JOSPRE

Had a 6-channel Sony Amp XM-GS6DSP and two Sony 10" subs from my prior truck installed into a new Fox Box in my STX Screw running off the stock Sync3 head unit. The audio shop used a line out converter from the rear speaker channel to run RCAs to the amp. The subs sound great except they stop playing above 15 volume (half way). If we bump it to 16, 17, 18, etc. they cut out intermittently. If we bump it to 20, they cut out complete. The amp is not going into protect mode (or at least the light is not indicating that) and the car audio shop said we are not losing voltage. I'm concerned it's an issue with the signal coming from the head unit. Is this a known issue with the Sync3 system or did we do something wrong?

Kkline

JOSPRE

Thanks for the quick reply. We did each of those things today back at the car audio shop. No material voltage drop at the battery or the amp at high volumes. I would hope it's not the battery since the truck has 200 miles on it. Power wire and ground wire seem good. It's like the amp is struggling at higher volumes so it just gives up and stops altogether.. but I'm surprised the protection light isn't coming on. Never seen it before and did not have this issue with it hooked up to the same speakers in the prior vehicle, however, it was being pushed by an aftermarket head unit; not a stock head unit. That's why I was wondering if it was the Sync3 system.

dhmcfadin

Sounds like your subwoofers are wired out of phase. Can you describe the cutting out in more detail?

Grab a multi meter and first check the impedance at the speaker terminal of the enclosure. Then grab a 9 volt battery. Hook positive to positive and negative to negative. Check to make sure both woofers move outward together. If they move independently, they are wired out of phase.

Next, you stated you used the rear speakers for signal. On the newer trucks, the rear speakers have a 70hz highpass crossover built in along with bass roll off to protect the oem speakers. Depending on how you have your crossover setup on your amp, you could literally be cutting your output signal down to nothing with those combination of factors. Again, a multi meter can help you. Play pink noise, start turning the volume up and measure the output voltage of the amps speaker terminals. It should be a linear increase in voltage as the volume goes up with no dips.

HushCarAudio

Check to see if the amp is getting super hot too.

Bjude1

Is the sound really loud before it cuts out? Maybe the LOC needs to be turned down. Another thought would be that when the subs were put into the new enclosure they were wired up at 1 ohm and that amp wont do that.

supercanadian

How is the blending of sound? are the door speakers scream at 15 level on the headunit?

dhmcfadin

This is a definite possibility. You will want to check the gain on your LOC. You could be clipping the inputs of your amp. But I honestly think there is a polarity or wiring issue.