when playing DVDs that were perfectly audible previously. It's gotta be something simple, yet unfathomable to this philistine.

Not enough information given.

So cannot be absolutely specific.

If you are using SCART make sure the plugs at both ends are properly pushed in.
If you are using HDMI make sure the DVD is configured to send PCM (or LPCM) stereo over HDMI and not Dolby Digital or the like.

It helps to know what makes and models of kit you have and exactly how they are interconnected to give more precise advice.

Thanks for replying Chris. TV is a Panasonic Viera, DVD player is an old Pacific I paid a quid for, but it usually works fine. They are connected by a SCART.

more than likely a scart issue then.

they always used to cut out on sound if the lead wasn't fully plugged in.

try a different cable.

failing that..... time to upgrade to a blu-ray player?