[RWP] Latency, is shorter always better?

Chris Belle cb1963 at sbcglobal.net
Mon Aug 4 15:22:00 EDT 2014 

Absolutely.

On 7/23/2014 1:20 AM, John Chilelli wrote:
> Amen and right on brother.  A correcting higher perspective to have indeed!
>
> -----Original Message-----
> From: RWP [mailto:rwp-bounces at reaaccess.com] On Behalf Of Keith Hinton
> Sent: Tuesday, July 22, 2014 11:42 PM
> To: Reapers Without Peepers
> Subject: Re: [RWP] Latency, is shorter always better?
>
> Things might suck, but with the wonderful laber of love that Jim still
> does in the form of HotSpotClicker, he's made the world a brighter
> place for those of us who want to create music, amongst other uses of
> HSC. That's got to be a bright spot, in the darkness of suckyness. We
> can't dwell too much on what sucks for us, but do what we can. We
> won't ever have absolute perfection in this world, so forget a 100
> percent accessible never broken buggy system; that won't happen,
> unless Jesus himself makes it. Only the day of the Resurrection for
> those of us who believe will be that day of perfection. For blindness
> will be a thing of the past then. Never forget what scripture clearly
> says either. That all things of this Earth are temporary.
> What we can see will last only for a short time.
> But what we cannot see, will last forever.
> Think on that.
> Blessings.
>
> On 7/22/14, Jim Snowbarger <Snowman at snowmanradio.com> wrote:
>> well said.
>>
>> ----- Original Message -----
>> From: "Chris Belle" <cb1963 at sbcglobal.net>
>> To: "Reapers Without Peepers" <rwp at reaaccess.com>
>> Sent: Tuesday, July 22, 2014 9:02 PM
>> Subject: Re: [RWP] Latency, is shorter always better?
>>
>>
>>> Plus, there are very few coders left who know how to think in machine
>>> language, they just glue modules together now.
>>>
>>> NO wonder everything sucks so bad.
>>>
>>>
>>> On 7/22/2014 12:10 PM, Jim Snowbarger wrote:
>>>> Would a 30 billion gigahertz processor talk fast?
>>>> I think we have almost reached the physical limit on processor speed.
> It
>>>> has to do with the speed of light, and the distances of the connecting
>>>> lines that connect up your various components, plus the inevitable
>>>> capacitence that such lines represent, and how that interacts with
>>>> frequency.   And yes, Keith is right, more power is required to drive
>>>> such attempts.
>>>> Basically, we're going to have to go lazar now in order to get any
>>>> significant increase in speed.
>>>> Either that, or stop writing such crappy, bloated software. Hmmm.
>>>> Imagine that possibility.
>>>> Nope, that won't happen.  Time to market would suffer, and we would all
>>>> fall asleep from bordom.
>>>> Can't have that!
>>>>
>>>>
>>>> ----- Original Message ----- From: "Keith Hinton"
>>>> <keithint1234 at gmail.com>
>>>> To: "Reapers Without Peepers" <rwp at reaaccess.com>
>>>> Sent: Tuesday, July 22, 2014 10:48 AM
>>>> Subject: Re: [RWP] Latency, is shorter always better?
>>>>
>>>>
>>>>> We expect a little baby toy  computer to become a huge, furry kitty
>>>>> cat with paws waving around and a tail that swishes and a meow to
>>>>> escape the voicebox of the CPU. LOL just kidding.
>>>>> Couldn't resist.
>>>>> Fun thread for sure, I'm liking reading all about this stuff.
>>>>> I didn't know digital audio was so latency-crazy.
>>>>> But apparently it is.
>>>>> As for 30 Gigahurts?
>>>>> Why not 1 billion gigahurt processors? LOL!
>>>>> Could you imagine how high your electrical bill would be?
>>>>> one billion gigahurts with a quadrillion cores.
>>>>> Bet you couldn't even run something like that. LOL.
>>>>> Not realistically.
>>>>>
>>>>>
>>>>> On 7/22/14, Jim Snowbarger <Snowman at snowmanradio.com> wrote:
>>>>>> Tape decks with a moveable playback head?  Very nice.  I didn't know
>>>>>> about
>>>>>> that.  But, that would have been great for adjusting the rate of
>>>>>> regenerative feedback to match the tempo of a song.
>>>>>> Another way to do that was to vary the speed, except that it had
>>>>>> frequency
>>>>>> response implications as well.
>>>>>>
>>>>>> An interesting experiment with DAWs, record a series of clicks into
>>>>>> track 1.
