LeftPress PA handbook

Table of Contents

  1. Introduction
  2. Old System – CS Power Column
  3. New system – Chiayo Challenger 1000
  4. Checklist
  5. Setting up the new system
  6. Setting up old system
  7. Capacity of PA
  8. Safety
  9. Sound Systems
  10. Feedback
  11. Leads
  12. Restrictions on public assembly
  13. Not a Permit System
  14. Squares and parks
  15. Preparation for meetings and public rallies
  16. Pick up
  17. Parking
  18. Sound Check
  19. Venues
  20. Speakers Corner
  21. Reddacliff Place
  22. Queens Park
  23. Cost of hire
  24. AppendixTechnical manual for Chiayo PA system


  1. Introduction
    Sound at rallies and meetings involves problem solving and some technical knowledge about how sound works. Recently I was at a film showing where there was an audience of about fifty people attending the Q&A at the end of the film. They had a computer link to guests from interstate, the film director and one of the sponsors of the film. However the cinema did not provide a PA system or roving mic for the people in the audience. All that was required was for a PA system like those that we describe below to be set up in the room prior to the film showing and the sound could then be heard by both the people online and, importantly, the audience in the cinema.

We describe solutions below for organisers of public meetings and rallies.


LeftPress has two public address systems used to amplify speeches at public meetings and rallies. They are:

  • Old SystemCS Power Column (PEM model) – with four TOA speakers mounted on two stands. These TOA speakers have been in operation since the right-to-march campaign (1977-78). We purchased the box and amplifier in the early 1990s. It has a pleasant warm sound and comprises five speakers in a wooden box covered with brown carpet. The speaker box has a variety of inputs and outputs using leads to the microphone(s). It is entirely portable and can do crowds up to 1,500 – 2,000 people. We call this the old system.
  • New systemChiayo Challenger 1000 Portable Wireless PA System. It is very versatile capable of providing sound to small audiences in a meeting room. Also it can supply up to eight (8) TOA speakers with sufficient sound to do crowds up to 10,000 – 15,000 people. It features a wireless microphone and Bluetooth system capable of playing high quality voice and music sound. We call this the new system. For a full technical description of the latter see Appendix – Technical manual for Chiayo PA system
Hiroshima Day 1978

4. Checklist. Regardless of the system being used, there are some things that will always be required.

Here is a short checklist:

Microphone plus Mic Stand. Check to see if more than one microphone is required e.g. when a choir sings. Extra mic stands may be required also.

Wire to connect phone or musical instrument to PA via Auxillary input (see Picture 2).

Charge the Battery charged for 10 hours before use. It is important for the life of the batteries to keep them fully charged. They are of the lithium-ion type. Charging both is easy. Plug in the power lead and turn on and the 240V supply begins charging the batteries. In the case of the old system you will need to plug in the battery box into the back of the PA box and it will begin charging. This step in unnecessary in the new system because the batteries are inbuilt.

PA stands and speakers. Work out beforehand how many horn speakers (TOAs) will be required. Note that either the (CS Power Column) or Chiayo Challenger 1000 will always be required to power the other horn speakers. See Table – Capacity of PA to estimate number of horns needed.

Leads. Long leads for each speaker. Count the number of horns and make sure you have the right number of leads and connector boxes.

Will auxiliary power be needed for musos amps?

Umbrella and covers for speaker box.

5. Setting up the new system (Chiayo Challenger 1000)

i. To set up the Chiayo PA system is a two (2) person job. The PA stand and box are quite heavy. To compensate for this, the PA stand is fitted with geared mechanism for winding up the speaker box.

ii. Place the stand near to where you wish the speaker box to be. Spread out the three (3) legs forming a tripod and tighten the knob that controls the legs. They should now be fixed.

iii. Bring the Chiayo speaker box on its two (2) wheel trolley  And place it next to the speaker stand. Make sure the height of the speaker stand is set to its lowest level. Two (2) people will be required to lift the speaker box up on top of the stand and to place the bottom hole on the top of the stand.

Main speaker on stand

iv. Place the trolley to one side so that people will not trip over it. OK this is how it should look (pictured).

v. Using the handle provided crank the Box up to a higher elevation. This will enable the better amplification of the sound to carry over the heads of the people or any obstructions. Make sure the knob is loose when you do this otherwise it will be difficult. Depending on the circumstances the speaker box should be about head height. Make sure you shut the handle and put it away. There is a trick to this, you must pull the handle out and slightly upwards in order to place it in its container (pictured).

vi. If you intend using the horn speakers then position the stand in the appropriate place.height or a little above.

