JTR Noesis 212RT Measurements

[LightninBoy]

I have my RTJ Audio system temporarily setup in my family room while my home theater is being finished.

I'm glad to read that its temporary. I love audio gear as much as anyone but even I recognize that blocking that view is sacrilege. Congrats on the new house and speakers!

 

[nerdoldnerdith]

I have my RTJ Audio system temporarily setup in my family room while my home theater is being finished. I've had these for several months now, but just moved them to this location this weekend. It is about 7' 8" to the top of the window and I think I have them about 11' apart. I've been to Rocky Mountain Audio Fest and AXPONA multiple years and to the LA Audio Show once. There is nothing I would choose above this system. I built my dream house and now I have my dream speaker system!

View attachment 147915

How loud have you played them?

 

[richard12511]

Is the horn shape slightly different around the edges? I can't imagine a home theater with these. Would be awesome.

 

[amirm]

Floyd Toole says the best performance can be expected when the subwoofers are "arranged to be 25% of the way from floor, ceiling and side walls, thereby attenuating the width and height modes, leaving only the length modes to be avoided."

These are theoretical ratios in perfectly dimensioned rooms. Real rooms are not always rectangular, nor are the walls perfect reflectors. Dr. Toole covers this in detail showing acoustic center of your rooms are different than computed ones based on dimensions. Regardless, even with the recommended positioning, you need to measure and apply EQ. As I noted, you can only fix some modes with subs on top of your mains assuming you pulled them out of the room that far.

As to concept of "plane wave" as you described, that just means that the subs are close enough to be treated as one. If they are, then they are not doing any mode cancellation.

 

[jeff permanian]

 

[danzilla31]

Jeff!!! Love the success your having all your hard work is paying off. That was a great article I really enjoyed it. Watching Matt obviously fall in love with those speakers and seeing them get the Don Dunn seal of approval totally made my day! I can't wait to see all the stuff you come up with next!

 

[Sal1950]

Jeff, having been a fan of horn/waveguide speakers for over 50 years I like to compliment you on the success of your design. Love to be able to hear them some day, maybe at some future post-covid audio show? I also am surprised at the very reasonable projected cost, you might just put the hurt on some of the big names. They will never be in this old mans budget or room size but at least I have something else to dream over.. LOL
Best of luck, Sal1950

 

[richard12511]

Have you ever considered an active speaker(I know you do it in your pro line)? I'd love to see what JTR/RTJ would be capable of with an active design. I might need to travel to hear these speakers. I'm in Texas, where is the nearest place I can hear this monster ?

 

[Chromatischism]

These are theoretical ratios in perfectly dimensioned rooms. Real rooms are not always rectangular, nor are the walls perfect reflectors. Dr. Toole covers this in detail showing acoustic center of your rooms are different than computed ones based on dimensions. Regardless, even with the recommended positioning, you need to measure and apply EQ. As I noted, you can only fix some modes with subs on top of your mains assuming you pulled them out of the room that far.

As to concept of "plane wave" as you described, that just means that the subs are close enough to be treated as one. If they are, then they are not doing any mode cancellation.

In my experience, they are if one sub is significantly delayed compared to the other. I had to do that with Dirac since it has no subwoofer integration. The best response came from delaying the rear sub by 16ms, and coincidentally the front sub was 16 feet away since the room is 17 feet long. Interestingly, I've only had good results with that when adjusting manually. When using Audyssey SubEQ, the optimal sub delays are not the same, and I'm not sure why. Using the -16/0 delays there gives bad results, so there is more going on.

 

[Chromatischism]

On the topic:

How much of a plane wave effect should we realistically expect with one sub at the front and one sub at the rear? In a small room I don't see why not. Maybe the effect reduces in a larger room and the sub count needs to then scale up.

 

[mjharden]

@amirm Did Jeff ever send you a speaker to measure? If so, do you have an ETA for the measurements? Skimmed through the thread, but didn't see anything. Thanks!

 

[mechtheist]

To understand what a waveguide is you need to first understand what a horn is. Wikipedia defines a horn as a musical instrument and this terminology came from the close appearance of the shape to horns found on wild animals.

This really exposes my serious affliction with 'SIWOTI', joining a forum to comment on this statement, in a 3 year old post no less, FFS what's wrong with me? But then, WTF, 'horn' as in the instrument got that name due to appearance? So the thousands of years where most horns were, well, horns had nothing to do with the name?

As an owner of this speaker, it was a little disappointing to find so few posts actually about it so far in this thread but maybe that will improve in the next 17 pages. I'm guessing the answe to the previous post is 'no', too bad.

 

[kma100]

AVS Forum has an active JTR thread.

 

[rcohen]

The transition doesn't look good and the off-axis FR doesn't look good either.

I just picked up a set of late 2022 212RTs.

The waveguide is hard to photograph because the speakers are so black. Using a flash helps.

It looks like the waveguides have evolved since the older photos. Although major official updates are rare, it's pretty common for JTR to quietly refine and improve their products over the years.

