Revel M16 Speaker Review

[BurgerCheese]

Problem with this speaker is with distorion, not with that insignificant peak around 5100Hz at on-axis response.

That we can agree on. The peak at 5 kHz isn't an issue by itself, but it gives a strong indication to what causes the distortion in the midrange.

 

[BurgerCheese]

Pretty sure this horse is glue now.

Point taken.

 

[Frank Dernie]

You seem to fail to realize that cone breakup will (usually) only be visible in the frequency response on-axis. And it is visible, the shape of the on-axis peak even looks like the distortion peak!

You can't see the peak in the predicted in-room response because any 6" cone obviously has limited off-axis response at 5kHz, not to mention that the cone will have all sorts of extra phase cancellations due to the cone breakup. Just look at the data sheet for any random metal woofer.

Isn't it the case that the beaming at high frequencies is only in the pistonic range of the speaker?
My understanding of breakup is that it resulyts in radiation in multiple directions.
I haven't worked on this myself but a friend worked on the NXT and BMR driver prototypes and the idea was to harness "break up" to radiate at higher frequencies. When the panel or BMR "goes modal" it is tuned, by masses and off centre drive coil, to have very many modes of similar amplitude, rather than a small number of very strong ones. One of the features of the BMR is that in the modal range it radiates over a very wide angle.
So based on that I would not expect a peak due to cone break up to have narrow radiation, in fact one of the ways one could deduce it was breakup would be the radiation widens as it does in drivers designed that way.

 

[QMuse]

Isn't it the case that the beaming at high frequencies is only in the pistonic range of the speaker?
My understanding of breakup is that it resulyts in radiation in multiple directions.

Exactly my thoughts. Now who would expect that we will agree on resonance matter..

 

[617]

Isn't it the case that the beaming at high frequencies is only in the pistonic range of the speaker?
My understanding of breakup is that it resulyts in radiation in multiple directions.
I haven't worked on this myself but a friend worked on the NXT and BMR driver prototypes and the idea was to harness "break up" to radiate at higher frequencies. When the panel or BMR "goes modal" it is tuned, by masses and off centre drive coil, to have very many modes of similar amplitude, rather than a small number of very strong ones. One of the features of the BMR is that in the modal range it radiates over a very wide angle.
So based on that I would not expect a peak due to cone break up to have narrow radiation, in fact one of the ways one could deduce it was breakup would be the radiation widens as it does in drivers designed that way.

This is correct. If one side of the cone is out of phase with the other side, the directional effects ("beaming") will be different and almost certainly wider. BMRs have a miraculously wide dispersion, exceeding what a pistonic driver is capable of. See this 35mm unit with better treble dispersion than many small tweeters:

I suppose there is some transition frequency where the BMR stops being pistonic and starts acting as a BMR, but I don't know where it is.

 

[hardisj]

See this 35mm unit with better treble dispersion than many small tweeters:
<snip>

I suppose there is some transition frequency where the BMR stops being pistonic and starts acting as a BMR, but I don't know where it is.

Hey, I recognize that.

 

[ex audiophile]

I'm a big fan of Revel speakers and coughed up the $$ for a pair of 228be mains. I've been looking at reviews of the bookshelf version (126be) and just had to share this as an example of the reviews most people are used to (in contrast to Amir's reviews). It's from Absolute Sound.

"the M126Be is more about a continuous musical embroidery of naturally scaled images within an ambient sound space. This is exactly what I got as I listened to Diana Krall’s “I’ll See You in My Dreams”—there was the sense of sitting-in with the band, feeling the wash of ambience energizing the space, the excellent upper-bass pitch definition, and the bouncy steel-string guitar solo that breaks from the speaker within its own acoustic pocket. "

Hard to describe the reaction to that bit of nonsense. What would a "non ambient sound space" be like

And btw I found the anti-Krall voice I've been looking for in Lucinda Williams. Especially in 6 blocks away her voice makes me think of an older Janis Joplin, some rasp, some slur. 6 blocks away is a fun song and if you turn it up to at least 80 db the final 60 seconds is just the band "let loose" and leaves you with those little skin tingles we all love.

