First and foremost, you need to decide what kind of recordings you will be primarily using it for. That will often dictate a lot of the key features of what recorder you should consider, assuming that you only want to pay for what you need. However if money is no object, then pick out the top few and draw one out of a hat.
If the bulk of your work is Reality TV, and you are one of the last kids out there still mixing to camera or just a two track, then there are some great options out there for you. If you primarily do Feature Films and Narrative work, your options are going to be more expensive because your line of work is very demanding as far as various services that you are expected to provide on set. If you are a Sound Effects recordist, then you may have a variety of needs depending on what kind of things you record, and how intricate you get. For documentaries, there are also a number of options. Is there a recorder good for all occasions? Yes of course, but it may be out of your price range if you do not really need many of its features. Lets discuss the options.
Feature Films and Narrative work is very demanding on the Sound Dept because it requires a great many things, and naturally we have to provide a ton of very expensive equipment. This is one of the reasons why Sound is among the highest paid people on set; because of the advanced knowledge and experience they need to have on a great many levels, and because they provide a lot of expensive equipment. Some of the things that a Production Mixer for a Narrative will do aside from recording the various audio tracks (Boom, Wireless, Plant mics, etc..) is make a Mix Track. This is an on-the-fly mix that is being recorded as the action is actually happening. This is why we are called Production Mixers, and not just Recordists. Why do we do this? Well it is simple really, because we always have. Before the era of multi-track field recorders, the most you could record were two tracks, and most of Production Audio has been a single mono track from a historical standpoint. So if we have two booms, and three plant mics, we would have to make a usable mix track of all of those elements because there was no option of recording them all individually. We still do this today because it can save the production tons of time and money in Post Production. Another thing that we do is provide Time Code, so the sound and picture are in sync. Later, in Post Production, the Assistant Editor will go through all of the audio and film takes and re sync them so that they both play at the same time. Time Code makes it so that they just snap together, instead of having to look for the Slate marker and line it up manually, which can be very time consuming if you have a lot of takes. We also provide a feed known as IFB so that the Director, Script Supervisor, and possibly others can hear what is happening on set, because some times they cannot all be in the same room, and if they can, they cannot always hear whats going on. We also sometimes send a scratch track to camera to be used for Dailies (so that people can look at the take and have some audio on it to know which is the best take to be used in the edit). We also generate Sound Reports, so that the Assistant Editor and Post Sound Depts can see information of each take, which is very helpful when you have to do a lot of dialogue editing, or the production decided to use a take that was good for camera, but not for sound. Aside from all of these things, you need to have a way to communicate with your Boom Operator and Audio Tech without sending your communications out to all the feeds or onto the recording. So you need a versatile mixer/recorder with a lot of options. Most recorders designed for Narrative work do little in regards to mixing, so you will often see guys with a mixer in front of their recorders.
Reality TV is its own animal, and I can safely say that it was entirely designed to be cheap, but time and technology has made it expensive for us, and productions are having a hard time keeping up with what they need to be paying. Once upon a time, Reality TV was invented mainly because it was an inexpensive way to make a television program. If it takes (hypothetically... these are not real numbers) $800,000 to make one episode of Dexter, you can make an episode of Jersey Shore for $280,000. Smaller crews, no actor's unions (no actors really...), quick turnaround. Originally, a Reality Sound Mixer had a boom and maybe a couple of other mics, and a portable mixer, and he was tethered to the camera via a "break-away cable", which was a cable with various sends and returns, that had a connector in the middle that the camera operator could detach and run off to follow the action while the Sound Mixer could catch up, re attach, and keep going. Then two channel recorders were made available, and they began recording audio as a backup, still recording mainly to camera (this is so they didnt have to re sync audio in post production. Early reality TV was shows like COPS where the sound didnt need to be perfect, so camera audio was fine). These days we can record all the tracks separately, record mix tracks, and have time code so re syncing the audio takes no time at all, as long as the camera has time code as well. The problem today is that we need more expensive and feature rich recorders, we still have to send to camera, but wirelessly now, we need time code accessories, and we need lots of wireless mics. So our costs have gone up, and productions are trying to pay us less than when we basically just provided a mixer, boom, and some cables. You still need to make that on the fly mix to camera though because production is still trying to be cheap and not have to re sync audio or mix it in post, but you dont necessarily have to make detailed sound reports or anything like that. You may still need to send IFB feeds to the producer/director.
