EQ Tips for Keys, Pianos and Synthesizers

When it comes to EQ’ing keys, there is a big difference between what you will do for electronic keys/synthesizers and acoustic pianos. So, let’s go through both.

Keys & Synthesizers

Electronic keys don’t often need a lot of EQ, but you can fine-tune the sound by adjusting a few fundamental frequency ranges.

Tip: Clean up the muddiness.

Keys and synths can get a bit muddy in the 400-600Hz range. Use a peaking filter with a Q value around 4 in this area to clean up the sound, especially when it is layered with other instruments.

Tip: Help the keys ‘cut through’ the mix.

If you need the sound to cut through the mix, try boosting slightly in the 1-2 kHz range. Or, you may even need to cut this area to make room for other instruments.

The 3-4 kHz range is where the primary presence and clarity can be found. Boost this area a little if necessary. Or, you can cut this area to make the tone a bit darker.

Acoustic Pianos

Regarding pianos, there are many different types and sizes that will have a range of tonal properties, so these tips will depend on size, playing style and miking techniques.

Tip: Cut the boominess.

Pianos can tend to be really boomy in the 100-200Hz range. The best way to fix this problem is with a low shelf filter at about 200Hz and cut 3-6dB.

This can also help reduce feedback or other low end resonance from drums or nearby instruments on stage.

Tip: Brighten the tone of the piano.

You can brighten the tone and help the piano cut through the mix by using a peaking filter in the 3 kHz range with a Q value around 4 and applying a slight boost.

Keep in mind, too much emphasis in this range can exaggerate distracting elements like damper and string noise.

The Ultimate Guide for Choosing Audio Cables

Does your sound system buzz, hiss or make some other kind of unwanted noise? The problem is most likely rooted in bad cables.

Regardless of how good your mixer, amps or speakers are, you will never get a good sound if you don’t have the right cables.

You don’t need the most expensive cables to achieve the quality of sound you desire. But, you do need to see cables as something worth investing in.

Below, you will find the cables I recommend. I have used these in my church for years and I am very happy with the results.

Balanced vs. Unbalanced Cables

Unbalanced cables have two wires: one that carries the signal and a common ground. They are also shielded to help protect from unwanted hum and other noise. Instrument cables are typically unbalanced as well as many patch cables. They are used to connect high-impedance signals (guitar, keyboard, guitar pedals, etc.) to an amp, mic preamp or direct box. Unbalanced cables should not be longer than 25 feet.

Balanced cables have a third wire that also carries the signal, but in reverse. This causes any unwanted noise to be eliminated, making them ideal for longer cable runs. Balanced cables generally have either a XLR or TRS connector.

While in a few cases balanced and unbalanced cables are interchangeable, it is the output source you are connecting that will determine which type is needed. For example, microphones usually require a balanced cable as do direct boxes.

Direct Box: Converting Balanced to Unbalanced

Recommended Direct Box: Radial Pro DI Passive Direct Box

In short, a direct box converts an unbalanced signal (i.e. from a keyboard) to a balanced signal so it can then be sent over a long cable run back to your mixer. Considering your keyboard player is probably more than 25 feet from you mixer, a direct box is your solution to getting the signal back go the mixer without unwanted hum or noise.

Common Connectors

 TS (aka 1/4”)

TS connectors come in 1/4” and 1/8”. They are used for unbalanced operation with instrument, patch and speaker cables. The easiest way to tell them apart is they only have one ring (usually black) on the shaft of the connector.

 TRS

TRS connectors come in 1/4” and 1/8”. They are used for balanced or stereo operation with microphone or patch cables. They have two rings on the shaft of the connector, making it easy to differentiate from a TS connector.

 XLR

XLR connectors are used for balanced operation with microphone cables. They are most widely used with microphones, but you will also find them on balanced patch cables and DMX lighting cables.

 Speakon

Speakon connectors are used to connect amps to speakers with speaker cable. They are becoming increasingly popular because they lock into place and therefore cannot become accidentally disconnected.

 Banana Plugs

Banana plugs are used to connect amps to speakers with speaker cable. You will most often find them on the end that connects to the amp, which enables you to easily set up bridge mono operation.

Instrument Cables

Recommended Instrument Cable: GLS Audio Instrument Cable

Instrument cables connect a guitar, bass, keyboard or other electronic instrument to an amp, preamp or direct box. They carry low-voltage signals and generally have 1/4” connectors. They are considered unbalanced cables, which means they are susceptible to noise and should be kept as short as possible (certainly under 25 feet).

