emulation

Emulating Drums - Musical Creativity 24

Alan — Thu, 31 Jan 2008 13:27:34 +0000

Following on from the previous article on emulating bass, this article is about emulating drums and mainly about emulating drummers.

I'm of two minds when I emulate drums. I'm either:

aiming for a realistic drum sound or
aiming for a drum sound that doesn't need to sound like a real drum

The first aim involves working with compromises. Ideally, I'd be better off recording a good drummer playing an acoustic kit in a nice-sounding room with great mics, preamps, etc. That's not always possible. And the aim maybe to have something ready very quickly, so I turn to emulating a drummer.

The second aim is more useful for generating percussive elements that fit tonally into the music but with a different impact to that which I could achieve with a normal drum-kit. I'll discuss those in a separate article.
In this article, I'll stick with (1) achieving a realistic drum sound.

Loops

My short piece of advice is to use drum loops. Use some decent quality loops with sufficient rhythm variation and inherent tonal consistency and many would be hard pressed to tell the difference between a drummer and a loop. If they can tell the difference, it's either a bad set of loops or user error, e.g. you've used the same loop too often in the song. After, how could they tell the difference since it would have been a real drummer who recorded the loop in the first place.

Midi

The long answer is for when you don't have any suitable loops, including if you don't have any loops. Then you'll probably be resorting to midi to trigger drum sounds in a sampler. There are some tricks to make it sound more realistic.

Play like a drummer

Drummers have a maximum of four limbs. That's an immediate restriction of 4 items being hit at any one time. Can be more than 4 note polyphony though due to layering and the release of certain instruments (e.g. cymbals). Actually the right hand can hit the rim and the head of the snare together, but that's a bit of an exception.
That's the first restriction. If you want it to sound like a drummer, then limit it to four hits at a time.

Layout

Also look at the layout of a traditional drumkit. For a right-handed drummer, the right-hand usually crosses the body and plays the hi-hat, while the left-hand plays the snare. Either hand is used for the toms and cymbals. And either hand can add to the other hand to double up on the snare or hi-hat. Different styles call for different arrangements. That's the traditional pop/rock layout and handling.

Watch the combinations

The short closed hi-hat sound is formed by the right-hand hitting the hihat while the left-foot holds the hi-hat closed. If the right-hand is hitting the snare, toms or cymbals, you can't get a closed hihat sound. If would be the gated half-open sound caused by the left foot lifting the top hi-hat and then pulling it down. It's a weaker sound than closed hi-hat. A rock drummer may have a much more ringing open hit-hat sound, especially for keeping up with doubletime kick and snare patterns.

Would a drummer alternate?

If the pattern relies on 16th beats on the hi-hat, then the drummer would most likely alternate hits between the right and the left hand. I know of four ways to implement this:

Look at each hihat hit and manually change alternate hits to use a different hi-hat sound
For using a sampler such as Kontakt 2 or Kontakt 3, you can write a script to alternate between the left and right sounds of the hi-hat with each hit. You could get even more serious and tie it into the snare hits (assuming that a snare hit would be left-hand and hi-hat would be left-hand). The more you think about it, the more you can write.
Use logical processing on the midi file so that it separates out alternate notes. Rather than processing every alternate note, it may be easier to divide your bar into two sets, those corresponding to the beat and those on the off-beat. Then alter the two sets separately.
Use a drum-specific software plug-in that will calculate which sound should be played. This is what the brain unit of most electronic drums should be doing, interpreting the received notes so that they sound more realistic.

It also applies for other drums as well, not just the hi-hat.

The Machine Gun

The bane of a lot of 1980s pop was the electronic snare that sounded the same no matter how hard you hit it. Hit it in a quick repetition and it sounded like a machine gun. There was just no flexibility. Drum synthesizers and samplers have come on a long way since then, but unfortunately some interfaces do not make it obvious to avoid. It's not specific to snares either; hi-hats, toms, anything hit rapidly and repeatedly risks introducing this effect.

Similar to the methods for alternating the hands, I can think of 4 ways of implementing this:

Look at each hihat hit and manually vary the velocity of nearby hits. If there are left and right sounds for the drum, then alternate them as a drummer would. Also vary the timing slightly, too regular and it may sound artificial.
For using a sampler such as Kontakt 2 or Kontakt 3, you can write a script to alternate between the left and right sounds of the hi-hat with each hit. You could get even more serious and tie it into the snare hits (assuming that a snare hit would be left-hand and hi-hat would be left-hand). The more you think about it, the more you can write.
Use logical processing on the midi file so that it separates out alternate notes. Not sure how effective this is for avoiding the machine gun effect. Largely depends on your the processing options offered by your DAW. Again, similar to the approach for alternates above, it may be worth dividing your bar into two sets, those corresponding to the beat and those on the off-beat. Then process the two sets separately.
Use drum-specific software plug-in that calculates the appropriate velocity or sample layer. This is what the brain unit of most electronic drums should be doing, interpreting the received notes so that they sound more realistic.

