 1970's CORAL beta loudspeakers |
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My favourite loudspeakers by far! I will always own these Coral horns. Superb open sound with real zest and detail. The cones are well protected by a pair of Yamaha steel mesh grilles. Those used to protect the NS1000-M's famous JA-3085 drivers. The back loaded horn cabinets (BL-25D) were built by Kevin Kuscoff (Trimax Cabinets) during May-June 2003. A high grade marine ply was used. The cabinets were later stained and finished with Danish Oil The aluminium laminate was added later by the guys at CabTech Some sound absorbing material has been placed in the throat area behind the driver. These speakers will sound very live without this. Experimenting is essential. I ended up using two different materials one natural one man-made. These speakers are very efficient. They have very heavy magnets driving a light cone. 5W should make them go very loud. I am just about to build a pair of single ended mono valves (approx 8W) which should be ideal. How do they sound? Well they vary a great deal depending on what is driving them. With a pair of Quad Twos (GEC KT66) they sound amazingly open and will simply disappear. They are very detailed and engaging but can sound quite thin perhaps a bit bright in the first 5 mins. LEAVE THEM and come back after about an hour. In spite what a lot of people say these speakers are capable of producing great bass. They warm up beautifully, vocals and spatial detail is amazing. The pace and musicality gets so good you will find it difficult pulling yourself away. The vocals (depending on the recording) become very easily fixed along with all the individual instruments. LIKE ANY GREAT SPEAKER You keep coming back for more and they will always surprise you with something extra. The bottom end bass weight can be easily tuned by experimenting with their room location. I find close to corners is best. Quiet amps are essential. Any noise will be greatly exaggerated. A number of owners fit super tweeters to these cabinets. I cannot understand this. To my ears a better option would be to experiment with a high quality sub (operating in a range 20-80Hz) The mid band and HF characteristics are superb
ONE FINE DAY! I rescued these speakers as they were on their way to the tip. The previous owner thought they were too old and ugly. They are in perfect condition. No stains or damage of any kind. Originally in a 5 ported reflex cabinet they are now in new ply horn enclosures. (Plans shown below)
side on with one of my old Quads FINISHING THE SURFACE ADDED MARCH 2004 I decided to stain the enclosures using a diluted Wattyl (Australia) Walnut Stain and varnish. This is a dark stain and I diluted it (about 33%) in mineral turps. The first coat was applied with a standard Bunning's sanding block. I carefully followed the line of the grain. The second coat was rubbed in with a fine steel wool. All oil stained paper and rags should be disposed of carefully. (Fire Risk) After 3-4 days standing, I finished the boxes with a coat of Danish oil. Its important to wipe any excess oil before one hour. This oil seems to dry up within 24 hours. It really enhances the look. Its very easy to use and smells fantastic.
Just built June 2003, BL-25D horn. Many thanks to Kevin Kuscoff
Internal view of a BL-20D horn. Photo by Matthew Gamer, Brisbane
Aluminium laminate added by Cab Tech (Sunshine Coast)
Whata box! They sound a lot better without the mesh but our cat EWOK is very experimental
Right click and save this plan. This picture has good resolution
Fairly ugly original enclosure has good bass. Needs to be off the floor for best results
Matthew Gamer's Beta 8s Here is a rare picture showing a beta 8 alongside my beta 10s. These speakers are owned by Matthew Gamer who lives in the centre of Brisbane. (Matthew like me is a major Coral fan and a complete hifi nut!, Great stuff!) Matthew's speakers are in perfect condition, they have there original boxes and dust covers). Matthew has recently built the original 4 ported enclosure for these drive units. We had a great afternoon comparing the two. Matthew intends to analyse these drive units in detail and will be developing a horn system to match. Keep an eye on this space
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