Well, for starters, is all octaves created equal, regarding audibility of harmonic distortion?
Is the threshold the same for all human beings ?
For what i understand, multi-way will help in that regards by dividing the tasks among drivers that are in their comfort zones. But to what extent?
Is the threshold the same for all human beings ?
For what i understand, multi-way will help in that regards by dividing the tasks among drivers that are in their comfort zones. But to what extent?
Would it be silly to say that 5% THD wouldn't be audible by the vast majority of people for any frequencies below 35hz ?
The main cause of distortion in, say, a 5" speaker is excursion of the coil in the magnet gap. The more it moves, the more it distorts. It's not linear.
By passing bass duties onto a bigger woofer, the 5" doesn't move so much. So distorts less.
You are also keeping the drivers in their comfort zone, as you say. Much easier to get the cone breakup region well down in output level. With an 8" cone breakup lurks at 3kHz. With a 5" it's up around 8kHz.
A tweeter will always go louder crossed at say, 3.5kHz than at 2kHz. So, yes, 3 way is good. It goes loud without effort and keeps distortion lower. It doesn't much matter what the distortion figure is, the main thing is good engineering can reduce it.
People find this controversial, but an easy impedance, free of peaks and troughs keeps an amplifier in its comfort zone too. So cheap amps can work well with a well designed 3 way.
By passing bass duties onto a bigger woofer, the 5" doesn't move so much. So distorts less.
You are also keeping the drivers in their comfort zone, as you say. Much easier to get the cone breakup region well down in output level. With an 8" cone breakup lurks at 3kHz. With a 5" it's up around 8kHz.
A tweeter will always go louder crossed at say, 3.5kHz than at 2kHz. So, yes, 3 way is good. It goes loud without effort and keeps distortion lower. It doesn't much matter what the distortion figure is, the main thing is good engineering can reduce it.
People find this controversial, but an easy impedance, free of peaks and troughs keeps an amplifier in its comfort zone too. So cheap amps can work well with a well designed 3 way.
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Another source of distortion is reckoned to be high mechanical loss in cones.
Those modern heavy cones with high mass can be very flat on frequency response, but store a lot of energy, ruining clean transients and sounding dull.
This is revealed in the waterfall. Which is not something you often see but shows stored energy. One source of a big delay is steep rolloff from the filter, or just a natural steep rolloff in the driver.
It sounds like a sort of ringing on certain notes. Soft domes aren't my cup of tea. I think we can see problems in the waterfall despite the flat response.
Those modern heavy cones with high mass can be very flat on frequency response, but store a lot of energy, ruining clean transients and sounding dull.
This is revealed in the waterfall. Which is not something you often see but shows stored energy. One source of a big delay is steep rolloff from the filter, or just a natural steep rolloff in the driver.
It sounds like a sort of ringing on certain notes. Soft domes aren't my cup of tea. I think we can see problems in the waterfall despite the flat response.
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I dunno what speakers you are referring to, but I would say that a "good" design will stay under 1% unless input power is high. By "good" I mean by a reputable company or informed DIYer. Of course the exception is in the lower bass (below 80 Hz), where excursion starts to become high so suspension, Bl, and other non-linearities are very difficult to design around. This is one argument for a 3-way with a dedicated woofer used up to 150-200 Hz. I can pretty easily perceive >1% the distortion in most 2-way systems (e.g. 6.5" woofer, 1" tweeter) when they are being played loud using music with above average bass content (I don't mean car audio demo tracks, either!).
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Maybe those "heavy cone" drivers are just being used too high in frequency? Like you pointed out, it makes sense to use some kind of measurement of energy storage as part of a "test suite" to determine within what frequency range a driver is suitable.
Eminence must be the masters of the lighter cone and unlossy surrounds.
But Two ways don't go very loud is my conclusion. 😀
Though I've had a good time with 8" bass.
I did see some figures that said reflex bass distorts a lot more than closed box. But I don't know really. Strengths and weaknesses really.
The modern trend is reflex, because the cabinet is smaller. And cheaper.
But Two ways don't go very loud is my conclusion. 😀
Though I've had a good time with 8" bass.
I did see some figures that said reflex bass distorts a lot more than closed box. But I don't know really. Strengths and weaknesses really.
The modern trend is reflex, because the cabinet is smaller. And cheaper.
