Introduction To Equipment Components By: Keith Ling

April 8, 2008 by Mobile Beat Staff Writer

I. Basic FactorsChoosing equipment may well be one of the most excruciating decisions for the new mobile DJ. You wonder if it will last, whether you might be missing something better, or if you’ll end up spending more than you can actually afford. Chill your anxiety with a little planning before purchasing. Just because a deal looks good doesn’t mean it is good. There are four basic factors you should consider before purchasing. The first determining factor is not money, but rather your customer market.

A. Customer Market

Before jumping into the sometimes perilous surf of mobile DJing, you should test them. First of all, are there successful DJs in your geographic area? If not, determine why. Many small towns simply do not generate enough parties to support a mobile DJ. If you just want to start part time, this may deal with that problem. Be aware that most DJs have other jobs in addition to their weekend work. That does not mean you can’t make a living at it, it just means you have to be successful and in a market sufficient to generate the business that will be required to generate a sufficient income.

Most DJs work a wide variety of parties. Some specialize in weddings, but they usually will do a private party or school dance if they have a last minute call for a date that was not booked. All this to say- don’t expect to play only the music you like. You must be willing to play a wide variety of music to get a wide variety of customers. You will need a lot of customers to generate the income required to pay for the equipment you need and/or want.

For the mobile DJ, there are several basic markets. In regard to size of your system, there are basically three. These include small parties (under 100 people), medium size parties (100 – 300 people), and large parties (generally 300-1200 people). Most mobile DJs will commonly handle small and medium size parties, with the occasional large show. Your equipment should be able to handle the medium size party with little problem. You can often rent extra equipment to handle larger parties.

B. Budget

Your budget will also limit how much you spend on your equipment. You may have to forego that 1200.00 dual CD player with seamless looping. Many DJs start with home CD players a basic mixer, a pro amplifier and some decent pro speakers. The term “pro” refers to equipment normally intended for heavy-duty use including bands, large public address systems, and dance clubs. Home stereo amplifiers and speakers do not generate enough power to drive large speaker systems to high volume levels in a large room. They are also not durable enough to handle these volumes for 3-5 hours at a time. Durability is also an important factor when you are carrying home stereo amplifiers and speakers over the road. Home stereo equipment is simply not designed for this application, and will eventually fail due to the punishment that they will receive when used in this manner.

Because of this, it is best to place the highest priority of your budget on speakers and an amplifier. Cheap speakers and a poor amplifier will only cause heartache in a very short time. Pushing a cheap amplifier excessively will damage the best speakers, and the cheaper speakers will fry even faster. Realistically (and no, I’m not referring to brand names here!), you can expect to pay anywhere between 500.00 and 1200.00 for a quality pro amp, and 600.00-1200.00 for a pair of quality speakers. That does not include stands, cases, and cables! Concentrate first on what will help you sound great, then you may want to go after the bells and whistles.

C. Transportation Options

A local band is breaking up and is selling their system at pennies on the dollar. Your techie friend tells you the stuff is in great shape and is a steal. Should you jump on it? Maybe – if you can get it home. Keep in mind that you will be moving your equipment to and from every show. Do you really want speakers that weigh 95 lbs. each? Even more important is what vehicle will you use to get to and from shows? It won’t be easy to fit a lot of bulky equipment in a hatchback. If you already have a mini-van, sport utility vehicle, or a cargo van, you have a little more flexibility.

Do your back a big favor- buy a heavy-duty hand truck. You may be able to get by with a 30.00 convertible truck at first. These are not ideal, but they’re much better than carrying each item in by hand. Many DJs use the “Rock and Roller” carts. I use the largest model, the RR-10. It has saved me a lot of time and backaches, and has been well worth the 170.00 I paid for it. It holds my entire basic system plus CDs and mini-discs! It expands from 2′ to 4′ and has a 500 lb. Capacity. Whatever cart you choose, make sure it can handle the load without tipping!

