08-03-2018, 03:45 PM
So it is just a new fangled way of saying column speaker!
Mike
Mike
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Schuchhardt microphone
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Mike, as I said in post #6, "I'm thinking here of the way line source speaker - aka column speakers - focus the sound coverage in the vertical plane whilst giving a wide dispersal action in the horizontal plane (with the column mounted vertically as usually found)."
 As for being a 'new fangled'' term, I've been familiar with it for the best part of 60 years - how far back do you consider something to be 'new'? 
16-03-2018, 12:34 PM
(08-03-2018, 05:00 PM)Terry Wrote: Mike, as I said in post #6, "I'm thinking here of the way line source speaker - aka column speakers - focus the sound coverage in the vertical plane whilst giving a wide dispersal action in the horizontal plane (with the column mounted vertically as usually found)." Back in the day, (1950s/60s) when line source speaker columns were becoming popular for PA, there were also column speakers used for domestic hi-fi, with the main speaker unit typically mounted in the top of a pipe. The pipe resonances reinforced the low frequencies and, as long as they were judiciously damped, could give good sound: the Wharfedale concrete 'sewer pipe' design was a well-known example. A 'column' speaker could therefore mean two things, hence the PA variety was preferably called 'line source'. Today, the domestic 'column' has largely disappeared so the confusion doesn't arise. Meanwhile the PA line source has grown into the giant curved linear arrays used at festivals. Martin
BVWS Member
16-03-2018, 03:01 PM
Yes, I remember those well - if memory serves me correctly, the Wharfedale product was inspired by a design in either PW or WW.
It looked something like this (the walls of the concrete pipe should be thicker than they've turned out here, but you get the general idea): The concrete pipe - or a chimney pot was also suggested as an alternative - sat on feet to raise the base from the floor. A small circular baffle with a full range loudspeaker was mounted at the top, facing upwards, and a cone was mounted above it to reflect the high frequencies horizontally. About 2/3 of the way down, a slotted wooden baffle was fitted and the entire pipe was lined with a generous layer of cotton wool or similar, which I haven't tried to portray.
KB's attempt at a column speaker, unfortunately they only used thin 1/8th inch ply for the drum, and drum it can tend to be in the effect on certain resonances, and a flimsy plastic inverted cone at the top. But they do have an interesting effect on the dispersal of the sound, making it more difficult to get an exact location of the sound source. https://www.radiomuseum.org/r/kolsterbr_ks651.html
Anyway I wonder how Dave is getting on with the testing of his microphone? Mike
16-03-2018, 06:20 PM
Those columns are a bit on the short side, aren't they, Mike?
(16-03-2018, 04:04 PM)Crackle Wrote: But they do have an interesting effect on the dispersal of the sound, making it more difficult to get an exact location of the sound source. Interesting. I think it really depends where you put them. If you stand the concrete columns in the room corners - which used to be the favoured position for floor standing cabinets, anyway, the hard walls would very effectively reflect and focus the sound, so I don't see a problem. Pye made a corner situation a virtue with its Black Box hi-fi. The speakers were mounted in the sides of the relatively narrow - not much more than a record player of the period - cabinet with the idea being that it should be placed diagonally in the corner of the room so that the sound was reflected off the walls to create a much wider sound stage. We sold a Hong Kong made pocket transistor radio in the 60s. All of these sets, whether of Japanese or Hong Kong origin were virtually identical electronically and tended to suffer the same problems: battery connector wire pulled off and faulty volume control or the associated switch or, more rarely, detector diode or its load resistor broken due to them being located on the extreme corner of the pcb next to the battery compartment - one whack from the PP3 while fitting it was all it needed! Anyway, I digress. The only thing that differentiated any of these sets was the variety of plastic cases. The speaker on the sets we sold was mounted in a recess, thus it protruded from the front of the cabinet proper by a couple of mm with a gilt ring round the edge raising slightly more. The trick, when any of the sets came into the workshop was to lay the set on its back and place a tube over the speaker - usually a handy copy of a Trader magazine with an elastic band round it to hold it onto the radio. The bass response that these little sets suddenly produced was amazing! I spotted an extension speaker in Woollies one day. It was the usual 3" speaker mounted in the centre of a 3" tube about 10" or so long. I never heard one but I expect it sounded good! |
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