Bass Mod for Factory Amp

[SRG963]

The sub-amp is in the trunk next to the battery.

Remove all the covers, slide fingers below amp and feel for gain control and give it a turn.

http://members.cox.net/sandifer4/g8bass1.jpg
http://members.cox.net/sandifer4/g8bass2.jpg
Info provided by vhato, thanks :)

[Chewy]

Bias? You mean gain right?

I swear I corrected this mistake on board several months ago...

[SRG963]

Biasing in electronics is the method of establishing predetermined voltages and/or currents at various points of a circuit to set an appropriate operating point.

The operating point of a device, also known as bias point or quiescent point (or simply Q-point), is the point on the output characteristics that shows the DC collector-emitter voltage (Vce) and the collector current (Ic) with no input signal applied. The term is normally used in connection with devices such as transistors.


Probably has nothing to do with it, but other pep's called it that, way before I. lol

[Chewy]

I disrupt the flow when it's not right... That is the gain control...

From wiki...

In electronics (http://en.wikipedia.org/wiki/Electronics), gain is a measure of the ability of a circuit (http://en.wikipedia.org/wiki/Electrical_network) (often an amplifier (http://en.wikipedia.org/wiki/Amplifier)) to increase the power (http://en.wikipedia.org/wiki/Power_%28physics%29) or amplitude (http://en.wikipedia.org/wiki/Amplitude) of a signal (http://en.wikipedia.org/wiki/Signal_%28electrical_engineering%29). It is usually defined as the mean ratio (http://en.wikipedia.org/wiki/Ratio) of the signal output (http://en.wikipedia.org/wiki/Signalling_%28telecommunication%29) of a system to the signal input (http://en.wikipedia.org/wiki/Signalling_%28telecommunication%29) of the same system. It may also be defined as the decimal logarithm (http://en.wikipedia.org/wiki/Logarithm) of the same ratio.

chris

[SRG963]

I disrupt the flow when it's not right... That is the gain control...

From wiki...

In electronics (http://en.wikipedia.org/wiki/Electronics), gain is a measure of the ability of a circuit (http://en.wikipedia.org/wiki/Electrical_network) (often an amplifier (http://en.wikipedia.org/wiki/Amplifier)) to increase the power (http://en.wikipedia.org/wiki/Power_%28physics%29) or amplitude (http://en.wikipedia.org/wiki/Amplitude) of a signal (http://en.wikipedia.org/wiki/Signal_%28electrical_engineering%29). It is usually defined as the mean ratio (http://en.wikipedia.org/wiki/Ratio) of the signal output (http://en.wikipedia.org/wiki/Signalling_%28telecommunication%29) of a system to the signal input (http://en.wikipedia.org/wiki/Signalling_%28telecommunication%29) of the same system. It may also be defined as the decimal logarithm (http://en.wikipedia.org/wiki/Logarithm) of the same ratio.

chris


Dude, you don't need to explain that for my info, I've been installing car audio for over 15 years :)


But good info nevertheless

[Chewy]

I didn't... I did it for the others out there... lol

Sa'll good!

I stuck the thread... It's good info.

[g8sponge]

Another great free mod. Like Xmas.

[Bretz56]

Thanks!!! This really woke it up. And turning off the eq is even better yet. :woohoo:

[deputycrawford]

I found out that after I turned up the amp. I also adjusted the eq by turning off the preset settings and adjusting the manual bass around 4 + and the treble around 5 -. Then I turn the preset eq on to the rock setting and it makes a big difference. You have to keep turning off the preset stuff and adjusting the manual settings. When I was finished, it sounded soo much better. It got me to hold off on modding my stereo.

[Wag 42]

I thought the bass didn't sound too bad in my car, some songs actually had a good thump to them. I thought I would try this yesterday. Once I attempted to adjust it, I figured out it was already all the way up. Oh well...

[Virus]

Thank you for the write up, unfortunately this doesn't help the horrible sound of this factory system. It is by far the worst OEM setup I have ever listened too. My wife's Nissan Quest sounds better :-(

[syP]

my old old old 2000 Grand Prix GT with "non bose" stereo hit MUCH harder.

kinda sad.

