Re: question about speech level (Tony Miller )

Subject: Re: question about speech level
From:    Tony Miller  <antonio.miller@xxxxxxxx>
Date:    Mon, 23 Jul 2012 13:31:43 -0500

Ali- A common approach to your problem is to use the ITU Objective Measurement of Active Speech Level (P.56). Here is a PDF version of the standard: Peter Kabal at McGill University has a nice discussion of the details of the calculations here: "Speech activity measurement involves determining the fraction of time that a signal contains active speech and the speech level while speech is active. Knowledge of the speech activity is important in speech signal measurements. For speech data bases, it is important to ensure that undue leading and trailing non-speech be excised and that the speech level be properly scaled based on the peak signal level and the active speech level [1]. For testing speech coders with environmental noise, artiļ¬cial test signals are created by adding recorded background noise to clean speech segments. The signal-to-noise ratio for such speech-plus-noise signals is determined as the ratio of the active level for the speech to the rms level for the recorded noise." Mike Brookes at Imperial College London provides a MATLAB implementation in his speech processing toolbox (VoiceBox). I hope this helps. -Tony -- Tony Miller Acoustic Systems Group Cirrus Logic, Austin, TX On Mon, Jul 23, 2012 at 4:45 AM, ali fallah <ali.fallah@xxxxxxxx> wrote: > > Dear List > > For creating speech in desired level, I have an AC40 audiometer that produce speech signal in selected dB SPL from a wav file. The recordings has silent periods before and after speech signal. If I delete silent periods before and after the speech signal, the sound intensity that audimeter produce, will not change. Now I want to prepare a mixture of speech and noise in optional SNR values in Matlab but the RMS value of speech signal depends on silent gaps. > > I have two question about this: I want to know for speech signal that is nonstationary, how desired level in dB SPL is set . Also how can I mix speech and noise in Matlab by setting noise in desired value (for example noise level=65dBSPL and SNR=-10 until we have speech in 55 dBSPL). > I will grateful if anyone guide me about this and let me know about related documents. > > best regards

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