# White Noise VS Pink Noise. What we tune with and why?



## SkizeR (Apr 19, 2011)

Having a convo with a few friends talking about frequency response and it eventually turned into a convo on tuning said frequency response and how. "well measured with pink noise then fine tune by ear of course".. one friend then said, in laymens terms, "but pink noise isnt flat". then we were like "oh **** your right. why the hell do we tune with pink noise then?" 

which brings me to... why the hell dont we tune with white noise instead of pink noise if white noise is acoustically flat, while pink noise is a downward slope? 

like lets say im tuning via mic and rew and im using pink noise and i tune it to have a desired curve. once i play an acoustically/recorded flat signal (like music?), im not going to have that desired curve. im going to that curve that is heavily weighted and sloping upwards, no?


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## sqnut (Dec 24, 2009)

Says so on the description of the different noises. Our hearing is logarithmic so although white noise measures flat we would perceive one octave up twice as loud so 800 would be perceived twice as loud as 400. With oink noise there's equal power between each octave so we perceive it equally loud but it measures a downward slope. At least that's how I've always thought about it.


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## SkizeR (Apr 19, 2011)

sqnut said:


> Says so on the description of the different noises. Our hearing is logarithmic so although white noise measures flat we would perceive one octave up twice as loud so 800 would be perceived twice as loud. With oink noise there's equal power between each octave so we perceive it equally loud but it measures a downward slope. At least that's how I've always thought about it.


wouldnt this would be how our ears hear. not a perfect downward slope like pink noise?


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## SPLEclipse (Aug 17, 2012)

There's a difference between how we hear (the psychoacoustic response graph) and the logarithmic scale of power required to produce the same relative _acoustic energy_ at each frequency (which is what pink noise is).


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## SkizeR (Apr 19, 2011)

SPLEclipse said:


> There's a difference between how we hear (the psychoacoustic response graph) and the logarithmic scale of power required to produce the same relative _acoustic energy_ at each frequency (which is what pink noise is).


*sigh*.. cant believe i (we) completely overlooked this lol


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## Justin Zazzi (May 28, 2012)

The tools we use (real time analyzers) have a flat response to pink noise, not white noise. If they had a flat response to white noise, we would use that instead. It has nothing to do with our hearing or pyschoacoustics.


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## BlackHHR (May 12, 2013)

Correlated and uncorrelated pink noise is also another subject that has been brought up.


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## SkizeR (Apr 19, 2011)

BlackHHR said:


> Correlated and uncorrelated pink noise is also another subject that has been brought up.


well outside of stereo vs mono.. im curious as to why we tune with pink noise signal vs white noise signal. SPLEclipse answer makes sense. so does jazzi's. hmmm


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## BlackHHR (May 12, 2013)

Nailed it ^^


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## SkizeR (Apr 19, 2011)

BlackHHR said:


> Nailed it ^^


Who specifically? 

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## jtaudioacc (Apr 6, 2010)

Jazzi said:


> The tools we use (real time analyzers) have a flat response to pink noise, not white noise. If they had a flat response to white noise, we would use that instead. It has nothing to do with our hearing or pyschoacoustics.


but the RTA is only something Fred Flinstone used back in Bedrock. if you're still using an RTA, you must be Barney Rubble. :laugh::laugh:


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## SkizeR (Apr 19, 2011)

jtaudioacc said:


> but the RTA is only something Fred Flinstone used back in Bedrock. if you're still using an RTA, you must be Barney Rubble.


You talking about the rta used to judge? Or all rta's, like rew

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## Niick (Jun 3, 2015)

SkizeR said:


> Having a convo with a few friends talking about frequency response and it eventually turned into a convo on tuning said frequency response and how. "well measured with pink noise then fine tune by ear of course".. one friend then said, in laymens terms, "but pink noise isnt flat". then we were like "oh **** your right. why the hell do we tune with pink noise then?"
> 
> which brings me to... why the hell dont we tune with white noise instead of pink noise if white noise is acoustically flat, while pink noise is a downward slope?
> 
> like lets say im tuning via mic and rew and im using pink noise and i tune it to have a desired curve. once i play an acoustically/recorded flat signal (like music?), im not going to have that desired curve. im going to that curve that is heavily weighted and sloping upwards, no?


if you look at pink noise on a raw FFT analyzer, it slopes downward. White noise is flat horizontally.

If you then engage octave or fractional octave banding, pink noise becomes flat on the screen, and white noise will slope upwards. 

