Head unit don't distort at max volume either through RCA's or through amps

[jcthelight1976]

Hi everyone I have a Sony ax4000 and I use the SMD dd1 tool to check for distortion and I don't have any Distortion at max volume of 50 through the RCA's or through the amps 

And when testing for distortion at the RCA output of the head unit for the subwoofer if I leave the subwoofer level down one notch below halfway in the head unit I don't get no Distortion at max volume so should I leave it that way and then set my gains on my amps I have a four channel amp and a monoblock also the manual doesn't say what test tone you should use for the subwoofer output on the head unit

[Jessica]

I assume you have all EQ and bass boost and other options set to off on the headunit? 

 

Since you are showing no distortion you should be good to go to adjust gains. If you have a remote gain knob for your subs you can use a 40hz test tone to set the amp gain with the presumed gain knob at max (testing the amp output). I personally use a -10db tone for subs, but -5 or -7.5 are fine too. Its going to come down to the type of music you are going to play. Going with -10db will give you more overlap and more risk of clipping/distortion. 
 

That being said, testing with different levels is fairly easy until you find what works for you. Side note, for mids/highs i use a -5db tone at 1khz at the amp output. 

 

hope this helps. feel free to ask if ive made anything unclear