Revel Performa3 F208 loudspeaker Measurements

Sidebar 3: Measurements

I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Revel Performa3 F208's frequency response in the farfield, and an Earthworks QTC-40 for the nearfield responses. The F208 is a large, bulky speaker, so it wasn't possible for me to raise it far enough above the floor to get good frequency resolution in the midrange. Bear this mind as you read on.

My estimate of the F208's voltage sensitivity, measured on the tweeter axis, was 88.9dB(B)/2.83V/m, which is within experimental error of the specified 88.5dB. The speaker's plots of impedance magnitude and electrical phase angle against frequency are shown in fig.1. The impedance ranges between 4 and 7 ohms for most of the audioband, though there are dips to 3.6 ohms at 100Hz and 3.2 or 3.7 ohms at 2.9kHz, depending on whether the HF control switch is set to its maximum or minimum, respectively. The phase angle is generally low, or high only when the impedance is also high, ameliorating its effect. However, the combination of 5 ohms and –50° at 25Hz means that the F208 will need to be driven by a good 4 ohm-rated amplifier. As Erick Lichte noted, the speaker worked better from his tube amplifier's 4 ohm than from its 8 ohm output.

714R208fig1.jpg

Fig.1 Revel Performa3 F208, electrical impedance (solid) and phase (dashed) with HF control set to its maximum (bottom traces) and minimum (top) (2 ohms/vertical div.).

The impedance traces are free from the small wrinkles in the midrange that would suggest the presence of cabinet resonances of various kinds. However, when I investigated the enclosure panels' vibrational behavior, I did find a fairly strong mode at 465Hz on the sidewalls level with the midrange drive-unit (fig.2). As EL didn't comment on any midrange congestion, I assume that this mode measures worse than it sounds, both because the frequency is high and because the affected area of the panel is small.

714R208fig2.jpg

Fig.2 Revel Performa3 F208, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of side panel level with midrange drive-unit (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

Fig.3 shows the individual responses of the port (red trace), the woofers (blue), and the midrange/tweeter section (green), scaled in the ratios of the square roots of their radiating areas. The woofer response is actually the sum of the outputs of the two woofers, whose minimum-motion notches are at slightly different frequencies: the top woofer at 30Hz, the bottom at 25.4Hz, the discrepancy perhaps due to manufacturing tolerances. Their combined output has a sharply defined notch at 27.3Hz, the frequency of the saddle in the impedance-magnitude trace, which indicates the tuning frequency of the port. The port's output peaks at this frequency, as expected, and cleanly rolls off above 40Hz, with no resonant modes evident in the midrange. The woofers cross over to the midrange drive-unit at around 260Hz, close to the specified 270Hz, with a steep filter slope. The apparent boost in the woofer's response is due to the nearfield measurement technique, and can also be seen in the overall response (fig.4), calculated from measurements taken with the LF control set to Flat rather than Boundary. But it is also apparent that the F208 is a full-range design, with useful output down to below 30Hz.

714R208fig3.jpg

Fig.3 Revel Performa3 F208, acoustic crossover on tweeter axis at 50", corrected for microphone response, with nearfield responses of midrange unit (green trace), woofer (blue), and port (red), respectively plotted below 355Hz, 1kHz, and 320Hz.

714R208fig4.jpg

Fig.4 Revel Performa3 F208, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with complex sum of nearfield responses plotted below 300Hz.

The F208's upper-frequency response is remarkably smooth and flat in both fig.3, taken on the tweeter axis, and fig.4, which was averaged across a 30° horizontal window centered on the same axis. There is a very slight lack of energy between 1 and 2kHz and a slight excess above 9kHz, but both of these errors will have very little effect on sound quality, if at all. The trace in fig.4 was taken with the HF control centered; set to its maximum and minimum positions, it raised or lowered the speaker's output above 3kHz by the specified 1dB.

The Revel's horizontal dispersion, normalized to the tweeter-axis response, is shown in fig.5. The use of a waveguide around the tweeter results in well-controlled off-axis behavior in the treble, which in a listening room of typical size will compensate for the slight top-octave boost seen in figs. 3 and 4. The smooth off-axis traces and even spacing of the contour lines in this graph correlate with the well-defined stereo imaging noted by EL. In the vertical plane (fig.6), the use of high-order crossover filters results in very little change in the speaker's balance over a wide range of listener heights—a good thing, given the tweeter's height from the ground of 43".

