HOWTO: Guide to Fix your Mac OS X's Speaking Map/Configuration and Allow for AC3/DTS Passthrough, So you Can Hear the Audio from Surround Files as it was Designed to be Heard
DIFFICULTY: Easy, 10-15 minutes
I created this guide with the hope that other Mac users will search for this problem and find this post.
Having trouble playing the audio tracks from your files (e.g., ripped movies or streaming video or DVDs, etc) in the proper surround sound codec that is available on the source file? I am new to the HiFi world, just getting my first TV and AVR in ~10 years last July. Once I purchased five speakers, I almost immediately noticed most dialog was not coming from the center speaker. I understand that some may come from other speakers, but I was dubious that the amount coming from the rear surrounds was correct. I stumbled upon this website from the Perian app
, which is a guide that explains how to setup Perian/Quicktime with true AC3/DTS passthrough. Since that post was written, technology has advanced and Macs now include an HDMI port. Therefore, the post is in need of revision. However, after some tinkering I was able to figure out how to have AC3/DTS passthrough.
On the left side (input) of my Denon AVR 2310’s display, it shows the correct amount of channels based on the source file (e.g., when I watch the Training Day ripped mkv from DVD, it shows 5 distinct channels). The right side of the display shows how many channels are being sent to the speakers (with the Training Day example, it showed 5 distinct channels). As a result, I thought this meant I was getting true 5 channel sound. This is not the case because Apple did not map the speakers properly without a slight tweak in their included software!
This is most likely due to an HDMI format issue and/or bad speaker map from the default audio device configuration that OS X creates for you. This means, your problem most likely is NOT hardware. Read this howto to learn to fix your problem and enjoy movies the way they were meant to be heard!
This guide was created using Mac OS X 10.7.2 on a 2010 17” MacBook Pro for the Denon AVR 2310. I connect the computer to the AVR via HDMI (I use Moshi Mini DP to HDMI Adapter with Audio Support
— careful, other Mini DP to HDMI adapters do not have audio support). The AVR connects via HDMI out to the input of my Sony KDL-Z5100 46" LCD TV (and optical audio out to the AVR). I have a 5 speaker setup, no subwoofer. Other Denon AVRs should work (as should any AVR in general, so long as it supports AC3 and DTS passthrough). I have not tested passthrough with an optical cable, but I assume there would be no issues. Your Apple computer and version of OS X may require you use different settings as presented in this guide. Luckily, everything presented here is easily reversed, and nothing presented will cause any irreversible harm to your computer’s hardware, software, or Denon AVR.INSTRUCTIONS
The key to getting dialog to play (indeed, all channels of the source file to play via the correct speakers in your surround system) correctly, i.e., as it was meant to be heard, is to configure the speaker map on your Mac properly. Follow these instructions, as tested on Mac OS X 10.7.2 (earlier versions may be slightly different):
- 1. You need to enable AC3/DTS passthrough. Go to Applications>Utilities>Terminal. When the application opens, copy and paste the following, without the quotes, then press enter: “defaults write com.cod3r.a52codec attemptPassthrough 1” and “defaults write org.perian.Perian attemptDTSPassthrough 1”. q.v. FOOTNOTE 1
- 2. Connect the HDMI cable from your AVR to your Mac. Make sure you select the proper mode on your AVR so your computer is recognized. Make sure your audio output device in OS X is changed to, e.g., "DENON-AVAMP" (other AVRs will show something else) from the default "Internal Speakers", otherwise, your audio will play through your internal computer speakers. You can quickly switch the audio output device by clicking on the sound icon in the top menu bar, whilst holding option on the keyboard. If you don't see the sound/volume icon in your menu bar, go to the apple icon in the top left, click System Preferences>Sound. Then click the box for "Show volume in menu bar". This will make your life easier.
- 3. Go to Applications>Utilities>Audio MIDI Setup
- 4. On the left side of the "Audio Devices" window that appears, click "HDMI".
- 5. Change Format to 48000.0 Hz and in the dropdown to the right, select “8ch-24bit Integer”. q.v. FOOTNOTE 2
- 6. Now click “Configure Speakers”. In the top right, select the surround system you have. I have 5 speakers (no subwoofer), but I selected “5.1 Surround”. Click each speaker name to make sure sound comes out of the speaker name you just clicked. Adjust as necessary.
That’s it! Now you will hear sound as each track was mixed and it won’t be obfuscated by your Mac! q.v. FOOTNOTE 3 I suggest you double check that everything worked as described by playing a movie file that has AC3 or DTS sound for a minute or two. If there are any unexpected issues, confirm that your source file is using multiple channels by using a video file information analyzer; I recommend VideoSpec
(free- the download is slow, just be patient).
Now my Denon AVR-2310 display will continue to say "MULTI CH IN". Also, the Denon AVR 2310CI will show 8 channels on the input (left) side of its display. This is because of the changes made in Audio MIDI Setup and this will not change, based on the source file you are playing. The output to speakers (right) side of the display will also be fixed, at the amount of speaker channels you have (e.g. 5.1, 7.1, etc). The Denon display will still continue to say "MULTI CH IN".
I really hope my guide was helpful. If you have any questions, feel free to ask and I’ll try my best to help!Footnotes
1 Disclaimer: I am unsure if this is needed anymore. I am leaning towards the idea that this still needs to be done, as the Perian team would have removed the big disclaimer and the link to this site if this part was no longer relevant (this is not the cause for other parts of the guide because it can be variable, depending on your specs and needs). I don’t see the harm in doing this because if something goes awry, you can turn off AC3 and DTS passthrough with the above commands, except you remove the 1 at the end of each command. If that doesn’t make sense, see the guide step #4 I am basing this tutorial of off for the full command. If you have evidence that this step is unnecessary, please provide an explanation and links to support your claim and I will update the guide.
2 You will find a discrepancy in the values I recommend and what the reference link suggests. Specifically, the reference link suggests that you use 2ch-16bit format, but this will not get you surround sound on today's systems. Changing the sample rate to 48 Hz is recommended via the referenced link and since this makes sense, I recommend it here. I think the reason you should now select 8ch-24bit Integer is because when the above guide was written, HDMI was not available on the author's Mac. Now that HDMI is available, selecting 8ch-24bit Integer gives you the best way to configure your surround sound setup, whether you have 5.1, 7.1, etc.. channels. I am not sure if the "8ch-24bit Integer" format value is correct for every situation, however I have tested them and in my situation, the values I give do work properly. Please post your feedback and any changes you made (for reference sake, include the hardware and software used, please!).
3 You may need to configure your preferred media player to take advantage of surround sode tracks, however, there is now no limitation at the OS X level preventing this. VLC works without any further changes, however, some applications have preferences that need to be updated for the fact that you are using an AVR to passthrough audio. In Plex, go to Preferences>System>Audio and Select HDMI in "Audio Output", select your speaker configuration (amount of speaker channels you have) under "Speaker Configuration", select "Dolby Digital (AC3) Capable Receiver" and/or "DTS Capable Receiver", if applicable (yes for Denon AVR-2310CI) and select Default under "Audio Output Device options. Then you can resume your movie taking advantage of your sound surround system. Other video players will be similar.