HAM RADIO SPEECH RECORDER FULL
HAM RADIO SPEECH RECORDER SERIES

The spectrum of speech covers quite a wide portion of the complete audible frequency spectrum. Average RMS: -21.5 dBFS, Peak: -0.5 dBFS. Male voice, normal speak (duration 18 seconds). This factor is an important parameter when a voice is to be recorded or reproduced in an electroacoustic system.Īlso note: Loud singing, measured at the lips, can reach levels of 130 dB re 20 μPa RMS and peak levels above 150 dB re 20 μPa. The ratio between the peak level and the RMS level is called the crest factor. Typically, the peaks are 20-23 dB above the RMS level. Note that each level presented in the table is an averaged RMS level and not a peak level. There is nearly 20 dB difference between normal speech and shouting. Speech level Listening distance Īverage speech level as a function of listening/recording distance. (In this case, “re” means “with reference to” the reference is the weakest sound pressure level that is audible.) In other words, a sound pressure level of approximately 55-65 dB re 20 μPa. It is worth noting that the ability to understand speech is optimum when the level of the speech corresponds to the level of normal speech at a distance of 1 meter. The values in the table below indicate the average A-weighted speech level of the speech of an adult. It is hard to assign a fixed number to speech level, as this is individual from person to person. Vocal efforts vary from a subdued whisper to loud shouting. At the same time, speech, regarded as an acoustic signal, is the type of sound that we are most familiar with. While language can be something that groups of people have in common, the sound and character of the voice is individual from person to person. The voice as a sound source is important to understand.

HAM RADIO SPEECH RECORDER FULL

When you are ready for a deeper dive into the theory, you should check out the full article below the playlist.

HAM RADIO SPEECH RECORDER SERIES

You can get a quick head start by watching a series of short videos to introduce and explain some important factors that impact intelligibility of the voice. Otherwise be prepared to compensate (equalize) to obtain the correct sound. Be ready to pick the right microphone designed for use in the position you are placing it.

So when placing a microphone be aware of these issues. If the microphone does not compensate for this you should make corrections with an equalizer. This results in reduced speech intelligibility. For instance, the spectrum of speech recorded on the chest of a person normally lacks frequencies in the important range of 2-4 kHz. Standing to the side or behind the person reduces the naturalness and intelligibility.Īctually, the voice chances spectrum in almost any other position than when we approach the speaking person with our ear – or microphone.Įach position on the head or the chest has its’ own sound color – or timbre. We perceive the voice as natural and with the highest intelligibility when we are approximately 1 meter in front of the person talking. More specifically, in the 2 kHz-4 kHz frequency range. The consonants (k, p, s, t, etc.) are predominantly found in the frequency range above 500 Hz. In non-tonal languages the consonants are important. Be sure that all peaks survive through the recording chain. When recording, you will find that the peaks of the acoustical signal are much higher than then the RMS or average level. Shouting sounds different from talking with a casual voice.

Even the pitch of the voice changes with vocal effort. By affecting the cavities above the vocal cords (pharyngeal, oral, nasal), filtering is added to the voice spectrum.Ĭhanging the vocal effort changes both level and frequency spectrum of the voice sound. By controlling the vocal cords the level and the pitch of the voice can vary. So when recording the voice, you should always consider speech intelligibility.Īir passes the vocal cords and creates sound. Read more about what different mic placements does to the voice here.

Ham radio speech recorder