Sub amp inputs

[ReekieVR 0]

If i have a sub amp which has two types of input:

 

a line-in and a speaker feed in. Will there be any downsides using the speaker-in method as opposed to the line-in method ?

 

I ask because if i use the speaker feed method, i only have to run 1 cable from the boot to the battery and thats me ( the amp switches on automatically when a current is detected on the speaker in cable - which already exists in the boot ). If i use the proper line-in method, i need to run another 3 cables from the head unit to the amp ( remote on & l/r line out ).

 

Oh the speaker wire to the boot is standard. If i used the speaker-in method would i need to upgrade the cable even though its not driving a speaker?

[bristolbaron 10]

im pretty sure that speaker feed in is only used if you have no RCA output on your headunit.

i would imagine the sound quality will be far worse using rear speaker cable.

[mrbeige 0]

As the baron says, sound quality is worse. Run the RCA's, its not that big a job. Just take the seats out and the centre console and feed the cable up the middle and under the carpet.

[gaz the geezer 0]

If i used the speaker-in method would i need to upgrade the cable even though its not driving a speaker?

 

using the line in method is better, if you use good quality cable it offers more sheilding from other electrical influences and the amp trigger wire is usually part of the cable assembly - dont be a lazy get, you know it makes sense :lol:

[Kevin Bacon 5]

Speaker level preamps are very crude and not ideal, but they're convenient.

 

The number one problem with speaker level inputs is distortion. Your headunit will see a very high impeadance and any distortion present in your headunit's amplifier will be amplified along with the music too. Typical distortion of a H/U amp is 10% at 1khz @ 80-100% volume, compared with 0.1% from an RCA preamp at max chat. You will hear that 10% distortion big time if you use the speaker level inputs!

 

Ideally you want to switch off the headunit's internal amp completely if possible, and just use the RCAs ("internal Audio" setting on Alpines).

 

So running more cables it is you for you :-)

[ReekieVR 0]

Thanks for the help peeps. This truely is a great forum.

 

I presumed that line-in was the quality route, but didnt know why. Thanks for explaining this stuff.

 

Will scoot off and get proper wiring kit and spanners.....