|
This document gives advice on building and providing sound systems and lighting, specifically in relation to free parties.
- Starting off
- Rigs
- Types of speakers
- Drivers
- Amps
- Crossovers
- Cabling
- Generators
- Lighting
1. Starting off
Fortunately for beginners starting off, there is a huge amount of information available on the internet which will give you a background in Pa´s and sound systems. There are also many great forums where you can post your questions and get experts to answer them. However:
-Try to do as much background reading as possible before asking people on forums, chances are, you're question has already been asked and answered.
-Be weary of advice given. Some people may THINK they know what they're talking about, but get it wrong. Also, people often advise you that their drivers/speakers/amps are the best in order to make the sale and gain commission. Always get outsider opinions from lots of different sources. You’ll soon work out who know what they're talking about.
Best place to start off is a good pair of monitor speakers. By good, i mean a 15/12" driver with a larger voice coil (300-500w), a good compression driver and high powered passive crossover. Active speakers are ideal as monitors and far more convenient. A good
set would be anything by RCF/MACKIE, EV, or JBL (except eons). Make sure it has separate bass and treble amps built in.
A good reliable pair of 3-500w speakers are very easy to hire out and this will be where most of the income is to be made. So it is worth the investment. An added bonus is the fact that you can stop DJ's rinsing the gains on your mixer by running the monitors off the same output as the rig. If the monitors are good, then they cannot physically turn up the mixer too much as it’ll be too loud.
2. Rigs
Common practice for some people starting to get a rig together is to snap up any cheap deal on e-bay, trade-it or from mates and put together a mish mash of lots of different types of boxes, amps and cables. Try not to be too eager and spend some time thinking about what you need and planning it. There's no point in buying something, then selling it a year down the line when you've learnt it's no good.
Bigger is not always better. The size of stacks is somewhat based upon ego and many people get excited over showing off a big wall of black boxes. There is a lot of competitiveness in the free party scene between rigs, which is a good thing, as it means that the sound systems get bigger and better each year. However, many people get carried away with size, and forget about all the other important elements which make up a good party (location, lighting, music, bar, atmosphere, sound quality etc). Remember, people will be much more impressed with a very small, clean and efficient rig and interesting set-up. Offering something new and different. The advantages of having fewer speakers are obvious:
-Easier to transport. You can use a smaller van which will attract much less attention and be harder to spot by the police.
-Easier on your back, speaks for itself!
-Quicker to assemble and setup
-Less storage space required.
Remember, the golden rule of a good sound system uniformality. Try to keep everything the same! ALWAYS use the same drivers and enclosures in each of your crossover bands. I.e. All 18" scoops as bass, all front loaded 12" drivers for mid etc.
Different drivers and different enclosures have different characteristics. Using different designs will mean the sound will be arriving to your ears at different times and you will not see much of an increase in volume, no matter how many speakers you add. You also colour the sound so it is not as "clean"
3.Types of speakers
Bass?
Bass reflex V's Horns
These are the 2 main types of loudspeaker designs. Bass reflex works on the principle that air is "springy" and increases the bass extension of a speaker by allowing sound to escape through a hole in speaker box. The size of this hole must be calculated exactly.
These designs give a much lower bass extension from smaller/fewer boxes. Properly designed, they give a very flat response and a nice sound. They are also far easier to construct and generally cheaper.
For small sound systems up to about 5k, and for small to medium sized venues, these are ideal and a good first system. However, they lack the efficiency and "throw" of horns but often give a warmer sound. They also come in band-pass designs, whereby the sound only escapes through these “holes”. This gives deeper and more efficient bass, but some find it can slow and color the sound. Again, it is all about compromise.
Horns work by allowing the sound to expand at a controlled rate from the speaker. The length and volume of the horn dictates the lowest frequency will get out of the speaker. This is the golden rule and the problem behind them. In order to produce bass down to 30hz, you would need a horn several meters long. This can be folded up (hence the phrase "folded horn"), but still requires large enclosures of complex design. This low frequency "cut-off" can be extended by stacking lots of the same bins together to increase the size of the mouth of the horn, but generally requires at least 6 bins. Hence, there is little point in using horns unless you are planning to create a large system for large crowds/venues.
Consider the type of music you will be playing and decide how low you need to go. For techno, a short folded horn is ideal as it will give you the "punch" and are fairly compact. However, these will not do for something like dub or jungle, where you need large horns to get the sub bass extension. look to something like a Lab horn, 1850/loony bin, bassmaxx or scoops for this.