D. Personal Preferences

While the first three factors require logical consideration, your preferences don’t. We often buy things because they look cool, or they have a more “quality feel”. There is nothing wrong with these preferences. They often lead to a “best decision”- but often after the three preceding factors have been considered. Make sure you try out your purchase before buying if that is possible. If you don’t like it, don’t hesitate to return it if your dealer allows returns. Be comfortable with your equipment- it will either help you or hinder you.

II. Sound Equipment Selection

Your DJ system must have A) MEDIA B) MEDIA Player C) Mixer D) Amplifier E) Speakers F) Connections. A quality DJ system will also have microphones and processors. This section is designed to show how these components work independently and as part of a total system. We will also present some examples of differing designs of each chain of the DJ system.

A. Media

Simply put, media is the format of the music you will be presenting. The most common media used by DJs are compact discs, vinyl records, mini-discs, and cassette tapes. Computer generated media is growing in usage, but is currently not practical for most beginning DJs. Superior CD recorders and mini-disc recorders are quickly replacing cassette tapes. Vinyl is still a strong niche market for DJs, but the styles of music available are primarily limited to rap and club music. Compact discs are still the overwhelming media of choice for the mobile DJ. The largest variety of new music is readily available on compact disc. Mini-discs offer the DJ the option of producing pre-mixed music, special “style discs” (like current ballads, line dance country, party classics, etc.) and vocal drops or pre-recorded announcements. CD recorders offer the same convenience with the exception of some editing features and ease of use. You should understand that it is illegal to make recordings for DJ applications! Whichever media you choose, make sure it allows you to easily please your customers.

B. Media Players

Media players do more than simply play music. They help you present it with your style. Mobile DJs should look for players with a quality feel as well as performance. Some CD players have features that make this much easier. First of all, a dual CD player offers the convenience of having the controls close to your mixer. Instead of bending over to look at your controls, you simply glance down at your angled mixer rack. Some players offer exceptionally fast cueing (setting the song to the beginning before starting) and start-up (how fast the music comes on when you press “play”). Some newer models have “skip chips”, that is, circuit boards that prevents your music from skipping when someone stomps near your player. For the perfectionist, there are players with “seamless looping” that allow you to mix from one song into another without missing a beat. Finally, there are players that remember specific songs and will cue them automatically to “hot buttons”. There are other advanced features available on CD players as well as mini-disc players, but these are the ones most preferred by DJs. They are also the features most DJs ask for when new media players are presented to them

The number of media players that you carry is also an issue. Quite routinely, newer DJ’s will carry only two CD players to each event that they perform. If one of them malfunctions, and you are left with only one operational CD player, you have a major problem on your hands. Carrying only two CD players (or just one dual CD player) is a disservice to your client, and to your reputation. Generally, you should have at least three CD players if that is your main format.

C. Mixers

Mixers do just that. They take a variety of media, mix them together, and send that signal to your amplifier. They receive signals through inputs and send them out through outputs. A typical mixer can handle two turntables, two CD players, a microphone, and a mini-disc player or extra CD player. Most DJ style mixers have output “channels”. The most common are 2, 3, and 4 channel models. Each channel typically has two possible source inputs to it that are controlled by a selector switch. A mixer with four channels may cost more than a three-channel unit, but it will also give you greater performance flexibility.

Determine your needs with the idea that you may add on later. Make sure you are comfortable with the fader action. Assignable crossfaders may make mixing easier, but they can become a source of mistakes also. Sound effects may be fun, but how often will you really use them? Samplers are another toy in this category. You need to be serious about using them if you want to truly justify your purchase. Equalizers can be helpful, especially when starting out. Use them wisely and sparingly. I highly recommend models with two microphone inputs. You don’t need to worry about switching cables if one mic goes out and you have a back up plugged in.

Another good feature to look for on your mixer, is a separate bass and treble control for the microphone. This allows you greater flexibility in adjusting the proper sound for the mic as well as the music.

