RBR-KIT mod with neoCD3.0 ribbons?

[Coconutout]

Jed i hope you aren't offended by what i'm about to ask here and apologize deeply if you are... i respect your work and am appreciating every moment of it. right now my RBRs are playing me the smoothest music with the softest mid/bass that i've ever heard with the paper cones which were the deciding factor when i was choosing rbrs over all the other options. i don't regret the choice- i think SS revelators are insane performers that can do some unreal things; and once again, i have a thing for soft textured bass that only paper cones can provide
but having owned the statements as my last pair, i realize some trade-offs have been made. mainly in the area of imaging and detail with the ribbon tweeters... of which i still own a pair of! so my only regret is that i have a pair of NeoCD3.0 that are just sitting around gathering dust. i'd like to use them to bring the RBRs to a new level of sweetness never existed before. this inspiration comes to me along with the need to rebuild the cabinets to go with my next subwoofer project. Please Jed, i'd like to know what kinds of crossover mod is needed to team up these two over-achievers together.

[Hdale85]

I'd imagine a nearly full redesign...

[JonMarsh]

Well, I'm not the one to put words in Jed's mouth, but my first impression is that it's arguable that a ribbon like smaller NeoD 3.0 is not going to be happy with a 2nd order LR HP only 10 dB down at 2 kHz. But I could have that all wrong. IMO, the Neo's work better in three ways with a higher crossover point. Think Statements. Think 3.5-4 kHz crossover. Might work if you don't plan on too much SPL.

This is where the "Y" in DIY comes in.

[Jed]

The RBR uses an asymmetric slope crossover approximating LR4 phase characteristics. In other words the woofer is more like a flat delay 3rd order and the tweeter LR4. This is needed to align the phase do to the drivers' acoustic center not being aligned on a flat baffle. Jon is right that most ribbons aren't comfortable with a crossover point around 2.5k. The Fountek is better around 3.5k LR4, which is doable but then the tradeoff would be a beaming midrange/bass driver because the 5.5" driver is better used below 2.5k or so. Not saying it can't done but expect a full crossover revision.

The SB tweeter is very clean, but a ring dome will never have the top end "sparkle" the ribbon is known for. Tradeoffs.

I'm doing a version with the Scan Speak HDS tweeter to help bridge that gap. Some say the HDS has a really airy top end. We'll see.

[Jed]

By the way, do you have any pics of your finished speakers?

[rhubarb9999]

I will take those NeoCD 3.0s off your hands if you decide you don't want them. PM me

[Coconutout]

ah, thank you, gentlemen. i forgot to mention that i know nothing about speaker design but you guys are helping me slowly change that. yes, the discovery might be the answer i'm looking for, Jed. I'll be the 1st one to jump in on it. a trivial issue i'm wondering about is would i be able to take the crossover out through the brace and the mounting hole of the enclosure if i need to modify it? yes i can take pics of my pair but i have to warn, it is in no shape to be bragged about... the woodshop that built it for me did a total botch up job where they cut an oval shaped mount for a 2port flange and the side panel doesn't even fit evenly. adding to the blow was the quality of birch ply they used which reeked of formaldehyde glue... typical chinese workmanship. at least they save the best for exports. so to combat the smell i had to drench the boxes with anti-formaldehyde paint thats more of a clay emulsion than a smooth applying liquid. surface ended up having the texture of a rough clay sculpture- very unphotogenic... like they say, if you want it....... you gotta do it yourself. which's why i'm remaking the enclosure with hardwood. i'll still be taking the pic of this build before i smash it to get the crossovers out.

I will take those NeoCD 3.0s off your hands if you decide you don't want them. PM me

hehe. thanks for your concern but i'm gonna save them for a future ambitious what-if.

[Rick Craig]

Jed i hope you aren't offended by what i'm about to ask here and apologize deeply if you are... i respect your work and am appreciating every moment of it. right now my RBRs are playing me the smoothest music with the softest mid/bass that i've ever heard with the paper cones which were the deciding factor when i was choosing rbrs over all the other options. i don't regret the choice- i think SS revelators are insane performers that can do some unreal things; and once again, i have a thing for soft textured bass that only paper cones can provide
but having owned the statements as my last pair, i realize some trade-offs have been made. mainly in the area of imaging and detail with the ribbon tweeters... of which i still own a pair of! so my only regret is that i have a pair of NeoCD3.0 that are just sitting around gathering dust. i'd like to use them to bring the RBRs to a new level of sweetness never existed before. this inspiration comes to me along with the need to rebuild the cabinets to go with my next subwoofer project. Please Jed, i'd like to know what kinds of crossover mod is needed to team up these two over-achievers together.

It can easily be done with a crossover change. I've used the CD3.0 in several designs and as long as the woofer can support a 2.7K or higher crossover point it sounds great.

[---k---]

Sounds like he should contact you or Jed for a quote to develop a custom speaker design.

[Jed]

If he can send me a speaker cabinet with the drivers loaded I'll do it free for the board. Measure, develop the crossover, post schematic, etc. That is if there are other RBR owners that want to try a ribbon.

[Jed]

The crossovers are small enough to go through the holes. I don't see why you have to smash your cabinet to get them out. Unless you used some heavy duty glue of course.

[ThomasW]

If he can send me a speaker cabinet with the drivers loaded I'll do it free for the board.

He's in China

[Coconutout]

yes i did use some heavy duty glues... half a bottle of aquarium silicone to be exact- dabbed the whole backwall to dampen it before i dropped the crossover in there. i'd have to pry open the side panel and cut it out with a knife. and sorry, i'm in china...

[Coconutout]

is there any hope of seeing this mod to fruition, Jed? i'm really eager to take the RB part out of the title and replace it with Ultimate

[Jed]

is there any hope of seeing this mod to fruition, Jed? i'm really eager to take the RB part out of the title and replace it with Ultimate

I'd need a test cabinet with the drivers loaded to run a new set of measurements. Otherwise I'd just be guessing with simulations and not really know what the phase is doing in reality. When I take measurements, I do it as a system to determine the driver locations, z offset, relative sensitivities etc. If I took a measurement from another batch, say from my Lineup R4. and normalized everything, it would only be a good guess because the measurements came from very different conditions and mic locations etc.

[Coconutout]

thank you Jed, I appreciate the offer but i think the cost of shipping a speaker from china to NY would be too extreme for my budget and add the possibility of a month long wait or longer (rbr kits from madisound took 3 weeks...) what i wouldn't mind doing is, if you think it's feasible, try out various crossover schemes that you could theorize for me and settle for the one that sounds best to my ears... for now. i'd be able to send you a cabinet without frowning at the cost once i move back to the states after new years but would love to hear how a rough integration of the two fabulous drivers sound like before that.

[Hdale85]

The new year isn't to far away.