MP 1,1-5,1 No line-in audio (cMP 5,1/mid-2010)

[macstatic]

For some reason I'm not hearing the audio coming in from the rear line-in jack of my cMP (mid-2010/MacOS 10.13.6).
I've checked the Sound preferences and set INPUT to "Line in" (the meter definitely shows audio coming in) and OUTPUT to "Internal speakers".
The funny thing is that I do hear the alert sounds and whatever comes from the web browser. And using the Audio MIDI setup app's "Configure speakers" I can again confirm that the internal speaker is working, but not what comes in from the line-input.

 

[barbu]

What other options are available under the Format menu ?

 

[arw]

If I understood you correctly, that‘s not how LINE IN works. It‘s not a sound pass-through or amplifier to LINE OUT.
You need a program (like Quicktime) to record from line in, then you should automatically hear it through the default audio output.
Surely there is a program to achieve what you seek, but I don‘t know any. (Maybe take a look at Soundflower)

 

[barbu]

Yeah agree with above. You need to interconnect your devices to hear the input thru some output. Soundflower can help

 

[macstatic]

You're both right!
I tried it with a couple of audio recording apps and there I noticed a "monitor" type button which appeared while recording, so apparently you need an app with that feature while recording (or not hear anything at all, but see the audio coming in (the app's VU meter) or play back the recorded audio afterwards.
Is this to prevent feedback?

Isn't Soundflower defunct and replaced with other similar tools such as BlackHole?

 

[MarkC426]

Do you have it selected on the Sound panel in preferences?
Have you checked if the optical input has a light on, which would be active.
It can be stuck sometimes.

 

[macstatic]

Do you have it selected on the Sound panel in preferences?
Have you checked if the optical input has a light on, which would be active.
It can be stuck sometimes.

I got it working (you need to use a recording app with input monitoring turned on).
Like the two previous posters said, the line-in input doesn't simply pass on audio to be heard through the speakers (or audio interface either apparently -I tried that as well).
I'm wondering if it's to prevent audio feedback.

Good idea to check the optical light. I didn't check it, but I've had a look now -it's not inside the 3.5mm line input jack (like some audio recorders do) but a separate audio input above it.

 

[mattspace]

I got it working (you need to use a recording app with input monitoring turned on).
Like the two previous posters said, the line-in input doesn't simply pass on audio to be heard through the speakers (or audio interface either apparently -I tried that as well).

Rogue Amoeba used to do a one trick app that simply did the live passthrough, but they've retired it in favour of putting the feature within their more advanced apps.

I'm wondering if it's to prevent audio feedback.

It's a basic anti-piracy measure, to prevent the machine being effortlessly used to re-record DRM'd audio via the "analog hole".

 

[macstatic]

Rogue Amoeba used to do a one trick app that simply did the live passthrough, but they've retired it in favour of putting the feature within their more advanced apps.

Thanks to this thread I now know this "feature" and that I need to use recording apps that support it.
After rechecking all the sample rates, using the correct audio input and output, zapping the PRAM, trying it from another Mac user-account, rebooting, deleting the audio related preferences etc. I really couldn't understand why I couldn't hear what came into that input. Seems like Apple has been keeping this a "secret" as well -there was nothing about it in the Mac Pro user manual either.

Rogue Amoeba have had several nice and interesting audio related tools throughout the years (I believe even some free ones, trying to think back to my MacOS 7,8 and 9 days).

It's a basic anti-piracy measure, to prevent the machine being effortlessly used to re-record DRM'd audio via the "analog hole".

Ah, I see.
Irritating with stuff like that when you just want to use it for other, fully legal things. Oh well.

 

[MarkC426]

I don't know what you are recording as a source.
But I have been using GarageBand to record MY vinyl, both with a pre-amp mixer into line-in and with a USB turntable.

 

[macstatic]

Cool! 👍
I'm actually testing it out with a sound generator app ("Oscillator") from an iPad in order to figure out how to mix audio from different sources. The iPad app sends out a continous test-tone which is great for this sort of thing.