Documentary Sound is interesting because technically, you do not need cinema quality sound, as long as you can hear and understand what people are saying. Obviously getting the best sound as possible is the goal, but if you really pay attention to the audio on a lot of documentaries, it is usually pretty bad. This is often because they have the camera person also running the audio instead of raising enough money to pay someone who knows what they are doing and has the proper equipment. Realistically, you can choose any sort of recorder for this type of work, but the more features you get, the more options you have. I suggest getting something designed for Reality TV, because it is meant to be portable, and still feature rich without necessarily making you pay for a bunch of features you wont need. The flip side to that are the big budget documentaries like those that National Geographic and the BBC are famous for making. If you want to make that kind of a product, you need some serious funds, so dont try to do everything yourself.
Sound Effects recordists can often make due with a two channel recorder, but some guys get crazy with how detailed they want to get, and will use up to eight mics just to get a simple sound effect. On the other hand, a lot of these guys also record Surround Sound effects and ambiances, and need a good amount of channels to record to. So you really need to know what exactly it is you are trying to do. When I record sound effects, I try to get a mono version of it, and a stereo version of it. If the project has a real budget, and they plan on releasing a surround sound mix of the film, then recording ambiances and effects in surround is important, and sounds really cool!
Next I will discuss a few popular recorders, and talk about their different features, and pluses and minuses.
Sound Devices 788T
Sound Devices 664
Sound Devices 744T
Sound Devices 722/702/702T
Edirol/Roland R-4 Pro
Hand Held Recorders
So in the end, your needs may not justify getting an eight channel recorder/mixer with all the bells and whistles, but I would like to remind you that with audio, you really get what you pay for. The reason why a two-channel Sound Devices recorder costs over $2,000 and has no built in mics is because of quality and performance. That said, a $400 Zoom recorder has that price point for a reason. To put it so that someone who doesnt know much about sound can understand it, it is like the difference between using a professional cinema camera, and a flip camera... literally! Lower quality parts and manufacturing go into making machines more affordable, and most of the time, the weekend warrior who makes films on no budget may not understand that many of the things out there that they are using to make their films were never intended to be used in that way. A hand held recorder, like I said, was made for taking voice notes and conducting interviews (to later be transcribed and typed), so it is not the same quality as a professional recorder. Things like signal-to-noise ratio, dynamic range, bit depth and sample rates, flexibility with files, metadata, I/O, and more are all things that make one machine better than the other. One can always argue that it is the archer and not the arrow that hits the bulls eye, and many people are able to get good results using cheap equipment. But realistically, if you want to get funding for your film, get into festivals, distribution, or even be taken seriously as a film maker, then you cant be running around with toys.
A lot of people think that an audio dream package for the DSLR crowd is a Zoom H4n, Rode NT-2 shotgun mic with Rode Boom Pole, and a set of cheap headphones. Someone who really knows what they are doing can get adequate results with that setup, but I should remind you that booming and sound in general require years of experience and tons of knowledge to be any good at it, and your product will only be so good if you are using inexpensive "pro-sumer" equipment. An NT-2 microphone is cheap for a reason, and can only capture audio up to a certain amount of quality. A Zoom is also cheap for a reason, and can also only record a certain amount of quality. The combination of the two will never get you award winning sound, even in the hands of a pro. If your recorder has limited dynamic range, what that means is that the difference between the loudest sound it can handle before it distorts and the quietest sound it can handle before it fades into the noise-floor and becomes inaudible is very small. Kind of like if you had a volume knob for your stereo, but it only had three clicks you could choose from instead of variable loudness at any point, so those clicks go from off, to half way, to super loud. Without more "resolution" between those points, your listening experience on your stereo can be very limited, and most of the time wont work because you dont want to disturb your neighbors or damage your speakers. Limited resolution in your recorders dynamic range means that finding a middle ground will be very difficult for recording something like dialogue, which usually doesnt stay the same level, but gets quiet and loud depending upon what is happening in the scene. This means that you can either set your recorder to record loud audio so that it does not clip, but then you lose all the low level stuff because it is too low to be of any use, or you can set your levels to get all that low stuff, but then the recording clips whenever they get a little loud. A professional recorder will have better dynamic range and be able to give you usable audio from each end of the spectrum.
