Mastered for iTunes at DES Mastering

There are over 250 million iOS devices in the world today connected to Apple’s vast iTunes ecommerce system. Considering the ubiquity of such a digital audio-ready footprint, there’s a fairly strong chance that just about any commercially-released music title will, at some point, be heard on an iPod, iPhone, or iPad. The resulting market of music consumers who want their content with them to enjoy on-the-go, at home or anywhere dictates that professional mastering engineers should plan and monitor the output of their efforts to provide the very best listening experience possible on iOS devices.

Mastered For iTunes - What is it?

During the first quarter of 2012, Apple implemented their new high-resolution encoding process for creating AAC's. (An AAC is what you download from iTunes, and is the iTunes version of an mp3, both being data-compressed audio files.) In order to take full advantage of the improved quality of this new encoding, Apple has released a set of guidelines and tools to assist mastering professionals in delivering optimized source files for this new high-resolution encoding and ecommerce process, allowing the mastering engineer to audition the changes that take place during AAC encoding prior to committing your mix to processing. Apples’s goal is to build awareness of best practices that will help to ensure that consumers have a great listening experience on their mobile hardware. When these guidelines are followed, the music is considered to be "Mastered for iTunes". DES Mastering supports Apple's efforts and has the full set of tools and the knowledge to prepare finished masters for release into the iTunes environment with the best possible quality. 

It All Starts with Tracking and Mixing in High-Resolution

If you have been following our blog, you know that I have emphasized over and over the importance of tracking, mixing and mastering in high-resolution, meaning 24 bit, and preferably 96k, but at the very least at 48k/24 bit. Apple is now requesting that their music partners submit their source files at 96k/24 bit as the ideal in order to take full advantage of their new encoding process.

As we have pointed out in previous posts, this does not mean that you should sample rate convert your 44.1k/16 bit files to 96k/24 bit. This will do nothing for you. Even if you use the best mastering-quality SRC, the resulting 96k file will sound exactly like the 44.1k file, and from most commercially available SRC's the 96k file will actually sound worse than the original 44.1k file due to artifacts and distortions created during the sample rate conversion. 

So once again, here are the important points:

If possible, track and mix at 96k/24 bit. At the very least track and mix at 48k/24 bit. 

If you are mixing 'in the box', do not perform any sample rate conversion. The mix files should be the same sample rate that the project was tracked at. Again, upsampling a 44.1k or 48k mix to 96k will gain nothing, and will potentially lose quality. 

Do as little processing to the overall mix as absolutely possible, and preferably none. This means little or no eq, compression or limiting applied to the stereo master buss. This doesn't mean that you should not eq or compress individual tracks as you see fit - just try to leave the stereo buss clean of any processing. 

Leave headroom in your mix. if you are doing a proper 24 bit mix, there is no reason for the hottest peaks in your mix to exceed -3dBfs, and ideally they will sit at -6dBfs. 

For more detailed info on this see Mixing in Preparation for Mastering Part 1 and Part 2.
Have a professional master your project. Whether you use DES Mastering or not, you should have a mastering professional finish your project. You may have the best mix engineer in the world, but that does not qualify him as a mastering engineer. It is a completely different skill set, and a completely different way of using seemingly familiar tools. Your project should be mastered in a proper mastering room, not a control room, by a mastering engineer, and preferably one who knows how to create the best possible mastered files for downloadable formats. 

The Best Encode Begins with DES and soundBlade

Encoding for any lossy format such as AAC or mp3 benefits from the highest quality source file possible. This is because the end result of the encoding process is a data compressed file that affects the audio quality. To achieve the best encoded result, it is important to start with the highest quality sound possible, such as that derived by DES Mastering using the Sonic soundBlade mastering system. The Sonic Studio Engine (SSE) used in the soundBlade system enables key processing to deliver pristine sound that is free of artifacts that can be caused by other lesser audio engines. Just because a manufacturer works "Pro" into the name of their product does not make it a mastering-quality platform. When Apple creates an AAC from a soundBlade master it will yield the most desirable output suitable for publishing on the vast iTunes ecommerce platform. 