Ghost Notes

What makes a real drummer more interesting than a basic drum pattern is the presence of ghost notes. This is where the drummer would lightly hit a drum, e.g. the snare, but not as a focus of the rhythm. Often these pre-empt the main snare hit, almost leading into it. The ghost note would be short and lower in volume than the main hits. The ghost notes don't just have to pre-empt the main hits, a drummer will include them in to vary up the patterns and to add spice to the rhythm. If they're occurring in the same place in every beat, then they're probably not ghost notes but an integral part of the pattern. I've always seen ghost notes as being variable throughout a song. Due to the varying lower volume, if you're not listening carefully, some ghost notes would end up being imperceptible.

Try listening to a jazz drummer, especially if they're playing a simple blues rhythm. You'll notice the ghost notes more when the rhythm is simpler.

Accuracy

This is one I have issues with. How accurate does a human drummer need to be? If you look at recordings of a good real drummer, there's a lot of variation in how accurately they hit compared to the beat. But it will still sound in time. The issue I have is that it's against my understanding that being inaccurate is the right thing to do, just feels wrong to admit that, but it seems that being slightly inaccurate is the way to play. Goes to show that none of us are perfect. I tend to keep the main beat very close if not exact and vary other hits. And I always think about using groove features or humaniser functions.

In the Mix

The drums coming out of most samplers are still a raw instrument sound. There may be some reverb and compression but do they suit the music you're writing? If not, remove them and add the processing you want to add. More so, you may want to change the sound of a single drum, e.g. wanting to compress the kick drum more and add more of the click from the beater with eq. If so, then it's best to separate out the drums into separate outputs. You can then modify the sound of the individual drums to suit your tastes.

While you're at it, decide how you want the drums to sound in stereo. Are they all central? Or should it be set out from the drummer's or the audience's perspective. Then group them back together for drums for ease and so you have the option of processing the drums as a whole.

Other techniques

Harmony Central has some great suggestions for more advanced techniques. The concept of mute groups looks especially useful.

Reference CD

What should drums sound like? If you're aiming for realistic drums, then you'd do well to start with some reference files

There is some interesting information about the Led Zep sound over at Guitar Player

Learn to drum (even if only in theory)

Have a look round for lessons on the rudiments of drumming. Being armed with this information will help you create more realistic drum loops. I learnt by sitting in front of a kit twice a week and getting a few pieces of advice every month. No proper lessons. Even so this basic introduction helped me understand no end what it means to create a drum track. Understanding what constitutes a basic beat is the starting point. Try starting with these:

Shavano has an old but still useful article for anyone wanting to program drum midi patterns

Drum Plug-ins

I mentioned drum plug-ins above. I don't use the more advanced plug-ins so I can't really comment beyond that I've heard some very positive reviews including from some good drummers. From the demo samples I've heard, they introduce a level of realism that is difficult to achieve on your own with midi programming. There's a range of drum plugins offering different functionality.

The simplest are just sample triggers where you select the samples to be played and place them on a midi track. This is the basic type that you'll find with a lot of DAWs. If you're lucky, you can select from different drum sets, create your own, change the relative volume and/or pitch levels or even modify the envelope of the individual drums.

More advanced plug-ins allow you to select more authentic-sounding drumsets, designed to sound like specific Pearl or Ludwig sets and so on. They'll also give you the option of room sounds, microphone types and microphone placement. Extra features include the ability to blend the mic mixes. As they get more advanced, the plug-ins interpret the midi input into something more like what a drummer would play. This is the type that interest me more than others.

Some include drum patterns in a variety of styles, giving you the ability to compose the song's rhythm very quickly. They may even include intro and fill patterns. Remember the basic sampled drumkit on the old casio homekeyboards of the 80s? Well, this feature's a more advanced and flexible version of that. It's ok for using when keeping a beat, especially as a more interesting clicktrack, but I wouldn't use them in the end product.

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

Emulating Guitar - Musical Creativity 20

Alan — Thu, 17 Jan 2008 16:42:42 +0000

Which type?

