  Subjective speech quality assessment is the gold standard for evaluating
speech enhancement processing and telecommunication systems. The commonly used
standard ITU-T Rec. P.800 defines how to measure speech quality in lab
environments, and ITU-T Rec.~P.808 extended it for crowdsourcing. ITU-T Rec.
P.835 extends P.800 to measure the quality of speech in the presence of noise.
ITU-T Rec. P.804 targets the conversation test and introduces perceptual speech
quality dimensions which are measured during the listening phase of the
conversation. The perceptual dimensions are noisiness, coloration,
discontinuity, and loudness. We create a crowdsourcing implementation of a
multi-dimensional subjective test following the scales from P.804 and extend it
to include reverberation, the speech signal, and overall quality. We show the
tool is both accurate and reproducible. The tool has been used in the ICASSP
2023 Speech Signal Improvement challenge and we show the utility of these
speech quality dimensions in this challenge. The tool will be publicly
available as open-source at https://github.com/microsoft/P.808.