The throat of the waveguides has a very smooth transition. The visual boundary between the driver and the waveguide is misleading. It's seamless; you can't feel any edge. The transition between the throat and sides looks longer and smoother than before. There is a bit of an illusion in the photos that makes the transition look shorter than it actually is. The flare at the front of the waveguide is also seamless now. That's clearly different. A corner does remain on the baffle, as you can see in the photos.

 

[jlanzy]

Would the 212RT dispersion/directivity character be advantageous if speakers (movies only) were 13 ft apart and MLP at 12 ft. Speaker arrangement in well acoustically treated room 19x14x8, center, wide/side/back surrounds/ JTR 2400/JTR ULF4000/ ATI AT3005/Denon AVR85000. Trying to decide even if toed in towards MLP that the 'narrow' dispersion would be better than a wider dispersion speaker, was considering the JBL 4367 but the price difference is considerable. The new Arendal Tower 8 was also in consideration if they review well and are wide dispersion if wide would be a better listening experience for the mostly action/scifi/fantasy genre I watch at moderately high volume.

 

[chucky7]

Would the 212RT dispersion/directivity character be advantageous if speakers (movies only) were 13 ft apart and MLP at 12 ft. Speaker arrangement in well acoustically treated room 19x14x8, center, wide/side/back surrounds/ JTR 2400/JTR ULF4000/ ATI AT3005/Denon AVR85000. Trying to decide even if toed in towards MLP that the 'narrow' dispersion would be better than a wider dispersion speaker, was considering the JBL 4367 but the price difference is considerable. The new Arendal Tower 8 was also in consideration if they review well and are wide dispersion if wide would be a better listening experience for the mostly action/scifi/fantasy genre I watch at moderately high volume.

I point my 212RTs at my left and right ear when seated at MLP (at left of the center line of room). My untreated HT is 14.5' wide and MLP is at ~12ft. The imaging is very solid and it sounds like a wall of sound. I can't ask for more.

The following video doesn't do it justice, but should give you a pretty good idea of how they sound.

 

[jlanzy]

Chucky7 your front stage is awesome, thanks for the photos. Your room is very close to my room size and seeing how content you are I no longer have concerns that these would sound disjointed in my theater room especially for the movie genres I watch and at moderately loud volume. I love JTR's subs and I suspect I would love the Noesis 212RT as well.
Happy listening.

 

[AdamG]

View attachment 403807

I point my 212RTs at my left and right ear when seated at MLP (at left of the center line of room). My untreated HT is 14.5' wide and MLP is at ~12ft. The imaging is very solid and it sounds like a wall of sound. I can't ask for more.

The following video doesn't do it justice, but should give you a pretty good idea of how they sound.

Hi Chucky7,

Admittedly I have not kept up with your upgrade path recently. But it looks like you have added another earth crushing Sub. I know that is a Captivator 4000ULF on the right. Is that new addition Sub on the left a Captivator 4000ULF-TL ? So you upgraded to dual 4000ULF’s? Holy hell dude that’s insane. What SPL are you capable of now? Got any recent in room measurements you wish to share?

I can only imagine what that pure JTR wall of sound must measure like. Must be audio bliss and house shaking power down below single digits. Congratulations old friend as that is one hell of a system. Love it!

 

[amirm]

@amirm Did Jeff ever send you a speaker to measure? If so, do you have an ETA for the measurements? Skimmed through the thread, but didn't see anything. Thanks!

Nothing like answering a two year old question.

Jeff did send me a prototype speaker. I don't know if he ever decided to finish it so I did not publish the results. It was a single, coaxial driver. Here is its response:

 

[chucky7]

Hi Chucky7,

Admittedly I have not kept up with your upgrade path recently. But it looks like you have added another earth crushing Sub. I know that is a Captivator 4000ULF on the right. Is that new addition Sub on the left a Captivator 4000ULF-TL ? So you upgraded to dual 4000ULF’s? Holy hell dude that’s insane. What SPL are you capable of now? Got any recent in room measurements you wish to share?

I can only imagine what that pure JTR wall of sound must measure like. Must be audio bliss and house shaking power down below single digits. Congratulations old friend as that is one hell of a system. Love it!

Hi Adam,

Thank you!

Yeah, that is a Captivator 4000ULF-TL on the left. Originally I wanted to put a Cap 4000ULF in the rear of the room so the TL form factor with the smallest footprint allows the most placement options. I ended up putting it at the front for shock and awe and the port wind. Surprisingly, the FR turned out fine. I also scored a PSA S42 Ipal (dual 21", 4000W) that I want to put VNF just behind my MLP. I should be reference capable at <5% THD. I have not done any compression sweeps for a while but I did find that using miniDSP 2x4HD to achieve a flatter response will hinder the headroom if there is too much lifting applied...

As for room measurements, the most recent compression sweeps were done in 2022 so I am sure you have seen them on AVS forum.

Now my bed layer spakers are all JTR: Noesis 212RTs mains and side surrounds, 212HTR center, and 228HT rear surrounds. I am renovating my HT now so when I am done, I will have a 7.1.4 (3 subs) with JTR bedlayer speakers and 4 JBL AWC82 Atmos.