car audio sub conversion [Archive] - Audio & Video Forums


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02-17-2004, 08:37 PM
im planning on taking a 14 inch mtx car subwoofer and building a box to put it in, and then wire it into my centre speaker. i alreadt have a 10 inch out of my receivers line level otuput.

how do i find out what shape and what size of a box sounds good? is there any good site out there?

and is running it through my centre speaker the best? i thought it would be. or would one of the front left, right channels be better?

i dotn have the exact dimensions of the woofer right now but i ll post them in a bit. just any basic help would be apreciated thanks.

This Guy
02-18-2004, 12:27 PM
What you want it to provide the bass to the center channel only? What are you going to drive it with? The best way to use two subs is by using both of them on the sub pre-out on the receiver. Even this way you're probably gonna get muddy bass, not just because its a car sub, but you're running two different subs with different sized drivers and different frequency responses. Download WinISD or "speaker box design program" and plug in the specs. Choose one or the other.


02-18-2004, 04:16 PM
i would wire it into the sub pre out. but this doesnt have a line level input. i dont want to buy a converter thing. im trying to keep it cheap, and the reason i chose the centre is becuase im only going to use the 2 subs on music. like pro logic 2 where my centre receives alot of bass signals. on movies i would probably just keep it off.

what do you guys think about using car subs for subwoofers? i really like the idea, even though i havent heard any, if this works out good i would consider buying more expensive modern amps and clearer more powerful car subs. is there a dis advantage to using car subs?

im using an old mono car amp for the sub. i have no idea on the stats on it. it was my dads old one back when he had it wired into an old truck he had. right now its just sitting in his workshop closet. and i thought why not use it?

02-18-2004, 04:52 PM
i forgot to ask something.

home theatre subs are ported. do i need to put a port on this somehow? i dont think i do, becuase atleast it car audio you dont.

what would be the best way to wire the second sub into the system? off of the line level, im starting to agree now. but how would this work. i need to get from a sub cable to regular speaker wire. is there couplers that do that?

the other sub has line level input / output, as well as high level "speaker wire" input and output.

right now i have a monster sub cable to my sub from my amp. does a sub with out puts like mine only put the output through what it receives. i know it sends a signal out on the line level output but does it send it out through the speaker wire out as well? or do you need to run the input through the speaker wire for the speaker wire output to work?

that sounds really confusing.... i hope someone understands what im trying to ask.

so is there anything out there that transfers sub cable to speaker wire?

This Guy
02-18-2004, 05:13 PM
Car subs are bad for home listening in many ways. First you have to have an amp the can handle the 4 or 2 ohm voice coils in the drivers. Second, many car subs are spec'd with a cars cabin gain in affect, which means the sub won't play as loud in a room. Most of them have resonant frequencies in the mid 30's to lower 40's. A sealed box in a car might have an F3 of 35 hertz, but in a regualr room you can bump that up to around 60 hertz depending on what sub driver you use. And many of these car subs are designed for spl competions, which means they're made to handle a LOT of power, and play one frequency really loud and sound terrible. Now this is a harsh generalization, and there are a few good car subs that may work in home, but it's hard to find which ones because you don't know if their specs are legit or not. What you want to do will make your system sound pretty bad. And if you already have a subwoofer, all the bass that your center channel would have gotten goes to the sub anyway. Set your center as a small. The only way this would work is if you get an amp and hook it up to the center channel pre-outs, buy a crossover to keep a fullrange signal from going to your sub, and THEN you set it as Large. If you want to add another sub, use your subs pre-out and hook up an amp to it which powers your sub. And if I'm hearing you right, no you can't power a sub by using a line output, the line output is just sending a signal to an amp, the amp is what powers a speaker. And the binding posts on the back of your sub are used for using the built in crossover in the sub. I'm having a hard time understanding you, but this whole idea will sound absolutely terrible. Running two different subs with different amplification and everything being different will not sound good at all. Get this idea out of your head.

02-19-2004, 11:58 AM
i dont have any pre-outs on my amp.

if i ran from the centre terminal into the car amp. that pulls out all the bass by its self. it has a built in crossover. and then run from that to my future car sub that im going to build. and from the other terminal out on the car amp to the centre. it has two outs, one that goes to the amp. and one that goes back to the speaker. how would that sound?

This Guy
02-19-2004, 01:19 PM
You can't run speaker wire into a line level input, that's not what its for. Unless you have pre-outs it can't happen. Even if you could somehow run speaker wire into the input, the car amp won't be seeing any low frequency information cause all of that it going to the real sub. The crossover won't help at all. I'm telling you right now, this is a stupid idea and it can't work unless you have pre-outs. Car subs are car subs for a reason, otherwise every speaker company would be using mtx drivers in their subwoofers. I'm serious, THIS WILL NOT WORK, and even if it did, it would sound much worse then what you already have. Didn't read what I said earlier?

02-19-2004, 04:59 PM
yea but im not running speaker wire into a line level. it would be fromt he centre speaker.

all i would be doing is taking the bass signal from my centre and putting it into a much bigger woofer.

This Guy
02-19-2004, 05:08 PM
The center channel isn't getting a bass signal if you set your center as small, all the bass (80 hertz?) and under will go to your sub connected to your subwoofer out. How do you plan on connecting it to the center speaker. If you connect them in parallel the amp will fry. There's no way you can connect another amp to power a center speaker. And as I previously said, the sub will not go very low. It will start dropping off at around 60 hertz cause it doesn't get a cars cabin gain. Look I'm trying to save you some money, if you want to do your little experiment go ahead, but I'm telling you it won't work, or if whatever your trying to do does infact work, it will not sound good.


This Guy
02-19-2004, 05:19 PM
oh wait. I think I know what you're talking about. Running the center speaker outputs from the receiver, to the car amps inputs, then to your center channel. This will work. It won't sound good but it will work. Sorry I had a hard time understanding. But still, I don't reccomend doing it. The crossover in the amp is probably set differently and at a different slope then in your receiver going to your other sub. They will not blend and the car sub will stick out like a sore thumb. The bass will be very sloppy. Try listening to music in stereo where the sound comes out both speakers, it sounds much better. Isn't your current sub good enough? Why don't you save up around $200 and make yourself your own powered sub to replace the one you have now. It will giv you more/better bass then putting another car sub in your system. Plus having two subs improperly placed can lead to cancelations in certain frequencies. And if the subs have similar output, you'll only gain three decibels in volume, except that extra volume sounds very muddy. Build your own home sub and you'll like it so much more.


02-19-2004, 06:02 PM
yea thats what i was going to do. build one and add it in. so i should buy a new woofer huh?

where do i get a good woofer from? "Canada, British Columbia"

ive looked at radio shack but there top of the line woofer is 60 watts rms max. thats not even close to the numbers i want. order off the net or something? and what kind of parts would i need, and where can i get them. could i make a sub with line level inputs and all that? or would it be just a basic high level input sub?

This Guy
02-19-2004, 07:04 PM

They even sell pre-made boxes. Save up some money and get a plate subwoofer amp. Get the 120 or 250 watter. Make a 3 cubic foot sealed box out of 3/4" MDF or just buy one they have for sale.
Here's a good woofer.

get this amp

and here's a box

or you could also just buy one of their pre-made kits. 10" sub with 250 watts in a small enclosure.

Both will sound great, much better then what you have now (Quest sub I believe). If you have a small room the 10" kit would be perfect, plus you can't screw up cause everything you need is in the kit. These two ideas already include an amp to you won't have to use a car amp.

02-19-2004, 10:03 PM
that woofer looks awsome. im going to have to look into that. this site takes orders from canada right? just pay the difference and shipping?

This Guy
02-20-2004, 12:29 PM
Yeh I think you can. Call them about it.