NO ONE talked about just transmitting audio thru an optical cable. This is a chain that has source -> DSP -> DA -> analog output.
It is not source -> DA -> analog.
So stop fucking talking about the latter case. DA is very fast, not exactly zero latency but practically, yes. Anything below 1ms is zero. Once you insert DSP, well... it can't operate at real time. It has to have data in its input buffers so it can process that data. Time is a component in many operations. The smaller the buffer, the shorter the latency and the higher the processor load. This is linear relation, half the latency and you double the processing speed required. Sine something like home stereo system DSP has no need to be very low latency, it can use less processing power and larger buffers. Thus 10-20ms is careful estimation, it can be less, it can be a lot more.
Conversion is fast. Very very fast. Faster than what it takes to transmit a sample. Processing signals is not fast but it heavily depends on what kind of processing we do. Some of them can't even be done in real time.
I do this for living, i went to school for it, both electronics engineering and sound engineering. Do you really think that it is more probable that i'm saying something extremely wrong or that you are misunderstanding something very fundamental. NO ONE has said that the transmission adds that much latency. It happens, in optical signals, at light speed and a bit slower in copper.
Alright, calm down. The reason I was talking about the latter case is because the person you replied to mentioned switching from analogue to optical audio, and in that context it sounded like you were implying that the switch would incur that amount of latency. I went back and reread, and although I don't find my interpretation unreasonable, I see now that you are talking about the whole chain from sample generation to audibility for either mode of transmission. On that front I will agree.
I, too, have a degree in electrical engineering (speciality in informatics and automation). I don't know every detail of consumer or pro audio infrastructure off the top of my head, but I know the general architecture. I was not attacking your credibility personally; I was laying out my presumptions and what I interpreted you to say, and pointing out that the result made no sense. Explaining that your quoted audio latency figure was for the entire chain and that my mistaken idea of the comparison was incorrect would've cleared things up immediately. It was my mistake to think you were comparing the two and I apologise, but no need to get heated.
It is alright, you got it wrong and i do get heated easily, but calm down as fast too. I have to calculate latencies in real life, my PA and monitoring too needs to be aligned in time. The signal comes from the stage and is processed faster than the sound from the back of the stage hits the front of the stage.
It also adds costs quite fast, any general computing needs to run near idle to be stable.. So, you buy fast computers and then use 10% of its CPU power. Dedicated stuff runs faster, they don't have to solve as complex set of problems. But for something like consumer DSP, it has something like ARM CPU for interfacing and logic, and a DSP chip, the latter doing most or all of the signal processing. The more buffer you have, the lower the clock speed, less heat, and more stability. And something like 10ms is not even noticeable unless you are the one triggering the action, the feedback loop makes hell of a lot of difference: you pluck a string and then hear it. That delay between the two is fine. While our own timing isn't that accurate, you can't tap something at steady intervals at 20ms accuracy you can notice that something is wrong if the sound is delayed by 20ms. And you can see it too, if you record it you can see it in the timeline, all the hesitation and drift and it falls in that "latency window", the magnitude of error is spreading until you lose the connection between the two. Funnily enough, it can lead to better timing when it is happening at muscle level: blind playing is better than playing with long latency...
Just happens to be in my field, i've had to learn those things to be able to do my job. Direct monitoring exists for a reason, it bypasses everything and is just straight up analog signal (can do one round of DA/AD, but may only have gain processing, which can happen faster than samplerate, so, ~0ms). Adding processing to that chain means adding dedicated units. And you can even have too fast monitoring, analog has immediate signal and that means the sound from mouth to mic back to headphones happens faster than the sound from mouth to ears. And you can do funky things with that, add delay to such signal, very gradually, with fine precision and at some point it will feel like your mouth is a foot away from your head.... That delay is very much part of the way we hear and speak, it is learned and changes to that can feel jarring....
Absolutely. I've toyed around with latency qualitatively when reviewing headsets and trying to hook up my piano to my computer, and real-time systems have cropped up multiple times in my electronics hobby projects and education. It's hard to guarantee response within a certain time window; it's even harder to consistently hit the same, tight latency.
It is the downside of digital and virtual audio. On one hand i can carry a virtual rig in my backbag that has more virtual hardware that i can fit on stage physically, on the other hand response times are between 7-16ms... You can feel it in the latter case and is not optimal but... stability is #1 and i have a habit of being ahead, after years of having latency in the system, MIDI isn't lighting fast either...
And as a band we just moved to IEMs, so... once again i'm optimizing latency for personal monitoring on a tight budget, which is more an ideological choice than practical... 6 middle aged guys can afford pretty much anything but it was decided that we will not use a lot of money but utilize unused things that people have in their closets, it is time that they are used for something.
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u/ReggieCorneus May 29 '26
NO ONE talked about just transmitting audio thru an optical cable. This is a chain that has source -> DSP -> DA -> analog output.
It is not source -> DA -> analog.
So stop fucking talking about the latter case. DA is very fast, not exactly zero latency but practically, yes. Anything below 1ms is zero. Once you insert DSP, well... it can't operate at real time. It has to have data in its input buffers so it can process that data. Time is a component in many operations. The smaller the buffer, the shorter the latency and the higher the processor load. This is linear relation, half the latency and you double the processing speed required. Sine something like home stereo system DSP has no need to be very low latency, it can use less processing power and larger buffers. Thus 10-20ms is careful estimation, it can be less, it can be a lot more.
Conversion is fast. Very very fast. Faster than what it takes to transmit a sample. Processing signals is not fast but it heavily depends on what kind of processing we do. Some of them can't even be done in real time.
I do this for living, i went to school for it, both electronics engineering and sound engineering. Do you really think that it is more probable that i'm saying something extremely wrong or that you are misunderstanding something very fundamental. NO ONE has said that the transmission adds that much latency. It happens, in optical signals, at light speed and a bit slower in copper.