Alesis MONITORI User Manual

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Monitor One

Reference Manual







A LITTLE HISTORY ...............................................





SPEAKER PLACEMENT........................................



CONNECTIONS ....................................................



POWER AND PROTECTION ..................................






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3.0A Architectural and Engineering Specifications...........




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3.1A Cleaning...........................................................................



3.1B Service .............................................................................




Your new Alesis Monitor One™ Studio Reference Monitors will deliver accurate mixes in near-fielddigital and analog studio monitoring applications. The Monitor Ones offer wide frequency response, accurate transient reproduction, clear imaging and high power handling capability and were designed by experts with decades of experience in professional loudspeaker design.

This speaker system uses a proprietary 6.5" high-powerlow frequency driver with a specialmineral-filledpolypropylene cone, a highly damped linear rubber surround and a 1.5" diameter voice coil wound on ahigh-temperatureKapton former. The 1" high frequency driver employed has a soft natural silk dome and is ferrofluid cooled. The system's crossover network uses low dielectric lossnon-polarizedcapacitors and an oversizedlow-losslow frequency inductor. Rear panel connections are made via 5- way binding posts suited to large diameter wires as well as banana plugs.

The cabinet design uses Alesis' exclusive SuperPort™ speaker venting technology. Most small speakers used for near-fieldmonitoring give disappointing results in their lowest frequency range. They are either sealed (which limits the amount of air the driver can move) or have an undersized vent whose function at low frequencies and high acoustic output is nullified by the effect of turbulence in the restricted port tube. The Monitor One's large folded SuperPort overcomes this limitation by minimizing vent turbulence at high air velocities, thereby ensuring that the enclosure tuning remains stable, the acoustic output remains linear during heavy low frequency attack transients, and that the reactive load above and below box resonance seen by the driving amplifier does not dynamically shift in frequency. This all translates to tighter bass with higher definition.

The Monitor One's 4 ohm load impedance takes advantage of today's modern professional amplifiers which are generally capable of a 1-3dB increase in output power with 4 ohm loads over their 8 ohm ratings. The result is a similar increase in the Monitor One's acoustic output over conventional 8 ohm monitors.

Reliable handling of this additional acoustic output is ensured by the Monitor One's substantial power handling capability. Typical near-fieldmonitors are rated at50-60watts maximum whereas the Monitor One carries a 120 watt continuous power rating and has


been successfully tested to over 200 watts using the industry standard EIA-426Amethod. This a rugged speaker system designed for serious professional use.

Covered with a non-sliprubber textured laminate for stable mounting, the Monitor Ones come in a mirror image left/right pair for symmetrical horizontal mounting.


In the early days of recording, most recording studios used big monitor speakers almost exclusively. Unfortunately, they also required high powered amplifiers and expensive acoustic treatment (often poorly done) of the entire control room. Still, awell-constructedbig monitoring system really was impressive to listen to, a fact not overlooked by the studio owners who wanted to impress the record company executives who paid for the big studio's time. These big systems had big level control knobs, and clients enjoyed"cranking-up"the volume.

Fortunately, recording engineers and producers eventually learned that this was not the best way to accurately mix music

because it wasn't the way people listened to their radios, cassettes and CD players (metalheads excepted). Also, big monitor systems and the costs for the required control room acoustic treatments were going through the roof (no pun intended), particularly beyond the budget limits of smaller project and home studios which were growing in numbers. A new way of accurate monitoring was needed: near-fieldmonitoring.

Near-fieldmonitors, by their definition, are intended for mounting close to the listener. The idea here is to improve the direct acoustic path between the speaker and the listener by making it shorter, thereby giving less opportunity for the always present indirect (reflected) sounds to get back in and muddle things up. Withnear-fieldmonitoring, the surrounding acoustic environment becomes a much less significant factor in establishing the monitor system's sound character.

A good set of small monitors properly placed in a reasonably non-reverberantroom and powered by a100-wattamplifier will yield surprisingly accurate results at budget prices. Carried to another studio, the same monitor should also providerepeatable results. In fact, some recording engineers carry their own speakers around because they know how they will sound in almost any room. Now, even the big studios use smaller speakers


to augment their big monitoring systems, and near-fieldmonitors have become proven tools in the recording business.



Like any speaker system, your Monitor Ones will work best when properly positioned in a suitable acoustic environment.

Achieving proper speaker placement is usually straightforward, but even with near-fieldmonitors, speaker placement and the acoustics of the listening room itself are too often overlooked and can become significant contributors to an inaccurate and uninspiring monitoring environment.

Please take a moment to read this information carefully. It will help you to get the most use and enjoyment from your new Alesis monitors.


While near-fieldmonitors are more forgiving of the

surrounding room acoustics, it is always prudent to optimize the listening environment whenever possible. First, the user should be aware of the effect that the size of the listening room can have on low frequency response. In general, the smaller the room, the stronger the bottom end will be, although placement within a larger room can also make a difference. This has to do with the way low-frequencywaves travel in closed spaces. If you find your monitor system to be either light or heavy on the bottom, try moving them around within your listening room. Also, because the Monitor One's SuperPort tube is located at the rear, position the monitors at least six inches away from anything that would block it.

You should avoid locating your Monitor Ones near reflective surfaces such as glass, tile, large open walls or table tops. Still, many rooms used for recording have these surfaces, so the best way to deal with them is to place the monitors out in the room away from reflective walls, windows and sizable objects.

