Saturday, December 16, 2006
Name change
So, lo and behold, mere weeks after I created this Blogger Beta page, I was able to convert the old "Frequencies" to Blogger Beta. So, I will repurpose this blog, just as soon as I figure out what I want to do with it. In the meantime, go to http://michaeljohnson0664.blogspot.com if you wish to continue to read "Frequencies."
Tuesday, December 12, 2006
Happy Birthday Bob Dorough!
Today, December 12, is Bob Dorough's Birthday. You may not be familiar with him, but if you have ever heard any of the songs from "Schoolhouse Rock" you know his work. He was the main songwriter and producer for those Saturday morning cartoons. In other words, he is responsible for such classic songs as "Conjunction Junction" and "I'm Just A Bill!" You can also read my recent post about him on my old blog. You might want to also go to www.bobdorough.com and learn more about him, or wish him a happy birthday!
Friday, December 8, 2006
A Brief Explanation of Bit Rate and Dither
This was one of my earliest posts on my old blog, but I thought I should post it here as well. A friend of mine who uses Pro Tools recently asked me about bit rate. This subject, and especially the related concept of dither, is often difficult for my students to comprehend. The following is adapted from my email reply to my friend. I specifically discuss Pro Tools, but it applies to any DAW program.
Of course, you cannot discuss bit rate without mentioning something about sample rate. When you record to analog tape, you are recording a continuous representation of a waveform. That's the nature of analog. However, it is not the nature of PCM digital audio. At a sample rate of 44.1k, you are taking 44,100 individual snapshots of the waveform every second (44,100 samples per second.) This is why higher sample rates are better, because you get a better representation of the waveform. Your sample rate also limits the range of frequencies you can reproduce, but that is another discussion entirely.
Now, when you talk about bit rate, you are talking about the size of each sample. Digital audio is encoded in binary code, which is a series of one's and zero's. So, the bit rate determines how many ones or zeros each sample will have. At 16 bits, each sample is represented by 16 ones or zeros. At 24 bits, then, you have 8 more ones or zeros per sample. As you can probably imagine, the amount of combinations of ones and zeros is greatly increased at 24 bits. Thus, you get a more accurate representation of the sample. You have increased resolution, which ultimately means greater fidelity.
This increased resolution is often more noticeable when it comes to changes in dynamics. For instance, at 16 bits, a fadeout might at some point seem to just fall off a cliff! In other words, you might hear a nice, smooth fade for a while, but then suddenly the signal is gone. At 24 bits, however, the fade might sound infinitely better. In fact, many engineers feel there is a drastic difference in audio quality between 24 bits and 16 bits. You may have correctly inferred from what I said earlier that higher sample rates mean larger frequency range. Similarly, higher bit rates mean larger dynamic range. Therefore, musical styles with greater dynamic range, such as jazz and classical, benefit from higher bit rates. With Rock music, on the other hand, which is often heavily compressed anyway, it may not matter as much.
Now, back to dither. Even though dither does add a small amount of noise to the signal, there is a second algorithm called noise shaping, in which the dither noise is re-EQ'd out of the audible range. However, it is more important to understand the true purpose of dither. When you reduce the bit rate from 24 to 16, you are reducing the resolution of each sample by 1/3, basically truncating the last 8 bits off of each sample. This can reduce the dynamic range, and generally degrade the sound quality. When you add dither, it does something akin to rounding off the last few bits to make up for the 8 bits you are losing. In other words, it is designed to allow you to preserve at least some of the dynamic range and overall sound quality when you reduce the bit rate.
The best way to A/B between a dithered and undithered mix would be to listen to a fade-out. The dithered version should sound smoother.
Of course, these differences are, admittedly, rather subtle, and I do know a few engineers who think it's all hogwash. The ideal solution to this problem is a 24-bit digital audio standard, hopefully at a higher sample rate as well. I believe this will happen very soon.
A few years ago, I had a friend who would do all of his sessions at 16 bits, reasoning that it would keep him from having to worry about bit-rate reduction and dither. I actually bought into this for a while, and was doing the same thing. Then one day I read that Pro Tools does all of it's processing in 24 bits. This means that whenever I was using a plug-in or doing a bounce, even a gain change with a fader, it would increase the bit rate to 24, then go back down to 16. So, obviously, there was absolutely no advantage (and, actually, a big disadvantage) to doing things that way.
Then, as I studied digital audio even more I found out that every audio calculation you do, even in the 24 bit range, briefly adds bits to the end of each sample, then cuts them back off to return to your session bit rate. (I had taken recording classes back in the analog days, so I never learned this until I started teaching it.) That's why, for instance, you can set Pro Tools to use dither for audiosuite plug-ins. The consensus among audio engineers, thankfully, is that, even though there is a big difference in sound quality between 16 and 24 bits, once you get above 24 bits, the differences are much less severe, so these recalculations do not adversely affect the sound quality.
One other thing to remember about dither: Since it does add some noise to the signal, you usually don't want to do it more than once. That's why it should be the very last thing you do while you are performing a bit-rate reduction (such as a bounce to disk operation.)
