Re: Optimum room dimensions.
My research shows that the optimum ratio of room dimensions depends on the size (volume) and shape of a given room. So there is simply NOT one ratio that is always optimum.
My conclusions come from studying Oscar Bonello's work from 3 decades ago. Briefly, he showed how the frequency and strength, distribution and statistics of room frequency modes form a basis for catagorizing room dimension ratios.
My article on this subject appeared around 1999 in Speaker Builder magazine (I'm not at home to specify exact date).
John F. Sehring
As a live acoustic music and accuracy git myself, I would not argue with your priorities.
However, in my opinion you've confused the behaviour of some of the groups. There are in my opinion several major groups of purchasers - e.g.:
i) Those who are deaf to the blandishment of snake-oil salesmen, who trust only their own ears, and are wise enough to use a wide range of listening material when selecting systems.
ii) Those who belong to the first group, but also believe accuracy helps make things sound better, and that measurements are a means to this end.
iii) Those who think only the ears count, but happily use highly-distorted starting material to make their judgements.
iv) Those who think they only accept the evidence of their ears but are influenced by snake-oil salesmen; and
v) Those who will accept any received "wisdom" without making personal checks.
I have no argument with members of the first two groups - albeit the effects of sound level, and human suggestibility (or overcompensation for the latter) mean that it is extremely difficult to be a member of the second (unless you have loads of friends with appropriate systems who will loan them for a week at a time).
The "distorted material" group is likely to be disappointed when they get the system home; and the other groups will generally overspend on snake oil.
Accuracy measurements do not support high-cost cabling. Both measurements and blind listening tests suggest that only resistance and inductance are important. I probably go further than most, as I use standard "twin and earth" mains cable for speaker connections. Conductor area and number of paralleled cables depend on distance.
While all of you possible sound engineers hark away at ear canal resonance, amp slew rate, mathematical dimensions of listening room and such esoteric funda, for the average listener who is a million mile away from such facts, what he likes when he hears is what matters. How in the world would one know how a royal philharmonic would sound when buying a CD. All that matters for one is how he likes when it plays on the device. So I would rather side with Audiofools saying accuracy matters but not at the expense of good sound which is the subjective part. Ironically people are willing to trade the latter for the former, go figure.
I don't know- you can have music played over $100,000 speakers with gold cables Vs a $1000 speaker with plain copper cables but one would be a fool to argue that the former is guaranteed to sound better.
Very interesting and informative discussion. As some have pointed out, and I believe most agree, is that much of the problem is with the source material.
I'm a retired engineer that's seen a lot of change over time and expect to see much more.
With sufficient processing power, and as much historical information we can dig up at our disposal, we should be able to recreate a model of the original performance. We could identify instruments, including the human voice, their locations and also some dynamics of recording environment.
With a rich descriptive language we should be able to transcribe the performances with any and all perceptible nuances. From there we could regenerate the performance.
"... but the frequency response drooped quite significantly above about 6Khz using lamp cord. "
Long ago I heard a theory that the lower the resistance of the speaker cable, the better the low amplifier output impedance would dampen speaker cone resonances. Have you done any experimentation to compare 18 gauge lampcord with 12 gauge (household electrical) wire?
BTW, I cannot comment much on hearing vs measurement, I have "iron ears" caused by too loud a volume with headphones in my mis-guided youth. Those of you with kids, caution them to keep their music at a low volume.
P.S. For what it is worth...Langford Smith's team were able to detect 0.75%. My recollection is that other workers were able to demonstrate about 0.3% under the most "favourable" conditions; however, this could be a mis-remembering as I don't have easy access to check chapter and verse.
Thank you for elaborating on my point (the relevance is what can be ignored). Shame it reads as if it is intended to be a contradiction (especially as many authors treat inability to hear harmonic distortion as an aspect of masking).
As a side-issue: the physical ear is a multi-resonant system. Nevertheless, we perceive difference tones similar to those produced by second-order intermodulation. So we can live with moderate levels of 2nd-order intermods. But 3rd order can be excruciating. Have you seen a decent explanation?
My favorite "snake oil" is the harmonic distortion in vacuum tube amplifiers: Whenever you have a tube amp you also have an impedance matching **iron core** transformer, which is also needed to keep plate voltage away from the output terminals. Because of hysteresis, the transformer I/O curve is NOT linear: Instead, the output is the convolution of the input current and the hysteresis curve (envelope).
Knowledge of EM in general and hysteresis in particlar is also how I separate out the men from the boys (& other pretenders) in the EE profession…
Editor, The Hearing Blog
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