Revel F228Be Review (Speaker)

[Ata]

It's true that there is a slight Revel bias(other than the 708p, I don't really see evidence for a JBL or Infinity bias) when looking at it objectively. Revels do receive more a subjective praise, despite measuring worse than Neumann, Genelec, KEF(?). I'm not sure I'd call it "bias", though. Is it "biased" to praise a speaker more that you like more? isn't that just being honest? I think it's important to remember that the subjective portion(and panther score) are not based on what measures the best, but what sounds the best to Amir's ears. Amir rates Revels subjectively higher than KEF, ELAC, Genelec, and Neumann because they sound better than those speakers to him. Yes, Revel speakers don't measure quite as well as some of those other brands, but they get a higher panther score(and more subjective praise) because Amir subjectively likes them more. Key word there is subjectively.

For the KEF R3 review (the passive speaker preference rating champion here?) the poor subjective review issue was an untamed room mode. Unfortunately you have to comb through the 55+ thread pages to figure that out. Now Amir is on the lookout for this kind of issue, and it was indeed a problem with F228be, too, but spotted during the review.

I asked for the R3 master post review to be edited so that this issue is put to rest.

 

[Ata]

Many of these speakers are coaxials and lower end/2-way coaxials in particular have consistently been evaluated to sound poorer than their score/measurements indicate, you're correct. There are a variety of different reasons in those reviews but I'll note better coaxials do just fine -- Amir did like the R3 and he likes the coaxial Genelecs. I suspect there are other issues in areas we don't measure. For example, Harman's blind testing has shown that IMD is a serious problem with some 2-way Kefs. And yes, that's a potentially biased source, but it's what we have.

How does one test for IMD in speakers and why isn't this done by Amir and the others in this forum?

10+ percent IMD sounds like a lot, I wonder how audible it would be? In my subjective auditioning of LS50 original vs R300 and LS50WII vs R3 I always preferred the clarity of the 3-way designs, bass response is a clear difference, but I would not be surprised if IMD was a factor.

 

[MacCali]

Honestly I just demo'd these speakers and even though they are great and measure well I am not sure what it is about speakers with larger than 5 1/4" drivers but they have this boomy crap going on that's really annoying to me. It sounds like there's literally something unnecessary in the frequency going on and adds a thump that would sound way cleaner without that in place.

I wish I knew what it was, it's not distortion. The place where I demo'd it says it's because of the ports. Yet, I have 3 speakers all ported and have 5 1/4" or less and I am getting no boomyness. It's not something that is technically bad but whenever the lower frequency's going into the air it sounds like it veils the clarity to my ears. Might be just my ears, but I experienced the very same issue when I was demoing speakers for my first purchase.

 

[aarons915]

Honestly I just demo'd these speakers and even though they are great and measure well I am not sure what it is about speakers with larger than 5 1/4" drivers but they have this boomy crap going on that's really annoying to me. It sounds like there's literally something unnecessary in the frequency going on and adds a thump that would sound way cleaner without that in place.

I wish I knew what it was, it's not distortion. The place where I demo'd it says it's because of the ports. Yet, I have 3 speakers all ported and have 5 1/4" or less and I am getting no boomyness. It's not something that is technically bad but whenever the lower frequency's going into the air it sounds like it veils the clarity to my ears. Might be just my ears, but I experienced the very same issue when I was demoing speakers for my first purchase.

It happens with any speaker that produces real bass, just as Amir mentioned in his review they excite room modes and will sound boomy if not taken care of through EQ.

 

[richard12511]

--Theres evidence that the average home listener prefers wider horizontal directivity, but also that directivity in general is preferential and not something where one style is objectively 'better' than the other. For example, mixing engineers preferring fewer sidewall reflections and mastering engineers being more okay with reflective spaces, while consumers seem to generally like sidewall reflections.

--That said, Toole seems to believe, or at least implies in his book, that a wider directivity speaker may be preferred when directivity is less even or 'pretty'. This is my experience too.

Yep, which imo adds more credence to scoring wider dispersion higher for a review. In a sense a review is kinda for the reader to give them an idea of how likely they are to prefer a speaker. If wider dispersion is on average more preferred, then it makes it more likely that speaker will be preferred by the reader.

Dispersion width is the main area where I see it as the responsibility of the reader to be aware of their own preferences compared to Amir's and interpret accordingly. If you (like me) prefer a more point source image and find it to sound more realistic, Amir's preference score may not always align with your own.

