The Golden Rule of Tuning Harley Sound Systems
All Harley sound systems should be tuned to have a flat frequency response at max volume but the low and high frequency equalization should dramatically increase as the radio's volume goes down. The frequency response at all volumes below max should not be flat.
This can only be done with a factory radio and will not work with aftermarket radios. At medium and low volumes the frequency response should be nowhere near flat. All factory Harley radios have this feature built into them but no aftermarket radio has this feature. Not understanding this feature is the number one reason both consumers and professionals have a tough time tuning bikes.
How do you tune a Harley to take advantage of this factory feature?
The goal is to tune the bike for flat frequency response at max volume and to strip out the factory Harley speaker specific equalization while leaving the Harley volume dependent loudness equalization in place.
You do this by turning the amplifier gains all of the way down and then tuning for a flat system response with the radio turned all of the way up. Because you turned the amplifier gains all of the way down, the speakers are playing at normal output levels with the radio volume way up. This allows you to put a comprehensive tune on the system with the gains temporarily much lower than they should be. After which you will readjust the gains as normal. The end result will be a speaker system that has been optimized for perfect response when played wide open, but at lower than full volume the system will boost both the low and high ends of the spectrum and create an exaggerated loudness effect. When you turn the radio volume down, the built in automatic equalization feature will kick in on its own resulting in a very bold sounding system at all volume levels that doesn’t destroy the speakers at extreme volume levels. This is very important when actually riding the bike where there are a ton of noises that want to swallow the audio systems performance. When sitting in the parking lot it just sounds bad ass. When cranking up the volume the equalization will flatten out but the increase in volume more than makes up for it. A system tuned this way sounds impressive at any volume.
Harley radios actually have two levels of equalization built into them. Speaker specific equalization and automatic volume dependent equalization. “When you tune for a flat response at max volume you are stripping away the Harley speaker specific equalization but leaving the automatic volume dependent equalization in place.”
The automatic equalization that Harley built into their radios is designed for the human ear in a noisy environment and not for Harley brand speakers. This volume dependent automatic equalization is valid for all speaker types. The flat response equalization that you perform with the radio set to max volume replaces the factory Harley speaker specific equalization with new equalization that is specific to the new speakers that you are now using.
Once you have finished tuning your bike at max radio volume, reset your gains for max speaker performance as you normally would.
Important Tech Notes
- For especially loud systems. Tune with the radio two clicks down from max volume instead of 100% max volume as stated above. This will put a slight dip in both low and high frequencies when the radio is at full tilt boogie which is good for speakers as well as sound quality due to the way humans process sound differently at those kind of volume levels
- Do not attempt to set any equalization until after you have made proper crossover settings and thoroughly optimized speaker phase relationships.
- Never tune a bike that is not on a full blown automatic battery charger (at least 30 amps). Do not use a battery tender while tuning!
- If you are smart you will use an RTA when setting your equalizer. An RTA will allow you to breeze through your settings instead of going at it blind. All Velocity Speaker kits come standard with a Pro-Tune RTA. Check them out here.
Want this done for you?
All Live Tune enabled systems at American Hard Bag come with the tools and service required for this type of tune. With Live tune we connect to your bike via internet and we take care of all of these settings for you. See all of our Live Tune Enabled systems here.