Remastering for iTunes

If you have a back-catalog of music that is already available in the iTunes Store, or that has not yet been released on iTunes, you might consider having DES properly re-master your project for iTunes delivery. This would require you to have your original mix files, and those will hopefully be 24 bit and 48k or above. If you submit your remastered music to Apple, they will perform a series of tests, and if they determine that the proper guidelines have been followed and that there is an improvement over your previous release, this will earn you the "Mastered for iTunes" badge. 

If you mastered with DES at any time over the past 3 years, we more than likely still have your project in our archive, and if you delivered mixes in high-resolution, then it will be a relatively simple process to create mastered high-res files as Apple is now requesting; it would not require a complete remastering. Contact us for details. 

Importing Your Hi-Res Audio to the iPhone/iPad

Again with the hi-fi related post! But if you are in music production, I promise the training of your ear is just as important as any knowledge you have of audio gear and recording techniques. And having a quality system to listen to music on outside of the studio is important.
If you're following my posts detailing how to get audiophile-quality reproduction out of your computer using standard iTunes and other media players, in Part 1 you learned that the iPhone/iPod can play AIF and WAV files at 44.1k/16 bit CD-quality and ALAC files at 44.1k/16 as well as 24 bit. As was explained, you can import the full resolution files, or if you're not interested in the improved sound quality of these files for your casual iPod listening, you had the option of converting the large full-resolution files to 128kbps AAC's on import, thereby allowing much more music to be stored on the i-device, but at the lower sound quality of 128kbps lossy-compresssion. The new Apple OS now gives you the option of converting to 128, 192 or 256kbps on import. If you're using very good earbuds or phones, the converters and headphone amp in the iPhone 3GS and above is just good enough that you can discern a slight improvement in sound of a 44.1k/16 bit ALAC and the 256kbps version, but it is not drastic. Since you normally don't use your iPod for critical listening, and are often listening in noisier environments not suited to critical listening anyway, many would rather have more song capacity than the slight improvement in sound. But you can more easily hear the difference in quality between 256kbps and 128kbps. It's audible even on standard-issue Apple earbuds, and on high-quality buds and phones it's very evident. So this new option is perfect for better song capacity on the i-device with only a negligible loss in quality.
To change your hi-res files on import, connect the iPhone/iPad to the computer and launch iTunes. Hi-light your device in the devices list and the Summary page for your device comes up. Scroll down and under Options you'll see an option for "Convert higher bit-rate songs to: " and a pull-down menu with the different bit-rates. Choose the bit-rate you want, then click the Apply button on the right.
Rumor has it that the headphone amp and converters in the iPhone 5 will be a further improvement, possibly the same as are now in the iPad.

Tracking and Mixing in HD - Important News

As I have mentioned in previous posts, there are more and more positive signs that we are moving toward a new push for high-definition consumer audio - meaning 88.2k or 96k/24bit. It's unlikely that any of the bigs will get behind a new hardware format, as they are still stinging from the failures of SACD and DVD-Audio, but it looks like HD audio downloads and streaming are coming on in a big way.
Mastering engineers have recommended 88.2k as being the ideal sampling rate for production if CD's and mp3/AAC's are to be produced, since the sample rate convertor has to do a simple 'linear decimation' to get from 88.2k to 44.1k after mastering (just divide by two) resulting in a slightly better sounding conversion, and in the HD world no one has reliably been able to discern a sound quality difference between 88.2k and 96k. However, it seems there is a major effort happening to make 96k/24 bit the de facto standard for HD consumer audio, so it's advisable that you should be tracking and mixing at that rate. This is not a huge problem, as on an audiophile system you may be able to hear the slight quality improvement between a 44.1k file downsampled from 88.2k vs. 96k. But regardless, the file downsampled from 96k will still sound much better than if the track was produced at 44.1k from the start.
This all makes a difference in the parts you should have your mastering room cut. In the past, of the clients who delivered their tracks to mastering in HD, only a handful were interested in getting the HD mastered versions back - they were only interested in the 44.1k/16 bit master for CD and digital distribution. Now, you should want finished production masters in both HD and CD quality. That way, if the consumer industry does move toward HD audio you are ahead of the curve and have HD tracks ready to offer. Even if that never happens, and we stay in the doldrums of mp3, for your own archive it is best to have your music in as high definition as absolutely possible. The only downside is having to pay for the mastering room to create a second master in HD. This should not be a big expense because if it was done properly the tracks were mastered in HD anyway - the HD versions just have to be exported and written to a data CD-R or DVD-R. Many mastering rooms keep their projects backed up, so if you did deliver HD mixes, chances are good that your mastering room can still create an HD production master for you.

