Choir Tech Know-How: Part 2

In my previous article, Choir Tech Know-How: Part 1, I gave you an overview of the different parts making up a sound system and different types of sound systems you can use for your choir. In this article I am now going to delve a little deeper, looking at the music player, amplifier and mixer and what they do.

Music Player

To play backing or rehearsal tracks for your choir, you could simply use an Mp3 player or CD plugged into a speaker system. This will work fine, but has some drawbacks, particularly for rehearsals. Mp3 players are designed to play one complete track after another. That’s great on the train, but when you’re learning a song, it’s less effective. Not being able to easily go back to a particular point in the music is frustrating. Listening to a 16-bar introduction every time you want to play part of the track is a waste of your time and will quickly get boring for your choir. Larger tablets are better for this as they often allow you to drag the play bar back to roughly the right position, but it can be tricky to do accurately and you can’t mark positions on the tracks.  My preferred solution is using a DAW (digital audio workstation) program on a laptop.

A DAW is a program designed to record, edit and play back music. I use it because it allows me to mark various places in a track, play different choir parts from a particular point, and generally see what is happening in the music. I will explain in further detail how I use the DAW in a dedicated article. The important point to note is that you will need to play the same track many times, often starting in different places, while you are learning your songs and this is a speedy and effective method.

Amplifier/Mixer

The amplifier/mixer part of the equipment comes in many forms. It can either be one item or two or more separate items. Put simply, the amplifier boosts the signal coming in from the music player so that it is strong enough to be used by a speaker. The mixer allows you to have more than one audio source entering the amplifier at one time. How these two interact is often the biggest cause of confusion.

You will need a mixer if you want to have more than one source of audio playing through your speakers.  These sources could be a backing track, microphones or instruments.  All good mixers allow you to mix two or more signals and balance (ie change the relative levels) of each audio source. This is important in order to get a good blend of sound.

Mixers come in all shapes and sizes. You do not need a complicated mixer for rehearsals.  You just need to ensure that you have enough channels (one for each sound source coming into the mixer) for your particular set up.  At Total Voice Contemporary Choir, we use one stereo input for backing tracks and between one and four channels for microphones, depending on whether there are soloists or not. Each channel should have input level gain control (which allows you to balance the strength of the signals coming to the desk), some EQ, and channel faders to control the volume of each sound source. The desk should also have a master volume. On small desks these volume adjusters are often rotary knobs, on larger desks they are likely to be sliders – I find sliders are easier to work with as they show you the relative volumes more explicitly. It is important that the desk has enough outputs to allow you to attach the various speakers you want to use.

Other features that are nice to have include left and right pan options on the channels, auxiliary channels (that allow you to have more than one mix of the sound) and mutes on each channel (so you can cut off the microphones when necessary).  Solo buttons (that cause just the selected channel to be sent to the headphone socket), and a headphone socket (so whoever is operating can hear what is happening on each channel) are also very handy.  All this sounds a lot but most of it is found on even the smallest general purpose mixer.

In portable combination systems, the mixer can be part of the speaker. Each input will generally have its own gain adjustment (“gain” is how strong the signal is) and an overall volume (how loud the speaker is).  It is important to get these two clear in your mind when you are trying to solve problems, but more of that later. In these systems you never actually see the amplifier as it is built-in to the whole system. For larger multi-speaker systems, it is normal to have a separate mixing desk and amplifier. There are two main types – a passive desk and active speakers, or an active (or powered) desk and passive speakers. Each system has its advantages and disadvantages.

Passive desk, active speakers – here the sound goes into the mixing desk where it is combined before passing along cables to one or more speakers which each have an amplifier in them. Each speaker will have its own volume control and sometimes will have the ability to act as simple mixers as well. Our main speaker can, for example, take the audio signal from an mp3 player and a single microphone. The advantage of this system is that each amplifier is separate; if you blow an amp outdoors on a wet day, you can continue with the other speaker. The desk is lightweight, but the speakers are heavy and require mains power.