My (educated but certainly not definitive) reasoning for this is that we often look at directivity graphs and assume that the 'prettier' graph indicates the off-axis is perceived to be more similar to the direct sound. But it's not just the frequency response shape that indicates similarity to the direct sound, it's the overall SPL of those reflections too.

Likewise, narrower speakers with very good directivity tend to have a more dramatic tilt off-axis, which might look prettier in an SPL chart or polar map but in reality just means that the speaker gets increasingly dark as you move off axis, which will sound totally different from the flat line of a good listening window. A wider directivity speaker maintains its tonal tilt better off axis. It might beam more at the highest frequencies, but most directivity effects seem to happen before 10kHz.

Well said and I agree 100%. This is actually a point I've brought up a couple times before as a potential reason as to why wide dispersion might be on average more preferred. We know we want the reflections to match as closely as possible to the direct sound. Assuming "smoothness" is equal, a wider dispersion speaker's reflection is objectively closer in sound to its direct counterpart than that of a more narrow dispersion speaker.

Something I've always wondered though is where this stops being true, and how the number of channels modifies that. Theoretically an omnidirectional speaker's reflections should match most closely with the direct sound, but Revel opts not do design omni speakers. Presumably they've determined (through DBT) that at some point "reflections should match the direct sound" stops being true. I also wonder how the number of channels changes things. All the reviews I've read of the Beolab90 seem to prefer the most narrow dispersion setting(and this is B&O's recommended setting for sweet spot listening), but I wonder if that would hold true in a mono test. In my imagination, I wonder if the omni setting might actually be preferred in a mono test.

 

[richard12511]

Educated based on what?

In double blind testing, the prettiness of the off axis is most strongly correlated with preference. Not any particular directivity width.

It doesn't show up in the public test data per say, but I've seen Toole mention "wide directivity" as the second most important speaker attribute(after flat direct sound) for predicting listener preference. I presume it's something that's showed up consistently in their private data.

 

[FeddyLost]

My (educated but certainly not definitive) reasoning for this is that we often look at directivity graphs and assume that the 'prettier' graph indicates the off-axis is perceived to be more similar to the direct sound. But it's not just the frequency response shape that indicates similarity to the direct sound, it's the overall SPL of those reflections too.

Reflections' sound power will be similar to the direct sound only if RT is even enough. There might be some issues with room design and speaker placement when narrow directivity is better, but I don't have any data how often this happens.

It sounds like there's literally something unnecessary in the frequency going on and adds a thump that would sound way cleaner without that in place.

It might be group delay of very low tuned BR.
Or maybe room, treated to the point where only lowest modes left - it may give compressor-like chuffy low bass notes like low crossed subwoofer cranked up.

 

[sarumbear]

Almost every speaker on earth needs Subwoofers properly placed to round out the bottom octave, price doesn't matter.

Why? What is the difference with a 3-way speaker with a large woofer cut at low frequency and a that large woofer in a separate box?

 

[sarumbear]

I am fairly new here and am following especially the passive speaker reviews with attention. I have the highest respect for @amirm and the other objectivist's work being done here.

However, I have difficulties making sense of the listening tests and how endorsements are given.

From the SpeakerTestData one can show a statistically relevant bias in endorsements towards Revel (and JBL) speakers.
Similarly scoring KEF and ELAC speakers get (far) less endorsements even if they achieve a similar score at a far better price to performance ratio.

From what I have seen so far, it would seem that endorsements are given more on how close a speaker gets subjectively to the Revel Saloon 2 sound rather than the objective measurements.

Please note this is not intended as a critique - I'm probably wrong. Can you please help clarify?

The poster summarised it pretty well the problem with combining objective and subjective in the same review. It will never work and it doesn't work.

What we have here is an appropriately educated and very experienced person (@amirm) doing correct tests using modern equipment and publishing the results. He is basically a one man test laboratory.

He then switches to "human mode"; he listens, looks, etc. and writes his subjective views like hundreds on the Internet do. It is for us to separate the two reviews. If you are on a forum that is called Audio Science Review and still argue or debate the subjective part of a review you may ask yourself why you care to be here. It is perfectly normal and even expected to disagree with @amirm's "tastes". That is what makes him a human. However, unless you can repeat the same tests @amirm does you cannot argue with the objective results -- unless you are pointing out to a possible measurement error.

I personally only care about the tests. I do not even know where that subjective ranking table is on ASR!

 

[richard12511]

Why? What is the difference with a 3-way speaker with a large woofer cut at low frequency and a that large woofer in a separate box?