Part 3 - Making Your Computer an Audiophile-Quality Music Player

Let's get outside the computer and talk about things you can add that will greatly improve the quality of your sound. Everything we've done in Part 1 and Part 2 have cost nothing, now let's see about spending a few kerns. If you want to build a real audiophile system, it's best done in reasonably affordable steps, unless you have an unlimited budget. It's a huge trend now to build a desktop audiophile system around the computer. This allows you to go with smaller 'nearfield' speakers, since they will only be 3 or 4 feet away, and consequently you won't need as much power. There are many ultra high-end manufactures who build outstanding equipment just for this purpose. You can also integrate your computer-generated music into your larger home theater/entertainment system, we'll talk about that as well. The following steps are a great way to start building a hi-end system. 

NUMBER ONE

Get a good pair of headphones. That's the cheapest way to start, and you'll love what you hear just by following the steps in parts 1 and 2, getting a good pair of phones, and plugging right into the computer's headphone jack. The headphones and speakers are the final parts that dictate the quality of what you're hearing, so until you improve them you won't really be able to hear all of the improvement we've already made in parts 1 and 2 as well as other changes I'll suggest. Nothing else that you do to your system will make as much difference as adding a good pair of phones or speakers. 

You don't have to break the bank to get into 'reference quality' headphones, but you do have to approach the $100.00 range. Recommending speakers or headphones is tricky business, because they all sound different, and a person's taste in sound is very subjective. So where you might like a bright, upfront, immediate sound, the next person may like a richer, warmer, more ambient sound, and you are both right - it's personal preference. So here's the point; headphones and speakers are not things you should buy online. You need to go and listen to them for yourself. It doesn't matter what pro or user reviews say about them, it's all about whether YOUR ears like the sound, and in the case of headphones, if they are comfortable on YOUR head and ears. However, you can classify these products in terms of accuracy and detail, and that is what this 'audiophile quality' we've been striving for is all about. So it's important to realize that if you're just getting into hi-end 'audiophile' audio, your ears will improve as you listen to good sound, so don't dumb yourself down. Choose among models that are recommended by audiophile websites as being accurate. Just because a phone is expensive doesn't make it reference quality. And a lot of trendy headphones - like the Dr. Dre 'Beats' stuff - will wow you in the showroom by having thunderous bass, but it is way exaggerated and completely overshadows the important upper mids and highs. Developing an audiophile's ear and taste doesn't mean giving up bass, it means learning that tight, punchy bass is what you've been wanting, not enormous clouds of undefined bass. In headphones, this reference quality starts at around $80.00 going up to $1500.00 and beyond. When you go to stores to compare headphones and speakers, take some of your favorite music with you so you're listening to the same thing in each test. 

I'll make one headphone recommendation, and you can take it from there. The Grado SR-80i at $99.00 is probably the best value in true audiophile headphones. The Grado RS-1's that I use in mastering cost $700.00, and you would probably be shocked at how similar these $99.00 phones sound to them. When you get a quality pair of phones like the SR-80i, don't be hasty. If you pull them out of the box and immediately listen to them, you'll likely hate them as the sound will be rather harsh and brittle. Most quality phones (and speakers) require as much as a 100 hour 'burn in' or 'run in' at medium-loud volumes before they develop their smoothness and richness, so put them under a pillow in the spare bedroom with an iPod and let them play for four or five days before you use them. 