Winding handle in the ‘in’ position
Winding handle in the out position

vii. Splay out the tripod legs making sure that you have opened up the knob that controls the legs.

viii. Place the horn speaker bracket on the stand making sure that it is at its lowest settings. Now place both horn speakers on the bracket making sure to tighten the knobs. Using the telescope of the stand making sure the knob is not tight and rise the speakers above head height.

ix. Now plug in brown cable to the external speaker and connect to small black connector box labelled (pictured).

Typical connection from amp to round TOA speakers.
The wireless mic is beside the connection box.

x. Now hook up the two (2) round TOAs and point them the direction you wish and you’re ready to do a sound check.

xi. Turn on the power and you will see some flashing lights and at the top of the back of the control panel you see the wireless mic being picked up on the UHF screen showing the number 520.250 MHz which is the frequency.

xii. Now turn on the mic. You should be able to hear the sound coming through the system. Check all the TOAs to make sure the sound is coming through them.

xiii. Stand in front of the speakers and speak gently into the mic. Get someone positioned in the crowd to see if the sound is carrying to the required spot saying “testing testing, one two”.

xiv. The wireless mic should be solid blue. If the blue light on the wireless mic is flashing that means you have to replace the 2 x AA batteries by unscrewing the bottom part of the microphone and putting in two double-A batteries and that should fix the problem.

If for any reason the wireless mic is not working, always have on hand the microphone and lead so that you can plug it into the microphone input on the back of the control panel.

To dismantle a system is the opposite of how you set it up. Lower the speaker box, disconnect the cables and placing one foot on a leg of the speaker and with two people then lift the Chiayo PA box upwards and off to one side lowering it carefully onto the trolley.

6. Setting up old system (CS < Power Column PEM model)

LeftPress portable PA ‘old system’ with battery showing control panel on back of speaker box.

This PA has four horn speakers that have been in operation since the right-to-march campaign (1977-78). The main speaker box was bought in the early 1990s. It has a pleasant warm sound and comprises five speakers in a wooden box covered with brown carpet.

The speaker box has a variety of inputs and outputs pictured below.

It is entirely portable having a small box carrying two 12V batteries (in series). This is fully chargeable by 240V supply through an extension cord (shown).

It has extension speaker outputs to two sets of TOA horn speakers. The whole system can be run independent of power restrictions in a square or on a footpath for eight (8) hours.

The back panel can take 2 mic leads and an auxiliary (e.g. guitar lead, phone or MP3 player).

7. Setting up

This is similar to the set up procedure for the new system but I will run through a checklist to make sure people understand how the old system works.

i. Place the PA box on a stand (there is a hole under the box to accommodate the stand).

ii. Plug in either portable battery or mains input depending on what power source you are going to use.

iii. Connect up PA box to old horn speakers (the squarish ones) using connector cables. This will be necessary depending on the size of the rally. The rule of thumb is if the small box does not deliver sufficient sound, add on as many horn speakers as needed to provide sound to the entire crowd. See Table below titled Capacity of PA.

iv. Plug in mic (and other sound sources) into the panel on the back.

v. Make sure levels are set to low so that when you turn on the mic (or other sound sources) there will be no feedback.

vi. Make sure the mic stand is set behind the PA stand and horn speaker stands (or, if this is not possible, make sure they are directed away from the microphone). This is prevent feedback.

vii. Turn on power switch on the PA box.

viii. Turn on mic switch (found at the top of the microphone).

You are now ready to do a sound check. If you are going to play music through a phone (or some other device) now is a good time to plug it in also. Get someone to go and stand near each horn speaker and check that sound is coming through.

If one of a chairperson or organiser is available ask them to make an announcement to check the levels. Make sure the organisers are happy with the positioning and direction of the speakers. Adjust the mic stand to the height of the chairperson and monitor this when new people come to speak.

You will need to check the levels by walking around the crowd and throughout the rally (as numbers may rise).

If there is to be a march make sure that someone is left to keep an eye on the equipment. If there is any heckling or interference with the microphone/PA speakers you will have to intervene to protect the equipment and to ensure continuity of the rally or meeting.

To dismantle the system is the opposite of setting up. Make sure you turn everything off to save the battery power.

In wet conditions you will need to cover the microphone and the PA box with a plastic bag or umbrella. The horn speakers will operate in wet conditions and do not need to be covered.

