tape hiss / digital silence... auditory "bias"?

[dubrichie]

alrighty,

could the widely held "belief" that tape (and indeed analog anything in general, but primarily tape) sounds "better" than digital be understood as tape hiss (or similar analog HF noise) acting upon us like some sort of "bias" signal?

it occurred to me a while ago when tracking an acoustic tune with a band all live in the room together. i left the mics on the lead guitar amp open and recorded them as extra room mics as it was not being used on this number.

when i forwarded these channels i found it very nice to have the amp hiss in the mix. i kept it low, but it's there and it's nice. you don't notice it, but it seems to add "air" to the mix, to "lift" it somehow. i won't say that it added "dimension", more that it seemed to enhance it.

so, what about that tape hiss then?

could it be "biasing" our auditory system in some way?

[Zep Dude]

Originally Posted by dubrichie

alrighty,

could the widely held "belief" that tape (and indeed analog anything in general, but primarily tape) sounds "better" than digital be understood as tape hiss (or similar analog HF noise) acting upon us like some sort of "bias" signal?

it occurred to me a while ago when tracking an acoustic tune with a band all live in the room together. i left the mics on the lead guitar amp open and recorded them as extra room mics as it was not being used on this number.

when i forwarded these channels i found it very nice to have the amp hiss in the mix. i kept it low, but it's there and it's nice. you don't notice it, but it seems to add "air" to the mix, to "lift" it somehow. i won't say that it added "dimension", more that it seemed to enhance it.

so, what about that tape hiss then?

could it be "biasing" our auditory system in some way?

It's one piece of the equation. There's also compression, softening of the highs, saturation not to mention the additional iron in the transformer based units like the Ampex's.

[MarkRB]

Originally Posted by dubrichie

alrighty,

could the widely held "belief" that tape (and indeed analog anything in general, but primarily tape) sounds "better" than digital be understood as tape hiss (or similar analog HF noise) acting upon us like some sort of "bias" signal?

it occurred to me a while ago when tracking an acoustic tune with a band all live in the room together. i left the mics on the lead guitar amp open and recorded them as extra room mics as it was not being used on this number.

when i forwarded these channels i found it very nice to have the amp hiss in the mix. i kept it low, but it's there and it's nice. you don't notice it, but it seems to add "air" to the mix, to "lift" it somehow. i won't say that it added "dimension", more that it seemed to enhance it.

so, what about that tape hiss then?

could it be "biasing" our auditory system in some way?

If they were all in the same room it probably gave some depth/spill that you wouldn't of heard with the mics closed.

[joelpatterson]

We'll know if this is a dangerous line of inquiry if this thread suddenly and mysteriously vanishes....

[wheever]

I would totally believe that it acts on us psychoacoustically, somehow.

Complete silence is just unnatural, and most environmental sounds (wind, rain, water) contain white (or pink or blue) noise. White noise tends to be soothing...Hm.

But here's a further thought: would *digital* white noise have the same (notional) effect?

[Kiwiburger]

Digital white noise, as I understand it, is pure random numbers - and as such, it creates what I believe Paul Frindle would call "illegal" samples.

My understanding of what this means is that any audio waveform is - by virtue of acoustics and air pressure - a smooth, continuously varying waveform. At no point does a real analog waveform drop out or jump to an extreme value - it has to conform to the laws of physics.

A random computer generated white noise can create data that is "illegal" - in other words, could not possibly be re-created by the D/A converter. The D/A converter does it's best to create a smooth, continously varying waveform that best matches the data it is being given. The two are not the same, which is the basis for a lot of misunderstanding about digital audio.

So my guess is that analog white noise is much better than digital white noise, because it is inherently "legal". Digital white noise, i'm guessing, would probably add to the complications of illegal data - especially inter-sample peaks.

[joelpatterson]

But then, when it comes time to make music for robots, your whole theory will go out the window.

[rackdude]

white noise shouldn't just be change varying at all or random at all. By definition it should have the exact same amount of power at each frequency, right? That would basically make it sound so perfect that it would be, well, digital sounding... but, I bet you could work with it, send it through your da and through a preamp and back, and now you should have a analog colored noise... isn't that what tape hiss is?

[nightscope]

Originally Posted by joelpatterson

We'll know if this is a dangerous line of inquiry if this thread suddenly and mysteriously vanishes....

