Hello,
I, too had the speaker buzz/crackle problem. And, like many others on here, have not received any meaningful assistance from Roku. Fortunately, after doing a little research I was able to diagnose and FIX my issue. My Streambar now sounds like new again.
Bottom line (for me, anyway), this problem does not appear to be related to software updates and/or settings. Rolling back my firmware, changing settings, wiping/reset all had zero effect on the problem which is probably why Roku has limited options to offer.
What I did was disassemble the unit. Obviously not recommended for anyone who does not want to void their warranty and expect any kind of company support in the future. Also, there's a safety risk messing around with bare electronic components (I have an electronics background) But, because the sound was so bad I had nothing to lose because the next step in this process was the trash bin. Fortunately, Roku did an excellent job on the unit design; it's very easy to open up and look around if you're handy with a screwdriver.
Some others who took their Streambars apart noted finding "debris" rattling inside or finding a rip on one or more of the four speaker cones, which could cause the issue. My unit was pristine inside, so I had to look further. In audio circles, the number one cause of noise is wiring, so that's what I looked for.
First: each of the four speakers is connected to the amplifier by two wires with a connector. All of the wires looked to be in good shape (no pinches, crimps, etc) and the connectors themselves were firmly seated.
Second: I was able to test each speaker by unplugging three of the four and then play media. Rotating through all four, I was able to find one speaker that buzzed.
Third: I removed the problem speaker completely (held in by 4 screws) and took a closer look at the wires attached to the speaker itself. There's a black conformal coating painted over the solder joint which I scraped off using a pen knife, and after doing so it was apparent what my problem was: the wires appeared to be poorly hand-soldered to the speaker unit.
Fourth: Using a soldering iron, I removed both wires from the speaker and cleaned up the sloppy solder from the terminals. I cut the tips off the wires and re-tinned them, then re-soldered them to the speaker. I attached the connector to the board to test, and the problem was GONE.
My take on this is that the wires soldered to the speakers are the weak point, and are attached very inconsistently. Could be the heating/cooling from the electronics combined with vibrations from low frequency bass just caused one or more of the solder connections to crack, which was enough to cause the problem.
Hopefully this info helps you. Not counting the research and any time spent with "support"... implementing the fix and putting the unit back together took less than 30 minutes.
Good luck!!