Even with these reflective surfaces separated from the monitoring position, typical mixing situations usually still have the top surface of the mixing board to deal with. Unfortunately, the

board itself can be a major source of reflections and the additional acoustic conduction into the board can affect your monitor's amplitude and phase response. Speaker placement on the console's meter bridge provides for two clear acoustic paths between the speakers and the recording engineer which results in undesirable comb filtering effects and poor imaging. The first path is the direct one, and the second is via a reflection off the mixer main


control panel (as shown in Figure 1 below). This kind of speaker placement also couples acoustic energy from the speaker's cabinet more readily into the console's chassis. Both conditions should be reduced by placing the speakers on their own stands acoustically detached from, and slightly behind, the console as shown in Figure

2. In this location, the reflective path off the console's control panel is now blocked by the meter bridge.

Figure 1

Direct Path


Monitors placed on the console’s meter bridge can directly radiate back onto the console control panel causing a strong delayed reflection at the listening position

Figure 2







Direct Path





































































































































































Moving the monitors to a position behind the meter bridge causes the bridge to block the offending reflective path

Careful consideration should also be given to the physical spacing between the speakers. Alesis recommends that the distance between the speakers equal the distance between the listener and either speaker. In other words, the listener and the two speakers are at the three corners of a triangle having equallength sides. Figure 3 shows this concept. Note that both speakers are turned in somewhat, so that the prime listening position is directly out in front of each speaker. Applications that require monitoring by


more than one engineer are accommodated by a smaller rotation of the cabinets. This will widen the prime listening position somewhat.

Figure 3







The speakers and listener should be at the three corners of a triangle having equal length sides

Prime Listening Position

Alesis has designed the Monitor Ones for horizontal mounting. This keeps their height profile as low as possible to minimize the recording engineer's visual obstructions. Your Monitor Ones are supplied as a symmetrical left-rightpair, and if used this way, should be installed with the soft dome high frequency drivers towards the outsides of the triangle. The high frequency driver should be on the left side of the left monitor and on the right side of the right monitor (see Figure 4 below). Of course, the traditional method of mounting the speakers with the high frequency drivers at the top is perfectly acceptable too.

Figure 4


The high frequency driver should be on the left side

of the left monitor and on the right side of the right monitor


The Monitor Ones are completely covered with a non-sliprubber textured laminate whereas other speakers provide smallstick-onpads (or nothing at all) to keep them from slipping around while they are playing. If you need to move the Monitor Ones or adjust their position slightly, lift them off the mounting surface first rather than attempting to slide them.


Professional grade 5-waybinding posts are provided for external wiring to the amplifier. This type of connector can accommodate bare or tinned wires, banana plugs and even spade lugs.

About Wire: A lot of hype and confusion exists about the type of speaker wires to use, most of it created by the wire manufacturers themselves in an effort to have a unique story to tell. While this expensive wire will not hurt the speaker's performance at all, Alesis does not subscribe to most of this hype and chooses to take an approach based on science when recommending speaker wire. Our recommendation is simple; use the shortest length of the largest diameter wire you can get.#12-14gaugemulti-strandedspeaker wire found at mosthi-fistores works very well. This kind of wire resembles oversized lamp cord and is very easy to work with.

Before connecting the speakers, make sure your amplifier is turned OFF before making connections to it. Be sure you get the + terminals of the speakers wired to the + terminals of the amplifier.

To help you do this, most speaker cable has a way to tell one conductor from another. Some use different-coloredwires or insulation; others mold a small line or marker into one insulator to mark it. If one speaker's polarity is out of phase with the other, the result will be loss of low frequency response and stereo imaging when the system is played.

In most cases, the speaker outputs of the amplifier will have a red terminal and a black terminal; these should be connected to the same-coloredterminals of the Monitor One. Consult the manual of your power amplifier for specific information. In aproperly-phasedsystem, a positive input to the amplifier should

result in a positive voltage on the red terminal, and push the driver forward.

If you are using a dual banana plug connector, one side of



plug usually has a "GND" marker molded on it so you can keep polarity straight after unplugging and replugging. In standard practice, the GND side connects to the black terminal of the speaker.

To connect wires to the terminals if you are not using a banana plug:

1.Strip about 1/2" (15 mm) of insulation from the ends

of each wire. If the wire is stranded, twist the strands together at the end.

2.Turn the red and black terminal caps counter-clockwiseuntil they reach their limit. As you do, the hole through the terminal post will be exposed.

3.Insert the wires into the holes, observing proper polarity.

4.Tighten the terminal caps so that they hold the wire firmly. Make sure no insulation is caught inside the terminal, to avoid a loose connection.


Alesis recognizes that professional speakers need to be strong to survive, so the Monitor One is designed to handle twice the power of other near-fieldmonitors. This was achieved by using proprietary high power drivers and oversized crossover components, choices made principally to offer the user an extended margin of safety. Therefore, an amplifier with a

100 watt power rating into 4 ohms, like the Alesis RA-100™

Reference Amplifier, is recommend for most monitoring situations. Higher or lower power amplifiers may be used, depending on the size of the listening room and the engineer's preference for normal working levels.

Be sure to verify that your amplifier is rated for 4 ohm speakers.

Some older amplifiers are not and may fail if overloaded. Alesis is not responsible for any failures caused by the use of an inproperly-ratedamplifier.

Also, there is no situation where an amplifier rated beyond 200 watts should ever be used because of the danger of damaging the Monitor One. To do so is asking for trouble and will void your warranty. On the other hand, if you use too small of a power amplifier, it is possible to damage the Monitor One if you run it into heavy clipping and distortion in an effort to get sufficient volume.

This can lead to failures of both the amplifier and the speaker, as