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Basic 100v system wiring guide

S
Srikanth S

This document provides guidance on setting up a 100v commercial PA system. Some key points include: 1) 100v systems operate at a high impedance rather than low impedance like a standard home audio system. Speakers must be wired in parallel to the amplifier outputs. 2) When wiring speakers, it is best practice to loop wiring from one speaker to the next rather than branching off individually. Speaker wattage settings should be adjusted to load the amplifier below its maximum rating. 3) Recommendations are provided for appropriate wattage settings for different types of speakers and room sizes to ensure adequate coverage while avoiding overloading amplifiers or drawing too much power. Proper wiring and installation is important to avoid

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Basic PA System Advice passound engineering 100v Systems Page 1 of 2 E: sales@pas-sound.co.uk T: 0845 430 0546 1 100v is a theoretical value based upon the system being driven 鍖at out into a full load, it is not constant. In reality this is a high impedance system as opposed to a low impedance system (4/8 ohms). So dont be fooled into looking for something that doesnt exist! 2 3 4 5 Speakers must be wired in parallel to each other and the ampli鍖er outputs (which are usually marked Common & 100v). Speakers do not need to be wired back to the ampli鍖er individually unless they are wired into separate speaker zones. It is normal practice to wire out from the ampli鍖er to the 1st or nearest speaker, and then on to any subsequent speakers. Looping in and out is best practice, although if you need to wire off to an existing circuit, teeing off is perfectly acceptable. Speaker loadings! It is normal practice to load a commercial 100v ampli鍖er below its maximum rating to ensure long life and reliability. As an example a 60 watt ampli鍖er could be loaded as follows: The 10 watt margin also allows for the odd extra speaker being required in the future.IT IS IMPORTANT THAT AMPLIFIERS ARE NOT DRIVEN WITH A GREATER LOAD THAN THEY ARE RATED! Add up your speaker wattage settings and ad just them if necessary to just below the ampli鍖er rating. As a rule speakers COME SET TO THEIR MAXIMUM SETTINGS and often these want reducing prior to installation. As most commercial speakers come with adjustable wattage settings (multi-tapped transformer) it is possible to adjust a speaker to suit its location. More often than not, a speaker only needs a small amount of power in a quiet location such as an of鍖ce and a moderate amount in a warehouse. Always try to keep back as much power as you can by keeping tappings as low as you can in order to do the job, then if you need to adjust one speaker UPthere is headroom in the system to do it without problem. 2 x 15 watt speakers 30 watts 1 x 10 watt speaker 10 watts 2 x 5 watt speakers 10 watts Total load 50 watts
Page 2 of 2 passound engineering E: sales@pas-sound.co.uk T: 0845 430 0546 0.75mm族 1.0mm族 1.5mm族 30 Watt Load 60 Watt Load 120 Watt Load 1066m 1600m800m 400m 533m 800m 200m 266m 400m 0.75 1.5 w 3 w 6 w 6 w3 w 5 w 5 w 10 w 10 w 15 w 10 w 20 w10 w 0.75 1.5 w 2.5w 5w 2.5w 5w Quiet Room/Area Ceiling speaker Wall cabinet speaker Small projection spkr Large projection spkr Horn speaker Pendant Average Area Noisy Area Basic PA System Advice 100v Systems 6 Speaker wiring can be done best with a double insulated twin 鍖exible cable such as 2182Y available from most electrical wholesalers and RS Components. It is important to wire all the speakers in the same polarity to ensure correct phasing. Failure to do this will result in some speaker cones moving out, whilst others move in, this results in a thin sound, lacking quality, level and tonal response. Please refer to the table below for recommended sizes of cable and their maximum distances. 7 It is industry practice to wire the 100v common output as the negative or blue conductor within the cabling. Keeping this arrangement throughout ensures all connections to speakers are made in phase. 8 Ensure all speaker connections are well made (particularly those where there may be disturbance in a ceiling) and secure,this will reduce the risk of a cable being pulled, connection broken and ultimately creating a short circuit on a speaker line which can result in a damaged ampli鍖er. A short can be detected audibly if there is low volume and a distorted output. 9 10 Ampli鍖er inputs Usually channel one is the paging microphone input, and connection via the Din plug will provide the access switching to automatically switch off any background music that is being broadcast thro ugh the system. The microphone can be extended away from the ampli鍖er if required, we suggest using a 2 pair screened cable such as Belden 9502 or equivalent to extend with. It is impotant to remember that this is two pairs of conductors plus a screen/drain wire and each pair has a function, one pair is audio, one pair is switching, the screen keeps the whole lot quiet! Set the ampli鍖er levels to a moderate level to start with when powering up for the 鍖rst time, this will avoid feedback and frightening anyone who happens to be close to a speaker at the time! Suggested starter wattage settings for speakers, these are not correct for every application but will get you going in the right direction.

