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Tips
& Tricks
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How
To Master Your Own CDs April
19, 2003 ~ ASR-XChange, previously hosted by Scott
Hansen, shutdown for good in late 2002. In addition
to RealAudio demo's from ASR-X users, there were a
pair of articles written by 'Cape Canaveral' that
were were of interest to ASR-X users. I've
reproduced those articles here at ASRXCITE. Thanks
to both Scott and Cape for their past
efforts.
Version
1.02 April 1999 All
statements are IMHO. Step
1: Compress. Step 2: 'FreeFilter'. Step 3:
'Ultramaximizer'. That's it! Read on for more
detail. First
Things First: ONLY
WORK ON COPIES. YOU WILL DO IT WRONG THE FIRST
TIME! KEEP YOUR ORIGINALS IN A SAFE PLACE. YOU HAVE
A CD BURNER, DON'T YOU? BACKUP YOUR .WAV FILES!
Forward: No
one fears technology as much as mastering engineers
seem to, and with good reason. With the hardware
and software available to the average home
recordist these days, a reasonably skilled
individual can track, mix, master and release his
or her own CD. And that CD can be as good quality
as any 'commercial' release. Of
course, you do need some experience and talent. But
I will show you some simple steps that you can take
to transform your own audio from dull to great.
Bear in mind, however, that mastering cannot fix
everything, least of all a poor performance. But if
you have a good recording that you want to make
sound like the CDs you buy, it can be done quite
easily. Although
this article assumes you are using a computer for
mastering your project, you may be able to learn
something by reading it nonethelss. This is for the
DIY type: no money, a bit of gear, a bit of
knowledge... and a lot of determination. You
really should have a bit of experience with mixing,
compression, etc., and also a good understanding of
frequencies and EQ. (For example, too much at 400Hz
will sound 'boxy', not enough at 12k and it will
lack 'presence', etc.) There is a difference
between the mastereing newbie and the audio
neophyte. If you really don't know what you are
doing, then take the time to learn as much as you
can. The
first thing that you need to have is control of the
dynamics. That requires the effective use of
compression. There are many arguments as to the
appropriateness of compression. The general
conesensus is that CDs are overcompressed, and for
the most part this is true. After all, the dynamic
range of a CD (92dB or whatever) is quite something
when compared to a vinyl record or a cassette. For
whatever reason, though, the level of a commercial
CD seems to only fall below 10 dB in the spaces
between songs. But
since we want our recordings to sound like the
pro's, we'll leave the overcompression debate to
the engineers. Anyway, here goes: 1.
COMPRESSION If
you know how to use compression, or have a mix that
you know is properly compressed, you can skip this
section. Compression
is simple to understand but complicated to use.
Compounding this is the fact that few of us have
access to the $10,000 studio tube compressors that
engineers do. In fact, that will be one of the
biggest limitations of this whole project:
professional mastering engineers have the best EQs,
the best preamps, the nicest analog two-tracks,
etc. But it is possible to make do; remember- we're
on a budget! Compression
is a form of gain reduction; it makes the volume
quieter when it is triggered. The key is to
understand how the compressor will respond to the
input. All compressors have a threshold setting.
Levels above the threshold will trigger the
compressor. The
ratio is the degree to which the compressor
reduces the volume. At 2:1, 1 dB of signal gets
through for every 2dB of input over the threshold.
The attack and release parameters
affect how quickly the compressor responds to a
signal crossing the threshold and how long it takes
to 'let go'. How
to set your compressor: Proper
compression requires experience. If you have
never used one before, be prepared to spend a long
time learning. And after you think you can use a
compressor, think again. Pros use multiband
compressors chained together to achieve the desired
effect: gently controlling different frequencies.