Aside from that, the long standing major brands AKG, Sennheiser, Sony, Beyer and Audio Technica as well as Grado offer outstanding choices. Go listen for yourself. 

NUMBER TWO

There are two components in your computer that are reducing your sound quality. First is the DAC (Digital-to-Analog Convertor). The DAC converts the digital audio to analog so your analog ears can hear it. (We are still carbon-based analog life forms, though they're working on that.) The quality of DAC built into even the most expensive computer may be decent compared to DAC's of 10 years ago, but they fall way short of the quality that is available today. A good DAC will deliver, among other things tighter, punchier bass, snappier, more defined mids, a clearer, more detailed top end, and a larger soundstage, which is the apparent width, height and depth of a recording - it sounds more 3-dimensional. 

The second thing that is degrading your sound quality, if you're listening to headphones, is the headphone amp built into the computer. Like the DAC, Apple or whoever is not going to increase the price of a computer by integrating a super high-grade headphone amp; it is just good enough to get by. Adding a high quality pair of headphones will dramatically improve your sound, but you won't really hear what your phones sound like until you match their quality with a DAC and a headphone amp. 

Another factor concerning the headphone amp - some hi-end headphones are extremely power hungry, and standard headphone amps built into computers and iPods can't even begin to drive them properly. The recommendations I'll make will all have plenty of power to drive these monsters. (The Grado SR-80i's are not power-hungry, btw.) Also most of the combo's I'll mention have standard 1/4" stereo jacks to match hi-end headphones. 

The good news is, there are some superb DAC/headphone amp combinations starting around $100.00. And as a bonus, most of them also have standard analog outputs so you can connect them to your preamp or receiver, or to powered speakers. The DAC's I'll be talking about are outboard as opposed to sound cards that go inside the computer. Outboard DAC's will almost always outperform sound cards that cost twice as much or more, as sound cards are heavily engineered for the gaming market, so you are paying more for FX gimmicks and surround capability than you are for sound quality. 

Now we need to learn a little new terminology. An outboard DAC will have one or more of the three standard consumer digital inputs:

USB - standard USB.

S/PDIF - also referred to as 'coaxial', which uses one standard RCA connector (same as the connectors on your hi-fi) for stereo input, one for stereo output. (Although it looks like a standard audio cable, you should get a specific digital cable for connecting to S/PDIF.)

TOSLINK which is an optical connector that uses fiber-optic cables. A single TOSLINK connector can be both an input and an output. (Like S/PDIF digital cables, TOSLINK optical cables are available at any electronics store including Radio Shack.)

And one final helpful term, if a piece of gear has both an input and an output, this is referred to as an 'I/O'. 

The most convenient way to connect an outboard DAC to your computer is via USB, and most computers will immediately recognize the DAC without having to install any additional drivers. The DAC will show up under System Preferences/Sound as a playback option (Mac). On newer Macs, the headphone jack is also a TOSLINK I/O. If you connect your Mac to your DAC using a TOSLINK cable, the Mac knows it's connected to an optical digital input and not headphones - you don't have to set anything except the sample rate in Audio Midi Setup. (The Mac's volume control does not affect the TOSLINK digital output.)

As you look at my recommendations, remember that for best sound the DAC should support the sample rate of the audio file you want to play. And you have to set the sample rate in Audio Midi Setup (Mac) to match the sample rate of the audio you're playing, just as we learned in Part 2. Also, a 24 bit DAC will play 16 bit audio with no problem, but a 16 bit DAC will cause some distortion if playing 24 bit audio. Newer DAC's are almost always 24 bit.