Firstly, I'd want to decide which type of guitar to emulate and then understand as much as I can about that instrument particular type of instrument and how it's played. Actually, that can be said of emulating any instrument. Take note of the instrument's range and where its tonality changes with pitch or volume. For an electric guitar, take note of the pickup types, whether it's strummed or picked, how many notes at a time, how the guitar would be recorded, etc. A strat sounds markedly different to a Les Paul.

Apply the process

Whatever you use to produce the sounds for an electric guitar, it generally sounds better being put through a guitar amp simulator as well, in much the same way that you may do with a guitar. Guitar amps are often mic'd up with two mics and the two tracks mixed together for the desired effect. So try the same sound through two channels, one to emulate the close-up dynamic microphone and another to emulate a condenser placed further away. The condenser channel would be subject to more room sound, so bring in your convolution effects if necessary.

It's the space as well

The recording space and techniques used to record a classical nylon guitar would be different than the for a electric guitar through a hi-gain amp. They would also be mixed differently.

I'm a guitarist, why would I want to emulate a guitar?

I can think of several reasons:

1) Saves having to get a guitar, amp, microphones, etc out to check out an idea

This isn't really an issue for me, I have an acoustic and at least one electric ready to go at all times. But if you're short on available space in your home studio, I can see this being the case. Occasionally I'll change the patch on a channel to a guitar so some midi notes I've written are produced by a guitar-ish sound, just to get a quick feel for whether it's worth learning the part on a guitar. If I then want the guitar recording, I'll record it properly myself.

2) For creativity

For the same reasons in starting on a different instrument, to be able to play in a different style to what you're used to playing on guitar. By trying to play the instrument on a different interface (e.g. a midi-equipped or USB keyboard), then you have to think differently. That brings out a different result compared to just playing guitar on its own.

3) For flexibility

To play something you couldn't normally play on guitar. If sweep arpeggios are beyond your talent, then you could program them in using midi. Or if it's genuinely impossible to play on a guitar, e.g. a stab consisting of 4 consecutive semitones, e.g. D, D#, E and F in the same octave. Ok, that example would be pretty discordant, but it may float your boat for one reason or another. More useful would be chord inversions that may be theoretically feasible but so awkward to transfer between that they're impossible from a practical perspective.

How effective can it be?

I've found it inspiring to try different musical phrases using an emulated guitar. I've also found it helps with my composing workflow. Furthermore, I can produce something technically complex in a shorter time than it would take to learn it. This has been useful when I've wanted to record an idea for future reference. Better to have the emulated sound that fits into rough mix, which will give me longer to learn the more complex parts, than forget what I wanted to record. In that sense, I'd be using it for taking notes.

If sonic accuracy is your aim, then perhaps try one of the more specialist virtual instruments such as RealStrat. I don't use virtual instruments, I remember looking into one a couple of years ago and I was impressed, very impressed in fact by the resulting sound demo. I was suspicious of how much time it took to get that result. At some point I'll go back and try it again and look in more detail.

Tuning

Apart from the fact that the strings can be tuned to different notes, e.g. nu-Metal would often feature at least a dropped D, if not yet another whole tone decrease, the interaction of the strings themselves can be important. For any guitar with a floating bridge (think most stratocasters and telecasters), the pitch of any one string is dependent on what's being fretted on the other strings. Bend one string and the others will decrease in pitch by a few cents. A lot of blues leads and chicken pickin' styles make use of this effect.

Tone

Guitarists apply tone and produce different sounds just in their playing style. For instance:

1) picking nearer the bridge produces a harsher tone (ponte)

2) picking nearer the neck produces a softer tone (dolce)

You could emulate the above by have a simpler tone more like a sine wave for the dolce sounds and adding more harmonics and a bit of distortion to emulate ponte. I'd also bring in compressors and gates to modify the envelop so that the attack on dolce is slower. The overall volume is lower on dolce than on ponte. If you're going to emulate a classical guitar, then ensure that your samples/virtual instrument can handle the difference between ponte and dolce and hopefully a few points in between.

Free or Palm-muted

By resting the side of the palm on the strings near the bridge, the guitarist can dampen the sound of the strings. This is reminiscent of a low-pass filter and if the guitarist increases the pressure applied to the strings, the cut-off frequency is reduced, thereby reducing the resulting tonal range. The palm-muting also reduces the dynamic range, probably why it's used to much in heavy rock chugging. By keeping the volume consistent, you can quickly develop a rhythm. Actually guitarists take it a step further and change the pressure applied as the notes are played. This can result in notes being accented or muted througout the phrase, accentuating the desired rhythm.

Further info

KVR Forum had a good thread on emulating guitars.

How a guitar works

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