I think you may have been a bit confused. "Standard" inerior doors are hollow--either wood or MDF--even those with nice moulded panels.

Solid core doors from Masonite (or other manufacturers) are another thing entirely. They're three-four times heavier than hollow doors of the same size; they feel substantial and are great for reducing interior noise. I'm a builder and they are the standard in virtually all new custom homes that aspire to quality. I put them in my own home and wouldn't ever use anything else.

Of course, you have to decide whether they're worth the price. If I were specing an average price home here--say $500,000-$700,000--I might go cheap.

Masonite's solid core are kind of solid. They used to have some sort of particle board. I believe they've changed it to some other kind of particle but call it dor-core or something like that. They also make the same doors in hollow (without the 'core').

With MDF doors, they are usually a solid piece of MDF board (resin based) which a pattern is cnc cut out of. IMO, a cut out MDF door is a superior product to a 'solid core' masonite door. last I checked, MDF doors usually are approximately 250 to 350 a door.

Masonite solid core doors use a form of particle board. I haven't used (or seen any comparative studies) on the other solid core doors--all of which also use forms of recycled wood materials, so I don't know which might perform better.

I took delivery on a bunch of Safe and Sound doors yesterday. Prices were: 32"x80", C$100.10; 30"x80", C$97.11; 26"x80" C$91.28--all prices about double those of the hollow core versions I'm using for the closets.

Generally a solid wood door is about 100-120lbs. A 'solid core' masonite door is about 50lbs. A mdf door made by trustile or bolection is about 110lbbs so the heft gives it a real wood door feel. (7ft - 1 3/4"). Mass generally helps with sound as well so you can draw your own conclusions there.

Masonite doors (the interior ones) in the past could not be mortised out. Not sure that is still the case, but I don't think that has changed. It isn't often that one needs to mortise an interior door, but it does give you an idea of the interior strength of the door.

I chose solid doors for the room entrance and hollow core for the closets.

OK people!...here's what I do know (to coin a phrase). We are using solid core 8 foot tall doors from Jeld-Wen "ProCore Quiet Door". They are VERY heavy and solid and we love them (don't get your finger caught in one when closing!). I know I cannot lift a 2/0 8/0 unit by myself easily. So, what is the construction of this door b/c it is quite enough!

The Jeld-web does make solid wood doors which are good and give wood performance. The pro-core Quiet door is their door that competes on the same level as masonite. It's just a molded door with particle board inside to give it a bit more sound transmission and weight. Still nowhere near a real door in terms of weight or an mdf door. It's about half.

If you want to know what a real solid wood door is, just go feel the weight of a solid mohogany exterior door by jeldwen or others. The rest like masonite, pro-core, etc are just cheap substitutes for a real wood door. If your doors are going to be painted, then you can substitute cnc machined mdf doors (like from bolection doors or trustile, etc) as they don't 'move' because of humidity changes and look/feel just as good.

Is the jeldwen quiet door as good as an mdf exterior door for soundproofing a theater door? Would a solid wood exterior door work even better?

I'm looking at 2 panel raised solid core door. The "carrera" and "cambridge" name came up a few times by Jeld-Wen or CraftMaster or MMI (Home Depot). Are all these the same identical door? Or is one better than the other???

I read that Jeld-Wen recently acquired CraftMaster and MMI... so I believe the parent company is the same. But my question, which is the best door?

"Jeld-Wen or CraftMaster or MMI"

All virtually the same, masonite or hardboard moulded doors. Meddle of the road qualilty. In my opinion it comes down more to the millwork shop that hangs the doors and the quailty of the jambs.