Most people will be absolutely thrilled with 44.1k/16 bit CD-quality audio once they hear it properly. For them, life is easy, as any DAC will play 44.1k or 48k/16 bit. For those who want to explore the hi-resolution world of 88.2k/24 bit and above, things are a little tricky. Due to a completely half-assed engineering kluge in the USB standard, USB does not support 88.2k digital audio. Granted most hi-resolution downloads on sites such as hdtracks are at 96k, but there are many outstanding releases that are in 88.2k (the amazing ABKCO remasterings of the Rolling Stones catalog 1963 - 1970 for instance) However if the same DAC also has S/PDIF or TOSLINK inputs, they will almost always accept 88.2k. So if you don't want the restriction, and if you have a Mac or PC with a digital output, you probably want to get a DAC with both USB as well as TOSLINK or S/PDIF inputs. You actually don't need the USB connection in that case, so if you find a DAC with TOSLINK or S/PDIF inputs only, you're good as long as your computer has a matching output. Rumor is the USB spec will change fairly soon to accommodate 88.2k, and the better manufacturers will likely offer a retro-fit for your DAC, and in some cases it may be a firmware update that you can download and install yourself. 

This is an interesting time to look at DACs. There are some amazing values in all types of high end gear from China. Where Chinese manufacturers used to be just (very good) imitators of classic audiophile designs, they have now established their own technologies and theories of sound and are creating some amazing audio gear at very affordable prices. 

Here are some suggestions for great sounding DAC's and DAC/headphone amp combos:

Filo E7 $90.00 DAC/headphone amp only, no outputs for connecting to other gear. 44.1k and 48k 16 bit only. USB input only.

Filo E10 $80.00 DAC/headphone amp. 1/8" stereo analog line out for connecting to external gear. USB input only, 44.1k, 48k and 96k/24 bit. Amazing sound quality at this price. Cheaper than the E7 but seem to be hard to find.

NuForce Icon uDAC-2 $129.00 A fantastic value, great sounding DAC and headphone amp. USB input only. Supports 44.1k, 48k and 96k 24 bit. Analog outputs on standard RCA connectors for connection to external gear. 

Topping D2 DAC/Headphone amp $160.00 USB, S/PDIF, TOSLINK and analog inputs, RCA analog outputs for connection to external gear. 44.1k, 48k and 96k/24 bit via USB input, also 88.2k via TOSLINK and S/PDIF inputs. Analog input lets you connect analog gear for headphone playback. Chinese DAC/headphone amp that outperforms other high end combos up to the $700.00 range. 

Fubar IV $269.00 DAC/headphone amp, USB input 44.1 & 48k/16 bit, TOSLINK & S/PDIF inputs 44.1, 48, 88.2 & 96k/24 bit. RCA analog out for connecting to other gear. 

Fubar IV Plus $379.00 As above but upsamples to 192k for even better sound quality from headphone jack or line output.

CEntrance DACport $349.00 USB only, but supports 88.2k as well as 44.1k, 48k and 96k, 24 bit. Headphone only, no line outputs. This may seem extreme for 'just a headphone amp', but even the craziest audiophiles agree this is a real world class hi-definition DAC and amp. Unbelievable since it's so small, and the fact that it is totally powered by the USB port yet sacrifices nothing in terms of sound quality, as in others that give you USB-port powering.

NuForce Icon HDP $449.00 This is an excellent value because it is a preamp as well as a DAC/headphone amp, meaning the volume pot controls the RCA analog outputs when no headphones are plugged in, so it can be connected directly to a power amp or powered speakers as a preamp, and it has standard RCA analog inputs so you can connect another piece of analog gear (a phono preamp would be tasty, for instance). The USB input supports 44.1k, 48k and 96k/24 bit, and TOSLINK and S/PDIF inputs also support 88.2k, 176.4k and 192k/24 bit. 

Audio-GD NFB-2 $450 DAC only, no headphone amp. Another Chinese piece that rivals DACs beyond the $1500.00 range. USB input accepts 44.1k, 48k and 96k/24 bit, S/PDIF and TOSLINK also accept 88.2k, 176.4k and 192k. 