When mixing an album, it’s best to stay in the 24-bit realm, even when you bounce down to stereo mixes. Then, you should take your 24 bit stereo bounces back into your DAW or mastering program, and apply EQ, multiband compression, limiting, etc. in order to get consistent levels and EQ between each song. Finally, insert dither on the master fader and bounce each song to a 16-bit file. In other words, if you are working on an album or EP project that will be mixed and mastered, you should stay at 24 bits all the way through to the end of the mastering phase.
Of course, you cannot discuss bit rate without mentioning something about sample rate. When you record to analog tape, you are recording a continuous representation of a waveform. That's the nature of analog. However, it is not the nature of PCM digital audio. At a sample rate of 44.1k, you are taking 44,100 individual snapshots of the waveform every second (44,100 samples per second.) This is why higher sample rates are better, because you get a better representation of the waveform. Your sample rate also limits the range of frequencies you can reproduce, but that is another discussion entirely.
Now, when you talk about bit rate, you are talking about the size of each sample. Digital audio is encoded in binary code, which is a series of one's and zero's. So, the bit rate determines how many ones or zeros each sample will have. At 16 bits, each sample is represented by 16 ones or zeros. At 24 bits, then, you have 8 more ones or zeros per sample. As you can probably imagine, the amount of combinations of ones and zeros is greatly increased at 24 bits. Thus, you get a more accurate representation of the sample. You have increased resolution, which ultimately means greater fidelity.
This increased resolution is often more noticeable when it comes to changes in dynamics. For instance, at 16 bits, a fadeout might at some point seem to just fall off a cliff! In other words, you might hear a nice, smooth fade for a while, but then suddenly the signal is gone. At 24 bits, however, the fade might sound infinitely better. In fact, many engineers feel there is a drastic difference in audio quality between 24 bits and 16 bits. You may have correctly inferred from what I said earlier that higher sample rates mean larger frequency range. Similarly, higher bit rates mean larger dynamic range. Therefore, musical styles with greater dynamic range, such as jazz and classical, benefit from higher bit rates. With Rock music, on the other hand, which is often heavily compressed anyway, it may not matter as much.
Now, back to dither. Even though dither does add a small amount of noise to the signal, there is a second algorithm called noise shaping, in which the dither noise is re-EQ'd out of the audible range. However, it is more important to understand the true purpose of dither. When you reduce the bit rate from 24 to 16, you are reducing the resolution of each sample by 1/3, basically truncating the last 8 bits off of each sample. This can reduce the dynamic range, and generally degrade the sound quality. When you add dither, it does something akin to rounding off the last few bits to make up for the 8 bits you are losing. In other words, it is designed to allow you to preserve at least some of the dynamic range and overall sound quality when you reduce the bit rate.
The best way to A/B between a dithered and undithered mix would be to listen to a fade-out. The dithered version should sound smoother.
Of course, these differences are, admittedly, rather subtle, and I do know a few engineers who think it's all hogwash. The ideal solution to this problem is a 24-bit digital audio standard, hopefully at a higher sample rate as well. I believe this will happen very soon.
A few years ago, I had a friend who would do all of his sessions at 16 bits, reasoning that it would keep him from having to worry about bit-rate reduction and dither. I actually bought into this for a while, and was doing the same thing. Then one day I read that Pro Tools does all of it's processing in 24 bits. This means that whenever I was using a plug-in or doing a bounce, even a gain change with a fader, it would increase the bit rate to 24, then go back down to 16. So, obviously, there was absolutely no advantage (and, actually, a big disadvantage) to doing things that way.
Then, as I studied digital audio even more I found out that every audio calculation you do, even in the 24 bit range, briefly adds bits to the end of each sample, then cuts them back off to return to your session bit rate. (I had taken recording classes back in the analog days, so I never learned this until I started teaching it.) That's why, for instance, you can set Pro Tools to use dither for audiosuite plug-ins. The consensus among audio engineers, thankfully, is that, even though there is a big difference in sound quality between 16 and 24 bits, once you get above 24 bits, the differences are much less severe, so these recalculations do not adversely affect the sound quality.
One other thing to remember about dither: Since it does add some noise to the signal, you usually don't want to do it more than once. That's why it should be the very last thing you do while you are performing a bit-rate reduction (such as a bounce to disk operation.)
When mixing an album, it’s best to stay in the 24-bit realm, even when you bounce down to stereo mixes. Then, you should take your 24 bit stereo bounces back into your DAW or mastering program, and apply EQ, multiband compression, limiting, etc. in order to get consistent levels and EQ between each song. Finally, insert dither on the master fader and bounce each song to a 16-bit file. In other words, if you are working on an album or EP project that will be mixed and mastered, you should stay at 24 bits all the way through to the end of the mastering phase.
Friday, December 1, 2006
Art Vs. Greed
Sorry to post a long one, but I think it's an important topic. If you haven't seen the movie Before The Music Dies, point your browser there and either find a screening near you or buy the DVD. I felt like it was a very timely movie, given the state of the business right now. This is not a review of the film, but I want to discuss several points they made.
