My column last month, “The Biggest Lie in Audio,” sparked lots of commentary, but it also raised questions that are tough to answer. While most of the people commenting on the article here and elsewhere found it to be a welcome relief from what some have called the “faith based” approach of many audio publications, some weren’t so complimentary. A few derided science-oriented, “objectivist” writers as “narrow-minded” because they criticize audio products that don’t conform to generally accepted performance standards. Some insist that there’s no such thing as “accuracy” (they always put that word in quotes) in music reproduction, so audio writers have no basis on which to criticize outlier products.

These statements raise an important question that everyone involved in audio -- from enthusiasts to reviewers to engineers to scientists -- must consider: can accuracy in music reproduction exist?

Sound Reproduction

I’ve seen criticism of the notion of accuracy in audio reproduction from a wide range of people, including everyone from esteemed scientists to reviewers who don’t know Ohm’s Law from Boston Legal. As famed audio researcher Floyd Toole explains in his book Sound Reproduction, the lack of standards in the recording and consumer audio industries creates a “circle of confusion” that makes it nearly impossible for a listener to know how a recording is supposed to sound.

The circle of confusion starts in the recording studio, where recordings are made using microphones, EQ, and effects that are evaluated using monitor speakers, which are evaluated by using . . . recordings.

The circle continues in the homes of enthusiasts and reviewers, who evaluate audio components using recordings made in studios that the listener probably hasn’t visited, using equipment whose identity is usually unknown, and with which the listener is probably unfamiliar. And of course, the acoustical environment of the listener’s home is likely to be considerably different from that of the studio where the mixing and EQ decisions for the recording in question were made.

(On a side note, I once consulted on the design and voicing of recording monitors. When I suggested making the frequency response flat, the product manager replied, with some hesitation, “I understand that . . . but we want our customers’ mixes to sound awesome.”)

Although Toole doesn’t mention it in this section of the book, headphones create yet another circle of confusion, because the usual goal of headphone design is to get them to sound as close as possible to . . . good speakers in a good room. And of course, those speakers were determined to be “good” through the use of . . . recordings.


Adding more confusion is the focus of most audio research on listener preference rather than on accuracy. That’s an understandable approach, because manufacturers want to design products people will like. But as I found when I compared live sound to recorded sound during my review of AudioQuest’s idiosyncratic NightHawk headphones, the sound that most listeners prefer isn’t necessarily the closest reproduction of a live performance.

So there’s plenty of uncertainty about what constitutes “accurate” music reproduction. The problem is that this confusion can be exploited.

Before we consider that, though, it’s important to consider that while accuracy is an uncertain concept in audio, there is clearly such a thing as inaccuracy. For example, say you took a ten-band (one octave) equalizer and boosted the 20-to-40Hz band by 12dB, cut the 40-to-80Hz band by 12dB, and continued this boost/cut pattern right up the audioband. No matter what recording you play, or what musical instruments or test tones you use as a reference, this would sound unnatural, and would not be what the artist or the recording engineer wanted you to hear. We can say with certainty that this sound reproduction is inaccurate.


Beyond extreme examples such as this one, our certainty diminishes, and the opportunities to be led astray in our choices of audio gear multiply.

Let’s say you have headphones with a midrange that’s down by 10dB relative to the bass and treble -- a phenomenon easy to find in headphones and speakers, including some high-end models. This response is going to make the music sound different from what the artist and recording engineer heard in the studio, and it’s going to make recordings of voices and acoustic instruments sound unnatural.

But the designer can excuse this flaw simply by saying, “We don’t know for sure what’s ‘accurate’ [always in quotes!], and this response sounds good to me.” A subjective reviewer, listening on their own without input from others, might go along with this assessment, interpreting the dip as a “liquid midrange” or whatever.

I don’t think criticizing this approach is “narrow-minded.” This idea that “We don’t really know what’s ‘accurate,’ so whatever an audio product designer wants to do is OK because that’s their personal vision” reminds me of the way my friend and fellow reviewer Dennis Burger once characterized the statements of would-be medical experts on the Internet: “Science isn’t perfect, so homeopathy works.”

We’ll probably never achieve complete accuracy in audio reproduction. Speakers and headphones can’t mimic the widely different radiating characteristics of real instruments, nor can headphones or a listening room precisely duplicate the acoustics of the original studio or venue.

We can, however, say that some audio products provide more accurate reproduction than others do. A headphone amp with flat frequency response and 1-ohm output impedance will more faithfully replicate what the artist and recording engineer heard in the studio than will a headphone amp with a 300-ohm output impedance and -3dB rolloff at 20Hz and 20kHz. Headphones that conform reasonably closely to the Harman curve will get you closer to the artists’ and engineers’ intent than will, say, the original Beats headphones, which had colossally boosted bass.

If a designer wants to deviate from accepted norms of audio performance, I think the potential buyer for that designer’s product deserves more explanation than “I think it sounds better this way.” To that designer, I say, “Show me your credentials.” And by that, I mean not just years of experience in audio product design, but years of experience with music. I want some assurance that the designer knows what real -- as well as electrical and electronic -- instruments sound like.

