Always by the end of a compositional project I am in doubt how to transfer all my material from 32 to 16bits. I understand that if I want to chop 16bits off my samples this will/may lead to ‘damage’. This is what Reaper tells me to help making a choice: “In (very) brief, when you render from a higher bit depth to a lower one, you lose some resolution, and the lost resolution leaves low-level artifacts in the resulting signal. Dither is a way of blanketing the artifacts with more natural-sounding low-level hiss. Noise shaping is a way of filtering the artifacts into parts of the frequency spectrum that are harder for human ears to (psychoacoustically) perceive.

Some people think you should always dither when rendering to a lower fixed-point bit depth. Other people think that dither doesn’t exist. The first people and the second people like to argue with each other. (*shrug*) There are lots of discussions out there on the internet about whether or not to dither and when to do it and why. This post isn’t meant to do that — it’s just to explain technically what Reaper does if you click the buttons.

  • The dither and noise shaping are independent (you can use either with or without the other).
  • The dither is 1.5 bits which is somewhat on the light/do-no-harm side. With noise shaping off, the dither PDF is triangular; with noise shaping on, the dither is high-pass filtered.
  • The noise shaping is a 9th order filter, which is similar to pow-R type 3.
  • Unlike pow-R (or almost any other method), the noise shaping coefficients are calculated on the fly for any sample rate analytically, based on a very smooth equal loudness contour.
  • The render dialog should only give you the option to dither when the target bit depth and format is appropriate. The calculation is done post-master-fader, so you don’t need to do anything special except click the buttons.
  • There are a few JS dither plugins included with Reaper. These are for technical use or backwards compatibility. You don’t need to use them. Definitely don’t use any dither plugin if you’re using the native dither options when rendering.

The dither and noise shaping options in Reaper are of very high quality.

But I’ve decided to take a listen myself, before going ahead. I have rendered three different parts of the composition, each with a different setting (dither, noise shaping and D & NS combined). I mean, it’s all about what you actually hear, isn’t it? The Reaper people themselves are more rock-oriented, which makes things a little easier for them.