Ha!! Indeed.

I was listening to JT's "Fire and Rain" in the car the other day. Loads of tape hiss. Must be the rain. Kinda cute.

ns

[wheever]

Originally Posted by joelpatterson

But then, when it comes time to make music for robots, your whole theory will go out the window.

Ha! I removed my robot's transducers because the criticized my mixes for sounding "too analog"! As further punishment I left them out in the rain. That'll learn 'em! The rat robot bastids!

[nightscope]

Originally Posted by rackdude

analog colored noise... isn't that what tape hiss is?

No. ACN is a totally different thing. Although there are plugins that will convert analogue colored noise to tape hiss.

Actually, if you're experienced enough you can even see tape hiss. It's a sort of like a muddy colored fog and sparkles when the lights are dimmed. Not everyone can see it.

ns

[vernier]

Only hiss I ever heard is at the beginning of one of the songs on the first Crosby Stills & Nash album ...sounds nice actually.

[Unclenny]

Kind of like audible dithering?

[wheever]

Originally Posted by nightscope

No. ACN is a totally different thing. Although there are plugins that will convert analogue colored noise to tape hiss.

Actually, if you're experienced enough you can even see tape hiss. It's a sort of like a muddy colored fog and sparkles when the lights are dimmed. Not everyone can see it.
ns

Yeah, right now in VT there's a lot of white noise in the air. Make driving difficult.

I used my laser white noise-to-tape hiss converter on it, and now there's iron oxide flakes all over everything. They had to come by and plow it.

[dbbubba]

Wow.... the memory of what analog hiss actually sounds like has faded from common memory!

It's like the approximately 18 year-old "child toy" girl that I overheard talking to the middle-aged couple that she was with at a trendy restaurant in Hollywood (I can only guess why she was there.)
She was asking about the "fabulous" era of the '70s when I heard her ask the the couple, "Was everything finer in the '70s?"

Me and a couple of other Gearslutters overheard the conversation and laughed and laughed later!

Yeah, everything WAS finer in the '70s.
Everything was immensely thinner and sharper edged.
Nothing was wider than a few thousands of an inch.

[RKrizman]

Originally Posted by dubrichie

so, what about that tape hiss then?

could it be "biasing" our auditory system in some way?

I love that idea.

-R

[Sigma]

Originally Posted by joelpatterson

But then, when it comes time to make music for robots, your whole theory will go out the window.

TOBOR the 8th man
YouTube - Tobor The 8th Man Opening Theme Song


Lyric:

There's a prehistoric monster who came from outer space,
Created my the Martians to destroy the human race.
The F.B.I. is helpless, it's 20 stories tall,
What can we do?
Who can we call?

Call TOBOR, The 8th Man
Call TOBOR, The 8th Man
Faster than a rocket, quicker than a jet,
He's the mighty robot, he's the one to get.
Call TOBOR, The 8th Man
Quick, call TOBOR, the mightiest robot of them all.

[andy_simpson]

Originally Posted by RKrizman

I love that idea.

-R

If you consider the effect of tape hiss in preparing the nervous system for the attack of a loud introductory musical passage - without the hiss it can be much more surprising or alarming.

However, I'm not sure if we can consider that 'bias'.

Andy

[TOFT]

Tape hiss reminds us of cooking!

[joelpatterson]

Originally Posted by Sigma

TOBOR the 8th man....

VERY inspiring... where is that guy when we need him?

[wheever]

Originally Posted by joelpatterson

VERY inspiring... where is that guy when we need him?

By appearances he's in 1950s Japan.

[Paul Frindle]

Originally Posted by Kiwiburger

Digital white noise, as I understand it, is pure random numbers - and as such, it creates what I believe Paul Frindle would call "illegal" samples.

My understanding of what this means is that any audio waveform is - by virtue of acoustics and air pressure - a smooth, continuously varying waveform. At no point does a real analog waveform drop out or jump to an extreme value - it has to conform to the laws of physics.

A random computer generated white noise can create data that is "illegal" - in other words, could not possibly be re-created by the D/A converter. The D/A converter does it's best to create a smooth, continously varying waveform that best matches the data it is being given. The two are not the same, which is the basis for a lot of misunderstanding about digital audio.

