AV #TechTuesday is a WPS-curated column showcasing innovative technologies in the audio-video-lighting industry that we think you'll find interesting. These posts are NOT sponsored.
In a controlled environment like a recording studio, resonance management is incredibly important for engineers that need consistent and accurate sound reproduction and since studio spaces are made with all different types of materials, the rate at which reverberations decay can vary widely. To combat this, engineers employ acoustic treatment to mitigate excessive resonance, but many of these strategies only focus on midrange and high-frequency sound. With no place to go, low frequencies often get “trapped” and can be much more difficult to manage.
Tackling this problem is PSI Audio, a Swiss manufacturer of active studio monitors that recently launched the AVAA C20, an active bass trap that works by acting as a sound pressure sink to absorb low frequencies. The AVAA (Active Velocity Acoustic Absorber) has been in development since 2012 when PSI partnered with two Swiss universities and their electronic and electroacoustic engineers to refine the proof-of-concepts from PSI’s extensive experience in recording studios.
HOW IT WORKS
First and foremost, the AVAA is not a noise-canceling speaker and does not alter the sound of the source. Instead, the AVAA works by measuring the acoustic pressure in front of an acoustic resistance. The acoustic resistance allows the air to pass through but reduces the pressure significantly. A transducer behind the acoustic resistance absorbs the volume of air going through the acoustic resistance and ensures a specific acoustic impedance in front of the acoustic resistance. This creates an acoustic impedance in front of the acoustic resistance that is significantly lower than the ambient air and works as a pressure sink. The acoustic impedance affects a radius of 3.3’ft. to ~5’ft. or 1 meter to 1.5 meters around the AVAA.
The AVAA absorbs standing waves between 15 and 150Hz in a room and is significantly more efficient than passive absorbers measuring many times the size of the AVAA. PSI claims that the AVAA has the same effect on frequencies from 15 to 150Hz as opening a window about 5 to 20 times the size of the AVAA.
This efficient performance helps reduce reverberation decay in this frequency range even further and prevents the bass from masking higher frequencies allowing for clearer details in those high frequencies.
OPERATION AND PLACEMENT
PSI has designed the AVAA to be as close to a plug-and-play solution as possible with no calibration or setting configuration required and because it’s analog, the AVAA does not need a DSP to function.
Since every space has different room modes based on construction material, wall placement, and wall shape, PSI recommends testing the effectiveness of the AVAA by first placing the units in the corners behind the source speakers and comparing the frequency delays in the listening position. Placing the AVAA in the corners or against hard (concrete) walls will be more effective.
PSI recommended two to four AVAA for medium-sized rooms between 65 sq. ft. and 262 sq. ft. For larger rooms, it is recommended to consult an acoustician to identify the highest pressure zones for each room mode and use the map to highlight the areas that are contributing to each disturbing room mode.
Why you should care:
- Plug-and-play operation. Requires no DSP to function and operates with zero latency
- Acts as a sound pressure sink to absorb standing waves in a room between 15Hz and 15Hz
- Has the same effect on lower frequencies as opening a window 5 to 20 times the size of the AVAA
- Designed for medium-sized rooms between 65 sq. ft. and 262 sq. ft.
- Generates an impedance effect with a radius of 3.3’ft. to ~5’ft.
- Emits no sound – the AVAA is not a noise-canceling speaker
If you have any questions on the AVAA or would like to learn more about acoustic treatment and frequency management for your studio, send us a message below: