phase and time
07-06-2005, 06:47 PM
#1
Guest
Posts: n/a
when we talk about phase adjustment and time alignment what are we talking about. what direct affect does phase adjustment have on time and time adjustment have on phase. both are different but both directly affect one another. for instance when you adjust the phase of a midrange by say 180 degrees, how have you directly affected time. i had a very interesting conversation with someone today and our views were slightly different, got me thinking though
07-06-2005, 07:48 PM
#4
Guest
Posts: n/a
lets think more scientifically, if you adjust time by 1ms, how have you just affected phase in terms of dergrees of phase adjustment. does anyone think that there is a mathematical equation for this. let all just start by agreeing that the 2 affect each other and dispense with that discussion
07-06-2005, 07:55 PM
#5
Goalie Man
Join Date: May 2003
Posts: 1,412
wow very interesting topic dave, if you take a mid and adjust the phase 180 you have now changed its positive phase arrival time at your ear. this could be good or this could be bad, experimenting is always gonna help. what we hope to do by altering phase is to get the 180 degree positive wave, from the drivers, to hit our head at the same time. but we can also alter amplitude as well, as our brain will interpret amplitude as distance. and lastly we can use time alignment to help out one side only in a vehicle. just because all the speakers are in electical phase dosent by anymeans mean that they are in aqustical phase, a sure sign of this, if you have more than two drivers, is a 3db or greater dip or peak on a rta. i would play uncorrelated pink noise on my system at 90 db. then i would get it as close to a 40 as possible. now lets freeze the little red dots and hit print. lets now look at the eq and see what kind of goost or cut we have between bands. boom right away you will see tons of eq at 16 and 20, lots of cut at 200-250 mid boost at 1k to 4k ect. try to change the polarity on one speaker at a time and see if it helps. then go to the next and by the time you are done you will not only be ready to drink 2 dozen beer but you will need to drink 2 dozen beer!!!! cheers.
07-06-2005, 08:16 PM
#8
Guest
Posts: n/a
im not sure that i want to do anything in particular. beamrider im sure that i dont agree with amplitude affecting time or phase, amplitude is amplitude and doesnt affect either phase or time, phase and time are constant, amlitude varies. amplitude can affect bias but not time or phase unless someone can correct me, but i would totally agree that acoustical phase at point of origin and accoustical phase at the point of hearing are very different
07-06-2005, 08:27 PM
#9
Goalie Man
Join Date: May 2003
Posts: 1,412
dave you are right amplitude does not affect phase or time what it can do is trick your mind into beleaving that one speaker is closer than the other.ex. two trains blow there horns on exactly the same horozontal plane, one horn blows at 160 db one blows at 164 db, your mind will think that the second train is closer. i cant believe how bad my spelling is!
