JBL CSS8008 Commercial Series 15-Watt 8" Ceiling Speaker, White 141

Q: if I have 8 of these for a conference room, do I wire them parallel? Also, these show as having 5w transformers, does that mean Id need min 40w amp?

Yes and no... Your amplifier has to be capable of 25v or 70v output, and you just wire them from one to the other, and so on...this is NOT a 4-Ohm/8-Ohm setup with these speakers, you treat them like parallel lighting I wouldn’t put a 40w amp on 8 5w speakers, I’d use at least a 50w or more

Q: are there ceiling tile speakers with volume control

Yes...perhaps as many as there are without volume controls...you could also add the control to any ceiling speaker lacking one. The control is called an L-Pad, which is basically a potentiometer...I checked options and costs online and they can run from $5.00 to $15.00 each.

Q: Do you need the baffle to install this in a ceiling?

My answer would be that it depends on the material that it is hanging from. Whenever this type of speaker is installed on a drop ceiling, you should always install an appropriate metal support frame to prevent the weight of the speaker to cause the ceiling tile to collapse, potentially injuring occupants. If ceiling tiles are exposed to a small water leak they will collapse quickly. If you're going to mount it in a drywall, make sure to use toggle bolts. Any ceiling-mounted speaker should have a back-up cable type of support system in the event that the structure it is mounted to collapses. I have seen situations where water leaks have caused a collapse of a ceiling, and the energizing of wet floor surfaces with 70 volts.