processing

Radial Engineering Re-Amping Kit

Alan — Tue, 18 Nov 2008 11:03:33 +0000

I like it when something just works, but I always feel a bit ambivalent when I can't really notice it working.

The Kit

In this case, I've just been using the Radial Engineering Reamping Kit. It consists of two main components (the J48 active phantom DI and the X-Amp amp driver) plus a power supply for the X-amp and a plastic box to hold it all in.

Plugging In for Re-Amping

I read the instructions, mainly to figure out what happens with signal levels, plugged the Radial X-Amp in and in less than 5 minutes I was recording a guitar track again. It really was a case of plugging a mic XLR lead between the audio interface and the X-Amp, connecting up the power supply to the X-Amp and plugging a normal guitar lead between X-Amp and guitar. It's worth reading the manual for the order of connections and powering-up. I spent longer configuring the software mixer for my audio interface to output the guitar signal on a separate channel than I did connecting everything together.

Advantages

I can record the clean, DI signal no matter what the amplified sound is (ok, this is just using a DI box).
I can then re-record many times the clean through a number of guitar amps and/or cabinets with different eq and gain settings.
I find it goes a long way to reducing the lifelessness from direct recording into software amp emulation.
I can record a clean sound at unsociable hours, knowing that I'll be able to crank up the amp when it's more socially acceptable.
I can play with mic placement and room acoustics in a way that I can't when I'm the guitarist and recording engineer.
Allows me to record a heavier, overdriven version of the same track and blend this is with a clean recorded sound.

Disadvantages

You have to be disciplined or you can spend a lot of time tweaking the amp settings and re-recording the same track many times.
That's it, the components seem to work so well, I don't notice them working.

Overcoming Lifelessness

I mentioned the lifelessness of a guitar track recorded using software amp emulators. I believe they can produce great results, but for me as a guitarist, it doesn't feel the same as playing through a pure valve guitar amp and a 4x12 loaded with Celestion Vintage 30s (that just happens to be my longest-running preference). Some of my best guitar tracks have been recorded using software emulators, I only wish I'd been able to record them with at a mic'ed amp at the time.

I think it's down to the interaction between guitarist, guitar and amplifier/cabinet. Guitarists adjust their playing relative to what they hear coming out of the speakers, hence guitars recorded direct through software amp emulations can miss out the way that the guitarist changes their playing. Actually I think it's further than that, the guitarist changes their playing to suit the software emulator, after all, it's just another amplifier/cabinet combination to handle.

This kit goes a long way to helping me overcome the lifelessness of the software route, while still giving me the flexibility to record when I want to. It does not overcome it completely; you can't beat using the guitar, amp, speaker, effects and mic combination at the time of tracking that you want to hear on the finished song.

So in this case, the product's great and it does the job it's designed to do well. My ambivalence comes from the fact that it's such a simple job that, from that perspective, it has to do that it doesn't seem worth spending the money on. From the perspective of having something that works and does the job well, then you probably can't beat this re-amping kit.

Using Compressors to increase attack - Musical Creativity 45

Alan — Thu, 21 Aug 2008 15:30:37 +0000

Compressors are regularly used to tame errant dynamics or to increase the perceived volume of a track. As well as squashing the audio, the compressor can be used to bring out some elements more than others.

Letting the attack through

Remember when you were learning about compression? You probably wanted the attack at 0ms so that the whole signal was compressed equally. But it ended up in a squashed mess. The output sound had a different quality to what was put in. The guitar no longer sounded like a guitar, but like an old keyboard emulation of a keyboard. So we all gradually learned to allow the initial transients through with delays of 20ms upwards, depending on the instrument and the wanted effect. This allowed for a natural sound.

Reverse your thinking

Usually we're using a compressor to tame peaks or increase the perceived volume of the track by decreasing the dynamic range. This time we'll focus on increasing the dynamic range and still using a compressor.

Set the compressor to have a longer attack, e.g. 30ms to let the initial strike of a guitar string through. Set the compressor to moderately reduce the dynamic range of the rest of the signal. What you'll see if you compare the input to the output is that the initial peaks where the string is hit or plucked are louder in comparison to the rest of the signal.

Additional Options with Software

Pre-empting

The problem with hardware compressors is that they can only react once they receive the signal they receive. Software compressors have the advantage of being able to look-ahead at the signal and react before a hardware compressor could. That's useful for enabling the compressor to act on the initial transients.

