Optimizing OS X and Mac mini Hardware for Audio

[Yoder]

As per request, I have created this thread so that those who would like to build their own audio server can do so. When I first heard of Mach2 Music and looked at their site, I began entertaining ideas on how I could do the same to my Mac's without handing over $399 for someone to do it for me. In the last few months I have been addressing this problem of mine, and have learned a lot. For example, there is one device out there that you put your mini in to protect it from EMI/RFI. After reading the specs on the mini case and the acoustic characteristics of the metal used then it was a simple deduction that such devices are nothing more than audio snake oil. I have learned that the best hardware modification one can make for the money is to build or buy a quality C7 power cord.

My experience with OS X began about seven years ago. I currently maintain a network of seven Mac's in my household, and three are configured for audio (one Lion and two Snow Leopard). The primary audio mini is running Amarra. Prior to retiring this year, I maintained a lab of 32 iMac's for six years (G5 towers, eMac's, then iMac's) and was confronted with every type of hardware/software/OS problem one could face after they had been toyed with by bored adolescents (high school.) I continue to learn the OS, and imagine that there are many out there who have something to teach me. For this thread I invite lively dialog based on objectivity, and I solicit any suggestions on how I can improve/add to the page below. Let's pick each others brains.

The page title is: Getting the Most Out of Your OS X Music Player. http://www.co-bw.com/Audio_OSX_Optimal_Audio.htm I have a lot of script commands, which for those who are new to OS X but remember the days of DOS, hey basically work the same as DOS shell commands. There is one large script which could be run as a "batch file" in OS X, but more importantly almost everything can be done via the System Preferences. I have inserted images of most of the things I do in the System Preferences, but have not include the last batch of screen shots (I was playing with disabling the Spotlight and wiped the Spotlight index out and it is still rebuilding. Ever try to find a file on over 4 Tb of storage with no index?) I have also included some links to some utility software that can do many of the tasks for you. The bottom line is you have four options: 1) go the hard (Brave Heart) route and play with the terminal and write some scripts, 2) go the fairly easy and error proof way and use System Preferences, 3) use the easy, but possibly dangerous route of using third party software, or 4) pay Mach2 $399. Either way the results will basically be the same.

The link again: http://www.co-bw.com/Audio_OSX_Optimal_Audio.htm

[InfernoSTi]

Nice write up!  That is an easy and direct way to get better sound out of you Mac Mini.  I think it would be a great first (and for many, last) step in creating a really excellent sounding music server.  

I have never been impressed by iTunes and would think that folks who take these steps would benefit from some of the inexpensive and effective programs.  I preferred the simplicity of Decibel (and use Max to rip my CDs).  I really thought the sound quality was a step up from iTunes.

John

[Yoder]

Here is something to play with. Last night I opened the Activity Monitor and started shutting down various processes to see what effect they would have while playing Amarra. If anything trashes the system then a simple reboot will fix the problem. I was impressed with how little of the actual CPU was being used by Amarra. It looked like it was in sleep mode. I did discover some apps that must start via the Library, which is hidden. In the library are all of the plist files and most need to be deleted if any software is manually uninstalled. Don't know if CCleaner does it or not. Unfortunately, the only way to get into the user Library is to use the script code in the above link.

[Yoder]

Last night I played around with OS X for a while.

Using a command found on the page above:

defaults write com.apple.finder AppleShowAllFiles TRUE

I was able to gain access to the root/system. If you go looking around you will find all kinds of crap. I am sure that this is the OS code that Mach2 speaks of when they say they delete 1.8 Gb of code. The actual OS is only 3.8 Gb in size.

Also, if you enter the following into the terminal you can go in and clean-up your Library/Preferences (I had a couple of Apogee pop-ups that I could not get rid of until I went here.)

chflags nohidden ~/Library/

[Yoder]

Lion does allow the user to use 24-bit 96 KHz as an output via the Audio MIDI Set-Up. As I have been saying, the problem with most Lion USB audio is the result of the drivers. Personally, I think that it has something to do with whether the OS is running in 64-bit mode or not. When I was running Snow Leopard all went well with my E-Mu 0404 until I started booting up into 64-bit mode. SL does not go into 64 bit mode by default, but must be told to do so. Here is a link showing how: http://www.co-bw.com/Mac_OS_64_bit.htm I called Creative Labs and M-Audio to find out what was going on, and they said that 64-bit is not supported yet. M-Audio eventually said it was but you had to buy Pro Tools.