7. Table – Capacity of PA

Size of rallyVenueEquipment needed
< 200 peoplePublic hall or small outdoor spaceMain speaker box (CS Power Column)
< 200 > 400 peopleOutdoors or public hall2 TOA horn speakers and 1 spk. stand
< 400 > 2,000 peopleRally in square or public park4 horns and 2 spk. stands

8. Safety
Safety is a big issue because:

i. You are dealing with electrical equipment. Fortunately most of the leads have low voltage and can’t really hurt you. However the power leads to mains supply should always be rated for wet conditions especially extension leads.

ii. Some of the equipment is quite heavy: PA boxes, speakers, even the stands. Make sure you work in pairs and do not try to lift the equipment unaided.

9. Sound Systems
The primary objective is to convey speeches to people attending a rally or meeting. It may do other things like amplify music. It may be used to give important instructions or to send out chants and slogans.

This primary object means that the sound must be at the right level, it must be constant throughout the rally i.e. not be too loud or too soft. To do this requires having the correct equipment, and doing a surprising amount of work to monitor the sound. To do this properly is a job in itself. So at least one person (but preferably two people) should be nominated to do sound. Other people may need to be on hand to help carrying the gear and to look after the equipment. Do not leave the PA unattended.

During the rally the sound person will need to focus on the microphone, its stand and the control panel on the PA box. If a speaker has a soft voice or is nervous, it is the job of the sound person to reassure the person and encourage them to stand up to the microphone and speak clearly into it. The mic stand must be adjusted to suit each speakers height. Allow more confident and practiced speakers to do this themselves but discourage them from taking the microphone out of its cradle unless absolutely necessary. This can produce unwanted side effects e.g. feedback (see section below). The mic stand has been placed where it is for a reason. It may be provide the best vantage point for people attending the rally. It is important that the audience can see the speaker. If the rally is likely to continue into the evening then adequate lighting should be provided. Hardware and tool suppliers sell portable battery operated lighting.

Ext Speaker output

The LeftPress PAs are unlike sound systems you will see at a concert (for example).  Firstly, it is a public-address system primarily intended to carry speeches to a crowd of people (large or small). Secondly, it is a distributed system which means that the speakers are distributed among the crowd and connected by leads to a central amplifier on the PA box (be it the old or new system). In the new system the leads go from speaker to speaker as far as the edge of the square or park. This means we do not need big powerful speakers turned up really loud to make it possible for the people at the back to hear clearly words being spoken. A distributed system means that the PA and speakers need to be placed intelligently to take advantage of the topography. For example, Emma Miller Place in Roma Street is an amphitheatre; so, if the mics and speakers are placed on the concrete stage at the bottom, the sound will be broadcast upwards to the tiered grassy area at the back. On occasion attempts have been made to broadcast sound with speakers at the top of Roma Street Forum.  To do this requires a more powerful system with the sound bouncing off the walls of the buildings opposite. This may be undesirable for a number of reasons e.g. lack of clarity. With a well directed set of speakers using the natural shape of the amphitheatre will give sharper, clearer sound without side effects.

Photo of PA System showing horns, wireless mic, PA box (amp.) and stands

10. Feedback
One of the biggest bugbears for a sound person is feedback. This is the shrill sound that the PA emits when sound usually coming from an incorrectly directed box or horn speaker goes into the microphone and is amplified. The mic sends the sound to the amp which increases the level and so on. This is called a loop. It can damage people’s ears (accoustic shock) plus, if left unchecked, it can damage the equipment.

As soon as the feedback loop starts the sound person must turn down the mic level on the control panel. This means you have to be nearby. If the sound is extreme, you may need to turn the mic or other input off completely until you find the cause. Sometimes another input device can be the cause. However if you have only one microphone on it will be the sound level or a wrongly directed speaker. When someone is speaking at a rally you should only have one microphone turned ‘ON’. Even if you have other inputs (e.g. a guitar) you do not need to have the volume turned up until the guitarist is performing.

+++ This handbook is written for users of the LeftPress PA systems and for members of LeftPress. +++

LeftPress Printing Society is a socialist enterprise for the promotion of socialist literature and other original works.  We have over 30 years’ experience providing PA sound systems to public gatherings, large and small, in a variety of different venues. Our aim is to provide a resource to organisations at cost. We will do this so long as the aim of the rally or event does not contradict our purpose. LeftPress is run by a committee of workers dedicated to the abolition of private property and its replacement by the institution of worker control of production. Our purpose is to replace capitalist production with socialised industry. We charge a modest fee in order to maintain the equipment.  By arrangement, a LeftPress member may be present at the rally [there is a small extra charge for this].

