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Let's talk some car audio.

SSSnail

SSSnail

Lifer
So I have this sudden interest in car audio and was thinking about doing something crazy, like design my own box. I did some searching on the interweb and came across this website http://www.diysubwoofers.org/car/. It talks about designs and calculations and when I read the calculation page I went 😕.

In laymen terms, can someone explain the calculation for the space requirement? I'm trying to come up with my own design that will not take up a lot of space yet can still perform. I understand that the space required is dependent on the individual woofer, just need a formula. An example is great.
 
You know, you could have just refrained from clicking on the "Reply" button. Or breathe.
Click to expand...

or he could have been 100% correct...which he is. different subs perform...well, differently. most manufacturers will specify the optimal box size for both sealed and ported applications (as well as tuning frequency for the latter). some will even go as far as to specify boxes for spl (most output) or sound quality (flattest frequency response). there is no generic formula.

are you talking about a standard rectangular box or something fancier? what's the max amount of space (either in length/width/height or cubic feet) that you have?

edit- time warp. yeah, you can calculate that stuff yourself if you have the t/s parameters for a specific woofer, but i'm not sure that's the question he was asking.

again, to the OP, you need to have a sub in mind before you start laying out box designs.
 
i'd say to go to the audio section and ask someone like YoYo. you'll probably get much better info (or just PM him or something) 🙂

IIRC, calculations for speaker requirements are "correct" as long as you input the proper thiels-smalls values, volume of the room, etc. but definitely ask someone better-informed than me! 🙂
 
Originally posted by: brblx
or he could have been 100% correct...which he is. different subs perform...well, differently. most manufacturers will specify the optimal box size for both sealed and ported applications (as well as tuning frequency for the latter). some will even go as far as to specify boxes for spl (most output) or sound quality (flattest frequency response). there is no generic formula.

are you talking about a standard rectangular box or something fancier? what's the max amount of space (either in length/width/height or cubic feet) that you have?
Click to expand...

Well, I do want to generate a meaningful discussion regarding designs. I was thinking more like the Bose's waveguide system for cars. So let's say an approximate required volume for a typical 10" woofer is 1.25 ft^3, if I was to design something with a ported design in mind and route the waveguide so that I don't have to use up the entire volume required, etc...

I can stuff the box, which would reduce the volume required, and how would that affect the waveguide, etc... I think there are information out there regarding how much stuffing can be substitute for volume; but what kind of performance will I have to sacrifice. I'm not looking to annoy the drivers next to me, just want to waste some time, if that's understood.

As I said, I'm pretty much 😕.
 
oh geez, you said the 'b' word.

i googled 'bose waveguide' and still don't know what it is.

http://www.bose.com/controller...waveguide_solution.jsp

some pretty retarded stuff on that page. it looks like a ported enclosure, assuming the that tunnel goes to the back side of the speaker (who the hell even knows, knowing bose it probably goes nowhere). anyone who knows his ass from a hole in the ground however, would realize that they could make the stereo half the size with the same result (which is to say, a bad one) if they just reduced the diameter of the port- which would also drasticly reduce needed length. it'd still be a stupid concept for that kind of stereo, though.

also, know that when you calculate the size of a box, the volume of the port is not included.
 
If you're looking for ACCURATE bass reproduction, it's better to go with a sealed enclosure rather than a ported one.
 
you truly are clueless to this whole thing.

First) Decide on how much space you have for a box.

Second) Research subs that perform well in that box size.

Third) Decide and install

Don;t forget - anything with a port generally needs a bigger box size and tuning a ported box aint easy at all.

PS: Don't forget the polyfill.



 
This is an extremely complicated topic.

Bose's "Secret" is simply a multiple order (6th possibly) enclosure.

You'll need to do a TON of reading, and frankly in the end you'll be better off just buying a good box that is engineered for the speakers you're putting in it. There's no simple formula to tell you the response you'll get from a given set of speakers and a given amp - there are a bunch of rules of thumb but none of those will get you all the way there.