Active desk, passive speakers – here the sound signals go into the desk where they are either amplified in the desk itself, or are amplified in a standalone amplifier before passing down special cables to your speakers. In general, these speakers do not have volume adjustment on them as this is done from the amplifier. In this case, if an amplifier blows you will lose all sound. The advantage is that the speakers are light and do not need mains power so are more portable. The desk and amplifier are heavier though, and you need to understand how to match your amplifier to your speakers for both watts and ohms.

Speakers

When it comes speakers, size matters. Speaker sizes are measured in watts rather than physical dimensions. What does that mean for us? Watts correlate with how much sound the speaker can make – bigger wattage speakers generally make more noise. For rehearsals, you do not need massive speaker systems. We rehearse a choir of sixty with a single 150W foldback speaker and we have plenty of volume in hand should we need it. So somewhere in the 1 -2 watts per person is fine. For a gig, you hopefully will have more people in the audience than the choir – so you will need more powerful speakers.

As a very rough rule of thumb for indoor performance, you can get away with about 5W per person in the audience, ie a 150 seat hall would need about 750W of power.  If you need to amplify in an outdoor venue you need to approximately double the amount of power per person, so an outdoor venue for 150 would need closer to 1500 watts of speakers. These are obviously very rough figures and depend on whether you are going to amplify the singers or not. If you are not amplifying your singers then you need to match the backing track volume to what they can produce. There is no point having a 1000W of speakers pumping out a backing track if you have a unamplified choir of twenty.

I hope you found this article helpful. Next time I will be focusing on microphones.  I will also be putting together some video posts on desk set up and management.  In the meantime do send in your comments and queries and I will be happy to help.

Comments on Choir Tech Know-How: Part 2

  1. Avatar Richard Seaby says:

    Hi Tony

    I hope you have fun singing to backing tracks, it allows you to do some very different types of songs. A couple of things to consider. Are you going to have to setup and take down every time – if you are then lightweight gear is worth the extra money! And second, if you are going to mix backing track songs with accompanied songs, you have to be careful not to make the backing track songs too loud if you intend to return to other acoustic songs as they can sound rather thin and empty in comparison.

    The basic requirement you have in terms of kit sound fine – 2 main speakers, desk and mp3 input of some kind are all essential.

    As for monitors, I would think a single monitor would be plenty. In small indoor venues, the distance and position of the main speakers usually means that the choir can hear the tracks okay anyway without a monitor, so you could save some money and some lugging of kit there.

    As for main speakers, if you do not intend ever to mic your choir, I think that you will never need 1000W of power. Don’t get me wrong, it is always nice to have the power available, but there is a cost, both in money terms and in bulk and weight terms. If you intend to mic the choir at some time in the future then you might need that sort of power, especially if you perform outside. We have two 600W Behringer Eurolive Speakers, which to be honest we have hardly ever used, and intend to sell and change over sometime to a pair of 400W. They sound great, but are very heavy and way over specced for most of our gigs. I have done several gigs with 2 x 200W speakers for audiences of 100 or so, outside, and the sound has been okay.

    Adding mics to the choir can be complex. However, for quick setups, I have found 3 Rode M3 mics in front of the choir enough to add appreciably to the sound without highlighting any particular voice. If you get this type of mic, a desk that can run phantom power is good.

    I suggest that you need good stands for your main speakers – you get much better sound when they are raised, ideally above the head height of the audience.

    I hope that helps
    Richard

  2. Avatar Tony says:

    Hi Richard,
    We have a mixed SATB choir of around 80 voices and have started to introduce backing tracks into some of our more modern pieces we sing. However the PA system and requirements are causing some indigestion as you can imagine. There is a strong feeling that we need to have a system that comprises, 2 speakers, mixing desk / amplifier, cd/mp3 player and a couple of monitors. with a power output of around 1000W.
    We do not mic up the choir and when we perform it is usually indoors to an audience of around 150-200 people. Any advice or suggestions of what kit to purchase would be very welcome.
    Thanks in advance
    Tony

  3. Avatar Sara says:

    Richard,

    Thanks for the really informative article, I too am after some tech advice. We are a choir of 50 ish and perform with backing tracks (cd/mp3) but also with keyboard. Our events have often been outdoors, but didn’t know if there was some sort of system that might be flexible enough to cope with indoors as well?