An instrument cable should never be used as speaker cable. If used as a speaker cable, the quality of sound will suffer and the cable may get hot enough to melt the jacket.

Microphone Cables

Recommended Microphone Cable: GLS Audio Microphone Cable

Microphone cables are generally understood correctly, mainly because of their unique XLR connector. They are shielded and balanced which effectively keeps unwanted noise at a minimum (especially for long cable runs). They are used to connect microphones, direct boxes and other low-impedance signals to the mixer.

Patch Cables

Recommended Patch Cable: GLS Audio Patch Cables

Patch cables are used to connect various audio components together. They are generally short in length and may be balanced or unbalanced, depending on their application. For example, when connecting a series of guitar pedals, you will use unbalanced patch cable considering the signal coming from the guitar is also unbalanced.

Patch cables come in all shapes and sizes. You can get almost any kind of connector, including XLR, 1/4”, TRS and RCA. When choosing a patch cable, you must first determine if the audio source is balanced or unbalanced. Then, it is just a matter of getting the right length and connectors. Keep in mind; the only balanced connectors are TRS and XLR. The others indicate an unbalanced cable.

Speaker Cables

Recommended Speaker Cable: GLS Audio 12AWG Speaker Cables

A speaker cable is an unbalanced cable that has a much heavier gauge (more wire) than most other audio cables. The reason they need heavier wire is because they carry a much higher voltage than microphone or instrument cables.

Many confuse a speaker cable with an instrument cable, especially when they have a 1/4” connector on both sides. However, they are not the same. An instrument cable is not capable of handling the high voltage that is pushed from the amp to the speaker. It may seem like it is working, especially at low volumes, but your amp is having to work extremely hard to push the signal through such a small conductor. Eventually, the instrument cable will heat up, melt the jacket and cause a short circuit – potentially ruining both the speaker and the amp.

Proper Speaker Cable Gauge

When buying speaker cables, the gauge of the cable becomes an important factor to consider. Keep in mind, the lower the number the more ‘thick’ the cable is. So, a 12-gauge cable is thicker (has more wires) than a 14-gauge cable.

A cable that is too ‘light’ (gauge is too high) will result in amplifier power being wasted. It will also cause a loss of low-frequency performance. On the other hand, the only downside to having a ‘heaver’ cable than you need is excessive cost.

Following is a chart to help you determine what speaker gauge you need. I have found that 12-gauge is most often the appropriate choice for church sound systems.

How to get started with a click and backing tracks for your worship band by Jake Gosselin

Worship Leading

I led worship for years without using a click track or backing tracks.

I used to think things like:

“It limits musical freedom.”

“Our band members are not skilled enough to play with a click.”

“It sounds too ‘produced’”

“I do not have time in my weekly preparation for a click and tracks.”

Those were some of the thoughts and objections that ran through my head as I considered whether or not it was worth implementing a click and backing tracks with my worship band.

Then I finally arrived at a place where I felt like I was stagnating as a worship leader and I wanted to challenge myself and my band. That’s when I started doing some research to learn what type of equipment and knowledge I would need to begin using a click and backing tracks in worship. 

I knew I was going to need in-ear monitoring, and I heard of software like Ableton Live, but it all seemed intimidating. How was I ever going to convince my band, which consisted mostly of people 20 years older than me, to play with backing tracks, let alone start using in-ear monitors?

Whelp, both of those things happened. It was not easy and did not occur overnight, but in a couple of months I had my whole band on in-ear monitors, playing with a click and backing tracks, and I even began automating ProPresenter and lighting. My only regret is that I did not learn to do these things sooner!

A lot of worship leaders struggle with “staying fresh.” Playing mostly the same songs every week in the same venue for the same people can get creatively stale. I also have a firm conviction that the local church should be a wellspring of excellent and inspiring creativity that makes a powerful impact on the unchurched. 

When I learned how to use a click and backing tracks in worship, it opened so many doors of creativity and drastically increased the excellence of our worship experience.

But getting started was tough. That’s why I want to share my journey with you and provide you with a clear roadmap of how to begin using a click and backing tracks in worship. This is what I wish I could go back in time a couple of years and teach myself to save hours of research and headache.

Here are the three steps of the process I am going to cover.

