The Home Recording Quality
Syndrome |
| The first few home recordings that are made
initially sound very good to the new recording enthusiast. When you play it
for family and friends, they will join in the chorus of "sounds great."
The fact that you are producing recorded product at home will initially be so impressive
to friends, family and yourself that you'd hear any sound as good. Somewhat later it
is likely that reality will set in - you will begin to notice that your home recordings
don't sound all that good compared to released CDs you can buy in the record store.
The quest will be How do I correct my poor recording quality that I get at home?. This
is the subject we are addressing with the Home Recording Primer.
|
| If you were demanding better home recording
sound quality and you used the information you read in Part 1 of this article, you got a dramatic improvement in your
sound. You started isolating instruments from each other and reduced the
"basement ambiance" in the pickup of the instruments you recorded. You got
the right microphone on the instrument, the one that captured all of the instrument's
sound, and you put it in a better place or at a better angle to get the sound needed on
the recording. |
| Now we are presenting Part 2 of this primer
where we will help you use the control room equipment better and get another significant
boost in your home recording sound quality. |
| The Levels In The Control Room |
| The microphones on the instruments convert
the sound waves into an audio signal that gets plugged into microphone inputs of the
recording console. Electric instruments (such as the electric bass) and electronic
instruments (such as synthesizers and drum machines can also be put into the microphone
inputs by use of a direct box or level-matching transformer. These
electric/electronic instruments already put out an audio signal, but at a much higher
level called line level. These instruments can alternately be plugged into
line inputs of the recording console. |
| Once you are dealing with sound in its audio
signal form, you will have to be concerned about levels. How carefully you set
levels will be a big determining factor in how well your recording turns out. The
rule about levels is called the First Control Room Rule: |
FIRST CONTROL ROOM RULE |
THE AUDIO INPUT SIGNAL TO ALL
CONTROL ROOM GEAR SHOULD BE AT OPTIMUM LEVEL FOR THAT PIECE OF EQUIPMENT |
|
|
| If an input receives too high of a signal,
part of the audio waveform is "clipped" by the equipment's input circuits and
you would hear distortion. Every piece of audio equipment also has noise which
sounds like a low-level hiss. The higher your signal is, the less you hear the hiss
caused by the equipment noise at the equipment's input. So the optimum level is
almost as high as you can get it without signal clipping. I say "almost"
because you need to leave a little room for an unexpectedly loud peak by the musician
because the instrument was struck or plucked harder on one note. |
|
Figure
1 - "Optimum Levels" |
|
| The two pieces of equipment that you usually
need to watch for correct input levels are the recording console and the audio recorder. |
| The Console: |
| Almost all recording consoles and mixers have
overload lights that flash when the incoming signals are too high. You should have
the musician play the instrument - request that the "loudest passage" be played.
Set your input ("microphone") gain so that this light does not flash but
the control is as high as possible without flashing. Later on in the processes
the lights may flicker slightly (which is OK). The console can really take a level
where the overload lights flicker, but you initially set it up so that they don't and use
the additional level that could be tolerated as "headroom" (a margin allowed for
signals to get slightly louder without clipping the signal). |
| On electric and electronic instruments, you
usually get the best result when the instrument's volume control is set to maximum and the
signal is set for the proper strength using the console's input level control. |
| The Audio Recorder |
| Most tape machines and other audio recorders
today don't have an adjustable input level. The meters on the recorder read input
level during recording and read playback level during playback of the tape. If the
recorder is setup properly and the proper tape is being used, the meters will read the
same level during recording and playback. |
| The console also has output meters that read
the level of the signals being sent to the recorder. Usually the console output
meters and the recorder's meters should read the same. If the recorder does have
input level controls ("record level controls"), the best place to set then is to
the place that makes the console and recorder meters agree on levels. |
| Sometimes, usually when you have an analog
console with a digital recorder, you will have a situation where the the console and the
tape machine meters don't read the same and sometimes they are father apart on certain
instruments. In these cases you should pay attention to the recorder's meters
rather than the console's meters. |
| Analog Vs. Digital |
| When you have analog recorder, you set your
console output levels so that the recorder's meters reads "0" on the loud peaks.
For most signals the recorder can record above zero without severe distortion;
this extra capability becomes your "headroom." Analog tape can't
take loud very high-frequency signals. When recording things like cymbals by
themselves, set the levels to read "-6" |
| When you are sending to a digital recorder,
set your console output levels to "-6" because the digital recorder can't record
above "0" by any amount without severe distortion.
