Protable Pro Sound

Design, Engineer, Supply, installation and commissioning of

outdoor portable sound reinforcement system

at the runway hangers for Air-Force Military based

Riyadh, saudi arabia

INTRODUCTION

Name of employer: Matbouli Sound and Communication, Riyadh, Saudi Arabia
Duration of project: from June 2000 till August 2000
Job Title: Technical Sales Engineer

BACKROUND

Riyadh Air-Base, Saudi Arabia is one of the most important American bases in the region due to the strategic location, founded and located in King Abu-AlSaoud road, Riyadh, has a yearly show (dated on 12th of August) on the event of inauguration of the base unit. His highness, Minister of Defense, attends a huge ceremony, where jet-fighters demonstrate some life air show and on-land line for soldiers. Key objective for the air base is to supply a professional outdoor sound system that can:

Covers area of one square kilometer, accounting into consideration the total sound pressure level for jet fighter noise that will be in action during the announcement of line orders.

Portable / detachable, that is to say, speakers can be easily dismantled, with plug and play sockets instead of soldered cables, complying connectivity codes, while the heart of the system including amplifiers and processors are installed in a special arranged van with plug accommodating all kind of light-current signals connected to the installed speakers. The truck also is equipped with UPS, and batteries, to operate in case of mains power failure. All sound equipment is to be properly installed in a standard well vented 19 inch rack inside the van.

My job was to design the system in co-ordination with the acoustics engineer to offer a technical / financial competitive solution and follow-up for the delivery including installation, commissioning, and training for the proposed system. Specifically, I was responsible for reporting day-to-day work progress in accordance to the project timetable to deliver the system on time before the client event. Solving minor technical issues, and coordinating with the client to facilitate all supplies, requests, to my company work team. The project team consisted of 3 permanent technicians, who were responsible for commissioning the sound system rack in the van, whilst outsourcing the cable conduits installation team. I reported to the project manager, in coordination with the acoustic engineer. All financial cash flow for daily activity was my responsibility.

PERSONAL ENGINEERING ACTIVITY

The runway area required to be covered with the speakers was huge, the wind velocity is high, and the noise level is high as well as. I agreed with the client that the seating audience to be under a steel structure umbrella facing the runway. It was around 40 meters by 200 meters. This area is where all the cabling, under structure speakers (to serve the audience), and outside structure speakers (to serve the line show at the runway). Client accepted to use metal ducts for cable pulling and installation. To comply with military specifications (MIL-STD) I used in the project special fire resistant audio, control, RF and electric cables, and special connectors that will connect the van to the cables coming from the steel structure.

To deliver a crystal clear sound system, I chose constant directivity horns; they deliver a perfect frequency response 500 to 18 KHz, and provide highly effective 111dB/W/m sound pressure level, I chose projector type speakers to cover the seating area. I selected two wireless UHF 870MHZ range dynamic microphones with external antenna system. I chose Draka cables for fire resistant cables to serve all the light current and mains’ feed. I submitted a fine tuned system, acoustically designed, and well-engineered.

I prepared a package of excel sheets to track things up. Those excel sheets are: project timeline recording estimated all project activities, proposed date of installations, durations, number of our company personnel on-site, dates for material delivery, source of purchased material (whether it is imported, locally supplied, or manufactured) of the needed devices to achieve that particular day activity. Another excel sheet is project cost, where this file allowed me to compare between budget estimated and actual, in relevance to item by item comparison.

My main daily task was to ensure proper startup for the working team, resolving any contradiction including lack of personnel, while confirming the presence for the next day material and coordinating project daily achievement with the estimated project timeline and reporting to the project manager as well as financial and technical departments. Motion in the military base was restricted, and we needed to finish our job in a quiet, smooth, and professional manner. The client asked us for a weekly forecast to the project actions in advance, while as-done in the previous one. I made sure that to write this report myself.

Follow up for the daily installation progress was one of my favorite activities, like checking the route for installing of the metal conduits, and visual inspection of neat and as per engineering code dictates. I was keen to observe and guide our technical force for following safety guidelines and implementing regulations. For instance, enforcing smoking policy, and proper wearing for the safety dress

While commissioning the system, two major technical problems occurred. The first problem was the UHF wireless microphone transmission was not clear, and there were kind of dead spots in the working area. Firstly, I reconfirmed that the UHF range (870MHz) carrier frequency is not a usable range by any of the communication channels in the airbase. I also tried different wireless microphones with different UHF carrier frequency; they all reacted in the same manner. Secondly, I went on rehearsing the areas where the dead spots were. The dead spots were located randomly in front of the entire four TOA antennas model YW-4500. Although the YW-4500 are indoor type, but they have RF booster, and by changing its value, the reception quality from field wireless microphone got slightly better .So I brought two local TV antenna, with highly directive pattern, and added them to the system, and it fixed the problem.

The second problem was the reverberation time from the smaller projector speakers, model CS304 that we installed serving the seating area. Although the sound engineer studied the sound pressure distribution using “ESAE” program, but it seems that the acoustics was different in an open area environment. I added 2 speakers, redirected 4 speakers, and by trial and error based upon calculating the covered areas of each CS304 speaker, I was able with the help of my technicians to

I believe in customer service to the end. To ensure steady operation during the event, I arranged to attend the event day with the client. That had a great impact to the client, and proved after sales support policy. During the event, a lot of minor tips I delivered to the operator.

Summary

Although my company had a long experience with audio systems, and agents to TOA sound since ages, yet I was able to solve the wireless microphone conflict. It was the first time for me to get exposed to the direct directivity horns, and the sound reproduced from them was amazingly strong, clear and long throw distance. My company honored me for such a prestigious project along with my contributions to solve the conflicts.