with authority but I wanted something smaller, cleaner looking, etc...so just put four single sealed 2 cube units in its place, ID15's for subs, PE prebuilt enclosures ($400 shipped, not worth my time to build them for that price) and running a single PE SA1000 amp for now as it has a very good crossover, EQ, etc built in though I am probably going to replace at least some of the Op Amps and maybe the high pass frequency.

I have the amp opened up right now to install a sub out as have two 1,800 watt Pro Audio amps on the way, very nice ones. I bought them barely used for a great price, was going to get just one to run two subs and run the other two on the PE amp, just turn on the Pro Audio amp when we want to rock the place, etc...but I might run them both now instead, will do some listening tests then decide. I can always use one in the band room if not both on the home audio system.

I also have a Crown ce2000 2kw amp butt might sell it since I just bought the other amps.

I would practically give away that huge enclosure I just pulled out of there, just charge half off for the barely used subs. I put 2.5-3 packs of BXT II and 18 ft of 2x2 angle iron in the enclosure, outside, etc to stiffen it up, it is quite heavy now! pulling the subs, back wall to get to them, angle off, etc to move it would make it quite easy to move(compared to as it is).

I would put it in with the band system but does not fit down the stairs and we are putting this place up for sale soon anyway.

No pics, I am not great about posting them, to much time on the computer, some days 14-hours!

Rick

Rick

 

so you do not even have one or tried one. cant take a pick and you want to build my sub box.

 

Don't forget driver displacement, and if you sport a pocket protector you can add in wire displacement and the protrusion of the mounting screws displacement too.