[Virus]

my old old old 2000 Grand Prix GT with "non bose" stereo hit MUCH harder.

kinda sad.

They bottom out and distort very easily. I'm extremely disappointed.

[JoeSyko]

Thank you for the write up, unfortunately this doesn't help the horrible sound of this factory system. It is by far the worst OEM setup I have ever listened too. My wife's Nissan Quest sounds better :-(


my old old old 2000 Grand Prix GT with "non bose" stereo hit MUCH harder.

kinda sad.

Really? I think the factory system cranks. In fact, my 14 year old son likes it so much, he's constantly asking if he can have the keys so he can go listen to his MP3 player in the car. He says he loves how the bass sounds.

[grt08g8]

To all of you audio wizards or anyone that has pulled out the factory stereo, are there any unused rca's on the factory stereo, i would like to maintain factory stereo and just add some big bump to it

[GT-610]

just stop your whining fellas and put an amp in!
I did and theres no looking back!

[Virus]

How did you hook everything up to the stock head unit? 3Sixty?

[R.Penguin]

Thank you for the write up, unfortunately this doesn't help the horrible sound of this factory system. It is by far the worst OEM setup I have ever listened too. My wife's Nissan Quest sounds better :-(
Audio sound interpretation is an individual thing. And you are very individual.

Me, I'm old, feeble and never turn the system on. My favorite station is the one the exhaust system plays 24/7.

[R.Penguin]

The sub-amp is in the trunk next to the battery.

Remove all the covers, slide fingers below amp and feel for gain control and give it a turn.

http://members.cox.net/sandifer4/g8bass1.jpg
http://members.cox.net/sandifer4/g8bass2.jpg
Info provided by vhato, thanks :)
Thanks Mang. I sorta forgot I don't hear so good since my brain exploded awhile back.

Too bad. I have a monster collection of great CD's. Uh, EH? What? :p

[TaskForce]

Great free mod, made a big difference in my system - I think mine was set at about 25%, now it is about 80%.

[flensr]

FYI, you can do this without taking the covers off as long as your wrists aren't too fat. I just took out the floor cover and was able to loosen the base of the side cover just enough to get my hand inside there. The adjustment knob is the only thing there, and it even has a little detent at the factory preset setting so you don't need to guess where center is.

I will admit I adjusted it without taking off the side cover because I couldn't figure out how to get the side cover off without taking off the front cover, and couldn't figure out how to remove the front cover without putting down the center armrest, and couldn't do that without taking out my newly-installed child carseat, so... :)

If anyone knows the easy way to remove that side panel, I'm interested...

[RobA300]

I did this a couple days ago and it rounded out the sound nicely. I am not a fan of booming bass, but it needs to be there for the right sound and this gives you just enough.

[SpeedRacerX]

FYI, you can do this without taking the covers off as long as your wrists aren't too fat. I just took out the floor cover and was able to loosen the base of the side cover just enough to get my hand inside there. The adjustment knob is the only thing there, and it even has a little detent at the factory preset setting so you don't need to guess where center is.

I will admit I adjusted it without taking off the side cover because I couldn't figure out how to get the side cover off without taking off the front cover, and couldn't figure out how to remove the front cover without putting down the center armrest, and couldn't do that without taking out my newly-installed child carseat, so... :)

If anyone knows the easy way to remove that side panel, I'm interested...

Great tip! Done. Easy. I was able to fit my hand in...


I did this a couple days ago and it rounded out the sound nicely. I am not a fan of booming bass, but it needs to be there for the right sound and this gives you just enough.

I agree with you. I'd rather have the amp all the way up and adjust down from the EQ inside the vehicle than not have enough up front to really fill it out.

[Panzer Leader]

OK will do it tomorrow. My biggest concern is following, Tweeters are weak, and to be honest, it sounds like no sound from the door speakers at all. Someone suggested the Infiniti 2 way speakers in the doors. If along with adjusting the sub amp as described here hoefully will improve overall sound quality w/o bankrupting me. Anyone with thoughts on this just jump in. BTW is the sub amp the only amp in the car? Are the other amps adjustable? How difficult to get to them if they do exist?

