> Any multi-band EQ beyond two bands - e.g, other than simple high > boost/cut and/or low boost/cut designs - must, by definition, be > parametric.
Not quite. From a user point of view, there are two types of multi-band equalizers -- graphic, and parametric. A graphic equalizer has filters that have a fixed bandwidth and are fixed in frequency. The only user control is to change the amount of boost or cut within that band. The TX and RX equalizers in the K3 are graphic equalizers. A parametric equalizer has filters that can be varied in frequency, bandwidth, and amount of boost or cut. A shelving equalizer is one that transitions from flat response in the midrange to either boost or cut (usually cut) on the low end and/or the high end. In that "cut" region" the response is also flat, thus the name "shelf." The transition from flat to boost or cut is a gradual one, the shape of that transition and the degree of boost or cut can be varied by design of the analog circuit or the DSP that simulates the analog circuit, and that shape affects the sound quality. A high pass or low pass filter differs from a shelving equalizer in that it is only capable of cutting (rolling off) the response above or below the desired frequency limit, and that there is no intentional "shelf" -- that is, the gain in the cut region keeps dropping as you move away from from the frequency limit. All of these types of equalizers can be implemented with analog components, or in DSP that simulates those analog components. The K3 uses high pass and low pass filters and shelving EQ, implemented in DSP, to limit the bandwidth of the system. In the audio world, most products called parametric equalizers also include high pass, low pass, and shelving functionality. Nowadays, virtually all modern products are implemented in DSP. Before the days of DSP, parametric equalizers were used, but graphic equalizers (mostly 10 bands or 27 bands) dominated the market because they were easier to understand, and easier to set without getting into trouble. DSP and modern instrumentation (and display of the response) changed all that -- every filter burns processing power, so a 27-band equalizer required 5 times the DSP of a 5 band parametric, and the modern instrumentation/display made it easier to see what you were doing with the equalizer. TXEQ and RXEQ in the K3 is a well thought out compromise between processing power and simplicity of use that does almost anything an intelligent user might need. 73, Jim Brown K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
