I’ve read multiple times that true low budget/no budget Indie film makers never have 5.1 sound on their finished films. .. tell me ... in general terms HOW much more difficult and HOW much more expensive is it?
First, you have to change the way that you think about sound.
There are four discrete audio post disciplines - dialog editing (we'll include ADR recording & editing here), Foley performance & recording, sound effects, and rerecording or mixing.
DX editing and sound FX can all be done is small audio editing suites. Foley is usually done on a Foley "stage." Rerecording or mixing is, at least at the budgeted level, done in a room the replicates a movie theatre.
Here's a Foley stage:
Foley pits:
Rerecording stage at Skywalker Sound:
What you will notice first, I'm sure, is the size of the facilities. Now add in the expense of sonically isolating them from the outside world, and then add in the expense of making them sonically balanced. At Skywalker and similar facilities the speaker systems alone will run up to $250,000. On large budget films the sound track can run up to (and sometimes over) 1,000 audio tracks. So there will most probably be four or five full blown Pro Tools systems; figure another $250,000. Now add another $250,000 for the console.... I'm sure that you get the idea. Building and maintaining a facility like this is
EXPENSIVE, not to mention the extraordinarily talented personnel.
Now, having impressed you with the mega-budget way of thinking, there are lots of smaller facilities that can do 5.1 surround. The issue is "translate-ability," or how the mix will translate in different venues and, eventually, different consumer systems - everything from high-priced home theaters to lap tops. These smaller facilities are often not certified by Dolby. At this juncture it's all up to the talents of the rerecording mixer(s).
Now, as to how all this applies to smaller budget indie films... If you budget about $50k for audio post you could do a very nice surround mix. Most indie films are going to be relatively "simple" films in terms of audio. They probably are not going to have enormous track counts, they probably don't have an incredible amount of special visual effects that need to be supported by sound effects, they probably won't have a score performed by a full orchestra, etc. So everything can be done on a shoestring. A small but talented audio post crew can do all of the DX editing and sound FX editing, there are smaller Foley houses that do nice work on a budget, and you can mix at a non-certified facility. However, the nature of most indie films does not require a 5.1 surround mix, a 3.0 mix will do just fine - dialog and the bulk of the Foley in the center speaker, sound effects and score in the left and right speakers.
Now, I can do all of the audio post on a feature film - I've done seven (7) features, more shorts than I can remember, animated shorts, some corporate stuff, web series pilots, etc. I'm "bargain basement" audio post, specializing in low/no/mini/micro budget projects. Yet I am still beyond the means of many indie filmmakers - they don't budget for audio post and consider anything over $100 for audio post an outrageous expense. They don't budget the
time for audio post. No matter what the level - micro budget indie to mega-budget "Hollywood" production - it still requires a lot of time to do audio editing. It takes me approximately six (6) hours per linear minute to do audio post. So for a 100 minute feature that's 600 hours of audio post work. Even at minimum wage ($7.25/hr) that almost $4,500. And, trust me, I charge more than minimum wage, but a hell of a lot less than the $150 to $500 per hour that bigger facilities charge; that's $90,000 to $300,000 for audio post. Most indie types have already blown their wad before they ask me for a quote. So, it
is cost that defeats most indie films from doing a 5.1 surround mix.
You may want to read the following thread by APE (AudioPostExpert/Greg). It explains in detail what goes into audio post, and I'm sure that he'll chime in with more about why most indie types forego 5.1.
http://www.indietalk.com/showthread.php?t=45351
BTW, your comment about inexpensive 4k digital cameras is a bit disingenuous; the camera may be relatively inexpensive, but now figure in the cost of the lenses and the lighting that will bring the most out of the camera. And what about the talent of the DoP and camera operator? Just because you have a a nice camera does not guarantee beautiful cinematography.