An audio mixer consists of five parts:

· A mixer

· A pre-amplifier

· A cueing system

· An equalizer system (optional on some mixers)

· A meter system

The mixer section is the mechanism that allows you to gradually fade from one song to another. There are individual volume controls that allow you to increase or decrease the volume to each component, such as a CD or tape player, the microphone, etc. There is a main “Master” volume control that control all of the components hooked to the mixer. It does not matter how high an individual volume control to a CD player is set, if the Master control is at the lowest position, you will not get any sound out of the mixer! The Master volume control should be set at approximately 1/2 volume at to start.

The pre-amplifier system is the portion of the mixer that is used for turntables or phono inputs. This is necessary because the raw sound produced by a turntable is very low compared to CD players or tape decks. By comparison, the signal produced by a CD player or tape deck is much higher. The pre-amplifier system boosts, or amplifies the very low signal from the phono cartridge so that it matches the higher output signal of a CD player or tape deck. Most mobile DJ’s do not use turntables. The one thing you need to remember is that you cannot plug a CD player or tape deck into a “phono input”. If you do, you will get a very distorted sound.

The Cueing system on a mixer is designed to allow you to listen to a song through a headset from one CD player, while a song is playing from a different CD player through the speakers. Typically, while people are dancing to one song, you get your next song ready, and preview the song through the headset. There is a separate volume control for the headset.

The equalizer on the mixing board is designed to allow you to adjust the bass, treble and midrange sounds of the system.

The meter system of the mixer is important to the disc jockey. The “VU” meters on the mixer tell the disc jockey if he is overloading the amplifier. Specifically, the level on the VU meter tells you how “clean” the signal is going into the amplifier. When the VU meter is constantly in the red, this indicates a distorted signal, and will eventually result in a blown speaker, overheated amplifier or both. These meters can also be used as a troubleshooting tool when determining if there is a problem with one of the components or the mixer itself. There are two sides of the meter, one left channel, and one right channel. In the event that the meter is only displaying output from one channel, you will most certainly have sound from only one speaker (assuming you are using the stereo mode). In this situation, it usually means that the mixer is receiving sound from only one channel of the CD player/tape deck.

A good mixer will often last longer than most of your system. My first mixer was five years old when I bought it, and I enjoyed it thoroughly for three more years. Make sure you try before you buy. This is the one piece of equipment you will touch a lot. Be comfortable- and keep it clean!

D. Amplifiers

Amplifiers are the “muscle” of your system. They take the signals delivered from your mixer and convert them into electrical power sufficient enough to drive your speakers at volumes exceeding 120 decibels! This is one of the two most important items in your system. A great amplifier will let you deliver more-than-sufficient volume with very little strain. For the medium-sized parties mentioned earlier, you will need at least 200 watts per channel at 8 ohms with a distortion rating below 1%. Keep in mind that the more you run your amp at full output, the greater the wear and tear due to heat. Many DJs start with 300+ watts per channel.

Most amplifiers have at least two inputs – one for each channel or speaker (left and right channels). They also have two to four outputs that go to the speakers. Typically, you will find two different types of outputs on most amplifiers. The first type, is the “banana plug”. You can find this on the back of your amp by finding the red and black posts that stick out of the amp. There should be at least one pair of “banana plug” speaker outputs per channel. The other type of speaker output is the ¼” female output. You can easily locate the speaker outputs by locating the black and red banana plug terminals. The ¼” speaker output is generally located adjacent to the banana plug outputs.

In the event that the amp gets overheated, the possibility of the amp blowing a fuse or tripping a built in “shut-down” circuit breaker may occur. Most amplifiers have a built-in shut down breaker that shuts down the amp because it has overheated. The amp can be used after it has cooled down (usually 15 minutes). If the amp shuts down, before continuing, you should find out why it overheated to begin with. The usual cause of an amp overheating and shutting down is due to trying to play too loud to the point that you play a distorted signal. While it is important to know about the possibility of the amplifier shutting down due to being overheated, you should know that there is an extremely small chance of this actually happening, provided that you are using brand name, professional amplifiers.