714R208fig5.jpg

Fig.5 Revel Performa3 F208, lateral-response family at 50", normalized to response on tweeter axis, from back to front: differences in response 90–5° off axis, reference response, differences in response 5–90° off axis.

714R208fig6.jpg

Fig.6 Revel Performa3 F208, vertical-response family at 50" without grille, normalized to response on tweeter axis, from back to front: differences in response 10–5° above axis, reference response, differences in response 5–15° below axis.

In the time domain, the F208's step response on the tweeter axis (fig.7) reveals that all four drive-units are connected in positive acoustic polarity, and that the decay of each driver's step is smoothly integrated with the start of the step of the driver next lower in frequency. This correlates with the excellent frequency-domain integration of their outputs seen in fig.4. The cumulative spectral-decay plot on the tweeter axis has limited midrange resolution due to the need to window out the reflections of the woofers' outputs from the too-close floor, but fig.8 still reveals a superbly clean decay in the treble.

714R208fig7.jpg

Fig.7 Revel Performa3 F208, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).

714R208fig8.jpg

Fig.8 Revel Performa3 F208, cumulative spectral-decay plot on tweeter axis at 50" (0.15ms risetime).

Summing up the Revel's measured performance is easy: In every way, this is textbook loudspeaker design. It's no wonder that Erick Lichte liked this speaker as much as he did.—John Atkinson

COMPANY INFO
Revel
Harman Luxury Audio Group
8500 Balboa Boulevard
Northridge, CA 91329
(888) 691-4171
ARTICLE CONTENTS

COMMENTS
Ajani's picture

I always wanted to read a Stereophile review comparing the second gen Performa models with the old ones. So this review really was a treat. It makes up for never officially reviewing the second gen, with the three-way comparison between the F30, F52 and the current F208.

Since this is your new reference, does that mean you'll be replacing your F30s? :)

Yossie Goldberg's picture

I’m considering purchasing the F208, my concern about the bass response in a 13sqm room, I am in the process of renovations and the speakers will be relocated into a room between 20-25sqm. Should I purchase the F206 instead?

ken mac's picture

What's the deal? Analogplanet.com is currently a parking lot for GoDaddy.

John Atkinson's picture
ken mac wrote:
What's the deal? Analogplanet.com is currently a parking lot for GoDaddy.

Due to an oversight, the domain registration wasn't renewed in a timely manner. AnalogPlanet.com is now back up again.

John Atkinson
Editor, Stereophile

bierfeldt's picture

I would like to see a review of the Performa3 M105s as it would highlight how special the whole line is. Additionally, those M105s are very attainable and provide a nice alternative to the B&W CM5s.

John Atkinson's picture
bierfeldt wrote:
I would like to see a review of the Performa3 M105s as it would highlight how special the whole line is.

Bob Reina reviews the M106 in our September issue.

John Atkinson
Editor, Stereophile

remlab's picture

Those look like SB Acoustics drive units. Is this a new thing for Revel? Or have they always outsourced? It seems to me that Harman would have a lot of good driver options within the company.

jmsent's picture

You've got a keen eye. Most of Harman's loudspeaker production is being outsourced these days. They design it, somebody else builds it.

Anon2's picture

When is Stereophile going to review the new B&W 685s2?

This product has been reviewed without delay by a peer publication in Europe, to much acclaim, and a couple of months after the product's introduction.

If I am right on my facts, the also much-acclaimed B&W 685 (series 1), an eminently popular speaker, was never tested by Stereophile.

I hope that Stereophile will test the B&W 685s2. It is the "most followed" new product on a peer website.

Also, I await a long-overdue testing of the Amphion Argon3. This product has been tested by a publication in North America. This is a somewhat expensive product. It would be interesting to know how Stereophile views the cost-to-performance ratio. Amphion, if you refer to their site, has 8 dealers in the US.

Finally, I would advocate for a full re-publication, on Stereophile's online edition, of the Dynaudio Focus 160. I know I can ask for a reprint edition. Given the attention the Focus 160 garners in the online world, Stereophile would serve its community well by chiming-in, again, with a full re-publication of its review.

