Using gain setting to equalize car front speakers and subwoofer

[gabrielb]

Is it possible to use the gain on the AMP to equalize the volume between the front speaks and the sub?
My setup is a 2.1 with 2-way front speakers (Infinity 603CF) connected to Pioneer GM-8704.
I plan to bridge the second pair of AMP output to power a passive sub, but I'm not sure if it is possible to match volume.

One option is to find the correct gain setting on both channels (front and sub) independently and then run them both and decrease the gain on the louder channel.
Is this a valid option?
My understanding is that gain matching between the car radios and the AMP aims to get the AMP to work on its max power (and that exceeding it will lead to clipping) and that having too low gain means I won't get the full power from the AMP.
The AMP has plenty of power (100W RMS per channel on the front and 300 on the bridged SUB) so even if I lower the gain by 50% I will still get 50W per front speaker.

Another option is running both channels at full gain adding a passive line control like PAC LC-1 (https://www.audiosciencereview.com/...pac-lc-1-passive-volume-control-review.34135/) between the louder channel and the AMP and use it to lower the volume.

Which option should I choose?

 

[DVDdoug]

My understanding is that gain matching between the car radios and the AMP aims to get the AMP to work on its max power (and that exceeding it will lead to clipping) and that having too low gain means I won't get the full power from the AMP.

In the real world, one amplifier is going to clip before the other. Bass usually requires a LOT more power so if you have a crossover (or filter) blocking bass the the front amp, bass will probably clip first, even with 300W. But of course, that depends on the music and tone controls/EQ. The sensitivity of the speakers also matters. (The sub may need more power to be equally loud... Or maybe less power.)

Ideally, it will go loud enough with neither amp clipping.

The second best thing would be for one of them to clip first half the time and the other one to clip half of the time, depending on the program material and EQ settings.

My understanding is that gain matching between the car radios and the AMP aims to get the AMP to work on its max power (and that exceeding it will lead to clipping) and that having too low gain means I won't get the full power from the AMP.

Usually you want plenty of gain so can get full loudness with all program material and all sources (the radio may be louder than Bluetooth or CD, etc.). Typically you should be able to push it into clipping if you wanted to. But you don't want so much gain so that it clips with the volume at 25%, etc.

Another option is running both channels at full gain adding a passive line control

I don't think you need that. I would only do that if you can't get it set-up to your satisfaction with the existing gain controls.

 

[gabrielb]

In the real world, one amplifier is going to clip before the other. Bass usually requires a LOT more power so if you have a crossover (or filter) blocking bass the the front amp, bass will probably clip first, even with 300W. But of course, that depends on the music and tone controls/EQ. The sensitivity of the speakers also matters. (The sub may need more power to be equally loud... Or maybe less power.)

Ideally, it will go loud enough with neither amp clipping.

The second best thing would be for one of them to clip first half the time and the other one to clip half of the time, depending on the program material and EQ settings.


Usually you want plenty of gain so can get full loudness with all program material and all sources (the radio may be louder than Bluetooth or CD, etc.). Typically you should be able to push it into clipping if you wanted to. But you don't want so much gain so that it clips with the volume at 25%, etc.


I don't think you need that. I would only do that if you can't get it set-up to your satisfaction with the existing gain controls.

Thanks for the detailed reply.
The AMP has crossover setting for the front and the back channels.
At the moment I'm running the front speakers at 25% power with full frequency spectrum (they go down to 45HZ)
With active XO the front speakers will have plenty of power after filtering out the low frequencies (the infinity kappa 603cf published sensitivity is 93 and the AMP supplies 100W RMS per-speaker).

I plan to get the infinity primus 1270B SUB which is rated for 300W RMS@4ohm (91 senativity) matching the bridged second channel on the AMP (300W RMS@4ohm).

Seems like I should run the SUB channel at full gain and reduce gain setting on the front channel to match volume