Klipsch RP-150m 45 degrees off axis measurement.

[yepimonfire]

Measured in the farfield @ 4', 66dB, 1/24th/octave smoothing ,windowed response of 3.8ms in the right window (below about 500hz is cut off by the window).

-6dB from 7khz-14khz (+3dB,-2dB response in the pass band) with a 12dB/octave decline above 14khz, indicating the horn fails to maintain control of frequencies greater than 14khz.

 

[shadyJ]

The dynamic range of that window is a bit wide. I would squeeze it down to 50 dB to 100 dB for a clearer look. Also, set the bandwidth to 200 Hz to 20 kHz. You aren't getting anything usable below 500 Hz if this testing was conducted indoors, so there is no need to include the bass region at all.

You might also want to overlay this against a on-axis measurement, a 15 degree, and a 30 degree response, that will help us understand its behavior better.

 

[Swerd]

I agree with shady, adjust the SPL (vertical) axis so that the space between horizontal lines is wider, and the markers are at every 10 dB, better yet every 5 dB.

The loss above roughly 14 kHz may be your microphone or the tweeter itself.

However the big question is why is there such a deep and wide dip, roughly 10 dB deep, between 300 and 400 Hz? I also see the SPL below ~250 Hz (below the dip), is roughly 5-10 dB lower than above ~500 Hz (above the dip). That was with the microphone is 45° off-axis. What happens at 0°, 15°, or 30°?

What's going on at this frequency? Is there a crossover at this frequency?

 

[shadyJ]

I agree with shady, adjust the SPL (vertical) axis so that the space between horizontal lines is wider, and the markers are at every 10 dB, better yet every 5 dB.

The loss above roughly 14 kHz may be your microphone or the tweeter itself.

However the big question is why is there such a deep and wide dip, roughly 10 dB deep, between 300 and 400 Hz? I also see the SPL below ~250 Hz (below the dip), is roughly 5-10 dB lower than above ~500 Hz (above the dip). That was with the microphone is 45° off-axis. What happens at 0°, 15°, or 30°?

What's going on at this frequency? Is there a crossover at this frequency?

The stuff below 500 Hz is going to be affected by the room. I would not attribute it to the speaker.

 

[Swerd]

The crossover freq of the RP-150m is 1500 Hz. I didn't really think there was a crossover at 300-400 Hz, but I looked it up to be sure http://assets.klipsch.com/product-specsheets/RP-150M-Spec-Sheet.pdf.

In my limited experience, I usually see room effects below ~250 Hz, not in the 300-400 Hz range. A frequency of ~330 Hz would have a wavelength of ~3.4 ft. I couldn't make a guess about it unless I know the room dimensions.

If it is a room effect, especially floor bounce, it would change as the microphone distance changes. The original measurement was taken at 4 feet. What happens to that dip at other distances and other angles?

 

[KEW]

Also, set the bandwidth to 200 Hz to 20 kHz. You aren't getting anything usable below 500 Hz if this testing was conducted indoors, so there is no need to include the bass region at all.

Maybe you know something I don't, but I do want to know my in-room FR for the full range.
I agree that the bass measurements are unique to his room/layout, but they are arguably the most important measurement he can make of his system/setup!

 

[shadyJ]

I agree that the bass measurements are unique to his room/layout, but they are arguably the most important measurement he can make of his system/setup!

He is trying to show the response of the speakers themselves, not the room.

 

[yepimonfire]

The stuff below 500 Hz is going to be affected by the room. I would not attribute it to the speaker.

The IR window messed it up. It was reasonably flat from 47hz on up with a peak at 50hz due to room interaction at the mic position.

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[yepimonfire]

I agree with shady, adjust the SPL (vertical) axis so that the space between horizontal lines is wider, and the markers are at every 10 dB, better yet every 5 dB.

The loss above roughly 14 kHz may be your microphone or the tweeter itself.

However the big question is why is there such a deep and wide dip, roughly 10 dB deep, between 300 and 400 Hz? I also see the SPL below ~250 Hz (below the dip), is roughly 5-10 dB lower than above ~500 Hz (above the dip). That was with the microphone is 45° off-axis. What happens at 0°, 15°, or 30°?

What's going on at this frequency? Is there a crossover at this frequency?

