Revel M16 Speaker Review

[hawk01]

will certainly keep the EQ resources in mind! for the time being the old reliable “rolled up sock in the port” is my quick fix in taming the unwanted bass spikes. being a total newbie requires a bit of a learning curve on my part. i already began reading up on minidsp setup as per @amirm post.

 

[dominikz]

Recently I was playing a bit with speaker measurements so I've measured the quasi-anechoic on-axis response of my pair of Revel M16s. Since there are two independent sets of spins available for it (ASR and Revel's own), I found this exercise interesting as it's possible to validate the data quite nicely.
The methodology (gated far-field HF response spliced/blended with baffle-step-compensated nearfield LF response) is based on the whitepaper by Jeff Bagby and this blog post by Archimago.

Let me start with a question to those more experienced with speaker measurements and design. When attempting to scale the port nearfield measurement level to appropriately match the woofer level, there is a need to calculate the effective radiating surface for both the woofer and the port, and scale the response based on their ratio. If both the woofer and port are round, we can calculate the approximate radiating surfaces by using the generic circle area formula, as long as we have the appropriate diameters.
- For the woofer we measure the approximate effective radiating diameter using middle-of-surround as start and end point
- For a simple cylindrical port it is trivial to measure the effective radiating diameter (i.e. same as port diameter)
My question is what do we use for effective radiating port diameter if it is a flared port - is it the port 'throat' (narrowest point) or 'mouth' (widest point / exit) diameter?
My assumption (based on some experimentation) is that it should be port 'mouth' (widest point / exit) diameter, and this is what I used in the measurements below - but would love to have some references (or better argumentation) for this.

Anyway, these are my results:

Here the responses are separated, so the detail visibility is improved:

As far as differences go, vendor measurement shows a bit lower-Q bass hump (and approx. 1dB lower peak), while Amir's measurement shows a drop in response above 10kHz. In my measurements there is some loss of fine details in the ~300Hz-2kHz range. This is due to the nature of in-room gated HF measurements (edit: and the size of my room).
But as you see, overall there is pretty good agreement with both Amir's and Revel/vendor measurements. So it seems that unit-to-unit response consistency of Revel M16 is quite good.
A note that I don't have full confidence in the absolute level (or slope) of LF response in my measurements for the time being - mainly due to the above question on flared port effective radiating surface estimation.
Here's a diagram showing (scaled) nearfield measured components vs full on-axis response:

In-room distortion measurements (these are definitely not reliable in an absolute sense, mainly due to room influence). We see the same slight rise in distortion before the crossover. Absolute level:

Normalized to fundamental:

Anyway, hope this might be interesting to some - if nothing else, it is one more independent dataset

 

[YSC]

Recently I was playing a bit with speaker measurements so I've measured the quasi-anechoic on-axis response of my pair of Revel M16s. Since there are two independent sets of spins available for it (ASR and Revel's own), I found this exercise interesting as it's possible to validate the data quite nicely.
The methodology (gated far-field HF response spliced/blended with baffle-step-compensated nearfield LF response) is based on the whitepaper by Jeff Bagby and this blog post by Archimago.

Let me start with a question to those more experienced with speaker measurements and design. When attempting to scale the port nearfield measurement level to appropriately match the woofer level, there is a need to calculate the effective radiating surface for both the woofer and the port, and scale the response based on their ratio. If both the woofer and port are round, we can calculate the approximate radiating surfaces by using the generic circle area formula, as long as we have the appropriate diameters.
- For the woofer we measure the approximate effective radiating diameter using middle-of-surround as start and end point
- For a simple cylindrical port it is trivial to measure the effective radiating diameter (i.e. same as port diameter)
My question is what do we use for effective radiating port diameter if it is a flared port - is it the port 'throat' (narrowest point) or 'mouth' (widest point / exit) diameter?
My assumption (based on some experimentation) is that it should be port 'mouth' (widest point / exit) diameter, and this is what I used in the measurements below - but would love to have some references (or better argumentation) for this.

