MEASUREMENTS: Tannoy REVEAL 501a powered monitors

Today, let's have a look and listen to the speakers you see above.

These Tannoy REVEAL 501a, though discontinued now and replaced with the newer Tannoy REVEAL 502 released in 2014, have been well-regarded over the years in home studio use (check out some user reviews here and on Amazon). They were first released back around 2010 and there's a good Sound On Sound write-up from mid-2011. These were budget priced at <US$500/pair on release (typically sold as individual speakers) although over the years, could be found for a relative steal down at US$200/pair.

These are biamped powered speakers - 40W mid/bass and 20W tweeter, unknown without opening them if these are Class A/B or D amps. There's a 1" soft dome tweeter, 5" mid/woofer, flared front port, and the box is MDF with curved front baffle. Dimensions are 11.9" x 7.3" x 9.4"; relatively small speakers. Each box is individually powered unlike the AudioEngine A2 or Edifier S2000 Mk III previously discussed where there is a cable tethering the speakers together, weighing about 6kg and quite solid in the hand.

Here's what the rear looks like:

The speaker accepts both XLR and unbalanced 1/4" inputs. There's a high-frequency trim to adjust +/-1.5dB at 2.3kHz which is the specified crossover point. Unless specified otherwise, I will measure with the trim at 0dB. Standard IEC power connector, voltage selection and power switch round off the bits you see on the back.

I. Measurements

"Your midrange or your life!" - grabbing the mid-woofer nearfield response... Remember that although I've applied baffle compensation, nearfield measurements do tend to accentuate the bass response.

About a year ago, I posted some basic measurements of these while visiting my friend linnrd's place. Let's go into more detail on their performance with this post.

Here's the "qSpin" CTA-2034A-inspired result, based on a blend of windowed and nearfield measurements:

Two anomalies automatically jump out in the frequency response. First there's a mid-range dip down into 1.7kHz. Second we see a rise in levels into the upper treble. Although there is a relative treble prominence, bass response does reach down to 50Hz.

While the directivity is quite flat from 1.25-8kHz, notice that the DI dips (dispersion widens) into 9kHz and then the tweeter quite rapidly "beams" into 20kHz (narrowing dispersion). We can see this pattern in the polar maps:

As expected, there's asymmetry as a result of the vertically arranged drivers (and port). Best to listen about +/-30° horizontally, stay less than 15° above, and no more than 30° below the tweeter axis.

Looking into the time domain, we can have a peek at the step response and the spectral decay:

Tweeter and mid/woofer are both in positive acoustic polarity on the step response. The cumulative spectral decay plot (3ms with at 25dB dynamic range) looks good with very little resonance suggesting a well-dampened box.

Using 200ms dynamic bursts at increasing amplitude, the linearity looks excellent from 70dB to 100dB SPL at 1m with at most around 0.5dB deviance from expected at the extremes of that range (calibrated to 85dB SPL as 0 point):

Let's have a peek at distortion characteristics:

Certainly not the cleanest THD or IMD I've measured. While IMD was able to maintain around 1% or better into 80dB SPL, it climbs quickly by 90dB SPL at 1m. Remembers that as powered speakers, these results will also be dependent on the quality of the built-in amplifiers employed by Tannoy.

How well does a pair of REVEAL 501a's match?

"Right" or "Left" speakers were selected arbitrarily of course. These Tannoy speakers were sold as individual units and the 2 I tested have quite different serial numbers (8062XX and 8254XX).  Despite that, on the frequency response, we see at most 2dB difference mainly around 1.7kHz and 15kHz regions. Ideally, I would like to see <1dB difference between the speakers but this is not bad.

The cumulative spectral decay plots look well matched, suggesting consistent quality control and a box without troublesome resonances.

II. Subjective

Here they are in my listening room beside my usual Paradigm Signature S8 v.3 speakers. Notice the small blue LED power indicator up front. As usual, I listened to these speakers before running the measurements discussed above in order for my subjective opinions to not be affect by the numbers and graphs. For the record, the listening chain was:

Server computer running Roon --> Raspberry Pi 4 streamer (RoPieee) --> RME ADI-2 Pro FS R Black Edition DAC --> Emotiva XSP-1 preamp --> Tannoy REVEAL 501a

All analogue interconnect wiring was inexpensive XLR (combination of 6' Cable Matters XLR and surprisingly good quality 10' SRADIO XLR). Generic 6' IEC power cables for the Tannoys.

I turned the Tannoy volume up to 100% on both speakers while using the pre-amp to adjust playback loudness. I noticed a hiss from the drivers, certainly not terrible and inaudible from the listening position but a bit more than my main Paradigm speakers paired with either the Emotiva XPA-1L or Hypex nCore NC252MP amps.

These powered speakers were loud enough to fill the room as I would ever need. Needless to say, these are small 5" woofers so don't expect prodigious bass. One would of course want to pair these with subs if you need to hear the lowest octave well. Having said this, one of the first tracks I played was "Into The Blue" (Lydia Ainsworth on Darling of the Afterglow) and was actually rather impressed that I could hear some of the lower bass content.

Soundstage was good and I appreciated the ability for these little speakers to render a good sense of depth in the live Jason Mraz album Beautiful Mess: Live on Earth and 10,000 Maniacs' MTV Unplugged.

Indeed, they can sound harsh on the high end. Pop recordings like Alison Moyet's "Is This Love?" (from Raindancing) and other early '80s stuff like Johnny Hates Jazz's Turn Back The Clock simply sounded too "lean" (more than they normally do!). Female vocals (Roon selected Selena's "Dreaming of You" one evening) could be rather fatiguing after awhile.