Sidechain

You can also eq the input signal to trigger the side-chain. Some allow you to do this in the plug-in itself. For others you'll have to set up an aux/bus track and route the signal in parallel through that and eq the aux channel. This can be done in hardware as well if you eq the feed going into the sidechain.

Using Other Processors

Expanders

Expanders are built for job of increasing the dynamic range. Effectively, they're compressors with upward compression. And so should be more suited to increasing range. However, sometimes I prefer to use a basic compressor.

Enveloper

These react to the envelope of the sound. Think back to the basics of synthesis with every sound having Attack, Decay, Sustain and Release (ADSR). Envelopers provide a way to change the gain at the various stages. The one in Logic allows the user to change the gain at the Attack and the Release stages. So you could potentially just change the gain of the attack and leave the rest of the signal alone.

Gain

This doesn't increase dynamic range. I've included it because I had to increase the gain of the guitar track to match the results of the effects.

Results

I recorded a steel-string acoustic guitar using an x-y pattern of 2 small diaphragm microphones. These were routed to a bus (aux in Logic) and the effects were applied to the bus only. The main output for the microphone channels were removed, meaning that the signal was only going through the bus. I applied the following effects in turn: compressor, enveloper, expander and gain. For each one, I spent about 2 minutes changing the parameters on a part of the track that was of roughly average volume. Then I bounced the output to a separate audio file.

It's important to note that I only spent the time configuring the parameters for one part of the track. There were louder and quieter parts elsewhere in the track.

Rather than play the whole 5 minute track, I've extracted three parts; one quiet, one average, one loud.

The Screenshot

The screenshot shows the unprocessed as well as the results of having each of the compressor, gain, enveloper and expander applied in turn. The order from left to right is Average, Quiet and Loud.

Download a larger version of the image here

What you'll notice is that there's not that much different between most of them in the average and quiet. However, the compressor did a good job of using the dynamic range available. The gain effect just made everything louder, as it's meant to, but doesn't bring out the peaks. The expander and enveloper both coped well, but I prefer the compressor.

In the Loud section, we see the issues with applying parameters for one section only. In all reality, we'd probably be riding the faders or at least automating the fader/effect parameters. But for the moment, it gives us a good idea of how flexible the processors are. Most of them are showing clipped waveforms for the loud section, indicating too much make-up gain. The compressor waveform still has thin ends to the spikes indicating a more managed approach. And the sound does reflect that.

Quiet

Unprocessed

Gain

Expander

Compressor

Enveloper

Average

Unprocessed

Gain

Expander

Compressor

Enveloper

Loud

Unprocessed

Compressor

I've only published a few of these files in case anyone risks damaging their speakers. I haven't published the files with square ends, e.g. the "gain" and "expander" files.

Part of a series by Award Sounds offering a selection of creative ideas to kick-start or rejuvenate a composition.

Use of Tremolo - Musical Creativity 42

Alan — Thu, 26 Jun 2008 20:27:29 +0000

I've talked about tremolo as a musical feature before, this time I want to go into more detail.

First things first, let's sort out the guitarists: I don't mean using the tremolo arm/whammy bar or whatever you want to call it ("handle" as my girlfriend called it - and no she won't be picking up my guitars for a while). The whammy bar creates a vibrato feature, not a tremolo. Vibrato alters pitch.

Amplitude

Tremolo is the act of altering the volume of a note or set of notes. For an electric instrument, the simplest to hear is by regularly turning the volume knob up and down. The notes fade in, fade out, fade in, fade out and so on.

It's a great tool for livening up a piece of music. The previous article on the subject covered some more ways of using it.

Recordings

Tremolo features on a lot of famous recordings. Three extreme examples are:

How Soon Is Now - The Smiths

Crush with Eyeliner - REM

What's the Frequency Kenneth - REM

But it's used more subtlely on many, many more recordings. Think of any country song and listen to the guitar. Many of the 1950s and 1960s guitar recordings had tremolo on them. Think Duane Eddy (although he mixed it with vibrato by using the whammy bar a lot). Lots of Elvis recordings featuring Scotty Moore had tremolo. This situation was accentuated and facilitated by the inclusion of tremolo circuits in the guitar amps, e.g. Vox

Types of effect

The common tremolo effect alters the amplitude or volume of the incoming signal apply a regularly repeating pattern before output. The most common pattern is the sine wave, although some FX units also allow square and sawtooth. The output signal increases, decreases, increases, decreases, etc.

The waveform applied changes how fast the signal reaches the extremes and how long it stays there before beginning the journey to the other extreme.

Depth

If the signal is applied completely at 100% depth, then the output will have no signal at the points when the applied FX is at its lowest point, conversely it will have the maximum volume when the FX is at its highest point.

