Oldsmobile Firenza Speaker Size

Dashboard Speaker

Rear Door Panel Speaker

Oldsmobile Firenza Speaker FAQ

What speakers should I replace first in my Oldsmobile Firenza for better sound quality?

Replace the 4 x 10 inch rear door speakers first. These coaxial speakers handle most of your music's frequency range and moving more air than the 3.5 inch dashboard units. The rear doors typically get 15-25 watts RMS depending on your head unit. Dashboard speakers mostly fill in treble response - they're secondary. Focus your budget on quality 4 x 10 coaxials with sensitivity around 88-92 dB. The Firenza's rear door mounting might need slight modification since 4 x 10 wasn't super common by the late 80s.

Can I install component speakers in my Oldsmobile Firenza instead of coaxials?

Probably not worth it. The Firenza uses 4 x 10 inch rear and 3.5 inch dashboard locations - both designed for full-range coaxial speakers. Component systems need separate tweeter mounting locations which your dashboard setup doesn't really support effectively. Stick with quality coaxials that have good tweeter integration. Look for speakers with 4-ohm impedance to match factory wiring. You'd spend more on custom tweeter mounting than you'd gain in sound improvement for this particular configuration.

Why does my Oldsmobile Firenza have such an unusual 4 x 10 inch speaker size?

GM used 4 x 10 speakers in the early-to-mid 80s because the oval shape fit better in door panels while providing more cone area than round 4 inch speakers. It's roughly equivalent to a 5.25 inch round speaker in surface area. The 4 x 10 format handles midrange frequencies around 80Hz to 4kHz pretty well. However, replacement options became limited as the industry standardized on round speakers. You might find better selection looking at marine or vintage car audio suppliers. Power handling typically ranges 20-40 watts RMS for aftermarket 4 x 10 coaxials.

What's the frequency response difference between dashboard and rear door speakers in the Oldsmobile Firenza?

The 3.5 inch dashboard speakers probably cross over around 150-200Hz and handle mainly midrange to treble - maybe up to 15kHz depending on tweeter quality. Your 4 x 10 rear door speakers should cover 60Hz to 12kHz or so. There's overlap in the midrange which can cause phase issues if both speaker sets are running full-range off the same amp channels. The dashboard position gives you better stereo imaging though. Some people disconnect the dash speakers entirely and just run the rear doors. Depends on your head unit's EQ capabilities.