DiyMobileAudio.com Car Stereo Forum banner
1 - 20 of 70 Posts

·
Registered
Joined
·
419 Posts
Discussion Starter · #1 ·
When doing individual speaker tuning, I know you're supposed to use correlated(mono) PN Pink noise, but is it a good practice to use uncorrelated Pink noise when tuning L&R speaker pairs?

I'm asking this question because of the newest HELIX Software version as it includes some tuning .wav files. Its got a Time alignment.wav file, INPUT Signal Analyzer correlated pink noise .wav file, and has a RTA uncorrelated .wav file. Got me thinking why would they supply just the uncorrelated(stereo) pink noise for RTA......
 

·
Registered
Joined
·
419 Posts
Discussion Starter · #4 ·
Thank you for the link opekone. I'm still a little fuzzy on weather or not I should use uncorrelated pink noise when tuning L&R together. Correlated or uncorrelated pink noise can be used for a single speaker. The link you posted is from 2008, and they were using correlated pink noise mainly for time alignment, and using uncorrelated pink noise to tune a single speaker at a time, but nobody mentions anything about EQ'ing L&R together using uncorrelated.

Audio Frogs USB microphone comes with a tuning CD and tuning instructions. In the tuning instructions, it explains that track 1 on the CD is 15 minutes of correlated (mono) pink noise, and the objective is to use the mono pink noise to tune the left side of your stereo, then tune the right side of your stereo, then match your left side to the right side. But mentions nothing about tuning (EQ'ing) L&R together.

The info in that threat suggest using uncorrelated to tune a single speaker, Audio Frog uses correlated for the whole system,,,, and well now I'm confused.

So, the link you posted sortra implies to use uncorrelated for L&R but is not clear, and the Audio Frog tuning guide uses correlated. Most current tuning practices today suggest to, tune a left speaker, then tune a right speaker, then tune L&R together.

I'm guessing that I should use correlated to tune each speaker individually, then use uncorrelated when tuning L&R together, but I'm just guessing, and would like to know what truly is the best way.
 

·
Registered
Joined
·
19,637 Posts
If you understand the difference between the two, it should be pretty obvious.. When doing one speaker at a time, or even one side at a time, correlated vs uncorrelated is irrelevant. Stick with mono (correlated) though. It shows how the sides interact and will show phase anomalies. Stereo (uncorrelated) is used for certain situations, but its rare.

Sent from my SM-G975U using Tapatalk
 

·
Registered
Joined
·
1,953 Posts
Why are they refered to as "correlated" and "uncorrelated" instead of just "Mono" and "Stereo" to begin with? Just causes more confusion as you have to remember which one equates to "Mono" and which one equates to "Stereo". Everyone is already familiar with "Mono" and "Strereo" - why not just stick with those names? :)

Is there a reason why they just don't use "Mono" and "Stereo"?
 

·
Registered
Joined
·
419 Posts
Discussion Starter · #7 ·
I understand the difference between them. When tuning a single speaker or a entire side, I totally understand it doesn't matter if mono or stereo is used, and I totally understand mono is a good tool to show phase anomalies, I get that.

But after I have fixed my phase probs and tuned each side (or speaker) with mono, I then focus on whole system Overall tonality and Frequency Response (tuning to my Overall House Curve), wouldn't it make sense to use stereo pink noise at this point ??
 
  • Like
Reactions: tfunk182

·
Registered
Joined
·
419 Posts
Discussion Starter · #8 ·
Why are they refered to as "correlated" and "uncorrelated" instead of just "Mono" and "Stereo" to begin with? Just causes more confusion as you have to remember which one equates to "Mono" and which one equates to "Stereo". Everyone is already familiar with "Mono" and "Strereo" - why not just stick with those names? :)

Is there a reason why they just don't use "Mono" and "Stereo"?

I don't know why.... but from now on going forward, i'll use the mono/stereo terms....
 

·
Registered
Joined
·
833 Posts
Why are they refered to as "correlated" and "uncorrelated" instead of just "Mono" and "Stereo" to begin with? Just causes more confusion as you have to remember which one equates to "Mono" and which one equates to "Stereo". Everyone is already familiar with "Mono" and "Strereo" - why not just stick with those names? :)

Is there a reason why they just don't use "Mono" and "Stereo"?
Because that's not what they mean
 

·
Registered
Joined
·
1,953 Posts
I don't know why.... but from now on going forward, i'll use the mono/stereo terms....
My comment wasn't directed at you - I was just curious why some people use "correlated/uncorrelated" and others use "mono/stereo". I see it constantly and it constantly causes confusion for those that aren't familiar with the correlated/uncorrelated names. In the end, someone always ends up having to cross-reference them to mono/stereo anyway. :) Even @SkizeR x-references them above as well.