>>>>>>
>>>>>> Arm track 2, and route the playback of track 1 into the input for
> track
>>>>>> 2.
>>>>>> Do it externally, rather than inside the computer, so you get the
>>>>>> benefit of
>>>>>>
>>>>>> the entire chain of processing.
>>>>>>
>>>>>> Now, play tracks 1 and 2 back together.  Listen for the time delay
>>>>>> between
>>>>>> the clicks on the two tracks.  Ideally, they will be coincident.
>>>>>> On reaper here, it isn't quite perfect, but it is pretty darned good.
>>>>>> Last time I tried Audacity, they arrived in different time zones.
>>>>>>
>>>>>> ----- Original Message -----
>>>>>> From: "Chris Belle" <cb1963 at sbcglobal.net>
>>>>>> To: "Reapers Without Peepers" <rwp at reaaccess.com>
>>>>>> Sent: Tuesday, July 22, 2014 12:46 AM
>>>>>> Subject: Re: [RWP] Latency, is shorter always better?
>>>>>>
>>>>>>
>>>>>>> One more thought  about this latency thing.
>>>>>>>
>>>>>>> And us old farts who used to play with tape decks will remember this.
>>>>>>>
>>>>>>> How about those 3 head decks where you could listen to play-back
>>>>>>> while
>>>>>>> recording?
>>>>>>>
>>>>>>> YOU could hear the input while it was going down, and listen to your
>>>>>>> playback head, and some of those were moveable.
>>>>>>>
>>>>>>> So you could change the latency between when something got recorded
>>>>>>> and
>>>>>>> played back by moving the head closer or further away from the
>>>>>>> recording
>>>>>>> head.
>>>>>>>
>>>>>>> That was on the commercial machines.
>>>>>>>
>>>>>>> I never had one of those, but i did have a very nice 3 head cassette
>>>>>>> deck.
>>>>>>>
>>>>>>> This is, in fact, somewhat similar to what hapens in your daw,
>>>>>>> even if your not recording but just listening to the signal comming
>>>>>>> back
>>>>>>> from your daw once it goes through the internal processing, and any
>>>>>>> plug-ins you might have,
>>>>>>> and they add their own latency you can bet, and most modern daws
>>>>>>> compensate for that under the hood.
>>>>>>>
>>>>>>> Sonar had automatic plug in delay compensation
>>>>>>> way before many daws, including protools ever had it.
>>>>>>>
>>>>>>> Yes, you go back and listen to first episodes of the home recording
>>>>>>> show
>>>>>>> on protools 9 and 10,
>>>>>>> and you can hear them talking about lining up tracks manually after
>>>>>>> the
>>>>>>> fact, to make the audio come out right, after going through all the
>>>>>>> processing plugs.
>>>>>>>
>>>>>>> Boy howdy, now, isn't that a real pain in the posterior?
>>>>>>>
>>>>>>> INteligently keeping up with when in the time line a recording
> starts,
>>>>>>> and
>>>>>>>
>>>>>>> how to play it precisely in the right way to account for plug-ins
>>>>>>> latencies, and then play it properly again when you take plugs of is
>>>>>>> not
>>>>>>> an easy task, but your daw does that all for you under the hood, if
>>>>>>> it's
>>>>>>> worth a squat.
>>>>>>>
>>>>>>> People sometimes get in real trouble even with this automatic
>>>>>>> stuff going on by not routing their monitoring right,
>>>>>>> because there are certain ways of routing and recording which makes
>>>>>>> it
>>>>>>> impossible for your daw to implement delay compensation properly.
>>>>>>>
>>>>>>> So this is why I tend to like to not do plugs until after I've laid
>>>>>>> my
>>>>>>> audio.
>>>>>>>
>>>>>>> Not always possible, you can't lay that heavy rock guitar track
>>>>>>> easily
>>>>>>> only hearing plink, plunk, twang,
>>>>>>> but you can believe your daw is doing the latency shuffle dance when
>>>>>>> you
>>>>>>> have many tracks playing and you are laying guitar amp simms which
>>>>>>> has
>>>>>>> latency going both ways, because remember, you are going audio in,
>>>>>>> and
>>>>>>> audio back out,
>>>>>>> and this is why with mastering plugs which cause a lot of latency,
>>>>>>> especially multi-band compressors with look ahead and back in my
>>>>>>> early
>>>>>>> early days of learning this stuff it used to drive me nuts, why are
>>>>>>> my
>>>>>>> midi tracks being delayed so much when I press a note but they play
>>>>>>> just
>>>>>>> fine on playback?
