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Any one notices the cracking/popping sound of new 16 inch MBP?
- Thread starter MengkeMary
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You probably missed this thread: https://forums.macrumors.com/threads/macbook-pro-2018-speakers-crackling.2128234/
Edit: Apperantly you didn't miss it because you also posted it in
But 60 pages of replies on this issue for the 2018 model says enough I believe.Quite some users (including me) got information from "senior advisors" that it would be fixed "soon" but they never did.
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Sorry to all that have it. Sounds like it is a known software issue, so that’s much preferable to a hardware problem
Riiiiiiight.
You mean you just haven't noticed it yet...
I mean, how do I reproduce it? Fast forward a YouTube video and I am supposed to hear crackling?Riiiiiiight.
I did that. No crackling.
Another report of Apple saying it’s a software issue and a fix is in the works. I realize this has happened before and Apple never fixed it, but it’s a start:
Hey guys. I’m a software engineer with digital signal processing experience. I can tell you with 100% confidence that this is a software issue, very likely drivers. This pop happens because when audio is skipped or paused, the sample buffer is not being written or read correctly. You end up with a very small “gap” in the wave data, which then creates a momentary partial square wave. The sound you’re hearing is the square wave; it’s a sudden, sharp change in amplitude, which then pops the speaker.
This can be any one or combination of all sorts of stuff, like a synchronization issue (blocking IO during a read/write mutex), or even a thread scheduling issue (buffer written to before its processed because the DSP didn’t get enough CPU time). It could also be a bad write, like incorrectly initialized bytes (zeroes when it should be actual data, or random bytes when it should be zeroed). There are many possibilities, but they’re all well-solved.
All of this runs on Core Audio, which is Apple’s super high quality, low latency audio subsystem. These types of issues are common with low latency audio and can easily be fixed with various methods. Low latency audio takes a lot of tweaking to get right and this is just part of the process. Apple is almost always top of their class with this, so I’m pretty confident they will issue a software update with a well-tested, well-researched solution. I’m not worried.
The reason why the issue goes away if you constantly have audio playing in the background is because the system mixes all audio through Core Audio, then the mix is sent to the audio drivers at a very low level, almost directly to the wave buffer. When audio is started and stopped, or even possibly skipped around, processing is scheduled and terminated over and over, triggering the issue (whatever it is). If there is always audio playing, there is always a thread processing the buffer and always a thread writing to the buffer. This is precisely why I believe the issue is with drivers, not Core Audio; it does appear that Core Audio is doing exactly what it’s supposed to do, which would also explain why the issue is not reported on other MacBook/Pro models at this time, despite being on the same version of the operating system.
In the mean time, if you have critical audio requirements, professional audio software can take direct control of your audio interfaces, which would then circumvent these pops/clicks. So if you have a pro application, you’re fine. Audio applications will let you control sample rates and buffer size; you could temporarily run a larger buffer to avoid this issue, at the cost of higher latency. Still, it’d be low enough. It also may be a non issue if it’s constantly running the audio engine (see previous paragraph/explanation).
I hope this calms some nerves.
This can be any one or combination of all sorts of stuff, like a synchronization issue (blocking IO during a read/write mutex), or even a thread scheduling issue (buffer written to before its processed because the DSP didn’t get enough CPU time). It could also be a bad write, like incorrectly initialized bytes (zeroes when it should be actual data, or random bytes when it should be zeroed). There are many possibilities, but they’re all well-solved.
All of this runs on Core Audio, which is Apple’s super high quality, low latency audio subsystem. These types of issues are common with low latency audio and can easily be fixed with various methods. Low latency audio takes a lot of tweaking to get right and this is just part of the process. Apple is almost always top of their class with this, so I’m pretty confident they will issue a software update with a well-tested, well-researched solution. I’m not worried.
The reason why the issue goes away if you constantly have audio playing in the background is because the system mixes all audio through Core Audio, then the mix is sent to the audio drivers at a very low level, almost directly to the wave buffer. When audio is started and stopped, or even possibly skipped around, processing is scheduled and terminated over and over, triggering the issue (whatever it is). If there is always audio playing, there is always a thread processing the buffer and always a thread writing to the buffer. This is precisely why I believe the issue is with drivers, not Core Audio; it does appear that Core Audio is doing exactly what it’s supposed to do, which would also explain why the issue is not reported on other MacBook/Pro models at this time, despite being on the same version of the operating system.
In the mean time, if you have critical audio requirements, professional audio software can take direct control of your audio interfaces, which would then circumvent these pops/clicks. So if you have a pro application, you’re fine. Audio applications will let you control sample rates and buffer size; you could temporarily run a larger buffer to avoid this issue, at the cost of higher latency. Still, it’d be low enough. It also may be a non issue if it’s constantly running the audio engine (see previous paragraph/explanation).
I hope this calms some nerves.
