Active Sub with speaker level input

[rubachuk]

Looking to add a little bit of bass using an active underseat sub. I'm using a standard manufacturer headunit which has no RCA outs and I'm on a budget so an upgrade is out of the question at the moment so that leaves me with using the speaker level input on the sub. I know its not ideal and I'm not expecting super quality, just to add a bit of depth to the sound.

I have never wired anything like this up to a speaker level input, so what are the basics? Do I just tag on to the nearest speaker and carry the wire onto the sub which would give you only half the signal if something is in stereo, or do you connect at the headunit to both the left and right channels?

Just some basic info if someone can give me the jist.

[Spudly]

Never done this myself but id guess youd bridge the feeds from both rear channels, i.e. neg from one side and pos from the other, purely a guess but thats how id do it in all fairness, but, having said that, dont the level input plugs have four wires, its been a long time since i looked at one but now i think, you should splice into both pos and neg from both sides and id guess the amp will sort it out internally as thats what the low level input does?

[Hobbit]

There are amps that run using speaker outputs rather than rca's. You would have to take a signal from one of you original speakers. This would mean losing that original speaker though. You cant run both. And yes you would only get left or right signal not stereo.

Other option is to run without an amp using a treble blocker, as a sub is designed to only run low sounds so you need to block everything else out. Again you'd need to sacrifice an original speaker.

Both options arent ideal, especially when you can buy new head units with rca's for not alot of money.

[Hobbit]

Or as Spud says you could try bridging it, you'd still need to run a treble blocker to get the most out the sub though.


Ps you'll probably get the more bass from a set of 6x9's

[rubachuk]

Yeah, maybe. It's the family Galaxy so the headunit would need to be double din which would keep the price up a bit and I'm not really into cutting speaker holes into it. Got to admit though this speaker level input thing is sounding far from a good idea now. Maybe I'll have to suffer with it as it until I can get something double din with RCA outs.

[Hobbit]

Or convert to single din for less than a tenner, then buy a second hand head unit off ebay?