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.