AF’s Weblog

July 15, 2011

Vocals Processing Tips: Part 2

Hard disk recording techniques have affected every aspect of recording, including vocals. Although overdubbing vocals has been a common technique for years, today’s programs let you do multiple tracks of vocals, and make a “composite” with all the best bits. We’ll cover how to do that, then talk a bit about compression and reverb.

Composite Vocal Tracks

Cutting and pasting has benefited vocals, as you can do multiple takes, and splice the best parts together to make the perfect “composite” vocal. Some producers feel that stitching together vocals doesn’t produce as natural a “feel” as a take that goes all the way through from beginning to end, while others believe that being able to choose from multiple takes allows creating a vocal with more range than might occur with a single take. If you want to try composite vocals, here are the basic steps.

Record the Takes

Record enough takes so there’s plenty of material to piece together a good performance (loop recording is particularly handy for doing vocals). While you’re in a recording mood, record a little bit of the track without any input signal. This can be handy to have around, for reasons described later.

Audition the Takes

Audition each take, and isolate the good parts (by cutting out unwanted sections). I recommend setting loop points around very short phrases.

Solo each take, one after the other. If you’re not going to use a take, cut the phrase. If a take is a candidate for the final mix, keep it.

Pick the top 3 or 4 candidates, and remove the equivalent sections from the rest of the tracks. Now repeat this procedure, phrase by phrase, until you’ve gone over the entire performance and found the best bits

Ligne de chant compilée

In Sonar, several takes of vocals have been recorded. A mute tool has muted portions of each track (the waveforms are shown as shaded), with the remaining parts making up the final vocal.

Next, listen to combinations of the various different phrases. Balance technical and artistic considerations; choose parts that flow well together as well as sound technically correct. Sometimes you might deliberately choose a less expressive rendition of a line if it comes just before an emotional high point, thus heightening the contrast.

Once you have the segments needed for a cohesive performance, erase the unused parts. If you want to archive everything “just in case,” go for it. But if after putting the part together you think it could be better, you might be better off re-cutting it than putting more hours into editing.

Ligne de chant compiléeSeveral takes of vocals were recorded into Cubase SX, and edited to create one final vocal. The program shows the elements that make up the final vocal by highlighting them in green.

Bounce the Takes

This isn’t absolutely necessary, but converting all the bits into a single track simplifies subsequent editing and processing.

Before bouncing, play the tune through from start to finish and match the segment levels as closely as possible. Also check the meters for any send bus or master bus the tracks are feeding, and adjust levels (if needed) so there’s no distortion. Generally, the bounced track will be derived from a bus or master; if there’s distortion, the bounced track will have distortion too.

This is also where the recorded noise might come in handy. Sometimes I’ve had to do a quick fade on the end of one segment, and a fade in on the beginning of another, leaving a dead silent gap between phrases. Layering in a bit of the noise signal gives better continuity, and keeps the part from sounding too “assembled.”

After everything’s set, implement the program’s bounce or mix to hard disk function. You can typically bounce to an empty track, or “render” the audio to disk and bring it back into the project.

Edit the Composite Track

At this point, I bring the composite track into a digital audio editor for clean-up. Here are some typical processes:

  • Phrase-by-phrase gain adjustments. If a phrase has mismatched levels, use the program’s level change DSP or mix automation to fix the problem.
  • Fix breath noises and inhales. There might be “flammed” inhales from combining two different takes, so cut one. However, don’t eliminate all inhales and breath noises — they keep things “human.”
  • Add overall dynamics control, reverb, EQ, echo, etc. if needed. Do not add these while cutting individual takes; it will be much harder to match the effect, and in the case of reverb, tails might get cut off. Adding processing after optimizing the entire track will give the best results.

Tidy Up Your Hard Disk


After the vocals are done, check how your program deals with deleting unused segments, as this can reclaim significant space from your hard drive.

Now let’s take a look at compression…

Reverb Tips for Vocals

Nothing “gift wraps” a vocal better than some tasty reverb. My favorite reverb for voice is a natural acoustic space, but as reverb rooms are an endangered species, you’ll likely use a digital reverb. Reverb settings are a matter of taste, but two parameters are particularly important.

Waves RVerb (Renaissance Reverb)

A reverb’s Predelay and Diffusion parameters are crucial to getting good vocal sounds. This reverb, the RVerb plug-in from WAVES, offers an exceptional amount of control.

Diffusion: With vocals, I prefer low diffusion, where each reflection is more “separated.” Low diffusion settings often sound terrible with percussion, as the individual echoes can have an effect like marbles bouncing on a steel plate. But with vocals, the sparser amount of reflections prevent the voice from being overwhelmed by too “lush” a reverb sound.

Predelay: This works well in the 50-100 ms range. The delay allows the first part of the vocal to punch through without reverb, while the more sustained parts get the full benefit of the reverberated sound.

