HELP! 2 Under 2 - Toddler struggling

[TheirMuva]

Any suggestions/ help/ advice would really be appreciated.
I have a 22 month old and a 12 weeks old. My toddlers HATES the sound of the baby. Whether baby is crying/ talking/ laughing the toddler will have a melt down. So he basically cries ALL DAY LONG!!
I've tried giving him cuddles/ reassuring him that baby is just talking.
I've tried being more firm by not giving his melt downs much attention- i just tell him "it's ok" and let him cry- which can go on for hours!
We spend a lot of alone time together without baby. Playing, reading, etc. And i also make sure to play with both at the same time so he realises the baby is part of the family.
What can i do to get him used to baby noises? This is so draining!

Could you get your toddler noise-cancelling headphones, the sort they make for wee ones at festivals and other noisy events? Then he could get used to baby's noises at his own pace without it being so stressful for everyone.

Is he sensitive to any other sounds at all?

I didn't think of that! Thanks so much. I'm going to order some from Amazon and see how it goes.
He's fine with noise and other toddlers, but we've recently had a friend and her 8 month old over and he was acting out whenever her baby made a sound too. I don't know why he hates the sounds babies are making.
Maybe I should get his ears checked just incase