SoundXtreme ST-680 5x7/6x8" 3-Way Coaxial Speakers

The SoundXtreme ST-680 is a pair of 5x7/6x8-inch 3-way coaxial car speakers designed as a practical replacement for worn or underperforming factory door or rear-deck speakers. Their dual-fit sizing is intended for vehicles that use either a 5x7-inch or 6x8-inch speaker opening. The pair uses a 4-ohm design for connection to compatible car-audio systems.

These speakers are suited to everyday listeners who want a straightforward full-range speaker upgrade without adding separate tweeters or external crossovers. The coaxial layout places the high-frequency driver within the woofer assembly, keeping installation comparatively simple. A 3-way architecture combines the mid-woofer and tweeter elements in each speaker assembly.

The ST-680 is specified for 350 watts peak power per pair, with a recommended amplifier range of 10 to 75 watts RMS per channel. Its 90 dB sensitivity and 45 Hz to 20,000 Hz frequency-response specification describe a speaker intended to cover bass, vocal, and treble ranges in a conventional car-audio setup. Power should be matched to the stated RMS recommendation rather than the peak rating.

A polypropylene mid-woofer cone works with a polyester-foam surround, while the high-frequency section uses a 1/2-inch PEI balanced-dome tweeter. The speaker also uses a neodymium motor structure and a stamped-steel basket. SoundXtreme lists EVC, or Extended Voice Coil, technology as part of the speaker design.

The ST-680 can be used with a compatible factory radio or aftermarket head unit, or with an amplifier that delivers suitable power at 4 ohms. It is a sensible option when replacing speakers in vehicles with compatible 5x7-inch or 6x8-inch mounting locations. Confirm the vehicle opening, mounting clearance, wiring connection, and speaker polarity before installation.

Key Features

• Dual-Fit 5x7/6x8 Size: Supports compatible oval speaker locations in either common size format.
• 3-Way Coaxial Design: Integrates multiple driver elements within each speaker assembly.
• 4-Ohm Impedance: Matches many conventional car-audio speaker circuits.
• PEI Dome Tweeter: Adds a dedicated high-frequency driver for treble reproduction.
• Polypropylene Mid-Woofer: Provides the primary cone for midrange and lower-frequency output.
• Stamped-Steel Basket: Provides a rigid structural frame for speaker mounting.

Design & Installation

The ST-680 combines a polypropylene mid-woofer cone, polyester-foam surround, 1/2-inch PEI balanced-dome tweeter, neodymium motor structure, and stamped-steel basket. These materials form a conventional coaxial speaker construction with the tweeter integrated into the main speaker assembly. The listed frequency response is 45 Hz to 20,000 Hz, and listed sensitivity is 90 dB.

Verify that the vehicle accepts a 5x7-inch or 6x8-inch speaker and that the opening supports the stated 5 x 7-3/16-inch cutout dimensions. The listed top-mount depth is 3/8 inch, but installers should measure available clearance at the intended location before fitting the speakers. The package is listed with speaker wire, screws, and a user manual; use correct polarity and connect only to a compatible 4-ohm audio source.