To read the full article see: Vocals Processing Tips Part 2

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March 4, 2011

Noise Gates Don’t Have to be Boring

Noise gates aren’t as relevant as they were back in the analog days, when hiss was an uninvited intruder on anything you recorded. But noise gates can do some really cool special effects that have nothing to do with reducing hiss. This article shows how to make them a lot more interesting, and throws in a bunch of fun audio examples, too. But first, let’s do some noise gate basics for the uninitiated.

Noise Gates Basics

A noise gate mutes its output with low-level input signals, but higher-level signals can pass through. Following are the typical adjustable parameters found in a noise gate, whether analog, digital, or plug-in.

  • Threshold: If the input level to the gate passes below the threshold, the gate “closes” and mutes the output. Once the signal exceeds the threshold, the gate opens again.
  • Attack: This determines how long it takes for the gate to go from full off to full on once the input exceeds the threshold.
  • Decay: This sets the time required for the gate to go from full on to full off once the signal falls below the threshold. Since decaying signals often criss-cross the threshold as they decay, increasing the decay time prevents “chattering.”
  • Key input: Normally, the gate opens and closes based on the input signal’s amplitude. The key input allows patching in a different control signal for the gating action (for example, using a kick drum as the key signal to turn a sound on and off in time with the kick’s rhythm). Note that in most cases, you won’t find this in plug-ins, only in hardware units.

All right, let’s get into applications.

Selective Reverb

I was using a premixed drum loop from the Discrete Drums Series 2 library, but in one particular part of the song, I wished that the snare—and only the snare—had some reverb. Although Series 2 is a multitrack library, I didn’t want to go back and build up the drum loop from scratch. So why not just extract the snare drum sound, put some reverb on that, and mix it in with the drums?

Referring to Fig. 1, I copied the drum loop in Track 1 to a second track in my sequencer (if you were doing this in hardware, you’d split it into two mixer channel inputs). In the second track, there’s EQ inserted to roll off all the low end, which took most of the kick out of the signal, as well as the high end, to reduce the level of cymbal crashes.

Reverb sélective

Fig.1

The next step was to insert a noise gate in Track 2, and raise the gate threshold so that only the snare peaks made it through (the screen shot shows a Compressor/Gate plug-in, but the compressor was disabled by setting the ratio to 1:1). These peaks fed the reverb, which dumped into the master bus along with the original drums. The end result: Reverb on the snare only, added in with the rest of the drums.

Now let’s take a closer look and listen to some samples…

Kick Drum “Hum Drum”

Here’s a trick for hardware noise gates. Suppose you want to augment an existing kick drum sound with a monster rap kick, like that famous TR-808 rap sound. Here’s a sneaky way to do it:

  1. Set a sine wave test tone oscillator somewhere between 40 and 60Hz, and plug it into a mixer channel module containing the noise gate.
  2. Patch the kick drum into the gate’s key input and set the threshold relatively high, so that the kick exceeds the threshold for only a very short amount of time.
  3. Set the noise gate decay for the desired amount of oscillator decay. Hopefully your gate decay can go up to about 2 seconds, but even 1 second can do the job.

Now whenever the kick drum hits, it opens up the gate for a fraction of a second and lets through the sine wave; the decay time then provides the desired fadeout.

Real Time Manipulation

This real-time performance tip can sound very cool with hip-hop, techno, and other types of music that rely on variations within drum loops. With most loops, the snare and kick will reach the highest levels, with (typically) hi-hat below that and percussion (maracas, shakers, tambourine, etc.) mixed in the background. Tweaking the noise gate threshold in real time causes selected parts of the loop to drop out. For example, with the threshold at minimum, you hear the entire loop. Move the threshold up, and the percussion disappears. Move it up further, and the high-hat drops out. Raise it even higher, and the snare and kick lose their decays and become ultra-percussive.

To read the full detailed article with sound samples see: Noise Gates

 

September 30, 2009

Understanding Reverb

When we hear sounds in the “real world,” they are in an acoustic space. For example, suppose you are playing acoustic guitar in your living room. You hear not only the guitar’s sound, but because the guitar generates sound waves, they bounce off walls, the ceiling, and the floor. Some of these sound waves return to your ears, which due to their travel through the air, will be somewhat delayed compared to the direct sound of the guitar.

This resulting sound from all these reflections is extremely complex and called reverberation. As the sound waves bounce off objects, they lose energy and their level and tone changes. If a sound wave hits a pillow or curtain, it will be absorbed more than if it hits a hard surface. High frequencies tend to be absorbed more easily than lower frequencies, so the longer a sound wave travels around, the “duller” its sound. This is called damping. As another example, a concert hall filled with people will sound different than if the hall is empty, because the people (and their clothing) will absorb sound.

Reverberation is important because it gives a sense of space. For live recordings, there are often two or more mics set up to pick up the room sound, which can be mixed in with the instrument sounds. In recording studios, some have “live” rooms that allow lots of reflections, while others have “dead” rooms which have been acoustically treated to reduce reflections to a minimum – or “live/dead” rooms which may have sound absorbing materials at one end, and hard surfaces at the other. Drummers often prefer to record in large, live rooms so there are lots of natural reflections; vocalists frequently record in dead rooms, like vocal booths, then add artificial reverb during mixdown to create a sense of acoustic space.

