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Author Topic: "Pink Noise" Re-EQing - opinions please!  (Read 322 times)

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Offline Pittylabelle

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"Pink Noise" Re-EQing - opinions please!
« on: December 06, 2017, 03:14:31 PM »
Hello,

I would like to hear your opinions please!

I've been researching the topic Re-EQ of my audience recordings for some time now.

Until recently, I did not edit my recordings EQ-technically and in principle always left RAR. If necessary, only an increase of the volume or a channel adjustment came into question.

It was always clear to me that I could improve the sound of a recording by correcting the EQ. But I was just too insecure to screw around by ear at the EQ - virtually without "scientific control".
Of course, I make sure all RAR recordings of my concerts have a backup, only edited versions came to a "release" but, as said before, without EQ post.

On the internet I came up with the idea to apply the EQ of a "Pink Noise" to the recording.

Short for the term "Pink Noise":
"1/f noise, also known as pink noise, is a noise that decreases with increasing frequency. In acoustics, 1/f noise is perceived as a noise in which an average person perceives all frequency ranges of the audible sound spectrum as roughly equal. "

Accordingly, "Pink Noise" should be regarded as an idealized frequency response - just without musical content. ;-)

With the iZotope RX program, I can generate a track with as many seconds as I can "Pink Noise". If you look at the frequency spectrum of such a "track", you find that it is very linear and balanced. Most of the professionally mixed or officially released pieces that I've examined to this effect have followed a frequency response close to this "pink noise" line.

Secondary topic: The current trend in the field of mixing even goes so far that the audio track of each instrument is turned down so far that it just disappears behind the "Pink Noise" or is no longer audible - the finished mix sounds very balanced.

OK, back to the topic: If I now apply the EQ of "Pink Noise" to 100 % on my track, the song begins to sound really good. If I then look at the new frequency spectrum, it comes damn close to the idealizing course. It is much, much more balanced and also the "gaps" were somehow "ironed out".

As a comparative example, I took a piece from one of my audience shots:

Simon Phillips's Protocol IV - 2017 11 11 Muenster DE - 03 Pentangle.flac
Simon Phillips's Protocol IV - 2017 11 11 Muenster DE - 03 Pentangle - Pink Noise.flac

https://drive.google.com/drive/folders/1SPsbjk5Kal3pOTGfqSeb8fMYiByYSggf?usp=sharing

Once untreated and once with "Pink Noise" EQ match. Please see also the corresponding EQ screen shots.

I would be happy if one or the other here in the forum listen to the times or could compare it.

Cheers!
« Last Edit: December 06, 2017, 03:29:03 PM by Pittylabelle »
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Offline Gutbucket

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #1 on: December 06, 2017, 05:56:36 PM »
What you seem to be doing is automatically adjusting the frequency response of your recording, averaged over some period of time, to match the frequency response of pink-noise averaged over time.

Whatever software you are using to do this analyzes your recording and determines the average frequency response curve for it.  It does the same to find an average frequency response curve for the pink noise source you are using as a target response.  It then adjusts the frequency response of the recording to match that of the target.


Pros and cons-
The potential advantage of something like this is that you don't need to trust your monitoring system and your own hearing skills to make the decision about what EQ adjustment to make.  The downside is that you are not using your own hearing skills to determine what EQ adjustments are most appropriate.

Pinknoise not always going to be the most appropriate average response shape for all music.  Yet it's probably closer to optimal than a lot of uncorrected live recordings.  As EQ mistakes go, you can mess things up far more by adjusting things by ear without good monitoring or being careful about what you are doing, whereas you probably can't really screw things up too badly using this technique, even if it doesn't do as good a job as a skilled listener could do listening through a well calibrated monitoring system.


How it might be used more effectively-
Not sure what software you are using to do this, and there are several which provide this functionality now, but all of them essentially do the same thing- you specify a file to be adjusted, and another file as the desired target response you wish to apply to the first.  You are currently using pinknoise as the target response.  Instead, you can try using a really good sounding recording of very similar music to your recording you wish to adjust.
 