The freedom to move that woofer around the room to smooth out the response, and thus ultimately sound better.

The advantage of the 3/4 way speaker is that the sub integration is done for you, and that integration is likely better than what you'll get by simply hooking up a sub channel(or even simply running something like YPAO). It's also usually more aesthetically pleasing. Most people don't like having big black boxes scattered randomly about the room.

The downside is that the subwoofers are forcibly collocated with the rest of the speaker, which means the sound quality potential of the overall system is lower than it would be with separate and properly integrated sub units. Usually, the best place for bass in the room is not the best place for mid, treble, imaging, etc. For example, in my main room, the best spot for the L and R is about 2m out from the front wall, and 3m apart . If I let the bass play from that location(or put the subs underneath the speakers) I get some horrible and unfixable nulls in the bass response. I get a much better bass response and sound by placing one front left, 5cm from the front wall, and one back right 5cm from the back wall. Another advantage is that you can independently adjust the delays/phase of the separate woofers(which I utilize).

There are a couple exceptions I know of, though. The Grimm Audio LS1 and LS1Be have detachable woofers that can be spread around the room for optimal performance, or collocated with the mains for optimal aesthetics.

BTW, not saying you can't have good bass without external and movable subs. You can have great bass with 3/4 ways or with the subs located under the mains, just usually not as good as you can get with multiple(usually 2-4)properly integrated movable subs.

 

[Asinus]

How does one test for IMD in speakers and why isn't this done by Amir and the others in this forum?

10+ percent IMD sounds like a lot, I wonder how audible it would be? In my subjective auditioning of LS50 original vs R300 and LS50WII vs R3 I always preferred the clarity of the 3-way designs, bass response is a clear difference, but I would not be surprised if IMD was a factor.

It is measured playing two tones at the same time and checking for spurious tones at the sum and difference frequencies of the original tones and/or their harmonics. I think the audibility %-wise should be comparable to regular harmonic distortion depending on the band the extra tones are located, although it could be discriminated differently by the brain.

 

[Jbrunwa]

As others have stated, EQ with a good set of speakers will give generally good frequency response in most cases. The thing that impresses me most about the Revel line is the very low distortion measurements. The larger towers may not give much more SPL in bass but they are generally much lower distortion. I find it puzzling that some audiophiles spend big dollars driving out vanishingly small amounts of distortion in components yet will put up with distortion in their speakers. So to me, the Revel be line is worth the extra dollars.

 

[sarumbear]

The freedom to move that woofer around the room to smooth out the response, and thus ultimately sound better.

That is not the fault of the speaker though is it? You can treat your room after all...

 

[sarumbear]

The thing that impresses me most about the Revel line is the very low distortion measurements.

I'm impressed with Revel designs too. I haven't had a change to hear any Revel speaker so I cannot comment on their sound. However, unlike many, many speaker designs on the market I have not seen any design stupidity (i.e. not applying even basic physics). It looks like there is an intelligent and educated group of people behind that brand.

 

[Sancus]

How does one test for IMD in speakers and why isn't this done by Amir and the others in this forum?

10+ percent IMD sounds like a lot, I wonder how audible it would be? In my subjective auditioning of LS50 original vs R300 and LS50WII vs R3 I always preferred the clarity of the 3-way designs, bass response is a clear difference, but I would not be surprised if IMD was a factor.

It's complicated, there isn't really a standard for measuring or visualizing it, there isn't clear research on how much is audible and at what frequencies, take your pick. The THD numbers are already pretty difficult to interpret, distortion in general seems poorly understood/researched compared to frequency response. S&R publishes it, but their graph/test is hard to understand even with an explanation lol.

There is some good work on it out there, but it doesn't seem like any of it has achieved broad acceptance.

 

[napilopez]

Educated based on what?

In double blind testing, the prettiness of the off axis is most strongly correlated with preference. Not any particular directivity width.

Yes, the smoothness of the off-axis is what we know matters for preference, but it's not the only thing. Smooth directivity, which I of course think is always good to have, is generally used in the sense of the reflected sounds being similar to the direct sound. I'm just saying in addition to the 'shape' of the off-axis sound, overall SPL matters too.

Anyway, most of my 'education comes from Toole's book, but I've read most of the papers being cited. I think it's not secret that Toole is generally in favor of wider directivty/louder sidewall reflections.

