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View Full Version : Is your typical square enclosure the BEST design for SPL



snb778
12-15-2004, 01:15 AM
I was just wondering if the square or rectangle enclosures are the best design you can possibly have, because I was thinking about the R.F. SUV that has those 2 18's in fiberglass enclosures the shape of a turbine...would this work better, or even just a cylinder design? Anything else?

bcarpenterfhl
12-15-2004, 01:59 AM
from what i've read two or more parallel sides can create potential for standing waves (which are bad), so a cylinder type enclosure may be beneficial.

80_Cutlass_mn
12-15-2004, 02:47 AM
The cylinder type of enclosure your speaking of is called a tranmission line enclosure. Theyre not too difficult to build but they have to be very long usually to be tuned right. Im sure someone else who can elaborate more on the matter of TL enclosures will comment later.

Shugarra
12-15-2004, 04:30 AM
The cylinder type of enclosure your speaking of is called a tranmission line enclosure. Theyre not too difficult to build but they have to be very long usually to be tuned right. Im sure someone else who can elaborate more on the matter of TL enclosures will comment later.

A transmission line enclosure is basically a special ported box. A cylindrical box can be sealed or ported or probably tl'd, although I've never heard of one personally, it's definitely not just a transmission line. Transmission lines are usually 1/4 wavelength of tuning frequency in port length and have slanted ports to try and avoid wave cancellation, not greatly suited for car audio because of their size.

snb778
12-17-2004, 05:51 PM
I am interested because im throwing together ideas for my next install and was thinking it would be bad *** to have 1 cylindrical (if thats a word) enclosure with ports on the sides blowing the air at my amps as sort of a self cooling method

80_Cutlass_mn
12-18-2004, 03:17 AM
If a TL enclosure is in fact ported, it is not ported in this way, more rather it is the same as sticking a subwoofer in one long port tube with the end open. Tuning involves changing the length of the pipe in which the subwoofer sits (round port effectively). The longer the port or TL enclosure, the lower the tuning. The shorter, the higher the tuning. This is why they must be so long. Because in a TL enclosure the air waves dont have a box to sit in so to speak before it leaves the box through the port, the whole enclosure is as I said, a port in itself so the air waves are able to leave the TL faster than a typical ported box. Hence the reason why they must be so long as to give the travelling air wave enough time inside the tube before leaving so as to not cancel the front wave out too soon.

bigred78797
12-18-2004, 11:26 AM
not neccessarily, you can have a transmission line box with a area of volume like your standard ported box. And yes they can be built in a snell shell type enclosure.. it is just very difficult to get the shape correct. They can also be built like 80 Cutlass decribes as just a sub in an open port. TL can also be made without a taper in the Port. And putting the sub in a " box with a port coming out of it " if designed right acts as a low-pass filter for the port. But to answer the original question yes you can make the box in the shape of a turbine... it has been done before. Yes your idea would work as long as you don't have the ports blocked in any way shape or fashion as that may cause un wanted port noise.

Raven
12-18-2004, 06:37 PM
To answer the question, in the world of acoustics, a square enclosure is about the worst thing you can have. Idealy, you'd want a spherical enclosure. It's not very feasable yet.

snb778
06-30-2005, 03:31 PM
I saw an enclosure that was pretty cool the other day...this kid paper machetted over a huuuge balloon, then fiberglassed over it...causing an egg shaped enclosure

btnhfan
06-30-2005, 04:23 PM
Orbis audio has those orbs in sphere carbon fiber enclosures.

psych0ticnemes1
06-30-2005, 04:45 PM
but rectangle enclosures sound fine :/

abcheng
07-01-2005, 06:34 PM
sonotube? hehe

Raven
07-04-2005, 10:41 PM
I saw an enclosure that was pretty cool the other day...this kid paper machetted over a huuuge balloon, then fiberglassed over it...causing an egg shaped enclosure

That would in theory be the best possible design for a sealed enclosure. There are also ported enclosures in the same fashion called "Halo Ported" enclosures.



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Imagine that shaped completely round an in 3d. Braces are made to hold the intnernal enclosure in place.

JimJ
07-04-2005, 10:50 PM
There's some iffy things going on in here.

A transmission line is nothing more than an enclosure with "port" that's a quarter-wavelength long...tapering to usually Sd or 2x Sd. A "mass loaded" TL is stuffed with varying amounts of polyfill (held in place with netting), and the line is "tuned" by adjusting the stuffing until the proper frequency response is achieved. They usually aren't cylinders - those are Sonotubes, as another poster pointed out. The prime advantage of Sonotubes is that a cylinder is much stronger for a certain wall thickness, and you can get more volume for the same floor space - Sonotubes used for concrete pouring are around half an inch thick, and are stronger than comparable MDF of that thickness.

http://t-linespeakers.org/

Didn't Gary Biggs a few years ago build a glassed spherical enclosure for the L7 used in the SQ judging part of his install? I remember seeing something like that.