Quiet Airpump

Hi, this is my first post so please be gentle.

I have a 48" community tank and have been looking for a very quiet airpump for the past few weeks but to no avail.

Many years ago I invested in a piston type pump that had it's mechanism open and on display. Not only did it look good but it was very powerful and virtually silent. When I sold up, I stupidly let this go and can't remember the make and the supplier I bought it from is no longer trading.

Please can anyone help with this?

In the 1950s I had a piston type air pump; the piston itself was a piece of leather between two washers. It's not unheard of for those things to work backwards and suck water out of the aquarium. In any case, a check valve is a good idea. The vibrating type pumps are much cheaper to own, and some of them are fairly quiet. However, they all buzz if you restrict the flow of air. I have several Whisper pumps that work fine. Sometimes if a pump starts to make a noise, you can open some air valves or put the thing on a rubber mouse pad.