Anyway, these are my results:
View attachment 95240
Here the responses are separated, so the detail visibility is improved:
View attachment 95241
As far as differences go, vendor measurement shows a bit lower-Q bass hump (and approx. 1dB lower peak), while ASR measurement shows a drop in response above 10kHz. Also, in my measurements there is some loss of fine details in the ~300Hz-2kHz range. This is due to the nature of in-room gated HF measurements.
But as you see, overall there is pretty good agreement with both ASR and Revel/vendor measurements. So it seems that unit-to-unit response consistency of Revel M16 is quite good.
A note that I don't have full confidence in the absolute level (or slope) of LF response in my measurement for now - mainly due to the above question on flared port effective radiating surface estimation.
Here's a diagram showing (scaled) nearfield measured components vs full on-axis response:
View attachment 95244

In-room distortion measurements (these are definitely not reliable in an absolute sense due to room influence). We see the same slight rise in distortion before the crossover. Absolute level:
View attachment 95245
Normalized to fundamental:
View attachment 95246

Anyway, hope this might be interesting to some - if nothing else, it is one more independent dataset

nice exercise! it seems like having a 70hz cancellation due to back wall reflection? and a boost around 160-200hz where Genelec said is a common Desktop boost.

 

[dominikz]

nice exercise! it seems like having a 70hz cancellation due to back wall reflection? and a boost around 160-200hz where Genelec said is a common Desktop boost.

Thanks!
Regarding your questions, I guess you are looking at the 1st distortion graph, fundamental plot.
At the measuring position the back wall was ~80-90cm from the back of speaker (so 70Hz should be half-wavelength cancellation frequency - well noticed ), microphone was ~1m from the tweeter, tweeter and mic were ~1,2m above the floor (with some absorption material on the floor between the mic and speaker) - so I'm not really sure where the 160-200hz boost came from.

 

[YSC]

Thanks!
Regarding your questions, I guess you are looking at the 1st distortion graph, fundamental plot.
At the measuring position the back wall was ~80-90cm from the back of speaker (so 70Hz should be half-wavelength cancellation frequency - well noticed ), microphone was ~1m from the tweeter, tweeter and mic were ~1,2m above the floor (with some absorption material on the floor between the mic and speaker) - so I'm not really sure where the 160-200hz boost came from.

Ah alright, I was thinking did you put them on a desk or something, but if it’s on a stand then maybe it’s the full wavelength boost from back wall reflection same as the 70hz cancellation. Any suggestions from revel about minimum distance from back wall needed? I am actually curious of say put around 5cm as suggested by genelec and see if the overall FR will be better or not

 

[dominikz]

Ah alright, I was thinking did you put them on a desk or something, but if it’s on a stand then maybe it’s the full wavelength boost from back wall reflection same as the 70hz cancellation. Any suggestions from revel about minimum distance from back wall needed? I am actually curious of say put around 5cm as suggested by genelec and see if the overall FR will be better or not

Speakers were on a case right at the edge of a table when measuring, so you were not off by much in your assumption . Since the table surface was close to the back side of the speaker, I guess it could be the desk together with the back wall caused this constructive interference between 160-200Hz.

Regarding positioning, Revel just say to move the speakers 'farther' from back and side walls, without being specific. In my actual living room listening position they are maybe ~15cm from the back wall and the response definitely looks quite different. I'll try to do an average in-room response across the listening position (couch) for comparison and post that as well.

 

[dominikz]

Ah alright, I was thinking did you put them on a desk or something, but if it’s on a stand then maybe it’s the full wavelength boost from back wall reflection same as the 70hz cancellation. Any suggestions from revel about minimum distance from back wall needed? I am actually curious of say put around 5cm as suggested by genelec and see if the overall FR will be better or not

Now I measured the in-room response at the listening position. This is an RMS average of in total 18 measurements - for each speaker 9 measurements at various points across the listening position (or "living room couch", as we like to call it informally ):

As you can see, we have some bass bloom between 50-200Hz, and a fairly large null around 67Hz.
Here's a close-up of that:

So the peak at ~54 Hz is a room mode (width), and I the null at ~67 Hz is another one (height). The rest is anybody's guess - the REW model is based on a simple rectangular room, and our's is neither sealed nor fully rectangular
I played a bit with EQ to try and tame that, but decided in the end that with the usual SPL level we listen at (think residential apartment building) it's actually even pleasing to have this bass boost - it's like a natural loudness effect
It can get much when we turn up the volume a bit, though.

Overall I must say I'm quite happy with these!

 

[BYRTT]

Thanks @dominikz share your good work here, looks nice and establish tailwind that @amirm analyze for low end is better than manufacture for this one, extreme of top octave deviate some though.

 

[dominikz]

Thanks @dominikz share your good work here, looks nice and establish tailwind that @amirm analyze for low end is better than manufacture for this one, extreme of top octave deviate some though.

