Twincam Posted October 8, 2014 Share Posted October 8, 2014 Just a thought but wouldn't field coil speakers be lighter weight and cheap to make and just as powerful as permanent magnet speakers. I know some high end audio companies still make them. And there very expensive. But a small magnet and wire would cost alot less than a large magnet especial a neo one. Im pretty sure they could be made cheaply, in the far east they will make anything cheap in bulk. Quote Link to comment Share on other sites More sharing options...
brensabre79 Posted October 8, 2014 Share Posted October 8, 2014 (edited) nice idea i don't think they'll ever be cheaper than fixed magnet drivers though, simply because they are a more complicated design. And i don't believe they'll sound [i]that[/i] much better than modern Alnico or Neo's - which they might be a similar cost to if mass produced. plus they'll need a DC power supply (hundreds of volts) and some way of dissipating the heat maybe good for audiophile hi-fi stuff, but i don't think they'll make for a good portable bass cab Edited October 8, 2014 by brensabre79 Quote Link to comment Share on other sites More sharing options...
bertbass Posted October 8, 2014 Share Posted October 8, 2014 When I were a lad, many years ago, I had an old valve, bakelite radio. Needing a speaker, I took the speaker out of the radio and stuck it in a cabinet. How disappointed was I when it didn't work. It turned out to be one of them thar speakers, but I had never heard of them at the time. Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted October 8, 2014 Share Posted October 8, 2014 Ah those were the days. My addiction to speakers started with a field wound speaker in my old radiogram (You'll have to google that young people) My parents were out so I resoldered the coil from the 110V tap on the mains transformer to the 240V mains. It hummed quite a bit but boy was it loud, so loud I just had to carry it out of the house and down the bottom of the garden to see how far away it could be heard. Biggin Hill about 4 miles away apparently. Very satisfying, and I managed to get my dad's soldering iron and Avometer back undiscovered before anyone got home. Cracking afternoon that. The trouble is the coil was heavier than any magnet and made of very expensive copper. Cheaper to use neodymium and lighter to use ceramic. Even if you did a Clarkson and applied a million volts the pole piece would saturate and there'd be no increase in power. Are people still making them? Wow! Quote Link to comment Share on other sites More sharing options...
dincz Posted October 8, 2014 Share Posted October 8, 2014 Nothing to add really, but wasn't it common to use the field coil as a power supply filter choke? Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted October 8, 2014 Share Posted October 8, 2014 [quote name='Twincam' timestamp='1412770668' post='2571799'] Just a thought but wouldn't field coil speakers be lighter weight and cheap to make and just as powerful as permanent magnet speakers. [/quote]They're more expensive, and overall heavier, as they require a power source. That's why they were replaced by permanent magnets. Quote Link to comment Share on other sites More sharing options...
Twincam Posted October 8, 2014 Author Share Posted October 8, 2014 Im convinced with modern tech they can be made cheap. If in bulk!. I read something as well on some forum a manufacture of speakers and cabs in eastern europe calculated they could be made cheap. But i can't find where i read that now. Also looking at the design itself there's really nothing special about them very simple really. However if im wrong on the weight and them being manufactured cheap i believe there is one very interesting thing that would get a lot of peoples attention is that the speakers are tuneable on the fly to a degree. Surely that would be worth a fair amount of attention. As for the power source a smart move would be to have power from a custom amp head, which would add little to a head. If i was going to come into amp and cab manufacture this is how i would go. Anyhow like i say just my mind making random thoughts. Oh yeah i hadn't heard of field coil speakers i actually thought i invented them till i looked them up. Mine were called electromagnetic speakers haha. I just thought hey why don't speakers have a powered electromagnet on them. Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted October 8, 2014 Share Posted October 8, 2014 [quote name='Twincam' timestamp='1412795121' post='2572208'] As for the power source a smart move would be to have power from a custom amp head, which would add little to a head. [/quote]The power supply would have to be in the speaker, otherwise you couldn't use them with anything but a dedicated amp. They have their fans, but mainly they're cut from the same cloth as those who yearn for the halcyon days of AM radios and the Model T. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted October 8, 2014 Share Posted October 8, 2014 [quote name='Bill Fitzmaurice' timestamp='1412797992' post='2572245'] The power supply would have to be in the speaker, otherwise you couldn't use them with anything but a dedicated amp. They have their fans, but mainly they're cut from the same cloth as those who yearn for the halcyon days of AM radios and the Model T. [/quote] One needs long-wave AM to pick up the BBC here in France. Old technologies have their 'niche' advantages (sometimes...). Just sayin'. Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted October 8, 2014 Share Posted October 8, 2014 [quote name='Twincam' timestamp='1412795121' post='2572208'] is that the speakers are tuneable on the fly to a degree. Surely that would be worth a fair amount of attention. [/quote] how's that a positive? build a bass reflex cab... tune it.... and then have a driver you can change the tuning on? telescopic port tubes may be easier Quote Link to comment Share on other sites More sharing options...