Although this is the "subjective" section of the review, I think it's an appropriate time to bring up the fact that there is a high-frequency "trim" switch on the rear of the speaker which will help reduce the overly-bright tendency:

As you can see, the trim setting affects frequencies above 2kHz.

Even with -1.5dB, it doesn't completely take away the tendency for harshness though. With the -1.5dB applied, a modern "vocal pop" album like the recent Josh Groban's Harmony sounded quite good with nice "front-and-center" vocal imaging and overall good tonal balance. Unfortunately, Groban's recordings have never been great for dynamic range (average DR7 value for Harmony - there's no real hi-res here). With electronic tunes like James Blake's "Can't Believe The Way We Flow" (from Assume Form), the Tannoys did a great job with reproducing the synthetic surround, ethereal effects.

In the sound room, small-scale classical quartets (like Melos Quartett Stuttgart's Schubert: The String Quartets) sounded great with good dynamics, excellent clarity and precise soundstage. As usual I find with small speakers of this type, more complex pieces like say Stephen Layton/Britten Sinfonia's Handel Messiah really demanded the "power" of the main sound system with full-sized speakers and sub for the full "presence" and magnificence to be rendered in the room.

III. Summary

The Tannoy REVEAL 501a is a well-made powered budget monitor speaker targeted mainly for "home-studio" use as discussed in the Sound On Sound 2011 review. Nice to see both XLR and unbalanced inputs. There's enough power to fill my soundroom to normal listening levels (average between 70-90dB SPL). Despite quite different serial numbers, the 2 speakers compared here seemed to be a good match.

I would say that the S-O-S review was spot-on describing the sound from these speakers. Indeed, the bass did not sound overly hyped and went down quite low for 5" woofers. Although it's not a strong bass, it does give us some extension down to 50Hz or so before dropping off quickly. One should watch out for the rising high frequencies above 2kHz. No need to fear using EQ of course.

It's interesting to see the S-O-S review bringing up and comparing these with the "classic" Yamaha NS10 speakers used in many studios back in the day which also tended to be bright and "forward". Bob Hodas has an old article discussing the use of tissue paper to tame the treble. While I have not heard the NS10, I guess at least I have a sense of what the harshness might have sounded like. Remember, as much as audiophiles might bring up the latest and greatest audio hardware with potentially huge price tags not to mention all kinds of fancy cables and stuff, don't forget that many of the studio recordings including modern online content we enjoy were produced using speakers like these or the Yamaha NS10. Here's an interesting recent comparison of the REVEAL 502 vs. other common "home studio" monitors.

A couple of other limitations I saw/heard with these speakers were the higher background hiss with the volume turned up and the THD/IMD also a little elevated (especially harmonic distortion ~400Hz). While the 501a has been discontinued, hopefully some of these limitations have been addressed with the current REVEAL 502 model.

To close, let's look at one last graph. Here's how the Tannoy 501a (0dB HF trim) compares with some of the other speakers I've run through the "qSpin" procedure over the last few months:

This is the "listening window" frequency response for each small speaker. While looking at one curve may be simplistic, I think at least to some extent, the reader can appreciate how this could help with understanding the sound from these speakers beyond just subjective words. Unless the speaker has high distortion or dynamic range limitations, frequency response remains the most important determinant of the experienced quality.

Although I don't have all the speakers side-by-side to compare, I can say that the curves above provide a reasonable demonstration of what I heard among the different devices. If you've ever heard the AudioEngine A2 for example, you'll appreciate the lack of bass response on account of its small 2.75" woofer. The most expensive of the speakers is the KEF LS50 and you can see that it has the smoothest frequency response as well although it doesn't quite go down as deep as the Edifier S2000 Mk III or the Tannoy discussed today.

One interesting comparison is between the Fluance XL8S (measured here) vs. the Tannoy REVEAL 501a. These two speakers are almost on opposite extremes when it comes to high frequency response! While the Tannoy accentuates the content >2kHz, the Fluance does the opposite and instead leads to a more recessed treble, in essence comparatively accentuating the mid-range and bass. Neither would be considered "neutral", and for accurate studio production work, the LS50 (or the latest KEF LS50 Meta) with sub would clearly be superior.

Based on the experience with these speakers on my computer workstation, I would say my favourite on that graph is the Edifier S2000 Mk III with its grille on. While it was not without its limitations, it sounded smooth, had good bass extension and was easy to listen to for hours without fatigue.

As audiophiles/music lovers, I think it's obvious looking at the comparison graph above just how much difference the choice of speaker makes! These variations in frequency response would be on the orders of magnitude difference compared to digital front ends, reasonable DACs, and high fidelity amplifiers. The other major source of sonic difference is the room setup and if you're an analogue listener, the inaccuracies of turntable technology could be considerable.

We are of course free to choose whichever type of sound we prefer. Each person will have psychological preferences (the mind) as well as individual "hardware" differences (the ears). I can imagine if one has mild high-frequency hearing limitations, the REVEAL's treble accentuation might actually be preferable. There is no absolute "right" or "wrong" to subjective preferences, just variations on "different" even if objectively we can point out the devices with more accurate reproduction qualities...

Thanks again to my friend linnrd for letting me borrow these speakers for the last couple months ;-).

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Bonus:

Using my qSpin data, I created this stereo 64-bit/96kHz 64k-tap FIR filter:

Tannoy REVEAL 501a (0dB HF Trim) - Correction FIR.zip

Sounds pretty good using the Roon convolution engine, taking away the excess "sizzle" in the treble. The difference is not subtle. This is based on the 0dB trim setting so you're still free to use the +1.5dB switch to tip the frequency response up or -1.5dB to taper the treble >2kHz further lower.

Anyhow, if you guys find this works/useful, I'm happy to provide similar correction filters for future measurements...

Hope you're all having a good December so far!