Sure you can buy a camera with a good optical zoom and when you use it, the audio is abysmal, because while the scene is drawn closer by the optics, the sound is not and reverberates (in a closed environment) or disperses (in an open one) before it reaches your mike.
One solution is to get a better microphone, assuming your camera supports external mikes.
Another solution is to get nearer the scene, but this is seldom truly possible, unless you are the stage photographer and even in such case your presence may a bit distracting for the performer.
There is maybe another solution, which I tested on saturday, during the annual “Hauskonzert” of my daughter’ piano school, which is traditionally hosted at our place.
What you see above is the concert room seen from the very back: while I sit on my chair, I am controlling the recording through an app on my smartphone (yellow detail): I can start and stop and zoom in and out right from the smartphone.
But the lens capturing the scene is that of the remote Sony QX-10 mounted on a tripod right next to the piano (red detail); it is hardly visible and it does not bother the performers, while allowing for the best viewing and recording angle; and being so close the sound is as good as it gets.
In the blue detail you see the actual device which is truly very small and light; it is battery operated (battery is good for about 1 hour of recording, although you can of course hook it to a power pack or its own power supply if you need more juice) and has a local micro-SHDC card; the device acts as a wifi hotspot to which you connect the smartphone, but once recording has started, you can log off and it will continue recording, up to the max 2GB file size.
The item is so light it can be mounted on top of a self-standing monopod with a ball head for an even smaller footprint: I am considering buying a second one to place at another viewing angle and do a two-camera directing from my smartphone: way cool.
Sony Qx-10 (EUR 139) – BTW, Sony also sells a pointless and much more expensive QX-100; ships both products with a clumsy and equally pointless smartphone attachment. Bag and micro SDHC are extras (ha!). Given they’re so clueless about an actual use case, one must thank God they provided it with a standard mounting screw at the bottom.
Self standing monopod (EUR 135) – if you already have the monopod you can purchase the three alu feet on their own for about half the price.
Ball head (EUR 25) – unless your monopod already has it; but then it will be more expensive than the one linked above. Really useful to achieve the perfect viewpoint. Even better would be a gooseneck mount akin the ones you attach through a suction cup to your windshield, but could not find one that mounts on the tripod / monopod mounting screw.
The setup is not super cheap, but with two of these you achieve a result you could not achieve without semipro (much more expensive) tools.