I'm pretty certain the installer will tell u in a 15 second phone call the flash that was used. They are generally not named specifically but are as u stated either a 0/4, 2/6, 2/8, etc. The RF Flash is prob one of the only named ones
If u can get confirmation on that flash it sure will save u a lot of **** pain moving forward with any upgrades.
Or, get an aftermarket HU of course.

T

 

as stated, not all of the flashes address the eq curve issues, some just enable more/different functions in the head unit. some do address the eq curve issues, and there are several that are named, but they are usually named after the manufacturer that had something to do with their development, IIRC, i've seen JM, RF, Soundz, and a couple of others in my software. the only ones that i have actually used are the RF and some of the different non branded flashes, because i dont own a bike with a flashable head unit, i've not been able to experiment and take measurements or do any SQ testing. I do know that the RF flash for the 2014-2019 bikes does actually make a difference.
m

 

Any idea which flash is the flattest?

 

Yes. The Sony 7000 is the flattest.

T

 

unfortunately i have no idea which one is the flattest, because i don't own or have a bike available for me to test with the o-scope and rta at the same time.
m

 

Have you tested this one yet? Better than the alpine?

 

Ok my audio guy said he used the Harley flash. So as little as I know, I'm thinking I should get some line levelers in there.

 

That's not enough information. Most flashes are Harley flash. Unless he said he used the 0 amp 4 speaker Harley flash. Commonly referred to as the Ultra flash.

 

Yes. As I said above. That's the one he used. 4 speakers no amp.

 

Then you need line levelers.