The reason pink noise is used for ACOUSTIC testing has a lot to do with the amount of HF content (energy) being more closely related to the way the speakers will be excited while in real world use (music) 

If you use white noise for acoustic testing (exciting loudspeakers) the HF energy content would be way higher, which would potentially over drive the tweeters.

White noise IS often used for ELECTRONIC testing.


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## Justin Zazzi (May 28, 2012)

jtaudioacc said:


> but the RTA is only something Fred Flinstone used back in Bedrock. if you're still using an RTA, you must be Barney Rubble. :laugh::laugh:


RTA works the same as most acoustic analyzers do, off of bandwidth-limited bins that have equal energy per bin (or per octave). For more reading, see below:

Pink Noise Versus White Noise


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## Woosey (Feb 2, 2011)

Jazzi said:


> The tools we use (real time analyzers) have a flat response to pink noise, not white noise. If they had a flat response to white noise, we would use that instead. It has nothing to do with our hearing or pyschoacoustics.


Exactly! And on an rta pink is flat, on an fft analyzer white is..


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## SkizeR (Apr 19, 2011)

Woosey said:


> Exactly! And on an rta pink is flat, on an fft analyzer white is..


difference between you and jazzi is that you suck at explaining things lol


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## Rrrrolla (Nov 13, 2008)

If you were to generate noise in a linear scale, you would be generating as many "spikes" of energy between 10khz and 20khz as you would between 0hz and 10khz. The amount of energy "heard" in the highest octave would be equal to that of the 7 lower octaves. This is what we hear when we off tune our radios to static, and it sounds like there is very little bass, just a high frequency hiss. Pink noise makes as many "spikes" of energy between each octave on average, so it sounds more balanced to us since our hearing frequency resolution is MUCH better at lower frequencies. The spikes aren't necessarily higher (although it can be done that way), there is just more of them, thinking in terms of a linear scale.


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## Niick (Jun 3, 2015)

jtaudioacc said:


> but the RTA is only something Fred Flinstone used back in Bedrock. if you're still using an RTA, you must be Barney Rubble. :laugh::laugh:


Yabba Dabba Dooo!!


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## Woosey (Feb 2, 2011)

Jazzi said:


> The tools we use (real time analyzers) have a flat response to pink noise, not white noise. If they had a flat response to white noise, we would use that instead. It has nothing to do with our hearing or pyschoacoustics.





Rrrrolla said:


> If you were to generate noise in a linear scale, you would be generating as many "spikes" of energy between 10khz and 20khz as you would between 0hz and 10khz. The amount of energy "heard" in the highest octave would be equal to that of the 7 lower octaves. This is what we hear when we off tune our radios to static, and it sounds like there is very little bass, just a high frequency hiss. Pink noise makes as many "spikes" of energy between each octave on average, so it sounds more balanced to us since our hearing frequency resolution is MUCH better at lower frequencies. The spikes aren't necessarily higher (although it can be done that way), there is just more of them, thinking in terms of a linear scale.




Does this mean we also must change the scale if using the rta function?


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## Woosey (Feb 2, 2011)

SkizeR said:


> difference between you and jazzi is that you suck at explaining things lol


It's a German thing.. Lol..





No I only live there lol


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## Rrrrolla (Nov 13, 2008)

Woosey said:


> Does this mean we also must change the scale if using the rta function?


I would think most RTA's use a log scale. It wouldn't make much sense to use pink noise with a linear frequency scale. All your data would be crammed to the left.


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## Niick (Jun 3, 2015)

I posted this recently in another thread. Top graph is pink noise on a linear scale, raw data, unbanded
Bottom graph is pink noise on a log scale, 1/6 octave banded









for acoustic spectrum analysis, you want log scale, fractional octave banded...so, like, 1/3, 1/6, 1/12 etc.

I tend to use acoustic transfer function, log scale, fractional octave smoothing.


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## Woosey (Feb 2, 2011)

Niick said:


> I posted this recently in another thread. Top graph is pink noise on a linear scale, raw data, unbanded
> Bottom graph is pink noise on a log scale, 1/6 octave banded
> 
> 
> ...


I was more thinking this way..


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## Bayboy (Dec 29, 2010)

I once tried using brown noise to tune and it turned out like crap!


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## susedan (Aug 11, 2015)

Bayboy said:


> I once tried using brown noise to tune and it turned out like crap!



Did the brown note sound like ****?


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## Woosey (Feb 2, 2011)

Bayboy said:


> I once tried using brown noise to tune and it turned out like crap!


Lmfao!


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## oabeieo (Feb 22, 2015)

Woosey said:


> It's a German thing..lol



verstehe


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