View attachment 95344

Thanks for this! These are some really cool visualizations, especially nice to see how PIR matches quite nicely to my in-room averaged measurement

Regarding low frequency response in my quasi-anechoic measurment graph, as I mentioned in the first post I'm not yet confident I'm calculating the port/woofer scaling correctly - would be great if someone could pitch-in on that!

However, it seems that the M16 spin measurement posted on Audioholics also matches Amir's better than Revel's own in the low end (though it is apparently just 1-2dB difference anyway):

Their measurement also shows a rise in response in the top octave.

 

[BYRTT]

Thanks for this! These are some really cool visualizations, especially nice to see how PIR matches quite nicely to my in-room averaged measurement

Regarding low frequency response in my quasi-anechoic measurment graph, as I mentioned in the first post I'm not yet confident I'm calculating the port/woofer scaling correctly - would be great if someone could pitch-in on that!

However, it seems that the M16 spin measurement posted on Audioholics also matches Amir's better than Revel's own in the low end (though it is apparently just 1-2dB difference anyway):
View attachment 95352
Their measurement also shows a rise in response in the top octave.

Port calculating is not my best, but IIRC you can find it if you download the ARTA user manual or maybe get in touch with member @ctrl, myself never heard a M16 but it looks great on objective spin so imagine you are a happy owner ..

 

[Bren Derlin]

Just ordered my M16s (white). Can't wait to out these through the paces.

 

[Bren Derlin]

The M16s landed today. As did their Revel stands. I unplugged my 16 year old LSi15 speakers, and plugged the M16 speakers into my 16 year old Denon AVR 3805, as it’s all I have. I’m using 14 gauge speaker wire from Monoprice.

my living room is 20x20 with an 18’ ceiling. These speakers fill this space with lush sounding music - far exceeded my expectations, considering I bought them without an audition. I half expected them to sound reasonably well compared to the M105 I heard.

I figured they wouldn’t be fatiguing, but I didn’t expect them to be this smooth. These speakers feel like they were made for David Gilmore and Pink Floyd. Lorelei and Styx. More than Feeling and Boston.

Everything I throw at them just sounds so...good. I was expecting to need a sub, but now? Hearing them in my living room? Not so much.

The M16 seem to get better with volume. They just open up and the sound stage is expansive. But, they’re surprisingly good at moderate and low volume as well. Regardless of the volume, they never sounded muddy or confused.

Srvcina. Audiomachine. Ivan Torrent. Dream Theater. Elton John. They’ve never sounded so good in my home. ...and I love my Polk LSi15. ...but I like these Revel M16 more so. And they’re fantastically smaller and lighter.

Before I heard these today, I thought I might step up to the M106 eventually. ...now? I’m not so sure. I’ve been sitting and listening to music for 2 straight hours - much to the chagrin of my wife - with a giant grin on my face.

I’m entirely happy with these. Absolutely zero buyer’s remorse. In fact, for $810, these feel like a steal.

 

[Sal1950]

These speakers feel like they were made for David Gilmore and Pink Floyd.

Well of course, Amir's measurements show how awesomely smooth these are all across the extended midrange.

I was expecting to need a sub, but now? Hearing them in my living room? Not so much.

The bump in the bass centered on 100hz should help to fill in any perceived loss in the lower bass and will also be easy to remove if you do get a sub. It's always much more desireable to subtract a bump than to try and fill in a valley when doing a eq for the bass range.
Enjoy your new speakers, they should bring you pleasure for many years.

 

[SteveJ]

Does anyone find these speakers particularly sensitive to placement height?

I stuck them on rather tall stands that I'd used for some other old speakers and they sounded fine while I was standing up. Slouching in my chair put the woofers at ear level and for me it ruined the sound. The bass was overpowering and just sounded odd, with a really hollow sound added to certain tones, almost like someone blowing over a bottle in the background. Just raising my backside up a few inches made a big improvement.

Obviously speaker placement is always important, but I've not noticed such a drastic effect caused by height with the cheaper/older speakers that I've used before upgrading to the M16s. You'd have to actually listen to notice it rather than the difference of a few inches in height being so obvious.

I've experimented a bit and unsurprisingly the height of the official stands seems optimal. Not that I'm going to pay £250 for stands when I got the speakers for £600, but at least I know what height the cheaper replacement stands need to be.

I'm glad I didn't buy them thinking that I'd place them on a shelf or mount them higher up on a wall. I've done that with cheaper powered speakers without having such an issue with the result, but I think it would ruin the sound from the M16s

 

[daftcombo]

Does anyone find these speakers particularly sensitive to placement height?

