BF 45 - 4 OHM

Overview

The Visaton BF 45 is a dynamic full-range loudspeaker driver designed for compact audio reproduction. It features a nominal impedance of 4 ohms and a power handling capacity of 10 watts. The unit utilizes a ferrite magnet system to drive a paper cone diaphragm with a rubber surround, ensuring reliable mechanical operation. Key acoustic parameters include a resonant frequency (Fs) of approximately 85 Hz and a total Q factor (Qts) of 0.62, indicating suitability for sealed or vented enclosures. The effective radiating area is defined by a diameter of 100 mm, providing balanced midrange and treble output within its specified frequency range.

Feature Summary

• Dynamic full-range transducer design integrating bass, midrange, and treble reproduction in a single unit
• Robust construction featuring a paper cone diaphragm paired with a durable rubber suspension surround
• Efficient magnetic circuit utilizing a ferrite magnet structure for consistent force factor
• Compact physical dimensions optimized for integration into small-volume speaker enclosures

Applications

• DIY audio projects requiring simple two-way or full-range speaker builds
• Replacement drivers for vintage radio and communication equipment restoration
• Small portable speaker systems where space constraints limit driver size
• Educational demonstrations of electroacoustic principles and loudspeaker mechanics

Procurement Notes

Verify the specific suffix code on the order confirmation to ensure the correct impedance variant is supplied, as Visaton offers multiple resistance options within the BF series. Confirm that the terminal type matches your existing wiring harness, typically spade connectors for this model. Check the manufacturing date code if long-term storage is planned, as rubber surrounds may degrade over extended periods without use. Ensure the enclosure design accounts for the specific Thiele-Small parameters provided in the official datasheet to achieve intended performance.

Selection Notes

Select this component when a single-driver solution is required for limited space applications. The 4-ohm impedance aligns with standard amplifier outputs and battery-powered audio devices. Consider the Fs and Qts values to determine appropriate enclosure volume; lower Qts suggests better control in vented designs. Evaluate the power rating against the expected signal levels to prevent thermal compression or mechanical failure during peak usage scenarios.

Part Context

The BF series represents Visaton's line of budget-friendly, high-performance full-range drivers. These units are engineered for versatility, balancing cost-effectiveness with acceptable sonic fidelity for general-purpose audio. The BF 45 specifically targets the 4-inch class, offering a compromise between low-frequency extension and high-frequency dispersion. This series is widely used in hobbyist electronics and entry-level audio hardware due to its availability and predictable behavior.

Replacement Considerations

• BF 45 - 8 OHM
• BF 45 - 16 OHM

FAQ

What is the recommended enclosure type for the BF 45?

Due to its Qts value of 0.62, the BF 45 is suitable for both sealed and vented enclosures, though it often performs well in small sealed boxes for full-range clarity.

Does the BF 45 include a built-in crossover network?

No, the BF 45 is a raw driver unit. Any crossover components must be added externally by the user if a multi-way system is desired.