Concept

This paper describes the design of a continuous-duty Natural Sound Reinforcement System®(NSRS) capable of generating high sound pressure levels from stacked active loudspeakers. It is conceptualised primarily for outdoor use on single or two-tiered Panwagons® (Appendices A & B) with sound being projected from a main array of six loudspeakers located at the back of these vehicles (146 dB @ 1m) and secondary arrays of four loudspeakers on either side (143 dB @ 1m). Provision is also made for the accommodation of four on-board monitor loudspeakers. Their primary purpose is to ensure that players hear each other and remain in synchronization with the rhythm.

With a frequency response of 30 Hz to 16 kHz ± 3 dB and a calculated loss of 34 dB at 50 metres and 40 dB at 100 metres, coupled with 70º horizontal and 60º vertical dispersion, the NSRS® can adequately serve the needs of a large group of masqueraders. It may therefore be used to provide live and pre-recorded steelband music on the road and in fetes. Moreover, the system is modular and components may be added or removed as the need arises.

The design utilises high-intensity, powered omnidirectional microphones (Danish Pro Audio - Appendix C) and active loudspeakers (Meyer Sound - Appendix D) driven from a relatively quiet A.C. generator. It is emphasised that if Pan has to be accepted as a commercial medium for providing music, the sound reinforcement system must be capable of delivering superior quality audio with minimum distortion in order to create the desired impact. Provision is also made for a lead vocalist and/or a DJ to operate via wireless microphones, thus ensuring flexibility of use.

The omnidirectional microphones may be used in conjunction with a digital recorder to produce high quality steelband recordings. The cost of the NSRS® may be amortised over a period of five to seven years. The system may also be used to generate income by leasing or renting it for use in high quality Public Address installations outside of the Carnival season.

The advantages of active loudspeaker systems are:

a) Amplifiers, control electronics and transducers are contained in one compact, portable cabinet;
b) Set-up time, space requirements, transport and labour costs are significantly reduced;
c) Audio performance and reliability are greatly enhanced;
d) The signal path and cabling are simplified thus reducing losses; and
e) Modular construction allows ease of maintenance.

The advantages of powered, high intensity omnidirectional microphones are:

a) Increased head room, wider dynamic range and transformer-less line-level outputs are achievable;
b) Peak levels in excess of 160 dB may be accommodated before clipping occurs;
c) A high degree of spatial resolution is attainable; and
d) Superb transient response and attack time are realisable.

The total on-board load requirement is 152A @ 115V, requiring a power supply of 17.48 kVA capacity. In accordance with good engineering practice, an A.C. generator of 30 kVA capacity is recommended.

Scope

The following applications are envisaged:

a) To amplify live and pre-record steelband music during the Carnival season;
b) To enable arrangers to teach music to large ensembles more efficiently;
c) To enable pannists to listen to steelband music played back at realistic levels so that they can understand the concept of Soundstaging;
d) To be used in Public Address systems for proposed Pan Campuses; and
e) To be rented or leased outside of the Carnival season.

System Components

The system consists of:

a) Four high-quality omnidirectional powered microphones;
b) An active mixing console;
c) A line-level pre-amplifier;
d) Eighteen active loudspeakers;
e) An A.C. generator for the power supply;
f) A professional dual CD console; and
g) On board fluorescent and decorative lighting for night time performances.

General Specifications

a) Powered Microphones shall be:
· Omnidirectional, capable of accepting 160 dB SPL without overload;
· Directional, wireless, hand-held, with 200ft transmitter range; and
· Directional, wireless Lavalier with 200ft transmitter range

b) Active Mixing Console shall be:

· 14 Channel with minimum electronics, preferably built from discrete components.

c) Pre-amplifier shall be:

· Low output impedance with two XLR outputs each capable of driving up to nine powered loudspeakers.

d) Active Loudspeakers shall be:

· Capable of delivering up to 146 dB SPL @ 1 metre when stacked. Weatherproof and designed for continuous duty. Modular construction for ease of maintenance.

e) CD Console shall be:

· Two synchronised machines to enable mixing of music, with a high level of vibration isolation.
f) Generator shall be:

· 30 kVA diesel or gas operated. 115V±6%, 60Hz±2%. Maximum intrinsic acoustic noise level 60 dB @ 1m.

g) Cables and Connectors shall be:

· As necessary for audio and electrical installation.

h) Lighting shall be:

· Six dual 8ft fluorescent lighting fixtures with appropriate ballasts designed for surface mounting. Decorative lighting as deemed necessary.

j) Panwagon® shall be:

· In accordance with the two-tiered St. Thomas model as designed by Rising Stars Steel Orchestra. The costing of Panwagons® is not within the scope of this proposal. The static loading of each individual Panwagon® has not been considered, but will have to take into account the masses of all equipment and personnel on board.

Lighting requirements are for night operation

The table details the maximum current requirements for the system by summing the load in amperes (A) required for its individual components.

Appendix A

THE SANCH PANWAGON®

Appendix C
DPAmicrophones.com
Check here for Type 4004 Omnidiretional microphones and accessories

Appendix D
Meyersound.com

Check here for types MSL-4, 650-P, CQ-1 and UPM-1P powered loudspeaker systems