Measurement Bias

Measurement bias is the idea that if you know the measurements of something that information will already bias your perceptions of it’s performance. For instance, knowing the g-force at which car A might slip vs. car B could affect your perception. B, having a higher g-force rating should be a "better" car but if you did not know this you might rate A as better. It may be more fun to drive.

I’ve seen this happen in a review in (I believe) TAS. The review was for a DAC I purchased. The reviewer noted it as "noisy." I read this after I had purchased and been listening to the DAC for a while. I was more than a little shocked, I could hear no noise whatsoever from the DAC. I pulled out an oscilloscope and sure enough, there was unexpected ultrasonic noise on the outputs. I eventually did sell the DAC, but not because it was at all noisy, but because new DACs handled Redbook (44.1kHz/16 bit) tracks so much better. Nowhere in the review did the reviewer mention they had measured it, and they certainly did not point out the deficiencies in Redbook playback, but the reviewer absolutely presented this DAC as noisy but otherwise OK.

So, my point is, that making assessments on the experience that comes from a measurement in audio is tricky business, and if the reviewer is aware of the measurements ahead of time it will absolutely bias them into hearing things which they’d otherwise not, and leave them blind to other real world challenges.

If you want to put together desirability with measurements you need to look at the work Floyd Toole or Bose have done and others in this area and you wont’ find it in a frequency response chart. Of course, Bose’s research is proprietary, but absolutely no one one earth has spent more money on assessing value vs. measurements and manufacturing dollar than Bose.

PS - Please don't argue the quality of Bose speakers here.  I'm not arguing for or against them.  I'm arguing that the research done in tying together desirability and engineering direction is outstanding.  That is all.


Not I or anyone I know have purchased any piece of equipment based on any kind of measurement.  I'll have to start asking people and see what I find out.  We build components and we do measure the parts quality to match certain parts as we believe and hear differences when we do this, but not all of the parts.

Happy Listening.


One of the reasons this endeavor is so entertaining is that there are no standards for what a stereo system should sound like. It would be impossible to make them. The same speaker in three different rooms is three different sounds. Three different types of speaker in the same room are three different sounds. It is up to every single one of us to tailor our systems to sound the way we want in the room we have available within financial constraints. I personally believe principles are more important than measurements. Some measurements are more important than others, but given the range of issues related to speaker performance in situ, specifications and test measurements reside in the background.

I have said on multiple occasions, what someone says any piece of equipment sounds like means nothing to me because I have no way to interpret this. I only care what I think something, usually a loudspeaker sounds like in my room. When it comes to loudspeakers the specs are virtually meaningless, but the design speaks volumes. In many instances the specs are misleading. 

The important measurements to make are those you can make in your own listening room in regards to amplitude, group delay and dispersion. If you can't hear distortion any measurement is of no significance. If you can't hear noise any noise level is of no significance. 



Both are great, lets scientifically measure them and listen to them. You will end up picking a component that works best for you for any number of reasons. Your bias will be there regardless, for the numbers or for the brand, or for the price, or for the room you auditioned your component in, or for a reviewer, or for word of mouth, or for what you believe sounded better because of an A/B sound comparison which would mostly likely be unreliable (depending on you memory and/or chosen A/B components)... and the list goes on...

These discussions on either side are beyond ridiculous.

One of the reasons this endeavor is so entertaining is that there are no standards for what a stereo system should sound like.


Well, I think THX did a pretty good job for home theater systems in auditoriums which included acoustic requirements and in specifying speaker requirements for homes as well.  We just kind of ignore it all for stereo.

stereophile does it right.  reviewers don’t know the measurements until their review is complete.  keeps them on their toes.  if measurements show a clear flaw that should be relatively easy to hear, and they didn’t hear it, their credibility is shot.  hearing is inherently more biased than measurements, but agree measurements can bias us.  but so can the amt of $ spent.  just on those three factors (there are many others) I would rate them ears, $, measurement in descending order of potential for bias.  the key is what steps we take for each to mitigate the potential for bias.