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.

Thursday, 23 May 2013

Microphone Madness Part 1

Last week we discussed the importance of cables in a sound system and that they are in fact the most important component of the system.

Second on the list of importance is the microphones you use.

There are two types of microphone commonly used in modern sound systems. Dynamic Microphones and Condensor microphones (There are other types as well but we won't go into them here). Within these two categories microphones have a property that we call "pattern".

Dynamic Microphones are basically a small speaker, a diaphragm inside the mic vibrates with the sound in the air generating a small electrical voltage. Its the exact opposite of the way a speaker works and in actual fact you can hook up a speaker to a mixing desk input and use it as a dynamic microphone (albeit a fairly low quality one).
Dynamic microphones are used for vocals and on many instruments. What makes them particularly useful is the way they respond to bass. The closer the signal source to the microphone the more bass will be in the signal. This is called "Proximity Effect" and is most useful on vocal microphones. You may often see artists pull away from the mic during a high note to emphasise the note and then come in close when singing low to emphasise the low frequencies (think Barry White). The most famous dynamic microphone is the Shure SM58 and SM57 (basically they are both the same mic) which were the staple microphone for vocals and guitars for 30+ years. Today there are a wide range of dynamic mic's available. Dynamic microphones are generally not great at picking up very high frequencies, due to the fact that the large heavy diaphragm needs to be moved by the sound source and high frequencies are low in energy.

Condenser microphones work very differently to Dynamic Mics. A Condenser mic has two tiny plates inside it with a voltage between them. When the top plate is vibrated by the sound source, the capacitance between the two plates changes causing a signal to be generated. Condenser mics therefore need a power source to work and this is the most obvious external difference that you can use to identify a Condenser mic. The power source either comes in the form of an internal battery or power is delivered from the mixing desk down the microphone cable in the form of "Phantom Power".

Because the top plate on a Condenser mic is much smaller and lighter than a diaphragm of a dynamic mic, the Condenser mic is very good at picking up high frequencies. Condenser mics are also far less sensitive to the Proximity Effect so pick up bass signals evenly no matter how close or far away from the sound source the mic is. This is why you most often find Condenser microphones in recording studios, however they also have many applications on live stages.

Below is a summary of where you should use each type of microphone in a live situation.

  • Kick Drum
  • Snare
  • Tom Drums
  • Bass Guitar
  • Guitar
  • Vocals
  • Brass
  • Hi Hats
  • Drum Overheads (Cymbals)
  • Choirs
  • Vocals (think Opera)
  • Brass
  • Kick Drum (when you want more high frequencies)

Thursday, 16 May 2013

Cable Conundrums Part 2

Last week we looked at the important of investing in good cables for your system and what happens if you don't. This week we look at how to maintain that investment in cable to ensure you always get the best out of your system.

Once you have your cables sorted, invest in a good case. A brown suitcase is not a suitable case. Get a road case with wheels and it will force you to treat your cables with the respect they deserve instead of chucking them in the van in a space wherever they will squeeze.

The key to keeping you cables in good nick is learning how to coil them correctly. If you wrap them around your elbow like the un-educated fellow in this picture then your cables will start to look like your mothers vacuum cleaner cord. Notice all the kinks in his cable. When you wrap a cable around your elbow, you actually twist the internal braiding causing irreparable damage. Your cable will never be the same again and if this behavior continues, it will eventually lose its shielding properties and the sound quality will dramatically fall. You may start to notice more noise in your system and eventually the cable will actually fail or even worse, become unreliable.
See the video below on how to avoid this and coil your cables properly.

A good cable tester is also a great investment, check your cables regularly with both a visual and electrical inspection. Also, if you do find a cable with a fault, coil it up and tie a knot in it so that you know it is faulty. Don't put it back in your cable case, keep it separate until you can get it fixed.

If you find you have collected a few cables from gigs and are not sure on their heritage then don't trust them. Don't just throw them into your cable crate and adopt them. Treat them as tainted goods and try and return them to their owner. Generally if cables get left behind and are unclaimed, it is for a reason and you don't want the hassle of adopting someone else's outcasts.

