# Klipsch RF-82 measurements



## vann_d

Hi All,

So the wife and kid are out for the weekend and I finally get to dork out with my system 

I'm in the process of really trying to calibrate my system and by that I mean matching levels and equalizing the sub. Plus I'll be doing some video calibration.

Along the way, I thought I'd do some of those nifty progressive SPL plots to locate compression in the system (i.e. measure maximum clean SPL output). I've only seen these measurements done for subwoofers on the regular forums. I thought it would be nice to do the same on a full range loudspeaker measurement. I have a rudimentary understanding of how to do these measurements but if I'm messing something up please tell me so I can learn.

My system consists of Klipsch RF-82 LR mains, RC-52 center, and RB-15 surrounds for a 5.1 setup. I've got a very modest JBL DCR600 receiver (yes, JBL receiver). It is very similar to some lower end Harmon Kardon receivers from ~ 2005. Supposedly 75W per channel into stereo. That being said, it's really an over-achiever for the ~$400 I spent for the 5.1 system with receiver. It allowed me to upgrade speakers without having to upgrade electronics for quite a while.

This receiver has a fixed crossover frequency of 100Hz as it came with some rather small satellite speakers (3" woofer and .5" tweeter). I've measured the crossovers. The lowpass is 4th order at 100 Hz. The highpass is 2nd order at 100 Hz. This is a good config if your speakers have 2nd order rolloff at 100 Hz but mine don't. I'll be looking for a new receiver soon.

I'm measuring with a Radio Shack analog SPL meter into REW using the calibration curve for the meter provided on this forum. I'm only measuring to 2kHz because of the Radio Shack meter. I'm also using a calibration curve for my Realtek onboard sound, which is not too bad but certainly not as good as the M-Audio Revolution card I had in my old system.

The left front speaker is 142 inches or about 3.6 meters from the listening position. Pictures of the room are shown below...

Here you can see the basic room layout. It has an open ceiling to the 2nd floor and open walls to the kitchen and upstairs.

 

towards the LP
 

from the LP
 

from the screen

 

upwards from the screen. You can see all the shutters that are giving me fits with vibration...

 

view from above...

 

So I calibrated the Radio Shack SPL meter in the 90 dB setting because I get clipping at 100 dB with the meter in the 80 dB setting. Here I had to reduce my input level setting so that my maximum SPL measurement was high enough per the REW calibration instructions. (mmm, see REW documentation)

After calibration, the meter was not touched nor were the settings in REW. I progressively increased the volume level by 3 dB settings on the receiver (taking measurements at each increment) until I thought I had reached compression of the system (i.e. non-linear SPL increase with power).

The figure below shows the results of my testing for the Klipsch RF-82 in my room with speakers set to small on my AVR.

 

Hmm, it might be hard to read, see attachment it's much bigger. I think it shows compression of the waveform above 100 Hz at about 105 dB in this system. Signals below 100Hz don't seem to compress which is likely a result of the 100 Hz high pass for the mains when set to small. I think compression above 100 Hz is a result of lack of power from my very budget AVR. The last two curves are +6dB and +9dB on the AVR. I think the +9dB curve is clipping. I think this is close the reference level at my LP (about 3.6m). Very good for budget speakers (I got them for $500/pair) and a very budget AVR. Anyway, I'd like to hear peoples interpretation of these results. 

I'd like to see more tests of this nature (better technically than mine) that show what it takes for speakers to hit reference levels. These Klipsch are very efficient and I think they can get there. Some others, not so sure. Anyhow, thanks. I'll be posting my subwoofer max SPL measurements soon in that section of the forum (DIY).

-Vann_d


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## vann_d

Here's the plot with 1/12 octave smoothing...

If I say this shows 100dB clean at 3.6m, that's theoretically about 110 dB or so at 1m. With the advertised 98 dB 1W/m efficiency, this means the receiver is putting out about 16W clean power across the frequency range...hmmm. I wonder if there is clipping going on somewhere in the measurement chain. I should be able to get about 106-107 dB if the claimed 75W into stereo is accurate. :doh:


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## Jungle Jack

Hello,
Owning to yours Klipschs efficiency, you really do not need a powerhouse of an AVR to drive them to very high SPL's. It truly is a wonderful thing and provides you with great flexibility when choosing an AVR.
Cheers,
JJ


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## vann_d

Jungle Jack said:


> Hello,
> Owning to yours Klipschs efficiency, you really do not need a powerhouse of an AVR to drive them to very high SPL's. It truly is a wonderful thing and provides you with great flexibility when choosing an AVR.
> Cheers,
> JJ


Yeah, thanks. Quite the opposite of your ML's. (although I'm sure they sound fantastic) It truly is a cool thing to know that a very budget AVR will allow me to achieve reference levels. I'm kinda looking at the Onlyo HT-RC180 from A4L as a Father's day present. I think that one will give me all I need. All the new features without the expense of a huge amp.

