Recording tools: The Microphone

As with any other process, the tools used are all important, but if I had to decide which tool was the most important (a futile act, seeing as all the components need eachother to function) it would have to be the microphone.

Microphones are the physical "ears" of the recording session. Their purpose is to transate the physical sound waves from the air, into an electrical signal that can then be recorded. Sound is actually the movement of air molecules, or rather the movement of regions of denser and less dense particles. When a 1kHz tone is heard, you eardrum is actually picking up density changes in the air inside the ear, oscillating at 1000 times per second.

A microphone works in a similar fashion. Just as the ear drum vibrates with the air and transfers this energy into nerve impulses, the membrane of a microphone vibrates and translates this energy into electrical impulses.

There are three major types of microphone:

Dynamic microphones are by far the cheapest and most common microphones, especially in project studios and on the stage. These microphones consist of a membrane with a coil of wire attached on one side. In the center of this coil there is a stationary magnet.

Now, when the soundwaves hit the membrane they casue it to vibrate. The vibrations are the same as found in the soundwave. Physics tell us that when a coil of wire moves within a magnetic feild a current in the wire is induced, proportional to the movement. When the membrane moves, the wire moves and a current is induced. now, due to the membrane vibrating in the same way as the soundwaves, the induced current will also be proportional to the soundwaves, with voltage changes representing the wave. Positive voltage peaks are the same as wave peaks, while negative voltages are the same as troughs.Dynamics are good because they are cheap to make. They are also robust which means you can easily put them in more dangerous places, like a kick drum or the top of a snare drum. One of the problems with them is their relatively low sensitivety, seeing as the membrane and the coil are slightly heavy and therefore heavy to move. This also means that they often have a reduced responce in the high frequency bands. Common dynamic microphones are f.eks. the Shure SM57, SM58 and SM7B. Or the Sennheiser MD421's.

Condenser Microphones use a slightly different princial, though the basics are the same.

A condenser microphone uses a condenser, two plates of metal with a gap between them. A current is passed from one plate to the other, and the gap between them has a resistance, which affects the voltage of the current. When the soundwaves hit one of these plates it vibrates (in the same way as the membrane on the dynamic), thus changing the distance between the plates and therefore changing the resistance. The Resistance changes affect the voltage of the signal proportionally to the vibrations of the membrane.Condenser microphones require a current to work, and this current is usually provided by the preamp on either the desk or the interface. Most condenser microphones operate on a 48V current. The current is led through the same cable as the sound signal, so on condensers it is not the overall signal which is recorded, but rather the difference in Voltages from 48V. These differences are proportional to the soundwave and can therefore be recorded.

Condenser Microphones are a tad more expensive to manufacture than dynamics. You can however pick one up for around 2000kr (350USD norwegian prices) new at a store that are acceptable. The good thing with condensers is that their membrane is very light. This means they have an extended frequency pickup range and also react faster to changes in volume (transients.) These characteristics make them the microphone of choice for vocals, overheads on drums and acoustic instruments. In professional studios there are often more condenser microphones than there are dynamics, for this very reason.

The last type of microphone are called Ribbon Microphones. These microphones use a strip of very thin metal that vibrates within a magnetic feild. They are not as commonly used as condensers and dynamics due to their high pricetag and vulnerable ribbon. Ribbons also usually have a diminished pickup of the higher frequencies, usually dipping off at 16kHz. They do however excell at giving the source a very warm and mellow, natural sound amking them a good choice for strings, choirs and very often guitar amps. They are often very good on kick drums, but caution has to be made when placing them. Try to angle them at 45 degrees to the membrane of the drum (meaning pointing at the top of the drum with front angled down). This positioning makes sure the pressure from the air rolls off along the length of the ribbon without stretching or braking it.

As allways, leave a comment if you have any questions. I will be writing a post on common microphones, and microphone characteristics soon. Stay tuned!

