help!subwoofers enclosures and crossovers!

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ok.
i am about to enbark on my first diy project.
i am planning to build a hometheater subwoofer.

here is my problem...
1. what the hell is a crossover and why is it so important?
2. are the dementions of the enclosure realy important or is just the quibic feet?

now....
i am planing to use these components...

1. Blaupunkt PCwg120 (12 in. woofer 200w RMS 600w peak)
2. parts express 250w subwoofer amp
3. a self constructed vented enclosure (2.0 qubic ft. with singil vent)

what else do i need....
i am a new be so please explain in detail.........
and are these components ok for a first time project on budget?

dont be ***** and relpy to this i realy need help......

thanks,
slice
 
ok, firsts things first, have u already bought the blaupunkt subbie?

i ask this because it is prolly not recommended to use a car sub driver for home theatre application. If you have, then its still good, if u havent, then a Shiva, or Dayton might be more suited.

a crossover is used to filter sound and direct it to where it needs to be used, ie, high frequencies are directed to a tweeter, low frequencies are to a woofer etc.

the dimensions of your cabinet will determine the cubic feet internally, plus dampening, less bracing

the parts express sub amp is a good choice

if u dont already have the blaupunkt tell me, ill run some sims and get u headed in the right direction, with a little help from Audiofreak i hope ;)

what type of music would u be listening too (plus HT i know) would it be jazz? classical? or if ur like me, slipknot, korn, superheist, fuel etc?
 
i have not baught anything yet but the $200 is burning a hole in my pocket!

i would like any advise you can give me on subwoofer enclosure design and crossover stuff.... and a few q's doesent the amp have a built in crossover....?

i would like to get some more details on enclosures as well as subs....

i chose the Blaupunkt PCwg120 mainly because of the frequency responce and the price....
y would it not be a good choice?
it sounds great in my friends car.....

well i would like to see some more posts so i can get this progect going......

note this is my first diy project....


thanks,,,,

keep up the posts!
 
the cubic feet is important, but so is the dimensions, ie, large side panels ideally shouldnt be parallel, this is to reduce standing waves.

car subs tend not to be suited to home theatre use, they are designed to achieve something completely different, although in theory it should be the same.

all enclosures for subs should be a minumum of 1" MDF, preferably 33mm if u have the space, strength to lift the thing.

is your budget $200 all up??

some amps have a high/low pass, which is a crossover essentially.

how much space do u have for a sub?
 
diyAudio Moderator Emeritus
Joined 2001
If you are going to get the parts express sub amp, you already have your crossover, as it is built in.

I am not familiar with the Blaupunkt subwoofer.

The dimensions of your subwoofer are not that important, as the sub will not be playing above 140 Hz anyway. Dimensions of the box matter more with full range woofers that go up to 500 or 1,000 Hz. Unless you are going to get extreme-like building a tall 8 foot long tube or something-the cubic feet is really what matters.
 
One thing to be careful of when using a car sub in a home system is that the car sub was designed to work in the small confines of car. It needs that huge cabin gain to get flat deep bass extension. When you take it out of the car, unless you stick it in a huge enclosure ported fairly low you're not gonna get much extension out of it. If you really want some good results my suggestion is that you save up about another $70-80 and get a Shiva or Tempest from adireaudio.com it'll go great with the amp you mentioned. If you're money is burning a hole in your pocket as you said you could purchase the amp and wood for the box and build it then buy the sub when you've got the dough.
 
Alternate suggestion...

Slice -

Welcome to the forum...

As a suggestion, why don't you copy this unit?

http://www.partsexpress.com/pe/pshowdetl.cfm?&PartNumber=300-739&DID=7

The research has already been done for you, and if you just buy the parts and build the cabinet yourself, you should be able to get pretty close to your $ amount...

Since this is your first project, why not go with something that is a known quantity spec wise? I think you'll be much happier with the result...

Just a suggestion,

Steve

PS - Good Luck!
 
ok i e-mailed Blaupunkt and talked with their tech guys for quite a wile..... they said that the PCwg120 would workd grait in that type of enclosure (2 quibic ft single vent).....they said that they have got many people asking the same Q's as me........
all their sub testing is not done in a car but in and enclosure in the middle of a room.... nothin relly neat.... well i think sence this is my first project and the sub from Blaupunkt is cheap and good sound.....my friend has one....
i will just try this setup for now....
note: i am note looking for the best sound on the market right now.... i am just looking for a place to start for cheap...

well i now need some relly detainled stuff on enclosure design and dementions...


thanks,
keep postin>>>
 
diyAudio Moderator Emeritus
Joined 2001
The Blaupunkt is not really the best choice for a vented box of 2 cubic feet.

Here is a great 10" long stroke woofer from Peerless that is within your price range and almost made to order for such an enclosure. Ten or twelve years ago, this speaker's predecessor was about as good as it got in the subwoofer department at almost any price. Subwoofers have moved up performance wise, but this speaker is still a great value for the money. The only difference between this speaker and it's predecessor is the fact that the new composite cone extends the smooth response up to the 1500 Hz.

Following is the WinISD graph showing it's excellent response in a 2 cu ft box vented to 27 Hz.
 
diyAudio Moderator Emeritus
Joined 2001
Here it is. Really good to 30 Hz.
 

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now you guys say why all the others are good but you are not telling me why blaupunkt is bad!
i relly dont understand why is is so bad i have washed the specs through quite a few programs and they say it is very good....
and so do reviews....
also my friend has one and i think is sounds good......
why are you guys trying to get me to get a different woofer for a first project? i am not looking for perfection...

and if the blaupunkt is so bad why?

thanks,

keep post'n
 
no keep in mind that i dont want the best and i have limited funds.... note i relly dont know what is good or bad all i know is my system is lacking in bass so i want to add a subwoofer....

INSTALLATION CONFIGURATIONS - PCwg120
from blaupunkt
----------------------------------------------------------------------------
Most accurate:
2.0 ft3
Really pleasant deep bass with good tonal quality
-----------------------------------------------------------------------------

all i want is the above nothing more nothing less......
is this good or bad or ok?:confused:
???i dont know what all those picture grapgs mean???
 

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If you've heard your friends and like it then go for it you have nothing to lose. But don't get discouraged when you post here and people recommend different products than you had in mind. Everybody has a "pet" sub or amp that they like and it's the nature of the audio freak to recommend their favorites to everybody who asks.

With regards to the graphs, they're showing the drivers frequency response. You want to avoid a driver/box combo that has lots of peaks and dips in it. A smooth fairly flat line that drops off slowly at a low frequency is what you're generally after. This is quite simplified, but at least now you should know basically what they are.

The plot you posted has a small hump centered around about 60Hz where you're up a little more than a decibel. Looks to be -3dB somewhere between 30 and 40Hz. Which isn't bad at all.
 
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