    We have no mics, speakers or anything and to be honest, very little knowledge. So it would need to be fairly idiot -proof and quick to set up. Am I asking too much?!

    Have no idea what this sort of spec requires in terms of budget, and for the number of performances we do, it wouldn’t be worth investing too much. Still, anything up to £500 sounds about reasonable?

    Very grateful for your expertise,
    Sara

    1. Avatar Richard Seaby says:

      Hi Sara. Firstly, I’m sorry I haven’t replied to your comment sooner.

      I’d love to be able to tell you that you could get everything you need for £500, but I’m afraid you are asking rather a lot! You can either go for a basic, indoor rehearsal set-up (see my reply to Michaela), which you could probably afford to buy brand new, or you can go for a more sophisticated rig, but secondhand. You might well find that you can buy a complete set-up on eBay, but you will need a bit of savvy to buy secondhand. Fortunately, I will be covering secondhand equipment in an article in the near future, so watch this space!

    2. Avatar Michaela Sesay says:

      Thanks for your advice above. We were given the same advice ( re:the Yamaha) by another independent sound engineer too. We have been very fortunate in acquiring an excellent (hardly used) Yamaha Stagepas 300. It is rather heavy in the custom made double bag so we are now looking at getting two single bags to make it a little easier to transport.

      Thanks again

      Michaela Sesay
      (On behalf of Harmony http://www.harmonykent.com)

  4. Avatar Richard Seaby says:

    Hi Michaela

    Thanks for your question.

    For the sort of money you want to spend (£500), the easiest option is to stick to a bundle that is guaranteed to work nicely together. You can get something like the Yamaha Stagepas 400i PA System – a good reasonable quality system that is pretty flexible. This is and 8 channel + usb in set up, so is pretty flexible. It weighs in at about 20Kg according to the specs on line. Its speakers also function as floor fold back if you need them to – this can be handy at some places which have good main speakers, but nothing to play the music back to the choir.

    If that is a bit pricey then you can get something like the Behringer Europort EPA300 Portable 300W PA System – obviously a step down in power and some would say build quality, but I have used lots of Berhinger stuff and if treated well it is pretty good. This has 6 channels + a cd in, which should be plenty unless you want to mic everybody separately. These speakers would not work well as floor fold back by the look of them. You would also need to check that they can go on speaker stands – it is very important to get the speakers in the air, if you want the sound to carry across an audience.

    If you know you will only ever need the backing track and an announcer mic and keyboard they you could go something like the Mackie Thump TH-15A (Pair) PA System – these a great speakers, but the little mixer that comes with it is quite limited. It can handle a couple if inputs plus a cd.

    The other option is to go for separate parts. A long as you know whether you are buying a passive or active speakers and you get the appropriate mixer/amplifier then the should work together – however the nice thing about the bundles is they tend to be good value and someone else has done the thinking for you.

    The other factor to consider is if you need to invest in other bits that go with the system such as mics, mic stands, extension leads, cables. This can add up quite quickly, but you may already have quite a lot of the kit.

    If it was my money, I would be tempted by the Yamaha – the extra couple of channels, speaker that can act as main and fold back, and the good reputation of Yamaha for equipment. As ever – if you can get somewhere to try our some of these systems then that would be best!

    Good luck and if you have any other questions, let me know.

    Richard

  5. Avatar Michaela says:

    Hi

    Thanks for this choir specific advice. We are a choir of 9 and sometimes we perform using backing tracks (iPod) and sometimes using a pianist on a keyboard. We are looking for a portable PA type system that will work for both. Our biggest audience size in a non sound engineered venue is approx 140. Would you recommend anything in particular please ? Our budget is approx £500.

    Thanks
    Michaela
    (On behalf of Harmony http://www.harmonykent.com )

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