My guess is that this is the same problem that people were experiencing when using USB devices with Lion. Lion is native 64-bit. Furthermore, it has been implied that I do not know what I am talking about when I say that Lion runs in integer mode.

, as far as Liion and integer mode -- if Rob Robinson -- formerly of bell labs and who wrote PureMusic (and who also uses double precision 64-bit fp in his internal format when needed( says that integer mode does not work in Lion, I trust he knows what he's saying.  In fact, you are the first person I've ever seen that claims that integer mode is available in Lion.

Here is what Rob Robinson really said about Lion and integer mode, and as I have been saying it has everything to do with the USB devices. The discussion was the result of PureMusic not working with various DACs while running Lion when Lion first came out. Again, Lion does show 16, 20, and 24 bit integer mode in its Audio Midi Set-up. Ironically, this article was one of the first I read that pointed out the USB driver problem when using integer mode.

Rob Robinson says:

"There appears to be a bug in the Format display of Audio MIDI Setup that for some devices, when set to a nonmixable integer format, indicates a 16 bit stream, despite deliberately selecting a 24 bit stream with the player software. This behavior can be confirmed by using HALLab to set the device stream to a 24 bit nonmixable stream, and observe a putative 16 bit stream in AMS. However, the stream is 24 bit, otherwise would sound like noise if a device that was expecting packed 16 bit audio was sent packed 24 bit.

Keep in mind that Apple does not require audio devices to support nonmixable integer streams and consequently the Apple hardware and OS haven't been rigorously tested by Apple in this mode. It is not necessarily guaranteed to function as flawlessly as non-Integer mode.

There is a known problem involving the built-in USB ports on some Mac machines, which causes clicking on the output in Integer mode. I don't have a list of which machines do or don't have the bug. (The Mac Pro does, for instance, but this may be fixed by using a USB PCIe card; confirmed with a Sonnet Tango PCIe FireWire 400 / USB 2.0 combo card.) We have diagnosed this Gordon Rankin

[ralph]

to monitor in real time what processes are running and what resources are being used use the command "top"
to exit top and return to bash or whatever use control c

[ralph]

to kill a process, use the command "kill ###" where ### is the process number

[Yoder]

to kill a process, use the command "kill ###" where ### is the process number

You can find the process number in the Activity Monitor (PID). You can also quit the process to see if it has any affect on the system, and if it does then just do a re-boot. Also, if it is a process that will have a detrimental affect on the OS then the Activity Monitor will warn you. Find what processes you do not need...you will need almost all of the root processes...then go into the Terminal and kill it. It will then remain inactive until you enable it via the Terminal.

[ralph]

On the other hand, looking at the load on the processor,memory and disc accesses, how much of this is really necessary?

Just a thought

By the way, I use a one year old MBP. Or sometimes my Mac pro if working in my office/studio

Ralph

[Yoder]

On the other hand, looking at the load on the processor,memory and disc accesses, how much of this is really necessary?

Just a thought

Yes, the Activity Monitor is quite an eye-opener. I think you bring up a very valid point--how much is really necessary? I play with the AM all of the time and running i7 with 4Gb on my mini, it hardly uses any of the CPU or RAM when I am running Amarra and iTunes. There are some things you definitely do not want to run while playing audio or even have in the background (Firefox, eyeTV, etc.) But, if you are just running your audio software, and given the fact that the i7 is capable of hyper threading (not true with i5) then you have plenty of resources. If one has an older system with limited RAM then you want to get rid of the various apps that they suggest, but with the new hardware then the software barely makes a dent in system resources.

Have you taken a look at the various things in the system? There is definitely some trash in there that can be gotten rid of, and another resource hog/problem area is the users/Ron/Library/Preferences Get rid of some of those plist and you really trim things down. When things go buggy, this is where I usually start especially when using older software.

The 64-bit kernel is also another big asset with Lion, but then a lot of USB drivers hit the shitter.

The bottom line is that I think one could use that page of mine http://www.co-bw.com/Audio_OSX_Optimal_Audio.htm (I still need to add a few things), go into the system and do some cleaning up, delete some unused apps and have as good a system as the Mach2Mac only with $399 left to buy a new Crack and Speedball and some beer! The beauty is that things will only get better, display far more power, and cost a lot less (Moore's Law.)

