On my view, it is like digital photography. If you own a 42Mpx body (kinda oversampling ;-) and a lens that is not too sharp, the blur of the lens is enough to get rid of anti aliasing filter.
If you own a 24 Mpx body and a super sharp lens, difficult to avoid the filter.
I'm not, far from it, a digital guy. If i have understood well, the advantage of oversampling or 96Khz is not so much the extended frequency range, but the fact that we can use a less sharp filter, situated higher in frequency, so, having less impact on the phase curve in the audible range.
The electronic of my current feedback amp goes up to 6Mhz, while there is an input filter at around 100KHz. So, I'm not terrified about HF IMDs ;-)
An other thought: at the time we were recording at 48Khz, I was not too much annoyed by the AD filters, as we made our mixes for they sound nice with them ;-)
Purists should draw the conclusions that matter.
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Joke appart, are-we really annoyed by the Reed relay magnetic fields at line levels ?
Do-you really feel a difference with a strait wire, or it is just a quest of theoretical perfection that do not exists in our universe ?
Whose line levels? Pro, Consumer, IEC or Red Book?
Some audiophile or even consumer amplifiers have gains much higher than the nominal AV20. So a consumer may actually be using preamplifier output levels of less than .01 V RMS.
So a soft passage could be .0001V RMS and allow instantaneous hearing threshold 60 dB below that... Just maybe an issue.
A pro could easily see peak levels of 10 V RMS. So not much worry.
On my side, I use 1V 10K for home, and 3,1 V 600 Ohms for pro.
I dont commute anything at the output of my preamp, and, if the sensivity of my set (amplifier+speakers were too high), I would have thought to build an attenuator ;-)
Yes, that can be expressed as constant power per decade for PN and constant power per bandwidth for WN ........or something like that....it's late.
The result is that most of the energy/amplitude is in the lows and very little in the highs.
Woofers can measurably change most certainly, tweeters also I reckon but never get exercised with PN, the HF peak transient content is the value of the M-Noise waveform which seeks to mimic HF crest factor of music.
Dan.
Richard appeared to be saying that the tweeters would offset with hf content above capability. I think he was saying the amp would offset due to out of band content. Well, at least I hope that was what he was trying to say.
Never measured such, but assume it could happen.
Jn
Verified each time (20+) we worked on prototypes of enclosures.
We used to let them move for 24H+ at infrason frequency (~10Hz for the comfort of people) and at the limit of their excursion. Never tune a bass reflex with a brand new speaker out of the box.
Idem, never measured Thiel and Small of a tweeter, but, as we used compensation networks to flatten the impedance curve on several prototypes, we don't noticed any major change after one year in a show room.
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The problem is that you have to design for folks whose elevator doesn't stop at all the floors.
Most consumer audio power amplifiers use a potentiometer for the volume control, so using it at less than full setting reduces the signal to noise ratio.
That's cool, transformers can distort but probably not at these levels. I used some old UTC (nice shielded military surplus) PA output transformers backwards to make a Schumann resonance receiver.
I used to see it with woofers and always attributed it to the drivers,
until one time happened to have a scope handy and lo and behold !
This was amps with capacitor bootstrap back to the Vas load and some
way I associated that ........... But ?????????
I am not sure to understand you. What level of distortion come from a reed relay at, say 1V ? The ratio will remain constant, whatever the volume control, because, usually, it is to choose the source before the volume.
Of course, we should consider-it differently with those volume controls via combinations of attenuators set by relais ?
The reason of my question about reed is just because they are cheap, little, and free from oxydation.
In my case waaaaay lower. But I'm fretting the input side. I have always wondered why for many years there was so much relay fear in domestic audio tho.
Even here on diyAudio if you can imagine it!
Have a look at one or more of the threads here, entitled diyAudio <<project XYZ>> Build Guide. These are step by step sets of photos, showing how you go from a bare PCB that you purchased from the diyAudio Store, to a finished working <<project XYZ>>. Sort of a Monkey See, Monkey Do tutorial. But have a look at the questions that are asked. Cowabunga! Some question askers are so unencumbered by common sense, that they demonstrate "their elevator doesn't stop at MOST of the floors."
On a thread for an amp that I helped get into the Store, one guy asked a super weird question about the PCBs he received from the store. After some back and forth weirdness-decoding, it became clear that what he ACTUALLY wanted, was someone to tell him how to distinguish between the "Component Side" and the "Solder Side" of a two layer, thru hole, printed circuit board. This is a guy who successfully built other amps previously, he says. Cowabunga.
Distortion is different than signal to noise. Power aplifiers can easily have signal to noise ratios better than 120 dB full output to noise floor. When you turn down an input potentiometer the noise floor does not go down. It takes more voltage from the preamplifier go get full output.
As you turn up the preamp you also turn up the noise it sends.
In practice the first gain stage often sets the limit to signal to noise ratio. One mearly tries to not screw it up in the following stages. So gain staging is how you do that. Having too much gain is a good way to screw things up.
In some pro gear the gain is actually changed. That is what that funny gain trim knob on top of the input channel on the console is used for. It is a variable resistor used as a gain changer. A variable resistor used as a potentiometer is a different thing.
Yes people often call a variable resistor a pot but it is not, won't even hold water if you try to cook with it.
A potentiometer is a variable resistor fed from a voltage source. As you adjust it you vary the output potential, usually measured in volts.
As specifically about reed relay distortion figure about 1 uV of distortion if the coil is feed from perfect DC. Tested at a signal level of 10mV.
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My question was not about noise: of course, if we have a bad contact witch generate noise, it will be amplified with the volume (but signal noise remain constant).
I don't had noise issues with reed relais unless they have a problem. What about you ?
My question was about suspected distortion caused by the magnetic field on this short wire length inside the sealed glass tube.
J.C. don't like them, but did not explained why. Not enough expensive ?
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