Recording at "-6" gives you the headroom that you need
to properly record an unexpected peak. |
| Routing The Console |
| After you get the audio signals into the
console at the right level, you need to route the signal though to the track to record the
instrument. |
| Input Selection: |
| For recording, the microphone signals must be
received by the console's main inputs. On many consoles, there is a Mic/Line Switch at the
top of each strip. Selecting "Mic" means that the microphone signal will
be received for that channel. This is the position used for the recording session.
The "Line" position can be used to pick up the outputs of electric and
electronic instruments during recording. On the majority of the analog
consoles this line input is also used during the mixdown process (which is explained
later) |
|
Figure
2 - Input Selection Switches |
|
| On the majority of the consoles, there is a
means of sending 48 Volts out of the console to power condenser microphones. There
can be individual switches on each input or there can be one central 48-volt switch.
Activate the 48-volt switches for the channels that have condenser microphones or activate
the central 48-volt switch if any condenser microphones are being used. Always turn on the
48-volt power after the microphones are plugged in and turn off the 48-volt power before
disconnecting the microphones. Plugging in or disconnecting a microphone with the 48-volt
power turned on will send a burst of energy through the channel (a "pop") that
can be loud enough to damage the speakers. |
| Direct Routing: |
| Direct routing means that one
microphone signal is sent to one track. On 95% of the consoles, the microphones are sent
to the same track number as the microphone input number. Lets say that microphone #2 was
on the snare drum. Activating the direct routing switch on strip 2 will cause the
snare microphone signal for input 2 to be sent to track 2. The snare will be
recorded onto track 2. |
| Recording Busses: |
| A Recording Buss is a wire that is going to
one or more track outputs of the console. The recording buss can accept a signal
from any console input. When you need to send more than one signal to one
track, you must send all of them to the recording buss that feeds that track. |
| For more than a decade, manufacturers have
been configuring smaller consoles with 8 recording busses but designing them for use with a
16 track (or even 24 track) recorder. Each recording buss will feed to 2 or 3
recording tracks according to the chart below. |
CONSOLE
RECORDING BUSS |
POSSIBLE
RECORDING TRACKS |
1 |
1, 9, 17 |
| 2 |
2, 10, 18 |
| 3 |
3, 11, 19 |
| 4 |
4, 12, 20 |
| 5 |
5, 13,
21 |
| 6 |
6, 14,
22 |
| 7 |
7, 15,
23 |
| 8 |
8, 16,
24 |
| BLUE
NUMBERS INDICATE INPUTS THAT HAVE DIRECT ROUTING |
BLUE
NUMBERS INDICATE THAT THE BUSS NO LONGER RECEIVES THAT CONSOLE SIGNAL |
|
| Usually at the top of the console strip,
there will be rows of switch buttons with numbers. Pushing one of these numbered
buttons will send the microphone signal to the recording buss of that number. Which
track receives the buss signal for recording is dependent on which track is put into
record and what tracks have had direct routing activated. |
| The recorder no longer receives a buss signal
when there has been a direct routing to that track. Thus using direct routing on
console channels 1-4 means that recording busses 1-4 no longer go to tracks 1-4. |
| Let's say that you have 3 singers that are
plugged into inputs 13, 14 and 15 and you want to record these singers on track 10.
You would push button #2 on each of the input strips that had the microphone signal (#13,
#14 & #15) - per the above guide. If a direct button is pushed on a strip, that
buss is "locked out" and can't be used. In our above example, the direct
button was pushed on strip #2 to record the snare; the microphones in input 13, 14 &
15 would not reach track 2, even though you pushed button #2 on each of these input
strips. |
|
Figure 3 - 8 Buss
Console Routing |
|
| Setting Levels While Using Busses: |
| Procedures on getting levels change slightly
when you are routing several microphones to one track. The input levels, set with
the overload light, is the same. To set console levels, you set the microphone
levels for each of the inputs one by one. When doing this the buss master level
should be all the way up, the channel fader should be at about 75% to get "0"
level on the console meters. |
| After you check all of the individual levels,
you have all of the musicians perform. Adjust the individual channel faders so that the
mix of the musicians is correct (usually equally loud). If the console meter reads too
high, reduce the buss master to get the correct level at the console. Now you set
the level for the tape recorder by reducing the buss master level, if necessary, to get
the digital recorder's track level at the "-6" level or the analog recorder's
track level at "0." |
| Using Pan Pots When Routing
Microphones |
| Sometimes you want to record several
microphones to two tracks to make a left and right image. An example of this is the Drums
where 5 microphones may be routed to two tracks labeled Drums Left and Drums
Right. |
| To let you do this there will be a small pan
pot control that is associated with the buss buttons. Usually, there will be a pan switch
that activates the pan pot used for routing. This routing panpot will pan between odd and
even busses that feed odd and even tracks. Odd busses and tracks are considered left,
while even busses and tracks are considered right. To use the pan pot you must send the
microphone signal to both an odd and an even buss. |
Keeping It Straight:
There are two sets of numbers that you need to be aware of in a
recording session. The first set of numbers is the microphone numbers. The second
set of numbers is the track numbers. Typically, there are more microphones than tracks.
