Speakers (Amp) on High-Level and Subwoofer (Amp) on Low Level?

[ace275]

Piecing together an audio setup. Parts I have acquired are

-JBL 4 Channel Amplifier for Speakers
-300w Under Seat Active Sub
-2x sets of Focal components for doors, front and rear

I plan to connect my speaker outputs on the headunit to the 4ch Amplifier using the High-Level inputs, however the only output on the headunit for the subwoofer is, as usual, the single RCA.

I can see any reason I can't feed my 4 Channel from the High-Level and my Sub from the black low level RCA socket, but just making sure this would be the way to set it up. Should still allow the headunit some level of control of the subwoofer, rather than tying into the speaker outputs

Headunit and both Amps (4ch/mono) support both high and low level

For clarity, I will be sending high-Level to the 4 Channel and Low-Level to the Sub. Neither amp will receive a mix of high or low, just one or the other.

 

[purplea4T]

I take it that's not actually your head unit?
Most I've come across have the 2 outputs for the subwoofer, although this does seem to be a thing for active subs.
If that's your only option, I'd honestly look at changing the head unit to something that will give better control of what you're looking to do.
Also, with 2 sets of components, you'll want to be able to control the higher frequencies as 2 sets of offboard tweeters are probably a bit much.

 

[ace275]

It's not my actual one, but they're both Sony so I'd expect them to be similar at the back. Mine definetly has a single sub output the same as this. In saying that, I would like to change from Wired Android-Auto to Wireless Android-Auto so a headunit change may be on the cards anyway. Though I'm not sure how a headunit could give me much better control however, without having high-level for both speakers and sub?

I could connect the 4x Pre-outs for the speakers to my 4-Channel and the 1x Sub pre-out to the active sub, but I would be losing any possible benefits from using the High-Level outputs from the speaker cables. In theory, using the High-Level would be less open to interference, but it's probably a very slight difference.

The components I have ordered are 2x sets of Focal PS165V1, the crossover units they come with do have adjustable tweeter levels and cut-off frequencies so I can change this as needed

 

[impact]

Why would you not just RCA all inputs?

 

[purplea4T]

Why would you not just RCA all inputs?

That has always been my go to - first install was in 1997, and always used RCAs. My 143db Clio was RCAs to Phoenix Golf PLD1 Line Drivers from a 5V output Kenwood Anniversary back in 2000. Never had a problem with signal noise or interference so I stick to them.

 

[ace275]

I was the same, always used RCAs but basically all the online reading I've been doing has advised it's best practise to use high level where possible, not a single installer or guide had advised to use low level

I does make complete sense with how a signal is transmitted and potentially how influenced it can be by other nearby signals

RCA has always worked fine for me in the past but if high level is truly better, why not utilise it if I can?

There is a good point where RCA low levels could bypass the cheaper on board amp in the headunit, but even then there are alot of claims that these have already run through the amp anyway, and are just stepped down versions of the speaker outputs thus negative any benefit other than RCAs are handy

Real world I'm probably really splitting hairs and either will work well however

 

[ace275]

Just to update, gave up on the absolute minefield of hi/low and just ordered RCAs and I'll stick to what I know