FREQUENTLY ASKED QUESTIONS

Q. What is BMR?
A. BMR stands for Balanced Mode Radiator, which is a single loudspeaker that delivers full-range audio output.

Q. What is Cotswold Sound
A. Cotswold Sound (CS) is a company set up by Jon Vizor to design, manufacture and distribute BMR drive units to hi-fi loudspeaker manufacturers.

Q. Does the BMR system use the same technology as HiWave's SurfaceSound?
A. No. The invention of BMR has its own distinct technology, and Intellectual Property.

Q. How is the low frequency produced?
A. At low frequencies the unit has essentially identical performance to a conventional bass unit and operates in the same way.

Q. What is the bandwidth limit of BMR technology?
A. The limits of bandwidth are determined by the number of modes balanced. This balancing action allows the very high frequencies to be accurately reproduced.

Q. What are the limitations of the new BMR system in terms of size?
A. The BMR solution works for all simple diaphragm and chassis shapes currently employed in the audio industry. For the moment our development has focused on mid-sized drive units. A unit developed at the technology centre, with an 85mm diameter panel, is currently being evaluated or used by a number of customers. Larger units have been designed and made, and smaller units, such as the 2.5 inch are already in mass production and feature in a number of systems currently on the market.

Q. Does BMR technology give loudspeaker manufacturers the opportunity to achieve further cost savings?
A. The action of balancing the modes in a circular BMR is achieved by adding masses to the panel, lowering sensitivity. This can be offset to some extent by eliminating the need for a separate treble unit and associated crossover, making the overall manufactured cost of BMR drivers similar to conventional units. However, there is likely to be a need for some passive filtering, especially for BMRs designed for use in an enclosure. This filtering will be less important in cases where the BMR is fitted into a wall or ceiling (custom installed).

Q. Does BMR technology completely eliminate the use of a crossover?
A. Since the BMR is a single unit, no crossover is needed, but a mild shelving filter could be used.

Q. If the BMR system utilises a piston system for its extended bass response, does that mean that slim designs are still possible?
A. Yes, because its diaphragm is planar, a BMR driver's overall depth is significantly reduced compared to that of a conventional cone unit.