A lot of the universal controllers have mics on them but none of them work with the voice search. Most of them won't bother stating that on their page, so if you think you have found one that may work, get the seller to confirm before you bother buying it.

A workaround might be to buy something like this USB microphone or this one to replace the mic on your control, and then use a universal for all the other functions. The potential problems with this are that:

a) Certain usb mics might not work (or androidtv might break this functionality in future updates). I currently use a C310 webcam, until I can find another cheap usb mic locally. It works well. As a side note, I did actually have my hopes up that I could use the webcam for Skype on my TV, but Skype won't work on androidTV. Also be aware that you need to sit 2m from the mic - some people with big TVs in big houses complain that the accuracy drops too much when they're 3m or more away.

b) You may have to use your universal remote to navigate to and enable the voice search icon, rather than activating it directly with a button on your universal remote: I don't think they can 'learn' the microphone key action from your original remote.

Also remember you can use your phone or tablet as a remote/mic with the Android TV App . It's too much of a hassle for most people to grab their phone every time they want to search, but I just thought I'd mention it.