Saturday 19 December 2020

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 ;-).


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

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!


  1. Thanks Αρχιμαγο, I'm still using my Audioengine A2+. I'm now EQing parametrically, according to your measured frequency responce. I'll use the filter you created in the convolution option in my JRiver. I guess with the filter on, I won't EQ, right?
    Thanks again, greetings from Greece!

    1. Correct my friend.

      Although I don't have an AudioEngine A2+, if say I create a FIR filter like above, you'd be putting that in JRiver/Roon/foobar (with plugin)/etc. and turning off your parametric EQ...

      Of course, there's nothing stopping you from still applying some extra EQ to taste, plus there will be differences between speakers as well...

    2. BTW: Just uploaded a filter for the AudioEngine A2. I added some boost to the low frequencies (but not too extreme), took out that large bass hump, enhanced the midrange, and toned down the treble a little...

      Give it a try in JRiver! Watch out for distortion if you push the volume up too much as the bass accentuation will work the port. I don't have the AudioEngine A2 anymore so alas can't test myself...

    3. Alright, Thanks!
      I click the link to download your Audioengine filter, but it says the folder is empty. Could you upload it once again? Thanks in advance.Much appreciated!!!

    4. Fixed the AudioEngine A2 link... Enjoy...

  2. Dear "Mago", I'm an Italian 60th Old Hi-fi user and I line your job cause you Talk of Audiophilia with the "Common Sense" and without any commercial intest. Congrats.!!!
    BTW about Common Sense I really appreciate yours posts about MQA..
    A Common people feeling immedialy feel to' anyone that a Hard Manipulation of existing files with losses in IN and decompressione and filtering in OUT is as far ad possibile ti the concept of Hight FIDELITY .!!! .and also to' the concept of Master Quality..!!
    But despite this MQA is growin up more and more.
    Also indipendent Blogger like Darko says that MQA sounds Better.!? and forced by Tidal spread, even all Big and Little Chinese Manufactures are obligatory inserting MQA in new DAC Streamers releases..:-(
    This is the Power of MM, not Moving & Marketing .! :-(
    What we can do to fight against this Manipulation.
    For my side I've bought a Cheap Chinese Streamer Arylic S50 Pro that don't 've any MQA SW inside but Top Manufactures like Link or others can promuove Products named as "MQA FREE" or they 'll stopped for "Comparative Advertising"..? (I'm afraid so.)
    Merry Christmas "Mago" and January 6th don't forget to bring your(Audiophile) gifts to little Jesus ..
    Truth, Justice, Goodness..
    Have a nice 2021..

  3. Replies
    1. Hey there Lilloball17,
      Hope you're have a good Christmastime in Italy!

      Thanks for the note... Yeah, MQA. What can one say but that it's a sad reminder of the role that the audiophile press plays as the advertising arm of an Industry with many participants having a weak relationship with "truths" and "facts". Rather as you say, the "Power of MM" results in so-called journalists that are happy to repeat company claims without truly bothering to understand what is being sold to consumers - Darko, Atkinson, JVS, Harley, Fremer, Quint, Scoggins, etc. in this group. Thankfully not all who write in the audiophile world are of the same opinion.

      Given that audiophilia is a niche hobby of obsessive and overall I think more educated participants, I think it would be very cool if as a group, "rational audiophile" continue to take a stand and let MQA know simply that "Audiophiles aren't interested in compromised and partially lossy digital audio". They are free to advertise their claims to the world, but exclude audiophiles from this madness.

      To me, it's an opportunity for "audiophiles" to be counter-culture. If MQA is supposed to be "good", broadcasted to the masses over Tidal, it's actually natural for audiophiles to take a pass recognizing that this isn't "pure", "highest fidelity", nor an uncompromised "perfectionist audio" playback system worthy of the audiophile ideal.

      MQA/Stuart were IMO stupid to have pushed this on the audiophile press as if these guys had the respect and power to "pull a fast one" over the folks who cared the most about quality.

      Not just audiophiles of course, likewise, I hope the pro audio people can continue to voice some strong opinions when they're asked to sign on to the BS.

      Hmmm... Not sure what "little Jesus" has to do with January 6th? Orthodox Christmas is on January 7th. Isn't Jan 6 when the US Congress validates the election results? But then again you're Italian and I'm Canadian so I hope we're OK :-).

      Yes. "Truth, Justice, Goodness" - may it be so. Merry Christmas and Happy 2021!

    2. I completely agree with you "Mago" , except for role Exchange
      Rational audiophiles, but also simple Music Lover like me that stay at a much lower level, know and make Right Musical Culture healthy ..with common sense.
      Are those new "Marketing Prophets" who, taking advantage of lack of basic Music Culture in new generations (usimg Steaming Services), operate Contro(musical)culture, selling a damage for a miracle.
      And young peoples are satisfied with a fast post-produced listeming, according to their taste and conclude that ... it's a truly miracle, and they pay money over Money for this.!