The loss above 14khz is off-axis roll off. It's flat out to 24khz with 1m on axis measurements. The whole point of this was to demonstrate the constant directivity design of the redesigned modified horn. The crossover frequency is actually 1800hz. Everything above 500hz in the graph, as I mentioned in my OP, has been altered by the IR window. There is no point I'm taking an off axis measurement in the farfield without a window, the room is too much of a factor at that point.

Anything past 15° off axis shows similar behavior, with frequencies >14khz rolling off at an increasing slope the further off axis you get.

I did have a 5° space originally, I guess when I hit the image capture button in rew it shrunk it and I didn't realize it until you brought it up. I will add more measurements at 15° and 30° and a graph with wider range later this morning after work.

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[yepimonfire]

Maybe you know something I don't, but I do want to know my in-room FR for the full range.
I agree that the bass measurements are unique to his room/layout, but they are arguably the most important measurement he can make of his system/setup!

I already have one, the point of this measurement was the off axis response, at the main listening position on axis, the response is 47hz-24khz +-5dB. With the sub engaged it's 25hz-24khz +-5dB with 25hz being -3dB. The off axis measurement is 3' from the side wall which is why I windowed the response. I suppose it'd be better to include all measurements for a better picture.

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[everettT]

I agree with all of the above. Taking measurements for understanding a speaker or room is beneficial, not using the proper procedures and methodology will be less than beneficial. Hopefully someone will donate a set of these series for review , as there has been a lot of talk as to a new sound signed.

 

[TheWarrior]

Hopefully someone will donate a set of these series for review , as there has been a lot of talk as to a new sound signed.

Or put the speaker through CEA 2034 so the OP can understand what a Directivity Index is

 

[shadyJ]

The IR window messed it up. It was reasonably flat from 47hz on up with a peak at 50hz due to room interaction at the mic position.

What distance did you measure at? Remember that distances from the microphone where the wavelength of the frequency is longer than the shortest path from speaker to nearest surface to microphone are going to be ruined by those reflections, which is why it is necessary to window that stuff out. You do not have a reliable way to measure bass frequencies where the distance exceeds wavelengths larger than acoustic reflections off of nearest surface. You will have to use close mic techniques for that or outdoor groundplane techniques. If you want to get technical, here is a paper by Don Keele where he invents a technique for gathering frequency response of bass by near-field measurements.

 

[ATLAudio]

I wish I understood the OP's point here.

Brent Butterworth measured the RP-280FA, and I believe that you'll see nearly identical off axis performance through out Reference Premier line.

 

[ATLAudio]

@yepimonfire

What measuring equipment are you using?

 

[yepimonfire]

I wish I understood the OP's point here.

Brent Butterworth measured the RP-280FA, and I believe that you'll see nearly identical off axis performance through out Reference Premier line.

"In the first chart, you can see that the RP-280FA delivers an impressively flat response on- and off-axis, but it has a slightly rising treble response, with about +1 to +2 dB of added output from 5 to 10 kHz. As a result, the off-axis averaged response is almost perfectly flat. "

That was the point I was making, that the response off axis is excellent when compared to older reference II speakers.

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[ATLAudio]

@yepimonfire

You’re clearly begging the question that the Reference II series doesn’t share a similar behavior. In fact it does; rising slightly on axis while being flat off axis down about 15 degrees. I assume you've abandoned your 90 degrees off axis claims?

Moreover, the important thing to observe is that the difference is 1-2 dB from 5-10 khz, which is a proper observation of off axis performance; ie none of this evaluating full range BS. That said, I have no doubt that the RP has improved off axis compared to Reference II, but it’s subtle, and difficult to compare properly with even experienced technique, and proper equipment.

In conclusion,

1. Learn to use proper technique before making definitive measurement claims.

2. Purchase quality equipment to make said definitive claims. Spoiler: it’s expensive.

 

[Pogre]

@yepimonfireIn conclusion,

1. Learn to use proper technique before making definitive measurement claims.

2. Purchase quality equipment to make said definitive claims. Spoiler: it’s expensive.

This.

@yepimonfire, I've read quite a few of your posts and from that I've drawn the conclusion that you're very passionate about audio and are willing to educate yourself and put some work into it.

Sometimes you state your findings as fact though, when the process is flawed or maybe you just don't have a correct understanding yet. IMO, a lot of those statements should be more in question form. You never know who might read one of those replies and take it as fact.