Stereo amplifier vendors generally release the frequency response of their solutions that, sadly, will not necessarily explain to you a lot concerning the sound quality. I am going to shed light on the meaning of this phrase and even provide some suggestions on how to interpret it when looking for an amplifier.
A large frequency response does not always mean the amp provides excellent audio quality. For instance an amplifier with a frequency response between 30 Hz and 15 kHz might sound much better than another amp with a response between 10 Hz and 30 kHz. Also, each manufacturer, it appears, implements a different technique of specifying the minimum and maximum frequency of their amps. The standard convention is to show the frequency range within which the amplification is going to drop no more than 3 dB from the nominal gain.
Yet, a lot of manufacturers dismiss this particular convention. They push the lower frequency and higher frequency to where the amplifier barely offers any gain. On top of that, these numbers tell almost nothing about how linear the amp is operating inside this range. A full frequency response graph, however, will demonstrate whether there are any peaks or valleys and also show how the frequency response is to be interpreted. Peaks along with valleys can result in colorization of the audio. Preferably the amplifier ought to have a constant gain inside the entire frequency response excluding the drop off at the upper and lower limit. In addition to the frequency response, a phase response diagram will also say a whole lot about the functionality in addition to sound quality of the amp.
The frequency response of Class-D amps shows the largest change with different speaker loads because of the integrated lowpass filter which eliminates switching noise from the amplifier's signal. A varying speaker load will impact the filter response to some extent. Usually the lower the loudspeaker impedance the lower the highest frequency of the amplifier. Furthermore, the linearity of the amplifier gain is going to be determined by the load.
A few amplifiers incorporate feedback as a way to compensate for changes in gain caused by different connected loads. A different technique is to offer dedicated outputs for different loudspeaker impedances that are connected to the amplifier power stage by way of audio transformers.
A large frequency response does not always mean the amp provides excellent audio quality. For instance an amplifier with a frequency response between 30 Hz and 15 kHz might sound much better than another amp with a response between 10 Hz and 30 kHz. Also, each manufacturer, it appears, implements a different technique of specifying the minimum and maximum frequency of their amps. The standard convention is to show the frequency range within which the amplification is going to drop no more than 3 dB from the nominal gain.
Yet, a lot of manufacturers dismiss this particular convention. They push the lower frequency and higher frequency to where the amplifier barely offers any gain. On top of that, these numbers tell almost nothing about how linear the amp is operating inside this range. A full frequency response graph, however, will demonstrate whether there are any peaks or valleys and also show how the frequency response is to be interpreted. Peaks along with valleys can result in colorization of the audio. Preferably the amplifier ought to have a constant gain inside the entire frequency response excluding the drop off at the upper and lower limit. In addition to the frequency response, a phase response diagram will also say a whole lot about the functionality in addition to sound quality of the amp.
The frequency response of Class-D amps shows the largest change with different speaker loads because of the integrated lowpass filter which eliminates switching noise from the amplifier's signal. A varying speaker load will impact the filter response to some extent. Usually the lower the loudspeaker impedance the lower the highest frequency of the amplifier. Furthermore, the linearity of the amplifier gain is going to be determined by the load.
A few amplifiers incorporate feedback as a way to compensate for changes in gain caused by different connected loads. A different technique is to offer dedicated outputs for different loudspeaker impedances that are connected to the amplifier power stage by way of audio transformers.
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