Selecting a personal (IEM) system By Gino Sigismondi

Given the personal nature of "in-ear" monitoring, choosing the right system is an important step. Several choices are available. Present as well as future needs should be taken into account before making an investment.

Wireless vs. Hardwired

Personal monitor systems come in two basic varieties – wireless or hardwired. A hardwired system requires the performer be tethered to a cable, which is not necessarily a negative. Drummers and keyboard players who stay relatively stationary, or even back-up singers, can take advantage of the lower cost and greater simplicity of a hardwired personal monitor system. Simply connect the monitor sends to the inputs of the hardwired beltpack and dial up a mix. Hardwired systems also work worldwide without the hassle of finding clear frequencies or dealing with local wireless codes. Lastly, if several performers require the same mix, hardwired systems can be daisy-chained together without significant signal loss, if the input impedance is sufficiently high to allow multiple systems to be connected to a single output with Y-cables.

Figure 4: Distribution Amplifier

Another way to connect more than one hardwired system to the same output is to use a distribution amplifier (see figure 4), a device that takes a single input and splits it to multiple outputs, each with its own individual level control.

Wireless equipment, by nature, requires special considerations and attention to detail. But the advantages many times outweigh the increased cost and complexity. One of the main benefits of personal monitors is a consistent mix no matter where you stand; going wireless allows you to exploit this advantage to its fullest extent. (On their 1998 Bridges to Babylon Tour, the Rolling Stones used personal monitors on a remote stage in the middle of the seating area!) Additionally, when several performers require the same mix, hooking them up is even easier.

As many wireless receivers as necessary can monitor the same mix with no adverse effects. And of course, no cables to trip on!

CONFIGURING A PERSONAL MONITOR SYSTEM

Choosing the proper system requires a little advance planning to determine the monitoring requirements of your situation.

At the very least, you should know:
1. How many mixes your situation requires,
2. Whether you want to monitor in stereo or mono, 3
3. How many monitor mixes can be created by the mixing consoles you will be using.

This information directly relates to the equipment that you will need to satisfy the "in-ear" monitoring requirements of your band. The following example details the thought process involved in deciding how to configure your system.

1. How many mixes do I need?

The answer to this question depends on how many people are in your band, and their ability to agree upon what they want to hear in the monitors.

For example, a typical rock band instrumentation is drums, bass, guitar, keys, lead vocal, and two back up vocals provided by the guitar player and keyboardist. In a perfect world, everyone would want to listen to the same mix, so the answer to this question would be one mix. Of course this would defeat one of the main benefits of "personal" monitors, so let’s assume this isn’t the case (which isn’t too much of a stretch…).

An inexpensive configuration uses two mixes, one consisting of vocals, the other of instruments. Using a system that features dual-mono operation (dual-mono is a method of delivering two mono mixes with one stereo transmitter), the performers can individually choose how much of each mix they wish to hear (see figure 5). This scenario is a cost-effective way to get into personal monitors, yet still requires a fairly good degree of cooperation among band members. Another scenario gives the drummer a separate mix (see figure 6).

This option works well for two reasons: 1) drummers, in general, will want to hear considerably more drums in the monitors than other band members, and 2), for bands who perform on small stages the drums are so loud that they are easily heard acoustically (with no additional sound reinforcement). Therefore, drums may not even be necessary in the other mixes. So now we are up to three – the vocal mix, the instruments (minus drums), and the drummer’s mix.

Up to this point, we have assumed that the vocalists are able to agree on a mix of the vocal microphones. While forcing singers to share the same mix encourages a good vocal "blend", this theory commonly falls apart in practice (due to a phenomenon we’ll call the "more me" syndrome). Often, separating out the lead vocalist to an individual mix will address this issue, and this can be handled in one of two ways. First, place some of the backup vocal mics in the "instruments" mix, and adjust the "vocal" mix to satisfy the lead singer, even if that means adding some instruments to the "vocal" mix. We now have:

• an individual mix for the lead singer,
• a mix for the guitarist and keyboardist that includes their vocals, and
• a drum mix (at this point the bass player can drop in wherever he/she wants, often on the drummer’s mix), yet we are still only using three mixes.

The second option is to create a fourth mix for the lead singer, without affecting the other three. This configuration allows the guitarist and keyboardist to retain control between their vocals and instruments, while giving the lead singer a completely customized mix. Does the bass player need a separate mix? Now you are up to five mixes. Adding a horn section? That could easily be a sixth mix. So where does it end? Well, several other factors (including your budget!) will help decide at which point you limit the number of mixes.

2. Do I want to monitor in stereo or mono?

Most personal monitor systems allow for monitoring in either stereo or mono. At first glance, stereo may seem the obvious choice, since we hear in stereo, and everything else these days features stereo sound - CDs, TV, VCRs, even your computer. Stereo, by its very nature, requires two channels of audio. What this means for personal monitor users is two sends from the mixer to create a stereo monitor mix – twice as many as it takes to do a mono mix (see figure 7). Stereo monitoring can rapidly devour auxiliary sends; if your mixer only has four sends, you can only create two stereo mixes, versus four mono.

While not quite as "realistic" as stereo monitoring, mono allows more mixes from a smaller mixing console, and sometimes fewer transmitters. Some stereo transmitters can be operated in a "dual-mono" mode, which provides two mono mixes instead of one stereo. This capability can be a great way to save money. If you only need one mono mix, or if you are a solo artist or jobbing musician looking to have your own personal system, mono-only systems are another cost-effective option. Strongly consider a system that includes a microphone input that will allow you to connect your primary instrument directly to the monitor system.

3.How many mixes are available from the front of house console?

Monitor mixes are typically created using auxiliary (Aux) sends from a mixer, either the front-of-house (audience) console, or a dedicated monitor console if it’s available. A typical small-format console will have at least four auxiliary sends. Whether or not all these are all available for monitors is another matter. Aux sends are also used for effects (reverb, delay, etc.). At any rate, available auxiliary sends are the final determinate for the number of possible monitor mixes. If your answer to question 1 is greater than the answer to question number 3, you have two options: reconfigure your monitor mixes to accommodate the mixer, or get a new mixer. Keep in mind that if you don’t have a mixer and rely on the equipment supplied by the venues where you play, be prepared to deal with the number of monitor mixes they are equipped to provide.

4. How many components will I need?

After you have answered the above questions, plug the numbers into the following equations to determine exactly how many of each component you will need, and choose a system that can handle these requirements.

STEREO:
Number of transmitters = number of desired mixes
Number of aux sends = 2 (number of transmitters)

(e.g. 4 mixes requires 4 transmitters and 8 aux sends)

DUAL MONO:
Number of transmitters = number of desired mixes/2
Number of required aux sends = 2(number of transmitters)

(e.g. 4 mixes requires 2 transmitters and 4 aux sends)

MONO ONLY:
Number of transmitters = number of desired mixes
Number of aux sends = number of transmitters

(e.g. 4 mixes requires 4 transmitters and 4 aux sends)

Number of receivers = number of performers

The scenario described above is only one of many ways in which a personal monitor system can be implemented. The configurable nature of the systems allow you to build a system to suit your specific needs. Expandibility, one of the key benfits to personal monitors, allows the system to grow with your needs. Communicate with others who already use them to see what they have done, or contact the manufacturer for help with configuration or selecting the best system for your application.

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Gino Sigismondi work in the Applications Engineering department at Shure. He is also the author of Shure's "Guide to Personal Monitors" available at:
http://www.shure.com/booklets/techpubs.html.

(c) 2003 Shure Incorporated. Used by permission.