keyne said:SE,
i don't know if this was meant to be a joke but...
you could probably use any piece of ME-quality silicon as a rather sloppy strain gauge...
but not if it's packaged.
Hehehe. Wasn't meant as a joke at all. It was quite a long time ago though. I believe it was mentioned by someone on the old The Audiophile Network BBS back in the late 80s. Wish I could recall more details but that's the best I can do after more than 10 years. Sorry.
se
So far as quoting from a text book!
When i got out of school i thought that what i had learned and studied was the exact truth,well years of hands on experience has proven that wrong in many cases.The only way to properly test anything is to try to re-create the conditions that the test object will be subjected to and provide extensive measuring of the response from the test.However even that dosent always prove to provide for the actual in use conditions.There always is some un-accounted for force that will affect the total performance (look at the Tacoma Narrows bridge).Thats why a good ME goes for at least 100% overdesign.
As stated before my background is strictly ME as the only EE courses i took were required so i always bow down to the more experienced EE types.
ron
When i got out of school i thought that what i had learned and studied was the exact truth,well years of hands on experience has proven that wrong in many cases.The only way to properly test anything is to try to re-create the conditions that the test object will be subjected to and provide extensive measuring of the response from the test.However even that dosent always prove to provide for the actual in use conditions.There always is some un-accounted for force that will affect the total performance (look at the Tacoma Narrows bridge).Thats why a good ME goes for at least 100% overdesign.
As stated before my background is strictly ME as the only EE courses i took were required so i always bow down to the more experienced EE types.
ron
Doovieman said:
you will be disappointed, if history is of any indication.
This is a unique forum in that we have a lot of golden ears who can hear all sorts of "effects", and they will assure you that you will hear the same effects as well, as long as you have been exposed correctly to high-end equipment. For example, we have people who can hear resistor sound, or 9mm signal path vs. 10mm signal path, or mica insulators, or copper heatsinks, etc. Tho. no one has said so far that they can hear heatsinks of different chemistry,
.You have a noble cause but I am afraid that psudo science will essentially dominate the discussion here.
Re: What about Piezoresistive Sensors
I am doing due diligence on a defense electronics company that specilizes in ruggedization of single board computers and comms/io boards for military applications (tanks, fighters and missiles). The company don't develop the electronics themselves but borrower COTS (commercial-off-the-shelf) designs and ruggedize them.
The biggest efforts are in securing contacts, joints, and devices themselves. No one has concerned, so far, about microphonics.
so if microphonies aren't a concern in a tank fire control computer, I doubt it should be a concerned for home audio applications.
Unless you have a pair of golden ears that outmeasures the most sensitive electronics available today.
sounder said:
I am doing due diligence on a defense electronics company that specilizes in ruggedization of single board computers and comms/io boards for military applications (tanks, fighters and missiles). The company don't develop the electronics themselves but borrower COTS (commercial-off-the-shelf) designs and ruggedize them.
The biggest efforts are in securing contacts, joints, and devices themselves. No one has concerned, so far, about microphonics.
so if microphonies aren't a concern in a tank fire control computer, I doubt it should be a concerned for home audio applications.
Unless you have a pair of golden ears that outmeasures the most sensitive electronics available today.
Re: Re: What about Piezoresistive Sensors
Konnichiwa,
Hmmm. You make leaps of logic that astound me. Just because a binary system which works on two basic logical states and has most likely binary in/out or if analogue maybe with 8 Bit precision does not show microphonic effects nothing can.... Congratulations....
As someone who has worked in process control electronics (yes, even some process controls for military stuff for the old East Block) I would have to note that the dynamic ranges and bandwidth of such system are usually quite coarse and Missile or tank firing system are no exception.
A modern, high performance audio system has around 100 to 126db dynamic range (the 100db should be pretty standard, the 126db are the very bleeding edges of what is doable) and a bandwidth of something close to DC to usually 40-100KHz.
If we rewrite this in a different notation, the analogue resolution of a common audio system is around 10ppm (part per million) with the best approaching 0.5ppm or expressed in scientific notation 10^5 to 20^6 dynamic range!!!! These are levels that in medical perparations are considered "homeopathic".
