Does tv sound better with av receiver?

Yes - but for several strange reasons.

Most HDTV's today are flat panel. The speakers are mounted on the BACK and fire down/up/to the sides. This is horrible for sound.

A budget sound-bar that simply points the speakers forward gives a great improvement to the clarity and quality of the sound.

Many TV shows do not use the subwoofer, but the few that do - an AV Receiver with a subwoofer can create a much better sound experience.

So the best/cheapest way to get better TV sound is a sound bar. (Make sure to get one that accepts optical).

A full 5.1 Surround Sound system is better still - but it really shines for HBO and movies, not as much an improvement with normal TV shows.

In most cases yes..even the most basic name brand entry level speakers that are designed to work with an AV Receiver will sound better than probably 90% of the TV speakers out there...Take a look at AV receivers by Yamaha Onkyo and Pioneer for entry level brands that offer good deals and entry level speakers by Energy; Pioneer (designed by Andrew Jones ) and Fluance speakers.....

Not unless you have decent speakers to go with the Receiver....

obviously, if you can supply appropriate speakers as well

obviously, if you can supply appropriate speakers as well