One of the interview subjects in the movie makes a distinction between the "record business" and the "music business." Another gentleman points out that most of the “people who buy Brittney Spears records are not music fans, they are popular culture fans.” Mention is also made that the upper management at the major record labels know more about the stock market than they do about music.
There were other similar comments, including those of Questlove and Erykah Badu. Near the end of the film, Dave Matthews points out that you might as well go on “Fear Factor” if you are interested in fame and wealth. Otherwise, you should just find a way to do what you love, even if you have to work a day job to pay the bills.
Still, people continue to doggedly cling to the old, greed-based music industry model, despite all indications that it is falling apart all around us. Unfortunately, some of those true believers have settled into academia, and they are filling young minds with visions of large profits even as we speak. I certainly hope that this current crop of “music business” students don’t emerge from four years of college only to find that it no longer exists. I could be wrong, but this latest surge of insane litigation that some of the majors and the RIAA have undertaken looks like a desperate last-ditch money grab before they go down the tubes!
On the other hand, if you are a musician, especially of the “artistic” bent, the world is your oyster! I have firmly believed this for several years, and after seeing the film, I am even more convinced. We no longer need the major labels – they have become irrelevant, and may even die soon!
Here’s my advice for aspiring artists: find an indie label or, better yet, start your own label! Take some music business courses, and even some business courses, so that you can understand the business side yourself. Invest your time and money into getting your live act together, and booking a regional tour. Book a college tour through NACA if you think that would be a good avenue for your music. At each show, get people to sign up for your mailing list so you can let them know when you’re in the area again or releasing new material.
Buy your own recording gear, and record your CD’s yourself. Get a professional to mix and/or master them for you if that is not your forte. Get your myspace page going, duplicate your CD through Disc Makers or a similar service, and send it to CDBaby so you can get it on iTunes. Submit your songs to podcasts and internet radio stations devoted to new music. Join ASCAP or BMI, and make sure you submit your recording to soundscan.
I could go on and on, but I’m sure you get the picture. Of course, you don’t have to go it alone, either. I’m sure you have some good friends who are or were music business majors, and you can set up a partnership with them for a cut of the action!
That brings me to my last point. Whether you are in college or just involved in a local music scene, get to know people and cultivate those relationships. In my 6+ years at Greenville College, I have witnessed the strong community of Greenville graduates in Nashville, who are involved in all aspects of the industry. Many of them, for example, have landed gigs on the basis of a referral from a former classmate. It makes sense to build friendships and avoid burning bridges, because that relationship might help you out one day!
One of the interview subjects in the movie makes a distinction between the "record business" and the "music business." Another gentleman points out that most of the “people who buy Brittney Spears records are not music fans, they are popular culture fans.” Mention is also made that the upper management at the major record labels know more about the stock market than they do about music.
There were other similar comments, including those of Questlove and Erykah Badu. Near the end of the film, Dave Matthews points out that you might as well go on “Fear Factor” if you are interested in fame and wealth. Otherwise, you should just find a way to do what you love, even if you have to work a day job to pay the bills.
Still, people continue to doggedly cling to the old, greed-based music industry model, despite all indications that it is falling apart all around us. Unfortunately, some of those true believers have settled into academia, and they are filling young minds with visions of large profits even as we speak. I certainly hope that this current crop of “music business” students don’t emerge from four years of college only to find that it no longer exists. I could be wrong, but this latest surge of insane litigation that some of the majors and the RIAA have undertaken looks like a desperate last-ditch money grab before they go down the tubes!
On the other hand, if you are a musician, especially of the “artistic” bent, the world is your oyster! I have firmly believed this for several years, and after seeing the film, I am even more convinced. We no longer need the major labels – they have become irrelevant, and may even die soon!
Here’s my advice for aspiring artists: find an indie label or, better yet, start your own label! Take some music business courses, and even some business courses, so that you can understand the business side yourself. Invest your time and money into getting your live act together, and booking a regional tour. Book a college tour through NACA if you think that would be a good avenue for your music. At each show, get people to sign up for your mailing list so you can let them know when you’re in the area again or releasing new material.
Buy your own recording gear, and record your CD’s yourself. Get a professional to mix and/or master them for you if that is not your forte. Get your myspace page going, duplicate your CD through Disc Makers or a similar service, and send it to CDBaby so you can get it on iTunes. Submit your songs to podcasts and internet radio stations devoted to new music. Join ASCAP or BMI, and make sure you submit your recording to soundscan.
I could go on and on, but I’m sure you get the picture. Of course, you don’t have to go it alone, either. I’m sure you have some good friends who are or were music business majors, and you can set up a partnership with them for a cut of the action!
That brings me to my last point. Whether you are in college or just involved in a local music scene, get to know people and cultivate those relationships. In my 6+ years at Greenville College, I have witnessed the strong community of Greenville graduates in Nashville, who are involved in all aspects of the industry. Many of them, for example, have landed gigs on the basis of a referral from a former classmate. It makes sense to build friendships and avoid burning bridges, because that relationship might help you out one day!
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