This is a review and detailed measurements of the Revel F35 floor-standing speaker. I purchased this through my company because there are external anechoic measurements available so we can compare. The F35 costs US $1,600 for a pair (sold each at US $800 in case you want a center speaker). It comes in black and white but the black was not in stock so I purchased white:
Fit and finish is superb. You could easily pretend to your friends you paid multiples of its cost.
Disclaimer: Before I get into this review, and at the risk of stating the obvious, I have a million conflicts of interest here. I am a long time friend and professional colleague with a number of Harman employees (parent company of Revel). I have praised their design and research philosophy countless times. And our company, Madrona Digital is a Harman dealer (although we hardly sell any stereo gear). So read all the bias you want into the review but please don't go posting to complain. Just read the measurements if you are worried and if you don't trust that, just move along.
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
All measurements are reference to tweeter axis with the grill removed. Frequency resolution is 0.7 Hz (yes, less than 1 Hz) and plots are at 20 points/octave. Spatial 3-D resolution is 1 degree.
Over 1000 points around the speaker were measured (from 20 to 20 kHz) which resulted in well under 1% error in identification of the sound field across full frequency response of 20 to 20 kHz with the exception of lowest frequencies. I think this is due to multiple drivers creating a complex soundfield. This is the first "tower speaker" I have measured on the Klippel system so we will need more data to know what we are dealing with.
Final database of measurements and data is 1.2 Gigabytes in size.
Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
As you would expect in any Revel speaker, the on-axis speaker is quite flat although not perfectly so. There are some glitches around and below 1 kHz that only showed up when I really pushed up the signal processing resolution. They don't show up in Harman anechoic measurements, nor do they show the saddle at 20 to 40 Hz. The latter I think is some kind of instrumentation error on my part per earlier explanation.
The SPL measurement is also speaker efficiency so we are talking about 90 dB which is above average in this day and age.
Predicted in-room response is very good given the nice directivity (off-axis being generally similar to on-axis especially horizontally):
I have added two key notes to the graph. The second one will become important later.
Impedance drops to near 3.5 Ohm so you need a beefy amplifier to drive this speaker:
Distortion as a percentage of output when driven with 10 volt input looks like this:
Putting aside the typical low frequency distortion, there is no other acoustic event of note.
Advanced Speaker Measurements
Early reflections which are the most audible in a typical room show that vertical reflections should be be absorbed or avoided:
Horizontal reflections are clean which you should take advantage of by NOT absorbing side walls:
Vertical reflections as noted above are not good:
So put a thick carpet on the floor. Frequency is high enough that 1 or 2 inch of absorption does the job.
You have the option of not pointing the speaker directly at you (blue for example of 20 degrees out):
Vertically based to stick with ear level which is there anyway given the height of the speaker:
Very nice horizontal spread:
Not so good vertically:
Speaker Listening Tests
Being simply the taller version of Revel M16 which I recently reviewed, I expected immediate gratification. Imagine my surprise when that did NOT happen! Detail was muddy and sound was not enjoyable reminding me of my test of KEF R3 which I just reviewed. How could this be?
We make fun of subjectivists often but hey, maybe we should listen to them sometimes. So I setup the speaker to play pink noise for 24 hours. Then I played my favorite tracks again. Wow. I could not believe my ears. All the micro-detail and detail materialized. Incredible!!!
Well, it would be incredible if the above was true but none of that is real. Where do you think we are? We don't believe in fantasties.
To borrow a line from the movie Martian, I decided to science the sh*t out of it. First I went back to KEF R3 to confirm that it had the same issue and it did. Two different speakers and the same problem? Both the R3 and F35 have more bass than M16 so how about a high pass filter? Dial one in quickly in Roon with a 6 dB decline starting at 100 Hz. Amazing. Some of the issues with R3 went away. Still not as good as the M16 but detail became better and sound fluidity improved.
Past experience with equalizing the room in low frequencies had taught me that removing bass resonances not only improves bass, but has a remarkable (good) effect on notes above that range. Resonances boost certain bass frequencies. In time domain that lengthens the amount of time it takes for those high energy notes to go away. And that steps on much lower level notes in higher frequencies.