This is the reasoning behind why i dislike the bass in sound systems like Turbosound and Thunderidge, as the short horn of the bass bins cannot reproduce these sub bass frequencies I love.
The idea behind using a horn loaded system, is that the horn makes the speaker more efficient. Consider a horn adding 3db to the efficiency. 3db relates to a gain of 10, or twice the perceived "loudness".
Horns may seem ideal, but companies charge thousands for a good horn loaded system. The best way is to build your own. Sites such as www.speakerplans.com and www.prosoundweb.com/lsp contain designs. Also, look for the Selenium construction plans page too for some great folded horn and top cab designs.
Building horns right is very difficult and time consuming, but very rewarding. Start with something small like a monitor to get the feel. ALWAYS get your wood cut at a carpenters/joiners if you are unsure. Pieces that don't fit together properly
causes gaps where air can escape and your box can disintegrate. Building several at a time is often as easy as building 1 and don't forget to allow room in your budget for paint, castors, handles, speakons, cable etc.
Mid/tops
With the bass sorted, you need some clean and clear mid/top. For small venues, a simple 12/15” driver and 1” compression driver on a CD horn, crossed over properly, can’t be beat. Emphasis is in the quality of the drivers, and the setting up of the amps/crossovers.
For larger venues/rigs, there are two main directions. Almost all sound systems use a 12” driver, horn loaded or not for the 200hz – 1.5khz band. Above this, either a 1.5 or 2” compression driver is normally used. Although very loud and efficient, poor quality drivers/horns of this size can be very harsh and ear piercing. They also cut off at about 10kHZ (no matter what the manufacturer says) so you should always add a couple bullet/slot tweeters to give the clarity and sizzle that will add fidelity to the sound. Remember that a 2” compression driver has a very high sensitivity. You will need not one, but two 12” drivers (preferably on a horn) to keep up.
Companies like Funktion One and Turbosound dislike these large compression drivers so much, they have ditched them for 6/8” cone drivers on complex phase plug horns, with a smaller 1” CD for the 5khz plus range. Arguably giving a much nicer sound, the downside is that the smaller 6” horns cannot be constructed or bought. You must therefore, either pay a lot for these speakers or await these molded horns to be sold on their own.
Compression drivers and horns are often fairly expensive. If you are on a tight budget, go for a cheap 12” driver and an Eminence apt150 on a high pass filter. If you can afford it, a 6” in between will make things nicer if the right crossover is used. Whatever you do, don’t think you can get away with using piezo tweeters! They are harsh and horrible and will blow like light-bulbs.
4. Drivers
It is important that the speakers power handling and parameters matches the box you put it in. The behavior of the loudspeaker is defined in the Thele-small parameters. An explanation of these is easily found. These parameters are especially important in band-pass/reflex designs.
For horn loaded designs, look for a speaker with a low qs and high bl. This relates to how quickly the driver responds and its strength. A large voice coil is important too.
Most manufacturers produce good speakers. The difference between the budget and the high-end, will be the lifetime of the speaker and its power handling. E.g A Precision devices 1850 and a Eminence Omega pro have the same 600w power handling, yet the PD driver will happily handle 1200w due to its better design and larger voice coil.
Beware of JBL drivers. They are overpriced and overrated and tend to blow a little too often!
Compare drivers on their x-max, voice coil size, sensitivity, and magnet size.
5. Amps
Your amplifiers are the backbone of the sound system. Good amps are somewhat more important than good speakers. Consider the fact that companies build amps mainly for use in clubs and pa companies, where they will not be driven too hard, only be on
for a few hours at a time, and live in clean, cool dry conditions.
Now consider using these amps in a dirty dusty warehouse, or damp/dusty field, running flat out for days on insufficient/dirty generator power. Not to mention the cheap and dodgy "last minute" cabling that you often see. This is where you will see the difference between the pro amps and the cheaper ones.
A good amp will:
-Have built in clip limiters (to protect the speakers)
-Thermal warning/shutdown
-Load tester (wont blow up if you short the output terminals)
-Be stable at 2ohms a side
-Have a good power supple (switched mode or use oversized torroids)
You will always get what you pay for, these companies are especially good:
Crown, QSC, Crest, Lab-Gruppen, Cheverin.
Also, always take the manufacturers power ratings with a pinch of salt. For example, the PV2600 is rated at 900watts a side, but was outperformed by a 600w a side Crown amp.
If you are on a budget, the Behringer Europower amps are the way to go. They are very similar to the QSC RMX series. Offer full protection circuits, but the weaker power supply struggles running subs at 2ohms. T-amps are also cheap, but I’ve heard mixed reports on their reliability.
