I have had my Tablo for right at a year now & I use it on 4 different TV’s throughout my home. Two simply utilize the TV speakers, one has a soundbar & the other has a 5.1 surround sound system. I may not exactly be an audiophile, but I do appreciate good sound thus my substantial investment into my surround sound system for my family room. Also when I purchased my first flat screen TV that only had rear facing speakers (which seems to be the only way they come any more) I found that the purchase of a soundbar (if not a surround sound system) is now a must.
With all this said, while Tablo lacks surround sound I don’t perceive any noticeable issue with the sound it does deliver. At least nothing more than the fact that I have to turn up the volume a few notches when I use Tablo vs my other TV sources - PSVue, Netflix & Amazon Prime.
For those of you who experience a noticeable sound issue, especially if it is noticed by those who don’t otherwise perceive a difference between a surround sound system & TV speakers & wonder why one would spend so much money on such a system (as my wife), then I would think you must be experiencing some sort of problem that is not normal for Tablo’s sound quality.