ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 2 [3]  All   Go Down

Author Topic: Definition of Phase (of a system)?  (Read 11110 times)

Jerome Malsack

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 1395
Re: Definition of Phase (of a system)?
« Reply #20 on: November 06, 2013, 11:21:10 AM »

The phase issue is easy to see when designing a 3 way passive crossover.  The mid range will have a difference in phase based on the pass band of the two segments making up the pass band filter.  Compared with the single elements for a  high pass or low pass filter used for the other two speakers. 
Logged

John Roberts {JR}

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 16903
  • Hickory, Mississippi, USA
    • Resotune
Re: Definition of Phase (of a system)?
« Reply #21 on: November 06, 2013, 12:00:44 PM »

I deleted a longer post about phase, polarity, and delay in the context of loudspeaker crossovers. Mating the sound output from two drivers together in typical loudspeakers is at best is an imperfect exercise. Use of phase shift, polarity flips, and delay (when available) are mainly to prevent very audible suck-outs from deep cancellation. For a while the odd order crossovers were popular because 3 dB bumps were less bad, than deep notches. (but crossover performance also involves off axis lobing, and total spectral energy delivered into the room, etc).

In the context of crossovers a polarity flip "could" improve mating in the crossover region, while resulting in entire bandpasses being opposite polarity from each other. (I am not making a statement about the audibility of that, for some situations apparently a lesser evil).   

Try not to think about this too much (i don't). This is why I defer to the speaker design engineers to design speakers. Crossover design is IMO part of speaker design. Back in the old days I actually designed and sold rack mount analog crossovers, but those were simpler times. Now we have better solutions available.

JR
Logged
Cancel the "cancel culture". Do not participate in mob hatred.

David Gunness

  • Classic LAB
  • Newbie
  • *
  • Offline Offline
  • Posts: 9
    • Fulcrum Acoustic
Re: Definition of Phase (of a system)?
« Reply #22 on: November 08, 2013, 04:51:25 PM »

- Phase response is a description of system behavior.
- Polarity inversion is an operation.
- It can't be proved that a given phase response is due to a particular operation.

David Gunness
Logged
David Gunness
Fulcrum Acoustic, LLC

ProSoundWeb Community

Re: Definition of Phase (of a system)?
« Reply #22 on: November 08, 2013, 04:51:25 PM »


Pages: 1 2 [3]  All   Go Up
 



Site Hosted By Ashdown Technologies, Inc.

Page created in 0.025 seconds with 20 queries.