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Some thoughts on ASR and the reviews

I’ve briefly taken a look at some online reviews for budget Tekton speakers from ASR and Youtube. Both are based on Klippel quasi-anechoic measurements to achieve "in-room" simulations.

As an amateur speaker designer, and lover of graphs and data I have some thoughts. I mostly hope this helps the entire A’gon community get a little more perspective into how a speaker builder would think about the data.

Of course, I’ve only skimmed the data I’ve seen, I’m no expert, and have no eyes or ears on actual Tekton speakers. Please take this as purely an academic exercise based on limited and incomplete knowledge.

1. Speaker pricing.

One ASR review spends an amazing amount of time and effort analyzing the ~$800 US Tekton M-Lore. That price compares very favorably with a full Seas A26 kit from Madisound, around $1,700. I mean, not sure these inexpensive speakers deserve quite the nit-picking done here.

2. Measuring mid-woofers is hard.

The standard practice for analyzing speakers is called "quasi-anechoic." That is, we pretend to do so in a room free of reflections or boundaries. You do this with very close measurements (within 1/2") of the components, blended together. There are a couple of ways this can be incomplete though.

a - Midwoofers measure much worse this way than in a truly anechoic room. The 7" Scanspeak Revelators are good examples of this. The close mic response is deceptively bad but the 1m in-room measurements smooth out a lot of problems. If you took the close-mic measurements (as seen in the spec sheet) as correct you’d make the wrong crossover.

b - Baffle step - As popularized and researched by the late, great Jeff Bagby, the effects of the baffle on the output need to be included in any whole speaker/room simulation, which of course also means the speaker should have this built in when it is not a near-wall speaker. I don’t know enough about the Klippel simulation, but if this is not included you’ll get a bass-lite expereinced compared to real life. The effects of baffle compensation is to have more bass, but an overall lower sensitivity rating.

For both of those reasons, an actual in-room measurement is critical to assessing actual speaker behavior. We may not all have the same room, but this is a great way to see the actual mid-woofer response as well as the effects of any baffle step compensation.

Looking at the quasi anechoic measurements done by ASR and Erin it _seems_ that these speakers are not compensated, which may be OK if close-wall placement is expected.

In either event, you really want to see the actual in-room response, not just the simulated response before passing judgement. If I had to critique based strictly on the measurements and simulations, I’d 100% wonder if a better design wouldn’t be to trade sensitivity for more bass, and the in-room response would tell me that.

3. Crossover point and dispersion

One of the most important choices a speaker designer has is picking the -3 or -6 dB point for the high and low pass filters. A lot of things have to be balanced and traded off, including cost of crossover parts.

Both of the reviews, above, seem to imply a crossover point that is too high for a smooth transition from the woofer to the tweeters. No speaker can avoid rolling off the treble as you go off-axis, but the best at this do so very evenly. This gives the best off-axis performance and offers up great imaging and wide sweet spots. You’d think this was a budget speaker problem, but it is not. Look at reviews for B&W’s D series speakers, and many Focal models as examples of expensive, well received speakers that don’t excel at this.

Speakers which DO typically excel here include Revel and Magico. This is by no means a story that you should buy Revel because B&W sucks, at all. Buy what you like. I’m just pointing out that this limited dispersion problem is not at all unique to Tekton. And in fact many other Tekton speakers don’t suffer this particular set of challenges.

In the case of the M-Lore, the tweeter has really amazingly good dynamic range. If I was the designer I’d definitely want to ask if I could lower the crossover 1 kHz, which would give up a little power handling but improve the off-axis response.  One big reason not to is crossover costs.  I may have to add more parts to flatten the tweeter response well enough to extend it's useful range.  In other words, a higher crossover point may hide tweeter deficiencies.  Again, Tekton is NOT alone if they did this calculus.

I’ve probably made a lot of omissions here, but I hope this helps readers think about speaker performance and costs in a more complete manner. The listening tests always matter more than the measurements, so finding reviewers with trustworthy ears is really more important than taste-makers who let the tools, which may not be properly used, judge the experience.

erik_squires
mahgister's avatar
mahgister
13,181 posts
 

Now read this by a top physicist in fluid mechanic who is also a top audio designer of world wide fame who also design his own amplifier and speakers:

 

 

An innovative approach to suppress the distortion of electronics
Dr. Hans R.E. van Maanen (Temporal Coherence)

«Every amplifier, no matter how well made, distorts. Don’t be fooled: the distortion-free amplifier still needs to be invented. The distortion, introduced by electronics, is even at low levels, annoying, which is why all designers strive for an as low as possible distortion level of their brain child. And in order to be able to compare results, the distortion is measured and is expressed in a number, usually a percentage. Sadly enough, in reality this so-called “distortion figure” shows to be indicative at best, but it certainly is not an absolute measure for how we experience the quality of the sound reproduction. This can easily be
demonstrated by a couple of simple examples from daily practice: a loudspeaker commonly distorts at least 0.5%, which is significantly more than the 0.01% of a good semiconductor amplifier. Yet, the misery, introduced by the amplifier, is clearly audible using such loudspeakers. Although valve (tube) amplifiers have distortion figures which are significantly higher than those of semiconductor amplifiers, still a lot of music lovers prefer the sound of valve amplifiers. Also, there is no guarantee that a semiconductor amplifier with 0.001% distortion “sounds” better than one with 0.01% distortion. Unfortunately, we will not be able to dig deeper into the backgrounds of this paradox, but it is important to remember that a
distortion figure is barely informative on the experienced, sonic, quality of an amplifier.»

https://www.temporalcoherence.nl/images/docs/Distortion.pdf

Only this short quote by a scientist as well known as Toole in acoustics destruct all Amir pretense about tube amplifier being bad and S.S. being good ...

