"Line Input" option not showing in System Preferences>Sound ?

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Level 1

8 points

"Line Input" option not showing in System Preferences>Sound ?

I have a flight simulator application for radio controlled aircraft which uses the audio "line input" to input a signal through a cable from the R/C transmitter. Trouble is that the simulator app (CRRCsim) can't access the line in port, and is obviously trying to fly using the mic signal. I have discovered that the "line input" option doesn't even show in System Preferences>Sound unless I open iChat>Preferences and select "line input" there first. Only then will the "line input" option appear in System Preferences>Sound.

This also affects other applications such as Skype or Yahoo Messenger. If I've been using the flight sim, I'm unable to answer a voice chat until I first launch iChat, and then use iChat preferences to select "Internal Microphone". It seems a bit odd that iChat audio preferences should dictate which options appear in System Preferences>Sound, or other applications, even when iChat isn't open. Has anyone else noticed similar problems, or is it just those of us running CRRCsim? It also seems unlikely that a component of CRRCsim would affect the way iChat works with System Preferences, and other apps, but stranger things have happened.

This didn't seem to be a problem when running Tiger, only appeared with Leopard. BTW, my system is as updated and current as you can be when running a six year old G4 PowerBook.

Any ideas for a fix or work-around?

Thanks,

Warren

Vail, CO USA

G4 Powerbook 15", PM6100/66, Mac OS X (10.5.8), 1.67GHz, 250GB HD, 2GB ram

Posted on May 31, 2011 10:13 PM

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Answer 1

Best reply

Ralph-Johns-UK

Level 9

76,789 points

Jun 2, 2011 1:32 PM in response to WVJ

Hi,

I found this post as I was searching for iChat items.

I am not sure I have the answer but I can relate a similar issues with head sets and then it does not make things disappear in the System Preferences.

Anyway it goes like this:-

On Macs with more than one Input for Audio then iChat gets a Microphone Drop down.

To get your Buddy to hear you adequately you have to Select the Mic in System Preferences > Sound > Input and Adjust the volume to be high enough.

You then have to set the same Input device (Mic) in the iChat Microphone Drop Down.

It was discovered first with Blue Tooth headsets and later with others that you have to set the device (mic and Output) in specific order.

If doing it from the start without iChat open you set System Preferences then iChat.

If you have happened to have had iChat open and started from the Microphone Drop down (The same Pane is where you are supposed to Set Blue Tooth devices) - you have to set System Preferences to anything but the headset Mic and then do the same in iChat.

Then - Set the System Preferences to the Headset, "First" and iChat, "Last".

(Repeat if required for Output)

Now in theory you can set the volume for each Input device in System Preferences ready for iChat and then just use the Microphone Drop down to chose which one.

In Practice it pays to make sure both match and adjust the volume during the first Video or Audio chat with the new device.

It may be a question of what is set first. (That was my idea anyway)

Does any other app and changing the Input choice make a difference ?

Photo Booth ? Quicktime Pro if you have it ? iMovie ? Skype itself ?

I had a look here but could not see anything similar listed.

Do you have the latest version ?

9:32 PM Thursday; June 2, 2011

 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb( 10.6.7)
 Mac OS X (10.6.7),
"Limit the Logs to the Bits above Binary Images."  No, Seriously

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Answer 2

WVJ Author

Level 1

8 points

Jun 3, 2011 9:53 AM in response to Ralph-Johns-UK

Ralph,

Thanks for your reply.

While I haven't had time to run through all the permutations, your answer does seem to support my theory that it's a quirk in the OS, and not in a particular application. I don't imagine that Apple will be rushing to update Leopard soon, so I'll not be holding my breath. I'm currently working my way through a book on the Cocoa environment and perhaps the answer will be somewhere in there.

Cheers,

Warren

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Answer 3

Jun 3, 2011 11:51 AM in response to WVJ

Hi,

It does seem that OS 10.5.8 is as far as Leopard is going.

One final thought.
Try Deleting com.apple.audio.DeviceSettings.plist

You will find this one in Hard Drive/Library/Preferences

You will need to Restart the computer as this is a System Side .plist (This will recreate the .plist from defaults and some sound settings will have to be remade)

7:51 PM Friday; June 3, 2011

 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb( 10.6.7)
 Mac OS X (10.6.7),
"Limit the Logs to the Bits above Binary Images."  No, Seriously

Reply

Answer 4

WVJ Author

Level 1

8 points

Jun 3, 2011 12:30 PM in response to Ralph-Johns-UK

Thanks Ralph,

I'll give that a try. I did have a few unexpected shutdowns due to bad solder joint on the power input jack, now repaired, so .plist corruption is a possibility.

Not ready to fiddle with it just now, but I will let you know the outcome.

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Answer 5

Jun 3, 2011 1:05 PM in response to WVJ

For the Points I will wait for further news.

9:04 PM Friday; June 3, 2011

Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"

 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb( 10.6.7)
 Mac OS X (10.6.7),
"Limit the Logs to the Bits above Binary Images."  No, Seriously

Reply

Answer 6

WVJ Author

Level 1

8 points

Jun 3, 2011 3:43 PM in response to Ralph-Johns-UK

Ralph,

It looks like the .plist isn't the problem. After, the deletion and restart, same behaviors.

I also tried having windows for iChat prefs, and System Preferences showing simultaneously. System Preferences>Sound>Inputs would still only display one option at a time, which depended on which option was selected in iChat>Preferences>Audio/Video. When the selection was changed in iChat, the option displayed in System Preferences could be seen to change in response.

I booted Tiger from an external drive, and found the same iChat dominance, except that the Tiger System Preferences>Sound>Inputs window would display both the "Internal Microphone" and "Line Input" options simultaneously. The option highlighted in System Preferences would change, as above, in response to what was selected in iChat.

I also tried logging-in with a different user account, no change. I don't think the issue is important enough to test with GarageBand or Audacity. By the time I run through all the possibilities, I'll probably have an Intel MacBook Pro, and be on to other mysteries.

So, it looks like it's working as designed and we'll just have to wonder why it was designed that way. It's just an insignificant inconvenience. Still, for curiosity's sake, it would be nice to know what's going on and why.

Thanks again, Ralph.

Regards,

Warren

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Answer 7

Jun 4, 2011 11:57 AM in response to WVJ

Hi,

Looks like it is destined to be a mystery for some time.

I can only imagine that the writers of your Flight Sim have used an unusual technique to achieve what they need to do and that something about iChat provides an override.

I did notice on the CRRCsim web site a Screen Shot that said to set the Audio sample rate at 48000

I know that the only place you can normally see this is in the MIDI Audio Set Utility (Applications/Utilities)

The only time I have seen iChat use that rate is when using an Mic in the External iSight.

However this did not seem to cause the Line in or other input to disappear from the System Preferences > Sound. (i.e the System can normally cope with different input devices set to different Sample rates).

You could spend ages on this as you say and still not find an answer.

The CRRCsim site may have a forum you could ask in an see if anyone else uses the Sim the same way and has the same results. (I guess many don't use Skype so they are not interrupted. and those that do may not have looked in iChat.)

7:57 PM Saturday; June 4, 2011

Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"

 G4/1GhzDual MDD (Leopard 10.5.8)
 MacBookPro 2Gb( 10.6.7)
 Mac OS X (10.6.7),
"Limit the Logs to the Bits above Binary Images."  No, Seriously

Reply