1. The gear

2. The software

3. Implementation

I also have a complete online course on how to implement a click and tracks in worship. You’ll find the course inside Worship Leader School. Click here to learn more and join today.

1. The Gear

First, let’s talk about the gear you are going to need. Here is a simple diagram of everything that needs to happen to use a click and backing tracks in worship. First, you are going to need a device that is going to play your click and backing tracks. If you are a beginner, the simplest device to use is an Apple iPhone or iPad. 

Sorry Android users, the app I’m going to show you later does not support Android. If you do not have access to an Apple device, keep watching this video, and I’ll show you towards the end how to get up and running with Ableton Live on a Mac or Windows computer for free.

As you can see in this diagram, we need the signal to get from your smartphone to split into a stereo feed with the click on the left and the backing tracks on the right. This is important because at our front of house mixer we need to have separate control of the click track and backing tracks. 

The click track and backing tracks are both sent to your band’s monitors, but we want only the backing tracks to come through the house speakers. Your congregation does not want to hear a click and cues. 

The cheapest piece of gear to split the signal coming from your phone, tablet, or laptop, is this 3.5mm TRS to dual quarter inch cable you’ll find on Amazon for five bucks. You’ll plug the 3.5mm TRS end into your device and then plug the red and black quarter ends inch into two separate channels on your mixer. The red will be the right channel containing the backing tracks, and the black will be the left channel containing the click. 

If you would rather have your playback device on stage, then you will need a stereo DI box which you can plug the dual quarter inch ends into, and then out of the box you will have two XLR cables that run to your stage snake and then to your soundboard.

Now that the signal from the smartphone is at the soundboard, you need to send the click and backing tracks to your musician's monitors. This is why it is important to have in-ear monitors. You do not want the click track to come through floor wedges. 

If you do not have in-ear monitors, I recommend checking out this article in which I cover what monitors to get based on your budget. At the very least, you need to have your drummer and worship leader using in-ears. That’s what I did when our church could not afford to buy enough in-ear monitors at once. This worked great, and I highly recommend going this route if budget is an issue. 

Now your church audio engineer will be able to mix in the backing tracks to the main mix in the house as well as send your band the levels they need for the click track.

That is all you need for gear to run backing tracks. Assuming you have a smartphone or tablet and a stereo DI Box you can get up and running with a click and backing tracks with a minimal investment.

2. The software - Playback or Prime

I recommend two apps for running a click and tracks in worship: Playback by Multitracks or Prime by Loop Community. Either app is great choice and it’s up to your personal preference for which user interface and ecosystem you prefer. Check out this article where I provide an in-depth analysis of the two.

Here’s a brief walkthrough of getting up and running with the Playback app. Prime works the same way. I’d recommend downloading both to figure out which is best for you.

On your smartphone go to the Apple App Store and download Playback by Multitracks.com. Open up the app and sign up for a Multitracks.com account. This site is a great resource for downloading high quality, and original backing track stems from bands like Hillsong, Elevation, and Chris Tomlin, just to name a few.

I also recommend purchasing tracks from Loop Community. They don’t have all of the original master tracks for popular bands like Hillsong, but they do have budget-friendly options and community sourced tracks from worship leaders who produce custom arrangements.

Once you are in the Playback (or Prime) app, take some time to get acquainted with it and its features. Click the gear icon in the upper right and then select “manual” for a walk through. The capability of this app is astounding, and I cannot think of a better way to start using a click and backing tracks. By default, you will be using the free intro version, but you can upgrade for some more advanced features.

In the Playback app, download the free Play of the Week so you can start using the app and testing it with your sound system. Make sure auto-pan is enabled in settings so your click track and backing tracks are separated into left and right channels.

In the end, I want to emphasize how important it is to try both Playback and Prime for yourself. The biggest benefit to the Playback ecosystem is the track rental program. But Prime has some significant benefits such as the app being free and they even provide free cloud storage for your tracks. Many worship leaders utilize both Playback and Prime in their workflow. You may find yourself doing the same.

3. Implementation

Now that you have the gear and software for running a click and backing tracks, it’s time for implementation with your worship band. Here is what I recommend doing to transition a worship band that has never used a click and backing tracks to using the setup we have just discussed on a weekly basis.

First, communicate your intentions and the reasoning for using a click and backing tracks. You could explain how it’s going to give the band a fuller sound and it is going to increase the quality of their musicianship. 

