We went over this a few weeks ago. In the limit of normal acoustic waves air can do IIRC 194dB or so with maximum rarefaction being a vacuum. Of course at this limit there is a LOT of 2nd harmonic as well as serious GBH to the listener. As usual these things go as power or the square of SPL and at any reasonable listening level it would be a stretch to say they matter.
The behavior of horn speakers at the throat and wind instruments involves shock waves and non-linear acoustics but once in the free field this drops off rapidly.
This has nothing to do with acoustic waves. "Got bass" in my college days meant blowing out candles with your woofer, one step over lighting farts.
In answer to my post stating:
He replied:
John Curl's Blowtorch preamplifier part III
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Thank you Scott. I take it that it means at listening level, driver to air (a compressible medium) interface does not develop measurable (or at least noticeable) distortion.
Just so that no one feels left out on knowing what is accurate reproduction (not production)...I will run over this again --->
You dont necessarily have to attend concerts and other acoustic performances. If you can, fine. All you need is a very familiar sound... use the sound of a person you live with to compare. Have that person stand between your speakers with a flat, low distortion microphone and have them recite something while you record it. During play-back of that familiar voice, compare the loudspeaker's sound to the "live" sound you heard and know.
This method takes in all of your acoustic, environment, atmospheric and electronics. And, with your own ears and knowledge of the 'real' sound - voice - you can easily tell if they both sound the same or not.
You can use various people... male, female and children to widen the midrange area of reproduction. Of course, you can do the same with an acoustic instrument played in the same location as voice in your listening room.
You can even experiment with adding H2 and/or H3 levels on playback and see how that affects the accuracy of reproduction.
THx-RNMarsh
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You dont necessarily have to attend concerts and other acoustic performances. If you can, fine. All you need is a very familiar sound... use the sound of a person you live with to compare. Have that person stand between your speakers with a flat, low distortion microphone and have them recite something while you record it. During play-back of that familiar voice, compare the loudspeaker's sound to the "live" sound you heard and know.
This method takes in all of your acoustic, environment, atmospheric and electronics. And, with your own ears and knowledge of the 'real' sound - voice - you can easily tell if they both sound the same or not.
You can use various people... male, female and children to widen the midrange area of reproduction. Of course, you can do the same with an acoustic instrument played in the same location as voice in your listening room.
You can even experiment with adding H2 and/or H3 levels on playback and see how that affects the accuracy of reproduction.
THx-RNMarsh
.
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Well, since you cant figure it out on your own, Scott.... i'll tell you...
CAD.... Digital.... DAC....ADC... many places in 'audio' where this Normal behavior of high dielectric constant parts are used can give less than expected results if you dont consider the affect of DC on them.
Example .... You may think you are bypassing at the pin with a .1 mfd but really are doing so with an effective .01 mfd. Thus, giving results that are not expected..... increased noise and instability etc.
I'll leave it up to others to find other apps and other caps with similar Normal behavior of reduced C with dc on them.
THx-RNMarsh
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Thank you Richard for your cap distortion input. Many here tend to discount the problems with small size/high cap ceramics. The page you contributed was one of the most specific and technical on the subject. Of course it can be measured, AND it adds distortion at low frequencies if used as a coupling cap, like Sony, etc tend to add as a matter of fact to their normal electronics.
Except your cite did not have any data even remotely showing an order of magnitude change with normal bias. Typical X7R is 10% or so and you don't use them where noise and instability matter. You are just making stuff up, especially noise what on earth do you mean?
I use X7R ceramic bypass capacitors in situations where the design needs a "BFC", in other words, a Big Frriggin Capacitor, and I want to fit it into a small space. For example, capacitor "C4" in the attached schematic is an X7R ceramic capacitor. You can see that it's a bypass capacitor, its job is to keep the voltage across the LED rock solid and constant, while input square waves with 5 nsec rise time are jerking the Ccb capacitances of devices Q1 and Q3 up and down, ferociously. Circuit works well, measures good, sounds excellent.
Do I care whether the capacitance of C4 changes by 25% when the voltage across it changes? Nope, as long as it remains Frrigin Big. Do I care whether the capacitance of C4 changes by XX% when the ambient temperature changes from -25C to +75C? Nope, as long as it remains Frriggin Big. All I want is C4 >>> Ccb; in other words, C4 is a Big Frriggin Capacitor. Of course the excellently low ESR of ceramic capacitors is also a benefit in bypass situations like this one.
On the other hand, for coupling capacitor C1 I chose a Nichicon UES green-sleeve "MUSE" bipolar electrolytic. It's not a bypass capacitor though.
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Do I care whether the capacitance of C4 changes by 25% when the voltage across it changes? Nope, as long as it remains Frrigin Big. Do I care whether the capacitance of C4 changes by XX% when the ambient temperature changes from -25C to +75C? Nope, as long as it remains Frriggin Big. All I want is C4 >>> Ccb; in other words, C4 is a Big Frriggin Capacitor. Of course the excellently low ESR of ceramic capacitors is also a benefit in bypass situations like this one.
On the other hand, for coupling capacitor C1 I chose a Nichicon UES green-sleeve "MUSE" bipolar electrolytic. It's not a bypass capacitor though.
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