Revel C52 Speaker Review and Measurements

[Absolute]

Hah, math even works with the mystics of audio! Who would have thunk?

 

[Krunok]

PIR shows a ~1 dB dip. Not much, but why not EQ it if there's no downside?

Because in your room you would probably be chasing Harman preferred response which would look something like this so you would more be bothered to reduce a peak at 1.5kHz.

 

[flipflop]

Because in your room you would probably be chasing Harman preferred response

I would be chasing the highest fidelity. Is that the red or the blue one?

you would more be bothered to reduce a peak at 1.5kHz.

You would also have to make cuts all the way down to 100 Hz if you were to follow that curve.

 

[Krunok]

I would be chasing the highest fidelity. Is that the red or the blue one?

"Highest fidelity" would probably be ideal horizontal curve, but Toole & Oleve research has shown that most listeners prefer curve similar to the blue one. Google "harman preferred listening curve" and many articles will pop up.

You would also have to make cuts all the way down to 100 Hz if you were to follow that curve.

That is entirely dependent on your personal listening preferences - you may as well like to leave it as it is between 100Hz and 1kHz as it is falling smoothly.

 

[Juhazi]

Nice to see NFS measurements of a large speaker, that match well with previous measurements!

And yes, Revel line of Harman is top!

 

[flipflop]

"Highest fidelity" would probably be ideal horizontal curve

Yes, for an anechoic measurement, not for an in-room response, which is what we're talking about.

 

[MZKM]

And here is the Predicted-In-Room response data for the ones working hard to get us the preference rating.

Here's what I got
https://docs.google.com/spreadsheets/d/1HmiGrNsTEJFe4wqdJym5I48TcWTiFTWR2ZsPuPsxx0U/edit?usp=sharing
The frequencies per band were less, so that took a while to correct.
Again, please point out any errors.

Preference Rating
SCORE: ~4.77

SCORE w/ subwoofer: ~7.62

SCORE w/ subwoofer with NBD_LW : ~7.83

 

[thewas]

"Highest fidelity" would probably be ideal horizontal curve, but Toole & Oleve research has shown that most listeners prefer curve similar to the blue one. Google "harman preferred listening curve" and many articles will pop up.



That is entirely dependent on your personal listening preferences - you may as well like to leave it as it is between 100Hz and 1kHz as it is falling smoothly.

We shouldn't forget that not every room has not the same absorption/reverbance frequency curve, so the calculated PIR will never be the same with the real actual one. In that case equalizing above the Schröder frequency can deform the previously linear direct sound, which will sound less neutral due to our psychoacoustic perception.

 

[Thomas_A]

Thanks amirm. Very good information - now there should be no doubts about the system.

 

[Krunok]

Yes, for an anechoic measurement, not for an in-room response, which is what we're talking about.

I already answered - harman listener preferred target curve was found to be preferred for in-room response.

 

[Krunok]

We shouldn't forget that not every room has not the same absorption/reverbance frequency curve, so the calculated PIR will never be the same with the real actual one.

Sure, modes of his garage would mess up with the response probaly up to 300 Hz and north of that it would probably be pretty flat with roll-off at HF if measured at 1m distance. Here is how it loks with my Harlech S2 when I put it in the middle of the room and measure with single on-axis sweep at 1m distance:

In that case equalizing above the Schröder frequency can deform the previously linear direct sound, which will sound less neutral due to our psychoacoustic perception.

Precise in-room measurement is a critical assumption for every room EQ. With slight adjustments (1-2dB of magnitude adjustment and with Q of 1-2) you are simply adjusting to your preferred listening curve. IME it sounds better than without it. Best automatic room EQ software (Acourate, Audiolense, Dirac, ..) do the same.

 

[thewas]

Precise measurement doesn't necessary mean much at a listener position above Schröder frequency when we are measuring quasi-static soundfields full of peaks and dips due to local reflections and modes. Our hearing and brain there don't work as an quasi-omnidirectional microphone with a measurement window of i.e. 500 Hz but weighs more the direct sound, see also the posts of Floyd Toole
https://www.avsforum.com/forum/89-s...aster-reference-monitor-143.html#post57291428
https://www.avsforum.com/forum/89-s...aster-reference-monitor-143.html#post57293354

It is essential to note that this is the room curve that would result from subjectively highly-rated loudspeakers. It is predictable from comprehensive anechoic data (the "early reflections curve in a spinorama). If you measure such a curve in your room, you can take credit for selecting excellent loudspeakers. If not, it is likely that your loudspeakers have frequency response or directivity irregularities. Equalization can address frequency response issues, but cannot fix directivity issues. Consider getting better loudspeakers. Equalizing flawed loudspeakers to match this room curve does not guarantee anything in terms of sound quality.

