Building field coil speakers Rullit Aero

[jlsemrad]

I've heard Rullit several times, but I liked them best on the horn.
At ebay you find such tractrix horns for 8"and 10" fieldcoils
View attachment 151532

Those don't look very much like tractrix horns. This is a tractrix:

 

[LanschePlasmaGuy]

Those don't look very much like tractrix horns. This is a tractrix:

I love the look of the Semrad horns (and the choice of gear and music in the Youtube clips i've seen). I've got quite a few of the French SAM records Jazz vinyl's and love them.

Did you try any other front horn profiles for the Rullit Super Aero's you are using and what was the benefit in sound of the tractrix profile you used?

How did the rollover you're using effect the sound (it must have been significant or you wouldn't have used it because the horn could be much smaller in dimensions with the rollover or you could have made the tractrix profile extend to the current dimensions, extending the low end allowing the helper woofer to crossover lower).

Did you have a preference for the Rullit Super Aero 8, 9 or 10 inch in your front loaded horn experiments? (In an open baffle hearing them at a range of different places and systems my strong preference is for the Super Aero 9).

I would love to hear your speakers in Australia!! Do you have a distributor here?

LPG

 

[jlsemrad]

I love the look of the Semrad horns (and the choice of gear and music in the Youtube clips i've seen). I've got quite a few of the French SAM records Jazz vinyl's and love them.

Did you try any other front horn profiles for the Rullit Super Aero's you are using and what was the benefit in sound of the tractrix profile you used?

How did the rollover you're using effect the sound (it must have been significant or you wouldn't have used it because the horn could be much smaller in dimensions with the rollover or you could have made the tractrix profile extend to the current dimensions, extending the low end allowing the helper woofer to crossover lower).

Did you have a preference for the Rullit Super Aero 8, 9 or 10 inch in your front loaded horn experiments? (In an open baffle hearing them at a range of different places and systems my strong preference is for the Super Aero 9).

I would love to hear your speakers in Australia!! Do you have a distributor here?

LPG

The picture that I attached was a horn that I built about fifteen years ago for a prototype 12" Rullit driver that belonged to a good friend of mine. I believe that it was the first Rullit driver to make it stateside. It has a tractrix (or possibly a kugelwellen, knowing Oleg) profile, drawings of which were provided by Rullit.

The horns that I currently build for the audiophile market have a Le Cléac'h flare which allows for full horn loading with a slightly shorter depth. I prefer the Super Aero 9 to all other Rullit drivers that I have listened to, and we use them exclusively for our horns. Although it is nominally a 9" driver, the horn throat is only 6" in diameter to get the optimum impedance for best efficiency. The crossover frequency is just slightly higher than the horn cut-off. We finally settled on a Linkwitz-Riley second order crossover.

You are correct in stating that the Rullits are finicky until they have a goodly number of hours on them. I've had a couple of embarrassing moments at shows when they decided that they needed to do something differently after we thought the room was well set up.

John

 

[Lautreamont]

The picture that I attached was a horn that I built about fifteen years ago for a prototype 12" Rullit driver that belonged to a good friend of mine. I believe that it was the first Rullit driver to make it stateside. It has a tractrix (or possibly a kugelwellen, knowing Oleg) profile, drawings of which were provided by Rullit.

The horns that I currently build for the commercial market have a Le Cléac'h flare which allows for full horn loading with a slightly shorter depth. I prefer the Super Aero 9 to all other Rullit drivers that I have listened to, and we use them exclusively for our horns. Although it is nominally a 9" driver, the horn throat is only 6" in diameter to get the optimum impedance for best efficiency. The crossover frequency is just slightly higher than the horn cut-off. We finally settled on a Linkwitz-Riley second order crossover.

You are correct in stating that the Rullits are finicky until they have a goodly number of hours on them. I've had a couple of embarrassing moments at shows when they decided that they needed to do something differently after we thought the room was well set up.

John

Thank you very much for the great insights.

Are there any plans on front loaded horn designs anywhere and what type of wood does people recommend?

I have heard a lot of people recommending the 9 inch driver from the 8 and 10 inch so I want to proceed with the 9 inch since it seems that it accommodate my musical preference as well. Is there some things that are “good to know” when dealing with 9 inch drivers?

I have heard a great deal about resonance cabinets or cabinets with an empty back (like open baffle but still closed designs) perhaps they could promote the best qualities of the driver whilst still not requiring so much space.

 

[Lautreamont]

Atelier Rullit Hornlautsprecher

www.cjm-audio.de

Perhaps one can guide me to a place where I can find DIY plans similar to the latter model?

 

[Lautreamont]

Hello again everyone.

I have made a few minor corrections to my listening room and I think I can (will) proceed with an open baffle design.

Does anyone have cabinet plans or help to how I get measurements, dimensions right?

 

[dcathro]

Hello again everyone.

I have made a few minor corrections to my listening room and I think I can (will) proceed with an open baffle design.

Does anyone have cabinet plans or help to how I get measurements, dimensions right?

If you download Tolvan Edge, you can simulate baffle size and driver position.

 

[Lautreamont]

"

If you download Tolvan Edge, you can simulate baffle size and driver position."

Thanks! I do not have the technical data of the Rullit though. They are a kept secret for the manufactor and I will respect Mr. Oleg disposition in this matter.

