You'd be unlikely to bother, because they're not working the same way. The Voigt pipe (ML-horn) you picture is a standing-wave generator. It's not impedance-matched over any part of its usable operating bandwidth and is simply employing resonant action: by design you don't want to be limiting that internally except by damping as it's essentially their raison d'etre.
FWIW, I much prefer Thuras's patent driver-in-vent and its multiple vent 'ring' variant reflex system that can achieve essentially the same response in a much simpler, cheaper design without the additional impedance, phasing issues: US1869178A - Sound translating device
- Google Patents
- Google Patents