The sound delay is a very common harmonium issue.

If you will ever go to some harmonium shop and the seller will present to you some harmonium models from his shop there is a big chance that during the presentation he will pump the harmonium a lot to show you how nice and powerful the sound is.

Almost every harmonium is nice and powerful if you supply a lot of air to it. But, what will happen if you try to play harmonium while pumping the bellow softly? The sound delay issue can be recognized during the soft pumping and this video shows you how to fix the delays.

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