You can expect to pay between 500.00 to 1200.00 for an amp rated 300-400 wpc. This may seem like a “budget buster” at first, but a quality amp can last 10 years or more, if you take care of it. Check the warranty when you buy – some are better than others. The best warranties are typically 3-5 years and are “no fault”. That means that repairs will be covered for anything short of obvious abuse (I.E., mangled casing, soda stains on circuit board, etc). Make sure your amp can be serviced locally. Next Day Air shipping can be expensive on a heavy amplifier. Buy quality and minimize repair hassles.

E. Speakers

Quite simply, speakers are the most important link in your sound system. Amplifiers, CD players, and mixers do not produce sound. Speakers produce sound when signals of sufficient amplitude are fed to them. Much can be said about electronic measurements of speakers, but these measurements rarely tell you what your ears hear. Speakers are the one component that you should strongly consider purchasing from a local dealer. The only way to truly judge a speaker is to listen to it. Be sure to listen to a wide variety of music at a variety of volume levels. Walk around the room and notice any changes, especially in high-end instruments and voice. Keep in mind that while a speaker may seem to have a stronger high end, it may cause “listener’s fatigue” at loud levels over several hours. Also note the “throw” of the system- that is, how far the sound will carry and cover an area. Some systems have a great throw, but may sound harsh at close range. Others may have a very smooth high end and weak room coverage. A good balance between these two will make announcements more pleasing to your client’s ears.

Efficiency is another crucial consideration when selecting speakers. Some speakers require substantially more power to reach a 101 dB sound pressure level at I meter. Most speaker systems have this rating in their literature. Compare these numbers. The speaker that requires fewer watts to reach 101db is the most efficient. Speakers of greater efficiency require less power from your amplifier, allowing it to run cooler and avoid clipping. This can be a deciding issue between two speakers of similar sound quality.

Power ratings show the maximum power over a sustained period of time a speaker can handle. One common misconception is “you should never hook up a speaker to an amplifier with a higher power output than the speaker’s power rating”. Speakers typically can absorb short-term (several seconds) power surges as high as two to four times their power rating. Speakers with higher ratings may often produce higher volume levels and lower distortion than those of lower power ratings. Higher power ratings can also mean that a speaker requires more power to reach a high volume. Be sure to look at both efficiency and power ratings when comparing speakers.

Size and weight should not be overlooked. Many mobile DJs use 12″, 2-way speakers on stands as opposed to larger systems placed on the floor. Placing speakers on stands positioned above the heads of your audience allows greater room coverage. Moving speakers away from the floor and other hard surfaces reduces total bass output, however.

Your back may decide this one. Typical 12″, 2-way systems weigh about 35-45 lbs. 15″, 2-way and 3-way systems generally weigh between 50-85 lbs. You will need to decide which way you want to go to obtain the sound you will need.

One option you may want to explore, is to start out with a nice quality pair of 12″, 2-way speakers that you use on speaker stands, with the idea that you can add another set of larger speakers that sit on the floor for better sounding bass. With two 8 ohm speakers (one speaker per channel), you place an 8 ohm load on each channel of your amp. By simply adding another pair of 8-ohm speakers, you will then place a 4-ohm load on your amp, giving you more power output per channel. The concept of using one small and one larger pair of speakers is a convenient alternative that will add a deep, rich sound to your system without the hassle of going to a bi-amped system.

F. Processors

Processors make changes to the music signal. Generally, they are connected between the mixer and the amplifier. There are four basic types commonly used by DJs- equalizers, compressor/limiters, time alignment devices, and crossovers.