I stuck them on rather tall stands that I'd used for some other old speakers and they sounded fine while I was standing up. Slouching in my chair put the woofers at ear level and for me it ruined the sound. The bass was overpowering and just sounded odd, with a really hollow sound added to certain tones, almost like someone blowing over a bottle in the background. Just raising my backside up a few inches made a big improvement.

Obviously speaker placement is always important, but I've not noticed such a drastic effect caused by height with the cheaper/older speakers that I've used before upgrading to the M16s. You'd have to actually listen to notice it rather than the difference of a few inches in height being so obvious.

I've experimented a bit and unsurprisingly the height of the official stands seems optimal. Not that I'm going to pay £250 for stands when I got the speakers for £600, but at least I know what height the cheaper replacement stands need to be.

I'm glad I didn't buy them thinking that I'd place them on a shelf or mount them higher up on a wall. I've done that with cheaper powered speakers without having such an issue with the result, but I think it would ruin the sound from the M16s

How far do they sit from the walls?
It is more of a problem with the front wall in my opinion, which by chance appears with those speakers and not others.

 

[BYRTT]

Does anyone find these speakers particularly sensitive to placement height?...

It looks be a fine speaker and performer haven't heard them myself but maybe below detailed overview based on Amir's shared spindata can help about placement (lower left graphs is per 10º)...

 

[SteveJ]

How far do they sit from the walls?
It is more of a problem with the front wall in my opinion, which by chance appears with those speakers and not others.

There's currently about 14" between the wall and the back of the speaker. It's a small room so more than that isn't very practical.

 

[SteveJ]

As Daftcombo mentions, placement makes a difference with these speakers. The bass is exaggerated by design at around 100 Hz (to make them sound bassier) so they are likely to be bloaty if they are placed in a location that activates a room mode. Try moving them forward and back to find a more optimum spot.

I think that's definitely part of it. If I slide my chair within 4' of the speakers the bass sounds a whole lot better, slide back to about 6-8' away and it's pretty bad. I think I'll have to play around with the room layout a bit, but there are limits to what's practical - it's a home office rather than a dedicated listening room and some of the furniture is fitted and fixed.

That or use equalization/DSP. You'd have to take measurements with REW and a mic to find the room mode peaks and valleys, but with that you can precisely level them off. With DSP, I think these are one of the best bargains around. You can take advantage of the "extra" bass (in my room they go down to 45 Hz) and leave the disadvantage (possible bloatiness) behind.

That's not something I've ever really played around with, but it's about time I read up on EQ and looked at what options are available.

As far as the "hollow" sound goes, perhaps it's a null at around 1-3k Hz as shown in the graphs?

Testing with a frequency sweep, and looking at a frequency analysis of problematic bits of music in Audacity, I think the issue occurs at around 130-140Hz. If I play a frequency sweep while sitting down then it sounds odd and gets significantly louder at that point. If I play the same test standing up then the tone smoothly changes and that range doesn't stand out.

While the vertical directivity is not as good as the best speakers (or coaxial designs like those of KEF), they are pretty average, so as long as you are within 15 degrees above or below the tweeter you should be fine. (You are simply not going to get away with much more with most speakers, generally.) In the review however, Amir warns of ceiling and floor bounce, with ceiling bounce being something to particularly look out for. Having the speakers up high may make them susceptible to this. Do you happen to have low ceilings? Do you have a rug in the room?

I don't think the ceilings are particularly low, there's over 4' from the top of the speakers to the ceiling, and the room is carpeted.

 

[SteveJ]

Another (probably stupid) question, but would it be a really bad idea to run the M16s upside down, with the tweeter at the bottom?

 

[SteveJ]

I don't think my home office will ever be audiophile nirvana, but the main problem was definitely down to a room mode issue rather than anything specific to these speakers. Just setting -12db at 125hz in Foobar2K's graphic equalizer DSP has tamed the bass that I found so unpleasant on certain tracks. Obviously I'll fiddle and tweak a lot more than that, but I think these are definitely speakers I can live with.

I'd heard about room modes before, but this is the first time I've actually heard the effect they can have. For some reason I had the impression that it was something subtle that you'd only hear when carefully listening, rather than a big change to the volume at certain frequencies.

I think I've been lucky to avoid this before. Maybe having more clutter and less space actually helped to prevent that specific problem? Or maybe the speakers I was using were just so anaemic at those frequencies that I didn't notice.