Maybe a new carb?

I have had the occasional TQ 'whistle' at small throttle openings. These were carbs that had no shaft wear, so I do not believe it comes from the air leakage at the shaft. Only had it happen on modified engines that needed more idle air. I think, but have no proof, that the noise is a combination of the particular air speed, air volume & throttle opening that coincide to produce the whistle...like blowing across the top of a Coke bottle.