Jim,
[/size][/color]There are boat loads of people who have described the pop corn issue on this forum, AdvRider, reviews on Revzilla, Amazon, etc, etc. The methodology I initially stated says you need to have four units to do a test on the 20s is based on almost every case the 20s pairs and sets up an intercom connection that works fine but exhibits noise at 3 or more. Sena will tell you that at two users you are using the HD intercom but at three you go back to the standard intercom. I have two cases open with Sena Help Desk. The first came back telling me to restore firmware 1.6.3 over my latest and greatest 1.7.7. Problem is that my unit gives a Cannot Connect to Server error. What server??? I started the second case was to get the old firmware to load. When they could not get it to load they said my unit was too old. This was my response to them.
Ticket #213524: Sena 20S Group Intercom returned an answer that I needed to replace firmware 1.7.7 with 1.6.3. We got absolutely nowhere at accomplishing that. Michelle insisted the noise issue on the 20s was an interference. I AM an EXPERT on interference. I was in the Electronic Warfare section of NSA and was in charge of solving interference issues across DOD. This issue is not interference. Everything points to a problem with the firmware which SENA seems to want to deny. The fact is that going back to an older version off the firmware HAS produced a solution to the problem, BUT neither I nor I assisted by help desk staff has not been able to get my unit back to that version. That being said, keeping up with latest version of firmware as recommended by Sena in numerous locations has caused my unit to NOT PERFORM as stated in all advertising of the Sena 20s.
I WILL NOT be buying ANYTHING from Sena again. Back to the experimental method I listed above. If you follow the method outlined above using the number of units I list, you WILL get results that are valid, accurate and dependable. If you don't, what you will get is random results. But as Norm commented, getting four people who know what they are doing with the right equipment seems to be really, really hard to exceed practical limits.
Rod