Finally, people always ask "what size amplifier is right for my speaker?" the golden rule, is to try to use an amplifier of 1.5 to 2 times the rms rating of the speaker (depending on how good the driver is). That way, you should always have enough headroom and never be clipping the amplifier.
Remember to make room in your budget for a professional flight case amp rack. You may want to separate your amps into 2 or 3 racks to make transport and carrying easier.
6. Crossovers
For any sound system over 1k, ALWAYS use an active crossover. This will split the signal before it reaches the amps, meaning you don't loose power in the resistive crossover circuits.
You can add more crossover points as your system gets larger. For large, horn loaded systems, a digital speaker-management system is essential. The bass and top horn lengths will be very different. As sound travels at only 330ms, the sound coming out of your bass bins will be a few milliseconds behind that of your tops. This is very noticeable. A SMS will allow you to delay outputs so you can get each part of your system in "phase" with another so the sound arrives at your ears at the same time. It also has many useful limiter and eq features.
7. Cabling
Almost every problem with rigs at parties is related to poor wiring. Cables are something that is often overlooked until the end and then corners are cut. A little extra time and money spent on a good wiring system pays for itself in the stress you will save. Buy a rack mount plate with drilled holes for the front of your amp rack. Here you can mount your speak-on sockets and xlr inputs. This way you only have to wire and setup the amps once and don't have to dive into the mess of cables that is the rear of an amp rack.
Using 4 or 8 pole speakons means you only have 1 or 2 cables to remember and plug it. It saves a LOT of time and can even work out cheaper than have 4 normal cables. Consider yourself in a dark field with a million things to do like get power sorted, set-up decks, lighting, decor, directions, safety and security. The last thing you want to be doing is trying to work out where your 20 speak-ons go and searching for that missing signal cable. Set-up time is the time when you are most at risk, so you want to minimize it.
Finally, NEVER use anything other than speakons for wiring your speaker cabs. People stopped using jacks and xlr's years ago and there's a reason for that!
8. Generators
If you are planning to do parties outside, or in buildings with shot electrics. Then a reliable generator is essential. Hiring generators is easy (HS, Brandon tool hire etc) but very expensive. Cheap generators are always for sale on e-bay and in the local free ads.
Start with a small and reliable 2-3k petrol generator that can fit in a car. This can run things if you want to do a small party, or run lights at a large one. Being quiet, you can run this from the time you arrive, giving you lights to set-up with.
A larger deisel generator can then power the amps and decks etc. It is very difficult to determine how much power an amp actually draws, but to be safe and allow headroom; it is advisable to use a generator of the same Kw rating as your amps. Be careful, some generators are rated in Kva, which is different to Kw.
9. Lighting
Often overlooked and arguably in it its importance, I believe the lighting and atmosphere is as important to a party as the music.
Lighting can be very expensive, but do not be tempted to go for the cheaper “disco-tastic” option (the multi-colored types without gobo or color wheels). These will ruin any ambient atmosphere and turn things into a cheesy school disco. They are also very annoying to look at and tend to drive people away.
Instead, build things up slowly. Start off with a UV tube or UV-cannon. Cannons are worth the investment if you can afford them, as they are more powerful and won’t smash every week.
The best and often most overlooked lighting is using Par-cans. Simply lighting up areas with purples, reds, greens, blues always creates a great atmosphere. They are especially good if you point them up into trees or at walls. There are stupidly cheap, costing as little as £16 each and will not break. They do, however, eat up power very quickly.
If you decide to spend some money on moving lights, its worth saving up and making sure it is able to DMX. DMX 512 is a way of linking and controlling lights so they work together. Something like an Abstract Twister 3/4 is a great light and pretty cheap second hand. Scanners also look great, but tend to be very expensive for anything good, and fragile (requiring a flight case). By buying lights of the same brand (e.g martin, abstract etc) you can link them together directly through DMX. A DMX controller can be used to create great effects. Make sure you get a programmable one with sliders.
The problem comes with the setting up of lighting. It generally takes a long time to place them on stands, supply power to the lights, and DMX them together. To cut time down, it’s worth investing in a long T-bar with a winch, which can go above the DJ. The lights can be set up earlier and simply winched up. When you do a party, have a group designated to the setting up of the lights separate to those doing sound.
Strobes are a touchy subject. Used properly, they are wicked, but tend to get left on for longer than they should. Buy a push to make switch for controlling them, so they cannot be left on all night!
Finally, remember that lights can be seen from miles around at night time. If you turn them on too soon, you may attract unwanted attention to the party.
| 
-Dave