ABH and power law curve in the TL audio duct

Please login with a confirmed email address before reporting spam

Hello everyone, I would like some opinion on the correct physical interpretation of a system that combines an Acoustic Black Hole (ABH) profile, a power-law curve, with a progressively increasing cross-sectional area filled with fiber or foam. I've read about this topic, but I'm not sure if it can also be applied in the audio field to the first part of a transmission line duct (after the woofer and before the 180-degree bend) of a speaker enclosure. I'll briefly summarize what I understand: 1. A duct in which the air cross-sectional area decreases towards the end following a power law (curve with exponent ≥ 2). From theory, this profile should progressively slow the phase velocity of the wave to values ​​close to zero, reducing reflection at the end. 2. In the terminal area of ​​the duct (where the air cross-sectional area is now very small), the space is almost completely filled by a wedge of porous material (fiber) with progressive density (increasing towards the tip). **Note: I thought about applying the power-law curve and the wedge of porous material to opposing panels (one facing the other). I've attached an image.

Does anyone have experience with this? Any explanations are welcome, even simple ones, because I'm still a beginner.

Thanks to anyone who can respond.

References - ABH/SBH theory for ducts: ScienceDirect - A plug-in sonic black hole for duct terminations - Rectangular ABHs for air absorption: ScienceDirect - Numerical study of rectangular acoustic black holes - Distinction of mechanisms in SBH: ScienceDirect - Sonic black holes without rainbow trapping



Reply

Please read the discussion forum rules before posting.

Please log in to post a reply.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.