[Jim R.]

"can do about this. It is a hardware, not software limitation...
the only work-around if afflicted is to turn off Integer mode.""

Bingo!

Now you see the gist of what I was saying -- whichis that you can't count on lion to support your dac in integer mode.  That's all.  And because of that, you are possibly shortchanging yourself in terms of ultimate audio quality -- which is nothing like Lion sucks and you shouldn't use it.

[Yoder]

"can do about this. It is a hardware, not software limitation...
the only work-around if afflicted is to turn off Integer mode.""

Bingo!

Now you see the gist of what I was saying -- whichis that you can't count on lion to support your dac in integer mode.  That's all.  And because of that, you are possibly shortchanging yourself in terms of ultimate audio quality -- which is nothing like Lion sucks and you shouldn't use it.

According to Robinson, there are some DACs that Lion will play with and he lists those DACs. Also, it is limited to USB DACs and the issue it with the interfacing...the audio will play integer mode, but people were reporting a clicking sound. He also listed several USB DACs that played well with Lion, and some that did not. I was using TOSLIK and FW to interface with my DACs and was using integer mode until I went to Amarra. As he said it is not Apple's fault, but implies that it is the result of those who make the DACs not producing functional drivers. I think the issue has to do with the 64-bit kernel. In Snow Leopard my 0404 worked great until I booted it into 64-bit mode and then it hit the crapper. You were insisting that Lion does not support integer mode when in fact it does, it is the hardware that is not working. Certain USB devices may not play well with Lion, but there are many who can attest to using integer mode with it.I do not know where Apple and the various vendors are regarding this, but if I was considering buying a USB DAC and potentially migrating to Lion then I would definitely test the USB DAC on SL 64-bt before doing anything.

[Jim R.]

Well, I tend to avoid dacs that use proprietary drivers -- and this is exactly why -- of course you're asking for trouble goig to a 64 bit os with your old drivers.

You also told me it was impossible to run 64 bit mode on my SL 2010 mini and defended it rather rigorously until somebody pointed you to an artiticle that showed that you were in fact, wrong.  For the record, I have had absolutely zero problems with my SL minis running in 64 bit mode and with every dac I've tried on it.

My recommendation still stands, based on that most people will indeed be using usb dacs, that you cannot count on lion to support integer mode with them.  If you know you want one of the supported dacs, then fine, but I tend to make recommendations for such things generic enough that almost anything anybody chooses will do what I claim...

Done here too.

[Yoder]

You also told me it was impossible to run 64 bit mode on my SL 2010 mini and defended it rather rigorously until somebody pointed you to an artiticle that showed that you were in fact, wrong.  For the record, I have had absolutely zero problems with my SL minis running in 64 bit mode and with every dac I've tried on it.

My recommendation still stands, based on that most people will indeed be using usb dacs, that you cannot count on lion to support integer mode with them.  If you know you want one of the supported dacs, then fine, but I tend to make recommendations for such things generic enough that almost anything anybody chooses will do what I claim...

When you migrate to Lion you do not have any choice but to use 64-bit, and this is where the dual-boot with Snow Leopard issue came in. It would be more accurate if you suggested that those who plan on using a USB DAC should first make sure that it will run with Lion, but given the fact that a lot of the newer DACs are going "driverless," then no biggie. Also, given that every DAC I have seen has an optical input, then the TOSLINK adapter could be used in place of the USB for Lion audio, and thus integer mode and USB becomes a moot point.

Regarding "my telling you" was based on a discussion regarding the fact that the mid 2010 minis did not have 64-bit mode initially, and I was asking/speculating how Mach2Mac made it happen. I also posted a hack that would allow you to use 64-bit mode. If you search Apple Support forums, and the MacRumors forums in the early days when the mini was initially released you will see how this was a major issue on the forums. Consequently, it was shortly after that that Apple sent out a firmware update that allowed for 64-bit mode and the link to this was pointed out. It does not mean that I was wrong, just that my data was a bit outdated.

Also, you did not have to defend yourself "rather rigorously" as I explain above, and like I said I found a hack. You are reading too much into things. Relax, and pay a little more attention to what is actually being said.

[ralph]

Has anyone compared Amarra and clearmusic? What are your thoughts? I use The toslink output from a MacBook pro to a Buffalo.

Ralph