Going to the research though, here's Toole in his book (7.4.2) talking about Toole (1985), a double-blind test that was specifically about directivity: "In these tests a loudspeaker with narrower dispersion, but with more uniform output off-axis, was given lower ratings than two loudspeakers with wider dispersion, but uneven output off-axis, suggesting that some amount of laterally reflected energy is desirable, even if it is spectrally distorted."

It's an old study with old speakers -- the Quad speaker here was definitely narrower than most of what we might consider 'narrower' directivity on this forum -- but still one of the best we have on this specific matter.

Relevant to @richard12511's question about how much width is optimal, a pair of studies by Klippel in 1990 found that feelings of 'naturalness' and 'pleasantness' were 50% and 70% related to spatial qualities, respectively. This study is in german so I haven't read it myself but Toole says about it(7.4.5):

"Klippel chose as his objective measure of “feeling of space” (R) the difference between the sound levels of the multidirectional reflected sounds and the direct sound at the listening location....
[snip]
...The optimum difference between the direct and reflected sound fields is about 3 dB for speech, 4 dB for a mixed program and 5 dB for music. There is no frequency dependence considered in these numbers, and we know that most loudspeakers do not exhibit constant directional behavior at all frequencies.

A good loudspeaker for this purpose would therefore be one that has two qualities: wide dispersion, thereby promoting some amount of reflected sound, and a relatively constant directivity index, so that the direct sound and reflected sounds have similar spectra."

Here's the accompanying graph:

So although these studies didn't test for the spectral quality of the reflections (the 'prettiness' of the off-axis), they do imply that all else being equal SPL alone is enough to be a contributing factor to the perceived naturalness and pleasantness of a speaker.

Toole 2006 is a great paper, a review a bazillion different studies on reflections that talks about many of the most interesting revelations in Toole's book in a slightly more analytical way. One takeaway from this study is that early reflections in a typical room happen around the zone where 'image spreading' is found, which is generally perceived as a positive effect.

Some assessment of the effects of directivity can further be inferred by studies on sidewall reflections vs absoprtion/diffusion, since it's essentially much the same thing to the listener. There have been a few studies showing reflected sounds are preferred to absorption for mastering and recreational listening.

We also know from Shirley et al 2007 stereo listening degrades speech intelligibility (although admittedly this is not the same as clarity) due to interaural crosstalk cancellation and wide directivity/louder sidewall reflections help combat this. And then I believe Toole said he thought the Salon2 beat the M2 because of the wider directivity.

It's also worth noting that the Olive preference study did not look at horizontal directivity width, it just looked at the overall DI curves, which are unreliable at describing horizontal directivity.

One could also consider the existence of the revels themselves, which consistently demonstrate wider directivity than most other speakers with prominent waveguides, with the Salon2 being particularly wide up to about 10kHz

These are just the things I could think of off the top of my head. So I don't think it's not entirely unreasonable to believe that wider directivity might be slightly more preferred for the general populace especially considering Toole seems to think along these lines too. No doubt wide and even is better.

 

[Sancus]

These are just the things I could think of off the top of my head. So I don't think it's not entirely unreasonable to believe that wider directivity might be slightly more preferred for the general populace especially considering Toole seems to think along these lines too. No doubt wide and even is better.

Or just take Toole's advice and go multi-channel, opting out of the stereo frequency response problems and the side-wall reflection dependency mess

 

[aarons915]

Why? What is the difference with a 3-way speaker with a large woofer cut at low frequency and a that large woofer in a separate box?

Well for one we're talking about 8" woofers compared to 12-18" woofers that are in most powered subwoofers, larger woofers have deeper extension. 8" Woofers are great down to about 40Hz and provide a lot of output and low distortion with an 80Hz crossover but you'll still want a sub to round them out in most cases.

 

[napilopez]

Or just take Toole's advice and go multi-channel, opting out of the stereo frequency response problems and the side-wall reflection dependency mess

Oh I'm all about multichannel listening haha. One reason I've stuck to Yamaha receivers despite their performance issues is that Cinema DSP is imo bar none the best at upmixing stereo content. But still nothing is as good as well done binaural. Too bad there's not enough of that out there...

 

[Sancus]

Oh I'm all about multichannel listening haha. One reason I've stuck to Yamaha receivers despite their performance issues is that Cinema DSP is imo bar none the best at upmixing stereo content. But still nothing is as good as well done binaural. Too bad there's not enough of that out there...

That's interesting, I haven't ever tried that, but YPAO is total garbage from all I've read, so you'd need a separate room correction solution....So far, Auro3D has served me very well and Toole really likes it as well. But it does require height speakers and the 2D version isn't nearly as good.