The importance of monitors

Far too many under estimate the absolute importance of monitoring. Would a specialist in photography use a PC monitor which distorted and changed the color balance of the image? This would lead to decisions being made that would ultimately be different from the ones that would be made in an ideal situation.

The fact is, my friends, that the quality of monitors you use when mixing and indeed recording audio plays a huge part in the final outcome of the track. I know many who think that they can mix effectively with hi-fi speakers. I myself must admit that I was a part of that deluded fraternity. But when I started mixing in a good monitoring environment it was like being able to see for the first time. Details that are unnoticeable on conventilonal speakers became shockingly apparent, and I was forced to rethink alot of my previous work.

The fact is that conventional speakers colour the sound, to make whatever you are listening to as comfortable as possible. Studio monitors aim to do the opposite. In an ideal world a set of studio monitors must have a completely linear frequency curve between 20-20 000Hz because their aim is not to disguise and change the sound to your liking, but to reveal the bitter and eventually unavoidable truth and therefore give you the chance to improve it.

Please, do not do yourselves the injustice of cuting down on monoitor costs. There is nothing that is truly "good enough" and when it comes down to it, save on other aspects of your studio. It doesn not matter how much fancy outboard gear, or how wonderful you microphones and preamps are if you cannot hear enough to make them work. Do not work blindfolded!

Yours truly,
Robin

MIxing Tools: Compression

Compression is one of the more vague mixing tools, yet the one that few mixes can use without. A compressor is a dynamic prosessor. This means that it processes the dynamic range of a signal. In music dynamics is defined as the difference between the loudest and the quietest parts of the song. A compressor does what the name suggests, and compresses the dynamic range of a signal.

A compressor is actually an automatic gain rider, doing the job that sound engineers had to do with fader riding in the studio/stage/broadcasting studio so as to have a good overall level without letting the peaks overdrive the tape machine/cirquitry and recently AD converters. A compressor takes on this job by reducing the gain of a signal whenever the signal passes a threshold level. This means that all the dynamics over the threshold are reduced, therefore reducing the dynamics of the overall track, enabling the engineer to have a louder average signal without clipping (overdriving the cirquitry).


Well, thats cool I guess. So how does a compressor work? A compressor is one of the most useful tools in mixing when used correctly, and as all tools, can be destructive if used incorrectly. To the right there is a basic software compressor. The controls are the ratio, threshold, attack and release. The ration determines the rate of gain reduction. On the graphical representation the ration determines the slope of the upper half of the curve. A ratio of 1:1 will rueslt in no change while 1:1000 (or infinity) will result in a horizontal curve. The threshold control determines the level at which the gain reduction kicks in. Graphically the threshold is represented as the "break" in the curve. The attack and release controls are the most important controls to understand, as they determine how fast the compressor reacts and when the gain reduction ceases after the signal goes below the threshold again.

In Use
A compressor is most commonly used to create a balance in a mix without having to automate to much. It can "tighten" up a performance that is uneven because it brings the peaks closer to the "valleys." Getting a controlled vocal track for instance, where there is alot of dynamics, you can pull up the quiter sections without having the loud sections become overpowering.

For percussive instruments a compressor can be very useful. By playing around with the attack and release settings on a compressor you can let the initial attack of the snare (f.eks) pass through, while the gain reduction kicks in and dampens the ring of the drum. This method also works the other way round, by having a short attack time and a short release time the attack of the snare will be attenuated while the ring will be left unaffected. Compressors are good as transient shapers, and if used properly can really help a track become punchy, in your face, or pull it back and move it away from the focus point.

PLay around with them, more info will follow. Meanwhile you can send me a mail to robin.bjerke@gmail.com or post a comment if you have any questions.

Peace

Mixing Tools: EQ

One of your most powerful mixing tools is the EQ, short for Equalizer. An EQ is a device that can splits the sound signal into different pieces based on frequency content. These pieces can then be manipulated to change the frequency balance in the specific track (or mix) you are working with.

