Sure I get pink noise is flat tonally to our ears...whereas white is equal in energy....
But I don't get what either pink or white noise have to do with FFT.
FFT can analyze either type noise, and show results in either pink or white space.
I see FFT as simply a math method to translate amplitude in the time domain to frequency domain.
Pink doesn't show as a tilted response on FFT software, because it knows the stimulus is pink.
White and pink are just different energy spectrum...I can't see how that has anything to do with how FFT works???
Maybe I'm missing something?
I refer to it as the 1/3rd octave scaling.....it may still be fft, I'm not sure what the scaling is on the "other" common metering. White noise does not show as a linear response if the scaling is set to 1/3rd octave. If the scaling is not 1/3rd octave, then pink noise will not show as linear. They are both fft style measurement I think but I am not certain.
Hi Camplo, in the classes I've taken to try to learn about FFT, scaling normally refers to the frequency axis, whether it is linear or logarithmic.
And if logarithmic, whether marked by decade, octave, or 1/3 octave.
(I'm thinking this is of the kin you are talking about. ?)
So scaling really only refers to how frequency axis is laid out.
How the frequency data is grouped on that axis, whether by octave, 1/3 octave, 1/6th, ...1/48th is termed 'banding'.
The data can even be 'unbanded' where it shows as a line graph...just like a normal frequency response curve.
So, you can see FFT doesn't really have anything to do with a particular way of displaying data, or what type signal stimulus was used to obtain the data.
(The same data is used by FFT to generate mag, phase, impulse, RTA, spectrograph...etc etc.)
One can say if one measures in octaves, 1/3 octaves (or whatever has a constant RELATIVE bandwidth - which sounds even to our hearing) one has to be aware that the ABSOLUTE measurement bandwidth is increasing with measured frequency range. Therefore white noise with its constant density would show an increasing response if measured that way.
OTOH discrete Fourier transform uses frequency steps of a constant width, which in turn asks for a stimulus with linear density versus frequency. This constant frequency steps are the reason why the DFT Fourier transform based systems show a very coarse Resolution at the lower frequencies and a very high one at the higher frequencies as soon as the data is displayed on a logarithmic frequency axis BTW.
Regards
Charles
OTOH discrete Fourier transform uses frequency steps of a constant width, which in turn asks for a stimulus with linear density versus frequency. This constant frequency steps are the reason why the DFT Fourier transform based systems show a very coarse Resolution at the lower frequencies and a very high one at the higher frequencies as soon as the data is displayed on a logarithmic frequency axis BTW.
Regards
Charles
Oh, one more thing worth mentioning .....
rather than using a single FFT at a single sample rate,
good modern FFT's can use a series of sample rate decimations and varying FFT sizes, all stitched together to overcome the time vs freq trade-off.
For example, Smaart claims to achieve 1 Hz resolution at low frequencies with only 1/20th the number data points compared to a regular 32K FFT.
SMAART is designed for live sound environments. they dont sell low latency DSP processors. and most systems have their own dsp avalible. the user just gets to piggyback on the dsp to get the overall system sounding good.
its designed to quickly get best effort mesurements which can help you get a good enough tune on whatever you are using, master channel eq, lake processor, 31 band etc.
also designed for continuous monitoring during performances, so its easy to chase down feedback etc.
its not for ultra high res mesurements in controlled environemtns like REW
This was a nice pre-amp back in the day (had the original greenish version with a 405 and later a dark gray version with 606 power amp).
The tone controls were among the best ever implemented in a consumer audio product.
It would be pretty useless for a horn loaded loudspeaker system though, unless the XO is passive.
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Those look solid, with a sturdy flange.
The throat reminds me of the K-Horn (spherical):
The throat reminds me of the K-Horn (spherical):
An externally hosted image should be here but it was not working when we last tested it.
And here's another spherical horn, also of German descent:
An externally hosted image should be here but it was not working when we last tested it.
Never the less high frequencies when available to be reproduced seem to influence the
lower frequencies we can hear. Two articles here discuss the importance of NOT cutting
frequencies off abruptly: It's Alive! Ultrasonic Spectra Isn't So Ultra Anymore
The World Beyond 20kHz
And just for fun, a small part of the studio of a producer/DJ that uses several spherical horn loudspeakers as monitors (from the same German brand as the loudspeaker in my previous post). One smaller monitor is visible on the left, with a reversed red bongo on top.
Vilallobos?!