So my guess is that analog white noise is much better than digital white noise, because it is inherently "legal". Digital white noise, i'm guessing, would probably add to the complications of illegal data - especially inter-sample peaks.

No this isn't so and I am sorry if I have given this impression at some time :-(

There is nothing illegal about digital noise provided it has been generated correctly and kept at appropriate levels (that will decode correctly in a DAC). There is also nothing that prevents digital noise being made to sound like analogue noise :-)

And people are right that low levels of noise in the background can indeed seem to help to listen and appreciate certain programme types - I have noticed this over the years.

It seems as though (providing the noise is not too noticeable) it somehow focusses attention on the sound source, rather than distracting - especially that from play out systems..

I have various home grown theories as to why this might be so, but my main theory is that it somehow keeps the ear/brain system 'alive' so that attention is not lost in the quiet periods.

What we hear from speakers and gain from the sound is closely coupled to room acoustics - so our brains process the room as well as the music from the speaker. Is it possible that quiet passages allow our brain to take it's 'eyes off the ball' and force it to recalibrate at the beginning of each louder section? If so, is it possible that some barely noticeable background noise going through the system keeps the sound of the speakers in the room live in our brains, so that the recalibration is not necessary and therefore we apparently hear more detail from the sound?

One bit of evidence I have that something like this could be going on is that ambient noise that does not come through the reproduction system itself (like air con noise etc..) does indeed distract rather than enhance - suggesting that it is our perception of the reproduction system that is at the root of the phenomenon.. Another bit of evidence is that the noise seems to enhance stereo imaging - which again suggests that it helps our ear/brains systems cope with what are only partial spacial cues from the stereo speaker set up?

Another one of those fascinating audio puzzles..

[Kiwiburger]

Thanks for correcting me there Paul - I appreciate your excellent teaching on this subject.

You say digital white noise is ok, as long as it's "generated correctly". I have a foggy recollection from somewhere of somebody explaining that white noise generated simply by random numbers would not be correct, sorry to imply this was from you.

I like your theory about noise keeping our brains alive - sounds very feasible to me.

I was playing with a visual application the other day that is a circle of large pink dots. The software turns off one pink dot at a time in a sequence. The strange thing is that our eyes/brain don't perceive this that way. Why we see is a green dot, going around the circle. And if we keep staring at it, the pink dot's disappear! This is a cool invisibility experiment, and probably something in our wiring that is exploited by stage magicians.

The way our brain and memory works fascinates me. The way it recognises complex patterns, and choses to ignore some things, is way beyond the binary logic stuff that I mess around with.

I't wouldn't surprise me that our ears play similar tricks on us. I read a theory somewhere that the physical size of our inner ears shouldn't be big enough to respond to low frequencies. The theory is that noise is necessary to be able to hear in the first place. Probably contraversial stuff - they suggested experments where perceived low end could be restored by adding noise.

I would love to see DAWs that have options for different flavours of analog noisefloors - and for wow & flutter and other distortions.

[robot gigante]

One of my favorite tricks is to take hiss, run it through a leslie or leslie simulator, and stick it low enough in a mix so that is is barely audible. It sounds nice loud too.

[RKrizman]

I like to use a recording of air and distant running water I made at King's Canyon.

-R

[peeder]

Well one thing you mustn't forget is the masking property of noise...it will cover up nasty inharmonics and higher-order harmonics and things that might otherwise sound bad.

Another thing about the width to consider is the fact that uncorrelated noise will modulate a signal ever so slightly left and right.

I like the theory about retaining attention though.

Although I'm not sure this wouldn't be a kind of thing that reverses after a few minutes...for instance, red walls initially are provocative but become relaxing after ten minutes or so, as the effect "wears off", and blue ones behave the opposite way...and that's why hospitals adopted green because it's neutral psychologically. I would guess that hiss becomes soporific after a while, which may or may not be consistent with your musical goals...

[biggator6]

I like to use a recording of air and distant running water I made at King's Canyon.

Now, the sound of running water is definitely a brain-bias.. do people often go 'wow, that sounds great - but I need to pee!'
"-)

[rackdude]

Originally Posted by Paul Frindle

No this isn't so and I am sorry if I have given this impression at some time :-(

There is nothing illegal about digital noise provided it has been generated correctly and kept at appropriate levels (that will decode correctly in a DAC). There is also nothing that prevents digital noise being made to sound like analogue noise :-)

And people are right that low levels of noise in the background can indeed seem to help to listen and appreciate certain programme types - I have noticed this over the years.

