Check out the resources below for explanations on audio topics.
When in a large venue, there are speaker stacks part way through the space to reinforce the sound coming from the stage because otherwise, the back of the audience wouldn’t be able to hear the people on stage well enough. These delay stacks must be set to output the audio information at the right timing so the reinforcing speakers don’t produce the audio before the time it takes for the wave–front coming from the stage to arrive. This is because sound through air takes much longer to travel than the electrical signal coming from the sound board to the speakers and all the speakers will receive the electrical signal simultaneously.
By delaying the reinforcing speakers the correct amount of time, the audience will hear the sound from the stage with the reinforcing speakers. After calculating the time it will take between the speakers and setting the delay timing accordingly, play with adjusting the delay timing further within the Haas effect range.
If the reinforcing speakers were left at the pure calculation of the time it takes between speakers, the reinforcing speakers could overpower the sound coming from the stage and would create an unnatural perception for the audience seeing the musicians but hearing them as coming from the reinforcing speakers. By adding a delay amount within the Haas zone, we can use the precedence effect. Then the audience will perceive the sound’s direction as coming from the stage since the stage’s wave–front will arrive before the reinforcing speakers’ wave–front — as long as the volume from the reinforcing speakers isn’t overpowering the first wave–front.
AcoustiTools® can tag the front main speakers and tag a delay stack to quickly calculate the delay timing. No longer do you have to manually use a tape measure and then plug the measurement into a math formula to calculate the result yourself. AcoustiTools does this for you.
Simply put, a mode is a frequency that will resonate in a room based on the dimensions of a room. One of the main aspects of modes to be avoided are wide frequency gaps between each mode. If the modes are equally spaced, they will not be noticeable, but if there are gaps between the modes, they will be quite audible and will need treatment.
Nodes are the cancelation points in a room where sound waves collide out of phase and cancel each other out, creating null points in the room for that frequency. Nodes and Antinodes must be avoided at the listening position.
Antinodes are the buildup points in a room where sound waves combine in phase and create peaks of the frequency in different positions in the room. Nodes and Antinodes must be avoided at the listening position.
Spectrum Block Size is the value that determines how large of a buffer builds up before being processed. The larger the buffer, the more accurate the values will be. However, the larger the buffer, the more the device has to work. If you experience trouble processing on your device, try decreasing the Spectrum Block Size. AcoustiTools® defaults to 4096 because it returns values rapidly while still giving detailed results.
For Spectral Weighting, you can choose between A, B, C, or Flat.
A-Weighting is typically used because it has a frequency response curve that is most like the human ear at most volumes — dropping off in sensitivity as the frequencies get lower.
B and C are increasingly more linear than A — following how the human ear gets more linear at louder volumes. These are intended for increasingly loud sound pressure levels and checking low-end levels that are rolled off in the A–weighting.
Flat has no filtering and can check how the sound levels are at all frequencies as the microphone “hears” it.
When a frequency is building up in a venue and overpowering the rest of the audio or is threatening feedback, you can use an RTA/FFT (Real Time Analysis / Fast Fourier Transform) to get visual feedback of frequency volumes in an x/y graph showing frequencies vs. decibels. This helps confirm which frequencies are problematic so you can make the appropriate adjustments with confidence. AcoustiTools’® RTA/FFT module gives you control over spectral weighting, spectrum block size, and more to help your diagnostics!
The RTA/FFT module is also useful when setting up to check the response of your speakers in the venue. By sending pink noise through the system and watching for exaggerated frequencies in the metering, you will be aware of possible problematic frequencies before practice.
It is important to monitor the average decibel (dB) values during an event to protect your audience’s hearing as well as your own. AcoustiTools® continuously displays these values.
Knowing the peak of your system’s audio output is important to avoid overheating your equipment or blowing out your speakers. AcoustiTools® provides this information in both the dB Meter and the Spatial modes.
AcoustiTools’® Spatial module uses depth sensing, motion-tracking and area-learning (enabled by platforms such as ARKit) so you can easily tag your speakers and multiple points in the audience during an event’s set-up or practice so you can know the sound pressure levels throughout the venue from the FOH (Front Of House) position. When doing live sound in a venue such as a theater, concert hall, or even a conference, you don’t have the luxury during the event to check sound levels throughout the audience seating. Imagine walking down an isle in front of audience members with your dB meter! Unless you have memorized the difference between the volume at the FOH position vs. the multiple points in a venue where your speakers are and your audience is seated, you are stuck with educated guesses. AcoustiTools easily solves this problem.