Atelier Rullit field coil driver

Field coil driver’s are 1920’s technology! The World has moved on! Why don’t you choose a proven classic design like the Quad 57’s? I have two pairs. For sub-90 db listening they are unequaled!

If you must have a moving coil speaker get a Lowther driver in a folded horn cabinet along with a single end 300B amp.

Hello Jason

It is not a moving coil speaker but a field coil. And yes, the technology is quite old but that doesn’t mean anything. In fact I think that field coil based speakers are superior to most systems that are built today. I’d rather have a efficient and a somewhat “full range” system instead of speakers with complex technology and complicated crossovers. 
 

Field coils can be some of the best drivers out there, look as Voxativ's top models all field coils. but in my experience, they require lots of money to get right. one of the biggest issues we have had is getting the field coil power supply noiseless. especially hi sensitivity speakers like horns. I have too close friends who run field coils, and they are both now moving away from them due to power supply issues.

 If you have the money to do it right and get the power supply that is very good, then go for it some of the best sound I’ve heard. If you’re on a budget, I would not recommend it. Just a quality power supply for a field coil is going to cost what a top-notch amp will, and you need two.

Both my friends did the field coils in open baffles by the way, they both moved away from cabinets due to the cabinet sound. Once you go OB its hard to go back to a cabinet, i.e. once you hear a cabinet you can’t unhear it.  Granted you have the room for them and I think you do.

The field coil driver I'm considering is among the best drivers to have ever existed. I will keep in mind investing in a proper, valve-based power supply. 

I believe that OB need a lot of space around them. I would love to have the Telefunken design but my interior doesn't allow for their placing. 

I have heard the Atelier Rullit field coil driver in Trehause open baffle speakers.  I cannot attribute specific qualities to that driver, but, I can say that these were not among my favorite open baffle speakers; the sound was a little thin and rough.  Not a bad speaker, but, not the best in my opinion.  Among the better field coil wide range driver systems I've heard is the Songer Audio model; the sound was rich and free of the kind of harshness or peakyness that I hear with some full-range driver systems yet it retained the dynamic qualities of such drivers.  The Audio Note two-way AN-E speakers with field coil drivers sounds good too, and it is not a fiddly thing (one does not have to adjust voltage) and it appears to overcome a common problem with field coil speakers in an enclosed box, which is overheating.

I've heard many custom-made systems employing field coil full range drivers and field coil midrange compression drivers for horn-based systems.  As mentioned above, overheating is an issue with enclosed cabinet systems, and for some systems, the ideal sound requires a bit of adjusting of the voltage as the system warms up.  With the compression drivers, I heard a pretty substantial difference in sound based on the power supply feeding the drivers.  I was shocked to find that the power supply made such a big difference; the tube-based supply sounded better than a solid state supply.

I'm not interested in field coil drivers, but for my vintage 8 inch drivers (and a small room like yours) I would consider Oris 250 horns mated with the little Gallo 3 subs  (no lower cutoff on the horns and the tight sounding subs extend to 200Hz+).

The horns/subs would come in at under $2.5K (new) and you would just have to DIY stands for the horns.

You could experiment with various drivers using this setup.

DeKay

Dekay

Thanks you for your post. If I went for an independent bass solution I would need two amplifiers, right? That makes it a bit complicated I would say and too complicated for my taste.

Larryi

Thanks you for your post. I have already learned that investing in a proper, high quality power supply is an absolute must.

I already own a pair of entry level Audio Note speakers (D/J) and I would love to have their field coil models, however they start at 65.000$ which is too much for my budget. The field coil driver I'm looking at is around 5000€ and a cabinet can probably made for less. 

It's funny with Treehaus. It seems they are doing everything right: the driver, the cables, the setup. Even their amplifiers run with the outstanding Finemet output transformers and I have a feeling there is mixed feelings about it. I have thought about buying a pair though even though I would prefer a cabinet that doesn't require 1m+ from the wall.

I thought on a closed cabinet but with empty back like resonant cabinets. 

The compact Gallo TR3 subs are "self powered" and would just need to be adjusted (on the back) to the horns.

They are a typical powered sub with an onboard crossover network.

Two would be required as bass becomes noticeably directional above 60 Hz, or so (one sub per channel located close to or below the horn).

Figured it’s a realistic approach considering the room size/budget.

I’ve tried the TR1 and TR2 subs with some of my single drivers and they mated/blended quite well crossed over @ 100Hz.

Plus the 250 horns are not that large/deep.

PS: You need to use the low level inputs on the subs for the crossover frequency adjustment to be active.

https://galloacoustics.com/product/tr-3d/

DeKay

You might consider the PureAudioProject open baffle speakers.  Their Quintet models feature four 15" woofers, with various modules for midrange/tweeter that fits in the middle.  These modules include a horn option, a coaxial driver option and a couple full range driver options, including a Voxativ field coil option.  They have a smaller speaker called the Trio, which features twin 15" woofers and the same array of midrange/tweeter modules.  Another great sounding open baffle system is made by Cinnamon Audio--it uses an AMT tweeter and active, DSP-controlled woofers. To me, these are very good sounding systems. 

Songer Audio makes a single driver field coil system that is also very good sounding.  Another speaker I really like is the Companion model from Charney Audio.  This is a single driver, backloaded horn system that is impressively full range for a single driver system.  The offer a variety of choices for that single driver, including models from AER and Voxativ. 

My favorite speakers are not regular commercial products; they are custom made horn-based systems from Deja Vu Audio (Vienna Virginia) that utilize some very old midrange compression drivers and horns as well as modern custom made woofers and tweeters.  They make speakers from about $10k on up to who-knows-where.  The better models use drivers from the 1930's-1960's, and horns from the same era.  At their shop, they even have a massive Western Electric 16A horn with vintage drivers and modern woofers and tweeters (the horn is three years shy of being 100 years old).  Fun stuff.  If you can make it to the Washington DC area, this is the place to visit for out of the ordinary gear (they also make their own tube amps, linestages, phono stages and DACs).

Thank you for all the kind recommendations, although I might accentuate that I'm looking for a suitable cabinet idea for the Rullit field coil driver.

The appropriate cabinet will depend on the specific design of the driver.  The manufacturer can tell you if it is designed for open baffle, sealed cabinet or bass reflex and the appropriate cabinet volume.  Drivers don't behave ideally in different types of systems, although manufacturers may make different models for different uses.  I heard that driver in two different systems, both were open baffle.  

Also, a local speaker builder who uses field coils in some of his builds has encountered problems with overheating when field coil drivers were used in closed cabinets.  That is probably another thing to ask the manufacturer about.  Audio Note makes a seal cabinet speaker (AN-E) with both the woofer and tweeter being field coil drivers, but, they claimed that keeping heat down to acceptable levels was a major engineering challenge.

@apollinaire head over to WBF and you'll see a great thread about Rullits. A friend of mine has the 9 inch Super Aero, and i've heard them in an open baffle and they were superb. He's now working on horn loading them.