The GMT400 (1988–1998) Sierra/Silverado has quality speaker positions in the front doors. Here’s how to upgrade for significantly better audio.
GMT400 Factory Speaker Locations:
- Front door: 4" x 6" or 6.5" depending on year/trim
- Dash tweeters: Optional on some trims
- Rear jump seats (extended cab): 4" or 6.5" speakers
Upgrade Approach:
Front Door Speakers (Most Important)
The front door speakers do most of the work. Replacing the factory speakers with a quality set makes the biggest audible improvement.
For the 6.5" positions, consider Polk Audio DB652 ($65), Pioneer TS-A1670F ($55), or Alpine SXE-1726S for a step up.
For the 4x6 positions, Polk Audio DB461P, Kenwood KFC-1666S are well-reviewed.
Rear Speakers (Extended Cab)
If your GMT400 extended cab has rear speakers, matching brands for front and rear creates consistent sound.
Amplifier:
The factory GMT400 radio has minimal power output. An aftermarket amp (50–100W per channel) dramatically improves volume and clarity. Route the amp signal from the Kissound 7" Double DIN preamp outputs for clean signal.
Complete System Recommendation:
For under $400, you can have:
- Kissound 7" Double DIN head unit: ~$90
- Front speakers: ~$80
- 4-channel amp: ~$120
- Installation: Your time
This completely transforms the audio experience.