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live sound

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Microphone Types and Uses

July 28, 2010

Hal Leonard Recording Book

Microphones & Mixers Book & DVD

Definition:  Microphone — or mic — converts acoustic energy into electrical energy, resulting in an audio signal.

Rather than going into the scientific details I am going to outline the different types of microphones and what they’re used for:

Dynamic Microphone:   Most commonly used for live sound and known for its durability.  It’s also the best choice for the high volume levels of bass guitar, bass drums and amplifiers.  For optimal performance, this mic should not be placed any more than one foot away from the sound source.  Otherwise, the result could be a thin sound with less color and clarity.  Some popular dynamic microphone choices are:   Shure SM57 and SM58;  Sennheiser 421 and441;  Electro-Voice EV PL80; and the Audio-Technica M4000.

Condenser Microphone:  Most commonly used for recording lead vocal tracks, acoustic guitars, pianos, and live strings, the condenser is known for its ability to capture the smaller nuances of sound.  It has a very quick, accurate response as well as a clarity that cannot be achieved by other types of microphones.  While not as rugged as a dynamic, this mic is capable of capturing a broader range of frequencies from a greater distance than any other type.  Popular condenser microphones include:  Shure KSM27 and KSM32;  Electro-Voice Bk-1;  Sennheiser MKH40 and MKH80;  and the Neumann KMS105.

Ribbon Microphone:   Known as the most fragile of the different microphone types, some sound engineers are hesitant to utilize this mic in any live setting for fear of damaging it.  Despite its lack of ruggedness, the effects and quality of sound from a ribbon microphone are very similar to those of a dynamic in that they tend to enhance the higher frequencies of the sound and perform best when placed within close proximity of the sound source.

As you can probably tell, dynamic and condenser mics are the most common and will likely be what you and/or your engineer are working with.  An excellent resource for learning about microphones and microphone technique is the

Hal Leonard Recording Method Book/DVD Volume 1 – Microphones & Mixers, Pepper #10040995.

Directors' Toolbox

Mixing Live Sound

June 29, 2010

Mixing Live SoundHere are a few handy tips and some basic information on what goes into setting up and mixing live sound:

  1. A “mix” is created by combining the separate audio signals from individual voices or instruments into one.
  2. Usually two mixes, sometimes more, are created for any given performance – one for the performer(s) and front rows and one for the rest of the audience.  What you hear may differ from what they hear.
  3. In larger venues with multiple speakers, the sound must be mixed and synchronized in such a way that prevents the performer’s monitors from overpowering the overall sound and vice-versa.  Ever notice that the sound booth at a concert hall is often located in the middle of the floor of the venue?  That’s because they’re in charge of what the audience hears.  A second engineer will often take care of what the performers hear.
  4. Sound levels during the performance will likely need adjustment throughout the performance.  Communicate with your engineer on any ideas or concerns you may have regarding sound levels.  Perhaps you have far more trumpeters than flautists and want to make sure the flutes aren’t drowned out.  Or, maybe you have a diva in your midst who attempts to turn her favorite song into a personal showcase by drowning out the rest of the group.  Most of the time there are adjustments that can be made by simply moving equipment or adjusting levels.

Keep in mind that some venues are going to be much easier to work with sonically than others.  Mixing is only one aspect of what goes into achieving quality sound.  Microphone choices and placement also play a huge role in what you, the performers and audience hear.

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Directors' Toolbox

The Job of a Sound Engineer

June 1, 2010
The Basics of Live Sound

The Basics of Live Sound

Chapter 1 of The Basics of Live Sound by Jerry Slone defines a sound engineer as “A person who brings together separate sounds to create one sound.”  Simple enough, right?  The reality is that a sound engineer can be responsible for a wide range of things, from setting up and running equipment, to mixing and mastering multi-track recordings. They’ve also been known to break out the occasional soldering iron to save the day when a renegade wire attempts to disrupt a performance.  The talents of a sound engineer are not limited simply to recording a band in the studio or monitoring a live concert.  There are many areas where we encounter their work on a daily basis, including  TV and radio commercials, video game audio design, movie audio post-production, or even PA systems for public speaking.

Here is a short list of the various types of engineers with an overview of their duties:

Recording Engineer – Records sound either in a studio or live setting.

Mixing Engineer – Combines the audio from a multi-track recording into a single mix by adjusting volume and adding effects.

Mastering Engineer – Creates the final mix of a recording in preparation for mass production, using equalization and compression techniques.

Live Sound Engineer – Works with the various aspects of a “Sound Reinforcement” system, including planning and setting up equipment, mixing and monitoring sound, and adding effects.

Moving forward, my blog series will primarily focus on the aspects of live sound, as this is what most of you are, or will be, dealing with as musicians and music directors.  Remember, your sound engineer is your friend and having a better understanding of their world will help you achieve the sound that you want through the art of communication.

Directors' Toolbox

What is Sound?

May 7, 2010

Before touching on equipment or technique, it is important to understand exactly what sound is and how it works.  While there are far more scientific aspects involved with the subject of sound than what I am going to cover here, my goal is to break things down in a way that musicians will relate to.