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Basic 100v system wiring guide

  • 1. Basic PA System Advice passound engineering 100v Systems Page 1 of 2 E: sales@pas-sound.co.uk T: 0845 430 0546 1 100v is a theoretical value based upon the system being driven 鍖at out into a full load, it is not constant. In reality this is a high impedance system as opposed to a low impedance system (4/8 ohms). So dont be fooled into looking for something that doesnt exist! 2 3 4 5 Speakers must be wired in parallel to each other and the ampli鍖er outputs (which are usually marked Common & 100v). Speakers do not need to be wired back to the ampli鍖er individually unless they are wired into separate speaker zones. It is normal practice to wire out from the ampli鍖er to the 1st or nearest speaker, and then on to any subsequent speakers. Looping in and out is best practice, although if you need to wire off to an existing circuit, teeing off is perfectly acceptable. Speaker loadings! It is normal practice to load a commercial 100v ampli鍖er below its maximum rating to ensure long life and reliability. As an example a 60 watt ampli鍖er could be loaded as follows: The 10 watt margin also allows for the odd extra speaker being required in the future.IT IS IMPORTANT THAT AMPLIFIERS ARE NOT DRIVEN WITH A GREATER LOAD THAN THEY ARE RATED! Add up your speaker wattage settings and ad just them if necessary to just below the ampli鍖er rating. As a rule speakers COME SET TO THEIR MAXIMUM SETTINGS and often these want reducing prior to installation. As most commercial speakers come with adjustable wattage settings (multi-tapped transformer) it is possible to adjust a speaker to suit its location. More often than not, a speaker only needs a small amount of power in a quiet location such as an of鍖ce and a moderate amount in a warehouse. Always try to keep back as much power as you can by keeping tappings as low as you can in order to do the job, then if you need to adjust one speaker UPthere is headroom in the system to do it without problem. 2 x 15 watt speakers 30 watts 1 x 10 watt speaker 10 watts 2 x 5 watt speakers 10 watts Total load 50 watts
  • 2. Page 2 of 2 passound engineering E: sales@pas-sound.co.uk T: 0845 430 0546 0.75mm族 1.0mm族 1.5mm族 30 Watt Load 60 Watt Load 120 Watt Load 1066m 1600m800m 400m 533m 800m 200m 266m 400m 0.75 1.5 w 3 w 6 w 6 w3 w 5 w 5 w 10 w 10 w 15 w 10 w 20 w10 w 0.75 1.5 w 2.5w 5w 2.5w 5w Quiet Room/Area Ceiling speaker Wall cabinet speaker Small projection spkr Large projection spkr Horn speaker Pendant Average Area Noisy Area Basic PA System Advice 100v Systems 6 Speaker wiring can be done best with a double insulated twin 鍖exible cable such as 2182Y available from most electrical wholesalers and RS Components. It is important to wire all the speakers in the same polarity to ensure correct phasing. Failure to do this will result in some speaker cones moving out, whilst others move in, this results in a thin sound, lacking quality, level and tonal response. Please refer to the table below for recommended sizes of cable and their maximum distances. 7 It is industry practice to wire the 100v common output as the negative or blue conductor within the cabling. Keeping this arrangement throughout ensures all connections to speakers are made in phase. 8 Ensure all speaker connections are well made (particularly those where there may be disturbance in a ceiling) and secure,this will reduce the risk of a cable being pulled, connection broken and ultimately creating a short circuit on a speaker line which can result in a damaged ampli鍖er. A short can be detected audibly if there is low volume and a distorted output. 9 10 Ampli鍖er inputs Usually channel one is the paging microphone input, and connection via the Din plug will provide the access switching to automatically switch off any background music that is being broadcast thro ugh the system. The microphone can be extended away from the ampli鍖er if required, we suggest using a 2 pair screened cable such as Belden 9502 or equivalent to extend with. It is impotant to remember that this is two pairs of conductors plus a screen/drain wire and each pair has a function, one pair is audio, one pair is switching, the screen keeps the whole lot quiet! Set the ampli鍖er levels to a moderate level to start with when powering up for the 鍖rst time, this will avoid feedback and frightening anyone who happens to be close to a speaker at the time! Suggested starter wattage settings for speakers, these are not correct for every application but will get you going in the right direction.