Bias Bass Boost Mod works in G8

[G8Benny]

OK, this is a great post but it got to me too late. I invested in a 1000w sub amp and 2x Alpine 10" subs in a box. I think my system sounds great and I never disconnected or removed the factory subs. Do you think I will notice clearer bass if I use this posts information in reverse and lower the bass? Common sense tells me that the subs are interfering with my system and this will help but again in real life my system sounds awesome, looking too one of you experienced guys to tell me if spending any time on this tomorrow (my day off) would be of any benefit?

[Gavine]

Why not just try it? You can reach the knob without removing anything but the trunk mat. I did this on mine yesterday...it took less than 30 seconds.

[TheTugBoat]

well after reading those last few posts i'm headed out to give it a try

[TheTugBoat]

done and done...the knob isnt quite where the picture describes...its up about 3 inches from that arrow off the trunk deck and feels like a dime. noticeable difference but dont worry you didnt waste your money on aftermarket subs and amp...still needs more juice.

[GXP4RO]

Just picke mine up yesterday and after playing around witht the audio settings i was a littel dsapointed. I'll be sure to try this today after work. Thanks guys!!!

[ProStreet]

Just did this and it sounds better!

[bobyoung]

Originally Posted by vhato

Yea......if it bottoms out now....it will DEFINATELY be worse. This MOD works on most music I listen to, but there are some sounds that just absolutely die in the subs.

There is too much area in the trunk, the subs are not supported by a proper air cushion which prevents excessive cone excursion, they should actually be in sealed or ported boxes. But I will definitely be doing this tomorrow, wondered why there was so little bass with subs in comparison to the rest of the audio. Thanks much for the tip.

[bobyoung]

Originally Posted by G8Benny

OK, this is a great post but it got to me too late. I invested in a 1000w sub amp and 2x Alpine 10" subs in a box. I think my system sounds great and I never disconnected or removed the factory subs. Do you think I will notice clearer bass if I use this posts information in reverse and lower the bass? Common sense tells me that the subs are interfering with my system and this will help but again in real life my system sounds awesome, looking too one of you experienced guys to tell me if spending any time on this tomorrow (my day off) would be of any benefit?

A 1000 watt amp and two 10" subs could definitely cover distortion from the stock subs, can you turn off the new system while it is cranked the way you like it to listen to the stock subs alone? If so I'd do that and see if they are distorting and if they are turn the separate volume control (gain on the sub amp) down, make sure they're in phase also, if not they will cancel each other.

[bobyoung]

I turned the volume control on the subwoofer amp all the way up today and the difference is amazing. I couldn't find it by just slipping my fingers under the side panel though, but taking it all apart and putting it back together again was only a 15 minute job. I did it in a parking lot waiting for my wife, great idea.
I didn't really notice any bottoming out of the subwoofers and I had it really loud for a while playing different kinds of music. I wasn't too thrilled with this system until I did this, huge difference.

[macgto]

Here is another tip to make this sound system even better. I covered the entire underside of the rear deck with Dynamat Extreme. No more rattles, and I was able to turn up the sub amp a little bit more.

mac

[bobyoung]

I couldn't find it either without the panel off so I also removed it, I was careful removing the rear panel, pushed the rubber gasket that goes all around the top of it out of the way and it came right out after the 4 things that hook the netting were unscrewed. The volume cointrol is in a wierd place, it's up and in the bottom of the unit right in the middle and if you imagine it being the front of a radio upside dwon just turn it the way you would turn any knob to increase volume. Clockwise.

Originally Posted by Silvereagle

One word, be careful when removing the trunk panel where the latch is....it is clipped on so you pop it up vertically.......not back towards the wall of the rear seats. Otherwise you might destroy your panel ike i did today Part # 92213099 ...cost is $40.00 from dealer.......so I bled one for you guys

Pics here of what I mean.

[romeyjdogg]

Has anybody tried to find the clipping point of the subs or the headunit? Maybe the gain was set at the factory setting for a reason? I haven't picked my car up yet (Tomorrow!), but I would imagine the speakers will go into clipping if you're turning the gain up higher than 80%.

[Mav]

I didnt have to rip apart too much, I just used a hand held mirror and was able to get in their without too much ripping.

