As my only experience with horns is in PA applications (where things like damping factor are rather secondary factors), so I am in no position to argue with you on that point - all I know is that some people I know and respect don't share your view. Do you have any references to support your rather strong statement?
Don't agree. I explained why.
And that is experienced with decades on 'hi end' horns, on my side.
Horns are usually used on a large bandwidth, means you don't like to make them fractionate at HF.
They are damped by design on all the surface of the membrane by the compression. You do not want to add a risk to fractionate, trying to damp them with high slew rate signals applied to their coil at the edge of the membrane.
More generally, damping factor is really useful only at resonance.
You do not use a horn driver at his resonance, if you avoid distortion.
It is like large band speakers: They definitively don't like electric damping, because you use them above the frequency where they fractionate, and work better with a high impedance amp, damping their resonance by a bass reflex or a 1/4 wave enclosure.
More damping to them, more you ear the "membrane material" and get a tortured frequency curve.
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OK - as I stated, my experience with horns is mostly in the PA area. One of the horns I was involved in long ago was a 3 m x 2 m x 1 m concrete horn, with 2 15" drivers. They definitely benefited from damping.
So, in order to get this discussion back to nCores, can we agree that a resistor on the output of the nCore definitely spoils the excellent damping ratio of the nCores. It might or might not matter with horns - but anyone using horn speakers probably has a strong view of their own on that matter.
Ok, but where is the part on amp dampening factor influence in horn system?????
The discussion was: if you have high sensitivity compression drivers and you want to use an overpowered Ncore without hiss, should you reduce the gain of it ( 3 db) or is it possible to use a lpad or series resistor without serious quality loss.
I have never liked them for domestic listening (horns) , over 6m , well Ok ...
Nowhere - but the part I found interesting was the "The reader will note many areas where I disagree with Mr. Kolbrek, but mostly I disagree with continuing to propagate concepts that are not based in reliable science"
And within those narrow confines, yes, I am willing to admit that there probably won't be serious quality loss.
I confirm. I was talking about compression drivers. Long time ago, I used JBL cones drivers in horns enclosures at the time i was in charge of a big rental PA company and indeed, they needed good electronic damping.
For my understanding, if this is the case
then how can this be the case?
Isn't that exactly the reason why you want a high damping factor/low output impedance, to absorb currents from the driver that are nothing to do with the signal being fed to the driver?
No it's not. A class d amp doesn't have any quantisation in its amplitude, it is completely linear. It could be argued that there is quantisation in its frequency resolution because of its switching frequency, but not in its amplitude
Lowering its power supply voltage won't change its gain or noise characteristics, it will lower its maximum power because it will clip earlier. It may/will also change its open loop linearity at the desired (low) operating power. If we assume that the amplifier is more linear about its centre point, then it is more linear at lower amplitudes than higher amplitudes and so lowering the supply voltage lowers the point/power at which these 'higher amplitude' non-linearities will occur
ChrisPA, a class D amp is a width modulation of a square pulse. The width is set by a comparator between a triangle signal and the input signal. Its precision (so its definition or distortion) depend of the internal noise and the level of the input signal (you get better precision if you compare V than µV).
Reducing the voltage of the pulses (reducing the voltage feeding the power Mosfet) reduce the power (less voltage) without changing the widths of the pulses. The output noise will be reduced in the same time.
It is obvious.
It will not clip 'earlier' with the input signal. It will just reduce the acoustic power, Like if you used a less efficient speaker. That we want with a high efficiency speaker like a compression driver+horn.
Look at the distortion+noise curve of an amp: it will increase as the level decreases, at least because the amp's noise.
To explain the things with other words, instead of using 0 to 5% of the modulation range in normal work, you will use 0 to 30% for the same acoustic level. See what i mean ?
About compression driver, the membrane is damped by the high pressure a little like if it was in water. The little volume of air between the phase plug and the membrane oppose a great force against movements. The excursion of the membrane is very little, for the same acoustic level compared at the one you would need in free air.
http://www.meyersound.com/news/press/images/meyer_diag.l.gif
Reducing the voltage of the pulses (reducing the voltage feeding the power Mosfet) reduce the power (less voltage) without changing the widths of the pulses. The output noise will be reduced in the same time.
It is obvious.
It will not clip 'earlier' with the input signal. It will just reduce the acoustic power, Like if you used a less efficient speaker. That we want with a high efficiency speaker like a compression driver+horn.
Look at the distortion+noise curve of an amp: it will increase as the level decreases, at least because the amp's noise.
To explain the things with other words, instead of using 0 to 5% of the modulation range in normal work, you will use 0 to 30% for the same acoustic level. See what i mean ?
About compression driver, the membrane is damped by the high pressure a little like if it was in water. The little volume of air between the phase plug and the membrane oppose a great force against movements. The excursion of the membrane is very little, for the same acoustic level compared at the one you would need in free air.
http://www.meyersound.com/news/press/images/meyer_diag.l.gif
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Why would reducing the voltage reduce noise? What you want to do is decrease *gain*.
If you reduce the voltage, the point where the amp will clip (by running out of ability to produce the required amplitude/power) will happen sooner if you keep the gain constant but reduce the voltage available.
Reducing the *gain* will produce less acoustic power, but that has nothing to do with the available voltage.
Yes. And noise does not decrease with decreasing voltage, it decreases with decreasing gain.
And why would that affect noise and/or distortion?
when you decrease gain, you decrease noise, because the same modulated noise will be carried by a lower voltage.
i don't understand why this is so hard to understand.
If you want to reduce the output level of a DAC, you have 3 solutions
1- Set an attenuator. (But you will increase output impedance after-it).
2- Reduce the level in the digital domain, but it will reduce the definition (less bits)
3- Reduce the analog voltage reference: each bit will have a lower voltage, but you will keep the definition.
Ok, that's enough about the question, i think.
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So true!
everyone is listening for different parameters with different ears
most speakers loose 99% of whatever you feed them
seems like the overall sport in hi-fi engineering these days lies in solving errors everywhere else than where they occurs in the first place
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