Why is the volume MUCH lower on my airport express connected speakers when using iMac than from my iPhone?

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TomBevan Author

Level 1

8 points

Why is the volume MUCH lower on my airport express connected speakers when using iMac than from my iPhone?

I have a 2015 iMac, iPhone 6 and second gen Airport Express connected to an Amp and speakers

When I play from Music / Spotify etc from my iPhone the output volume is as you would expect

When I play from my iMac, I have to adjust the volume on the Amp, and the iMac up, right to the top

This suggests there is an output issue with the iMac

That said, the internal speakers are fine, the output to headphones is good and it works well over Bluetooth to another set of speakers

Any suggestions for a fix would be great

iMac, OS X El Capitan (10.11.4), iPhone6, Airport Express (2nd gen)

Posted on Apr 30, 2016 2:18 PM

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Answer 1

Tesserax

Level 10

148,435 points

Apr 30, 2016 3:15 PM in response to TomBevan

On your Mac, iTunes uses a QuickTime CODEC to convert audio files to Apple Lossless, and then, uses AirPlay to send them to the AirPort Express (AX.) In turn, the AX uses built-in software that converts the Apple Lossless to an Encoded Digital Audio format. From there, digital audio is sent to a optical transceiver to convert the electrical signal to an optical one before sending it to the innermost part of the audio port. For analog, the AX has a built-in DAC to convert the Encoded Digital Audio to Analog which is sent to the same audio port ... so there is more processing going on in the background on your Mac than on an iOS device.

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Answer 2

TomBevan Author

Level 1

8 points

Apr 30, 2016 4:30 PM in response to Tesserax

Thanks Tesserax

I ought to have mentioned that this issue did not present on my previous macbook, so not sure why it does with my iMac?

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Answer 3

Tesserax

Level 10

148,435 points

May 1, 2016 8:49 AM in response to TomBevan

It might just be the "nature of the beast." AirPlay supports metadata packets that determine the final output volume on the receiving end. This makes it possible to theoretically send audio data unprocessed at its original volume. Maybe that volume is not the "same" between your Macs?

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