|
Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
|
|
|
Propeller Head Plaza Technical and scientific discussion of amps, cables and other topics. |
|
In Reply to: Perhaps A Different Idea On DBT's? posted by thetubeguy1954 on June 5, 2006 at 10:34:54:
When I listen subjectively, frequency extremes and transparency is NOT what I am listening for. Instead I focus on dimensionality, soundstage width & depth or what some might call "air around the instruments". These things, at least from my experience, do not vary greatly with sound level changes, nor have I ever been ever to equalize these traits into a system via an equalizer if it doesn't already possess them.You may already be aware of this, but just to make sure, I'll mention it anyway. In analog devices like amps, preamps and speakers, the frequency response defines more than just how much the device emphasizes or suppresses notes of different pitch. If you change the magnitude of the response vs frequency (say, in dB), the phase vs frequency must change also. Further, for devices having negligible distortion, there's a mathematical relationship between the frequency response (of which both magnitude and phase must be known) and the transient response of the device. So if you change the frequency response, the transient response is also affected. This means that the way the device responds to the attack and decay of a transient must change. It's not known exactly how this correlates to perception, but it's not at all unreasonable to expect that it could affect perception in some of the ways you mention.
Equalizers are mainly designed to "fix up" amplitude response, and they generally ignore phase. So there's a possibility that they could make the magnitude of the response better, but degrade the phase response. This in turn could possibly degrade the transient response.
Now there are some kinds of systems, such as the DRC package (digital room correction) in which both the amplitude and phase of the frequency response are measured and corrected (via a microphone at the listener's position). An example of the before measurements (in red) and after (in blue) are shown here . Notice how the "before" data doesn't really look like a step at all at the very start of the waveform. It goes up for an instant like it should, then goes negative, then back positive again with some ringing. The corrected trace below it in blue is still far from perfect, but you can see at the start that it behaves much more closely to an ideal step than the uncorrected data. It turns out that the DRC is actually correcting for the non-ideal phase characteristics of the loudspeaker crossover network.
So to sum up, frequency response necessarily includes both magnitude and phase, which are inseparable and together determine transient response. This relationship means that frequency response variations could cause other issues besides emphasizing or suppressing notes of a given pitch.
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: Perhaps A Different Idea On DBT's? - andy_c 06/6/0611:31:31 06/6/06 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
