I have been pedalling on the small chainring. I idea is to pedal faster with less effort, with an average cadence between 90-100 rpm.
This past week, maybe longer, I have noticed an annoying chatter when I’m pedalling in some gears. So annoying that I would change into a larger or smaller one just to quiet it down. It kept getting worse despite my attempts to adjust the cable tensions, or the position of the front changer.
Today I had had enough. I rode on the large chainring. There is no chatter there.
I was once told that pedalling on the large ring develops strength. I was climbing up one of the local mountains, when I came along side a young rider turning a big gear. He said he did this climb once every week or two pedalling in the largest gear he could. It developed power he said.
Well today was supposed to be a slow day. A recovery day. A Zone 1 day. I did 48 km on the large chainring averaging 25 kph but with a slower cadence. Eighty-one. So, I was turning a larger gear but spinning about 10 rpm slower on average. Did I feel more tired? No. It was all in Zone 1, at a lower heart rate. Did I travel faster faster? No. The same as I do in a lower gear but at a faster cadence. Did I develop more power by doing this? I don’t know. But it certainly felt comfortable, and easy. Maybe I am getting stronger.
I’ll stay on the large chainring until I can figure out the cause of the chatter. At first, I thought it was the BB but I have now isolated the problem to the small chainring. Maybe it is loose.
PedalWORKS 
I hate any unidentifiable noises on the bike, it spoils the ride,and I can’t rest til I find the cause,a bit ocd some might say.
Your chatter can be one or all of a few things.
Worn small chainring seems unlikely or it do it on all cogs,but worn sprockets on the cassette if it’s the cogs you use the mostly is quite possible,if as you say the noise stops when you change to a different cog. or even a worn chain or jocke wheels..or an out of line rear derailleur
As usual with these things it can be a case of trial and error,trying he easiest things first.and hope you get lucky with the first port of call.
Thanks Paul. Yeah. I’m working through the list. The chain and cassette were new 10 months ago so should be ok. There isn’t 50% wear on the chain. The crankset is only 2 years old. And since I ride several bikes, there’s not that much wear on the rings. I suspect since I have travelled recently, the derailleur is out of alignment. I don’t have a bike stand here so I can’t get a really good look.
Difficult without getting it in th bike stand.
I’d have thought a bent hanger would cause a problem in all rear cogs.
If you think that’s the cause you could resort to the old brute force and try bending it back into line,it’s worked for me in the past,but only on Mtbs mind.
Not sure I’d try it on an expensive dura ace hanger though,unless your confident that’s the issue.
Again I replaced the hanger last year for that reason. If I can’t figure it out I may have to take it to a shop. I hate to do that. I generally don’t let anyone touch my bikes.