When should I use single precision or double precision filters?

Document created by BrettG Employee on Sep 26, 2011
Version 1Show Document
  • View in full screen mode
SigmaStudio allows me to use either single-precision or double precision for most filters in the library. When should I use single and when should I use double?

 

The SigmaStudio help document recommends that you use  double-precision for filters with cutoff frequencies near or below 10%  of the sample rate, or when the Q is very high.

 

There is a brief technical explanation of the differences here:

http://www.earlevel.com/main/2003/02/28/biquads/

 

This  is a very good document describing fixed/floating and single/double  architectures and the advantages/disadvantages of each:

http://www.rane.com/note157.html

 

Basically,  for a single-precision filter in the SigmaDSP, you use 28 bits for the  coefficient storage, whereas the double-precision version uses 56 bits.

 

In  most general purpose fixed point DSPs, the bit depth is lower  (like 16 bits in Blackfin), so double-precision is the norm for most  audio filters, regardless of cutoff frequency or Q.

 

This FAQ was generated from the following discussion: When should I use single precision or double precision filters?

Attachments

    Outcomes