Next, spend one-on-one time practicing with the click track with your drummer. He or she will be the most important musician to make sure they can play with the click. Once you know your drummer is going to be comfortable, allot extra rehearsal time with the full band to introduce the click and backing tracks. Let the band know ahead of time that you are going to first try using the setup only in rehearsal and then implement it on the weekend once you know everyone is comfortable.

A lot of volunteer musicians get nervous when they hear you want to implement technology like this because they worry they are not skilled enough to keep up. 

Playing with a click and backing tracks is one of the best remedies for poor musicianship and a sloppy band because it provides an extra sense of guidance while at the same time forces everyone to play on tempo, making the band tighter. 

The key for implementation is to take it slow and not overwhelm your band.

4. Advanced Techniques

Once your band is used to playing with the Playback app, here is what you can do to continue to challenge yourself as a worship leader and bring production quality to the next level. 

First, learn how to build your multitrack sessions in Ableton Live. This software is a digital audio workstation that will open up a lot more potential for improving your worship production and creativity. You can still download backing tracks from Multitracks.com or Loop Community, but assembling them in Ableton is a bit advanced. I have a video on how to do this.

Once you are familiar with how to use Ableton Live to run your click and backing tracks, I recommend learning how to control ProPresenter from Ableton. Imagine if you never had late lyric or background cues in worship ever again? Ableton Live automation makes that possible. You can also automate lighting software. Check out my full Ableton Live setup here.

I covered a lot in this article and it may seem a little overwhelming. If you’d like more help and guidance implementing a click and tracks in worship, check out Worship Leader School. It’s a membership site where you’ll find all the essential training, advice, and support you’ll need to plan and lead worship. Inside the school is a complete step-by-step course on how to setup a click and tracks for your worship band. Click here to learn more and to apply to join Worship Leader School.

That's how to get started with a click and backing tracks for your worship band. I hope this saves you some time and gives you the confidence to implement these tools at your church. I believe any worship leader at any skill level and with nearly any budget can accomplish this. If you have not started using a click and backing tracks, what's keeping you from doing so? Share your love and opinions in the comments below and let me know if you have any questions.

 

Tagged: ableton, beginner

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How to Make Lead Vocals Sound Amazing

I have been in many church worship services where you can hardly hear the lead vocal. To tell you the truth, I have even led some of these services.

There are many causes to this problem, so let’s go through the chain of events so you can get your lead vocal sounding amazing.

First, examine the source.

This may seem obvious, but the first thing you need to check is if the lead vocal is actually projecting. In worship, you often come across people who have little to no training or experience, so they have yet to discover how to put the ‘umph’ behind their singing voice.

Generally, they just need to learn proper breathing technique or how to open up their throat and let the sound move freely. I found this great post on breathing: Learning to Breathe.

Next, pick the right microphone.

Not all microphones are created equal. Yet, we often give every vocal the same one. I like to have three different microphones on hand Wharfedale DM series, Sennheiser mics, and the good old. Keep in mind; you should level the EQ on the soundboard before running this test so you have level testing ground.

Don’t forget about the importance of microphone placement.

You should address this before testing microphones as microphones react differently depending on how close or far away it is from the mouth. The microphone should be no more than 1″ from the mouth. Also, never put your hand over the mesh part of the microphone.

Now, you must properly set EQ.

Have you ever moved around EQ knobs without really knowing what you are doing? I know I have. And it usually just makes the situation worse.

Luckily, it is not as hard as you might think. For tips on how to EQ vocals, check out this post:

The Most Important EQ Techniques for Church Sound

Don’t forget the compressor!

Vocals have a wide dynamic range. To get a lead vocal loud enough to cut through the mix, you will often have problems with it getting too loud during bigger parts of the song. So, you can either memorize when these louder parts are coming, or invest in your best friend: the compressor.

Basically, a compressor narrows the dynamic range so you don’t have to worry about it poking out too much, but you can still get those quieter moments to cut through. Here are some baseline settings for vocal compression to get you started:

• Set the attack and release to ‘auto’ (or, set attack to 30ms and release to 300ms)

• Set the ratio to 3:1

• Use the soft-knee setting if available

• Set your threshold while the vocal is singing so that so that the gain reduction meter rarely reads more than 6dB

To learn more about compression, see How to Set a Compressor for Vocals.

Get the Vocal EQ Cheat Sheet

You are well on your way to making the lead vocal sound amazing. It will definitely take some work, as every sound system and vocal is different, but don’t give up.

