Tuning Tips for Velocity RZ65H 6.5 Inch Harley Speakers

These speakers should be crossed over with a high pass of 150 hz, at a minimum of 12db but 24db is recommended if it is available to you. The included 12db per octave passive crossover facilitates a smooth transition from the woofer to the horn tweeter. 

Equalization

In general, all pro-audio-type speakers really should have an equalizer (DSP) in the system. The RZ65H speakers kind of break that rule due to their exceptionally great frequency response. These speakers can be used without equalization, but the following is a list of tips if you do have an equalizer in your system.

At 8khz the response has a peak due to the tweeter's horn loading. Cut by 9.5db with a Q of 4.32. At 10khz the tweeter's response rolls off due to the high-frequency limitations of the horn, but the tweeter itself is capable of playing higher even without the horn loading, so boost the region between 10khz and 16khz with a high point of 6.5db at 12.5khz. If you have a parametric EQ you can simplify this by only boosting 12.5khz by 6.5db and lowering the Q to 1.6 to get the same result. Lastly. Play with boosting 3.15khz slightly to compensate for the woofer's upper limit roll-off. Do not add any boost to the low-frequency section (below 250hz). These speakers don't need it, and doing so will only over tax the speakers suspension and generate a lot more heat in the voice coil. Every 3db of equalization boost doubles the heat generated at the voice coil.

Below is a screenshot of typical adjustments for the RZ65H speakers mounted in the fairing of a 2019 Road Glide (radio flashed).