I tend to hear it more as freq.s decrease.. it's not about source reproduction so much as reproduction of hall sound. (..I can't really hear it change source reproduction unless it's almost doubling at these lower freq.s. Whereas I can easily hear a change in hall sound reproduction, particularly real or artificial space-dimensions (like a cathedral for a choir), though this is without substantive negative effects for a particular listening position relative to modal peaks generated by the listening room. If that happens, then it can be tough to discern much difference difference other than the obvious increase in pressure.)
Most likely, but is low distortion more important than imagining in convincing reproduction?
..a good source for information:
Measurement and Perception of Regular Loudspeaker Distortion
..in particular looking at the section starting with "Regular Nonlinear Distortion".
Note where problems "crop-up" relative to freq. for a driver and how pass-banding (or limiting the drivers operation with filtration) could help with these problems. Also keep in mind the design of the driver.
ex. midrange drivers typically have lower inductance levels because of the smaller VC, but might also have higher levels of diaphragm bending because of a much lighter/flexible cone and surround.
Measurement and Perception of Regular Loudspeaker Distortion
..in particular looking at the section starting with "Regular Nonlinear Distortion".
Note where problems "crop-up" relative to freq. for a driver and how pass-banding (or limiting the drivers operation with filtration) could help with these problems. Also keep in mind the design of the driver.
ex. midrange drivers typically have lower inductance levels because of the smaller VC, but might also have higher levels of diaphragm bending because of a much lighter/flexible cone and surround.
The question ignores the difference between a measurement method and an operational scenario. You don't listen to "5%" distortion, EVER, unless you listen to steady sine waves. Music or even speech through a home speaker is from being driven with average power in the region of 0.01W, with instantaneous peaks that can go into 100s of Watts. Maybe the question could be "can you hear distortion from a speaker when driven by a sinewave level equal to some voltage peak" but that still doesn't really mean a lot.
Harmonic distortion is just a relatively easy way to test for nonlinearities, to verify decent engineering and no major build flaws, it's not a description of performance when reproducing music. Most of the distortion you'd hear from nonlinearities would be from intermodulation distortion (of which there very many different kinds) anyway, and if you quantify it you also have to state at what frequencies and levels (of every one of the driving tones). Which again isn't a music reproduction situation, since drive levels playing music varies from zero (silence) to full level peaks.
Harmonic distortion is just a relatively easy way to test for nonlinearities, to verify decent engineering and no major build flaws, it's not a description of performance when reproducing music. Most of the distortion you'd hear from nonlinearities would be from intermodulation distortion (of which there very many different kinds) anyway, and if you quantify it you also have to state at what frequencies and levels (of every one of the driving tones). Which again isn't a music reproduction situation, since drive levels playing music varies from zero (silence) to full level peaks.
A little note of clarification here. It's true that average power levels tend to be lower than we think. Most dynamic digital recordings have a range of 18-20 dB from the average to the peak levels. Good classical recordings more, most rock and pop, less. 16 dB below peak is another typical mastering level.
Looking at my long running voltage survey here on diyAudio, we see that 70% of those in the poll report a test signal level of 5V or lower. That means on most tracks they will be running an average power of about 0.8 W, tops.
High efficiency systems and small rooms might be averaging 1/10 that power. Therefore I would say that most people are running at between 0.08 to 0.8 watts at their loudest volume settings. That means (rounding up) between 10 and 100 watts on the peaks*.
As Bill says, the bulk of the music is in the factional watt range.
*Peaks are not evenly distributed along the spectrum. See here.
Spectrum of Musical Genres
Hi Jon,
So we're clear that all drivers are band-pass devices, right? That is they have a limit to the upper and lower frequency response, maximum output, and dispersion.
A multi-way speaker attempts to get the best compromise by using drivers that are optimal at each frequency band. This means even dispersion, low distortion, wide and flat frequency range, as well as good dynamic range.
So we're clear that all drivers are band-pass devices, right? That is they have a limit to the upper and lower frequency response, maximum output, and dispersion.
A multi-way speaker attempts to get the best compromise by using drivers that are optimal at each frequency band. This means even dispersion, low distortion, wide and flat frequency range, as well as good dynamic range.
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Only for distortion of (forgive me for the trivial language) a difficult-to-detect nature.
For example, audibility of 2nd-order harmonic distortion alone requires a very high level to detect (probably the 25% you refer to), but it would be quite easy to detect 7th-order harmonic distortion - within the limits of human hearing of course.
All the harmonics are going to exist to a varying degree, diminishing in amplitude as the order goes up
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