Level Matching and "Robo Mastering"

I ran a poll recently on a couple of home recording forums where I asked people to identify the best sounding master out of 5 possible masters.

I used the following to "remaster" an old song called "Future"
AAMS
LANDR
Masteringbox
A Professional Mastering Engineer
A Master that I produced myself

If you want to do this blind test yourself, check out my web page:
http://www.levityproject.com/home-mastering/mastering/audio-mastering-shootout

Since was a blind test, no one knew which one was which. This made things interesting ... and the results surprised me (sort of). One of the auto services actually got more love than the rest, but the reason why might be more predictable than you would think. I'll explain in a later post.

To complete the test, you will need to download Reaper, which can be found at http://reaper.fm/download.php

There are two Reaper Files in the test. One is not level matched, and one contains masters that I have level matched so they are all the same perceived volume. Try out both and see which master you like best in each.

Once you made your choices, check the results page to see which master you chose! Leave a comment to let me know which you preferred.

Leave a comment here or on the facebook page about which master you chose. I'll explain why you may have chosen it in a future post, but I believe the results will be fairly consistent (as they were when I ran the tests in some audiophile forums).

Photo Source: Wikmedia

Dynamic Range (and Bit Depth Part 2)

Ah the boring technical aspects of audio production. I love it!

So before I talk about Bit Depth, I want to talk briefly about dynamic range.  Dynamic range is essentially the difference in volume from the loudest to quietest portion of audio in a waveform at any given moment. This is also call this the crest factor.

When people talk about the dynamics of a song, they tend to be talking about how loud or squashed sounding a song is. Songs with wide dynamics tend to sound open and airy. Songs with limited dynamics sound punchy and hyped in the best case to squished and crunchy in the worst of cases.

An example of hyped and punchy is Pearl Jam's Dissident. It has a dynamic rage of 8, which is about the minimum level of dynamic rage. Higher numbers are even better in this day and age of volume normalization and web streaming.

An example of squished and crunchy  is none other than Metallica's Death Magnetic. If you look it up on youtube, fans remastered the album from guitar hero stems and it sounds way better than the PRO master! The below video shows the difference between the retail version and the less squished guitar hero version. The difference is stark!!

It pains me so see a lot of Christian recording artists and Worship artists becoming victims of the loudness wars. At work, we sometimes put on Praise 101 and I can stand it for about 30 seconds. Everything is hyper squashed and distorted. Ugh!

All recordings have a dynamic range before mastering, and it's the job of the mastering engineer to decide if the dynamic range is well suited for the song and the album, or if the dynamic range needs to be increased (made quieter) or reduced (made louder). Mastering Engineers can do both. Reducing the dynamic range is quite a bit more difficult than increasing it, FYI.

So when someone talks about "squashing the dynamic range" or "over limiting" or "over compression", what does it mean?What we are really talking about is taking the dynamic range that a track already has and reducing it too much. As a rule of thumb, around 8db-10db of dynamic range is plenty good.

Here's to your music!
Ryan

Sample Rate

At the precipice of the home recording revolution, there was one sample rate: 44.1khz. And there was essentially one bit depth: 16-bit. Before that, there was 8-bit, and very low sample rates (less than 44.1khz). Now days, audio semi-pros and home studio folks are being pushed the line to record at the highest possible sample rates. 

Before you reach for your settings and crank up your sample rate to 192khz,There are some things you should know about sample rate

This website gives a good overview of sampling theory. http://people.xiph.org/~xiphmont/demo/neil-young.html

 

Pay special attention to the inter-modulation section of the website:

 

If you're curious about the performance of your own system, the following samples contain a 30kHz and a 33kHz tone in a 24/96 WAV file, a longer version in a FLAC, some tri-tone warbles, and a normal song clip shifted up by 24kHz so that it's entirely in the ultrasonic range from 24kHz to 46kHz:

• Intermod Tests:
  
  • 30kHz tone + 33kHz tone (24 bit / 96kHz) [5 second WAV] [30 second FLAC]
  • 26kHz - 48kHz warbling tones (24 bit / 96kHz) [10 second WAV]
  • 26kHz - 96kHz warbling tones (24 bit / 192kHz) [10 second WAV]
  • Song clip shifted up by 24kHz (24 bit / 96kHz WAV) [10 second WAV]
        (original version of above clip) (16 bit / 44.1kHz WAV)

 Assuming your system is actually capable of full 96kHz playback [6], the above files should be completely silent with no audible noises, tones, whistles, clicks, or other sounds. If you hear anything, your system has a nonlinearity causing audible intermodulation of the ultrasonics. Be careful when increasing volume; running into digital or analog clipping, even soft clipping, will suddenly cause loud intermodulation tones.

Source: http://people.xiph.org/~xiphmont/demo/neil-young.html

In my own system, 44.1khz, 48khz and 96khz have no inter-modulation artifacts. This means that I can realistically work at 48khz or even 44.1khz and still have just as good clarity and quality as 96khz, which is great because it means I can worry less about CPU load!

 

Here's a video of 8-bit music. One of the problems with early digital audio was that it utilized poor down-sampling filters, and probably wasn't dithered, which is why it sounds so washy and awful at times.

 

Here is 8-bit with high sample rates (at least 44.1khz). The difference is pretty stark.

Here's an interesting video that explains in more detail how that Low-fi music worked.