Lowering the depth introduces a less radical effect, to the point that if the depth were at 0%, then there would theoretically be no difference between the input and output. As with most effects, the most appropriate depth is usually somewhere between the two extremes.

Symmetry

The waveform applied so far has been the same on both sides, i.e. going up and coming down. Altering the phase allows more time for the signal to climb and a quicker fall or vice versa. This is great for imparting a slower or a rushed feeling to the track.

Phase

For a stereo tremolo, the default set-up is to have the signal applied equally, but alternately to each channel. Changing the phase control alters the timing displacement of the second channel compared to the first, which can be used to create panning echoes or dotted note rhythms.

No Depth?

I'd usually use a tremolo inline with the signal, either at the recording stage (e.g. between guitar and amp) or at the mixing stage (as an insert). If there's no depth control, then patch the tremolo into a send and emulate the depth by the relative values of the signal and send faders.

For guitarists, if there's no depth control, then you maybe able to use it in the amp's FX loop if you've got a variable dry/wet mix. This may not work well, since the FX would be placed after the pre-amp. Depends what equipment you're using.

Playing with fingers

A classical guitar tremolo technique involves repeatedly plucking the same string with the first, second and third fingers. This is often a bass and/or melody note plucked with the thumb followed by the three fingers or sometimes a fourth is employed but the fingering changes.

The most famous example is probably Recuerdos De La Alhambra by Francisco Tárrega, although I think Agustin Barrios Mangore's Una Limosna por el Amor de Dios (Alms for the Peace of God) shows the technique more.

Various forms of flamenco use a similar technique, sometimes using the thumb plus four finger notes (not necessarily four fingers, often three fingers with one repeated) to get a 5-tuplet pattern.

Pick

For electric guitar, rapidly repeated picking of the same note gives a tremolo effect that can be used in solos. Do it too often and you'll sound you can't move your fret-hand fingers. Best to intersperse it with other techniques. Check out the Ozzy Osbourne recordings with Randy Rhoads, e.g. Tribute, to get an idea of how to fit it into a solo. He doesn't use it that often, but when he does, it works well. Nowadays, watch Matt Bellamy of Muse. There are plenty of others, but they're not coming to mind right now.

In other forms of music, e.g. drag, it can be the main feature. This is more likely to happen on the lower strings of the guitar, with a springy/slap-back reverb. Think Dick Dale. Although perhaps not part of drag, Miserlou (as featured in Pulp Fiction) is a great example of how a simple riff can lead the track. The repeated picking comes from his experience with an oud (or ud).

Part of a series by Award Sounds offering a selection of creative ideas to kick-start or rejuvenate a composition.

Use random notes - Musical Creativity 38

Alan — Sun, 01 Jun 2008 15:28:37 +0000

Create a random part and modify it until it becomes musical. I'll describe a few options for taking a random parts and the processes I use for making them more musical.

1. Creating the randomness

I set Logic on a 4 bar cycle and hit keys at random on my keyboard. I chose a clean electric piano sound since they highlight any dissonance. It's not truly random because it's difficult to unlearn how to play, but after cycling through the 4 bars a few times it did become a mess of notes.

I could have used the humaniser function of Logic with the notes set at random (oddly, to de-humanise the part) . Didn't think of this until afterwards.

The glue part was because I was recording twice. I had to glue the parts together. There was no need to hae done this, it was just because of where I'd started and stopped recording and what I'd wanted to include.

2. Lengthen the notes

I changed the notes to half-time, doubling the length of each note. I expanded the region and the cycle region to account for this. So now I've 8 bars instead of 4.

3. Deduplicate overlapping repeating notes

If an event has a closely following event of the same pitch overlapping, this will turn them into two events, but the first will finish just before the second starts instead of overlapping.

4. Quantize

The placement of the events was a mess, they were all over the place with no real rhythm. I played with the grid, visually assessing which grid seemed to fit best. This was purely a quick estimation. I also changed the quantize value a few times and I settled on 24ths (triplet semi quavers). I also liked 12ths (triplet quavers) but it seemed to rigid, especially for having come from random notes.

5. Process length for overlapping notes

I did this, then decided to undo it. I liked both, but decided to keep the longer notes ringing. This option means that Logic will identify chords and ensure that the events are the same length. Without it, some notes in a chord may ring more than others.

6. Humanise Velocity.

I processed the midi, running it through the humanise function focussing solely on velocity. There wasn't a major change here, just slight enough to add some odd stress patterns. Maybe a groove template or similar would have been a better feature. Not sure.

