Quick car audio question

phil675 · 27 Jun 2012 at 15:30

Hi,

Thinking about doing an amp/speaker/sub upgrade on my sisters recently purchased Mini. Do 4 channel amps generally allow you to change the gain on both channels independently?

For example, high gain on the component speakers stereo channel and low/medium gain on the subwoofers mono channel?

Thanks

cwhitehead · 27 Jun 2012 at 15:38

Ussually yes, the have a HPF and LPF filters If running a sub would need to be bridged ussually though.

phil675 · 27 Jun 2012 at 15:38

Actually I've just thought, can you even have 2x stereo and 1x mono? Do they all have to be the same? i.e. 4x stereo or 2x mono?

cwhitehead · 27 Jun 2012 at 15:45

4 channel

2 channels front speakers HPF

3rd channel (3/4 channels) bridged LPF

That said its better to run a front speaker amp and a seperate mono dedicated amp.

phil675 · 27 Jun 2012 at 15:47

Hmm ok, 2 amps might be better I suppose. I think I'll struggle to find a compact subwoofer though

cwhitehead · 27 Jun 2012 at 15:53

JL do a great range of "slim" subs

The mini's boot is rediculously small though if you still want use of it.

phil675 · 27 Jun 2012 at 16:49

I was thinking maybe an under-seat one might be an option but they look a bit rubbish.

cwhitehead · 27 Jun 2012 at 16:58

An under seat would be rubbish as you say but the airbag light cabling is under there too and does cause problems later on in life as it wears without a sub under it. Just a heads u p.

Frozennova · 27 Jun 2012 at 17:07

You could always get a 5 channel amp? The 5th channel is a dedicated sub channel.

Kei · 27 Jun 2012 at 18:18

Just remember that the "gain" pot on the amp is not a volume control. If the headunit outputs 2V don't set the gain to a voltage any lower than 2V. If you set it at say 1V it will clip the signal when the headunit is turned up. Minimum gain will be something like 4V and max is usually 0.1V.

phil675 · 28 Jun 2012 at 13:04

Aye, I was just thinking that the fronts and backs might be wildly different but I think the fronts and sub will both be around 100W RMS anyways.

Another quick one

How does splitting an RCA cable in to two work? Will I have 2 lefts on one side of the splitter and 2 rights on the other side?

Frozennova · 28 Jun 2012 at 13:09

phil675 said:
Aye, I was just thinking that the fronts and backs might be wildly different but I think the fronts and sub will both be around 100W RMS anyways.

Another quick one How does splitting an RCA cable in to two work? Will I have 2 lefts on one side of the splitter and 2 rights on the other side?

RCA cables are a stereo cable. If your replacing the head unit you should have a front, rear and sub pre out so no need to split it.

phil675 · 28 Jun 2012 at 13:16

ManLoveRulesOK said:
RCA cables are a stereo cable. If your replacing the head unit you should have a front, rear and sub pre out so no need to split it.

I have no idea about the back of the head unit yet but I'm assuming it only has 1 line out, so I will need a splitter of some sort for the 2 amps? :confused:

It's a cheap looking Sendai one that probably won't get replaced and if it does it won't be anything decent.

Frozennova · 28 Jun 2012 at 13:19

You'll be fine but will need to split it into three as a 4 channel amp needs a separate input for front and rear.

phil675 · 28 Jun 2012 at 13:21

Ok, I'm going for a 2ch and a mono now. If I can find one with a passthrough that would be a bonus! Serious ebay trawling is required