I know a lot of folk say they don't like the sound of Klipsch but I just don't see it in the measurements. Actually, not a lot of measurements out there. From the small amount of unsophisticated measurements that I've done in my listening room, I don't think they are off much from any other type of loudspeaker. Oh yeah, I do turn the treble control down just a bit. That's not a crime, is it?


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## Jungle Jack

Hello,
With Speakers being such a personal and subjective thing in terms of what qualities that people respond to that I always include Klipsch or other Horn Loaded Speakers such as HSU's, when someone is starting out, to Audition. And if the budget is small and the needs are large, I especially recommend them as you can use an Entry Level AVR and still get Reference Level SPL's. All I can say is that the Klipschhorn and LaScalla have been virtually unchanged for many decades.

As for my MartinLogan's, they are honestly a cruel thing to ever connect to an AVR. Rather, I use an AVR as an SSP and run Amplifiers disguised as Boat Anchors to drive them. As I live mere Miles from the Gulf of Mexico in SW Florida, it might come in handy the next Cat 4 or 5 comes this way...(literally knocked on wood)
Cheers,
JJ


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## chashint

Do you have a sub in the system ?


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## vann_d

chashint said:


> Do you have a sub in the system ?


Yeah, I have a DIY sub with a Dayton 15" HF. Here's a measurement at the LP with the sub...


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## hearingspecialist

Your towers are "toed" in quite a bit, i'm guessing your left hits your kitty in the pic pretty well and the right hits the far left side chair. Are these your main listening seats when you watch tv? With horns especially the ones used in your setup you may get a better response and much better dispersion by not having them so toed in. In fact, some horn technology is beneficial with the opposite or less toe in. As a fellow room correction/calibration nut with religous use of my Advanced MCACC, I would straighten your mains, re-calibrate then listen to your results. Use the same reference disc for before and after observations. If you taped a laser pointer from Home Depot to the top of your towers directly in the center of each enclosure and saw where they were pointing you would see some crazy action happening when those horn driven frequencies cross. Just my opinion here, you have awesome towers btw :T


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## vann_d

I subscribe to the Klipsch and Harmon international theories on toe in that suggest crossing in front of the listening position for the largest sweet spot. This approach is also suggested by many other horn loaded designs including danley an pi. From my experience, this approach performs as advertised.

I can't say that I've read any white papers suggesting the approaches you mention. Do you have any references you could point me to? I'd be interested to read the arguments for such an approach.

Oh, thanks for the compliment. Got them from Ultimate electronics for a price I couldn't resist.


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## hearingspecialist

Here's where I started but am currently searching for the article supporting my thought from the Audio Engineering Society. It may take me some time to find it again : )

Horn/Tractrix technolgy and theory: http://fullrangedriver.com/singledriver/horninfo.html


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## vann_d

Cool thanks. Lots of good resources there. Some I'm already familiar with. The few that are linked on the page seem to support the approach I'm using I think. I'll try to check some of the others out. Let me know if you find the one you were thinking of!


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## Jungle Jack

Hello,
After spending countless hours positioning my MartinLogan Vantages, I did end up Toeing them in. It is actually recommended in the Owners Manual for my speakers. I realize the Electrostatic Panel Hybrid and full Electrostatic's are different than conventional speakers in that their Vertical Dispersion is not nearly as good.

Using a Center Channel does help greatly to fill in the sound in my Room which is larger than some. ML's Center Channel Speakers are strange in that they use a Panel for the Midrange, Soft Dome Tweeter for the Highs, and a Woofer for the bottom of the Frequency Response. Only the Logos, which was ML's first CC, used a Panel for the entire Design. Some covet it for that explicit purpose, but output was severely compromised as Center Channel Speakers on the whole tend to be much smaller to accommodate placement as close to the Display as possible.

ML's Theater was a much larger CC than even Stage that is ML's current flagship CC. The Stage is actually not much larger than the Cinema, but greatly benefits from the Xstat Panel which provides with a great deal more output than a Gen II Panel of comparable size. Secrets of Home Theater and High Fidelity actually deemed the Stage one of the finest CC's they have ever Reviewed.
Here is the Review for those interested: http://www.hometheaterhifi.com/home...artinlogan-home-theater-system.html?showall=1
Cheers,
JJ


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## nyt

Hi, just thought I'd add something here.

