Speaker - Increasing/Decreasing Bass Level/Gain Control
INFORMATIONBulletin No.: 09-08-44-014
Date: August 07, 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.
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.
Disclaimer