Another, final, thought. I believe that Stereophile, again lagging its European peers, has yet to issue a review of the B&W PM1.

You do a great job. There are many products to review, and only 24 hours in a day. Still, these are four stand-out, stand-mounters that deserve a review, or re-publication for the online readers of Stereophile.

John Atkinson's picture
low2midhifi wrote:
I hope that Stereophile will test the B&W 685s2...Also, I await a long-overdue testing of the Amphion Argon3.

Thanks for the suggestions.

low2midhifi wrote:
I would advocate for a full re-publication, on Stereophile's online edition, of the Dynaudio Focus 160.

Sam Tellig's January 2012 review will be posted in our free on-line archives next week.

John Atkinson
Editor, Stereophile

JDDisantis's picture

I havent seen a focal review in a while. Will there be any in the future? like of the new aria series with flax cones or the refreshed chorus 705v entries?

John Atkinson's picture
JDDisantis wrote:
havent seen a focal review in a while. Will there be any in the future?

Bob Deutsch will be reviewing the Focal 936 loudspeaker in the October or November issue.

John Atkinson
Editor, Stereophile

badboy07's picture

It's really unfortunate what Harman has done to all of the old Madrigal Audio Labs brands but I suppose that's the "new global marketplace" excuse for sending manufacturing overseas while raising prices. Cannondale Bicycles did the same thing. They were the last of the American "mass market" brands that still manufactured on American soil, just as Harman with their luxury brands. I guess I'm just an old sentimental fool to pretend that the Average Joe can buy an American made product that is better than average.

DangeRuss's picture

As I wish Proceed still existed ....... It's bad enough that Harman abandoned the separates market.

badboy07's picture

And really, who is going to drive a $5000 pair of speakers with a 16lb AV receiver with a switch-mode power supply?

I used to be a Harman fanboy, but (and especially after killing Infinity) they sure make it difficult to respect their company.

otaku's picture

>> And really, who is going to drive a $5000 pair of speakers with a 16lb AV receiver with a switch-mode power supply?

Obviously the same people that would put that equipment rack and TV set between the speakers.

fin1bxn's picture

Having owned the F52's for over 4 years, driving them with a PASS X250.5 amp and have auditioned the F208, I can confidently say they are not in the same league. The F52 crush the F208 in all areas of performance.

Strat's picture

You own the F52's and are obviously stuck with them. That could be the only reason for that type of comment. My dealer in Chicago had the 52's, I passed and I'm glad I did after hearing the F208's.

Good review as usual Erick.

starfirebird's picture

"...because the F208 is only 11.8" wide and the entire rear panel curves around in a parabola, its appearance is far less imposing than the boxy, Volvo-like F30."

Um, Erick, have you acutally taken a look at any Volvos recently? It's been quite a while since they were really boxy (not that there's anything wrong with that), and these days are decidedly anti-boxy. (And for those who think this means they don't look like Volvos anymore, it should also be noted that classic Volvos of the 60's weren't boxy either -- that's a rep they earned only in the 70's and 80's.)

ValentinR's picture

wish you had done some in room measurments
Revel is very good @ in room balance an the F208 measurments should show that

Synthetic's picture

Agreed, that's very disappointing.

Calliope's picture

Very interesting review! You inserted a lot of details and your explanation is very clear and well-written. This loudspeaker reminds me of some products by Sonus faber (this is the official website: http://www.sonusfaber.com/en-US/home-page/) ...am I the only one?

trmoore2's picture

These speakers are just as fabulous as the review. However I wanted to point out one audio myth: The quote from the review: "The F208s eventually took about 500 hours of play before achieving their ultimate sound."

I called Harman about "speaker burn in" or different "coloration" after they've been played awhile. Harman/Revel said "THIS IS AN AUDIO MYTH WITH NO TRUTH." I'm assuming propagated by speaker salespeople; the subtext being "these babies will just get better over time!" I can attest after 2 years, the F208's sound the same to me, but I do enjoy them more everyday.

Bixby's picture

In the review Mr. Lichte notes his room is rather small. I'm curious to know the approximate size, as well as how far away he was sitting from the speakers. Thank you!

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