And if we express the bandwidth in decades and take a modern wideband audio system (10Hz - 100KHz flat - not terribly difficult) we could say that we cover four decades in frequency bandwidth.
And yes, I will contend that under specific conditions the human ear/brain system can react to phenomenae in these region as well.
So, I would think few people will try to argue that even in chips microphonic effects can be present that exceed 10ppm at common music listening levels and they certain exceedd this level in ANY sort of capacitor.
Hence, I will contend easily that what makes no difference to the accuracy of killing other humans may very well make material differences to the process of providing people with musical enjoyment. As usual, it is much easier to kill and destroy than to something positive (1st law of thermodynamic).
Sayonara
Konnichiwa,
millwood said:
Hmmm. You make leaps of logic that astound me. Just because a binary system which works on two basic logical states and has most likely binary in/out or if analogue maybe with 8 Bit precision does not show microphonic effects nothing can.... Congratulations....
As someone who has worked in process control electronics (yes, even some process controls for military stuff for the old East Block) I would have to note that the dynamic ranges and bandwidth of such system are usually quite coarse and Missile or tank firing system are no exception.
A modern, high performance audio system has around 100 to 126db dynamic range (the 100db should be pretty standard, the 126db are the very bleeding edges of what is doable) and a bandwidth of something close to DC to usually 40-100KHz.
If we rewrite this in a different notation, the analogue resolution of a common audio system is around 10ppm (part per million) with the best approaching 0.5ppm or expressed in scientific notation 10^5 to 20^6 dynamic range!!!! These are levels that in medical perparations are considered "homeopathic".
And if we express the bandwidth in decades and take a modern wideband audio system (10Hz - 100KHz flat - not terribly difficult) we could say that we cover four decades in frequency bandwidth.
And yes, I will contend that under specific conditions the human ear/brain system can react to phenomenae in these region as well.
So, I would think few people will try to argue that even in chips microphonic effects can be present that exceed 10ppm at common music listening levels and they certain exceedd this level in ANY sort of capacitor.
Hence, I will contend easily that what makes no difference to the accuracy of killing other humans may very well make material differences to the process of providing people with musical enjoyment. As usual, it is much easier to kill and destroy than to something positive (1st law of thermodynamic).
Sayonara
Re: Re: Re: What about Piezoresistive Sensors
Hmmm, you make (giant) leaps of logic that astound me. Just because I called it a "fire control computer" you automagically ***-u-med that it works on two basic logic states and has most likely binary in/out or if analogue maybe with 8-bit precision.
You are so far off that Mr. Sayonara you could have been more accurate had you spoken from another world.
Kuei Yang Wang said:
Hmmm, you make (giant) leaps of logic that astound me. Just because I called it a "fire control computer" you automagically ***-u-med that it works on two basic logic states and has most likely binary in/out or if analogue maybe with 8-bit precision.
You are so far off that Mr. Sayonara you could have been more accurate had you spoken from another world.
Re: Re: Re: What about Piezoresistive Sensors
since your "analogue is so out of this world, I would leave it at that. But it surfaces to say that confusing the dynamic range of an analog system with resolution of a digital system isn't my cup of tea.
Somehow, my textbook has a different impression of what the 1st law of thermodynamics is different from yours but that's to be expected. BTW, having the s at the end is quite important, if you don't already know.
You may want to try your analogue on the 2nd law of thermodynamics (shall we say "entropy"?) as it would have been a closer proxy of what you had wanted to convey.
Kuei Yang Wang said:
since your "analogue is so out of this world, I would leave it at that. But it surfaces to say that confusing the dynamic range of an analog system with resolution of a digital system isn't my cup of tea.
Kuei Yang Wang said:
Somehow, my textbook has a different impression of what the 1st law of thermodynamics is different from yours but that's to be expected. BTW, having the s at the end is quite important, if you don't already know.
You may want to try your analogue on the 2nd law of thermodynamics (shall we say "entropy"?) as it would have been a closer proxy of what you had wanted to convey.
Re: Re: Re: Re: What about Piezoresistive Sensors
Konnichiwa,
You are right, the second law was meant.
