Thursday, 30 May 2013

Microphone Madness Part 2


Within the two types of microphone we looked at last week, each mic will have a property that we call "Polar Pattern" or "Pickup Response". This property determines where a microphone picks up sound relative to the direction it is pointed. There is a wide range of pickup patterns and the pattern is exceedingly useful in controlling and enhancing sound. Using the right mic with the right pickup pattern for the job will have a massive impact on the quality of sound.

The various pickup patterns available include:
  • Omnidirectional
    • Picks up sound equally from all directions. Basically it doesn't matter where you point the mic it will pick up sound from anywhere in the room. This can be good and bad and generally you don't want omnidirectional mics in a live environment. If you point an omnidirectional microphone at a guitar cabinet but the guitar cabinet is sitting right next to a giant bass cabinet, then you will get a lot of the bass sound in the guitar mic. This makes it hard to control the sound if the bass is too loud.
  • Bi-Directional
    • These pickup sound from the front and back but not from the sides, again these are not much use in live sound because if you put a Bi-Directional microphone on a vocalist, but the other side of the microphone is pointing at a stage monitor then you are going to pickup all the noise from the stage monitor which will cause feedback.
  • Sub-Cardiod
    • These mics pickup sound from the front and a little bit of sound from the back, we usually avoid these in live sound as well unless we are mic'ing the inside of a drum or something where we want to pickup the sound of the drum shell. Sub-Cardioid mics are also fairly prone to feedback.
  • Cardiod
    • These are the most common and useful mics in live sound. They pickup sound at whatever you point them at and reject  most of the sound coming in from the other direction. This is most useful when you have other noise sources on stage that you don't want to pick up, for example stage monitors.
  • Hyper and Super-Cardiod
    • These mics are really directional but do pickup a little from the back as well. You will find that moving slightly off the front of the mic results in a dramatic reduction in sound level. These should only be used on vocalists who really know their stuff or for very specialist applications by a sound engineer.
  • Shotgun Mic
    • These mics only pickup sound that is coming directly from the direction you point the mic, any sound from the sides is actively rejected. They are most often used in theatre, television or stage shows.
Dynamic Microphones degrade over time, especially when they are used for vocals where dirt and grime from saliva builds up on the diaphragm making it heavier and slower to respond. There is no easy way of cleaning a mic diaphragm so the best you can do is regularly clean the grill and windsock to limit the damage.

If you are vocalist, its is often a good idea to buy your own mic and don't share it. This will also reduce the chances of picking up some nasty bug from a shared microphone. If you are going to buy your own mic, talk to a sound engineer about which mic to choose to suit your voice. There is no point skimping if you are going to buy your own. If in doubt, buy a Shure Beta 58 as that is still the industry standard fallback mic for vocals.

Be wary about wireless microphones. So many times I see artists with wireless microphones that sit in the mic stand all night and don't move. Ask yourself if you really need the mobility and portability of a wireless mic? No matter how much you spend, a wireless mic will always sound worse than the equivalent wired version of the same mic. Always use wireless as a last resort when there is no other option and a portable solution is required. Unless you are leaping across bar tables or stage diving into a mosh pit while singing at the same time, you will always sound better with a wired mic.

Be wary of 'cheap' microphones. You get what you pay for and cheap microphones often have un-desirable or unpredictable pickup patterns that will cause you a world of pain when it comes to feedback. Stick to the reputable brands and don't go for the bottom of the range, usually the mid range offerings from all the manufacturers offer the best value for money and quality for your dollar.

Good brands are Audio Technica (avoid their cheap stuff), Shure (avoid the PG and SLX series), AKG (only their expensive stuff is good, avoid the cheap stuff), Sennheiser, Beyerdynamic, Crown and EV.

If you have some extra dollars to spend, check out the offerings from Heil, Blue, Rode and Neuman.

Brands to avoid are Behringer, Line 6, and  Peavey.
I am personally on the fence about Audix, but some people rave about them.

Picking the right microphone for the job will make a huge difference to your sound quality. It also saves you having to spend a lot of time adjusting the sound on a mixing desk.