I sympathize with the effort to make MP3 encoding as simple and as painless as possible, but I also think it's pretty important to understand the encoding process and what it is doing to your sound. The reality is that MP3 encoding will have some level of impact on the quality of the sound, period. Given that, it doesn't make any sense to me that a guy that would spend hours and hours monkeying with various compressor plug-ins and settings, judging the subtle qualities of each tiny change would then blindly mash the final product through a meat-grinder MP3 conversion process where any such subtleties are utterly lost.
Another thing to consider is that there are different contexts for your output. Maybe you're producing stuff for your band to listen to only and don't really care about file sizes and want just the highest quality you can get. Or maybe you're deploying to a site like Reverb Nation where keeping the file size under the free-service limit while ensuring decent qualit is important. Or maybe you're producing downloads for sale and you need to leverage ID3 tags so that end users get the fullest experience possible.
So yeah, let's leverage tools that helps make encoding easy to use but it makes a lot of sense to me to invest a little time in understanding what's happening when you encode. That's why I applaud mudgel's efforts to shed some light on this subject.
One thing I often do is use Sonar to render everything to a WAV file and do MP3 conversions later outside of Sonar. I do this because some encoding scenarios require different bitrates because of file size limitations, or because I want to encode groups of files for an album-style distribution using ID3 tags for track ID's and to assure similar quality settings across tracks. Achieving this level of flexibility is certainly possible with all of the options presented in this thread but for me it's just much easier to open up a command window and do it the old-fashioned way. However you choose to do it, understanding the quality settings are important.
So for those of you who want better control of the encoding process, this is a short summary of the recommendations for the LAME encoder that I pulled from the help docs and massaged a bit to make it somewhat less geeky:
There are three basic ways to encode an MP3 file with LAME:
• Constant Bitrate: CBR encoding is the basic encoding mode of MP3. The bitrate is kept constant across the entire file, which means the same number of bits is allocated to encode each second of audio, resulting in a predictable file size for a given duration. CBR is useful for people who are concerned about maintaining maximum compatibility, especially with certain streaming applications and some hardware-based decoders that don't reliably support VBR.
• Variable Bitrate (VBR mode): The user chooses a desired quality level instead of a bitrate. The encoder will change the bitrate to a higher or lower one whenever the audio file is more or less complex. The main advantage of using VBR is that the encoder will use the smallest amount of bytes needed to keep the asked quality. The inconvenience is that the file size is quite unpredictable, and can change from file to file in more than 50kbps.
• Variable Bitrate (ABR mode): ABR is a mix between CBR and VBR. ABR encoding is desirable for users who want the general benefits of VBR (an optimum bitrate from frame to frame) but with a relatively predictable file size like they would get with constant bitrate (CBR), and a greater preference for bitrates that are near a desired target.
Recommendations for quality:
Best quality, "archiving": CBR 320 is the strongest setting for MP3, with the lowest risk of artifacts. Sample Sonar External Encoder Utility command line:
lame -b320 %I %O
However, with the exception of a few situations, quality is rarely better than the highest VBR quality profiles described below.
• High quality, HiFi, home or quiet listening : -V0 (avg. 245 kbps) or -V1 (avg. 225 kbps) or -V2 (avg. 190 kbps) or -V3 (avg. 175 kbps). These settings are considered to produce transparent encoding (transparent = most people can't distinguish the MP3 from the original in an ABX blind test). Audible differences between these presets exist, but are rare.
• Portable, background noise and low bitrate requirement, small sizes : -V4 (avg. 160 kbps) or -V5 (avg. 130 kbps) or -V6 (avg. 115 kbps) -V6 produces an "acceptable" quality, while -V4 should be close to perceptual transparency.
• Very low bitrate, small sizes, eg. for voice, radio, mono encoding : --abr 80 (stereo) or --abr 56 -m m (mono) For very low bitrates, up to 100kbps, ABR is most often the best solution.
Sample Sonar External Encoder Utility command line:
lame -V0 %I %O
Sorry to be so verbose and I hope someone finds this useful.