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Hey guys. I’m a software engineer with digital signal processing experience. I can tell you with 100% confidence that this is a software issue, very likely drivers. This pop happens because when audio is skipped or paused, the sample buffer is not being written or read correctly. You end up with a very small “gap” in the wave data, which then creates a momentary partial square wave. The sound you’re hearing is the square wave; it’s a sudden, sharp change in amplitude, which then pops the speaker.
I hope this calms some nerves.
Thanks man! This is a good explanation and i wish i got something like this 3 months ago when i first contacted Apple about this. They wanted to change my speakers, go figure... As i wrote before this is the exact same square waveform that can be heard when the buffer size inside an audio app is insufficient.
Too bad that FCPX doesn't have an option to set a different buffer size and i guess this is the reason why popping doesn't occur inside Logic Pro X, right? I guess Logic uses a bigger buffer size by default so that it can handle large audio samples.
I guess we all return ours and wait for this LOL
https://www.macrumors.com/2019/12/02/16-inch-macbook-pro-mini-led-2020/
https://www.macrumors.com/2019/12/02/16-inch-macbook-pro-mini-led-2020/
I don't know anything about FCPX, but I'm assuming that since it's a video editing app, it just uses the high level system audio API, which will not allow the software to take exclusive control of the audio interface, much less even be aware of it. Just like your web browser, it probably doesn't care.
Logic Pro X, Cubase, ProTools, and other audio-specific software actually skips CoreAudio and goes straight to the driver at a very low level. They act as their own audio engines, essentially. They can have direct control of the ring buffer (among other things) that is processed by the driver, including the allocation of the buffer, which is how these apps let you select how many "samples" large the buffer is. They are also directly responsible for writing data to that buffer, rather than asking the operating system's audio engine (Core Audio) to do it on its behalf. With that fine, low level control, these apps are basically "always on" and your system is constantly running the audio pipeline, rather than turning on an off when sounds are being played, stopped, etc.
Without actually having access to Apple's code (and I'm really not an expert), my guess is that Core Audio has some power consumption optimizations that will start and stop the ring buffer processing, but there's some type of timing or IO issue at the driver level when the pipeline starts and stops. Wild guess here; I have no evidence to back this up.
So now to answer you directly about Logic...
My guess, without looking at code and instrumenting/debugging the system, is that Logic Pro doesn't pop not because of the buffer size, but because it is "always on." In fact, most software like that end up using hacks and micro-optimizations to use an even *smaller* ring buffer to lower the latency even more!
"Samples" is a loaded term that means two things:
1. To a musician, it's a sound clip, like an instrument or something. A whole sound.
2. To a digital signal engineer, it's a momentary, digital approximation of an analog signal.
So when marketing material says something can handle large samples, they're talking about definition number one. What you want your software to do is to actually have the smallest sample buffer your hardware/software can physically handle without race hazards (which causes pops).
This was fun. I basically never get to talk about this stuff in normal, plain English. Woohoo!
Okay, I listened to the samples people posted.
That is not a “crackling;” that is a faint popping sound after hitting the fast forward.
I can confirm I have it as well, although I didn’t notice it until I read about it on here.
It’s faint to me and doesn’t sound like a “crackling” at all.
Whatever—thanks, because now I can’t unhear it.
Sorry that you can't not hear it now, but the more people hammering Apple the better the chance they will actually do something.
If true it should be a piece of cake fix for Apple. One that should have already been implemented.
Whats odd is I was messing around with a 13 inch (2019 2 Thunderbolt model) that kind of does the same thing when skipping through you tube occasionally (not as noticeable likely because the speakers on this "base" model are so paltry by comparison to the 16 that it can't project the lower frequency that I believe the "pop" resides in.
So it does make me think that its more a software issue like mentioned above
So it does make me think that its more a software issue like mentioned above
I have been able to reproduce this both with internal speakers when skipping/seeking in YouTube (Safari), and with headphones plugged into the headphone jack when adjusting volume levels.
Part of me thinks this is a software bug, but what we really need now is for a few brave souls to try and reproduce this on Windows or Linux (via Boot Camp)
Part of me thinks this is a software bug, but what we really need now is for a few brave souls to try and reproduce this on Windows or Linux (via Boot Camp)
I know it is not the Apple way, but considering that this issue affects many if not most/all of the 16" models, I think it would be in their best interest to acknowledge it and report publicly that they are working on a fix. Otherwise they may have lines at the Apple stores similar to new product launches on Jan 8, with people returning their computers because of an issue the employees "have never heard of before".
I hate to say this, but I returned mine the next day after buying it. I have ZERO tolerance for this kind of sloppy B.S. out of Apple. I miss Steve...
Something I do not understand about MR is why they seemingly ignore issues like this? You'd think that they would be all up in Apple's grill to help their audience. Instead they sit idly by with their lips buttoned. It's a shame that MR will bitch at Apple about certain miniscule things, but then totally gloss over REAL issues like this.
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