      But ... if I told anyone that I would take Leonardo's paimting Mona Lisa from Louvre, and with a Software I fall back on itself, I remove some colors and nuances and then , with another specific software, I reopen it, even more than the original painting, and I add colors and shades also taking into account the various museums in which it will be exhibited, thus Realizing what Leonardo really idealized when he painted ... they would immediately shut me up in a psychiatric health stucyure 'cause simply doesn't make any sense.!!

      But unfortunately, as we say in Italy, .. In the blinds country an one-eye man becomes King..!!!

      Regarding what can be done practically, and right that everyone takes his responsibility in being truthful, unfortunately being in "this MM world" I believe that the only effective method would be to oppose "Business to Business.
      All Honest Producers who have no interest in selling "Fied Air" should joint forces with each others and produce simple advertising and information supports that reach everyone and not only Musical Elites, 'cause this Will be a Mass Movememt, explaining what damage is MQA and creating easy-to-remember slogans that summarize these concepts.
      I had thought of MQA FREE similar to the anti-GMO one or. "MQA? No Thanks" or.. I don't know "IN MUSIC LESS IS MORE" ...

      No one, except Majors, Jay-Z and Meridian would have any interest to comletely surrender yourself to MQA, paying for every movement in the supply chain.
      And certainly Honest Journalists should contribute their part.

      Otherwise id everything 'll be' delegated to individual opinions, I believe that MQA will inevitably become (and in part is yet) the 'Standard Streaming format for the next few years of all Quality Audio Sistems.
      And then ...MQA + .. MQA-CD...MQA VIDEO SURROUND .. where we 'll arrive ..?

      About us, here in Italy this year (with Covid-19) was very hard both from health economic and social point of view.
      We hope that 2021 will bring new air..(For me it is already good that we no longer have Trump in the White House.)

      January 6 th..? ... for us Catholicos (which means Universals...opens like free formats) is Jesus Epiphanic day (not to be confused with Ephipanic Audio) amd "Magis" like you, bring to the little Jesus 3 symbolic gifts ..Gold, Frankincense and Myrrh.

      Of course I know that Orthodox Calendar is different and I hope that in the future all Christians will've a "Unique, Free Format", also because alls chosemd dates, from "Fidelity" point of view are wrong..only the result of conventions and choices of opportunity. (like MQA)

      I greet you with the words of a song by your countrywoman Celin Dion, taken from "Thesr are Special Times" which has been our family's Christmas soundtrack for decades.
      "Oh God Bless Us Everyone.."

      Buon Natale "Mago".
      Maurizio Cerpelloni

    3. Ahhh, thank you Maurizio, I get the reference to January 6th and the "Mago". Nice to know and I shall bring what I can to the special occasion along with at least the other 2 Magi. :-)

      Good example with the Mona Lisa. This would indeed be what is happening if any studio were to be silly enough to delete the original "master" recording whether it be 24-bit/96, 192, DXD, etc. and somehow think that MQA could provide the same level of resolution as the original for archiving!

      I like the idea of a formal "movement" against MQA from music lovers and audiophiles alike. Indeed a simple slogan like "Free the music - NO MQA." could raise a few eyebrows and make the public take note of the many different ways that this "format" has been designed to impose excess costs, add complexity, and ultimately taking choice away from the consumer unnecessarily.

      Yeah, personally, I have no interest in giving any money to the co-owners of Tidal: Jay-Z, Beyonce, Nicki Minaj, Alicia Keys, Chris Martin, Jack White, Kanye West, Lil Wayne, Madonna, Usher, etc. unless it's for some worthwhile music.

      Not sure if MQA will be the "standard" in the years ahead. Hope not of course and I think the negative sentiment against it is strong. I suspect anyone who knows anything about MQA by now already knows that it's at best controversial among audiophiles. In so many ways, consumers (and in general tax payers) get screwed by corporations/governments all the time so nothing would be surprising anymore. I'm just glad I have a lifetime of music already in my library.

      Thank you for sharing the Celine Dion song. I will make sure to have a listen to that this holiday season!

      Merry Christmas to you Maurizio and the family.

    4. "Free the music - NO MQA."
      This 'll be my Signature in alls future posts about Music here and in other places..!!!

      Also simple dongle Manufacturers are "infected" by MQA ...😭
      (look at mail that I've adresses at you outlook mail inbox).

      Unfortunately, I am sure that if no one Producers and Opinion Makers "Raise the Voices", it will be so ..

      Free the music 🤑 - NO MQA 🗽🎸


    5. Great Maurizio. I'll make sure to add that to my signatures on forums as well :-).

  4. You forgot to include switches as an important part of the hi-fi equipment:

    On a more serious note, Archimago, thank you very much for all your hard work writing this blog! Almost every Monday when I go here, reading something here makes my day objectively better :) Merry Christmas, and let's hope for a better 2021!

    1. Unbelievable Freddie,
      Sure, take a classic name like "English Electric" and associating it with snake oil.

      Absolutely, let's look forward to better times in 2021 in all kinds of ways!

  5. I'm new to this blog but very glad I found it. Very helpful. And a welcome change from the marketing biased reviews that are so common. Thank You. I will be back often.

    1. Thanks Unknown,
      Wishing you a wonderful holiday season...

  6. Awesome!!!!! Thanks for sharing. keep going!!!!
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    in your budget.

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