How much time have they spent in recording studios, or recording live music events? Do they own and regularly perform on any instruments? How much cognizance do they have of the decisions musicians and engineers make when performing and recording, and how the equipment the musicians and engineers use affects the sound?

Then I’d like to know how much time they’ve spent listening to products that do conform to industry norms. And would it really be too much to ask for them to provide a hearing test taken in the last five years?

Or to put it more simply: if you want us to respect your taste and your “vision,” give us reasons why we should. Because while accuracy remains an elusive concept in audio, most listeners can tell when you’re getting close. And some aren’t afraid to call you out when you’re way off.

. . . Brent Butterworth
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  • This commment is unpublished.
    Dush · 4 years ago
    With headphones the FR determines totally how the headphone sounds. There's no messy room to deal with.

    With speakers it's a minefield with the room. Using an opensource tool, Impulcifer, you can create your own Head Releated Impulse responses (HRIR) from loud speakers in a room measured with binural mics in your own ears. Effectively you "virtualize" your speakers/room.

    In doing that for a year now I've realised that what a frequency response graph looks like, or even time domain information have little to do with how a room actually sounds. You can make an ideal measurement in one room. Be completely convinced that it sounds identical to your real speakers, and therefore sounds "good". You take that HRIR into another room and it sounds like crap. The brain is expecting something different.

    I've taken a HRIR in my main theater, where the sound is great to my ears and on REW's measurements. I then sit at my laptop with the same sound and it sounds like ass - I can hear way too much reverb. But when I sit down in the same seat I made the impulse response I hear none of the reverb. Why? We listen with our eyes. Our brain processes that out as it's expecting it.

    So the circle of confusion continues - even if we get speaker characteristics right - the room certainly isn't. And rooms can measure very similar and sound completely different. Just by moving seat. If albums were mixed with headphones in mind - none of this would be an issue - you'd just need to nail FR.

    Sound is messy, I'm getting to the point where I feel reference is a silly concept. Your brain is always adapting, always filtering a lot out.
    • This commment is unpublished.
      Brent Butterworth · 3 years ago
      I will definitely check that out! I do my music mixing on headphones, despite that I'm told "The first thing they teach you in recording school is never mix on headphones." It's because I found some headphones (Status Audio CB-1) I can use where my mixes translate well to things like computer speakers and the little speakers built into smartphones, and of course to most other headphones. Yet the mixes sound good on my Revels, too. I don't know if it has to do with eliminating the room, or just the FR of the headphones, or something else, but it's working.
      • This commment is unpublished.
        Dush · 3 years ago
        I think it's most likely that the headphones let you make proper mixing decisions. When those other speakers are used for playback it sounds good to you and others because your brain takes care of it.

        For example, you really have to train hard to hear low Q dips in FR or an in room flat frequency response across the range in loud speakers. The brain fills those gaps in.

        If you mix, really take a look at Impulcifer (https://github.com/jaakkopasanen/Impulcifer). It's like Waves NX tracking, but with a custom HRTF. Waves alone is pretty good for cross feed/head tracking if stereo imagining is something you want to prioritize.
  • This commment is unpublished.
    todd · 4 years ago
    Sound united is claiming 1 elderly Japanese soud master is tuning one brand to be clean and dynamic while another sound master tunes their sister brand to be warm and musical. Are they really trying to have their products add to the sound as opposed to trying to have, for example their amps reproduce the source material as accurately as possible ?
    • This commment is unpublished.
      Brent Butterworth · 4 years ago
      So this is Denon and Marantz?
      • This commment is unpublished.
        Mauro · 4 years ago
        I have seen pretty different measured performances on Audioscienceview. Denon x3600 for example is one of the most accurate measured AVRs, especially the preout that can reach confidently 2 volts with low distortion. Marantz sr6014 has a good amplification but has a pretty fancy slow roll off at high frequencies..

        But I wonder How does this translates to perceived sound? I would be curious to read about a double blind test that sorts it out (mm)

        I remember once I did a test and among many different amplifiers (Marantz, Nuprime, Exposure) just one stood out: Atoll IN SE 200.. who knows if this would measure good or bad. I would be curious to know..
        • This commment is unpublished.
          Brent Butterworth · 4 years ago
          This whole concept of "tuning" electronics is questionable. I have asked several times what engineers do when they supposedly "tune" electronics. Is it, like, different frequencies, slopes and knees in the high-pass filter on the gain stage feedback loop? TMK, that and maybe a capacitor-coupled input are the only sections of a standard, three-stage AB amp where there's intentional filtering that could be adjusted, but usually that's 50kHz or higher. I have never received an answer. And where are the documented blind tests that confirm the efficacy of these tweaks? But the idea of an master engineer with golden ears and decades of experience is certainly appealing from a marketing standpoint.
          • This commment is unpublished.
            Mauro · 4 years ago
            Out of curiosity, how did you pick your current AVR and stereo receiver?

