BMW 335is Speaker Size

Rear Side Panel Speaker

Front Door Panel Speaker

Center Dash Speaker

Below Seats Speaker

Rear Deck Lid Speaker

BMW 335is Speaker FAQ

Which speakers should I upgrade first in my BMW 335is for the biggest sound improvement?

Start with the front door panel components - the 4 inch coaxial speakers and 1 inch tweeters. These handle most of your mid-range and vocal frequencies. The front stage creates the primary soundstage in your BMW 335is, so upgrading here gives immediate results. Look for components rated around 75-100 watts RMS with 4-ohm impedance. The factory crossover might need adjustment... but that's getting complex. After fronts, consider the 8 inch subwoofer below the seats if you want more bass presence without adding external amplification.

What's the difference between the coaxial and component speakers in my BMW 335is setup?

The front door panels use component speakers - separate 4 inch drivers and 1 inch tweeters with individual crossovers. This typically sounds better because each driver handles its optimal frequency range. The rear side panels and other locations use coaxial speakers where the tweeter sits mounted in the center of the 4 inch woofer. Coaxials are simpler to replace but don't image as precisely. Your BMW 335is has this mixed setup probably for cost and space reasons. Component systems generally perform better in the 2-8kHz range where vocals live.

Can I replace the BMW 335is rear side panel speakers without affecting the front soundstage?

Yes, the rear side panel speakers won't dramatically alter your front imaging. You have both 1 inch and 0.75 inch tweeters back there, plus 4 inch coaxials. The smaller 0.75 inch tweeters probably handle upper frequencies around 8-20kHz. Replacing these with quality units rated for 50-75 watts should work fine. Just match the impedance - likely 4 ohms for the BMW 335is system. The rear speakers mainly provide ambient fill and rear passenger coverage. Though... if your head unit has fade controls, you might want to reduce rear levels after upgrading to maintain proper balance.

Why does my BMW 335is have so many different speaker locations and how do they work together?

Your BMW 335is uses a distributed speaker system for wider coverage. The center dash 4 inch speaker handles dialogue and center imaging. Front doors create the main stereo field. Rear side panels fill in for passengers and ambience. The rear deck lid 4 inch speakers add depth. The 8 inch subwoofer below seats covers bass from roughly 40-200Hz. This multi-point approach can sound great when properly balanced... but it also means the factory head unit has complex processing. Each location serves a specific purpose in the overall soundfield, which is why randomly upgrading individual speakers sometimes disappoints.