They're complicated, and it's hard to even tell
what they're doing if you haven't been trained to
hear it. Since we don't have that luxury, only
patience, experience and luck can get the results
we need. One
way of learning what you're doing is to use a
plug-in such as the Waves RCL. It has an orange bar
in the middle that shows how much the gain is being
reduced. Trying to learn how to use a compressor
with a rack-mount FX unit with an inadequte display
is pretty much impossible! Most compressors should
have some sort of means to indicate how much gain
they are reducing. But not all do, or are very
accurate (the RCL is questionalble in that
regard.) Experiment
with the compressor a lot. Try a variety of
settings. Play with all the parameters. Make it
sound bad, then worse, then distorted, then
pinched... and eventually good. It is vital that
you learn how to hear the compression; understand
what it is doing. Be prepared to spend a few weeks
just playing around: you're trying to replace years
of training and experience. If you don't do it now,
you'll be doing it over again later. Or paying
someone else to do it because you've grown so
frustrated (I've certainly been there!). Now,
if your tracks have already been compressed
(preferably by someone who knew how to do it right)
then you probably have decent control of your
dynamics already. It is always best to have the
tracks compressed as opposed to compressing a whole
mix. But a mix can be compressed as well; extra
caution will be required however. Even if you're
tracks were compressed, you may still want to do
the mix. But it is not always needed. What
you want to do is limit the dynamic range of the
recording. It's really best to experiment, because
the settings you need to use will be different for
every piece of source material. For example, if the
attack is too short, the compressor will snap down
on the transients and induce artifacts known as
'pumping'. A general rule is that when compressing
an entire mix, don't use a ratio higher than 4:1.
The point is to control dynamics, not squash
them. Another
good rule is to always compare the compressed
signal to the uncompressed signal. This is easy if
you are using a plug-in compressor or a compressor
with a bypass button (and they all should have
one). If you don't, you may not notice when you
make your mix sound worse. But you sure will after
the CDs are burned. If
you are compressing your whole mix, make sure you
are careful not to compress too much. Generally, 2-
4 dB of peak gain reduction should be enough. If it
isn't, you're not going to get any better results
by upping the compression, becuase the cheap
compressor you're using just isn't going to do the
job. But feel free to try; you never
know... If
your budget allows, the RNC compressor from FMR
Audio has a mode specifically for compressing a
mix, and it works quite well. I believe it is less
than $200. As always, do your research before you
buy. There may be others that are more suited to
your needs: for example the compressor in the
Ensoniq DP Pro has a preset called "What Dynamics?"
which I understand is quite appropriately
named! I
personally find all the plug-in compressors not
quite good enough. But if a pirated Direct-X plug
is all you can afford, well, what can ya
do? Finally,
be sure to check if your compressor is hard- or
soft-knee. A soft knee compressor will compess
signals leading up to the threshold (at a lower
rate) as well as those over it. Therefore, a file
normalized to 0dB will still be compressed even
with the threshold at 0. This can be unwanted, for
example, if you are using the compressor to boost
the gain and don't want any compression. When
compressing, it will usually soften the effects of
the compressor so that it sounds more musical. But
it's important to know when you're trying to adjust
your settings. This
is just a basic guide. You really need to learn by
doing. Remember that all the settings are working
together. If something's wrong, you will probably
have to adjust all the parameters. The threshold is
too low, the ratio is too high, whatever. Sometimes
it helps to look at the waveform in SoundForge to
get an idea of where the threshold should be.
Tweak, tweak, tweak. Generally,
the ratio should be between 1.5:1 and 4:1, 10-50ms
attack, and 200-400ms decay. But I often deviate
from these settings, so don't think they will work
automatically. But the idea is that if you need to
go too far from these, you may have one or more
settings wrong (such as the threshold, which is
always different) Good
luck! 2.
EQ Ok,
so you've got your .wav file and the mix sounds
pretty good,but it doesn't 'sparkle' like you think
it should. There's a wonderfully easy solution for
this: Steinberg's 'FreeFilter'. This plug-in
analyzes the frequency spectrum of some audio and
then applies it to another audio file. So use it
with a recording that sounds good, and is similar
in style and frequency content
(important!) Alternatively,
you could try and do it by hand with a normal EQ
plug-in (such as the 'Q-Metric'), but the results
of FreeFilter are really good enough. As always,
the trick is to listen to what it is doing. There
is a slider that adjusts the amount of change it
applies to your file, so youcan adjust it to suit
your music. Remember,
this won't really fix any bad mistakes. For
example, the lower end of the frequency spectrum is
always the hardest to adjust. But if your mix is
decent this plug can make it sound truly
professional. FreeFilter
is also complicated to use, and you will need some
decent CPU horsepower to run it at highest-quality
on a stereo file. Any PII should do it; you will
definitely need more than a P-150. 3.