CONVERT YOUR VINYL TO DIGITAL AND MAINTAIN THE ANALOG SOUND

If you have a large record collection, you might consider an ADAC (analog-to-digital/digital-to-analog converter), meaning it can be used to record as well as play digital audio. The ADAC will have standard RCA analog inputs where you would connect a phono preamp or the recording outputs of a receiver or preamp. Like the DAC, these will connect to your computer via USB, TOSLINK or S/PDIF. You will also find many affordable applications for recording your records that will help you remove clicks, scratches, surface noise and rumble. 

The Furutech GT-40B at $525.00 is really an excellent value. It's an ADAC with both analog line inputs AND an excellent phono preamp (MM and MC), as well as a super hi-end headphone amp. This USB-only ADAC will allow you to record (and play) at 44.1k, 48k or 96k/24 bit. Recording your albums at 96k/24 bit, in combination with the superb quality of the convertor, will maintain all of the richness of your vinyl's analog sound.

You will see many 'USB turntables' on the market that have an ADC (analog-to-digital converter) built in, so all you have to do is plug them into your computer and go. They often even include recording software. However, you are getting neither a good turntable nor a good phono preamp nor ADC in these things. If you want to maintain the quality of your albums' analog sound, you need a good turntable, good cartridge, good phono preamp and good ADC.

When you record your albums, you will be creating standard AIF or WAV files, which we learned about in Part 1. Your best albums should be recorded at 88.2k or 96k/24 bit. Others at 44.1k/24 bit will still sound excellent while taking up half the space. As we talked about there, these files will be huge compared to mp3's, AAC's or even CD-quality 44.1k/16 bit files you've ripped from your CD's. So after recording and de-noising an album, you would use iTunes or the XLD utility to convert the AIF or WAV files to one of the lossless-compression formats Apple Lossless or FLAC, after which they will be almost half their original size. And of course you could create mp3's or AAC's if you prefer those for your iPod. 

That is way too much for Part 3. In Part 4 we'll continue this thread and talk just a little about amps and speakers, and options for integrating your computer audio into your larger entertainment center, including wireless options. We'll also talk about software and 'asynchronous' DAC options that will take your system over the top of true audiophile sound. 

Making Your Computer an Audiophile Quality Music Player - addendum

A side note before Part 3 -
In Part 1 we learned how to rip CD's into iTunes and other media players without losing sound quality, and that CD quality and better music files are available on websites such as www.hdtracks.com. You may realize that this means you will eventually have a jumble of music in data compressed mp3 and AAC formats mixed in with your better quality lossless files. That's fine if you occasionally want to mix the two in playlists or shuffle mode for parties, casual listening etc. But some people prefer to keep their iPod-friendly data-compressed music separate from their high-quality files. It is a simple matter to create a whole new iTunes library just for your CD-quality and better files, or for any other reason. On a Mac, hold down 'Option' as you launch iTunes, or on a PC hold down 'Shift'. A dialogue box will open stating that iTunes needs a library, and asks you to either select a library or create a new one. Create a new library in your music folder named 'iTunes Hi-Res Music' for instance.
Now music you rip into this library will not appear in your other library and vice-versa. If you don't hold down 'Option' when you launch iTunes, it will open the last library that it was using. If you want to use the other library, quit and relaunch with the 'Option' modifier.
Of course you can create alternate libraries for any reason - keeping pop, jazz and classical libraries totally independent for example. You can always import music from any library you're not using into your current library by choosing "Add to Library' under the File menu.

Your Home Music Library and iCloud - Important Info

3/6/12 - Big news on this front. Apple is talking about its new 'Adaptive Streaming' technology, whereby music you purchase in the iTunes Store and  'store' in iCloud would be downloaded to mobile devices in the standard iTunes+ AAC format, but in a lossless format to your computer or any device with adequate storage and fast enough internet connection. They have also begun urging their music partners to upload their tracks in 96k/24 bit HD, so this is one more positive sign that we're moving ever closer to HD audio downloads and streaming for the masses. It still remains to be seen whether you can upload music to the iCloud that you're ripped yourself in lossless ALAC, WAV or AIF, but signs still point to no on that. For more details click here.

