phase and time

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07-07-2005, 09:01 PM

#21

goalie 35

Goalie Man

Join Date: May 2003

Posts: 1,412

in physics time is relative. but it is a constant.

07-08-2005, 03:13 AM

#22

Sassmaster

Merry Christmass from CCA

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Join Date: May 2002

Posts: 2,579

are we not talking about time alignment? Time in a CD recording is not constant, as even the CD can be reversed, replayed, and the information can be stored and replayed at another time, that would be a relative time then. we are not talking about time as an absolute, but as something that can be manipulated with processing.

Time alignment probly has the least effect on the overall sound reproduced. except in creating phase cancellation nodes, or at least moving them.

07-08-2005, 06:01 AM

#23

defro13

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sure time can be manipulated, but what if it isnt manipulated at all with a processor, how then does the affect of phase changing with amplitude affect time

07-08-2005, 12:57 PM

#24

SweetnLow91SC

500 Watt CAFz'r

Join Date: Mar 2005

Posts: 884

Maybe this will clear things up a bit...

Here's a TEF/MLS 3D Spectral Decay waterfall measurement. which shows Time, frequency, Magnitude in relations.

I have TEF/TDS files on Accuwaves in car & Focal TN-51 tweeter which show frequency/phase response, But the computer is in storage.. I could dig it up later.

Name: TEFtestpics1001.jpg
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Size: 28.6 KB

Name: TEFtestpics1001.jpg
Views: 12
Size: 28.6 KB

[ July 08, 2005, 02:59 PM: Message edited by: SweetnLow91SC ]

07-08-2005, 01:49 PM

#25

hobbes26

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Join Date: Oct 2003

Posts: 146

Quote:

Originally posted by beamrider:
boy dave you need a tef analyzer, call up the engineering department at UBC and ask for the director of audio engineering, they have one and a mlyssa analyzer. both of these tools will DEFINITLY do what you want.

tef? Are you sure?

We have MLSSA, and we use it often.

There is no one here with the title "Director of Audio Engineering" as far as I know...

07-08-2005, 09:00 PM

#26

defro13

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so you need to be a director of some sorts to be part of this iscussion

07-08-2005, 10:24 PM

#27

Dereck Waller

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No I think he is saying he is at the UBC and they have no one with that title in the department. I thought MLLSA was a TEF?

07-15-2005, 09:30 AM

#28

SweetnLow91SC

500 Watt CAFz'r

Join Date: Mar 2005

Posts: 884

Quote:

Originally posted by DWVW:
I thought MLLSA was a TEF?

MLSSA & TEF are not related in any way in their technology..... Mlssa uses (Maximum Lenght Sequence)... A special test signal like 1's and 0's that repeat itself periodically. when converted to analog, the Mlssa bitstream creates a pseudo-random noise signal that sounds like white noise. While the TEF uses (Time Delay Spectrometry) A method that permits a spectrum of delayed signal to be measured with the Delay removed... Its achieved by using a pre determined sine sweep test signal then is recieved with tracking filters. TDS measures in the frequency domain, then transforms the results mathematically for interpretation in the energy, frequency or time domains.

The TEF has the Mlssa options..... A while back TEF bought the rights from Mlssa..... so they would have the best of both worlds.

Here is another measurements with the TEF/MLS...

Accuwaves with Altec Lancing CD.(no eq)
Name: TEFRef1a002.jpg
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