Now about the way high frequency signals way over 20KHZ affect sound perception of human :

«In-
audible high-frequency sounds affect brain activity: hypersonic effect.
J Neurophysiol 83: 3548 –3558, 2000. Although it is generally ac-
cepted that humans cannot perceive sounds in the frequency range
above 20 kHz, the question of whether the existence of such “inau-
dible” high-frequency components may affect the acoustic perception
of audible sounds remains unanswered. In this study, we used nonin-
vasive physiological measurements of brain responses to provide
evidence that sounds containing high-frequency components (HFCs)
above the audible range significantly affect the brain activity of
listeners. »

https://linearaudio.net/sites/linearaudio.net/files/high%20freq%20inpact%20on%20brain.pdf

 

I think Amir need to study acoustics more and digital signals less...

 

 

kevn's avatar
kevn
162 posts
 

Thanks @nonoise 

@erik_squires - I’m sorry for not acknowledging your original post earlier - it was a terrific read for me and pointed out clear and understandable facts regarding the measurement of speakers that go beyond a single viewpoint or method, and engage relationships, acoustic and electromagnetic. Thanks for your insights.

 

in friendship - kevin

mahgister's avatar
mahgister
13,181 posts
 

other very important consideration about the 20KHZ limits of audibility :

«One of the major problems is that it is fundamentally impossible to determine the
requirements for sound reproduction systems by sound reproduction systems: when something is “inaudible” is this because of the limitation of human hearing or because of the limitation of the sound reproduction system (including the microphone(s), sound recording and storage system)? By designing a sound reproduction system, you have to start somewhere and I have been told numerous times that the 20 kHz limit is based on the Fletcher�Munson curves. Apart from that, although I have deep respect for what people achieved 60 years ago, I seriously doubt that the equipment they had available in those days is superior to human hearing and any conclusions drawn from their work should be critically
examined with our current knowledge, which, however, still leads to conflicting results. So far, I have never heard a sound reproduction system which comes even close to the live performance of a symphony orchestra. So there is still a lot of work to be done and we need deeper understanding of the workings of human hearing. In that perspective, I find the
historic background of the 20 kHz limit less interesting; more interesting is the question whether we need an extended frequency response in order to bridge the gap with the symphony orchestra as this 20 kHz number has penetrated the whole audio business. Just look at the specifications of the different components from microphones to recording equipment to tweeters»

 

Hans Van Maanen Linear audio vol.5

 
 

 

 

mahgister's avatar
mahgister
13,181 posts
 

Now to go further read this:

 

«The discussion on the perceived quality of audio systems often lacks
objective criteria. This is partly due to the subjective experience of the
ill-defined property "quality", covering many aspects, partly to the lack
of understanding of all the properties that influence the perceived
quality. The latter is not synonymous with the technical quality of a
system to begin with.
Disregarding non-linear distortions, the frequency response between 20 Hz
and 20 kHz of a system is very often taken as a major parameter determining
the quality of a sound reproduction system. The basic idea behind this is
the Fourier analysis of sounds, in which any sound wave, no matter how
complicated, can be decomposed into an infinite series of sine and cosine
waves of different frequencies, starting at zero and "ending" at infinity.
The, never mentioned, assumption is that the frequency components above the
hearing limit, usually taken at 20 kHz, do not influence the perceived
sound in any way.
Although this seems a reasonable assumption at first, it is not as
straightforward as one would think. Two aspects play an important role: the
first is that Fourier analysis only holds for linear systems and if there
is one transducer which is non-linear, it is the human ear. In non-linear

systems frequencies not present in the original signal can be generated
and/or other frequencies can acquire more power than in the original sig-
nal. This can easily be demonstrated using a 3 kHz sine wave with 5 periods
on and 5 periods off. Although Fourier analysis tells that 300 Hz is only a
weak component in this signal, it is the strongest one hears. As 300 Hz
corresponds to the envelope of the signal it is not surprising using the
non-linear properties of our ears. It can be concluded that frequencies
above the hearing limit can indeed generate signals that are below the
hearing limit which could thus influence the perceived sound and the
quality experienced.»
 
 
 

 

 

mahgister's avatar
mahgister
13,181 posts
 

Then Amir is a seller of his limited set of tools , his stance on tube amplifier made no sense in acoustics, and his interpretation of the results of his Fourier tools are acoustically meaningless because human hearing dont work as Amir want it to do to sell his marketing measuring  site ...

Van Maanen is a scientist known worldwide in audio .

Amir is not...By far.... Even with 2 million visitors...

Science is not made in a marketing site of audio reviews...

 

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