ALC898 audio dropouts on rear jack only

[swashbuckler]

I've just completed my first build following the latest ML CustoMac build guide and everything is working fine, except for one thing: the green rear audio jack which corresponds to "internal speaker" setting in ML has a lot of audio dropouts. This does not happen with the front jack (headphones), which plays just fine, so it's probably not some sort of buffer under-run problem. Inserting a headphone in the front jack will mute the audio coming out of the rear one. With the headphone removed the rear audio gets randomly muted for short periods (half a second or so).

Since I have a dual boot, I should also mention that all audio is working perfectly in Win7 without any such problems.

Has anyone run into this problem? Any suggestions for a fix?

The system has an ALC898 and I did install the corresponding kext using MultiBeast ML edition.

GA-Z77X-UP5 TH
i7-3770k
GTX680
ML / Win7 dual boot

 

[hitINdaGs]

same here! did you find a solution?

 

[swashbuckler]

No. I'm using the front (headphone) jack now to connect to my audio system. Not the most elegant but audio is fine on that one. The problem must be with the muting controls for the rear audio, which I believe are under SW control. I tried disconnecting the front panel from the motherboard to see if there was some 'sense' connection issue but that didn't help. And since it works fine in Win7 I don't think I have a HW problem.

 

[hitINdaGs]

yes, i don't think it's hardware realted. i am using one of the other rear jacks now - i think it's the black one. in system preferences, there are two of those labeled as "line out". the downside is, that the signal does not switch automatically, once you plug a headphone to the front jack.

 

[racerx90]

I have the same motherboard and mine experiences audio dropouts on green rear jack as well. Even when using the black line out jack it happens as well, although not as much as the green jack (but it still happens there as well.) Where I notice it quite a bit is when I'm playing games as the audio dropouts actually causes stuttering to occur during game play.

I'm using the latest patched drivers for non-DSDT systems in the 5.1.1 release of Multbeast. I really wish there was a solution as this is the only thing not working right on this system.

 

[toleda]

I've just completed my first build following the latest ML CustoMac build guide and everything is working fine, except for one thing: the green rear audio jack which corresponds to "internal speaker" setting in ML has a lot of audio dropouts. This does not happen with the front jack (headphones), which plays just fine, so it's probably not some sort of buffer under-run problem. Inserting a headphone in the front jack will mute the audio coming out of the rear one. With the headphone removed the rear audio gets randomly muted for short periods (half a second or so).

Reality check, you are lucky to have any audio as the 898 has never been supported natively. If Windows is better, go with that. I suggest digital audio for zero audio problems in OS X. My 898 system has the best audio performance of all of my systems

My biggest issue is simply with all the testing I do on analog speakers, I do not have these problems. If I can't hear the problem and replicate it, I can offer little help for a solution. It is also important to note these audio issues do not appear to be endemic; some user have issues, many users do not.

The reality is the software was not designed for this hardware, it is appropriate to reset the expectations. You get what you get.

That being said, I'd like someone to try an experiment:
Audio MIDI Setup/Audio Devices/Select Built-in Output/Set Format to 48000.0 Hz 2ch-24bit Integer. Feel free to try other formats.
Reply with results.

 

[Olivier75009]

@ALL
Changing my system definition from iMac 12,2 to MacPro 3,1 stopped the dropouts, popping audio problems.
Maybe should experiment different sys. def. to see what happens.

 

[racerx90]

@ALL
Changing my system definition from iMac 12,2 to MacPro 3,1 stopped the dropouts, popping audio problems.
Maybe should experiment different sys. def. to see what happens.

Already using a MacPro3,1 definition (because of the popping issue with audio when using ALC chipsets.)

I'm out of ideas as audio in Windows works fine.

Also, what BIOS version are you running with? Thanks!

 

[racerx90]

That being said, I'd like someone to try an experiment:
Audio MIDI Setup/Audio Devices/Select Built-in Output/Set Format to 48000.0 Hz 2ch-24bit Integer. Feel free to try other formats.
Reply with results.

Toleda,

First thanks for all your hard work on patching the AppleHDA sound drivers, and on my GA-Z68MA system they've worked flawlessly for me in the past! So I completely understand your point that the we're lucky to even have something that works - definitely no complaints on my part.

Having said that, I did run your tests with 48000.0, 88200.0, 96000.0 and they all experience audio dropouts. I even tried a few combinations of 2ch-20bit/16bit and while some of the settings reduce the drop out frequency, nothing rectifies it. If you have any other suggestions, please let me know and I'd be happy to test it out or provide any additional debugging information for you.

In addition, using the headphone jack's output eliminates the audio drop outs you get with the green and black rear jacks.

Thanks again!

 

[toleda]

Having said that, I did run your tests with 48000.0, 88200.0, 96000.0 and they all experience audio dropouts. I even tried a few combinations of 2ch-20bit/16bit and while some of the settings reduce the drop out frequency, nothing rectifies it. If you have any other suggestions, please let me know and I'd be happy to test it out or provide any additional debugging information for you.

In addition, using the headphone jack's output eliminates the audio drop outs you get with the green and black rear jacks.

Thanks for the test results. In your case, there is no explanation for good sound with green front and bad sound with green rear because the same amp/mixer is used for both. For green rear and black rear, different amp/mixers are used. What happens when you connect the headphones to green rear and black rear.