The instrumentation and spectral content of your recording and the target should be similar.  If you try to automatically EQ match a reggae recording with a great sounding flute solo piece, you'll probably be disappointed with the results.  Similarly if you tried to automatically EQ a solo violin recording to pink noise, it would be trying to add way more bass than would be appropriate.

It will probably work best with recordings that have full-spectrum content (think full bands rather than soloists), especially if you are using pinknoise as a target rather than similar music.

I suspect the target music should probably also be similarly recorded- that is to say if you are adjusting your live bluegrass recording, use a really good sounding live bluegrass recording with similar instrumentation.  It may not work as well to use a studio bluegrass recording, but that's just a speculation.   

Try matching to a recording of similar music which you really like the sound of.  Then compare the original, the one matched to pink noise, and the one matched to the other recording.


The hand waving-
I know how these things work but have never actually used any of them myself.  A lot of studio guys will dismiss this kind of automatic EQ matching and rightfully so- not all music is the same and a pair of well trained ears connected to someone who knows what they are doing sitting in front of a well-calibrated monitoring system can do a better job.  However, something like this may be the best option for tapers who don't want to have to worry if they are making correct EQ decisions, especially if the response of their playback system isn't trustworthy, which is going to be most of us. 

The thing only tapers will care about-
Note what you are doing in the recording txt file so other tapers will be aware and won't try to use your recording to judge the raw sound of the microphones or something.
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Offline EmRR

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #2 on: December 06, 2017, 07:19:27 PM »
I honestly don't like this idea.  I'm a studio guy, and an equipment repair tech.  I spend a lot of time looking at spectral analysis of both music and equipment response.  I've never seen music naturally look like pink noise, or white noise, be it produced music or live capture.  As one example, music played in a key will exhibit obvious dominant frequencies corresponding to the notes in the key, with lesser amounts around the unplayed notes of the key.   The place it's most likely to look similar is a long time window - the length of an entire song or show.  The place it won't is a short time window, a portion of a song, and that's the one that matters most perceptually.  I do agree with many of Gutbucket's points.
« Last Edit: December 06, 2017, 10:33:49 PM by EmRR »

Offline Pittylabelle

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #3 on: December 07, 2017, 06:16:38 PM »
Thanks to you both, and in particular to Gutbucket for these very interesting and detailed points.

I really appreciate that. :cheers:
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Offline Pittylabelle

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #4 on: December 07, 2017, 06:22:39 PM »
BTW, about my example of the drummer Simon Phillips - this sad news reached me today: :(

Crap! Apparently Simon and his fiance lost everything
in one of the California wildfires ... Please donate if you can!

https://www.gofundme.com/jwequ-life-rebuilding-fund?pc=tw_dn_cpgntopnavlarge_r&rcid=r01-151267968091-96247761c4fc4b22
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Offline bombdiggity

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #5 on: December 07, 2017, 10:53:22 PM »
I've never seen music naturally look like pink noise, or white noise, be it produced music or live capture.  As one example, music played in a key will exhibit obvious dominant frequencies corresponding to the notes in the key, with lesser amounts around the unplayed notes of the key.   

That.  I don't really think smoothing it all out provides a natural result. 

GB's observations are as usual on point and thoughtful as well. 

Listening to your samples just briefly on internal laptop computer speakers (not a high end playback system) the result is what I'd expect from the description of the process and the graphs.  A very strong mid range but not much bass response or fullness.  I lean a bit toward midrange/clarity but were I working on this material I'd definitely end up somewhere between these two.  The original is solid but could be enhanced.  I'd not go nearly as far as the pink noise eq doing that. 

I agree what you play back on is important but a more universal approach whereever the playback is to focus more on clarity and relative balance than forcing a particular sound signature (which is what a pink noise sort of eq approach does).  How well you can hear each element of the ensemble and how well they are balanced relative to each other can be roughly assessed on any reasonable playback system, though a really bad one may provide an inaccurate picture of the balance. 
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Offline EmRR

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #6 on: December 08, 2017, 01:24:48 PM »
The other place I see this (alarming to me, as an audio engineer) trend is in audiophile playback world, people 'de-mastering' commercial releases as if horrendous decisions are always made by the professionals and artists who signed off on the released version of a mix.  In that case, yes, it's a given that many pop recordings have too much dynamics processing added to achieve 'loudness', removing any sense of dynamics from the recording, and on very sensitive dynamic playback systems that processing is really hard to listen to; it sounds faulty.  To alleviate that with EQ alone is impossible, and you generally can't undo dynamic range reduction.  That is a particular world where people don't so much listen to music as they listen to playback systems, with their listening habits formed around what sounds good on their system versus being purely musically based. 