A lot of times you'll see "Stereo" and "Mono" in parenthesis after uncorrelated and correlated (or vice-versa). Whether or not they technically mean the exact same thing, people eventually have to cross-reference them at some point - so I was just curious why the two different ways are used to identify the same thing - or if there was some technical reason why - that's all.
 

·
Registered
Joined
·
419 Posts
Discussion Starter · #11 ·


Welp, I found the answer I was looking for. Hanatsu posted this on post #153 in the above thread. >>

"Uncorrelated noise for full system frequency response measurements.

Correlated noise to tune T/A and L/R EQ by ear.

Using MLS or Swept Sine (Avilable in ARTA and RoomEQ/REW) you can get much more data than using noise / pink noise. You can even T/A by looking at the impulse response. "
 

·
Registered
Joined
·
419 Posts
Discussion Starter · #12 ·


Welp, I found the answer I was looking for. Hanatsu posted this on post #153 in the above thread. >>

"Uncorrelated noise for full system frequency response measurements.

Correlated noise to tune T/A and L/R EQ by ear.

Using MLS or Swept Sine (Avilable in ARTA and RoomEQ/REW) you can get much more data than using noise / pink noise. You can even T/A by looking at the impulse response. "

and this post is for jtrosky>>

"STEREO noise for full system frequency response measurements.

MONO noise to tune T/A and L/R EQ by ear.

Using MLS or Swept Sine (Avilable in ARTA and RoomEQ/REW) you can get much more data than using noise / pink noise. You can even T/A by looking at the impulse response. "
 

·
Registered
Joined
·
833 Posts
The pink noise is either phase aligned or phase random, it's either correlated or uncorrelated. How you route that signal is up to you. Don't you think it's confusing to play a stereo file mono or play a mono file stereo?
 

·
Registered
Joined
·
833 Posts
Uncorrelated and Correlated noise files are both stereo. The interesting distinction is that in one case the two channels are in phase and in the other they are both in a random state. If the only thing that means to you is mono and stereo then sure, great.
 

·
Registered
Joined
·
419 Posts
Discussion Starter · #17 · (Edited)
If you play a phase random file through 1 channel, its mono. If you play a phase random file through 2 channels (L&R) its stereo.
If you play a phase aligned file through 1 channel, its mono. If you play a phase aligned file through 2 channels (L&R) its mono.
 

·
Registered
2015 BMW i3
Joined
·
180 Posts
Uncorrelated and Correlated noise files are both stereo. In one case the two channels are in phase and in the other they are both in a random state. If the only thing that means to you is mono and stereo then sure. Great.
So in the case where they are in phase, there are different signals being sent to left & right? Or they are the same signal, of which there are 2 channels?
 

·
Registered
Joined
·
833 Posts
You can answer that yourself. They are labeled to describe the significant and interesting difference between them. If the best way you can describe that is with stereo and mono, then run with it brother.
 

·
Registered
Joined
·
1,953 Posts
and this post is for jtrosky>>

"STEREO noise for full system frequency response measurements.

MONO noise to tune T/A and L/R EQ by ear.

Using MLS or Swept Sine (Avilable in ARTA and RoomEQ/REW) you can get much more data than using noise / pink noise. You can even T/A by looking at the impulse response. "
Honestly, I don't use different pink noise files for tuning different parts of the system. I use the same pink noise file for everything - single speaker, speaker pairs, whole sides and overall system EQ measurements - I use the Kicker "20 min Lab Grade Pink Noise" file that is hosted on the Kicker site (https://www.kicker.com/files/test_tones/Lab_Grade_Pink_Noise_20_minutes.wav) - they only offer one type of pink noise file - it's 2-channel, but the left and right channels are exactly the same - which I'd consider mono pink noise. I've been using that same .wav file since I first started tuning and it works well for me. It does show phase issues when measuring multiple speakers together.

I've never used true Stereo pink noise (2 channels with different content in each channel) for any tuning (right or wrong).

I think it's safe to say that when someone says "Mono Pink Noise", they are referring to correlated pink noise and when someone says "Stereo Pink Noise", they are referring to "Uncorrelated Pink Noise"....
 
1 - 20 of 70 Posts
Top