Thursday, 9 May 2013

Cable Connundrums Part 1

Last week I made the bold statement that cables are in actual fact the most important component of any sound system. My reasoning for this is simple. Cables connect all of the components of your system. You have cables connecting to your microphones which connect to your mixing desk. Cables connect your mixing desk to your drive-rack which uses cables to connect to your amplifiers which need great big heavy cables to connect to your speakers.
You even need power cables to get power to all your instruments and equipment around the stage.

How many musicians do you know that turn up to a gig with an old brown suitcase with a whole pile of mismatched and ragged cables stuffed in it? Have you also noticed it is often these same musicians that seem to spend hours setting up, they rush around at the last minute trying to find why the left side of the PA is working but not the right. Or every time the guitarist sings in his mic there is a big crackle through the PA and suddenly you see them riffling through their brown suitcase looking for a replacement cable.
Then when they find the offending cable, it gets chucked back in the brown suitcase and forgotten about until the next gig where it turns up as the main system feed to the amp rack and causes the entire PA to cut in and out during the gig.
Often the PA gets blamed as being dodgy, but the reality is that all the individual components of the PA may be fine, its just the cables connecting them.

If this is you, then my advise is to spend some time sorting your cables out. Often its better to start from scratch with a full new set of system cables. Its easy to spend thousands of dollars on cables, but in reality a functioning cheap cable is better than a non functioning expensive one. My advise is to spend as much as you can afford to on mic cables and speaker cables.
  • A good speaker cable costs at least $100 for a 10m cable.
  • A good mic cable costs between $10 and $40 depending on the length.
  • A good power cable (go for black not orange or yellow) is $40 to $90 depending on length.
If you have time and the skills, make your own mic cables and cut them to the exact length you need for your standard setup. If you don't have good soldering skills, don't even attempt to make your own cables. Even the cheap Chinese ones will be better than a half baked DIY attempt.

Next week we will continue the discussion on cables and discuss how to maintain your investment in cables to ensure they last and continue to perform for a long time.

Thursday, 2 May 2013

Gear Talk

Welcome back to Turn Down the Shit Knob. As summer is the busy season, this Blog has been on hold, but now there is a bit more free time, I'll kick it off again.

I get asked a lot about what gear people should buy to get a good sound.
The answer to this question is never simple and depends on some important factors. The first question I always ask first is "What gear do you have already?"
A sound system is only as good as the weakest point in your system so there is no point in spending $20k on a pair of speakers if you are running them through a rubbish mixing desk.

People are often surprised by what I recommend they spend the most money on in their system. Marketers take advantage of audio naivety and will try and sell you an expensive pair of speakers telling you they will solve all your problems and make your sound system sound amazing.

Unfortunately, the reality is that the quality of your speakers actually has the least impact on the quality of the overall sound relative to the other gear in your system.

Over the next few weeks I'll go through all the components of a sound system and highlight where you should invest the most money and how to tell if the gear you are looking to purchase is good or not (without even listening to it).

My list in descending order of the most important components of your sound system are as follows:
  • Cables 
    • Your system is only as good as the worst quality cable in the system, one dodgy cable is all it takes to ruin a performance, never skimp on cables, ever.
  • Microphones
    • This is where the signal begins, if you have rubbish microphones, then you will be battling uphill to try and get the sound you want. Good microphones unfortunately cost good money and eventually they may wear out.
    • This category extends to DI boxes and any other source of signal.
  • Amplifiers
    • The amplifiers are the engine room of your sound system, don't underestimate the difference a good amp will make to the sound, especially as you start to crank the volume up.
  • Mixing Desk
    • People are often surprised how far down the list the mixing desk is in priority. The reality is that if you have good cables, good microphones and good amplifiers you significantly reduce the 'fixing up' you need to do on the sound. The mixing desk provides the icing on the cake, but if the components above it in the list are rubbish, the best mixing desk in the world won't save you.
  • Speakers
    • There they are, right down the bottom of the list where people least expect to find them. Yip, that's right, the speakers make the least difference to the overall sound quality (assuming they are not blown and function as they were originally designed). People often wrongly focus on the speakers as being the most important component of the system as they are the part that's always visible.
Over the next few weeks I'll go through this list and and offer advice on how you can find the best components for your money and how to tell if what your are buying is actually good or not based solely on the published technical specs. Hopefully I will convert the technical jargon that most people gloss over and ignore into plain English that you can understand.