I want to mention some old loudspeakers I've come across or heard about. Maybe some equally vintage Forum members will be able to add more information.
1. I was a regular user of Hamrad in Cape Town in the early 60's and their catalogue carried a wonderful array of electronic items, including a loudspeaker known as the Ionophone. This was a form of plasma speaker and in searching on this, I found the following website, which is a mine of information about this fascinating loudspeaker: www.roger-russell.com. This is well worth reading, also to discover how old the idea is.
Anyone out there ever come across this is real life?
2. In later years, Hamrad stocked Goodmans loudspeaker. There was a design, either a Goodman or a clone type, that used a vertical curtain of sound absorbing material e.g. underfelt inside the cabinet with the back panel full of holes. The holes looked like airholes in a box and would have added up to a reasonable diameter port but without a tuning tube. So a distributed port if you like. This could have been a cross between a bass reflex and open back speaker.
Anybody ever come across one of these
3. I found at an auction once, a Yamaha panel speaker, made of cast metal, possibly zinc alloy, that used polystyrene panels, surfaced with a shiny black plastic skin. The panel was about 60 by 40 cm. The panel was divided into two, possibly three sections, of different sizes and shapes. The main 'woofer' section resembled the shape of an ear, more or less, if I remember correctly. The skin had delaminated in places and formed blisters against the polystyrene. The skin buzzed when the speaker was hooked up to a source and unfortunately, I couldn't repair it.
I read somewhere that that speaker was used in an organ.
Anyone know anything about this?
4. I worked on Saturdays at a shop in Cape Town that stocked Philips sound gear. Some of the Philips stuff was quite good and I got hold of a loudspeaker driver catalogue from Philips. In it I found a fascinating speaker. It had a sensing element mounted on the cone, I think, that generated a current with cone movement. This current was fed into a comparator circuit, which compared the input signal with cone displacement and applied a correcting current to the voice coil, which would then align the cone with its ideal position relative to voice coil signal.
I don't think this ever caught on commercially but is similar to the idea used by Devialet in their SAM loudspeaker electronic modules. The Devialet model of course applies a pre-measured set of adjustment signals to adjust the loudspeaker cone into the ideal position relative to input signals. The sound quality difference is, I have read, substantial.
Has anyone come across this Philips speaker?
1. I was a regular user of Hamrad in Cape Town in the early 60's and their catalogue carried a wonderful array of electronic items, including a loudspeaker known as the Ionophone. This was a form of plasma speaker and in searching on this, I found the following website, which is a mine of information about this fascinating loudspeaker: www.roger-russell.com. This is well worth reading, also to discover how old the idea is.
Anyone out there ever come across this is real life?
2. In later years, Hamrad stocked Goodmans loudspeaker. There was a design, either a Goodman or a clone type, that used a vertical curtain of sound absorbing material e.g. underfelt inside the cabinet with the back panel full of holes. The holes looked like airholes in a box and would have added up to a reasonable diameter port but without a tuning tube. So a distributed port if you like. This could have been a cross between a bass reflex and open back speaker.
Anybody ever come across one of these
3. I found at an auction once, a Yamaha panel speaker, made of cast metal, possibly zinc alloy, that used polystyrene panels, surfaced with a shiny black plastic skin. The panel was about 60 by 40 cm. The panel was divided into two, possibly three sections, of different sizes and shapes. The main 'woofer' section resembled the shape of an ear, more or less, if I remember correctly. The skin had delaminated in places and formed blisters against the polystyrene. The skin buzzed when the speaker was hooked up to a source and unfortunately, I couldn't repair it.
I read somewhere that that speaker was used in an organ.
Anyone know anything about this?
4. I worked on Saturdays at a shop in Cape Town that stocked Philips sound gear. Some of the Philips stuff was quite good and I got hold of a loudspeaker driver catalogue from Philips. In it I found a fascinating speaker. It had a sensing element mounted on the cone, I think, that generated a current with cone movement. This current was fed into a comparator circuit, which compared the input signal with cone displacement and applied a correcting current to the voice coil, which would then align the cone with its ideal position relative to voice coil signal.
I don't think this ever caught on commercially but is similar to the idea used by Devialet in their SAM loudspeaker electronic modules. The Devialet model of course applies a pre-measured set of adjustment signals to adjust the loudspeaker cone into the ideal position relative to input signals. The sound quality difference is, I have read, substantial.
Has anyone come across this Philips speaker?