At any rate, I encourage people to make mistakes with equalizers.  It's the only way you'll learn what can/can't/should/shouldn't be done.  Listen to your results on as many systems as you can, note the differences.  Try again.    You'll end up with a better result than any automatic shortcut process will ever bring.  More practice brings greater awareness of all the tricks that can be done to salvage a bad recording, or polish a great one, including knowing when to leave well enough alone. 

Offline Gutbucket

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #7 on: December 08, 2017, 04:25:43 PM »
audiophile playback world

^ Banished their own tone controls in the name of "purity" yet now are "re-mastering experts".  Somewhat ironic, no?

Yet, it's important to recognize the larger particularities of the live music taper world, and the inertias within it.  Most tapers are not audio engineers, nor mastering engineers, yet release their recordings for others to enjoy.  There exists in the taper world a sense of "documentation purity" which is more fallacious in many ways than audiophile banishment of tone controls - the belief that what is in a raw recording is somehow a pure, objective representation of "how it really sounded there".  Is not the choice of mics (not to mention how one sets them up and where) inseparable from the sound of the resulting recording?  Which of several recordings is the objective truth? 

Still, the not-uncommon taper fear of fucking up the recording by making bad EQ choices isn't misplaced and is a good reason for not doing anything to "improve things" without the confidence that one is doing more good than harm.

Sure, careful listening and good EQ choices are the best answer for achieving higher quality recordings.  I also suggest tapers teach themselves to use EQ appropriately and learn when to trust and when not to trust what they are hearing.   But many will never commit to that, for whatever reason, and "somewhat better" if still "less than perfect" is going to be a vast improvement for the majority of amateur live recordings.   For better or for worse, we are our own mastering engineers.

Used wisely, this technology has potential to improve the majority of live tapes.  Yeah, pink noise does not equate to an average music response.  But at least it is a known linear response which isn't horribly off.   Since it's linear you can dial in your own tilt-EQ to counter it pretty easily, or a specific curve more to your liking.  It's not like loudness-war squashed dynamics.

For most folks who just want something that is somewhat more listenable without much extra work this may be an appropriate option.  Again, like everything in life, when used wisely. 

Morally, it's really not so very different than choosing to use a different set of mics.  Choices.
« Last Edit: December 08, 2017, 04:27:23 PM by Gutbucket »
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Offline EmRR

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Re: "Pink Noise" Re-EQing - opinions please!
« Reply #8 on: December 08, 2017, 06:14:52 PM »
There exists in the taper world a sense of "documentation purity" which is more fallacious in many ways than audiophile banishment of tone controls - the belief that what is in a raw recording is somehow a pure, objective representation of "how it really sounded there".  Is not the choice of mics (not to mention how one sets them up and where) inseparable from the sound of the resulting recording?  Which of several recordings is the objective truth? 

Yeah, everything is a tone control, and should be recognized as such.  If they weren't, I could get by with only a few mics, but I have around 70.  More mics and the time to select the right one, or a larger and larger flown array recording multiple mic and pattern options allowing one to pick the best, and EQ the least.  No audio recording or photograph is truth, so pick the best method at hand, learn as many skills as you can, that'll improve the odds of picking the best method, etc etc.  Obviously I'm looking at this from an engineers perspective, not being in the taper pit myself. 

Personally I'd rather hear the untouched 'pure' recording that I can manipulate if needed, versus the 1/f processed version that can't be undone.  If someone is gonna 1/f process, then make both available.   

Something like 1/f processing may someday come to be viewed like auto-tuned vocals in production music.  Some of the broadcast multi-band processors probably shoot for 1/f shapes (at least one is a 31 band limiter) which is about maximum broadcast coverage (radius distance from tower) for licensed FCC broadcast power, it's not about sound quality.

 

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