Equalizers are essentially a group of volume controls that adjust volume at specific frequency ranges. They are often built into mixers, and can be very useful for “cleaning up” a “muddy” or “bright” mix. Many sound engineers approach equalization as a “balancing act” rather than “add more bass” or “add more treble”. A mix that sounds muddy may simply have insufficient treble output, or it may be both insufficient treble output and too much bass. At the extreme end, it may simply be too much bass. The objective is balance and smooth sound. Because mobile DJs work in a large variety of rooms, an equalizer is generally a necessity. Most DJ mixers have equalizers built in for good reason. In the words of Toy Story’s Woody- “If you don’t have one – get one!”

Compressor/limiters selectively take a signal and reduce its dynamic range. The louder passages are no longer so loud, and the softer passages are easier to hear. They also limit the possibility of amplifier clipping and subsequent distortion if set properly along with a proper signal level. This can be very helpful when you’re trying to squeeze every decibel you can out of that best man who’s afraid of the microphone during his toast. These are more helpful in larger shows that typically cover a large area.

Time-alignment devices generally divide the signal into bass and treble content. The bass signal is released to the amplifier milliseconds before the high-end signal. This change often produces very noticeable results. Bass often seems fuller with more punch and clarity of high-end content; vocals seem to increase as well. The two most common units on the market are the BBE Sonic Maximizer and the Aphex Aural Exciter. If you are leaning toward smaller speakers, but are worried about their bass output, test drive one of these. I have a 12″ system that sounds dramatically fuller thanks to my time aligner.

Crossovers divide the signal from the mixer to the amp into two or three parts. This allows for the use of separate amplifiers and multi-speaker systems. Typically, crossovers are used to send lower frequencies (below 150 Hz) to a subwoofer and the upper frequencies to a full range speaker. This allows the full range speaker to produce those higher frequencies more efficiently, and the subwoofer to produce substantially greater bass output than the full range system. Crossovers have controls that allow you to adjust the “turnover” frequency- that is the frequency at which the signal does not pass through. They also allow you to control the signal output of each half of the total signal.

Subwoofer systems are more commonly used in high schools, colleges, and clubs where music content is often bass heavy.

G. Microphones

The mobile DJ will use his microphone often, and often at very critical moments. A high quality vocal microphone is relatively inexpensive compared to much other DJ equipment. The Shure SM-58, which is beyond question the microphone most commonly used by mobile DJs and professional announcers, generally can be purchased at just over 100.00 at many music stores. There are other great basic microphones in this price range also. You should avoid microphones that do NOT have an XLR connector. Some cheaper microphones will have a ¼” connector. This is very undesirable, and the trademark of a poor sounding mic. A cabled microphone is a must even if you decide on a wireless microphone; you should always have a backup.

Wireless microphones allow the mobile DJ to get away from his console and get out on the dance floor to teach, motivate, and PARTY with his guests. A wireless headset allows hands-free operation, but is impractical to hand to the best man for a toast. A hand-held wireless allows you to get out on the dance floor, but limits what you can say and do at the same time. Many DJs have both headset and handheld wireless microphones in their system. This allows them the flexibility to talk with hands free and allow others to talk without hassling with a wire or the location of the DJ area.

If you decide to go wireless, true diversity systems are the least expensive quality system available. UHF systems offer far greater range (ability to speak further from the receiver) than true diversity systems, but are more expensive. In the last year, however, UHF prices have dropped dramatically. Shop around on these. Also, be sure you can rack mount your receiver. A damaged receiver means a dead microphone.

H. Connections

Putting a group of components together in a rack means nothing if they are not properly connected. When budgeting a system, it is imperative that you price all the cables you will need as well. A typical DJ system will require at least 2 sets of speaker cables, one set of quality RCA cable pairs for every media player, a set of cables to connect mixer to amp, and any other cables required for microphones and processors. Heavy-duty power strips and extension cords are also a major necessity. Occasionally you may have to run an extension up to 100′ long. This cord should be no lighter than 14 gauge and 12 gauge if possible. Consider also rack-mountable power strips like the Rack Rider. The more cables you can keep inside your mixer case, the cleaner your setup will appear, and you will save time and wear by making fewer connections during setup. I highly recommend keeping a spare of each cable and connector in your system. Also keep fuses for mixer, amp, and speakers handy.