[SpeedRacerX]

OK will do it tomorrow. My biggest concern is following, Tweeters are weak, and to be honest, it sounds like no sound from the door speakers at all. Someone suggested the Infiniti 2 way speakers in the doors. If along with adjusting the sub amp as described here hoefully will improve overall sound quality w/o bankrupting me. Anyone with thoughts on this just jump in. BTW is the sub amp the only amp in the car? Are the other amps adjustable? How difficult to get to them if they do exist?

Good question on the Amps. Heck, I can't even find where all 11 of my speakers are. And where are the subs?!?!
:hmm:

[Panzer Leader]

Good question on the Amps. Heck, I can't even find where all 11 of my speakers are. And where are the subs?!?!
:hmm:

Factory Speaker System 11 Total Speakersw 2 dash tweeters, 1 center dash speaker, 2 front door speakers with paper cones, 2 rear door speakers with tweeters (Counts as 4 speakers) and 2- 8" subwoofers. TOTAL 11

Major question is how to control that center speaker?

[MoonPie]

My favorite station is the one the exhaust system plays 24/7.

Fo Sho!
Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0) BlackBerry8310/4.2.2 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/102

[Panzer Leader]

Thats because Penquins love to keep their feet warm by the exhaust.

[SpeedRacerX]

Factory Speaker System 11 Total Speakersw 2 dash tweeters, 1 center dash speaker, 2 front door speakers with paper cones, 2 rear door speakers with tweeters (Counts as 4 speakers) and 2- 8" subwoofers. TOTAL 11

Major question is how to control that center speaker?

Thanks. "Paper cones?" Yikes. I'll be fracturing them soon...

[gearhead455]

I cant feel any screw, just the mounting screw,my fingers are short stubs though.

:(

[gearhead455]

Bass mod complete. :)

[Gris]

I also did it by slipping my hand under the bottom of the cover. I found turning the control all the way up to max. resulted in too much distortion. I backed it off a nudge (about 5-10 degrees) and it's just fine now.

[speed_junkie]

I must have turned the knob seven hundred rotations before I realized it was the
mounting screw LOL...

[Punisher]

I did mine too....I read that you had to turn it clockwise but I noticed that would reduce the bass...so I tried counter clockwise and bam....you can really hear the difference now...Great Thread!

[newman27]

At first I thought this was a snipe hunt - I couldn't find that darn control. I finally found it. The control is a round, flat dial that sticks out maybe 1/4". If you have your hands on anything with a point on the end you are touching a mounting screw or bolt end. Turn it counter-clockwise to increase bass. As mentioned there is a centering point that catches slightly so you know where the mid-point is. I put the radio on XM 80 (techno music - guaranteed steady stream of bass) to better hear the adjustment.

[scorpio ps]

Tried looking for the amp. No luck. Could mine be somewhere else. Two box looking things on the underneath of the back deck. 2009.5 G8 GXP.

[SpeedRacerX]

Tried looking for the amp. No luck. Could mine be somewhere else. Two box looking things on the underneath of the back deck. 2009.5 G8 GXP.

Standing at your rear bumper, looking into your open trunk. There's a compartment to the left side that opens up to reveal the battery. Just past that (a few inches forward), if you can squeeze your hand behind the black side trunk liner is a medium-sized black box which is the Amp. Underneath of it, sort of bottom right of the Amp, if I remember correctly (it's been a long time since I did this) is a little knob that you can turn to crank it up or down. It has a "bump" at its middle setting that you will feel when turning. If you don't know which way to turn it (I think it's clockwise) just keep your stereo on with a good bass song and you'll hear it "thump" more or less depending on how you turn the knob - and then you'll know.

Hope that helps...

[superspud]

I think it's clockwise, not counter. Though it only nets a slight improvement. Of course I was spoiled with a JBL 300x4 amp in my GP with JBL XR component speakers.

[bobyoung]

Biasing in electronics is the method of establishing predetermined voltages and/or currents at various points of a circuit to set an appropriate operating point.