The name Equalizer comes from the days of telephone design. Researchers found that when a sound signal is sent over large distance by cable the top end of the signal is attenuated (reduced) leaving the resulting sound muddy and dull. They conceived of a device that would isolate the high en of the signal and boost it accordingly, so that the signal would be "equal" at either end of the conversation. The nature of these first eq's contribute heavily to the classic "telephone sound" and a very similar sound can be used by boosting heavily betweekn 1000Hz - 6kHz.

Many people feel a bit stumped about the EQ, so

here is a quick overview of the controls. To the right we have the Sonnox Oxford EQ. This is a parametric EQ, meaning you have different "bands" with the possibility of sweeping them up and down the frequency range. As with most parametric EQ's, and indeed eq's in general, this one features a HPF and LPF (High Pass Filter and Low Pass Filter) These filters work by choosing a cut-off frequency, and then filtering out all the information below that frequency.

Now lets look at the other bands. There are three controls: The Gain control, the frequency control and the Q-Control. The Gain control controls the gain (Obviously). With this controll you can adjust the amount of level boost or attenuation of each band. THe frequency controll adjusts the frequency at which the band will be working, and the Q-controll affects the "width" of the band. Most bands affect a certain frequency and to a lesser extent those around it. The Q controll changes the amount of spread to either side in the frequency range, making the gain change less or more specific. This, of course has a dramatic effect on the sound.

In Use

So there you have the basic workings of an EQ. What now? Well, lets take a look at a couple of hypothetical situations. Let's imagine that we have a Kick drum track with alot of the cymbals in it. The kick is also a little dull and uninteresting. We can use a HPF to roll off the higher frequencies that the kick information does not occupy, thereby reducing the spill from the cymbals, and a slight boost around 600-800Hz should increase some of the attack of the kick thereby making it more prominent in the mix.

Let's take a look at a vocal track. The track is a bit boomy and dull, and there is not enough airyness to the vocalists voice. Well, we can start by using the LPF to roll off all the frequencies below, say 100Hz to reduce the boomy quality, that may have occured due to the proximity effect. We can toggle the shelf controll on the HF, this changes the HF from a bell shape to a shelving band, meaning it boosts or attenuates all frequencies above a certain point. We can boost a little bit around 10kHz or so to bring out some of the air in the vocal, and maybe a boost around 3kHz for presence.

Considerations

Always remember what Joe Meek said, "if it sounds right, it is right." PLay around with the EQ, because it will be one of your most important mixing tools for shaping the sound, and making room in the mix.

A general rule, and one that is hard to follow is that one should try to avoid boosting to much. Every EQ introduces tonal characteristics and most EQ's change the phase slightly of the effected area, so be sensible there. A slight boost with a wide Q can be just as effective as a large boost with a narrow Q, while introduceing less artifacts.

If you have any questions at all, please post a comment or send me a message and I will be only too happy to answer!

Den digitale konseptuelle problemstillingen

Jeg befant meg selv i en interessant situasjon et par uker siden. Jeg og Jock Loveband, head engineeren ved Urban Sound Studios satt inne i kontrollrommet i studio A og snakket om miksing i det analoge domenet. Det slo meg at jeg hadde store vanskeligheter til å begynne med til å sette meg inn i den analoge arbeidsmåten. Min generasjon er barn av den digitale alder, og dette har selvfølgelig påvirket vår forståelse av musikk og musikkproduksjon.

Det at konsepter som hvordan man skal få brukt det analoge utstyret og hvordan man skal mikse en låt analogt fra pro tools var til å begynne med store spørsmål. Luksuser som automasjon, total recall (muligheten til å begynne på en mixs akkurat der du stoppet sist), det å kunne bruke 64 av samme kompressor, og 64 av samme eq blir fort problematiske, krever stor plass og mer penger enn jeg (eller de fleste andre) gidder å bruke.