So let's measure the room and see what we are working with (with KEF R3 on stand):
I have filtered this with 1/6 octave so there is not much clutter. Focusing below 200 Hz, we see our loudest and most offending peak is around 100 Hz. Let's dial in a single parametric filter by eye and see what does:
Beauty of Roon is that its filters can be switched on and off in a second. Boy, was that a miracle fix! Gorgeous detail was there with almost no loss in total bass energy. Indeed bass was now tighter. The "magic" that I heard in the Revel M16 was now imparted into KEF R3.
Playing with gain showed that there is a happy range for it. Too much attenuation did what you think intuitively: you lost bass. Too little and the magic would start to disappear.
Swapped out the R3 with Revel F35 and after a bit of gain adjustment, sweet sound was flowing like nobody's business!
My location for speaker testing is in one corner of my room. That is emphasizing bass modes. When Harman tests speakers, they place them in the center of the room and likely have worked to optimize the listening distance to reduce room modes. As it is, speakers with more bass get penalized. With my Revel Salon 2 tested the same way, the peak at 102 Hz was even higher requiring more gain reduction.
Note that the above is not an everyday issue as I use Dirac for room EQ for my system when it is normally being used. I had decided to test speakers without EQ and that came to bite me given the circumstances.
With this issue out of the way, I leaned on the Revel F35 to see how much clean power it can produce. Wow, this thing can take it and dish out. I could not believe the powerful bass and loudness I was getting out of a single speaker. There was no strain whatsoever making these speakers great for home theater as well as music listening.
Conclusions
While in the "budget" portion of Revel line, and too low priced to be considered as "high-end" by the audio industry, the Revel F35 objectively and subjectively produces stellar performance. A bit of low frequency EQ is all it took for it to sound good without any fiddling with location, toe-in, room treatment, etc, etc.
I am happy to recommend the Revel F35.
------------
As always, questions, comments, recommendations, etc. are welcome.
Have to drive out 130 miles tomorrow to pick up another speaker for review. Last I checked, gas is not free so please help me out by donating money using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Fit and finish is superb. You could easily pretend to your friends you paid multiples of its cost.
Disclaimer: Before I get into this review, and at the risk of stating the obvious, I have a million conflicts of interest here. I am a long time friend and professional colleague with a number of Harman employees (parent company of Revel). I have praised their design and research philosophy countless times. And our company, Madrona Digital is a Harman dealer (although we hardly sell any stereo gear). So read all the bias you want into the review but please don't go posting to complain. Just read the measurements if you are worried and if you don't trust that, just move along.
Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.
All measurements are reference to tweeter axis with the grill removed. Frequency resolution is 0.7 Hz (yes, less than 1 Hz) and plots are at 20 points/octave. Spatial 3-D resolution is 1 degree.
Over 1000 points around the speaker were measured (from 20 to 20 kHz) which resulted in well under 1% error in identification of the sound field across full frequency response of 20 to 20 kHz with the exception of lowest frequencies. I think this is due to multiple drivers creating a complex soundfield. This is the first "tower speaker" I have measured on the Klippel system so we will need more data to know what we are dealing with.
Final database of measurements and data is 1.2 Gigabytes in size.
Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:
As you would expect in any Revel speaker, the on-axis speaker is quite flat although not perfectly so. There are some glitches around and below 1 kHz that only showed up when I really pushed up the signal processing resolution. They don't show up in Harman anechoic measurements, nor do they show the saddle at 20 to 40 Hz. The latter I think is some kind of instrumentation error on my part per earlier explanation.
The SPL measurement is also speaker efficiency so we are talking about 90 dB which is above average in this day and age.
Predicted in-room response is very good given the nice directivity (off-axis being generally similar to on-axis especially horizontally):
I have added two key notes to the graph. The second one will become important later.
Impedance drops to near 3.5 Ohm so you need a beefy amplifier to drive this speaker:
Distortion as a percentage of output when driven with 10 volt input looks like this:
Putting aside the typical low frequency distortion, there is no other acoustic event of note.