Beer of the Bass Posted October 8, 2014 Share Posted October 8, 2014 Hmm, I like the idea of a field coil speaker with it's own switch-mode power supply. It reminds me of the people who were experimenting with 3D printing 12" LPs! Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted October 8, 2014 Share Posted October 8, 2014 [quote name='Dad3353' timestamp='1412798455' post='2572249'] One needs long-wave AM to pick up the BBC here in France. Old technologies have their 'niche' advantages (sometimes...). Just sayin'. [/quote]I can get anything anywhere in North America with satellite radio. Just sayin'. Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted October 9, 2014 Share Posted October 9, 2014 [quote name='Bill Fitzmaurice' timestamp='1412808430' post='2572400'] I can get anything anywhere in North America with satellite radio. Just sayin'. [/quote] I was in America last month, was mental, the FM radio on the hire car needed retuning every 5 miles. At one point We were driving through Shenandoah on the skyline drive and on the Richmond Side we got some rock station and the moment the road turned to the Shenandoah Valley side of the hill it was some christian praise station.... mental Quote Link to comment Share on other sites More sharing options...
Phil Starr Posted October 9, 2014 Share Posted October 9, 2014 (edited) [quote name='Twincam' timestamp='1412795121' post='2572208'] Im convinced with modern tech they can be made cheap. If in bulk!. However if im wrong on the weight and them being manufactured cheap i believe there is one very interesting thing that would get a lot of peoples attention is that the speakers are tuneable on the fly to a degree. Surely that would be worth a fair amount of attention. As for the power source a smart move would be to have power from a custom amp head, which would add little to a head. If i was going to come into amp and cab manufacture this is how i would go. [/quote] They can't be made cheaper as you have a massive copper coil, copper prices are rising steadily, one of the drivers to switch mode power supplies. However you streamline your manufacturing you can't affect world copper prices. Also not tunable as the only thing you can change is the magnet, Make it more powerful and you change the electrical characteristics of the speaker which mean redesigning the cabinet. In any case if you knew 100V was the optimum voltage for a particular speaker design why would you turn it to 80V to degrade the speaker? These things were made when magnets were made of materials that lost their power over time and copper was relatively cheaper. I'm sure there is a market for steam engines and typewriters and Ferguson tractors and I love all that sort of thing but the idea that this is a better technology rather than a curiosity doesn't really hold much water. Edited October 9, 2014 by Phil Starr Quote Link to comment Share on other sites More sharing options...
Twincam Posted October 9, 2014 Author Share Posted October 9, 2014 Ok all pretty good points. I still think the idea is cool though. They are supposed to be very efficient, very loud per watt. You get a few extra db from from. Quote Link to comment Share on other sites More sharing options...
Dad3353 Posted October 9, 2014 Share Posted October 9, 2014 [quote name='Bill Fitzmaurice' timestamp='1412808430' post='2572400'] I can get anything anywhere in North America with satellite radio. Just sayin'. [/quote] BBC Radio 4..? [size=4] [/size][size=4] World Service, yes, but Radio 4..? Which satellite covers that for USA (Astra 2b is pan-European...)..? Genuine question.[/size] Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted October 9, 2014 Share Posted October 9, 2014 [quote name='LukeFRC' timestamp='1412836740' post='2572453'] I was in America last month, was mental, the FM radio on the hire car needed retuning every 5 miles. At one point We were driving through Shenandoah on the skyline drive and on the Richmond Side we got some rock station and the moment the road turned to the Shenandoah Valley side of the hill it was some christian praise station.... mental [/quote]That's because FM is a line of sight transmission medium. So is satellite for that matter, but whereas with FM line of sight could be as little as ten miles to a two hundred foot tall tower, with satellite it's to a point some 42,000km high in the sky. [quote]They are supposed to be very efficient, very loud per watt. You get a few extra db [/quote] Feld coil drivers have no higher sensitivity than PM drivers. Sensitivity is determined by T/S specs, not the magnet composition. Quote Link to comment Share on other sites More sharing options...
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