7. Effects

These are in the order I added them (they're in a different order in the signal chain)

7a) It was crying out for a rotary cabinet emulator. Didn't need much, just something to take the edge of the louder, higher pitch notes.

7b) Guitar Amp emulator. I like using guitar amp emulators on non-guitar instruments. It's rare they need the full-on, high-gain distortion models, but mostly, just a clean or slightly overdriven blues amp can make a massive difference to a sound. For this one, I went with a clean amp.

7c) Overdrive - to have more control over the tone of the overdrive than provided with the guitar amp emulator, I went with a separate overdrive effect. Again most of the effect was dialled out to avoid losing the music in the distortion.

7d) Compressor - again to take the edge off and make the sound shine through more.

Some other ideas?

To be honest, add any effect and see what the result is. I tried a few that didn't work out in this case.

Delays can work well at creating rhythm out of random notes, especially if only on some of the notes
Use the random notes to trigger an arpeggio or other sequence (either directly into a virtual instrument or using the arpeggiator in the environment)
Pitch change processors - ideally you need a polyphonic processor. I tried running it through Logic's Pitch changer with variable results, not expecting much. Mainly I knocked out a few notes from the scale, but I wasn't happy with the sound
Use the midi filters to process some of the events but not all. For instance, you can select just the highest or lowest notes and split them out to a different channel and/or instrument. Then quanitise them differently to the rest of the events.
Most of the modulators will muddy the sound, reducing the sharpness of any dissonance from the original notes.
A tremolo will work similar to the modulators by reducing the sharpness of any dissonance but also provide a rhythm. Can be used on all notes or focussed on range.
Trigger the notes via another method, e.g. use a gate or a compressor with a sidechain to create a stuttering or pulsating effect. At least you can then bring the notes in line with the rest of the rhythm.

Gallery of Screenshots for each part of the process.

Want to do better?

I've attached the midi file so you can try for yourself. Let me know how you get on.

Part of a series by Award Sounds offering a selection of creative ideas to kick-start or rejuvenate a composition.

My Home-Grown Mastering Process

Alan — Thu, 06 Mar 2008 15:47:42 +0000

Introduction

When I master tracks myself, I do it within Logic Pro. I do not delude myself into thinking that the results of my efforts will be better than that of a professional mastering engineer. My view is that that there are times when mastering tracks yourself is the pragmatic choice. In this article, I provide details of my mastering process. This builds on the article about why process mapping is relevant to music and audio.

Process Map

Click the process icon to see the larger, more detailed process map.

The Individual Tracks

After mixing and applying eq for the track itself, I check the stereo-image (especially mono-compatibility), then export the track without dynamic compression at 96Khz/24bit and type 1 dithering, just to handle dithering from Logic's internal bit-depth down to 24bits. There's a lot of debate about whether dithering at this stage is necessary. I'd usually say that if I can't hear the difference, then I don't do make the change, but for some reason, dithering at this stage is one step that I do perform. By exporting at that stage, I receive the clearest version of the source file that I can have.

Putting the Tracks Together

I then import the track into another, empty, Logic Pro Song that I use just for mastering CDs. This is where I'll look at the mix of tracks and applying effects across the CD. I'll apply any eq to even out the tone across the whole CD, automate the fade-in-out levels and pass the mix through a compressor if appropriate.

Once I'm happy with the mastered sound, I export that to the destination format. Assuming it's a CD, then 44.1kHz/16-bit with type 3 dithering (or noise shaping). At the same time, I'll export an mp3, complete with mp3 ID tags.

Burning the CD

I load the CD tracks into Waveburner and burn the CD from there. This involves setting the gap between tracks to 0 seconds since the fade-ins and fade-outs have already been rendered as part of the "mastered" mix from Logic in the previous steps.

Convoluted?

I think my process is too convoluted. I would use Waveburner earlier in the process instead of loading the tracks into the empty Logic Pro track. I did try that route but I was never comfortable with its stability. It just crashed at odd times and I'd have to start again. I found the safest way was to use Logic Pro a second time for arranging all of the tracks together.

Caveat

I'm not advocating that we all should master our own tracks. Mastering engineers have a role to play for finishing your CD or other production.

Why am I publishing this?

I've never seen the process described well enough that it makes any sense. I understand the principles well-enough, I've no problem with that side of things. It's putting those principles into use using the software applications at hand that causes the issues. I've seen snippets of information but they never fully answer when you should dither or not and how, when to compress, etc. I want to encourage debate about the processes we use and I'm volunteering some of mine to get the ball rolling.