The operating point of a device, also known as bias point or quiescent point (or simply Q-point), is the point on the output characteristics that shows the DC collector-emitter voltage (Vce) and the collector current (Ic) with no input signal applied. The term is normally used in connection with devices such as transistors.


Probably has nothing to do with it, but other pep's called it that, way before I. lol

Tubes also need to be biased, controls the amount of plate current. I have to set the bias voltage on my ham transmitter every time I use it and my bass amps every several months.
The control on the power amp (sub amp) in the trunk is called a gain control which is the same as a volume control. Turn it clockwise to increase it as you do with almost all controls. I have mine up all the way.

[bobyoung]

At first I thought this was a snipe hunt - I couldn't find that darn control. I finally found it. The control is a round, flat dial that sticks out maybe 1/4". If you have your hands on anything with a point on the end you are touching a mounting screw or bolt end. Turn it counter-clockwise to increase bass. As mentioned there is a centering point that catches slightly so you know where the mid-point is. I put the radio on XM 80 (techno music - guaranteed steady stream of bass) to better hear the adjustment.

Counter-clockwise only because it's upside down, you're really turning your fingers and hand clockwise to avoid confusion. counter clockwise from eye level but in reality clockwise like any other control, just remember it's upside down with the control facing the bottom of the car.

[bobyoung]

Thanks!!! This really woke it up. And turning off the eq is even better yet. :woohoo:

I get the most bass by far by turning off the EQ and setting the manual bass and treble controls to max and fading the sound to the rear by +2 which lowers the volume in the front of the car accentuating the subs. I think this system sounds great I've been playing bass for years and love bass and I get enough from this system stock.

[WickedMom]

This just goes to show that eventually GM listens to us!


#09-08-44-014: Information on Increasing/Decreasing Bass Level and Range of Bass Gain Control Adjustment for Subwoofers - (Aug 7, 2009)

Subject: Information on Increasing / Decreasing Bass Level and Range of Bass Gain Control Adjustment for Subwoofers

Models: 2008-2009 Pontiac G8

Attention: The information in this bulletin may be shared with your customer, and a copy of this bulletin may be given to the customer. No attempt should be made on the repairing dealers' part to submit for, or claim warranty for this non-recommended, customer completed adjustment.
Pontiac G8 Entertainment System Overview

Customers of the Pontiac G8 are provided a broad range of adjustments available through the radio that allow the sound quality to be tailored to the listener's preference. The range of bass control adjustment has been pre-set at the factory taking into consideration the vehicle acoustics, the quality and clarity of the delivered sound and the physical limits of the audio components.
Subwoofer System Operation

The G8 is equipped with two 8" Subwoofers in the rear shelf of the vehicle. These speakers are powered by a separate amplifier. In addition to the radio bass control, it is possible to adjust the output of the subwoofers utilizing a manual control on the amplifier body. This gain control may be used to boost or attenuate the bass frequencies proportionately and relative to the radio bass setting. Adjusting the amplifier gain will increase or decrease the overall range of adjustment offered by the radio's bass control.

The procedure below details the amplifier adjustment process for the customer. GM does not endorse nor encourage additional adjustment of the amplifier gain control beyond the factory settings, however, increasing the gain control setting WILL NOT cause undue stress or damage to the audio components. Adjusting the subwoofer gain upward may result in high volume speaker rattle or buzz, as well as possible sympathetic noise (vibration) from interior trim panels. Objectionable audible vibrations and higher volume speaker distortion as a result of this adjustment WILL NOT be covered under warranty.

Note: If a vehicle is brought in for service with a customer concern of rear speaker rattle, please confirm that the subwoofer amplifier gain control is set to the center detent position as identified below before attempting any audio component replacements.
Amplifier Gain Adjustment

The subwoofer amplifier is located in the luggage compartment behind the driver's side carpeted side panel just forward of the battery. Use the procedure below to adjust the amplifier gain.

1. Open the vehicle luggage compartment.
2. Remove the luggage compartment floor carpeting.
3. Remove the small form fit battery access panel on the driver's side of the luggage compartment.
4. Looking through the battery access panel, you should be able to see the subwoofer amplifier mounted to the rear wheelhouse ahead of the battery.