 

[dcathro]

"

If you download Tolvan Edge, you can simulate baffle size and driver position."

Thanks! I do not have the technical data of the Rullit though. They are a kept secret for the manufactor and I will respect Mr. Oleg disposition in this matter.

You don't need any data, the software assumes a perfect driver. You model the effect of baffle size, shape and position of the driver.

 

[Lautreamont]

Hello everyone.

Just a minor upgrade on the project.

I have contemplated for some time and corresponded with people who own (or have owned) Rullit drivers and experimented with cabinets. After all of this I'm left with an unresolved, ambivalent mind.

On one hand the mysterious magic of the handmade drivers are luring and on the other hand, this project is perhaps too risky for me at this moment. I'm not saying it's not a great driver, but perhaps I have been a bit spellbound with the idea. The field coil drivers are not cheap (7.000€ for the nine inch and that's without a dedicated power supply) and therefore it can be too risky to invest in such a project not knowing beforehand, that I will get great results. I like the concept of a full range system because it can promote realistic sound, however the compromise can be significant. It would be a shame to install the system and be left with "I lack bass" or "I'm not satisfied with the higher frequencies".

I will do some more investigation whilst still thinking about other options. I have another thread where I ask for speaker recommendations and I'm happy for all of your suggestions. Right now I'm thinking about the Tonapparate Model 55 (field coil) whilst also considering the recommendations you've given in this thread (Treehaus, Songer - I appreciate your dedication and thank you very much for reaching out to me personally in this thread).

 

[LanschePlasmaGuy]

Hello everyone.

Just a minor upgrade on the project.

I have contemplated for some time and corresponded with people who own (or have owned) Rullit drivers and experimented with cabinets. After all of this I'm left with an unresolved, ambivalent mind.

On one hand the mysterious magic of the handmade drivers are luring and on the other hand, this project is perhaps too risky for me at this moment. I'm not saying it's not a great driver, but perhaps I have been a bit spellbound with the idea. The field coil drivers are not cheap (7.000€ for the nine inch and that's without a dedicated power supply) and therefore it can be too risky to invest in such a project not knowing beforehand, that I will get great results. I like the concept of a full range system because it can promote realistic sound, however the compromise can be significant. It would be a shame to install the system and be left with "I lack bass" or "I'm not satisfied with the higher frequencies".

I will do some more investigation whilst still thinking about other options. I have another thread where I ask for speaker recommendations and I'm happy for all of your suggestions. Right now I'm thinking about the Tonapparate Model 55 (field coil) whilst also considering the recommendations you've given in this thread (Treehaus, Songer - I appreciate your dedication and thank you very much for reaching out to me personally in this thread).

Hi Lautreamont.

We have all been responding to your many questions. Good luck with your quest.

If you bought a Treehaus Audiolab speaker, Songer or Semrad you would have I think a game over, slam dunk, top of the mountain, everest quality speaker system. If you pay the money you will get the results.

If you feel you don't have the skills to build your own it sounds like its best to look at other options and ask other peoples opinions.

It's a pity you couldn't work this one out. You could have ended up with an amazing speaker music making system.

LPG

 

[Lautreamont]

Hi Lautreamont.

We have all been responding to your many questions. Good luck with your quest.

If you bought a Treehaus Audiolab speaker, Songer or Semrad you would have I think a game over, slam dunk, top of the mountain, everest quality speaker system. If you pay the money you will get the results.

If you feel you don't have the skills to build your own it sounds like its best to look at other options and ask other peoples opinions.

It's a pity you couldn't work this one out. You could have ended up with an amazing speaker music making system.

LPG

I have tried to show my gratitude in a lot of my posts and I'm still sorry that I didn't know that the "like" button meant so much to people.

Treehaus, Songer and Semrad is definitely on my list as well.

I have heard a lot about people being dissatisfied with the compromise of the full range system and it means I'm a bit nervous about proceeding. I don't find it obvious that I will get the results by paying the money rather it seems that DIY projects appear to take lots of time and effort - which makes sense - before getting the right sound.

If I had a complete plan then I could think about it.

 

[DaveC]

I have tried to show my gratitude in a lot of my posts and I'm still sorry that I didn't know that the "like" button meant so much to people.

Treehaus, Songer and Semrad is definitely on my list as well.

I have heard a lot about people being dissatisfied with the compromise of the full range system and it means I'm a bit nervous about proceeding. I don't find it obvious that I will get the results by paying the money rather it seems that DIY projects appear to take lots of time and effort - which makes sense - before getting the right sound.

If I had a complete plan then I could think about it.

It depends on what you want. Single driver can be as good as it gets for some music, but if you want to play symphonic music at realistic SPLs, you'll certainly be disappointed.

I'd consider looking around for a used or reasonably priced SD speaker to try out. You'd have to check out what's available locally. If you were in the USA I'd suggest just buying an Omega single driver speaker, and still would depending on shipping costs. You're buying direct without the high-end luxury markups.

Omega Speaker Systems

Omega Speaker Systems

omegaloudspeakers.com

If you do decide to DIY, I'd recommend NOT using OB, I've tried it and I dislike it. It's easier than any other design to implement, but that's its only pro and there's lots of cons.