On comparing speech quality of various narrow- and wideband speech codecs

In recent years wideband speech coding has attracted quite a lot research. However, there have been only a few papers describing the quality difference between narrow and wideband coded speech. In this paper we describe the testing methodology and how the sample processing was done in order to evaluate these two conditions in a single test. Results from a six different listening tests are shown and explained in detail. In addition to standard AMR wideband and narrowband codecs we have tested two so called open source codecs namely iLBC and Speex. We have no knowledge that these codecs have been tested earlier in a formal listening test.