>>>>>>>
>>>>>>> Well, it's that delay compensation working for you.
>>>>>>>
>>>>>>> Imagine having to figure out how much delay you had and fixing all
>>>>>>> that
>>>>>>> manually?
>>>>>>>
>>>>>>> You can get interesting things happening when using reverb in
> projects
>>>>>>> by
>>>>>>>
>>>>>>> turning off delay compensation,
>>>>>>> you get a built in pre-delay, which is a setting on high quality
>>>>>>> reverb
>>>>>>> units, the reverb doesn't start right away, and
>>>>>>> this helps make room in the mix when you don't wan the verb in the
>>>>>>> way,
>>>>>>> and it kicks in after the initial atack of your audio.
>>>>>>>
>>>>>>> Or do we remember real world latency,
>>>>>>> and the days when distructive editing was the only kind you did, if
>>>>>>> you
>>>>>>> wanted to process an equalizer, or chorus fx, you hit the button, and
>>>>>>>
>>>>>>> then
>>>>>>>
>>>>>>> go have a sandwich and waited for your 486 to process that track, and
>>>>>>> you'd come back 10 minutes later and maybe have a wet and dry track.
>>>>>>> and you could do interesting things with that by time delaying the
>>>>>>> wet
>>>>>>> track 'grin'.
>>>>>>>
>>>>>>> When I do drum replacement by generating midi tracks from transient
>>>>>>> points
>>>>>>>
>>>>>>> of an audio drum track and then feeding it to a audio bus with
>>>>>>> samples, I
>>>>>>>
>>>>>>> have to time align the new track to match the old one,
>>>>>>> at least in the old days we had to do more of that before delay
>>>>>>> compensation was automatic.
>>>>>>> in most daws.
>>>>>>>
>>>>>>> Still, most daws will only do this in a certain range, see above,
>>>>>>> where I
>>>>>>>
>>>>>>> mention mastering plugs,
>>>>>>> linear phase equalizers are also notorious for introducing way too
>>>>>>> much
>>>>>>> delay to use them in real time.
>>>>>>>
>>>>>>> So are transient  processors, shapers.
>>>>>>>
>>>>>>> Maybe when we get processors running at 30 gigahertz
>>>>>>> we'll be able to do that stuff in real time, and did I hear silly
>>>>>>> people
>>>>>>> want to make a daw out of an ipad?
>>>>>>>
>>>>>>> Right now in 2014, an ipad will just barely run a guitar simm with
>>>>>>> low
>>>>>>> enough latency
>>>>>>> \to be playable.
>>>>>>>
>>>>>>> Well, what do you expect from a little baby toy computer?
>>>>>>>
>>>>>>>
>>>>>>> On 7/21/2014 9:33 PM, Jim Snowbarger wrote:
>>>>>>>> Now and then, I feel like a slight departure from topic..  And, this
>>>>>>>>
>>>>>>>> is
>>>>>>>> one of them.  So, stand bye with your delete key ready as I carry
>>>>>>>> on.
>>>>>>>>
>>>>>>>> This probably belongs over on MidiMag.  But, I don't feel like
>>>>>>>> joining
>>>>>>>> just so I can post this once in a blue mooner.
>>>>>>>>
>>>>>>>> One of the great things that digital audio processing has brought to
>>>>>>>>
>>>>>>>> us
>>>>>>>> is so-called latency.  You might just call it delay.  but, in the
>>>>>>>> 21st
>>>>>>>> century, we like to use clever names.  It makes us feel smarter.
>>>>>>>> So,
>>>>>>>> let's co-opt the term latency, which had a totally different meaning
>>>>>>>> before the techno-gods got hold of it. And, let's now define latency
>>>>>>>>
>>>>>>>> as
>>>>>>>> the act of being late.  But, however you slice it, it comes down to
>>>>>>>> delay.
>>>>>>>>
>>>>>>>> Digital devices impose delay mostly because data consumers, like
>>>>>>>> sound
>>>>>>>> cards, or recording devices, have learned to be defensive, knowing
>>>>>>>> full
>>>>>>>> good and well that data providers, such as input sound cards, or
>>>>>>>> other
>>>>>>>> streaming devices, can not be counted on to keep up a steady stream
>>>>>>>> of
>>>>>>>> data.  Internet congestion, or scheduling congestion inside your own
>>>>>>>> machine, can temporarily block the normal flow of things. Sound
>>>>>>>> playback
>>>>>>>>
>>>>>>>> requires a rock-solid comsumption rate of the data. The sampels need
>>>>>>>>
>>>>>>>> to
>>>>>>>> keep flowing. You might not get that next buffer load of data in
>>>>>>>> time.