Then of course, what type of box are you looking for? Ported, enclosed, bandpass?
 
I have tried lots of different sub arrangements and different box designs. The best thing i have found that works is letting the audio guy, who does audio for a living design you a system, going away saving the green, then letting the pros do the install.


I have install about 6 car audio systems over the years, and its really a pain in the ass

You should try your hand at designing the overall system.




Here is my current plan for my jeep

Head Deck


Front and rear splits plus 4 channel amp to suit

2 x 12 inch subs plus amps to suit


If your a hardarse then an under car neon kit and your away
 
Tell me the sub(s) you want, and I'll design you a couple boxes, to give you an idea of what you'd be looking at. I'll also need trunk measurements. If you weren't in CA I'd build it for you, ah.

I usually build and tune ported boxes, which tend to be much bigger than sealed, but I'm running sealed in my trunk because my subs didn't like the ported design. =/
 
Originally posted by: Sea Moose
I have tried lots of different sub arrangements and different box designs. The best thing i have found that works is letting the audio guy, who does audio for a living design you a system, going away saving the green, then letting the pros do the install.


I have install about 6 car audio systems over the years, and its really a pain in the ass

You should try your hand at designing the overall system.




Here is my current plan for my jeep

Head Deck


Front and rear splits plus 4 channel amp to suit

2 x 12 inch subs plus amps to suit


If your a hardarse then an under car neon kit and your away
Click to expand...

Any specific reason you're using the JL components? I haven't worked in audio in a while, but back when I did it you could usually do better for the $$$.
 
i was always impressed by the sound quality of the Jl Subs... prolly wouldnt use them for the splits.. what would you suggest?
 
Originally posted by: Sea Moose
i was always impressed by the sound quality of the Jl Subs... prolly wouldnt use them for the splits.. what would you suggest?
Click to expand...

What are you looking to spendd
 
Originally posted by: BlackTigers
Originally posted by: Sea Moose
i was always impressed by the sound quality of the Jl Subs... prolly wouldnt use them for the splits.. what would you suggest?
Click to expand...

What are you looking to spendd
Click to expand...

loads... within reason 😛

I would do stages

Head deck and splits (front and rear plus amp) first

then plan and save for 2 subs and amps second



quality at high volume is what i like
 
Originally posted by: SSSnail
You know, you could have just refrained from clicking on the "Reply" button. Or breathe.
Click to expand...

or you could spend a little time learning about what sub you need. i bought a kicker sub, went to the website and read the manual and understood(not on a professional level) how to design a box based off of their formula.


but in either case, kiss me between the pockets.
 
Originally posted by: manowar821
If you're looking for ACCURATE bass reproduction, it's better to go with a sealed enclosure rather than a ported one.
Click to expand...

I agree. Not only that, it is much easier to design a sealed box, and the margin for error is much greater. Your box size can be off by as much as 25% with little change in response. There are online speaker box calculators.

The sealed box will not be as efficient (loud) as the ported box, but will have better transient response. Amplifier power is cheap nowadays, so power is not a problem.

JL audio subs are good, although expensive. You can find better deals.
 
Originally posted by: DeePee
start reading the manual from whatever sub you have.
Click to expand...

Originally posted by: SSSnail
You know, you could have just refrained from clicking on the "Reply" button. Or breathe.
Click to expand...

Actually, that's good advice since they usually list out the parameters you need to shoot for.
 
Originally posted by: Gillbot
Originally posted by: DeePee
start reading the manual from whatever sub you have.
Click to expand...

Originally posted by: SSSnail
You know, you could have just refrained from clicking on the "Reply" button. Or breathe.
Click to expand...

Actually, that's good advice since they usually list out the parameters you need to shoot for.
Click to expand...

:beer:

that's how i learned how to build a box for a comp VR 15" sub a few months back. i took their formula and plugged in my own numbers.
 
Yup, just use the Thiele/Small parameters for the particular sub (Vas, Q, etc) and you will be able to find tons of software that will give you proper box dimensions.
 
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