Meeting Topic: Bi-Montly General Meeting
Moderator Name: Adeoye Oyerinde
Speaker Name: Mr. Olagoke Olowofoyeku, Mr. Olayinka Adekanye,
Meeting Location: GiG House 15, Adeniji Street, Ogba Ikeja lagos Nigeria
Lectures were delivered to members on these following topics
LOUDSPEAKER SELECTION AND PLACEMENT
Step i: QUESTIONS OR CONSIDERATIONS
• WHY DO I NEED LOUDSPEAKER?
• WHERE DO I NEED LOUDSPEAKER venue (open space closed space) (stadium, political party campaign ground, studio, show room, cinema house, airport, a typical auditorium, conference room, Lecture hall etc.) (size, shape and general acoustic characteristic of the space)? Have an estimate of number of people in the venue (talking about shape, is it rectangular, trapezoidal, L-shape, Stadium shape etc.).
• WHAT WILL BE THE PROGRAM MATERIAL speech or music or both, what kind of music, classical or contemporary or rock perhaps our fuji or juju etc. The program material will inform you of the frequency response and the average and maximum spl needed
• WHAT KIND OF LOUDSPEAKERS DO I NEED Front loudspeaker or surround or distributed system? (FOH)point source, line source, if it surrounds (bipolar, dipole)5.1, 6.1, 7.1 etc.
Step ii: Studio far field & near field).
DESIGNS:
COVERAGE PATTERN:
LOUDSPEAKER PLACEMENT
CONSIDERATIONS/GUIDING RULES
Placement of speakers within a room is crucial. Your aim is to distribute sound evenly and sonically. that all listening areas of the room have sufficient, intelligible and equal audio coverage.
We must understand that loudspeaker placement is subjective. There is no hard rule that say you must place it this way or that way.
Rule#1: LOUDSPEAKER/LISTENING POSITION RELATIONSHIP
Position the loudspeakers so that the sound from each meets at a shared focal point (SWEET SPOT). Place each loudspeaker the correct distance from the other. The general rule of thumb is follow a triangular pattern (Isosceles or symmetrical). Ensure that the entire loudspeaker setup is centered to avoid phase cancellation.
Rule #2: THE NEARER THE LOUDSPEAKERS ARE TO WALLS AND CORNERS, THE LOUDER THE BASS Loudspeakers placed close to walls will exhibit a reinforcement in the bass (called? room gain?), making the musical presentation sound weightier. Improper placement can cause frequency-response irregularities that color the bass. That is, some frequencies are boosted relative to others, making the bass reproduction less accurate.
Rule #3: THE LOUDSPEAKER AND LISTENER POSITIONS IN THE ROOM AFFECT THE AUDIBILITY OF ROOM RESONANT MODES.
Room resonant modes are reinforcements and cancellations at certain frequencies that create peaks and dips in the frequency response, which can add an unnatural boominess to the sound. When room resonant modes are less audible, the bass is better defined, and midrange clarity increases.
Rule #4: THE FARTHER OUT INTO THE ROOM THE LOUDSPEAKERS ARE, THE BETTER THE SOUNDSTAGING?PARTICULARLY DEPTH.
Generally, the farther away from the rear wall the loudspeakers are, the deeper the soundstage. A deep, expansive soundstage is rarely developed with the loudspeakers near the rear wall. Pulling the loudspeakers out a few feet can make the difference between poor and spectacular sound staging.
Rule #5: LISTENING HEIGHT AFFECTS TONAL BALANCE.
Most loudspeakers exhibit changes in frequency response with changes in listening height. These changes affect the midrange and treble, not the bass balance. Typically, the loudspeaker will be brightest (i.e., have the most treble) when your ears are at the same height as the tweeters, or on the tweeter axis. Most tweeters are positioned between 32? and 40? from the floor to coincide with typical listening heights
LECTURE 2 The Basics of Gain Structure
Introduction: In the circumstances where equipment has some essential properties, like noise, gain, and maximum signal levels and several gears are combined together into a system, disparities in these aspects can sometimes lead to disappointing performance, such as extreme noise or signal overload in one or more components therefore there is need for gain structure.
GAIN STRUCTURE IN SIMPLICITY
The idea of gain structure is that, at each connection between gears in the system (e.g. signal source ? console ? processors ? amplifier) the signal level should be as high as it can be (to minimize noise), but no higher than the maximum level that either component allows to avoid distortion.
• Red signal meter is too high and will cause distortion.
• Yellow signal meter is too low and the lower signals in the music are below the noise floor.
• Green meter is "just right" and represents the ideal music signal level at that connection point.
• DIGITAL WORLD - dBFS: This is linear digital measurement in nature and it start from 0dB downward and anything above this is clipping. Anywhere below the digital ceiling your signal remains the same.
• ANALOG WORLD - dBvu: This is an analog measurement and it can be calibrated however you want it. It can be positive (+) or negative (-) voltage.
• Final Results
The moment the proper gain structure is followed, your loudspeaker should reproduce clean and clear audio with all frequencies in good balancing and no gear will be damaged due to overload.
INTERACTIVE SESSION
The members had an interesting interactive session deliberating on:
Analogue to Digital Transition — is it a curse or a blessing to Audio production industry?
Introduction- Analogue Vs Digital
This interactive session will focus mainly on the issues emanating from the development and deployment of digital technology into the audio production industry.
However, it's important to understand the difference btw analogue and digital recording formals before we get started.
Analogue means the representation of continuous changes that relates to another that has a continuous change
I.e. a recording of continuous changes of an audio waveform
Digital in terms of audio is a sound wave information that is converted into binary code made up of one and zero.
That means digital audio is simply sound converted into digital format.
Sound can be recorded and stored and played using either analogue or digital technologies. Both techniques present series of advantages and disadvantages and these can be analytically and critically compared.
The audio industry has been revolutionized with the advent of digital technology and the resultant growth of practitioner's interest toward digital technology cannot be argued
The question now is with this transition from analogue to digital technology is the audio industry blessed or cursed.
1. Sound Quality Production
2. Audio Production Equipment Configuration
3. Cost of Audio Production Equipment
4. Ease of Equipment
There was series of opinions as to whether the emergence of digital technology into the Audio Industry was indeed a curse or a blessing. It was an interesting interactive session as everyone holds onto their believe on the topic.
Written By: Stephen Aluko
