Spazz, sounds like you know what is going on, but you lost me, way too much info for my mind, and I ( we ) appreciate your help, but my radio is stock on 19' Street Glide Special and sounds clearer with engine shut down and ign on, what is your thought on the system, should I turn off the AVC, or is this the nature of the beast? Thanks.
Now to answer your question....
AVC will work as intended for 2014-current STOCK systems without worry...
EXCEPT for BOOM II systems... Either FACTORY CVO systems or upgraded BOOM II
AVC MUST REMAIN under 3 bars or you will start blowing speakers. HD will NOT tell you this.... but I will.
Read below to understand why it sounds different ON and OFF
Lets explain a few things... just for info...
Ok... let me try and explain HD's madness the BEST I can....
The head units are the same... all 6.5GT's all 4.3's and all the 6.5GTS's... they are identical units respectively.
The difference is the configuration selection for each bike....2 speakers... 4 speakers 6 speakers or 8 speakers... AMP 1 AMP 2 or NO AMP or BOTH AMPS.... location of speakers not really an issue here.
The configuration is within a BINFILE that is flashed to the head unit via Digital Technician ( DT= Harley's laptop for hooking to the ECM ) or a Scan Tool ( Aftermarket unit that connects your PC to your bike via the ECM)
Not gonna go into too much detail on this.. it can get confusing... LOL
OK... so EACH BINFILE has its OWN 'instruction set' on how the radio should work/perform.... this is done via the internal DSP (Digital Signal Processor) Once a configuration is selected, the BINFILE is uploaded to the head unit called a FLASH.
Each BINFILE has a 'sister' to it as well... for example... BIN199_OFF is related to BIN199_ON which are similar is parameters, only one controls output when bike is OFF and one when its ON. ( this is MY understanding ) configured to sound 'best' under each condition.. running or not running.
The BINFILE has a preset selection of "EQ parameters" that, when volume is adjusted, it changes output of the head unit.... When its low volume, you have a decent overall mixed audio of decent midbass and treble.... as you increase volume, the EQ automatically adjusts itself... meaning the louder you turn it up, the bass signals are decreased and treble is increased incrementally. Higher frequencies create less distortion and can be increased to hear them better over lower tones in bass.
The AVC ( Auto Volume Control or SPEED CONTROL ) alters this EQ in the binfile on the fly....changing the output you hear.
All that being said.... when you are introducing aftermarket equipment, its important to understand that the aftermarket amps NEED the most stable ( non-fluctuating ) signal FROM THE HEAD UNIT to perform at its optimum. Since the OUTPUT of the head unit runs to the INPUT of the amp.... This signal must be configured to the FLATTEST EQ CURVE possible coming from the deck.. meaning you don't want an increase of volume to be able to change the output signal... EXACTLY WHAT AVC DOES!
Therefore... the FLATTEST EQ curve you can achieve on these units is 8 Speaker ON/ 2 AMP ON. This will insert a BIN135_OFF into the head unit and attain this goal. and AVC MUST REMAIN OFF!
Heading spinning yet? Mine is... hehehe!