Consequently, the track and microphone input numbers are different for the same
instrument. An example of a sixteen-track session is as follows:
Microphones:
1. Bass Guitar 2. Foot Drum
3. Snare Drum 4.
High Hat Cymbals 5. Smallest Mounted Tom
6. Middle (larger) Mounted Tom
7. Large Floor Tom 8.
Overhead Cymbals (Left) 9. Overhead Cymbals
(Right) 10. Electric Guitar #1
11. Electric Guitar #2 12.
Singer (Session Vocal)
Tracks:
1. Bass Guitar 2. Foot Drum
3. Snare Drum 4.
High Hat Cymbals 5. Toms & Cymbals Left
6. Toms & Cymbals Right 7.
Guitar #1 8. Guitar #2 9. Session Vocal
In this example, we can see that there are twelve microphone inputs and only nine
tracks. Monitor controls are for listening to the tracks in the control room. Cue controls
are for the musicians to hear tracks. Microphone and routing controls are to get
microphone signals to tracks.
On some consoles, the monitor and cue controls are separated from the microphone-input
controls. On the majority of the consoles, they are bunched together in strips. Although
the controls are together on one strip, different controls deal with different signals.
The monitor controls on strip #9 (in our example) will control how loud we hear the
session vocalist; microphone and routing controls on strip #9 will adjust the level of the
right overhead cymbal microphone.
WHEN MIXING MONITORS AND CUES, THE ENGINEER USES THE TRACK NUMBERS.
The Monitor & Cue Controls:
There will be a monitor level control for each track to adjust the level of the track
in the monitor mix. On larger consoles, this is often a small straight-line fader that is
just above the larger main fader. On smaller consoles, this is a rotary control some where
in the middle of the console strip. Increasing this monitor level control makes the track
louder in the monitor mix; reducing the control reduces volume of the track in the monitor
mix.
There will be a monitor pan pot control near the monitor fader. This pan pot will put
the instrument to the left side of the monitor mix when the control is counter-clockwise
and will put the instrument in the right side of the mix when it is turned clockwise.
Leaving the monitor pan pot in the center sends the track signal equally to both the right
and left sides of the mix, and the instrument will sound in the center between the
speakers.
There will be a stereo master control that is used to increase or decrease the overall
mix level. This control is usually a large fader in the center of the console. The level
of the mix will be seen on the main left and right meters of the console.
Once you have the mix for the tracks the way you want it, adjust the stereo master so the
meters peak around the "0" point.
Separate from the stereo master control will be a speaker level control to make the
speakers louder and softer. Adjust this control for a comfortable listening level.
Adjusting the speaker level control will not effect the way the meters read.
There will be a separate set of level controls, pans and master level control for the
cue mix. These controls are usually rotary and are above the monitor controls. Use the cue
level controls to make the tracks louder or softer in the musicians' headphones. The cue
pans will make the instruments sound left, right or center in the musicians' headphones.
The master cue control will increase or decrease the overall level in the musicians'
headphones.
Most consoles are normally set up to hear the main stereo mix. During the recording
session, this will be the monitor mix. On larger consoles, there is a set of monitor
selector switches. These allow other things to be heard over the monitor speakers (such as
a CD player or listening to the two-track recorder). The monitor selector will often allow
the Cue mix to be heard over the control room speakers. Often the engineer will want to
mix the cue signal on headphones, rather than on speakers. There is usually a headphone
jack on the console that allows this. |
| The Mixdown |
| The mixdown is similar for monitoring and for
final mixdown. On analog consoles you would change the channel inputs to "line"
to use the main input channels for the mixdown processes. On many digital
consoles you will have "tape return" channels that are used both for monitor and
for mixdown. |
The console channels need
to reach the main stereo outputs of the console. On many consoles, there will be a
"Stereo" button near the buss buttons (or in the middle of the console strip).
This button sends the channel signal to the stereo outputs. Some consoles have this button
labeled "Mix." Many of the larger consoles automatically route the channels to
the stereo output when the Mix Status button is pushed.
The signal is sent from the console to a
recorder that will record the final mixed tape. In today's control room, this is usually a
DAT recorder. "DAT" stands for Digital Audio Tape, which is a small digital
cassette used for 2 track, stereo recording.
|
Figure 4 - The
Mixdown |
During the recording session, the main channel controls
were used for controlling the microphone signal levels. During mixdown, these same
controls will be used to control the track signals that are routed to the stereo outputs. |