>>>>>>>> so, it pays to keep a backlog.  The more backlog, the safer you are.
>>>>>>>> But, if the backlog is too great, you get, latency, that annoying
>>>>>>>> delay.
>>>>>>>>
>>>>>>>> I recently picked up one of those fine Computers Chris is always
>>>>>>>> talking
>>>>>>>>
>>>>>>>> about from StudioCat.com.  That is one very fine box. And, now that
>>>>>>>> I
>>>>>>>> also own Chris's Delta 1010, I was enjoying fine-tuning my latency
>>>>>>>> down
>>>>>>>> to acceptable levels,  not carefully measured, but clearly less than
>>>>>>>>
>>>>>>>> 10
>>>>>>>> milliseconds.
>>>>>>>>
>>>>>>>> Most of the recording work I do involves a microphone and
> headphones.
>>>>>>>> I
>>>>>>>>
>>>>>>>> am quite typically listening to my own voice as I speak. If you have
>>>>>>>> listened to the Snowman Radio Broadcasts, you know the kind of
>>>>>>>> multi-track microphone work I'm guilty of.
>>>>>>>> When living on machines where such short delays were not possible,
>>>>>>>> my
>>>>>>>> habit was to listen to my own foice direct out of the mixer, and not
>>>>>>>> going through Reaper.  So, I kept the reaper monitor off. What was
>>>>>>>> annoying about that is that, if I panned my various character voices
>>>>>>>>
>>>>>>>> in
>>>>>>>> the stereo  mix, then, my direct microphone sound would not be
> panned
>>>>>>>> the
>>>>>>>>
>>>>>>>> same as the character voice track I was recording into. So, when it
>>>>>>>> played back, it came from elsewhere, and was more than a little bit
>>>>>>>> confusing.
>>>>>>>>
>>>>>>>> But, with delay this short, I find that I switch off the direct
>>>>>>>> sound,
>>>>>>>> and now can monitor the signal coming back from reaper with the
>>>>>>>> monitor
>>>>>>>> turned on.  So, I'm now listening to a delayed version of my voice,
>>>>>>>> and
>>>>>>>> it is panned to the same place where that character voice sits,
>>>>>>>> which
>>>>>>>> helps me keep track of who I am supposed to be right now. And, I can
>>>>>>>> more easily tell now whetehr a track is armed, and even if one is
>>>>>>>> armed
>>>>>>>> that should not be. It's nice to be able to work like that, just
>>>>>>>> listening to reaper's output.
>>>>>>>>
>>>>>>>> But, here is the cool thing.  The exact amount of latency you
>>>>>>>> provide
>>>>>>>> affects the quality of what you hear in your headphones.
>>>>>>>>
>>>>>>>> No matter how good your phones, the sound that you hear when you are
>>>>>>>> listening to yourself speaking live into a microphone, is actually
>>>>>>>> the
>>>>>>>> composite of at least two signal paths, and maybe more. Yes, there
>>>>>>>> is
>>>>>>>> the direct signal coming through Reaper. Then, there is bone
>>>>>>>> conductivity, the sound of your own voice coming through the
>>>>>>>> structure of
>>>>>>>>
>>>>>>>> your head, which will very somewhat with density.  If you don't get
>>>>>>>> any
>>>>>>>> of that, you might wonder about that density stuff.
>>>>>>>> And maybe even, there is leakage around the ear muffs.  In all, it
> is
>>>>>>>> a
>>>>>>>> complex sond that actually reaches your ears.  And, the phase
>>>>>>>> relationship between all of the various contributors will affect the
>>>>>>>> frequency response of the final signal that you hear.
>>>>>>>>
>>>>>>>> In the old days, we knew about the affect that phase would have on
>>>>>>>> such
>>>>>>>> things.  Having your head phones out of phase with your microphone
>>>>>>>> left
>>>>>>>> you feeling empty headed, due to the phase cancellation that took
>>>>>>>> place.
>>>>>>>> But, since delay was in the nanoseconds, we didn't get to know so
>>>>>>>> much
>>>>>>>> about the effect that delay would have, despite our compulsive
>>>>>>>> preoccupation with tape delay.
