Home Theater Forum - View Single Post

Mark Hayenga · 12-30-2003, 07:24 PM

Group delay is just the negative derivative of the phase plot. Phase changes coincide with frequency response variations, and the more rapidly the frequency response changes the more phase shift you'll get. Higher order systems have more rapidly changing frequency responses, so you get bigger phase shifts where the response starts to roll off, and higher group delay.

I think dipoles still terminate at 12dB/octave (it should since you've still got a basic mass-spring-damper 2nd order system), so theoretically it's not a lot better than a sealed box (a low Q dipole will be better than a midQ sealed box, but a highQ dipole will be worse than a midQ sealed box). I think the main benefit of dipoles is that the side lobe cancellation helps to prevent room mode excitation.

I think I'm more or less correct, but someone call bullshit on me if I'm wrong.

12-30-2003, 07:24 PM	#9 of 13
Mark Hayenga Member Join Date: Jun 1999 Local Time: 08:03 AM Local Date: 12-02-2008 Posts: 854	Group delay is just the negative derivative of the phase plot. Phase changes coincide with frequency response variations, and the more rapidly the frequency response changes the more phase shift you'll get. Higher order systems have more rapidly changing frequency responses, so you get bigger phase shifts where the response starts to roll off, and higher group delay. I think dipoles still terminate at 12dB/octave (it should since you've still got a basic mass-spring-damper 2nd order system), so theoretically it's not a lot better than a sealed box (a low Q dipole will be better than a midQ sealed box, but a highQ dipole will be worse than a midQ sealed box). I think the main benefit of dipoles is that the side lobe cancellation helps to prevent room mode excitation. I think I'm more or less correct, but someone call bullshit on me if I'm wrong. "There are 10 types of people in the world: those that understand binary, and those that have friends."