Regarding Sound Effects recording, if you are making recordings for resale, most people want them recorded at a super high sample rate (192 kHz). The reason for this is that sound designers need high quality samples so that they can manipulate them without degrading the audio. In photoshop, you start with a high rez photo, manipulate it, then save it at the desired size. Same thing here. Record a "high rez" recording, manipulate it, and save it at the resolution of the film. Not all recorders can record at this high of a sample rate. Some recorders that normally record eight channels can only record four at this rate, which is pretty common among Analog to Digital converters. But most of the cheap recorders can only record at 44.1 kHz (CD quality) or 48 kHz (film quality). So making a surround (7.1 for example) recording at 192 kHz means that you need a serious machine to pull that off. Classical music is often recorded at a higher resolution too, because people who are interested in what music professionals refer to as "serious music" (classical, opera, jazz, etc) are also often interested in the quality of the audio, and will own expensive home systems with advanced playback feature so that they can absorb the audio as if they are actually there! "HD CDs" and other high definition formats for all types of music and films are also available, but to make one you have to start with a higher sample rate, not just convert your lower sample rate audio to a higher one (you may actually loose quality by doing that!). Usually you can get an album that was originally recorded on tape in a high definition digital format, but a lot of modern music is recorded at a lower resolution (to save space and resources for the computer), so those records will not be able to be made available in high definition, and if they are, they are not truly high definition. A famous singer wanted to release a high-def greatest hits album, but somewhere along the line when he stopped recording to tape, all of his music was recorded in low definition digital, and he couldnt actually do anything about it, so only about half of the guy's music was able to be re released! What a bummer for that guy!
Back to the subject at hand. A recorder is a big investment, and a professional will always own professional equipment. If you are an indie film maker looking for advice for recorders, and have your eye on a Zoom or something like that, my personal advice to you is this: Dont waste your money on a recorder at all unless you plan to make a career out of recording audio. A recorder worth having is going to cost more than your camera, and it is not nearly as easy to get good results with sound as it is to take a pretty picture, especially since you are using a sense that most people dont really explore or train. A Good sound person should have advanced knowledge in electronics, acoustics, computers, how lots of things work (like speakers, tape and tape machines, record players, not to mention EQ, compression, radio and sound waves, frequency spectrums, etc...) the list goes on. Thats why people spend years studying it, then years trying to get good at it. The smartest thing you can do regarding your indie film is to hire a professional sound team to make it happen for you. They have the equipment, knowledge and experience to get you professional results.
When you make a film, you show to the world a lot of things: How professional you are, and how serious your work is to you, and all kinds of things that say a lot to people. When I see an indie short with bad audio, I see someone who didnt take the project (or how the world sees him as a film maker) serious enough to really come up with the money and put the time into it to show the world that they want to be a professional film maker. Even if you make one short film per year, they need to be the best. One amazing film is better than a dozen amateur ones. Quality over quantity is important in this business. If I see that you didnt care about a project, and let obstacles like no funding for your student/passion project, why would I ever want to hire you to make my film? But if I see that you scraped up enough money over x amount of time,saving and saving, and went ahead and made one amazing film, I will see compassion, dedication, taking the job really seriously, and understanding how important every part of the piece is in order to get the best results. You cannot settle for second best when you are trying to show the world what you are capable of. So if you are in fact serious about what you do, I invite you to read my other blog entries, I write a lot about things that indie film makers need to know, and their film schools never told them about!