--- original post below ---
Apple is now offering iCloud, whereby your photos, music, movies, calendars, contacts etc. can be stored in the iCloud and accessed or updated from any of your computers and mobile i-devices. You will see that Apple offers to not only store the music you have purchased from the iTunes Store (they're not actually storing it - it will be streaming from the iTunes Store), but for $25.00 a year will also match music you have ripped from CD's yourself or acquired elsewhere and store (stream) it from the iTunes Store as well. And they brag that it will be in 256kbps AAC, regardless if your files are at a lower rate. The only thing you have to upload is music that is not available in the iTunes Store. But what's 'cloudy' is the fact that if you ripped your CD's correctly as lossless files (see Part 1 of my computer music posts), or if you have purchased hi-resolution music from hdtracks.com etc., they will also be 256kbps AAC's on the iCloud, not the better quality files you ripped. You will have another option to upload your own files, which can be your lossless audio files. You get 5GB of space for free, but the music or TV shows you have purchased from the iTunes store does not count against your space (again since it's not really being stored there), only music, movies, pictures and documents you actually upload counts against your space. So that means 15 hours of music if you've ripped CD's to Apple Lossless files. That's not much, but you could just keep a rotation of favorite music there for access on your remote i-devices or laptop. And you can buy more space - $20/year for 10GB for instance.
If you don't care about better sound quality on your remote devices, then the matched 256kbps AAC files will be fine. And your high quality files will still be on your main computer for serious listening.
Also, for all you pro-audio guys, don't be too hasty. For iCloud you have to upgrade your computer to OSX Lion, and you need to be really sure that your pro audio applications will work on that operating system.

Part 2 - Making Your Computer an Audiophile-Quality Music Player

HOW TO GET THE BEST SOUND QUALITY FROM ITUNES

Now that you know from Part 1 how to import or purchase full quality audio files, the next step is to get the best sound from the basic iTunes app itself. There are settings in iTunes that will degrade the playback quality and should be defeated when you want totally accurate sound. It's O.K. to use them for casual listening, parties etc. if that works best, but this is what to do when you want to hear things right. When all of these steps are followed, iTunes is actually a bit-perfect 16 or 24 bit digital audio player. These steps apply to Mac computers. It is much more difficult to get bit perfect audio from a PC. You need to do these 4 steps and more. For that I'd suggest a google search.

THIS IS WHAT TO DO IF YOU'RE ONLY INTERESTED IN PLAYING CD-QUALITY AUDIO FILES (44.1K/16 BIT)

Most music lovers will be more than satisfied with CD-quality once they rip their CD collection properly or begin purchasing 44.1k/16 bit downloads. These 4 easy steps cover what to do so iTunes itself isn't affecting the sound quality. If you're interested in high-definition audio (48k, 88.2k or 96k/24 bit), you have to do these four plus step 5.

STEP 1 - Launch iTunes, open preferences and select 'Playback' at the top. Make sure 'Sound Enhancer' and 'Sound Check' are NOT turned on, then click 'OK'. The 'Crossfade' feature will not hurt anything if you like it.

STEP 2 - Under the 'Window' pulldown menu at the top of iTunes select 'Equalizer'. Uncheck it, and to be safe set the Preset menu to 'Flat', then close the window.

STEP 3 - At the top of the iTunes screen, set the volume control all the way to the right. If you are feeding the computer's analog audio output jack to your hi-fi system or powered speakers, the computer's volume control should also be all the way up. You should adjust the volume from your system or speakers, not iTunes or the computer. If you're listening on headphones from the computer's headphone jack, or if your powered speakers don't have volume controls, use the computer's volume control, not the iTunes volume control.

STEP 4 - To complicate things, you can also adjust volumes per song or per album. If you have never done this, don't worry about it, there's nothing to undo. If you have made volume adjustments to individual songs or albums, do this: Highlight an album on which you've made volume adjustments and 'Get Info'. You'll be asked if you want to edit multiple songs, click 'Yes', then click 'Options' at the top of the info window. You'll see a slider for volume adjustment. Leave it set at 'None' and check it, then click O.K. All of the songs on the album will be reset for no volume adjustment.

