View VFlex loading
VFlex loading was developed in 2006 by Robert Gaboury for canadian manufacturer Gemme Audio.
This loading technique is different form the traditional bass reflex technique, as it is a Horn / Transmission Line Hybrid. VFlex uses a compression chamber containing a small volume of air and located behind the loaded driver. Sound pressure tends to equilibrate by redistributing pressure in a horn. The horn throat is located at the end of the compression chamber.
As the horn gradually expands, according to a semi-exponential profile, pressure is gradually transformed into velocity. Unlike a horn, the VFlex Horn mouth is enclosed, and a reflector plate focusses moving air towards an acoustic bandpass device of specific geometry. The bandpass device is similar to a port. As the name implies, the bandpass filter’s role is to selectively restrict loading, reinforcing mainly low frequencies.
Research showed that up and over 10 dB of gain was possible with VFlex, and the driver can safely operates well below resonance frequency. VFlex can be succesfully adapted to various drivers of low VAS and low QTS values. The main drawback of the VFlex loading is, like most horns, added complexity and cost.
Because VFlex is intended to work with very “stiff” drivers, as opposed to Reflex loading, a high degree of precision can be achieved. As such, VFlex can be implemented in full range single driver systems or full range 1,5 or 2 way systems. The first commercial design was Gemme Audio Vivace model, based on a single Fostex FE108EZ driver, followed by Gemme Audio Tanto, then, in 2008 by Gemme Audio Katana.