 

[Juhazi]

More info
https://www.klippel.de/fileadmin/kl...ement_and_Visualization_Cone_vibration_06.pdf
https://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Loudspeaker Nonlinearities_Causes,Parameters,Symptoms_06.pdf

https://www.klippel.de/fileadmin/_migrated/content_uploads/KLIPPEL_Sound_Radiation_Poster_01.pdf
https://www.klippel.de/fileadmin/_migrated/content_uploads/KLIPPEL_Cone_Vibration_Poster_01.pdf

 

[617]

More info
https://www.klippel.de/fileadmin/kl...ement_and_Visualization_Cone_vibration_06.pdf
https://www.klippel.de/fileadmin/klippel/Files/Know_How/Literature/Papers/Loudspeaker Nonlinearities_Causes,Parameters,Symptoms_06.pdf

Excellent information and diagrams, good find.

 

[jhaider]

Without providing any actual arguments to support that certainty.

I had the same misunderstanding you're demonstrating at one point. The following exchange may be illuminating for you.

Put another way, the third harmonic is a signal. That signal is then amplified by the breakup. The resulting distortion at H1 thus appears to be higher.

 

[Shazb0t]

My second audio equipment, with which I experiment, has a very contained cost. Amplifier (second-hand € 115) + bookshelves (€ 398) + DAC + cables + improvements in that hard < € 700 € 750

Updated: and about € 300 more to mitigate the terrible power grid that I suffer in my area thanks to the electric company, the biggest / worst bottleneck I have in my two systems.

After reading many examples of Your and Danny's advice I also improve my fifth audio equipment, which has A very contained cost. I Hack off the back of speaker with saw and make open baffle. Open baffle sound much more spacious and clear.

At only cost of $7.98 (each) hacksaw improve sound so people across the street hear much detail and openness. Night and Day!!

 

[maty]

The change when reproducing an orchestral mass is abysmal. The first time you hear it with OB you never forget it! Of course, large DIY OB loudspeakers supported with two DIY 18" closed subwoofer and... a very Big room (that is the usual problem).

 

[Frank Dernie]

This is correct. If one side of the cone is out of phase with the other side, the directional effects ("beaming") will be different and almost certainly wider. BMRs have a miraculously wide dispersion, exceeding what a pistonic driver is capable of. See this 35mm unit with better treble dispersion than many small tweeters:

View attachment 53071
I suppose there is some transition frequency where the BMR stops being pistonic and starts acting as a BMR, but I don't know where it is.

Whilst I was consulting for Lola Cars in Huntingdon 3 days per week the engineer doing the computation and testing of the NXT and BMR drivers for NXT stayed in the same B&B and we became good friends.
I listened to prototypes which were very impressive.
The limitation of NXT panels was size and the difficulty with BMR drivers is consistency in manufacture.
With a conventional driver the glue quantity and overlap of the surround join to the cone is not super critical but on a BMR it has a big influence on the higher modes. IIRC the big difficulty wasn't producing a superb unit, it was producing two the same in a factory used to make conventional drivers.
The translation from pistonic to controlled modal radiation is calculated. The engineering is clever with small asymmetries to make sure there are a lot of modes not a few.

 

[LTig]

When the sound difference is so large, no measurement is necessary.

Uh huh.

 

[bobbooo]

All 9 curves are true independent variables and are specific to the speaker been tested. There is no border angle from which curves magically become independent but are dependent with lower angles. Sure, with quality speakers all 9 curves used to calculate LW would be similar to on-axis, but that doesn't mean that LW is the same thing as on-axis curve as LW does contain 8 additional spatial information which on-axis curve doesn't have. this being much mroe valuable.

So even if both curves measure exactly the same they still don't provide the same information.

You're conflating 'independent variables' with 'variables that are statistically independent of each other', the latter I probably should have written instead of 'true independent variables'. Although widespread in its use, I (and a lot of researchers, scientists etc.) am not a big fan of the term 'independent variable' as it can cause confusion like this - perhaps 'explanatory variable' is a better term.