That's it for regular CD-quality audio files. Proceed to Step 5 if you're interested in playing high-definition audio files (48k, 88.2k or 96k/24 bit AIFF, WAV or Apple Lossless).

STEP 5 - Even if you knew that iTunes can play high-definition 24 bit files up to 96khz, there's something devious going on under the hood that you may not be aware of. When you are listening to any audio media player like iTunes, you are listening to an 'audio engine'. iTunes manages your music library, and provides the DSP functions we defeated in steps 1 - 4. But in Mac computers, the audio engine you are listening to is the QuickTime player. The little secret to this is, you need to set QuickTime's sample rate to match the sample rate of the file you're playing. The default setting is 44.1k, the standard rate for CD-quality files. And that's why you don't need to mess with this if all you'll be playing is 44.1k/16 bit files. But if you play an audio file with a sample rate that does not mot match QuickTime's setting, QuickTime does a rather awful internal sample rate conversion to whatever rate it is set for. So if you don't know how to do this, the extra money you spent for 96/24 downloads was wasted - it will sound worse than the same song as an mp3 if Quick Time is sample rate converting it. Here's how to set QuickTime's sample rate:

In your utilities folder launch the "Audio MIDI Setup" app. Highlight 'Built-In Output'. On the right you'll see pulldown menus for setting sample rate and bit depth. Set the sample rate to match the audio files you're about to play and bit depth to 24 bit. When you go back to playing 44.1k/16 bit lossless or mp3/AAC's, it's still recommended to leave the bit rate at 24 bit. As a side note, any mp3 or AAC that you've purchased will be 44.1k. They can be 48k, but that is very rare.

The following screen captures show how good - and bad - iTunes can be depending on preferences and QuickTime settings:

A 48k 24-bit 10kHz sine wave played through iTunes with QuickTime sample rate set to 48k and bit depth to 24 bit, iTunes DSP defeated and volume control at 100%. The tone shows as a pure spike at 10kHz with no artifacts around it. This is a bit-accurate reproduction of the tone.

A 48k, 24-bit 10 kHz sine wave played through iTunes with QuickTime set to 44.1k, 16 bit. All audio energy outside of 10 kHz is due to distortion caused by the QuickTime sample rate conversion and truncation. 

IF YOU WANT THE DETAILS, HERE'S WHY YOU DEFEATED THE FUNCTIONS IN STEPS 1 - 4
Each feature we disabled is a DSP, or Digital Signal Processor. Each of these will degrade the signal quality to one degree or another. The worst offender is 'Sound Enhancer', which is a pretty awful 'spacial expander'. This makes the music sound as though it is coming from outside of the L/R speakers, creating a much larger sound field. Even though it may wow you when you first hear it, it is highly distorted and not at all accurate.

The EQ is the second worst offender. Even quality eq's add phase distortion, and this is not a quality eq. If you have a decent hi-fi system, especially if it's a good analog preamp or receiver, its eq should be much better.

The master volume control, individual song/album volumes and the Sound Check feature degrade the signal the least. But even bringing the master volume down the smallest amount will cause a digital distortion called 'truncation distortion'. This will be most noticeable on mp3's or AAC's, a little less so on 16 bit lossless or lossless-compression audio files, and barely perceptible on 24 bit files. If you want to use the individual song or album volume adjustments, you should still leave the master volume all the way up; a combination of the two will degrade the audio much worse than using only one.

The Sound Check feature is a rather clumsy attempt at matching the volumes of songs between older vintage CDs and newer ones. Any music produced or remastered after 1995 is usually much louder than music released prior to that. This shouldn't matter if you're sitting down to listen critically to an album, just turn it up as loud as you want. But for parties or casual shuffle-play listening it ca be distracting, so that's a good time to use the feature. You'll soon be hearing of a much more accurate method of matching 'perceived' volumes.

That's all for Part 2. Part 3 will address how to improve the quality of your digital-to-analog convertor over what is built into the computer, which is where we really start getting into the audiophile side of things.