[LAD] Determining Phase

[Jörn Nettingsmeier]

On 06/26/2011 05:47 PM, Arnold Krille wrote:
> On Sunday 26 June 2011 11:58:54 Jörn Nettingsmeier wrote:
>> On 06/26/2011 10:50 AM, pshirkey at boosthardware.com wrote:
>>>> Other than that, I'd make a really cool spectrum analyzer that ran the
>>>> Fourier analysis on two channels, correlated their phases then made a
>>>> +/- line vs. frequency for all to see so that the phase of the
>>>> components of the spectrum could be watched for phase relationships.
>> that is precisely what dual-fft tools for p.a. system calibration do,
>> and they're extremely useful.
>> they allow you to constantly monitor the system with _program_ material,
>> without having to use MLS noise or any other specific measurement signal.
>> one channel is used for the direct signal from the mixer, the other is
>> fed by a measurement microphone with delay compensation. you get instant
>> phase and amplitude response. good systems also give you an additional
>> "confidence" curve that tells you how much you can trust which parts of
>> the spectrum. for instance, if your program material is a boy soprano,
>> the confidence of the measurement in the low end is practically zero.
>
> I use(d) japa for this :-) Altough that lacks phase display...

it will do the job nicely in its difference setting, but you have to 
find (and compensate for) the delay manually, like a real man.
modern p.a. tools allow sissies like yours truly to just click on the 
"find delay" button and be done :-D