Advanced Speaker Measurements
Early reflections which are the most audible in a typical room show that vertical reflections should be be absorbed or avoided:
Horizontal reflections are clean which you should take advantage of by NOT absorbing side walls:
Vertical reflections as noted above are not good:
So put a thick carpet on the floor. Frequency is high enough that 1 or 2 inch of absorption does the job.
You have the option of not pointing the speaker directly at you (blue for example of 20 degrees out):
Vertically based to stick with ear level which is there anyway given the height of the speaker:
Very nice horizontal spread:
Not so good vertically:
Speaker Listening Tests
Being simply the taller version of Revel M16 which I recently reviewed, I expected immediate gratification. Imagine my surprise when that did NOT happen! Detail was muddy and sound was not enjoyable reminding me of my test of KEF R3 which I just reviewed. How could this be?
We make fun of subjectivists often but hey, maybe we should listen to them sometimes. So I setup the speaker to play pink noise for 24 hours. Then I played my favorite tracks again. Wow. I could not believe my ears. All the micro-detail and detail materialized. Incredible!!!
Well, it would be incredible if the above was true but none of that is real. Where do you think we are? We don't believe in fantasties.
To borrow a line from the movie Martian, I decided to science the sh*t out of it. First I went back to KEF R3 to confirm that it had the same issue and it did. Two different speakers and the same problem? Both the R3 and F35 have more bass than M16 so how about a high pass filter? Dial one in quickly in Roon with a 6 dB decline starting at 100 Hz. Amazing. Some of the issues with R3 went away. Still not as good as the M16 but detail became better and sound fluidity improved.
Past experience with equalizing the room in low frequencies had taught me that removing bass resonances not only improves bass, but has a remarkable (good) effect on notes above that range. Resonances boost certain bass frequencies. In time domain that lengthens the amount of time it takes for those high energy notes to go away. And that steps on much lower level notes in higher frequencies.
So let's measure the room and see what we are working with (with KEF R3 on stand):
I have filtered this with 1/6 octave so there is not much clutter. Focusing below 200 Hz, we see our loudest and most offending peak is around 100 Hz. Let's dial in a single parametric filter by eye and see what does:
Beauty of Roon is that its filters can be switched on and off in a second. Boy, was that a miracle fix! Gorgeous detail was there with almost no loss in total bass energy. Indeed bass was now tighter. The "magic" that I heard in the Revel M16 was now imparted into KEF R3.
Playing with gain showed that there is a happy range for it. Too much attenuation did what you think intuitively: you lost bass. Too little and the magic would start to disappear.
Swapped out the R3 with Revel F35 and after a bit of gain adjustment, sweet sound was flowing like nobody's business!
My location for speaker testing is in one corner of my room. That is emphasizing bass modes. When Harman tests speakers, they place them in the center of the room and likely have worked to optimize the listening distance to reduce room modes. As it is, speakers with more bass get penalized. With my Revel Salon 2 tested the same way, the peak at 102 Hz was even higher requiring more gain reduction.
Note that the above is not an everyday issue as I use Dirac for room EQ for my system when it is normally being used. I had decided to test speakers without EQ and that came to bite me given the circumstances.
With this issue out of the way, I leaned on the Revel F35 to see how much clean power it can produce. Wow, this thing can take it and dish out. I could not believe the powerful bass and loudness I was getting out of a single speaker. There was no strain whatsoever making these speakers great for home theater as well as music listening.
Conclusions
While in the "budget" portion of Revel line, and too low priced to be considered as "high-end" by the audio industry, the Revel F35 objectively and subjectively produces stellar performance. A bit of low frequency EQ is all it took for it to sound good without any fiddling with location, toe-in, room treatment, etc, etc.
I am happy to recommend the Revel F35.
------------
As always, questions, comments, recommendations, etc. are welcome.
Have to drive out 130 miles tomorrow to pick up another speaker for review. Last I checked, gas is not free so please help me out by donating money using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
