BMW 640i Speaker Size

Rear Side Panel Speaker

Center Dash Speaker

Front Door Panel Speaker

Rear Deck Lid Speaker

Below Seats Speaker

BMW 640i Speaker FAQ

Which BMW 640i speakers should I replace first for the biggest sound improvement?

Start with the front door panel 4-inch coaxial component speakers. These handle most of your midrange frequencies and vocals. The BMW 640i's front door speakers typically run around 4 ohms and 20-30 watts RMS. Replace the front door 1-inch tweeters next - they work together as a component system. You'll notice clearer highs and better stereo imaging immediately. The 8-inch subwoofer below the seats comes third if you want more bass impact around 40-120 Hz.

What's the difference between the coaxial and component speakers in my BMW 640i?

Component speakers separate the tweeter from the main driver. Your BMW 640i has 4-inch component speakers in the front doors with separate 1-inch tweeters. This design allows better frequency separation and positioning. The rear deck lid and side panels use coaxial full-range speakers - tweeter and woofer built into one unit. Coaxial speakers are... well, they're more compact but don't give you the same soundstage control. Component systems typically handle 2-8 kHz crossover points more precisely.

Why does my BMW 640i have so many tweeter locations?

BMW spreads tweeters across front doors, rear side panels, rear deck lid, and center dash for surround sound staging. Each 1-inch tweeter handles frequencies above 3-4 kHz. The center dash tweeter helps fill the soundstage gap between left and right channels. Rear tweeters create ambient sound reflection. This multi-tweeter setup can produce good imaging when properly balanced, though some locations might seem redundant. The front door tweeters typically get the most power - around 15-20 watts RMS.

Can I upgrade just the BMW 640i subwoofer without touching other speakers?

Yes, the 8-inch subwoofer below the seats operates independently. Most aftermarket 8-inch subs will fit the BMW 640i mounting points. Look for 4-ohm subs rated 50-100 watts RMS. The factory sub probably handles 30-80 Hz response. Upgrading this alone won't fix thin midrange or harsh highs from other locations. But if your mids and highs sound decent, a better subwoofer adds significant low-end punch. Check if your BMW 640i has a separate amp for the sub - this affects your replacement options.

What power ratings should I look for when replacing BMW 640i speakers?

The 4-inch speakers typically see 20-35 watts RMS, tweeters around 15-25 watts RMS. The 8-inch subwoofer might get 40-80 watts depending on your audio package. Don't exceed these power levels without amplifier upgrades. Most aftermarket speakers rated 25-50 watts RMS will work fine in the BMW 640i. The factory impedance is usually 4 ohms across all locations. Higher sensitivity ratings like 88-92 dB help if you're keeping the factory head unit. Component speakers often need slightly more power than coaxial designs.