i just found out, it uses power transformer lamination and includes the formula for the equivalent air gap interested to try it. https://ttradio.net/discussion-and-test-of-single-ended-output-transformer/
Still unclear to me. I thought reactance and impedance, typically represented as Z, are two different words for the same thing. Impedance (or reactance) can be inductive or capacitive. I also thought that R is Ohmic resistance. Then what it is about, speaker or transformer winding?
Transformer distortion is coming from distorted magnetizing current passing through equivalent primary circuit series resistance. Low series resistance, particularly low driving impedance, results in low distortion. Magnetizing current distortion is largely due to hysteresis, so lower hysteresis results in lower distortion. Transformer distortion is negligible if its primary has high inductance and its core has low hysteresis.
I don't understand in what way crossover order can affect transformer distortion.
as far as I know steel is made of iron and carbon. it is no longer iron but steel.
You also answered your own question reactance is inductive, but resistance is not, and impedance can be both.
don't forget the tube also has resistance.
correct me if i'm wrong.
You also answered your own question reactance is inductive, but resistance is not, and impedance can be both.
don't forget the tube also has resistance.
correct me if i'm wrong.
It is because of that distorted magnetizing current. The problem is that magnetizing current GROWS at low frequency (compared to mid frequency) because of the limited inductance. Go low enough in frequency and the magnetizing inductance becomes a heavier load than the speaker. This is what causes the low frequency to roll off. And to distort. Not only does it distort the offending bass tone, but everything else that’s running thought it at the same time. The tube doesn’t care that the current due to the magnetizing inductance is out of phase and not delivering real power to the load, ether. It still has to deliver that very real current (to it, anyway).
If the transformer can’t handle it, you’ve just got to keep the bass out of it.
Now I understand what you mean. It all boils down to calculating how much primary inductance is needed for specified distortion level at given low frequency. Lower order crossover will need more inductance because it attenuates lower frequencies to a lesser extent.
To the point above, 1st order crossover does not increase distortion, it just requires more transformer inductance for the same distortion level.
To the point above, 1st order crossover does not increase distortion, it just requires more transformer inductance for the same distortion level.
The tube sees the load impedance Z.
At low frequencies the transformer primary inductance enters the picture more and more.
The imaginary, low frequency inductive part of the transformed impedance Z, is XL= primary-L 2 pii f
The real, resistive part of Z is R.
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true, the 1st order in itself is not direct responsible for the distortion and higher inductance shifts the picture. But remember, a transformer is BW limited and what you add at the low end will have an impact at the high end. better to use more than 6db attenuation in the first place . Anyway, together with the transformer's inductance it will turn at some point into some form of second order filter with distortion, and this time the combined "high pass" is responsible for the distortion.
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reactance can be inductive or capacitive
X= imaginary part of the impedance
L= inductance
XL= reactance of an inductor at a certain frequency
R= real resistance.
Z= impedance
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you say XL not XC.
Common R = Resistance
what about the internal resistance of the tube,?? not parallel??
Although not wishing to complicate the issues unnecessarily, sometimes partial understandings are so limiting as to give wrong results rather than just slightly-not-right results, and this is almost always the case with the vast majority of commercial subwoofers and their crossovers, and this trickles down to DIY. The saving grace is that we humans don't really hear very well down there, so can forgive a lot. And there's a lot to forgive.
There are three confounding problems to mating a (or a pair, or more) subwoofer(s) to music-range speakers. First is that it/they are in a different physical location in the room, so have a different arrival time ("phase") than the music-range speakers. Rooms of sizes that most of us can afford to live in are full of resonances in the crossover range, so we can usually forgive the errors caused.
Second problem is that all of the speakers involved, especially the music-range but also to lesser extent the subwoofer(s), have their own fundamental, meaning mass x compliance, resonances very near, or within the crossover region. Their individual "filter functions" each contribute to the sound in the room, independent from, but adding to, any electrical "crossover" filters. The actual crossover function that occurs is the sum [yes, mathematically the product, but this is 101] of the electrical crossover and the drivers' mechanical/acoustical hi-pass crossover. One conclusion from this is that there can be no actual (acoustical) crossover ultimately shallower than 2 pole (12dB/oct) because fundamental mechanical resonances are 2 pole. Another is that, because the mechanical resonances tend to fall within an octave, and almost certainly within two octaves, of the intended crossover frequency, they will tend to dominate the summed filter function of the actual acoustic output. Yet somehow, they're ignored in discussions; I blame the commercial necessity to not wish to try to explain the issues to prospective purchasers - I certainly wouldn't want to.
