The CFH 400 Coaxial Horn Loudspeaker Project.

The CFH 400 project began in 1995. The original coaxial horn design was the brain child of Paul Johansen who was helped by Tom Cochrane and Graham Bowers who at the time were working for Axent Audio Ltd in New Lynn. The product  would not have seen the light of day without the mathemetical input of Tom who calculated the flare shape. Graham and Kelly Waterman's willing support meant that accurate testing could be done in their modern accoustic chamber using their Hewlett Packard test rig.
This was indeed an exciting project and the final performance of the prototype exceeded all our expectations. The sound was very forward and transparent and it did not have the typical nasal quality normally associated with horn speakers. This in itself was a huge bonus and quite unexpected.
Since the products inception 24 pairs have been sold and 8 units proudly form the mid high section of Stage Sounds 3 Way  30,000 Watt A Rig.  A search by solicitors AJ Park and Son proved that his product could have sustained a world wide patent because of the unique way the aluminium phase plug was used to combine  the twelve inch mid component with the one inch high frequency compression driver.
Like so many other great NZ products its development has stalled, primarily due to NZs isolation from the international market place. In 2003 we had the opportunity of demonstrating it to John Lee, the major shareholder of Tom Lees Music in Hong Kong. This gentleman owns a chain of 17 music stores and a large PA company in Hong Kong. He also owns Canadas largest MI importing company. This seemed to us like a very good break.
John Lee was so impressed with our CFH400 loudspeaker that he asked me if he could take a pair back to Hong Kong. We entered the usual negotiations and as fate would have it the whole idea bogged down in red tape. John  withdrew  his offer to cover the patent costs because I could not guarantee him a world wide patent cover due to the unfortunate fact that I had already sold some. We could have, as it turned out, patented the product  in China and the USA. However this was apparently not sufficient  for John?s company to commit to backing the project.

Installations To Date:

The first user was a substancial church group in Glenfield and they have been in use in this church since 1995 with total reliability and their client has been very pleased with their performance.

The second major install was for Kristin Schools auditorium which we believe is the largest private school auditoium in NZ. They use 6 units in their very large auditoium.

A major Auckland nightclub was fitted out with two pairs in 2002 for use over a very reverberant dance floor and the results proved their ability to reduce reverberation successfully.

Three state schools have used them for assembly hall applications and we have been able to achieve 10 words out of 10 at the rear of an empty hall. This is very hard to achieve without horn loading throughout the vocal range of the audio spectrum.

Whangaporoa College as a central vocal speaker in their superb new theatre auditorium.

Stage Sound Ent Ltd have eight CFH400 coaxial horns in current use in their A rig which has received much critical aclaim for its clarity and projection.

Specifications:
Sensitivity                           106 db per watt meter.
Frequency response           180hz to 18khz +- 3 db.
Directivity                           60 degrees x 40 degrees
Cross over frequency         180 Hz and 2.3khz.
Power handling.                 1000 watts AES
Impedance                         8 ohms.
Components                      1 inch B and C DE25 driver with 60x40 flare and 12 inch B and C PE-32.

Price guide $2000+GST per unit. Manufactured in NZ by: Stage Sound Ent Ltd  Ph: 0649 444 8776

Latest Developments.

A new recently prototyped new version using a plywood sleeve to house two units is being trialed by Stage Sound in situ in a large theatre auditorium. The concept extends the bass responce down to 100Hz by increasing the low mid efficiency. This is designed to greatly improve the systems versatility making it more suitable as a full range speech speaker and also improving the products appearance. The objective being a point source vocal loudspeaker enclosure suitable as a self contained central cluster in halls and auditoriums that are highly reverberant when empty or partially seated. We are aiming for an ex manufactures price of approximatly $4000.

Preliminary Spec:

Frequency response: 100hz to 18Khz flat within +- 6 Db.

Power capacity: 1000 wrms or better. 3000 watts AES music power.                               

Sensitivity: 106 Db per watt meter.Coverage dispertion:

100 degrees x 40 degrees.                                   

Impedance: Bi amped only. Four ohms.

Crossover frequency: 2.3Khz @ 18Db per octave or better.

This picture shows four CFH 400 horns prior to final assembly.

 2 x CFH400 coaxial horns in sleeves sitting on W bins.

A frontal view showing the unique coaxial construction.

This system was patentable but we missed the boat and sold to many!