>>>>>>>>
>>>>>>>> Phase is mostly a frequency independent phenomenon.  Yes, we know
>>>>>>>> that
>>>>>>>> some systems, especially mechanical transducers, or even cheap
>>>>>>>> equalizers, which will have a reactive component to their impedance,
>>>>>>>> introduce a variable amound of phase shift, depending on frequency.
>>>>>>>> But,
>>>>>>>>
>>>>>>>> usually those effects are at the far ends of their usable range.
>>>>>>>> In general, especially in mixer land, where things are nice and
>>>>>>>> linear,
>>>>>>>> and where impedances are strictly non-reactive, if you put something
>>>>>>>>
>>>>>>>> 180
>>>>>>>>
>>>>>>>> degrees out of phase, you will get perfect cancellation, all across
>>>>>>>> the
>>>>>>>> frequency band.
>>>>>>>>
>>>>>>>> Enter the digital age, and the new innovation, latency.
>>>>>>>> The relationship between signal phase, and a delay is frequency. For
>>>>>>>> example, a delay of 4 milliseconds is one full cycle of a 250 Hertz
>>>>>>>> tone.
>>>>>>>>
>>>>>>>> But, it is only half a cycle of a 125 hertz tone.   It is all still
> a
>>>>>>>> 4
>>>>>>>> millisecond delay.  But, the phase impact depends on the frequency.
>>>>>>>> Combining the pre and post delays of these two tones with that 4ms
>>>>>>>> delay
>>>>>>>>
>>>>>>>> will have completely different effects. The 125 hertz tone would be
>>>>>>>> nulled out.  The 250 hertz tone would actually see a 6 db increase.
>>>>>>>>
>>>>>>>>
>>>>>>>> The result is that, if you put a delay in front of your headphone
>>>>>>>> mix,
>>>>>>>> you will cause what is referred to as a comb filter effect on the
>>>>>>>> perceived headphone signal.  It is a filter that has a frequency
>>>>>>>> response
>>>>>>>>
>>>>>>>> curve that looks like a rola coaster, with hills and valleys.  If
>>>>>>>> you
>>>>>>>> were listening to an audio tone sweep, one that you would actually
>>>>>>>> need
>>>>>>>> to sing, in this case, in order to get that bone conductivity thing
>>>>>>>> happening as well, As you move steadily up in frequency, the sound
>>>>>>>> would
>>>>>>>>
>>>>>>>> be much stronger at some frequencies, and much weaker at others.  As
>>>>>>>>
>>>>>>>> the
>>>>>>>>
>>>>>>>> tone rises, you would hear rising and falling of the net response.
>>>>>>>> And,
>>>>>>>>
>>>>>>>> changing the amounbt of delay slides that comb up and down the audio
>>>>>>>> spectrum.
>>>>>>>> Depending on several things, the frequency range of your voice,
>>>>>>>> response
>>>>>>>>
>>>>>>>> of your headphones, your ears, the density of your grey matter, your
>>>>>>>> preferences, and on and on, you might have preferences about the
>>>>>>>> optimal
>>>>>>>>
>>>>>>>> position of that comb.  What frequencies do you like to accentuate?
>>>>>>>> And,
>>>>>>>>
>>>>>>>> which to attenuate.
>>>>>>>>
>>>>>>>> The cool thing is that, by fine-tuning your headphone latency, you
>>>>>>>> can
>>>>>>>> position that comb how you like, and can optimize your headphone
>>>>>>>> experience. The latency needs to be short enough to not give you a
>>>>>>>> delay
>>>>>>>>
>>>>>>>> echo effect. But, beyond that, the shortest possible latency may not
>>>>>>>>
>>>>>>>> give
>>>>>>>>
>>>>>>>> you the headphone experience you like.  Instead, relax it a little,
>>>>>>>> and
>>>>>>>> see what enriching tones come your way.
>>>>>>>> Silly you.  And you always thought shorter was better. And now you
>>>>>>>> know.
>>>>>>>> TROTS.
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
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>>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
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>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> RWP mailing list
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>>>>>>
>>>>>
>>>>> --
>>>>> Sincerely,
>>>>>
>>>>> Keith
>>>>>
>>>>> Home Phone:
>>>>> 928-554-3936
>>>>> Mobile Phone:
>>>>> 928-713-6370
>>>>> Primary email:
>>>>> keithint1234 at gmail.com
>>>>> Twitter:
>>>>> @keithint1234
>>>>> Facebook:
>>>>> http://facebook.com/keith.hinton1
>>>>> Skype:
>>>>> skypedude1234
>>>>>
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>>>>>
>>>>
>>>>
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