Is a sealed environment always better for speaker enclosures?

Specifically when dealing with smaller, less powerful speaker. I am aware that certain sub woofers require venting, but I don't know how important sealed boxes are for midrange and tweeter.

Unfortunately for you, the answer is maybe. It all depends on the individual driver's specifications. Look up Thielle-Small parameters and how to use them to calculate enclosure types and sizes.

As for mids/tweeters, there is some merit in using an isolation enclosure in order to protect the smaller, more fragile cones/surfaces from the effects of hard hitting bass. Mostly it is to keep the bass from blowing out the active surface of the tweeters. Secondly, using an isolation enclosure keeps the bass from muddying up the higher frequencies, keeping the sounds coming from the mids/tweets more pure. You won't find such things on most consumer grade speaker systems. They are usually reserved for the higher end (read that as much more expensive and full of meaningless verbage) systems.

NachoMahma6 years ago
.  It depends.

.  Rough rules of thumb:
.  The higher the frequency, the less the need for a vented design. Many tweeters and mid-ranges are in their own sealed compartment(s) even if the cabinet is vented for bass.
.  The lower the power, the less the need for a vented design. You're not moving/compressing as much air.
I've found little gaps in almost every pair of headphones I've taken apart.