When we talk about a "flat" frequency response, we should be talking about anechoic on-axis or listening window data, not steady-state room curves. A flat room curve sounds too bright.

Conclusion: the evidence we need to assess potential sound quality is in comprehensive anechoic data, not in a steady-state room curve. It's in the book.

and in more detail his (free to read) AES Paper http://www.aes.org/e-lib/download.cfm/17839.pdf?ID=17839

The good thing is that loudspeakers with linear on axis response and smooth directivity behaviour create similar listening position curves which can have though different slopes depending on the room absporption behaviour and directiviy function of the loudspeaker. Equalizing above Schröder frequency to a random target curve is than just a wide tone control and thus personale taste, but not necessarily neutral, which is neutral direct sound.

That's why also good room correction tools try to weight more the direct sound in that region either by time windowing (for example Acourate) or spacial averaging (like Dirac), which I both own but after years of tests I barely touch with good speakers the higher frequencies.

 

[rajapruk]

Wonderful!
But I am still very worried that you might be positioned some slight offset relative the sea level?? (Just kidding!)

 

[Krunok]

The good thing is that loudspeakers with linear on axis response and smooth directivity behaviour create similar listening position curves which can have though different slopes depending on the room absporption behaviour and directiviy function of the loudspeaker. Equalizing above Schröder frequency to a random target curve is than just a wide tone control and thus personale taste, but not necessarily neutral, which is neutral direct sound.

When you apply gentle EQ in the range above 600Hz you are exactly compensating for room absorption/directivity charactetistic of the speaker. I don't see anything bad in that and I also don't see why it would sound "unnatural", and you don't seem to provide any argument for such claim. Is it a matter of your personal taste?

Btw, Harman preferred listener curve is not really a "random target curve". Or do you think it is?

 

[KxDx]

Revel is the real deal...

I had a pair of F30 towers and they were breathtaking. If they had had dual 10" woofer's instead of single I would have kept them for sure. But my goodness could those things sing. I've told my best friend that if he ever decides to not keep them I will buy em back.

 

[KxDx]

'Twas a bittersweet day...

 

[Blumlein 88]

Here's what I got
https://docs.google.com/spreadsheets/d/1HmiGrNsTEJFe4wqdJym5I48TcWTiFTWR2ZsPuPsxx0U/edit?usp=sharing
The frequencies per band were less, so that took a while to correct.
Again, please point out any errors.

SCORE: ~4.73

SCORE ignoring LFX: ~7.58

Am I remembering right that the max score is a 9? As the center speaker wouldn't be expected to carry much bass the 7.58 would be a good result.

 

[thewas]

When you apply gentle EQ in the range above 600Hz you are exactly compensating for room absorption/directivity charactetistic of the speaker. I don't see anything bad in that and I also don't see why it would sound "unnatural", and you don't seem to provide any argument for such claim. Is it a matter of your personal taste?

As said, above than 600 Hz the perceived tonality almost fully depends on direct sound as our brain adapts to the room acoustics, thats why "George" still sounds to us like "George" and not "Keith", a nice example that Toole uses it that noone would ever get the idea to EQ live voices or instruments in according to some listening position measurements. Its all written in above posted links or in even more detail in Toole's book

Btw, Harman preferred listener curve is not really a "random target curve". Or do you think it is?

It is (this one is an average of usual listening rooms and classical hifi loudspeakers with increasing directivity to high frequencies) as it depends as said on the directivity pattern of the loudspeaker and the reverbation characteristics of the room. As an example, an linear omindirectional loudspeaker would create a flat listening FR if the room reverbation over the frequency is constant, same also any neutral loudspeaker in an anechoic room, trying to "correct" such response to a decreasing target curve would make them sound not tonally correct.

 

[BYRTT]

Review looks qualify the new NFS is a good investment to reference, thanks amirm share your delicious HT speakers.

"On axis" and "Sound power DI" overlaid on a 50dB scale, black=NFS, purple=Anechoic:

 

[MZKM]

Am I remembering right that the max score is a 9? As the center speaker wouldn't be expected to carry much bass the 7.58 would be a good result.

A max of 9 would mean LFX cut-off for best score would be ~25Hz, so I don't think that's correct. Unless it's not programed for 0 for NBD and 1 for SM to exist.