Speaker Impedance Changes Amplifier Power

SOUND FACTORY Speaker tips. 

Speaker impedance changes amplifier power output. In fact, your amplifier power could be nearly half or double its capacity – depending on the impedance of your speakers. But how much should this concern you?

Impedance is measured in ohms. The Omega symbol (Ω) is used for shorthand.

Amplifier Output Power

Let’s say we have an amplifier. The specifications might say the output power is 100 watts RMS at 8 ohms.

Notice the power output (100 watts) is at a specified load (8 ohms). This is telling us that with an 8 ohm speaker, the maximum output power will be 100 watts.

An Ideal Amplifier

If our sample amplifier were an ideal amplifier, then we can also calculate¹ that:

• With a 4 ohm speaker, the maximum output power will be 200 watts.

• With a 16 ohm speaker, the maximum output power will be 50 watts.

The above shows that for an ideal amp, halving the impedance doubles the power output. Doubling the impedance halves the power output.

Halving speaker impedance doubles amplifier power.

Doubling speaker impedance divides output power by half.

An ideal amplifier is an amplifier which is theoretically perfect. Of course, such an amplifier does not exist, but they are useful when explaining how speaker impedance changes amplifier power.

In summary, in an ideal amplifier, the current from the amplifier will depend on the speaker impedance (ohms). The lower the speaker’s impedance (in ohms) the greater the current that can be drawn from the amp, which means the greater the power.

Real World Amplifiers

The above calculations work well for an ideal amplifier, and help show how speaker impedance changes amplifier power output.

In reality, amplifiers cannot maintain the theoretical output levels as calculated above. This is because the power supply on most amplifiers cannot maintain the maximum power when driving the lower impedance speakers.

In a real amplifier, the above principles still hold but the theoretical values will not be achieved. The power output will be increased with lower impedance speakers, but the maximum power output will not be doubled when the impedance is halved.

As an example of a real world amplifier, let’s look at the specifications of a popular PA Amplifier purchased at Amazon through this site, the Crown XLS1000.

 

This shows that for this amplifier, with both (dual) channels used at the same time, the maximum power output of the amplifier changes as the speaker impedance changes:

• With an 8 ohm speaker, the maximum output power will be 215 watts.

• With a 4 ohm speaker, the maximum output power will be 350 watts.

• With a 2 ohm speaker, the maximum output power will be 550 watts.

This example shows that in a real world amplifier, the principle of “speaker impedance changes amplifier power output” is true, just not as much as in an ideal amplifier.

Please note: this amplifier is designed to work with a speaker’s impedance as low as 2 ohms. Most HiFi amps are only designed to work with a speaker impedance of (or above) 4 ohms.

So What?

So what should you do with this marvelous knowledge? If 4 ohm speaker gives you nearly double the power of 8 ohm speakers, should you only use 4 ohm speakers?

Answer: Yes, and No.

4 ohm speakers are used widely in the car audio industry, as they want to squeeze every bit of power capable from a fixed voltage (~12-14 volts from a car battery). They also mostly design and build their amplifiers to cope with 4 ohms and often 2 ohm loads.

However, it may not be wise to run your Hifi amp flat out at 4 ohms. The reason being, it may mean you are running your amp at or beyond its design limits. The cheaper the amp, the closer you are likely to be at the limits of the power the power supply can cope with. Better to use 6 ohm or 8 ohm speakers, and let your amp comfortably drive them without reaching full capacity. This is similar to a car: better not to constantly drive with the motor at full revs. Interestingly, most Hifi speakers are 6Ω or 8Ω.

A common method of changing speaker impedance is by adding another speaker, either in series or in parallel with the existing speaker. While this will change the output power of the amp, the speakers will share that power. For more details see How Multiple Speakers Share Power.

Most modern amplifiers will, if they are overloaded,  either turn themselves off or reduce the output to protect themselves. However, it is wise not to rely on this self-preservation circuitry, best to design your system conservatively.

Keep in mind that all this is describing the maximum power output of an amplifier. If you don’t run your amp anywhere near full volume, then all this is fairly much irrelevant.

Also keep in mind that doubling the amplifier power only increases the volume by around 23%.  To double the volume you need around ten times the power. For an explanation of this, see the article on Double Amplifier Power does not Double the Volume. 

