Lude Generation

I've been trying to attach a small mp3, but won't let me attach file.

Basically, once the engine gets up to temperature it sounds kinda high pitched and errr warbles on idle, (hard to describe). Slightest touch of throttle and it sounds as it should.

Car due for service and a few other bits so thought I might try and get it sorted. I've heard an ATR make the exact same noise on idle, so it may be an issue with the H22s?

I could WhatsApp the sound file to any of the H22 experts on the forum if that helps?

Any help appreciated so that I can hopefully direct the garage, they couldn't figure it out last time they checked the engine.

Could be some kind of belt noise?
Alternator bearings?
I'm guessing ofc.

I'd go for belt tension. I had chronic issues with my previous 1997 (H22A5) Prelude. It was the tension of the balancer shaft belt.

you could check the power steering belt and ps pump - ive heard them make some funny noises
might as well check all belts and pulleys on that side of the engine

Get a length of broomstick or similar to use as a stethoscope. You can localise the sound that way. But please be careful to keep clear of belts, pulleys etc!

Thanks all.
With the garage now and hopefully they'll sort. Downside is the bodyshop & garage are, post snow etc, totally booked up fixing knackered steering and suspension.
Decided to just leave it with Honda given the long list of jobs to be done. So I'll be without Lude for a few months, but, i'd rather they take time than rush to meet a deadline.