11. Leads
Many leads may be necessary for use in a rally depending on size and equipment used. It is important to check the leads that will be required. Leads have a habit of failing because of being trodden on and general mis-use. The covers can be used on or near the podium where people are likely to tramp. This is a safety issue. One way to overcome this is to tape down the leads and place them in nooks and crannies where people can’t tread on them. Covers may be used. It is important to coil up leads without kinks or twists in them and to bind them with rubber bands or velcro. Here are some examples of leads that may be required:

12. Restrictions on public assembly
Commercial and privately-owned space has encroached on public spaces in Brisbane and, no doubt, elsewhere. The regulators of public spaces are Brisbane City Council, Queensland Police, State government and a number of corporations (e.g. South Bank Corporation and Treasury Casino). 

The prevailing principle that underwrite these public spaces is codified in Queensland law:

“A person has the right to assemble peacefully with others in a public place.”

– s5 Peaceful  Assembly Act 1992

There will be no shortage of private businesses, police, council employees, and private individuals who will tell you otherwise.  There are legal restrictions on this principle but they are limited by it. Most of the restrictions are common sense like protection of the rights and freedoms of other persons and public safety i.e. during the Covid pandemic we are required to practise social distancing.

The right of peaceful assembly was hard won by workers, their organisations, women, students and first nations people. So, we must not surrender these rights to organise cheaply and should challenge any government or private company that wishes to take away our rights of public assembly and marching.

12. Not a Permit System
Under the Peaceful Assembly Act 1992 you are required to provide an Assembly Notice to the Commissioner of Police five (5) business days before the event. A similar notice to the Council may be required if the square or park is under the control of the Council.  Contrary to what police, council and even some rally organisers may tell you, this is not a permit system.  If you fulfil these requirements the rally is lawful under the Act. If police or council object to the holding of the rally or march, they are required to go to court to seek an injunction prohibiting the rally or march or changing the time and place.

As recent court cases have shown, there is not guarantee that the courts will uphold the objection of either the Police Commissioner or the Lord Mayor.

Be mindful that the holding of a rally for a political purpose is not simply a question of legality, it is a question of democratic rights and organisation.  For example, if 10,000 people turn up to a rally in King George Square, there is very little the police or council can do, save to regulate the traffic and make sure the square is available.  LeftPress has the PA equipment necessary to make sure the audience can hear what is going on and that people can exercise their democratic rights, even if it is in opposition to the government of the day.

13. Squares and parks

As at 2020, the squares and parks where political rallies/events are held include:

Public Place and LocationAuthorityNumber of peopleFacilities/Toilets/Notes
King George Square
City Hall
Brisbane City Council BCC.< 10,000Yes (behind café, under square & in City Hall) plus water tap.
Queens Park
Cnr Elizabeth & George St.
Treasury casino/State government< 5,000No Public Toilets (have to go into casino)
Emma Miller Place
Roma Street

BCC< 5,000Public Toilets but a request is needed for them to be opened
Reddacliff Place [Brisbane Square]
266 George Street
Brisbane City
BCC< 500Public toilets (near café), cafe and drinking fountain
Musgrave Park
Cordelia St South Brisbane
BCC / Jagera Community Hall Management Committee / State government< 15,000Public toilets (near croquet club), this is a sacred aboriginal place on lands that were never ceded.
Exhibition Showgrounds
Gregory Terrace
RNA< 50,000Toilets near showground. May Day is held here each year on the first Monday of May.
Post Office Square
between Queen & Adelaide St
BCC< 500Toilets underneath.
Speakers Corner
Parliament House
George Street
Speaker of the Parliament< 2,000Nearest toilets at QUT
University of Qld Forum Area
UQ Students Union, Circular Drive, St Lucia
UQ Students Union / UQ< 150Refectory and toilets
Bunyapa Park
Cnr Thomas &Vulture St West End
BCC< 120Public toilets and water tap
Raymond Park
Next to Pineapple Hotel Kangaroo Point
BCC< 2,000Public Toilets and Community Garden

Public squares and parks may contain commercial activities (for-profit) that threaten rights to public assembly e.g. markets, coffee shops, bars, rides, stalls and karts, personal exercise trainers etc.

14. Preparation for meetings and public rallies.

Hiroshima Day 1978

LeftPress has a contact person who is on call to book the PA. When rally organisers contacts LeftPress, we generally ask the purpose of the rally, the venue and approximate number of people who will attend. All are factors are in determining what equipment will be required and how portable it will be needed to be. We have drawn up a table below giving a rule of thumb of what will be required for different events.