Third problem is the most worrying to me: what is the purpose of adding a subwoofer? If the music-range speakers play the music, then what does the subwoofer play? If it's not music, why do I want it? Or, if the music range speakers don't play all of the music, why not? If it's really a woofer, treat it as such and optimize the speaker system to have real woofers, taking advantage of that. Grump, grump, grump.
All good fortune, and grumpily yours,
Chris
There are three confounding problems to mating a (or a pair, or more) subwoofer(s) to music-range speakers. First is that it/they are in a different physical location in the room, so have a different arrival time ("phase") than the music-range speakers. Rooms of sizes that most of us can afford to live in are full of resonances in the crossover range, so we can usually forgive the errors caused.
Second problem is that all of the speakers involved, especially the music-range but also to lesser extent the subwoofer(s), have their own fundamental, meaning mass x compliance, resonances very near, or within the crossover region. Their individual "filter functions" each contribute to the sound in the room, independent from, but adding to, any electrical "crossover" filters. The actual crossover function that occurs is the sum [yes, mathematically the product, but this is 101] of the electrical crossover and the drivers' mechanical/acoustical hi-pass crossover. One conclusion from this is that there can be no actual (acoustical) crossover ultimately shallower than 2 pole (12dB/oct) because fundamental mechanical resonances are 2 pole. Another is that, because the mechanical resonances tend to fall within an octave, and almost certainly within two octaves, of the intended crossover frequency, they will tend to dominate the summed filter function of the actual acoustic output. Yet somehow, they're ignored in discussions; I blame the commercial necessity to not wish to try to explain the issues to prospective purchasers - I certainly wouldn't want to.
Third problem is the most worrying to me: what is the purpose of adding a subwoofer? If the music-range speakers play the music, then what does the subwoofer play? If it's not music, why do I want it? Or, if the music range speakers don't play all of the music, why not? If it's really a woofer, treat it as such and optimize the speaker system to have real woofers, taking advantage of that. Grump, grump, grump.
All good fortune, and grumpily yours,
Chris
Many good points already made; no need to belabor them.
Maybe it's just me, but what the OP originally described is something I would never consider, even with the most desperate/compelling motive(s). There's no reason to consider the shortcomings of an output transformer, as long as you don't feed that into another power amp! Just put on the big boy pants, fit the filter/crossover at line level at the power amp inputs, and enjoy the sound of the best-possible configuration.
Cheers (a little grumpily 😉 )
Maybe it's just me, but what the OP originally described is something I would never consider, even with the most desperate/compelling motive(s). There's no reason to consider the shortcomings of an output transformer, as long as you don't feed that into another power amp! Just put on the big boy pants, fit the filter/crossover at line level at the power amp inputs, and enjoy the sound of the best-possible configuration.
Cheers (a little grumpily 😉 )
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No, Zp, the impedance the tube works into, is the reflected primary impedance, by definition Z includes R
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XL is the reactive part (reactance) of an inductor, XC is the reactive part (reactance) of a capacitator, both are reactances,
concerning the XL/R ratio, the internal resistance of the tube is in parallel with the plate load impedance Zp.
The excellence of the 24dB/Octave Linkwitz Riley filter is well known.
And so is the correct implementation of a 6dB/Octave filter and excellent drivers.
You should note that Linkwitz last speaker multi way design had less than 4 feet from the 'sub' woofers to the tweeter at the top.
I am sure he made all the correct time and phase alignment calculations for that system.
And so is the correct implementation of a 6dB/Octave filter and excellent drivers.
You should note that Linkwitz last speaker multi way design had less than 4 feet from the 'sub' woofers to the tweeter at the top.
I am sure he made all the correct time and phase alignment calculations for that system.
May I ask, how would that correct implementation of a -6db/octave filter look like with a mid/high speaker? I would not like to have my mid/hf response modulated with the high amplitude low frequencies the filter is uncapable to keep out. Also, at some point, your mid/hf speaker will meet his resonance frequency and if that happens, without proper electro/mechanical damping, your mid/high speaker is easily toast. Furthermore, why would you want to subject your mid/high speaker to additional low frequency mechanical and thermal load ?