If you have media players (such as CD player or mini-disc) in a case other than your mixer case, you can decrease wear on your mixer inputs by running a second RCA pair to a pair of female-to-female RCA plugs attached to the mixer case just inside near the back. This is one of the many brilliant ideas I have stolen from posters at ProDJ.com. I would love to thank and credit that poster if I could remember who it was!

III. Casing

A. Transport

Transport casing refers to the carriers of cables, extension cords, microphones, and other miscellaneous items. For bulky items that are not especially fragile, there are many large cases available at very reasonable prices. For all my cables (and a few light chaser/controllers), I use a large plastic Contico trunk that cost just 19.99 at a department store. It is lightweight, has a strap handle in the front, and molded-in handles on each end. It has two latches and is stackable. I use a second for props. These hold a lot of maracas, inflatable guitars, and YMCA hats as well!

B. Equipment

The most common indicator of a “newbie” DJ is the lack of proper casing for their equipment. Newbies often stack a mixer on top of two home CD players and place their amp right beside them. I know, because I did this at one time too. Yes I damaged one CD player. Yes I tripped over hanging power cords several times. Yes my setup looked like a mess- a tangle of wires for all to see. When I became serious, I watched (and helped) some more experienced DJs. I soon discovered the two major benefits of equipment casing- saving your equipment from damage and saving a lot of time for setup/tear down. One other advantage of casing is that it offers a professional appearance to your system.

The most common equipment case for the mobile DJ is the mixer case. It includes slanted or pop-up rails to accommodate a mixer, wireless microphone receiver, and a dual CD controller. The bottom typically holds items like a power distributor, CD player. mini-disc player, equalizer, amplifier, etc. These cases have racks that are measured in “spaces”. A rack mount “space” is 1.75″ high x 19″ wide. A typical size for a mixer case is “8/6”, that is, 8 rack spaces on the slanted top, and 6 rack spaces on the vertical bottom. Be sure to measure carefully the requirements of your equipment before buying. Also keep in mind the TOTAL WEIGHT of the case once you have filled it. A large case may be more convenient, until you have to lift it.

Another common case is the SKB roto-molded cases. These are lightweight (compared to plywood & carpet cases), heavy duty, shock resistant, and close with a tight seal. Most of their cases are only vertical style, however. I have recently seen an ad for an SKB mixer case (a 10/6 pop-up model, but I have yet to see these in any stores or catalogs. A “workstation” version with a pullout drawer for the mixer is also available.

If you start out using consumer CD players that are not rack mountable, you can still protect these units in a case. This can be done by purchasing a regular rack mount case, and getting a rack mount adapter tray. One DJ I know uses velcro to secure the CD player to the tray, and in turn, velcros another CD player right on top of the first one. This protects your CD players, and also provides you with a more professional looking system.

IV. Sources of Information

The starting place for equipment information would have to include the Gear Board on ProDJ.com as well as Mobile Beat magazine. Talk to other DJs and see if you can help them. Many will be glad to feed you a lot of information in exchange for your “roadie” dues. Yamaha has an excellent manual on sound reinforcement that covers everything from beginner to intermediate and beyond. Salesmen at music stores may often have a lot of product knowledge, but you must keep in mind that they are paid to SELL and MAKE MONEY. They may not always have your best interests at heart. Check out catalogs from some of the major advertisers at ProDJ.com (click on Mall) and Mobile Beat magazine. Compare pricing when you shop and don’t be afraid to ask for a better deal- after all- you work hard for the money!

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Mobile Beat Staff Writer (228 Posts)

This is the general editors account for Mobile Beat Magazine and Website. Who reads Mobile Beat online and in print and attends Mobile Beat events? DJs, VJs and KJs to start with, especially those who own and operate mobile entertainment services. They provide music, video, lighting and a myriad other entertainment choices for corporate events, wedding receptions, dances and innumerable other gatherings.


Filed Under: Sound