I have a 2009 Hummer H3 Lux w/ Monsoon system and recently purchased a new head unit (Sony WX-900BT) that I received from Crutchfield. I also bought a wire harness (Metra GMOS-04) to use with the radio. I installed it and correctly wired it up. The sound quality good with no interference and distortion, except the subwoofer sounds off. The stock head unit sounded alot better than the new head unit compared to lows. Some bass seems to be missing and is a lot more muddy than the stock system. It seems less prominent and quiet, and a little strange. I can't really describe it too well other than that it sounds off and worse that the stock head unit Is there some possible fix to this? I'm running this system stock through the wire harness and not the pre amp outs. I will replace the component door speakers in the future. I would just like to see if I can fix the subwoofer issue without buying a system and having to wire a box in the back of my trunk.

 

Make sure you don't have a crossover set on the Sony. Disable any low pass or high pass crossover.

 

I have already disabled the crossovers and experimented with various eq settings. I can't find any issues with the settings I have changed in the head unit, as they don't seem to make much of a difference. I have also make sure that the Mega Bass feature was off, as enabling it might boost low frequency's or change crossovers (not too sure). There is also a strange setting regarding sending subwoofer frequencies to the rear component speakers. Is the sub connected to a wire that the aftermarket wire harness does not fully support? I'm not too sure how the subwoofer even connected to the stereo system. Would there be a way to hook the subwoofer up to the sub out on the head unit?

 

The GM0S4 will not push high level signals to the monsoon amp. There should be a procedure where you have to tune the volume level of the new head unit and gmos4 to pass a low level signal to the monsoon amp.

 

There was a **** on the wire harness that can be turned using a screwdriver. I used it to adjust the volume of the chime and warning sounds, but I do recall that it can be used to adjust the gain. I will try to adjust the gain, as I noticed that the new head unit it is less loud compared to the stock. The sound begins to distort when I try to reach higher volumes on the new head unit as well. Would this change after the gain adjustment?

I also have another question (sorry). How are the component speakers powered? Do they run off the amp located next to the subwoofer, or are they powered off the harness? My Sony can output 55x4 RMS, and I was wondering if that was being utilized through the harness, or if that is only available through the pre-amp outs. If I am able to fix this issue with the subwoofer, I would possibly consider replacing it with a more capable sub and possibly amp (would have to consider the power and space though, as I recall there not being an incredible amount of depth in the area and as well as the 8-gague wire (I think) carrying the power.

 

Update: Thank you! That seemed to answer most of my questions and fix my disappointment surrounding the new head unit! Now I don't feel the need to buy a separate sub and amp box for my trunk.

Would buying a sub of similar specs also increase bass quality and loudness? Something that could fit in the space of the factory sub without adding or changing the current amplifier? I was originally looking at high end Sundown audio or Skar subwoofers until I really understood the size of the magnets they had (way too deep for the factory box) and the power requirements. I was thinking of something that would truly be an improvement without changing anything but the sub (I would love to be able to purchase a JL audio Stealth Box, but they seem to expensive for me).

And I'm sorry that this is in the general forum, it should have been in the A/V forum. (I'm new to this)

 

Would there also be a way to use my head unit to power all of my component speakers and tweeters? If so, could I then get a monoblock amp and dedicate all the power to the subwoofer (if I replace the factory one). That way I could get a 300-400 watt amp for the sub only, and use the built in one in the head unit, witch could allow me to get a bigger subwoofer without rewiring with better wires (if I don't have to do that to allow the head unit to power the speakers). My main goal is to get a better sub without having to have a box in my trunk. I most likely will upgrade the door speakers later on, but I heard that you can pretty much just splice them on without any extra wiring. If you have any recommendations or suggestions on how this can be done, let me know. Thanks in advance! (if anyone wants to help)