15. Pick up
Arrange for a convenient pick-up time by phone or text.

When you pick up the PA equipment from LeftPress briefly run through the checklist above be sure you have all the equipment needed e.g. enough mics, leads and extra speakers. Check that the green light is on when you connect the battery pack to the main box.

Arrange with LeftPress for a convenient time to return the equipment. On return of the PA Leftpress will issue you with an invoice with payment details on the form. Please provide LeftPress with your/organisation name and email address. Equipment should remain neatly packed in containers and bags provided until the rally.

If weather looks bad always take a couple of garbage bags and an umbrella to cover the older PA box and mic. The TOA speakers work OK in the wet. The newer Chiayo system has its own cover.

16. Parking
Parking is always an issue when attending rallies in the CBD. Make sure you have someone ready at the drop-off near the square or park to help you take the PA out of the car and to look after it while you park your car.

Take care to find a shady spot (if possible) for the mic stand so that the speakers at the rally will not have to stand in the hot sun. An umbrella is an important item to have on hand, be it rainy or hot.

17. How sound behaves in squares and parks
It is important to assess the public spaces where gatherings may occur. We are going to give an assessment of how sound behaves in typical public spaces in Brisbane. However these rules of thumb may apply anywhere.

Emma Miller Place with arrows showing the directions where the horn speakers should be pointing.

It is important to point the horn and box speaker at different sections of the crowd. If people are seated in a semi-circle as occurs at Emma Miller Place break it up into slices and point the speakers at each section as shown in the picture.

18. Sound Check
When the equipment is set up and connected with power, it is important to get someone to go to different sections of the square/park before the rally gets under way to check that sound levels are right. Also, if the organisers wish to play songs/music using their phones or if a musician(s) are performing at the rally make sure they have appropriate connector(s) before the rally. Devices (phones) and instruments may be able to connect to the new system wirelessly via bluetooth. This needs to be checked prior to the rally.

It is a good idea to monitor the sound levels throughout the rally because, as more people arrive, you may need to change the direction and elevation (height) of the horn speakers.

19. Venues
Each venue have their own sound characteristics, capacity, facilities and comfort levels. We summarise some important features in the galleries below.

20. Speakers Corner
This was set up in 2010 to accommodate the large number of rallies and protests that occur at the gates of parliament over the years. On occasion the gates have been breached by people angry at inaction by the government of the day. The space provides quite a lot of shade and is generally cooler than other parts of the city because of its proximity to the botanic gardens which are next door. The speaking equipment can be set up in a variety of ways depending on the size and nature of the rally.

i. Facing away from the speakers corner plaque. This enables the speakers at the rally the comfort of the shade from the tree behind and also takes advantage of the length of the space. The space is only about 20 metres wide but about 80 metres long. Not all of that space is available because cars park at the entrance to Alice Street. Some union rallies have had a stage where speakers corner is, taking advantage of the corridor in front of the stage. Sound travels well in this space.

ii. Facing away from Parliament and toward the Botanic Gardens. This has the advantage of confronting the monster with the audience at the back. Government Ministers and MLAs often come out and listen to the speeches from the extra-parliamentary opposition. In that case I generally turn one horn speaker around to face the parliament.

iii. The reverse.

Speakers Corner, George Street parliament house – Qld Uncut rally at gates of parliament – October 2012. Photo: Rick Ng

21. Reddacliff Place

Reddacliffe Place: Top of the mall – 266 George Street Brisbane City. Note that the LeftPress old system (inset) is providing sound for this rally.

This is an interesting space between the busway and the Brisbane City Council Administration building. City Council has quite a schizophrenic approach. They direct organisers to this space when KGSq has commercial activity going on in it. Yet they say that demonstrators must make way for pedestrian traffic.

22. Queens Park
Bounded by George and Elizabeth Streets and North Quay this park is under the control of the Treasury Casino although State government has some input into who uses it.
Measuring 100 metres by 100 metres it is one of the largest parks in the city capable of holding over 5,000 people. Recently it held about 20,000 after police shut down George, Elizabeth and North Quay. The sound system has to be set up carefully when the crowd gets that big. At the 2021 Invasion Day rally people in the streets could not hear because buildings blocked the sound. This is why we need a public address system with horn speakers distributed amongst the crowd. Photos below show Queens Park when full and demonstrate the difficulty of delivering sound to the entire crowd.

23. Cost of Hire

We are not for profit and try to keep costs down. We will be consulting people about the cost of the various systems. We take into account the cost of maintenance of the system and what organisations are able to pay. If we provide a person to bring the equipment and assist at a rally some added expense may be incurred.

24. AppendixTechnical manual for Chiayo PA system

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