[macgto]

Originally Posted by theGeneral

I didnt have to rip apart too much, I just used a hand held mirror and was able to get in their without too much ripping.

Having had expirience with my GTO, I was able to adjust mine without issue.
Remove the spare tire cover. Slide your hand, palm side up, under the left side panel, ahead of the battery. The amp is located forward of the battery, with the gain control knob facing bottom. The knob is about the size of a dime.
Best to have the stereo on while making the adjustment so you know which way to turn it. Using your middle finger and your index finger, rotate the knob. By default, it should be set at 50%. There is a detent at that position that you can feel. Adjust up or down to your liking. I had mine set slightly above the 50% mark at first. Then, after applying the Dynamat to the underside of the deck, to kill the rattling, I was able to adjust up to somewhere around 75%. Makes a big difference in the low end.
Bass control on the head unit set to +4, treble at +6, no EQ, loudness on.
At these settings, can pretty much run the volume up to 20 on newer, more bass intensive cds or mp3s, 25 on older cds.

mac

[T.Rex]

Originally Posted by macgto

Best to have the stereo on while making the adjustment so you know which way to turn it.

That is a very good tip. I was trying to follow the clock-wise, counter-clockwise advice and went 100% the wrong way the first time. Easier to just have the stereo on and you can easily tell which way's up!

[sykotek-g8]

Thank you Thank you Thank you Thank you Thank you Thank you.

I just went outside and played around with this. Easy to get to, just had to lift out the spare tire (I mean "puncture repair compressor") cover and gently lift up on the side panel covering the battery and amp.

After some messing around, I ended up with the amp cranked to 100%, the bass set at 0 and the treble at +3 or +4 depending on the music. I cranked out some Atreyu, NIN, Five Finger Death Punch, and All That Remains, everything sounds incredible. I had a pair of 8" SAS tubes with punch 8's and a 200W punch amp, I'm going to hold off on installing it for now, this rocks as is.

I also flipped through the hip hop stations on my sirius radio, sounds good as well, but the bass lines in that music did cause some distortion at higher volimes.

Everything else could be cranked to 40 to 45 and it was crystal clear and f-ing LOUD. Having the bass down on the head unit and cranked on the amp really clears up all of the distortion in the stock interior speakers.

This is officially my new favorite web site. Picked up my 2008 GT Friday 10/24.

[TheTugBoat]

yeah i just go my rear deck dynomat'd today, sounds alot better no more ratters from there...just gotta fix the rear doors now, might try turning the gain all the way up and the bass in the eq down like syko, should take care of it for now

[T.Rex]

Originally Posted by sykotek-g8

This is officially my new favorite web site. Picked up my 2008 GT Friday 10/24.

This little piece of information was pretty much when I fell in love with this forum also! I took delivery of an '09 GT on 9/24 and stayed up until about 3AM reading this forum that night.

Congratulations on the new car!

[therapture]

Originally Posted by bobyoung

There is too much area in the trunk, the subs are not supported by a proper air cushion which prevents excessive cone excursion, they should actually be in sealed or ported boxes. But I will definitely be doing this tomorrow, wondered why there was so little bass with subs in comparison to the rest of the audio. Thanks much for the tip.

Given that the trunk is basically an infinite baffle (compared to a 2 cubic foot box) then by hunting down some "free air" subs that are MADE for that type of application, would probably increase output quite a bit.

When I get my liquid red GT on Feb. 1st, I will be doing something to the subs, how far I go depends on what I can make happen by decreasing the bass gains at the deck and increasing the sub amp gains....

..I imagine in the end though, I will probably be adding a modest dedicated amp and a single solid 12" firing into the cabin.

[Chief]

Interesting thread here.

I guess someone at the factory had already set mine up as I have almost too much bass and I haven't even touched the amp yet. I set up the EQ to the Jazz setting and actually have a little more bass than I like. I haven't checked it to see where it's at but may check it this weekend. If anything, I might actually turn it down some.

As for rattles, does any one else have a rattle in the overhead pannel with the sunroof dial? I did and so added a couple of small felt bumpers under the pannel which solved the rattle. No rattles from the back pannel but I do hear some from the truck when standing outside. Also I can feel the bass throughout the car. All you have to do is touch any part of the interior and you can feel it.

This is what makes me think mine is already turned up.