Here´s an update to my mentioned problems:
I´m still not able to get a decent rendering from Reaper into mp3, but I have found a work around which works for me, and which I like to share with you:
I´m using the FLAC Codec (http://flac.sourceforge.net/) which is a lossless audio format to rip my classical music CD´s so I can listen to them on my PC in great quality as well.
By chance I found out, that Reaper can render into this format as well and - oh wonder! - this time the audio file generated sounds exactly the same in my flac-player (I use this one:
http://www.foobar2000.org/) as I heard it on my monitors/Headphone.
Foobar2000 offers the option to convert a *.flac file into another audio format (with some options to tweak).
When converting from flac to mp3 I notice two things:
-) The tonal difference between lossless and compressed audio format
-) The big difference in file size - also in comparison to Reaper rendering into mp3. (Reaper mp3: 1,2 to 1,8 MB; Flac: 6-9 MB; Flac Converted MP3: 600 - 900KB)
But the great thing is that by this way I don´t loose too much of the original tone while generating/converting a mp3 file of my recording.
I´m really happy with this procedere and maybe some of you can give me feedback if it works for you as well?!
Just wanted to let you know!
Cheers
Berglmir
Flac is certainly a better format than mp3 because it is uncompressed.
Wave is uncompressed and is nominally CDA (CD Audio) and for most purposes is often your best choice since not all devices - inclusing DAWs - can read Flac but pretty much all can read wave. You should use render etc settings for wave that are appropriate for your playback and storage medium. Nominally CD is 16 bit 44.1. Most DAWS run at 24 bit fixed or 32 bit float and the SR can be set usually anywhere from 44.1 to 196 (and some go up to 392). You can use 96 - and higher - but most consumer grade audio cards, playback and and speakers do not merit going above 96k - many only offer 44.1 and/or 48. IMHO for SR unless you have good SRCs then you are probably best staying with 44.1. 44.1 is standard for CDs and 48k is the standard for broadcast.
There is a big advantage going from 16 to 24 bit fixed but very little in using 32 float. 16 to 24 will improve the nominal noise floor from @-96 dB to -144dB for recording and a nominal dynamic range of 144 dB is more than enough for tracking/mixing/recording. The vast majority of hardware audio devices - including most sound cards - run at 24 fixed . If you use 32 bit then either the DAW or your sound device will have to truncate or dither the file and they may not do it particularly well. If you do use a 32 bit float file/preference setting in your DAW then you should check how it does the truncation/dithering. Also you should try and only ever dither
once and since dithering is best left as the last stage for mastering a finished recording it is nearly always best not to dither whilst you track/mix/record. If you're not mastering/having your audio mastered then you should apply dither as the final stage for the render and you should consider what dither type you use and whether or not you apply noise shaping.
Mp3 quality can depend on the encoder you use to convert the file. By default Reaper uses LAME. LAME has been through a number of updates and some versions do not do the conversion particularly well. So you may want to try a different mp3 encoder. You might also want to only use the 320 kbps setting.
Two other things:
1 - if you're audio file prior to conversion is close to clipping, over say -0.4, then LAME will often clip it as it gains the buss by up to 0.5dB and you can end up with a digitally distorted/hard clipped audio recording.
2- many mp3 encoders do a LPF at about 15k. This often can make the recording sound like it has lost sparkle/air.