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Standard for the measurement of a driver's FR
Standard for the measurement of a driver's FR
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Old 16th February 2020, 04:35 PM   #11
Scottmoose is offline Scottmoose  United Kingdom
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Originally Posted by Ant_222 View Post
I don't think a closed industry is a requirement. One purpose of standards is to facilitate mutual understanding between engineers by means of common points of reference.
No, nobody said it was a 'requirement', and yes, that is one of the main purposes of common standards. However, the fact is, it's not going to happen because they're selling product, not discussing engineering features.

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I do not deplore the absence of one standard to rule them all, but I should appreciate if manufacturers published the conditions under which they measure their products, perhaps in small type if PDF paper is expensive. It is a matter of mere reproducibility—a fundamental principle in experimental discipline.
You're speaking as though a commercial environment was an engineering laboratory.

Right: the truth. The majority of loudspeaker drive unit manufacturers have zero interest in doing so. It is not, as far as they are concerned, of much value to them under the current commercial conditions. It would take time and effort for little or no return, and most would rather their employees were engaged in other activities. There are exceptions, but not many. By and large, you would have to force them all, which is basically impossible.

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I see neither rhyme nor reason in normalising voltage, for drivers differ in power handling and sensitivity.
Yes, I know. It was a single example that is sometimes done for certain uses; nobody was advocating it for some blanket industry standard.

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One does not test with the same signal a sensitive paper driver intended for domestic use with a tube 3W SE amplifier and a tough rubber-suspension woofer designed for a movie theater sound system with a powerful transistor amplifier...Is that a problem? A decent Hi-Fi transistor amplifer should suffice as a signal source, because the inconsistency and inconstancy of driver parameters far outweighs any accuracy gain offered by dedicated equipment, does it not?
With a handful of exceptions, very possibly, but if you're going to invoke engineering consistency, you'd still have to standardise requirements for that as well. Good luck.

The fact is, you are certainly not the first to complain about this, and you won't be the last. But however much you, I and a small number of other enthusiasts might complain about it (and it's perfectly true: the current status quo is not at all satisfactory), the majority of manufacturers couldn't care less about what we think, because they still sell product, and only a very small proportion of their buyers are interested in said data. Commercial prioirities take precidence. If you can make it a commercial priority, then they'll start to be more interested.

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Agreed, but these discrepancies are of secondary magnitude and importance.
Want to bet? To give one example, there are current threads on this forum where drivers have published T/S data that is spectacularly inconsistent, i.e. if certain values are correct, the others in the same table cannot possibly be what is given, and the variation so enormous that any attempt to design using the published, inconsistent values goes to pieces. I wouldn't call that of 'secondary magnitude and importance' myself.
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Last edited by Scottmoose; 16th February 2020 at 04:43 PM.
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Old 16th February 2020, 05:27 PM   #12
OMNIFEX is offline OMNIFEX  Jamaica
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Originally Posted by Scottmoose View Post
Want to bet? To give one example, there are current threads on this forum where drivers have published T/S data that is spectacularly inconsistent, i.e. if certain values are correct, the others in the same table cannot possibly be what is given, and the variation so enormous that any attempt to design using the published, inconsistent values goes to pieces. I wouldn't call that of 'secondary magnitude and importance' myself.
The inconsistency of TS Parameters by certain brands have been around for decades. That is nothing new. Based on my measurements Eminence is the only brand that I would not make the effort to measure . This is due to owning a good amount of their loudspeakers. Eminence TS Parameters reflect their new driver fresh out of the box. Unfortunately, there are many that tend to turn up their nose to Eminence.

There is a difference between a loudspeaker manufacture that distributes their speakers primary to loudspeaker companies worldwide and, a loudspeaker manufacture that distributes their speakers solely to hobbyists where a large portion do not know nor care what the TS Parameters mean.
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Old 16th February 2020, 07:38 PM   #13
Ant_222 is offline Ant_222  Russian Federation
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Originally Posted by Scottmoose View Post
Want to bet? To give one example, there are current threads on this forum where drivers have published T/S data that is spectacularly inconsistent, i.e. if certain values are correct, the others in the same table cannot possibly be what is given, and the variation so enormous that any attempt to design using the published, inconsistent values goes to pieces. I wouldn't call that of 'secondary magnitude and importance' myself.
Not having had many new expensive foreign (non-Russian) drivers, I didn't know T/S were so unreliable all over the world. I can excuse, however, my old Soviet ones, many of which sound well anyway...

With the measurement conditions, one should be able, at least, to separate systematic error from random deviation.
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Old 16th February 2020, 08:14 PM   #14
Scottmoose is offline Scottmoose  United Kingdom
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One would hope so, but I fear we'll be in for quite a wait.
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Old 16th February 2020, 08:34 PM   #15
planet10 is offline planet10  Canada
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Standard for the measurement of a driver's FR
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Originally Posted by Ant_222 View Post
Another obscure matter is the signal source used to measure the T/S parameters: what output impedance, voltage, and current?
T/S are not single numbers, they are curves that are a function of drive, weather (temp, humidity & pressure), nature of the test jig, driver orientation.

The numbers you see are collapsed at some point from the curve. Pick a different point on the curve and you usually get different numbers.

At least with the driverís i have used from the better manufacturers, the factory numbers typically lead me to the best boxes.

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