If you need maximum level from your speakers pay attention to the sensitivity in the specifications Using a speaker with a sensitivity of 90dB (1W/1m) compared to another speaker rated at 87dB (1W/1m) is the same as doubling the amplifier power driving the speaker. For more details on this see the article Understanding Speaker Sensitivity.

While speaker impedance changes amplifier power output, it is not a major consideration for most users. It only becomes relevant when running your amplifier at full power, and then it is best not to run it too close to its design limits.

Never use a speaker (or speakers) below the minimum impedance the amplifier is designed for. If you hear any distortion, it is an indication that major trouble is just around the corner – turn the volume down, eliminate the distortion and consider a redesign of the system.

Top 3 Things All Church Sound Techs Should Know

So many of us got our start in audio by simply being a “warm body” that was willing to help. And what started as “just helping out” turned into a trial-by-fire method of learning how to run live sound and deal with all of the challenges associated with it.

Being thrust into a sometimes-chaotic moment and entrusted with delivering great sound at your church can be equal parts exhilarating and terrifying. I’ve been there! The lessons you learn in those moments can really grow your technical skills and confidence behind the mixing console.

But what are some things we can do to prepare for great sound before we have to endure the fire of a live event or worship service?

A lot of the things we learn through trial and error can be powerful lessons. But we can also form some bad habits if we don’t understand the fundamentals of audio and why something works the way it does.

3 Fundamental Concepts that Lead to Quality Sound

1. Input Signal Quality

Garbage in Garbage out! Make sure your input signal is clean, stable, and high quality. It will make the rest of your job mixing a whole lot easier!  There are two main ways to ensure a good, clean signal:

Use the right cables for your equipment on stage.

Use good mic placement to capture the best sound possible from the source (vocals / drums).

2. Setting Your Gain/Trim

This one is probably the most critical step to ensuring great sound is sent through your console and on through the other sound system components. If you have a bad gain structure, you’ll be battling the quality of your mix all day!

Gain does two things:

1. It allows you to adjust the initial signal level passing through the input preamp of the mixing console, which is then sent to all other functions of that channel and mix.

2. It provides you the opportunity to set the headroom of your audio signal so that it won’t clip, peak, or distort the console’s input electronics.

Be sure to check out this post about how to set your gain properly.

3. Understand EQ & Audio Dynamics

Getting the first two things right will go a long way in helping you achieve a better sounding mix, but you’ll be missing out on the real “sweet spot” for your sound if you don’t also address some simple EQ and signal dynamics control.

This doesn’t have to get super complicated to start with. Think of EQ as a volume control for specific frequency ranges. Knowing what ranges to turn up and down can really help liven up an instrument, give body to a vocal, or allow a mix to sound cohesive and natural.

You need to spend some time practicing with the EQ on your console and train your ears for what to listen for. There is a frequency chart that I use to help me with this.

Bonus: Download Frequency Chart

Here are a few more tips for how to use the EQ on your digital console or analog console.

Controlling some of the audio dynamics in your mix can also help clean up your sound and tighten up your mix. This is done primarily with Compression.

Compression allows you to control the dynamic range of an audio signal. This means that you can limit how loud the instrument or vocal channel can get, and you can set a compression ratio that will determine how much of the signal is compressed or “squashed”.

Here are some great tips for how to get started with compression.

Just remember, practice with these settings BEFORE applying them to your main mix. Use your rehearsal and sound check to experiment with the different features on your console.

Understanding Audio Levels

Geoff the Grey Geek http://geoffthegreygeek.com/audio-levels/

 

A basic understanding of the general audio levels mentioned in this lesson will help you avoid the common mistakes often made when connecting audio devices together. We are going to talk about three different general levels of audio signals. The names of the three general audio levels are speaker level, line level and microphone level. For simplicity, the different audio levels are described in volts. For an understanding of decibel levels used in audio, see Appendix 2 on decibels. . 

Speaker Level 

A speaker needs a few volts of electrical audio signal to make enough movement in the speaker to create a sound wave that we can hear. Small speakers need only a few volts, but large speakers need 50-100 volts to make a loud sound. 

Line Level 

A speaker is connected to an amplifier. Think of your HiFi amplifier at home. What plugs into your amplifier; DVD player, CD player, radio/tuner, video camera?  All these devices plug into the “line in” or “Aux in” of your amplifier. "Line IN", "Aux IN" and "Line OUT" all have an electrical audio signal at line level. 

