10.4.10 Audio Popping Issues: Information Check with Internal Speakers

Question

For people with internal speakers, or those without subwoofers: Please read all the way to the bottom to find a test that will determine whether you are also having audio problems, even if you can't hear pops.
We've had a lot of discussion about audio popping due to 10.4.10, and the evidence indicates that the audio circuitry is going to sleep to conserve power, even on AC-only computers like the iMac, Mac Mini, and (at least one) Mac Pro. Some people claim to not have this problem, but I'm wondering if they just aren't noticing it.
Having external speakers with a subwoofer, set to high amplification, are key to obvious detection of the problem. Let the sound subsystem go idle for 30+ seconds (wait a minute with no audio, just to be safe), turn up your external speakers really loud, and cause the computer to make a sound. You should hear a burst before the sound plays. If you repeat the sound, you won't hear the burst. This is the sound of the audio circuitry powering on, and the speakers are amplifying it.
About 30 seconds after the sound finishes playing, if you leave the volume of your speakers turned way up, you should hear a "pop" as the circuitry is powered off. Then, playing another sound will recreate the burst.
I haven't been able to hear these sounds with internal speakers, either on the Mini or iMac. But the problem still exists, and it is detectable... if you know what you are looking for.
The burst of the audio circuitry turning on also causes a delay in the audio. The delay is a noticeable fraction of a second, an it can easily be detected if you have a repeatable source of sound. I like Terminal.app, because I use that application all day, every day. Here is how you can check to see if you are also subject to the audio problems:
1. Start Terminal.app (in the /Applications/Utilities directory).
2. Wait one minute for the audio circuitry to shut down.
3. Without typing anything else, very quickly strike and release the Backspace key.
4. If you pressed the key all the way, the program should have caused a beep. However, if the audio circuitry goes to sleep, the beep should occur after you have moved your hand off the key. This is because the circuitry takes time to power itself on before playing the sound.
5. Now, quickly strike the Backspace key again. You should notice that the sound is produced immediately as you hit the key, without the delay you just witnessed.
6. Strike the Backspace key repeatedly, to confirm that there is no audio delay. Do this about once every second or two. If you press the key too rapidly, not all of the presses will produce sounds... this behavior is not related to the issue we are testing.
7. Wait another minute for the audio circuitry to shut down, and strike the Backspace key once more. You should again observe a delay between your strike and the sound production.
If you witness delays like this, your audio circuitry is also going to sleep, and you are having the same audio problems as the rest of us. However, either because you are using internal speakers, or because your external speakers don't have the appropriate response, you aren't hearing the same bursts and pops as the rest of us.
Please try this test, and report here. I want to build a list of people who previously couldn't hear the sounds, but still have the delay. This might give us a better picture of the scope of the problem.

Answer 1

Re: 10.4.10 Audio Popping Issues: Information Check with Internal Speakers
Your analysis of what is happening is right on.
The problem on my Intel Mac mini with external Klipsch speakers (two mid-range/high and a subwoofer) is REAL obvious as the system emits a hum like a Spinal Tap amplifier turned up to #11 when 10.4.10 powers down the audio circuitry
Then, if I play a song in iTunes, it first pops and the hum disappears right before playing.
Quite annoying.
Here's what I sent to Apple tech support:
Guys/Gals (OS X Engineers):
Concerning the Snap, Crackle Pop Audio problem in the 10.4.10 update:
Please. Just do the right thing and fix the audio.
There is no need to power cycle the audio subsystem to save .0005 amps on your laptops.
And then to make your Mac mini/iMac/other desktop users have to put up with it when using AC power is ridiculous.
Put the audio subsystem back like it was in 10.4.9 and let the laptop battery freaks looking for mini-amp savings get a "work-a-round".
Crikey!
Mac Mini 1.83 Ghz Intel Core Duo 1GB RAM   Mac OS X (10.4.9)   20 Years of Microsoft-Induced Grey Hair