Object Number: 2320199 Size: SH
Click here for detailed picture of above image.
5. The gain control (1) is located on the underside of the amplifier (facing the trunk floor) as mounted in the vehicle.
6. Reaching under the carpeted driver's side panel luggage compartment panel, you should be able to feel the thumbwheel. Turn the control to the right for more gain, and to the left for less. The control is equipped with a center detent, which is the recommended setting.
7. Adjust the control as preferred.
8. Replace the luggage compartment floor carpeting.
9. Replace the battery access panel. The panel is easiest to install if you locate and seat the two end tabs first, then squeeze the panel to seat the remaining four tabs.
10. Close the luggage compartment lid.

[brewski6.0l]

I looked in the battery compartment,didn,t see anything that looked looked like a knob. Is this knob a "snipe hunt" ?

[GRRRR8]

I posted a link to it in your last thread about it. :)

[Chewy]

Merged with existing info thread!

[black widow g8gt]

ok i did it to mine sounds good i put the bass, treble, and eqboost on 2 then put it on rock has any one had any problems messing the speakers up or anything. whats the best settings?

[Larry GT]

Many informative (and hopefully useful) posts. Fading and the lack of bass tone may well be remedied - still don't know what that silver box is under the under the rear deck, though it does appear to serve some sort of audio function.

[Belo]

just did this finally. Thanks for the guidance. Bass seems a little better. Good thing I have 2 JL audio w3's coming in the mail though.

Anyhow, maybe I missed it, but someone should have mentioned you have to pull the 2 plastic tabs and the carpet back. I was under the impression i could do this through the battery access port, which is most definitely not the case, at least not on the 09.5's. Anyhow, wasted all of about 5 minutes figuring it out, but I thought I'd help to save someone some aggravation.

-B

[hflores3]

I must have turned the knob seven hundred rotations before I realized it was the
mounting screw LOL...

Damn!! Now this was hilarious!!

[JonnyG2132]

Just did the bass mod and it sounds really good. Did most of you just turn it all the way up?

[SRG963]

Just did the bass mod and it sounds really good. Did most of you just turn it all the way up?

I have mine set at half since I've added a 12" sub.

[DRCUSTOMPARTS]

Just did the bass mod and it sounds really good. Did most of you just turn it all the way up?
I turned it all the way up, plus I turned off the EQ so I can adjust the bass & treble and it sounds good.

[JonnyG2132]

what are your adjustments? i cant get mine to sound that good at high volume(20). I have my treble at 6 and bass at 3. I know nothing about adjusting this stuff so any help would be great.

[SRG963]

what are your adjustments? i cant get mine to sound that good at high volume(20). I have my treble at 6 and bass at 3. I know nothing about adjusting this stuff so any help would be great.

You can try turning the DLL off, the EQ off, and auto adjustment off. I have my T at +4 and B at 0 to +2 depending on the music.

[JonnyG2132]

ok thanks. what is DLL?

[IndyGT]

You can try turning the DLL off, the EQ off, and auto adjustment off. I have my T at +4 and B at 0 to +2 depending on the music.

Does the auto adjustment effect effect sound quality that much? I thought it just raised the volume to counter road/wind noise as speed increased. It doesn't really seem as noticeable as it did in my '06 Impala SS anyway. I'll have to try turning it off.

[SRG963]

Does the auto adjustment effect effect sound quality that much? I thought it just raised the volume to counter road/wind noise as speed increased. It doesn't really seem as noticeable as it did in my '06 Impala SS anyway. I'll have to try turning it off.

I don't think the auto adjustment would cause any sound quality problems in this car. I have had problems with that feature on previous cars, so I turn it off by default.

[JonnyG2132]

I just want to know how to get the best sound out of our systems? what should i turn everything to?

[SRG963]

I just want to know how to get the best sound out of our systems? what should i turn everything to?

To me, the system sounds the best with all the extra options turned off (DLL, EQ, Loudness). Then adjust the B and T to your taste, I like +4 treble and 0 to +2 for the bass depending on the song. Sound is objective, so what sounds good to me, may sound off to you. It's always best to start with a flat line, then boost what you want to get the sound right.

