JTR Noesis 212RT Measurements

[tuga]

 

[Xulonn]

Lovely sound of a french horn:

These speakers could be perfect for the Double Horn Double Bell. Perhaps you could even "tune" the speaker by sticking your hand in it - just as with a French Horn! (Just being humorous - I would be curious to see the results of Klippel measurement - which is not going to happen Wow- it might happen? - or double blind preference testing.)

 

[Xulonn]

Manufacturer has already contacted me.

Chicago is a long way from Seattle - will it be a loaner from a local PNW owner? Or is he going to actually ship ~140+ pounds back and forth just for testing?

 

[andreasmaaan]

You mean a Gueddes waveguide?
The manufacturer calls it a horn.

http://jtrspeakers.com/noesis-212rt.html

Geddes didn't invent the constant directivity waveguide, nor is his version the only possible one (valuable as his contribution was to the field of throat design for horns coupled to compression drivers).

The Geddes waveguide is in fact focused on minimising diffraction at the horn throat. It actually isn't the optimal design for directivity control, which is far more related to mouth geometry - an area Geddes did not give as much thought to (and indeed this shows in the measurements).

This JTR horn is in line with research on constant directivity horn design, albeit not the most cutting-edge research today. See for example Johansen (1994).

Having said that, my biggest concern about these beasts would be their vertical dispersion. Eyeballing these, I'd guess a C2C distance of around 35cm, which is large for a D'Appolito-style 2-way, even if crossed over as low as 500Hz.

I do wonder if the quasi-spinorama measurements shown in the review is based on both horizontal and vertical measurements, or whether it's based only on the horizontal measurements. If the vertical dispersion were also taken into account, I would have expected a bump in the DI / dip in the power response centred at 500Hz owing to the crossover.

 

[Jon AA]

Having said that, my biggest concern about these beasts would be their vertical dispersion. Eyeballing these, I'd guess a C2C distance of around 35cm, which is large for a D'Appolito-style 2-way, even if crossed over as low as 500Hz.

That's a good point. It may be the reason they are crossed as low as they are, even though as Matthew points out horizontal directivity could have possibly been made a bit more smooth in that region if crossed higher.

 

[Jon AA]

Chicago is a long way from Seattle - will it be a loaner from a local PNW owner? Or is he going to actually ship ~140+ pounds back and forth just for testing?

Could be worse, the 215RT's are 215 lbs.

 

[amirm]

Chicago is a long way from Seattle - will it be a loaner from a local PNW owner? Or is he going to actually ship ~140+ pounds back and forth just for testing?

I suspect they will ship one. Cost of doing business so not a big issue for a company.

 

[richard12511]

Could be worse, the 215RT's are 215 lbs.

I'd be curious to see how the Klippel would handle a speaker that big.

Doesn't Wilson make some that are like 1,000lbs?

 

[Thomas savage]

You need to learn to ignore clowns @Jon AA

This is not really helpful, we must avoid this kind of personal attack .

I know some characters can be frustrating but we don't want to be bringing ourselves down to this level.

 

[amirm]

I'd be curious to see how the Klippel would handle a speaker that big.

It might be tricky. I have the 2 meter extension for the Klippel but I don't know if I have enough ceiling height to go that high.

 

[Shazb0t]

It might be tricky. I have the 2 meter extension for the Klippel but I don't know if I have enough ceiling height to go that high.

Guess you have no choice but to start some work on the garage...

 

[Sal1950]

Good grief:

View attachment 59356

I may need to hire someone just to lift the darn thing onto measurement gear!

Get to the gym, or have Savage come by to help. LOL

Nobody is disputing there's probably some diffraction/reflections going on with the horn causing those ripples. Matthew even mentions that in the review. It's everything Tuga said about them that's wrong.

Jon, forgive my ignorance but what is the speaker in your avatar?

 

[MZKM]

Manufacturer has already contacted me.

I wonder how PowerSoundAudio’s speakers match up, as they have some similarities but are considerably cheaper (“only” uses 10” woofers).

 

[Haint]

What does the comparatively wide gap between the DI curves suggest?

 

[andreasmaaan]

What does the comparatively wide gap between the DI curves suggest?

The quite directional (60° x 60°) waveguide and the wide baffle mean that very little sound above about 400-ish Hz projects rearward.

The early reflections DI is contributed to by the front wall, back wall, side wall, and floor and ceiling reflections. The floor and ceiling bounce, as well as the back wall and lateral reflections, are all within +/-60°. It's only the front wall reflection that falls outside this angle. In other words, the early reflections DI is heavily skewed towards the +/-60° window.

Contrast that with the power response DI, which equally weights the speaker's output in all directions.

 

[TimVG]

Heard the monitor version of these which were placed on top of JTR's captivators at a friend's house in Holland - very nice stuff. I suspected they'd measure well and it looks to be the case. Would be interesting to see how they'd do on the NFS, but I'm not suspecting huge surprises. Jeff P. has never shied away from 3rd party measurements of his products which is something I appreciate.

 

[Jon AA]

Jon, forgive my ignorance but what is the speaker in your avatar?

It's a DIYSG HTM-8. SEOS 90 degree horn, which is excellent IMHO.

 

[tuga]

It's a DIYSG HTM-8. SEOS 90 degree horn, which is excellent IMHO.

Judging from these measurements the SEOS should be an immensely better performer than the pyramidal horn of the JRT.
Do you get this much treble roll-off?

 

[TimVG]

Judging from these measurements the SEOS should be an immensely better performer than the pyramidal horn of the JRT.
Do you get this much treble roll-off?

The treble roll-off is compensated for the in the crossover.

 

[pierre]

I compare it to the JBL M2. You need to complimentary subwoofer to match the M2 and graphs are not as smooth but directivity are very similar to me.