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Temperature Control In Speaker Measurements

thewas_

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Wombat

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#22
Normally, the burden for "enlightenment" rests with the one making the accusations. You have not produced a single measurement of a single speaker showing the output variation vs. temperature when measured at the distance the Klippel measures them. Show us one of those so we can see the magnitude of the variations at the temperatures in question (is it 10 db or 0.1 db max deviation?) and a constructive conversation might begin.
The burden of proof rests with the original claimant. Get that right.

'Prove me wrong' is BS.

Prove your primary claim is correct, is how it works. Then prove other associated claims are, likewise, correct. These claims are subject to considered challenge and must reasonably withstand them to have validity.
 
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Wombat

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#23
As with "break-in," the mechanics of drivers can change but once you put them in the box, those effects become negligible. Alan can say all he wants. As long as he is not posting measurements, his comments are without value.

People listen to speakers at all kinds of temps. In hotel rooms at shows temps vary hugely as does humidity level. Never heard of one exhibitor complaining about the temperature impacting speaker performance.

Regardless, it is not much of an issue. The temp is around 55 to 57 degrees F or about 13 degrees C. Yes that is "cold" to us that live on the west coast. :) The garage is insulated and rarely goes up above 65 degrees F during summer. If a speaker operates worse in such moderate temps, then its measurements better damn it this way....
Alan Harbeth has credibility with many years in overall loudspeaker design compared to a hobby guy with a recently purchased off-the-shelf measuring device. Humility please.
 

Jon AA

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#26
The burden of proof rests with the original claimant.
YOU are the "claimant." You are the one casting aspersions on the data over a variable when you have no idea if that variable has any meaningful impact on the results.

I "claim" that the phase of the moon causes large variation in speaker performance. I "claim" measurements conducted on any day that is not a full moon are complete bunk! I guess it's up to Amir to prove me wrong now.....

Amir could spend all his time "debunking claims" and get no more speakers measured if that standard was followed.

Show us some data--any data--that indicates this is something worth worrying about and a meaningful conversation will ensue. What you've done so far is nothing more than throwing crap at the wall to see if it will stick.
 

Jon AA

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#27
Alan Harbeth has credibility with many years in overall loudspeaker design compared to a hobby guy with a recently purchased off-the-shelf measuring device. Humility please.
Sorry, but when somebody says 20 to 30 degrees C represents a 50% temperature change, he's lost the interest of anybody with a scientific background in the subject he's discussing.
 

Wombat

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#28
YOU are the "claimant." You are the one casting aspersions on the data over a variable when you have no idea if that variable has any meaningful impact on the results.

I "claim" that the phase of the moon causes large variation in speaker performance. I "claim" measurements conducted on any day that is not a full moon are complete bunk! I guess it's up to Amir to prove me wrong now.....

Amir could spend all his time "debunking claims" and get no more speakers measured if that standard was followed.

Show us some data--any data--that indicates this is something worth worrying about and a meaningful conversation will ensue. What you've done so far is nothing more than throwing crap at the wall to see if it will stick.
What is your level of qualification/experience in Science/Engineering and related testing?

Simple question. Simple answer please.

The ASR test results must withstand fair scrutiny regardless of throughput.
 
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Frank Dernie

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#30
From my work on polymers, not speaker surrounds but the same type of material, I would only expect temperature changes in the surround to affect the bass and iirc the measurements here don't give a high importance to this aspect, rather assuming good bass extension.
Voicecoil heating and cooling is so localised that the ambient room temperature effect will be minuscule.
 

Wombat

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#31
Sorry, but when somebody says 20 to 30 degrees C represents a 50% temperature change, he's lost the interest of anybody with a scientific background in the subject he's discussing.
Well it does on the Celcius scale, referenced to 0 degrees C, actually. Which temperature scale and point reference are you not stating?
 

RayDunzl

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#34
Absolute zero on Celsius –273.15 degrees.

So, 20C = 293.15 units of temperature
and 30C = 303.15 units of temperature

The difference being 10/303.15 = 3.29%
or 10/293.15 = 3.41%

Just for argument's sake.

(that may not be exactly right, but I find it closer than 50%, and I never think "Gee, it's X% hotter today than yesterday!")
 
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RayDunzl

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#35
Ah-ha.

I have independently discovered the Kelvin scale, by referencing C to absolute zero. Never before have I had to worry about Kelvin, here in Nu-Perfect America.

20C = 293.15 K
30C = 303.15K

@Wombat
"Your arithmetic is correct but your result is arbitrary. When expressing a temperature change as a percentage, one must use a temperature scale whose zero point is the temperature of absolute zero, and then use that selected scale consistently. The Kelvin scale is such a temperature scale. All other temperature systems, like Fahrenheit and Celsius, have arbitrary "zero points," and calculations of percent temperature change using those scales will give arbitrary results." - https://mathnotations.blogspot.com/2008/02/temperature-changed-from-5-to-5-degrees.html
 

Jon AA

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#36
Yup, pretty much every material known to man has mechanical properties that will change with temperature. You use formulas, charts, curves, etc on a daily basis when designing mechanical devices. In none of those charts does a property go to infinity or zero at 0 C....except, of course, the viscosity of water. ;)
 

PierreV

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#37
Yup, pretty much every material known to man has mechanical properties that will change with temperature. You use formulas, charts, curves, etc on a daily basis when designing mechanical devices. In none of those charts does a property go to infinity or zero at 0 C....except, of course, the viscosity of water. ;)
I know this was a tongue-in-cheek comment, but still :)

1582027757942.png
 

Wombat

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#38
Degree in Mechanical Engineering. 20 years at Boeing (ending as a Senior Engineer/Lead Stress Analyst). You?
…… and you didn't know about the burden of proof?

Me? Degree in Electrical Engineering. Career in power station operation, power transmission and distribution systems operation and control, Statewide power system load forecasting, generation scheduling and energy interchange co-ordination between States. HV system maintenance, electrical process heating design, corporate Safety Engineer, corporate Policies and Procedures Engineer(Electrical), ISO9000 series Senior Lead Auditor. Now well and truly retired.

Thank you for your reply.
 

restorer-john

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#39
From my work on polymers, not speaker surrounds but the same type of material, I would only expect temperature changes in the surround to affect the bass and iirc the measurements here don't give a high importance to this aspect, rather assuming good bass extension.
I have two identical Yamaha woofers and they have the same impedance sweeps when at room temperature.

Just put one in the fridge (see pic). Let's see what happens in half an hour or so, I'll compare a room temperature one with a cold one. :)

1582066910019.jpeg


Who else in the world has a woofer in their fridge, huh?
 

RayDunzl

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#40
Who else in the world has a woofer in their fridge, huh?

Not me, but you must admit the barrier to enter that exclusive club is not a very high hurdle.
 
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