Now, without revealing military secrets, you are basically saying that firing system works based on an analogue computer and has a resolution and bandwidth on it's analogue I/O that is eqaul or better than then the best Audio circuits? Yes?
I would find this rather extremely surprising but maybe the US Military has finally seen the light of analogue computing, though I'd guess it's at least two decades to late....
Sayonara
Konnichiwa,
millwood said:
You are right, the second law was meant.
Now, without revealing military secrets, you are basically saying that firing system works based on an analogue computer and has a resolution and bandwidth on it's analogue I/O that is eqaul or better than then the best Audio circuits? Yes?
I would find this rather extremely surprising but maybe the US Military has finally seen the light of analogue computing, though I'd guess it's at least two decades to late....
Sayonara
Getting back to the original intent of this thread. I really cant hear any difference in case materials,BUT i can as far as damping of the H/S and different H/Ss.
As i stated , i have gotten the best results from small, heavy rigid cases and a combo of damping/isolation of the H/S.
I tried one H/S that had small alum fins about 1.5" height, you could run your finger lightly over the fins and the amp would make a really horrible screach and distortion would last for about 30 sec. This leads me to believe that as far as the LM3875T is concerned proper damping of the H/S/chip is necessary.
No its not a scientific test , but...................................
ron
As i stated , i have gotten the best results from small, heavy rigid cases and a combo of damping/isolation of the H/S.
I tried one H/S that had small alum fins about 1.5" height, you could run your finger lightly over the fins and the amp would make a really horrible screach and distortion would last for about 30 sec. This leads me to believe that as far as the LM3875T is concerned proper damping of the H/S/chip is necessary.
No its not a scientific test , but...................................
ron
Re: Re: Re: What about Piezoresistive Sensors
Have you measured/demonstrated microphonic effects in semiconductors, and if so, what's the test setup?
Does anybody make strain gauges out of semiconductors? If this works reliably, why do people still make 'traditional' ones out of basically resistance wire? I ask merely for information.
Cheers
IH
Kuei Yang Wang said:
Have you measured/demonstrated microphonic effects in semiconductors, and if so, what's the test setup?
Does anybody make strain gauges out of semiconductors? If this works reliably, why do people still make 'traditional' ones out of basically resistance wire? I ask merely for information.
Cheers
IH
When i ran my fingers over the fins the fins would ring. The screach would happen at first for about 2 sec. then the sound would be distorted greatly with the distortion gradually tapering off.
All i am saying is this simple test exibiting ,to me anyway, that vibrations can affect a chip.I dont use the isolated chip , but if one is use its still physically connected to the H/S.This was on the LM3875T chip and i have no idea if other chips are affected in the same way.
If i wasent so lazy i would hook the whole thing up again and use the signal generator and scope to refine the test.But from the posts i see in here even hard test data means nothing compared to either opinions or what may have be stated in a text book where no test was performed.
ron
All i am saying is this simple test exibiting ,to me anyway, that vibrations can affect a chip.I dont use the isolated chip , but if one is use its still physically connected to the H/S.This was on the LM3875T chip and i have no idea if other chips are affected in the same way.
If i wasent so lazy i would hook the whole thing up again and use the signal generator and scope to refine the test.But from the posts i see in here even hard test data means nothing compared to either opinions or what may have be stated in a text book where no test was performed.
ron
Well Peter i have never tried the isolated version either, all i use is thermal grease and nylon screws as a hold down/interface.
I was at walmart last night and found some cutting boards that are some type of rigid plastic(?) and about .5" thick and cheap (cheap is my middle name) and thinking about it for a hold down arm combined with nylon screws.
I havent ordered the audio buss (used as the base of the H/S) yet, does any body know the material used for these, i am hoping its Cu and not some type of carbon steel.
It gold plated and looks cool anyway but i DONT want steel as a damping matl.
ron
I was at walmart last night and found some cutting boards that are some type of rigid plastic(?) and about .5" thick and cheap (cheap is my middle name) and thinking about it for a hold down arm combined with nylon screws.
I havent ordered the audio buss (used as the base of the H/S) yet, does any body know the material used for these, i am hoping its Cu and not some type of carbon steel.
It gold plated and looks cool anyway but i DONT want steel as a damping matl.
ron
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