It seems as though (providing the noise is not too noticeable) it somehow focusses attention on the sound source, rather than distracting - especially that from play out systems..

I have various home grown theories as to why this might be so, but my main theory is that it somehow keeps the ear/brain system 'alive' so that attention is not lost in the quiet periods.

What we hear from speakers and gain from the sound is closely coupled to room acoustics - so our brains process the room as well as the music from the speaker. Is it possible that quiet passages allow our brain to take it's 'eyes off the ball' and force it to recalibrate at the beginning of each louder section? If so, is it possible that some barely noticeable background noise going through the system keeps the sound of the speakers in the room live in our brains, so that the recalibration is not necessary and therefore we apparently hear more detail from the sound?

One bit of evidence I have that something like this could be going on is that ambient noise that does not come through the reproduction system itself (like air con noise etc..) does indeed distract rather than enhance - suggesting that it is our perception of the reproduction system that is at the root of the phenomenon.. Another bit of evidence is that the noise seems to enhance stereo imaging - which again suggests that it helps our ear/brains systems cope with what are only partial spacial cues from the stereo speaker set up?

Another one of those fascinating audio puzzles..

God, this will be great for a sociology experiment

[Grizzly]

Originally Posted by biggator6

Now, the sound of running water is definitely a brain-bias.. do people often go 'wow, that sounds great - but I need to pee!'
"-)

Oh, so that's what they use in Céline Dion's albums !...

[Kiwiburger]

'mkaaay ... here is the original quote from Paul Frindle (lifted from PSW) that I obviously misunderstood - but I think it's relevant to the discussion:

Actually (at the risk of putting the cat amongst the pigeons) I can suggest a simple experiment people can do themselves to illustrate this in action in the most graphic way, which should dispel any lingering doubt that it's important.

The aim is to show that what looks like a legal 'signal' way below any red light in your system can still represent something that cannot pass even remotely correctly out of your digital mixer at full level. And also to illustrate how this may affect your sound quality in practice when mixing ITB. It's a kind of worst case scenario - but it illustrates the problem.

You need a W/S like ProTools, a signal generator plug-in that has a good filter section that actually goes flat to 20KHz and rolls off at 24dB/oct or so.

- In Pro tools get a mono channel up,

- stick the PT generator plug-in at the beginning of the channel and set it for sine at say 1-2KHz.

- Follow this with a good filter plug-in set for the max slope at 20KHz. (For example the Oxford EQ plug-in has 36dB/oct at 20KHz and illustrates this well - any other good HF filter should work as well).

- As an initial test set the channel fader at 0dB and note that the PT meters shows the sinewave signal at -6dBr and that putting the filter plug-in in and out using bypass has no effect.

- OK now switch the signal genny to white noise and note that the level on PT is still -6dBr.

- Now un-bypass the filter plug-in and watch the signal level rise dramatically!! In the case of the Oxford 36dB/oct filter the meter level will rise a full 5dBr to nearly flat out.

Ok so what's happening - how is this possible? Well the digital genny plug-in produces sinewaves correctly - but when in noise setting it is just a random number generator driving the output. So although when set to -6dB peak value no sample ever gets to be greater than 50% modulation - a reconstruction of the undecoded SAMPLE VALUES produces nearly full level SIGNAL. Reconstruction means filtering and so the filter plug-in is acting like a partial reconstruction filter (much like a DAC) - which in turn is now feeding a more legitimate SIGNAL which the sample value only meter can read more correctly.

It was specifically this part that I was trying to convey: "Well the digital genny plug-in produces sinewaves correctly - but when in noise setting it is just a random number generator driving the output. So although when set to -6dB peak value no sample ever gets to be greater than 50% modulation - a reconstruction of the undecoded SAMPLE VALUES produces nearly full level SIGNAL. Reconstruction means filtering and so the filter plug-in is acting like a partial reconstruction filter (much like a DAC) - which in turn is now feeding a more legitimate SIGNAL which the sample value only meter can read more correctly.
"

Sorry I cocked this up - i'm still not 100% sure what part I misunderstood.