Men samtidig er det noe veldig beroligende og deilig ved å mikse i det analoge domenet. Mangelen på frihet gjør at man må bestemme seg og holde seg til det man har bestemt. Automasjon blir til en kunstform og man lærer utstyret å kjenne, slik at en kompressor ikke brukes når den kan trenges andre steder, noe som kan resultere i en åpnere og mer dynamisk miks.

Dessverre er denne prosessen veldig krevende å bli komfortabel med, siden den tar bort alle de frihetene man har blit vant med, og ja, har vent seg til. Fordi det var ikke lengesiden man var stuck med det man gjorde. Bruk det digitale til det fulleste, men aldri glem gledene og fordelene ved analog prosessering!

Mvh,
Robin

Hvem er vi?

Tenk deg om. Jeg antar at siden du har snublet innom denne spedbarnsbloggen så deler vi en felles interesse for lyd og teknikken bak. Men har du noengang satt deg ned og tenkt over akkurat hva din oppgave som lydtekniker er? Ihvertfall i studiosammenheng. Ja, vi setter opp mikrofoner, gjør bedømmelser om mikrofonplasseringer for å gi klienten soundet de vil ha, vi mikser, tar opp, lener oss forover og sier inn i talkbacken at vi "Tar'n en gang til." Men når man tenker over det er ikke dette det som karakteriserer en god studiotekniker.

Alle, med litt øvelse og forståelse kan plassere en mikrofon på et sted hvor den låter best, og plassere andre mikrofoner på steder de låter best når summert med andre mikrofoner, sjekke inn nivåene, lene seg tilbake og trykke "3" på numpadden. Det er ikke det at du har gjort dette før, eller er raks på å gjøre disse tingene men det har på hvordan du frstår psykologien bak hele greia.

Oss studioteknikere er skap-psykoanalytikere, og det er vår evne til å lese en situasjon i studio som skiller de gode fra de alminnelige. Det er virkelig på dette feltet at man aldri slutter å lære noe. Resten handler bare om å holde et åpent sinn og prøve ut nye greier, men situasjonsoppfatningen er noe man må streve med.

Se for deg en vokalist, det har vært en lang dag, bandmedlemmene er slitne, produsenten er sliten og du er sliten. Vokalisten synger, prøver, men selv om mikrofonen er satt opp helt perfekt, selv om impedansenivåene i preampen er en utmerket match, selv om alt låter dritfint, så sliter han/hun. Bandet blir frustrert, vokalisten blir frustrert. Det å være i studio er ingen lett ting for en musiker. Om man ikke har vært mye i studio vil man bli veldig påvirket av de "sterile." Hodetelfeonene, glasset inn til kontrollrommet (eller god forbid ikke kunne se de andre og studioteknikern i det hele tatt) der bandmedlemme og produsenten og teknikern og assistenten står og vil at du skal kjøre på og bare bli ferdig for helvete. Det er her teknikerns verdi kommer inn, om det er så lite som et nonchalant smil her og der, eller som jeg har måttet gjøre, å be de andre i rommet pent om å ta seg en luftepause.

Du er den som fasiliterer den kreative prosessen. Det spiller ingen rolle hvor fantastisk flott et studio er om lydtekniker ikke har en anelse om hvem folka i bandet er, hvordan kjemien er og hva som eventuelt kan gjøres for å glatte ut prosessen, fordi det vil alltid være nødvendig, og om det er ingen som har innsikten og erfaringen til å ta tak i det vil det resultere i et dårlig resultat, selv om man kjører signalene gjennom en SSL eller en Behringer.

Velkommen til Lydhjørnet!

Hei!

Velkommen til lydbloggen min. Jeg er en lydtekniker og studioprodusent ved Urban Sound Studios i Oslo. I denne bloggen kan du lese om alt som jeg driver med i studio, mikrofon og opptaksteknikker, mikseteknikker og alt annet som har med lyd å gjøre.

Abboner på denne bloggen og få oppdateringer når jeg legger ut nye innlegg som du kan forhåpentligvis ta lærdom og glede fra!

Vi sees!