Ideally I'd like some of the processes to start tackling the main questions I see on recording forums. Hometracked.com has a list of 7 popular questions which align very closely with what I see as well.

Talk

The process diagram is a bit simplistic, but it should be enough to get the debate started. I can add in the extra detail as conversations progress. Want to share your own processes, let me know.

For more background on process mapping, I've started an online book on the Fundamentals of Process Mapping.

Process Diagram License

This work is licensed under a
Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Lock the Bass in - Musical Creativity 28

Alan — Sun, 10 Feb 2008 13:53:46 +0000

Following on from the article about using gates on drums. I want to describe the main reason I use gates and that's to lock the bass into another pattern such as the kick drum.

It's quite a common use for a gate and when set well, it's subtle and almost unnoticeable, but definitely noticeable when you turn the effect off. It's simple to set up although it does involve a few steps.

The Set-up

Let's say we start with two tracks:

Channel 1 is the drums. Most likely a stereo set from a loop/drum plug-in or a submix from acoustic drums
Channel 2 is the bass guitar. Most likely mono (although a blended mix of mics/DI etc could also be used

The channel order's completely up to you. The only reason I've mentioned track numbers here is so that it's easier to refer to them as I type.

The 1st Gate

We'll put a send on Channel 1 (drums). In Logic, let's say that we send the signal to Bus 1. I usually set it 0dB (that's n oreduction or gain on the send in Logic) most of the time and pre-fader unless I need to process the drums a lot.

Now we go to the send channel (Bus 1). If you've got the drums playing, you should see the meters for the Bus channel moving in sync with the drums. We only want the bass to be in sync with the kick drum, not the whole drum kit.

We now insert the gate on the send channel Bus 1. Set the gate so that it only triggers on the kick drum. If there's a monitor function so you can hear what the gate responds to, then use that. When you've got the setting, stop the send going to the main output or mixbuss. We don't need the sound as an output into the main mix. You should see Bus 1 channel's meters respond to the kick drum only now.

The 2nd Gate

Now go to the bass channel (Channel 1) and insert a noise gate there. You want it to trigger when there's a bass signal so set the threshold accordingly. I usually have the signal reduction set to only -2dB or -3dB. The reason for that such a small dB reduction is that the gate will always let the bass signal through, but will also let the extra 2dB through when the kick drum triggers it. To do that we put Bus 1 as the gate's sidechain.

The Result

Listen to it now and the bass should be accentuated with the kick, giving the impression of being locked-in more that it was previously.

Quick settings in Logic

Setup the gates as above and select the Isolate Kick preset in the gate. Listen to the signal with the monitor function. Actually you can do without this and use the meters instead if you can hear the kick well enough. Change the eq filter and threshold so that only the kickdrum comes through - usually this means reducing the High Cut almost to its lowest level so that it doesn't pick up the snare and bringing down the threshold until the kick triggers the gate. Turn off the monitor in the gate and change the output of the aux channel so that it has no output.

For the gate on the bass, select the Isolate Bass preset. Change the sidechain input to Bus 1. Set the threshold so that the bass always comes through and set the reduction to -2dB.

Why 2 gates?

I find it to be a lot more accurate. It's possible to route the Channel 1 (drums) to the sidechain input of the gate on Channel 2 (bass). You can then change the eq setting so that only the kick drum comes through. But I've always found that there's a little bit of leakage from other instruments doing it this way and rather than just have eq filtering out the drums, I like having the 1st noise gate isolating thekick. At least that way, I can decide whether I'd prefer to miss a few hits of the kick or have it respond to a few hits from the snare as well, depending on how tight the threshold and eq values are.

Other ideas

Vary the reduction amount to get a more dramatic accent until it quickly starts to have a detrimental effect rather than being a positive creative tool. But as always, try it, it may prove useful to you.

You could also switch the gate for a compressor (and again use the Bus 1 as the sidechain input) for the opposite effect. It might sound like it wouldn't work since it would decrease the bond between the kick and bass. I find it useful when the kick has a tone of its own that I'd like to come through. In that case, the bass and the kick together may be too much so using the compressor allows the kick to shine through.

I think you can do something similar by using a positive value in the reduction. This is where the terminology gets confusing: to increase the non-triggered volume, have a positive number for the reduction (i.e. it's not a reduction anymore). To think around this, interpret the reduction value as what the gate does to the non-triggered signal.

Part of a series by Award Sounds offering a selection of creative ideas to kick-start or rejuvenate a composition.