technical question about advanced box design
02-13-2005, 12:11 AM
#1
1000 Watt CAFz'r
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technical question about advanced box design
Hi, this is for the mods, and what ever audio geniuses happen to grace this board. But my question is regarding advanced boxes, such as Dipole sub-boxes or transmission line enclosures. I was talking to this Audio guru here in Calgary (hes primarily home audio) but he said Transmission line boxes are pointless in a car, since automotive environments boost the low end freq.s from below 60hz or so, enough to render a t. line box pointless in a car. He said something simular about Dipole too. He also mentioned the idea behind horn loading speakers. In Pro. audio, which he does a lot of, he builds a horn for the speakers, since it apparently gives it a 3 db increase. Thats great for pro. audio, but a horn is way to big for a car. Would that 3 db boost also work inside a car? If so, then I'd like to have him build me one, so I can gain three dbs in a comp. without doing anything, that sure would be cool. but is anything here possible....
like what do you guys think about this?
here is a really cool website, that goes into great detail
http://www.diysubwoofers.org/dipole/design.htm
[ February 13, 2005, 01:12 AM: Message edited by: SPL donut ... ]
like what do you guys think about this?
here is a really cool website, that goes into great detail
http://www.diysubwoofers.org/dipole/design.htm
[ February 13, 2005, 01:12 AM: Message edited by: SPL donut ... ]
02-13-2005, 08:04 AM
#2
TLs can and do work well in car.. as the guy you talked to said, its probably not be necassary unless you want to get low with smaller speakers (like 8s or something)
You are also correct about horns... in a car they will simply act as a regular ported box... no point..
You are also correct about horns... in a car they will simply act as a regular ported box... no point..
02-13-2005, 08:59 AM
#3
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im not an expert on horns but i think the legnth of the horn for low frequncies would be very long, but i may be wrong. i have done 2 t/l boxes in car and they both used a morel mw162 and worked amazingly well, there was alot of trial and error with fill but in the end the results were a ton of low bass from a speaker that wasnt really designed for it. t/l's are also very big, the ones we built were almost 3 cubic ft for a 6.5", the cubic ft. isnt really the important thing in a tl box but rather the legnth of the chamber inside it, in the ones we did we tuned to 1 octave below the fs of the speaker, i shouldnt be talking about this, it makes me want to go build one and i dont have time right now. one other thing that makes tl's complicated is that there isnt a box program that can assist you, there are the basic mathematical calculations that you can do but the rest is trial and error, just get a bigger amp and more woofers if you want to go louder [img]tongue.gif[/img]
02-13-2005, 09:10 AM
#4
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As far as transmission line in a car. The biggest reason they dont work in a car is that a single 8" transmission line would be insanely huge and pointless.
A pair of 12's would be the size of a car.
plus for the most part it is guess work
A pair of 12's would be the size of a car.
plus for the most part it is guess work
02-13-2005, 09:48 AM
#5
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Aside from the volume that a TLine or a Horn takes up, one of the reasons they are difficult to make work in a car is both designs work best radiating into an open area.
A car will provide resistance at the opening of the mouth or vent which has to be compensated for in the design. As Dave found, in a TLine this would mean changing the length of the line or altering the density of the fill within the line. With a horn you would have to compensate likely both with expansion rates and with horn length - a tough thing to figure out and expensive to do by trial and error.
A car will provide resistance at the opening of the mouth or vent which has to be compensated for in the design. As Dave found, in a TLine this would mean changing the length of the line or altering the density of the fill within the line. With a horn you would have to compensate likely both with expansion rates and with horn length - a tough thing to figure out and expensive to do by trial and error.
02-13-2005, 12:33 PM
#6
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Holy smart *** batman, wow. I heard of someone building a TL box for a pair of 6.5" subs, the box gave 120DB at 22hz. or around there, but mid-low 20 hz range. I sure thought that was impressive.
But Dipole subs are really unique, they are long boxes, with the sub mounted on the front, but there is no back piece to the box,... its like a 5 sided box, which is all carefully designed and tuned, that link that I included at the top of the thread does into more detail. Does anybody have any experience and/or knowhow of how that works?
02-14-2005, 08:55 AM
#8
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Who says horns don't work well in cars???
http://www.billfitzmaurice.com/plans...7e7aa809916456
I'll be building one of these as soon as the MCM driver becomes not-backordered, and we'll see what an 8" horn-loaded driver can do with 300W. [img]smile.gif[/img]
http://www.billfitzmaurice.com/plans...7e7aa809916456
I'll be building one of these as soon as the MCM driver becomes not-backordered, and we'll see what an 8" horn-loaded driver can do with 300W. [img]smile.gif[/img]
02-14-2005, 10:02 AM
#9
^ it might work out with a small speaker tuned high... but generally speaking a horn loaded box will not work as its intended in a car...
You'd need almost a 8"x8" opening in the horn to be able to tune it to 30hz...
You'd need almost a 8"x8" opening in the horn to be able to tune it to 30hz...
02-14-2005, 12:44 PM
#10
50 Watt CAFz'r
Join Date: Oct 2003
Posts: 200
Well, I agree that for all intents and purposes a horn-loaded box in a car is impractical in theory because of physical limitations, but I think proper design can get an efficient horn without it being rediculously large. I mean the basic intent of the horn is to increase efficiency, so putting one in a car in itelf doesn't really affect the overall intent. Horn-loading plus cabin gain seems like good combo to me.
8"x8" is nothing... Do you mean 8'x8'???
You'd need almost a 8"x8" opening in the horn to be able to tune it to 30hz...