[xXXNoMVAMXXx]

Going to have to try this until i get my subs

[Seattle09GT]

To me, the system sounds the best with all the extra options turned off (DLL, EQ, Loudness). Then adjust the B and T to your taste, I like +4 treble and 0 to +2 for the bass depending on the song. Sound is objective, so what sounds good to me, may sound off to you. It's always best to start with a flat line, then boost what you want to get the sound right.

Sage advice. I was running with DLL off, EQ off, but I do run loudness on. I run with treble +6 and bass +3 to +5, depending on the music. My hearing is trashed so I suspect this would sound like crap to a lot of people. The part about turn everything off, go to Bass 0 and Treble 0 and adjust from flat until you're happy is spot on.

[Napalm]

OK so I know this is a bit late but. I was trying to do this today at work (yes really). I just got the car last night. This is forward of the battery, I don't think I can fit my hand up there.

Am I missing something?

[Seattle09GT]

OK so I know this is a bit late but. I was trying to do this today at work (yes really). I just got the car last night. This is forward of the battery, I don't think I can fit my hand up there.

Am I missing something?

You might have to remove the trim piece on the side to get access, the knob itself is on the amp, IIRC forward of the battery but at the BOTTOM of the amp.

[speedisking]

I finally did this and what a difference it makes. I have pretty long fingers and my hands aren't too fat so I slide my hand in between the battery box and the trunk panel and I could just barely reach the knob, but you can do it without pulling the side panel.

This simple mod is enough to keep me from installing a sub box.

[Elhc86]

Can I get a pic of the amp

[SRG963]

I found a pic of the amp mounting bracket. Sits slanted in front of the battery.

http://i148.photobucket.com/albums/s18/lstd_trackdays/Amp%20install%20to%20G8%20GT%202009/DSCF4318.jpg

The LOC connected into the factory amp harness
http://i148.photobucket.com/albums/s18/lstd_trackdays/Amp%20install%20to%20G8%20GT%202009/DSCF4319.jpg

[wreckwriter]

Will the radio quit working if the amp is removed?

[I12XLR8]

Can I get a pic of the amp

This is the best I can do - hope it helps.

[Elhc86]

Thanx

[SRG963]

Will the radio quit working if the amp is removed?

I would assume just the rear and subs would stop working. The front doors and center speaker runs off the head I believe.

[Anon]

Tried looking for the amp. No luck. Could mine be somewhere else. Two box looking things on the underneath of the back deck. 2009.5 G8 GXP.

I have those two boxes as well, one is for the XM radio, sadly I have no idea what the other one is for. The amp is in the same place on your vehicle as it is on everyone else's.

[TomPierce]

I have those two boxes as well, one is for the XM radio, sadly I have no idea what the other one is for. The amp is in the same place on your vehicle as it is on everyone else's.

The other box is OnStar.

[Metal Man G8]

Bass mod done! Never worked so hard to get more sound lol. Worth it though, mess with the audio settings and its surprising how much of a difference it can make. I put the knob to max and turned it back just a hair.

[firefighter]

Gotta do this one too...

Sent from my SM-G900V using Tapatalk

[FCNFST]

How much force does it take to turn the knob? I can barely get my finger on it, but I don't know if I'm turning it or not. I played a song with heavy bass during my attempt to adjust, but I couldn't tell if there was a slight difference or if it was a placebo effect.

[SRG963]

It should turn easily. I left mine set in the middle.

[FCNFST]

It should turn easily. I left mine set in the middle.

Are you basing the middle off of an estimate, or is there a notch which indicates?

[firefighter]

Are you basing the middle off of an estimate, or is there a notch which indicates?

IIRC there was a click felt midway...

Sent from my SM-G900V using Tapatalk

[S.D.M.F]

For those who cant find the amp.....this might help:

NOT my youtube clip

https://www.youtube.com/watch?v=pJOXR90l4q8


https://www.youtube.com/watch?v=pJOXR90l4q8

[NmE0208]

Sweet! This couldnt be any clearer. I scratched up my wrist the first time trying to reach it without removing anything lol I really dont know how some guys managed to do it that way :uhm: Good find!