I never claimed there is a 'border angle' at which statistical independence between the LW curves arises or disappears as a discrete effect. The multicollinearity of the off-axis curves with the on-axis response (the statistical correlation between them) is a continuous variable, that is likely higher the smaller the angular difference is from on-axis. Dr. Sean Olive explains the collinearity of all the possible variables that could make up his preference formula in his AES paper, with a 'correlation circle' of the variables for his first study showing that the narrow-band deviation and slopes of the on-axis and LW curves are quite highly and very highly correlated respectively. Looking at Amir's and many others' directivity measurements it's quite apparent that smaller angles from on-axis show a statistically higher correlation with the on-axis response than larger angles. I also didn't say 'LW is the same thing as the on-axis curve' (the difference between them actually provides some useful information about the directivity of the speaker). All I'm saying is there's a high statistical correlation between them, so claiming that looking at the LW helps to infer the PIR but looking at the on-axis response doesn't is incoherent.

 

[Deleted member 9286]

You lot are cone obsessed.......reminds me of another *ahem* website I visit

 

[edechamps]

that doesn't mean that LW is the same thing as on-axis curve as LW does contain 8 additional spatial information which on-axis curve doesn't have. this being much mroe valuable.

The "8 additional spatial information" is not necessarily a good thing, because LW is an average. Just like frequency response smoothing can be misleading, spatial averaging can be misleading too. In particular, it can make variations at individual angles appear smaller than they really are.

Consider this: there could very well be frequency response anomalies that shift in frequency depending on angle, because they are related to the difference in distance between speaker elements (e.g. interference, diffraction). That's a real problem that could be audible, just not always at the same frequencies depending on what specific angle you happen to listen at right now. But because of the way the averaging works, if you take the average of multiple angles where the anomalies are not aligned in frequency, you might get a response that looks much flatter than any actual response you can get at any angle.

That's not to say that the opposite, that LW is meaningless, is true, of course. LW is useful because it can tell you if some feature at a given frequency in the on-axis response is specific to the 0° angle or if it persists over small angles as well, which is useful information especially if you want to determine what kind of anomaly you are looking at (resonance, interference, diffraction, etc.). That's why the standard spinorama includes both on-axis and LW; one is not "better" than the other, they serve different purposes and it's really the combination of the two that's most useful, not one in isolation.

 

[stren]

So let's say the breakup is because the woofer is being pushed too far. Presumably if we assume subs as needed to handle the low end then the F35 with multiple 5" drivers might avoid this issue and pushes just as low for 3dB and lower for 10dB (according to revel's specs)? Of course the crossover point is now 1.8KHz so maybe now the tweeter might be pushed too far...

 

[infinitesymphony]

Speaking of subwoofer augmentation, how long until we start seeing those measured? I'm sure the low directivity with low frequencies will make this difficult, along with the necessary room size (e.g. following the half-wavelength theory you would need a room >= 28.25' for 20 Hz).

 

[Spocko]

I'm a big fan of Revel speakers and coughed up the $$ for a pair of 228be mains. I've been looking at reviews of the bookshelf version (126be) and just had to share this as an example of the reviews most people are used to (in contrast to Amir's reviews). It's from Absolute Sound.

"the M126Be is more about a continuous musical embroidery of naturally scaled images within an ambient sound space. This is exactly what I got as I listened to Diana Krall’s “I’ll See You in My Dreams”—there was the sense of sitting-in with the band, feeling the wash of ambience energizing the space, the excellent upper-bass pitch definition, and the bouncy steel-string guitar solo that breaks from the speaker within its own acoustic pocket. "

Hard to describe the reaction to that bit of nonsense. What would a "non ambient sound space" be like

And btw I found the anti-Krall voice I've been looking for in Lucinda Williams. Especially in 6 blocks away her voice makes me think of an older Janis Joplin, some rasp, some slur. 6 blocks away is a fun song and if you turn it up to at least 80 db the final 60 seconds is just the band "let loose" and leaves you with those little skin tingles we all love.

Unfortunately, I live in a non-ambient sound space and yet, I'm also hearing the continuous musical embroidery from my m126be! So much so that my dog came in from the backyard to sit by the foot of my chair to stare, jaw agape.