Whether generated naturally or artificially, reverb has become an essential part of today’s recordings. This article covers artificial reverb – what it offers, and how it works. A companion article covers tips and tricks on how to make the best use of reverb.

Now let’s take a sneak peak into the nitty gritty of reverb…

….

Advanced Parameters II

High and low frequency attenuation. These parameters restrict the frequencies going into the reverb. If your reverb sounds metallic, try reducing the highs starting at 4 – 8kHz. Note that many of the great-sounding plate reverbs didn’t have much response above 5 kHz, so don’t worry if your reverb doesn’t provide a high frequency brilliance – it’s not crucial.

Reducing low frequencies going into reverb reduces muddiness; try attenuating from 100 – 200Hz on down.

Early reflections diffusion (sometimes just called diffusion). Increasing diffusion pushes the early reflections closer together, which thickens the sound. Reducing diffusion produces a sound that tends more toward individual echoes than a wash of sound. For vocals or sustained keyboard sounds (organ, synth), reduced diffusion can give a beautiful reverberant effect that doesn’t overpower the source sound. On the other hand, percussive instruments like drums work better with more diffusion, so there’s a smooth, even decay instead of what can sound like marbles bouncing on a steel plate (at least with inexpensive reverbs). You’ll hear the difference in the following two audio examples.

Maximum DiffusionNo Diffusion

The reverb tail itself may have a separate diffusion control (the same general guidelines apply about setting this), or both diffusion parameters may be combined into a single control.

Early reflections predelay. It takes a few milliseconds before sounds hit the room surfaces and start to produce reflections. This parameter, usually variable from 0 to around 100ms, simulates this effect. Increase the parameter’s duration to give the feeling of a bigger space; for example, if you’ve dialed in a large room size, you’ll probably want to add a reasonable amount of pre-delay as well.

Reverb density. Lower densities give more space between the reverb’s first reflection and subsequent reflections. Higher densities place these closer together. Generally, I prefer higher densities on percussive content, and lower densities for vocals and sustained sounds.

Early reflections level. This sets the early reflections level compared to the overall reverb decay; balance them so that the early reflections are neither obvious, discrete echoes, nor masked by the decay. Lowering the early reflections level also places the listener further back in the hall, and more toward the middle.

High frequency decay and low frequency decay. Some reverbs have separate decay times for high and low frequencies. These frequencies may be fixed, or there may be an additional crossover parameter that sets the dividing line between low and high frequencies.

These controls have a huge effect on the overall reverb character. Increasing the low frequency decay creates a bigger, more “massive” sound. Increasing high frequency decay gives a more “ethereal” type of effect. With few exceptions this is not the way sound works in nature, but it can sound very good on vocals as it adds more reverb to sibilants and fricatives, while minimizing reverb on plosives and lower vocal ranges. This avoids a “muddy” reverberation effect that doesn’t compete with the vocals.

THE NEXT STEP: APPLYING REVERB

Now that we know how reverb works, we can think about how to apply it to our music – but that requires its own article! So, see the article “Applying Reverb” for more information.

To read the full detailed article see:  Understanding Reverb

August 27, 2008

QuikQuak RaySpace 2 review

Filed under: Computer music reviews — Tags: , , , — audiofanzine @ 1:17 pm

There’s such a plethora of software reverbs, that an editor who wants to be a cut above the rest has to rely on originality. By allowing you to create any reverberating space you’d like, and to precisely define a vast amount of its sonic characteristics, for a reasonable price, QuikQuak RaySpace is a reverb that has a lot going for it.

QuikQuak RaySpace 2 - AudioFanzine

An original concept, numerous possibilities, complete automation allowing you to move your Listener or sources within a space/room, very efficient ergonomics, low CPU consumption and an interesting sound: RaySpace offers way more than its price might suggest. But you have to be aware that, despite the 90-plus factory presets (classified by type, very good programming), the plug-in needs a certain learning curve when you want to start from scratch. It is not as simple as choosing an algorithm, and setting the pre-delay,

reverb time and EQ… You have to tweak and refine each parameter, sometimes randomly, and the whole process is very different from the usual way of working with reverbs. For example, the EQ isn’t there only for small adjustments; it is essential for creating the final sound. And the interaction between the various parameters also implies a certain amount of practice. Luckily, the ergonomics are really well designed, and the various displays will be of great help.

In a nutshell, RaySpace is a nice surprise, and anybody can verify this by simply downloading the demo version from Quikquak’s site.

Concept
Customized space creation
Visual approach
3D visualization
Automation
Ability to move objects around within the spaces (Listener and/or sources)
Lots of parameters
Creative potential
Surround
Fast Impulse export
Undo and Recall
Low CPU consumption
Price

Needs a learning curve
Loss of bearings – very different from most reverbs
Can’t handle all scenarios
High frequencies sometimes a bit harsh
No zoom in Edit mode
Only one automatic box shape (parallelepiped)
Only one global height
Only one definition of wall material

Check out the complete QuikQuak RaySpace 2 review.

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