Audio technology in amateur radio covers the processing, reproduction and quality of the audio signal at the receiving and transmitting end. A good modulation quality results in a good speech intelligibility and a pleasant listening impression, brings more success in DX and more QSOs in contest operation.

Newcomer to ham radio have this aspect understandably less in their focus. Other things are more important like the best possible antenna. And at the beginning one is content with the standard hand microphone and any headphone, which is compatible at least in impedance and connection with the transceiver. The only importance seems to be that the stations on the other end is well understood. And obviously one does not hear their own signal. So if the radio partner does not complain, everything seems to be alright. As long as the controls for mic gain and compression on the transceiver are set correctly, this is usually the case.

However, the quality of the voice transmission also depends to a large extent on the correct speaking distance and the frequency response of the microphone. In earlier times, amateur radio operators placed emphasis on modulation that was as sharp as possible with good speech intelligibility, especially for DX operation. External compressors did the rest.

The signals were loud and assertive. Only up to a certain degree was this an advantage with the right settings. Because the intelligibility quickly turned into the opposite. The modulation had little to no dynamics - which does not sound too pleasant!

The digitization of audio technology and the use of extensive DSP technology, as external equipment or integrated into the transceivers, allow numerous possibilities to influence the audio on the receive and transmit side and to adjust levels and frequency response individually. Since then, a "culture" of pleasant and natural sounding audio has taken hold. This can often be observed in some evening rounds in the 80-m-band, where the participants are almost exclusively concerned with setting their equalizers and modulation quality. Likewise, AM is not dead yet! In the 80- and in the 10-m-band there are AM sessions with stations in almost HiFi quality.

In the days of voice radio in amplitude modulation (AM), it was much easier to produce a natural sounding modulation due to the larger available bandwidth of the signal. Today's problem is to get the best possible speech quality out of the bandwidth limitation of 2.7 kHz or even 2.4 kHz in SSB mode.