Sunday, April 6, 2014

Uncovering The Truth About Recent Music Amplifiers

By Marta McBrian


The frequency response is just about the most frequently found parameter to characterize stereo amplifiers. However, it might often be deceptive and might not really offer a good indication of the sound quality. I am going to clarify the meaning of this expression and even give some recommendations on how to interpret it whilst searching for an amplifier.

An amplifier is able to only work inside of a specific frequency range. Any kind of signals outside of this range will be removed. Therefore the frequency response gives an essential hint regarding whether or not a particular amplifier may be well suited for a particular application. Normally a lower and upper frequency are shown, for example 20 Hz - 20 kHz. This kind of spec indicates that the amplifier can amplify music within this frequency range. You may be thinking the greater the frequency response the higher quality the amp. That, on the other hand, might not always be the case. You should glance at the specs much more meticulously in order to adequately interpret these.

Then again, various manufacturers push this standard to the limit and tend to show an upper frequency where the amplifier is going to barely create a signal any more. Furthermore, simply taking a look at these 2 figures doesn't say a lot about the linearity of the frequency response. Therefore it is best to possess a full frequency response graph. This sort of chart is going to reveal if there are any kind of considerable peaks or valleys within the working frequency range. Peaks and valleys can cause colorization of the audio. If at all possible the gain of the amplifier needs to be linear through the entire operating range. In order to better understand the frequency response behavior of a certain type, you should try to figure out under which conditions the response was determined. You'll find these details in the data sheet of the amp. Then again, a lot of manufacturers will not publish these in which case you ought to get in touch with the producer directly. One condition which can impact the frequency response is the impedance of the speaker connected to the amp. Typical loudspeaker impedances vary from 2 to 16 Ohms. The lower the speaker impedance the higher the load for the amp.

The circumstances under which the frequency response was measured are also important to fully understand. One condition that may effect the frequency response is the impedance of the loudspeaker attached to the amp. Typical loudspeaker impedances range between 2 to 16 Ohms. The lower the speaker impedance the higher the strain for the amplifier. This change is most detectable with most digital amplifiers, also referred to as Class-D amplifiers. Class-D amps employ a lowpass filter within their output in order to reduce the switching components which are generated through the internal power FETs. Yet, the frequency response of the amplifier now is determined by the loudspeaker load since the behavior of this lowpass filter is influenced by the load impedance. Commonly the lower the loudspeaker load impedance the lower the upper cut-off frequency of the amplifier

A number of the latest digital amps feed back the audio signal following the lowpass filter to be able to compensate for this tradeoff and also to make the frequency response of the amp independent of the attached load. Then again, if the amplifier is not designed well, this sort of feedback might cause instability and also result in loud noise being created by the amplifier if specific loudspeakers are attached. Other amps employ transformers and offer outputs for various speaker loads. In addition to enhancing the frequency response of the amplifier, this approach typically furthermore improves the amplifier efficiency.




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