You are probably aware of the standard red and white leads used in HiFi equipment, these all use line level. Other plugs are also used for line level. Line level is about half a volt to one (½ - 1) volt. It is the job of the amplifier to amplify the half to one volt of line level, up to the 10 volts or more of speaker level. 

Note: A common error is to connect plugs and sockets together just because they fit. Don't assume audio level based just on the type of plug being used. The same type of plug can be used for different purposes (and different audio levels). 

Microphone Level 

Ok, so we have line level (about ½ - 1 volt) which goes into an amplifier to make it up to speaker level (about 10 volts or above). What audio level do you think Mic level is? How much voltage do you think comes out of a microphone, as a result of you speaking into it? Answer: Stuff all! 

The output voltage of a microphone is very low. It is measured in milli-volts, that is 1/1000th of a volt. A mic can give as little as 1 mV, or up to 100mV, depending on how loud you speak into it. That is not very much. So what do you think is going to happen if you plug a mic directly into the line in of an amplifier? Answer: A very low level of muffled sound if anything. 

Mic Pre-amps 

The amplifier wants line level, ½ – 1 volt to produce enough signals to make the speaker work properly. But the mic is only producing milli-volts. So what is needed is a small microphone amplifier that amplifies the audio level from mic level to line level. This should go between the microphone and the amplifier. Because it is for the microphone and it is before the main amp, it is called a mic pre-amp. A mic pre-amp amplifies the milli-volts from a microphone up to line level. 

Mic pre-amps are normally built into devices designed for connecting to a microphone. Equipment like an audio mixer, a digital recorder, a video camera or a computer - all these may have mic level inputs as well as line level input, or just a mic level input. . 

The picture on the right shows for each input on this mixer there is a line level input (labeled Line 3 and Line 4), as well as a microphone pre-amp (labeled MIC PRE). 

Obviously a microphone plugs into the mic input, as the mic inputs are connected to the in-built mic pre-amps. 

A line level device would obviously plug into the line in socket. 

But what if your mixer (or computer/recorder) only has a microphone input, and you need to connect a line level source to it? This would result in the line level (½ - 1 volt) being connected to the input of the mic pre-amp. The trouble is, the mic preamp is expecting only a few milli-volts. The resulting sound will be much distorted as the mic pre-amp is completely overloaded. 

Attenuators 

So how can we do this? How do we connect a line level to a mic level input? We have to reduce the line level down to mic level. The technical word for this is to attenuate the signal. As an amplifier amplifies, or boosts the signal; an attenuator attenuates, or reduces the signal. 

You can buy attenuators at a music shop, they are called DI boxes. DI stands for Direct Input, Direct Injection, meaning you can directly inject a line level into the mic input without any problems. 

Audio Level Summary 

There are three main audio signal levels: mic level (millivolts), line level (around 1 volt) and speaker level (around 10 volts or more). The rule is, only plug speakers into the speaker socket of an amplifier; only line level into the line in of any equipment; and only mic level in the mic input of your mixer, camera or laptop. The most common cause of audio distortion comes from not understanding the different levels, and how to connect them all together. 

Practical Example 1 

Scenario: A keyboard (electric piano) located on the stage needs to connect to a mixer located at the back of the hall, with a microphone multi-core cable connecting between the two. 

Issue: The output of the keyboard is at line level, and the microphone input at the mixer requires mic level. (There is also the issue of different plugs and balanced/unbalanced inputs but these are the topics of other lessons). 

Solution: Use a basic DI box available from most music or electronic stores. A DI box acts as an attenuator which reduces the line level of the keyboard to mic level for direct connection to the mixer (via the multi-core cable). The DI box also overcomes the issues of matching plugs and going from unbalanced to balanced - so this is a perfect solution. This solution also works for connecting electric guitars, electronic drums and DVD players. 

Practical Example 2 

Scenario: The output (line level) of an audio mixer needs to connect to a digital camera or digital recorder which only has a microphone input. 

Issue: The output of the mixer is at line level, and the microphone input of the camera/recorder requires mic level. 

Solution: A basic DI box could be used, but this would require an input lead, and output lead and the DI box - a lot to carry in your camera bag. A neater solution is to have a lead with a 40dB attenuator built into it. This will reduce the line level from the mixer by a factor of 100, which will bring the line level down to a reasonable mic level to connect directly to the microphone socket of the camera/recorder.