LOUDNESS If
you are reading this, it's probably because you're
going crazy trying to make your song sound as loud
as someone else's. Maybe you've burned a CD for
yourself or a friend and noticed that your music
sounds quiet for some reason. Even though your mix
is compressed and the file's been normalized. Well,
this is what you need to know: When
your mix was compressed, the attack was set to let
the transients through so that the music would
sound natural and not 'pinched'. But when you
normalize the file, these transients may be 5- 10
dB louder than the bulk of the music, even at its
loudest passages. Now, transients are important,
but it's important to remember that the human ear
is not as sensitive to the level of the transients
as much as it is to the fact that their audio
content must be there. So,
you need to 'squish' the transients without
destroying them. To get an idea of what this is,
load a track from a commercial CD into SoundForge
or WaveLab, and have a look. See how they look all
square? (Zoom out and you'll see it). That's what
you want to do. But you want to do it as tastefully
as possible. Some
people will tell you that this is wrong, that it
ruins the audio. Well, maybe. But for the last 50
years, all recordings have had they're levels
squished like this because it was necessary, for
example, to get a hot signal onto analog tape or
overcome noise or whatever. Don't worry. Believe it
or not, your audio will sound better when it looks
like this. You
can use the Waves RCL's gain boost for this, but
the best is really their UltraMaximizer. This
sucker really works! You will probably be able to
get 5-10 dB of gain before it sounds like garbage,
which is a LOT. (10 dB is 2x the perceived lodness,
5dB is half that) Well, probably not 10dB, but at
least 5. Now, compare the loudness of your file to
the one you ripped off the commercial CD. Is there
any difference in the volume? How does it sound? If
you've done everything right, it should sound
great! If
your mix still sounds too quiet, but you can't add
any more gain, it's probably the EQ. A lot of the
perceived loudness is EQ, so try the FreeFilter
again. The
Waves help (which you should have read) notes that
it is possible to have a full-strength digital
signal ( -0dB) go through a D/A converter and come
out louder than 'full digital'. This has to do with
"complex digital issues involving levels 'in
between the samples'." They also point out that
most D/A converters have 3dB of headroom to account
for this, so why they recommend you normalize to
-0.3dB I don't know. It may have something to do
with their 'ultramaximizing' process; perhaps it is
more likely to induce such things. Anyway, it's
something to bear in mind. Remember also that you
don't have to normalize before using the Maximixer:
it will certainly do it for you! A
Note About Burning: Before
you burn a CD, make sure that your tracks have at
least one frame of silence at the start. This is
due to the small inaccuracies of track-seeking CD
players exhibit. Burn a CD with a big kick drum in
the first frame or two and you'll hear a giant
'click' due to the attack being cut off. I usually
just add 200 milliseconds of silence at the start
of every file. If you can, read the help files of
more than one burning program; they all seem to
focus on different aspects of the process. And of
course do some web-searching for related
documents. Conclusion: I
spent a long time looking for a good way to do
this, and tried a lot of different things. This is
the one that really works. The only thing you may
still have to address is the balance of your sub-
250Hz content. This is a sticky issue due to the
way most people have their stereos set (ie with the
bass knob maxed AND the loudness on), not to
mention the poor quality of most home stereos' bass
response- 250 Hz is not bass, but your bass knob
may think it is. Experience is the only way to
properly handle this. Sorry! The
room you mix in is also critical for this (nodes
and such). My advice is to give it your best shot,
and try it on as many different playback systems as
you are able. And remember: is it a demo? No one
expects a demo to sound like it cost $100,000. But
you should still try to make it sound like it did!
At worst, it will probably sound like a very, very
good independant CD. Which is exactly what it is,
right? Also,
don't let what the mastering engineers tell you
disuade you from trying to do it yourself. It can
be done. Just be patient and keep at it. The only
people who can hear the difference between the one
you did and the one that was mastered by a pro are
other mastering engineers! Someone who plays your
CD on a boombox will never hear the
difference! If
you do decide to get it professionally mastered,
remember to shop around. If you get a good one, it
will be worth every penny ($400US is not
unreasonable). Just remember that you usually get
what you pay for. The guy with the cheapest quote
probably won't do any better than the job you did!
I've heard a lot that did worse... ask for
references and demos. Copyright
1999 SOMNIOSUS. Distribute freely. Not to be
reprinted for commercial or non-commercial use,
edited or otherwise altered, or sold without the
express (ie non-emailed) permission of the author.
If you want to help a friend please give him or her
this whole article. Thank you. Hey,
how about "what's a 'customer'?". I hope Claude
does sue you. Jerks. |
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