            Have you manage to find a compromise between Room EQ and pure stereo amplification? In my experience: Significant better bass vs slightly better midrange and high frequency refinement..
            • This commment is unpublished.
              Brent Butterworth · 4 years ago
              It was a long and complex process. First, it's important to note that I don't review AV receivers, only speakers. So a few years ago, I needed a receiver with Atmos, and my friend Dennis Burger said, "I have a Sony that'll do everything you need, and I'm not using it. I'll check with the Sony guy to see if he's OK with me sending it to you." And the Sony guy said OK, so here we are.

              I have never used the room EQ on it, and I never used the Audyssey on the Denon I had previously. I'm too scared I might accidentally switch the room EQ on while I'm reviewing a speaker, which would of course totally skew the review.

              On my stereo rig, I bought a Parasound Halo P5 because it had a subwoofer crossover, and I'm using Outlaw M2200 amps because I already had one I was using for speaker measurement (chosen in part because of its robust short-circuit protection - a good thing to have when measuring speakers or reviewing!), so I bought a second one.
              • This commment is unpublished.
                Mauro · 4 years ago
                Thanks for sharing. Who knows that my Revel F206 might benefit as well from two Outlaw monoblocks..

                I value a lot Dennis AVR reviews. I am using room EQ with an Audyssey app to define the maximum frequency on my Marantz AVR based on his recommendation. High five for Dennis! (h5)
      • This commment is unpublished.
        Todd · 4 years ago
        • This commment is unpublished.
          Brent Butterworth · 4 years ago
          See below. I see all this as more marketing than engineering. I did an article years ago about Sony's "master receiver tuner," Takashi Kanai, in Japan. I'm not sure how much difference that kind of tuning makes, but it makes it more appealing to me to know that it has the seal of approval from that guy. https://www.soundandvision.com/content/mad-scientist-sony-audio
          • This commment is unpublished.
            Todd · 4 years ago
            Thanks Brent, I wanted to thank you for your responses and thank you for measuring in a time when most publication's don't bother.
            I also appreciate when you enlist the opinions of other trained listeners and that in some of your work you put competing products from different brands right up against each other in a shootout, blind testing, fashion. This used to be done all the time by publication's when I was growing up. Now, it seems you're the only one that's doing this and I find that type of article along with measurements to be most helpful when making a purchase.

            As to Denon and Marantz and there elderly Japanese sound Masters, I don't know how much science there is in there tuning but I found it interesting to learn from their YouTube posting that Marantz has more parts and they're claiming only 47% of the parts are shared between Denon and Marantz despite identical specs. My guess would be any audible difference between such receivers or integrated amps is most likely attributed to differences inroom correction software which is showing up on more and more products.
            Still, I know these are fighting words in high-end audio and there is a YouTube post from Denon Marantz that claims they can hear the difference between their own products.

            I do find the information interesting though, because at least we have some rationale for why the Marantz cost more than the Denon but sometimes more parts or more expensive parts may not necessarily result in an audible difference. I think Integra still claims that their parts are hand selected I wonder how this is even possible when scaling a product at a factory.

            Thanks again for all that you do. I will check out the article on the Sony Sound Master.
  • This commment is unpublished.
    gzost · 4 years ago
    Thank you for another well-argued article!

    The "circle of confusion" is a problem, but I think its severity is often overstated.

    The discussions about accuracy on the playback side really only concern the speakers + room and headphones + head - I do not see any problem with DACs, amps and interconnects.

    I listen to a lot of classical music. I am not much of a concert goer, but I, like I think a majority of people interested in music and audio reproduction, have heard solo instruments and ensembles across an overall large number of different acoustic situations. My brain has constructed models for what a piano, a cello or a full symphonic orchestra sounds like, independent of a particular venue.

    Listening to a single recording of classical music comes with too many variables to say much about a pair of headphones. The venue may have had strange acoustics or the recording may not be a fair representation of what happened in front of the microphones.

    However, if I listen to a large number of recordings and the sound of the vast majority tracks well with the mental models I have of the instruments involved, then I think it is a fair assumption that the headphones reproduce things well. The likelihood of all recordings being off in the same manner becomes smaller with more recordings, styles recorded, and especially with recordings across multiple decades using different technologies.

    In my experience, a headphone reproducing acoustic instruments well tracks really well with the measurements that are done of them, especially regarding the frequency response. Harman curve, diffuse field, the curve that Sonarworks uses - to me they are all valid options and present as realistic, and the closer a headphone gets to them the better (also: EQ helps, a lot!). A few more dB bass or presence boost matter less to me than having a smooth frequency response with a sane pinna gain. On the other hand, having a "wobbly" frequency response always sounds off overall.

    (A wobbly frequency response can, of course, sound better with some recordings. Personally, I see no sense in going hunting across my headphone collection for the most "synergistic" reproduction of individual tracks, and I consider it insane that for people who own only one or a couple of headphones their gear should influence what music they can really enjoy!)

  • This commment is unpublished.
    Mauro · 4 years ago
    Long life to Brent Butterworth and Dennis Burger that embraced science and not homeopathy!! (nod)
    Nice article !

    I liked the interview on the Steve Guttenberg channel with John Atkinson partially covering this topic, if anyone might be interested..

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