A great definition of sound comes from mediacollege.com, which says:  “Sound waves exist as variations of pressure in a medium such as air. They are created by the vibration of an object, which causes the air surrounding it to vibrate.  The vibrating air then causes the human eardrum to vibrate, which the brain interprets as sound.”

Sound waves are created much in the same way as waves in water.  If you place your finger in a tub of water and move it back and forth, you immediately begin to see ripples forming and moving outward from the point of contact.  These ripples exist because:  a)  you, as the source, caused a vibration;  and b)  the vibration you caused had a medium to travel through — the water.  With sound, you have many possible sources — e.g. a hammer striking a piano string, someone’s voice resounding, a mallet striking a drum — which produce vibrations that travel through the air and finally to your eardrum.  Your eardrum is an incredibly sensitive membrane that will vibrate at even the slightest pressure created by sound waves.  The waves then travel through the inner ear, which is lined in rows with tiny hairs that act as receptors.  The vibrations pass along these hairs, reacting to the frequencies of the waves that pass through, and produce the sensation of hearing.  Hearing loss can occur when these tiny hairs are bombarded with too much pressure all at once, or too frequently, thus causing the hairs to essentially lie down flat and no longer be able to experience the sensation of sound waves traveling through.

Each sound wave has its own unique set of characteristics that are primarily defined by three things:  1.  Wavelength  2.  Frequency  3.  Amplitude

Wavelength

Wavelength — Measurement from the crest of one wave to the crest of the next.  High-pitch sounds have short wavelengths, while low-pitch sounds have long wavelengths.

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Frequency

Frequency – The number of sound wave cycles completed per second.  A cycle is one complete peak and fall of a sound wave or one vibration of the vibrating source.  Frequency is measured in Hertz (Hz).  The average human ear picks up on frequencies (or pitches) that range from 20-20,000 Hz.  The low sound of a tuba vibrates around 25 Hz, whereas the frequency of a C piccolo lands right around 587 Hz.

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Amplitude

Amplitude – Essentially the height of the wave from its equilibrium point.  Amplitude refers to the intensity or loudness of the wave and is measured in decibels (dB).  The average conversation is spoken at about 70 dB, whereas levels around 130 dB would be akin to standing next to the engine of a jet.  The sound pressure of 130 dB is such that it will cause pain and potential damage to your ear drum.

If you would like to delve more into the subject of sound waves and their characteristics, then www.mediacollege.com offers supplemental information as well as audio examples of some of the things we have covered here.  There’s also a great (and inexpensive) book by Jerry Slone called The Basics of Live Sound that offers a great crash-course without all of the engineer “jargon.”

Now that you have an understanding of what sound is and how it works, we will next discuss what the job of a sound engineer entails.  Stay tuned!

Archive

The Challenges of Live Sound

April 12, 2010

How many times have you attended the concert of a performer that you love and thought to yourself, “Wow, I really wish that I could hear the vocalist better” or “Does that guitar really need to be so front and center?”  Being one who frequents both amateur and professional performances, I can honestly say that this seems to be a growing trend that spans even beyond the rock genre.  For fear of sounding too much like a critic, I want to express that I absolutely recognize how challenging working with sound is, especially in a live setting.  There is so much more that goes into it than most people realize and one engineer is going to face different challenges and have a different approach than the next.   Just as we as music listeners have preferences in what types of music we like to hear, engineers often times have their own idea of what a band or artist should sound like.  But I think that all can agree that the goal is to make it sound good.

The finest display of live sound artistry that I have experienced was at a small venue in Kalamazoo, Michigan.  The artist performing was Loreena McKennitt, along with her nine-piece band of incredibly versatile and talented musicians.  Between all ten of them, nineteen different instruments, not counting vocals, were utilized to paint the intricate melodic pictures that Loreena’s songs are famous for.  If you know anything of Ms. Mckennitt’s work, you are aware that she has a fondness for culturally diverse and rather rare instruments.  How often is it that you experience the unique sounds of a Hurdy Gurdy, Celtic Bouzouki, or a Constantinople Lyra, all in the same performance?  Combine these with your more standard piano, guitar, percussion line-up and you have a bit of a challenge for any live sound engineer.  However, the two men standing in the small sound booth near the back of the auditorium were able to pull off a near-perfect sonic blend that beautifully represented each and every one of those instruments, regardless of its size or inherent amplitude.  To top it off, not a single lyric sung was lost in the vast array of sounds — that impressed me the most.  In fact, I loved it so much that, rather than rushing out the door at the end of the show to see if Loreena and company were going to come out to sign autographs, I walked over to the sound booth to express my enthusiasm to the two men standing there, packing up their equipment.  My compliments were received with shy smiles and mumbled “thank you’s,” so I didn’t linger too long so as not to make them uncomfortable.  I can only hope that my words were encouraging and that they are still out there practicing their craft for the benefit of performers and audiences alike.

In the coming months I will be offering some basic tips and advice on how to achieve quality sound for your choir, band, or orchestra.  Topics such as sound basics, choosing the right microphone, microphone technique and sound levels will be covered.  If there is anything sound-related in particular that you would like information on, please let me know and I will do my best to accommodate.  While my advice will not be the end-all, be-all of sound methodology, I am happy to at least try to point anyone who has questions in the right direction.