View Full Version : 4th order, 5th orde,r 6th order Filters, What does it Mean ? ?
LE15-Thumper
04-15-2005, 09:46 PM
4th order, 5th order, 6th order Filters, What does it Mean ? ?
Slope per octave ?
And Giskard talks a lot about group delay. Is this just phase shift within a certain band of frequencies ? If you have a lot of group delay for instance from a bass filter/booster such as the BX63. How does this anomily show up in the sound, What do you hear that is undesireable ? What does group delay sound like ?
aust-ted
04-16-2005, 01:13 AM
My understanding of the filter order relates to the # of effective elements in the filter. A simple cap filter is regarded as a first order and is 6dB/ octave. If you add a inductor you have a second order filter (ie two active elements) and you get 12dB/ octave. Can get more complex than this but that is how I think of it, so a sixth order would have 6 active elements and would be 36dB/ octave.
Group delay relates to phase distortion. I find the terminology confusing. The following webpage has a detailed explanation of it -http://www.trueaudio.com/post_010.htm
Regards
Ted
rek50
04-16-2005, 09:43 AM
http://www.the12volt.com/caraudio/crosscalc.asp Some explanations here and calcs to boot.
Dougie
04-16-2005, 12:54 PM
Here is a great link with great graphics that explain crossover slopes and what they mean.
http://www.bcae1.com/xoorder.htm
Doug
4313B
04-16-2005, 01:05 PM
Gotta love the net!
YEAH BABY! :nutz:
Remember having to actually walk to the Library 20 miles one way in hip high snow uphill both ways to get any information at all? :banghead:
Mr. Widget
04-16-2005, 01:22 PM
And Giskard talks a lot about group delay. Is this just phase shift within a certain band of frequencies ? If you have a lot of group delay for instance from a bass filter/booster such as the BX63. How does this anomily show up in the sound, What do you hear that is undesireable ? What does group delay sound like ?
What does group delay sound like? That is a good question. I have never done an experiment to isolate group delay and make a comparison, and in fact doubt that it would have been possible to do prior to the digital age. With a DEQX unit it would be possible to listen to a low frequency system both with and without group delay correction... it would be an interesting comparison and I might give that a shot when time permits.
Without having done the above comparison I can only report on the subjective listening quality of systems with more or less group delay. Since other variables have also been changed I am not certain that this is the correct representation, but to me systems with excessive group delay tend to have less control, sound boomier, exhibit poor transient response etc.
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