I see you are estimating power usage based on Klipsch's rated efficiency. Klipsch overrates these by a good deal. I have a pair of RF83s and can confirm that as well. If you want to know your actual power usage, hook a volt meter up to the terminals. You can then calculate wattage by using the formula w = v^2/r.

That being said, the Klipsch speakers are still more efficient than most other tower designs.


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## vann_d

nyt said:


> Hi, just thought I'd add something here.
> 
> I see you are estimating power usage based on Klipsch's rated efficiency. Klipsch overrates these by a good deal. I have a pair of RF83s and can confirm that as well. If you want to know your actual power usage, hook a volt meter up to the terminals. You can then calculate wattage by using the formula w = v^2/r.
> 
> That being said, the Klipsch speakers are still more efficient than most other tower designs.


Good point. But I think to do this correctly I'd need to know the frequency dependent impedance function and not just the nominal value. At any rate, I get your point.

100dB at LP is still good from my wimpy receiver . I'm not allowed to listen that loud anyway...


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## tesseract

vann_d said:


> I subscribe to the Klipsch and Harmon international theories on toe in that suggest crossing in front of the listening position for the largest sweet spot. This approach is also suggested by many other horn loaded designs including danley an pi. From my experience, this approach performs as advertised


I agree, keep doing what you are doing. Geddes, LeJeune and Parham all recommend the 45 degree toe in with constant directivity speakers.


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## tesseract

Jungle Jack said:


> As for my MartinLogan's, they are honestly a cruel thing to ever connect to an AVR. Rather, I use an AVR as an SSP and run Amplifiers disguised as Boat Anchors to drive them.


I have lusted after that model of boat anchor for years. If you ever decide to sell, lemme know!


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## tesseract

hearingspecialist said:


> Here's where I started but am currently searching for the article supporting my thought from the Audio Engineering Society. It may take me some time to find it again : )
> 
> Horn/Tractrix technolgy and theory: http://fullrangedriver.com/singledriver/horninfo.html


hearingspecialist - check this out, with constant directivity speakers, side wall reflections are a _good thing_. :T

http://www.pispeakers.com/Pi_Speakers_Info.pdf


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## Jungle Jack

tesseract said:


> I have lusted after that model of boat anchor for years. If you ever decide to sell, lemme know!


Hello,
Will do. I even have a brand new set of Panels for the Vantages that have never been installed. I got them as there was a deviation between the Left and Right Channel of 1.5 Decibels that turned out to be my Amplifier causing it.

As I have the Boxes for everything, it would be possible to Ship them, but I don't even want to know how much Shipping would cost as the Boxes for the Vantages and Vistas are so large that I Rented a Chevrolet Tahoe to get the Vantages and with all of the Seats down, they barely fit in the Truck.

While I love my Speakers, I often think of switching to Focal Maestro Utopia BE's, Dynaudio Confidences, Thiel CS 3.7's, Revel Ultima Salon 2's, and B&W 802 Diamond for my Mains. Especially with the Focals, the cost of upgrade is around the same as a nice used Porsche 911, but you only live once and the Focals are so utterly engaging that it just might be worth it. $50,000 Dollars for a pair of Speakers is pretty insane and I might even have to upgrade from my Aragon 8008bb to get the best out of them, but again you only live once...
Cheers,
JJ


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## hearingspecialist

Yep, I had no idea what I was thinking and can't for the life of me remember what I was reading so I must regress and apologize for my mentioned comment. No excuse, I just can't remember and I should have waited to source document before responding...dang my bad luck :bigsmile:


No soup for me...addle:


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## vann_d

No worries. Glad to get positive feedback which stemmed from your question.

I must attest that the stereo image at the far right seating position is still good with this toe in. Much better than when pointed straight.


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## tesseract

Jungle Jack said:


> and I might even have to upgrade from my Aragon 8008bb to get the best out of them, but again you only live once...



The Aragon 8008bb was the boat anchor I was referring to, not the ML's.  Always wanted one of those, even the 4004 would do. 

First, like yourself, I am looking at new speakers. I would very much like to try constant directivity, but I have no wall at all on one side of my difficult room. Maybe it will work anyway, just can't toe them in at 45 degrees.


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## Jungle Jack

Hello,
Sorry. I was not firing on all cylinders the other day. It might be difficult to get me to sell the Aragon as I absolutely adore it. I could not recommend high enough any of the pre-Klipsch Aragon Amplifiers and the 8008MKII and Palladium post-Klipsch.
Cheers,
JJ


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