Playback Rigs

The era when seriously powerful disco systems were in use was the eighties. Noise control was not a worry and Stage Sound designed and built most of the large playback rigs around Auckland during that 10 year period. In all about 200 systems. (Including many live band PA's as well.)

As time went by we learnt a lot from our early mistakes and developed a number of techniques that greatly improved the reliability of the audio systems we were installing. This was essential because we had so many systems in place at any one time that we could not afford to have several pack up simultaneously as we would not have been able to get to them all in time to prevent a major disaster for our valued clients.

The largest we built during this eventful period was for the Coliseum in Manual which could cater for well over 1000 patrons and was the biggest night club in the North Island. During its highly successful three year history we were never called out to do a service due to an electronic failure. This was because the system was built to last and designed to cope with the rigors of long term high level use. This system could easily exceed 110 dB on the dance floor and was always run at very high volume levels because the dance floor was the size of the average house. During the last 15 years very little has changed and the Coliseums music system would not look or sound out of place in a modern nightclub.

Some of the methods we used to greatly enhance a sound systems reliability are listed below:

• Our speaker boxes are made from timber rather than plastic so their acoustic qualities are far better. Plastic looks good but tends to sound clunky because it flexes in use.
• We use only professional speaker components with cast frames, large voice coils and magnetic structures. Not the cheap light weight types normally found in retailed boxes.
• Careful attention is given to speaker placement. There is no substitute for experience here and with well over 150 installations behind us we know how to do this correctly.
• We only use 3 way system engineering. This method eliminates the internal passive crossovers that have a bad habit of overheating and causing reliability problems.
• We pay careful attention to amp rack ventilation because thermal issues are the prime cause of power amplifier failure in high level playback systems. Where possible we use an extra fan.
• We will always try to ''hard wired' speaker cabling. Doing this eliminates plug in type connectors. These are another cause of unreliability because they tend to corrode if humidity is an issue.
• We always fuse protects the high frequency components using a rack mounted fuse panel. This means fuses can be changed without the need for a ladder to reach the speaker fuse holders.
• We install a 'hard line limiter' to prevent your DJ getting carried away and overdriving the sound system. This behaviour is another prime reason for catastrophic failure in powerful sound systems.
• We protect all signal processing equipment such as crossovers and equalisers with tamper proof covers so unauthorised persons cannot cause damage to the system by using incorrect settings.
• We use only quality connectors on interface cables to minimize cable faults caused by repetitive handling and aggressive actions when items are removed from the system.

There are a number of other techniques involved but these come under the category of trade secrets and as such are only available to paying customers. Realistically it is simply not possible to build a totally bullet proof system but the above precautions certainly go a long way towards achieving this aim. Modern amplifiers tend to be built to a price and are often deficient in cooling. Interestingly enough some of the lower priced power amps on the market have some of the largest heat sinks we have seen. Very few timber enclosures are made in NZ anymore because they cannot compete on price with most of the very cheap imported boxes from China. Many of these are not repaired if they fail rather they are simply thrown out and I definitely do not agree at all with this utterly wasteful philosophy. The best boxes we ever used were those we built ourselves and this is just as true today as it was 20 years ago when we were the main players. Its whets inside the box that counts not what it looks like. As a general rule the seriously professional speaker components are not available at retail level. This is because the extra profit margins involved make them too costly to sell in large numbers. One thing is certain their constructional quality is far better, their efficiency is higher, their power handling is far higher and their sound quality is superb.

The following is a price guide that some readers may find very interesting. These prices would be those charged by Stage Sound if we were custom building top quality enclosures using high end components that any experienced sound engineer would compliment. I have almost no idea what others who are capable of providing the same service would charge and I have no anterior motive for the offering the following information other than as a useful reference. These would be acid hardened screwed and glued cross braced correctly ported plywood enclosures with curved metal perforated grills and T bolts for speaker mounting. (No flying or mounting hardware is included in these prices) All prices are plus GST.

The performance of these enclosures would compare with any American or European manufacturers products, but at a fraction of the price. These are trade prices only.

Please note: The availability of the above enclosures is subject to local component stocks and acceptable lead-times set by us. Prices subject to international pressures and may vary depending on circumstances.

For any further information on this or other blog topics please call Paul Johansen on Ph: 444 8776