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AUDIO FORUMS >> General Discussion and Support >> Field Coils
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Message started by ProggRob on 05/01/16 at 18:38:36

Title: Field Coils
Post by ProggRob on 05/01/16 at 18:38:36

Um, yes please.

http://www.pureaudioproject.com/product/trio15-a5000-field-coil-open-baffle-speakers/

And I was so pleased with my system before I saw these.

Title: Re: Field Coils
Post by beowulf on 05/03/16 at 08:30:02

These look to be super cool! I thought I saw some pricing earlier today, but now it seems to have been removed and while they were not cheap, they seemed pretty reasonable for what you're getting in the package.

The TrioA5000 will debut in Munich High-End 2016. These look pretty promising, using the Wolf von Langa A5000 Field Coil Drivers.

The Trio15 A5000 speakers are a variation of our modular Open Baffle architecture and Leonidas Crossover. They feature four major components:

PureAudioProject Trio15 Open Baffle Platform feat. 15″ Aluminium Frame and Baffles.
4 x OB-A15Neo 15″ Woofers.
2 x A5000 Drivers.
Leonidas Crossover with components for Trio15 A5000.

General Specifications
•SPL: ~96db measured in a typical room
•Frequency Response: 34hz – 20,000Hz (all Trio15 models)
•Impedance: 3.5 to 8ohm
•Amplifier Rated Impedance: 8ohm
•Recommended Amplifiers: 3.5w (Tubes SE) and higher (Tubes, Solid State, Class D)

Very tube efficient on top of everything else they have going on ... What do you guys think?

Title: Re: Field Coils
Post by Kboe on 05/03/16 at 12:38:44

If only I had a big enough room! (OBs need big rooms right?)

Title: Re: Field Coils
Post by beowulf on 05/03/16 at 16:36:22

Yes, in general they need some room to breathe ... 4-5 feet off the back and side walls seems to be a good start ... I never heard the PAP stuff though.

Title: Re: Field Coils
Post by ProggRob on 05/04/16 at 04:37:15

I think I understand the merit of the field cool design, at least in theory. The magnetic field generated by the field coil isn't affected by the forces of the voice coil and so it exerts better control of the driver with less overshoot and therefore less distortion. The extra required power supply seems critical here, which could be $300 for an off the shelf unit or thousands for specialty designed tube-based units with very low ripple. Speakers like the Shindo Latour are of this design and have deity status in my mind (at least until I hear them) but perhaps I've exalted this technology unnecessarily. When I read comments like this it makes me wonder if the benefits of field coil are overblown?

"It's not practical. It can't be easily employed and is subject to more problems simply due to the increased parts count and design complexity. You are not going to find high frequency drivers that use an active magnetic structure short of electrostatic designs. There is some potential benefit in the additional power available though. Focal has decided to use the technology in the subwoofer of their Utopia EM systems. It allows more power to be delivered to the coil by any given amplifier than the ferro magnet. It is also adjustable, so that helps to tune the LF response to the room. And oh yeah, it's expensive. No reason in my pinion to go out of the way of 99% of the worlds best designs just to find a "full range" field coil speaker. It is an awkward answer searching for a niche problem to solve."

Title: Re: Field Coils
Post by ProggRob on 05/04/16 at 04:41:18

Beowulf, pricing was $8500 without the power supply. You could buy a recommended $350 off-the-shelf power supply or the WVL supply for $2600 additional.

Title: Re: Field Coils
Post by beowulf on 05/05/16 at 15:44:23

ProggRob wrote on 05/04/16 at 04:37:15:

Good post Rob! They seem very drool worthy, however I've never heard any field coils and wonder if I've overdrawn conclusions of them and placed them on a pedestal just due to their exoticness. I also wonder how much of a difference they would make over something like the Voxativ Treo15 model (though Voxativ does have field coils as well, but they are priced only for people who have their own private islands).

ProggRob wrote on 05/04/16 at 04:41:18:

Beowulf, pricing was $8500 without the power supply. You could buy a recommended $350 off-the-shelf power supply or the WVL supply for $2600 additional.

Although the PAP field coils do seem reasonably priced for what you get, that price alone puts them firmly out of my reach.

At any rate, I'm going to try and make it to T.H.E. Show in Newport this June ... hopefully the field coils will be demoing there and if so I'll report back (if I make it to the show that is).

Title: Re: Field Coils
Post by 4krow on 05/06/16 at 15:54:47

Awhile back, I had a conversation with Steve about some of the exotic speaker designs. He suggested an idea that he had heard of somewhere that used lasers intersecting at a 90 degree angle in airspace to produce a sonic response. I may have gotten this a bit wrong, but you get the idea. During this conversation, I realized that t wasn't just me who had a curiosity about imaginative speaker concepts. The field coil design went bankrupt in audio a very long time ago, most likely due to production costs. The electrostatic concept was another early design that was abandoned for decades until someone picked it back up. Turns out, the good old paper cone/magnet is relatively cheap to produce in comparison to the other concepts. In the end, I would be grateful to see more of these less popular designs come about just to hear the differences.