I'm pretty sure this is correct as long as the tweeter is directly driven from an amp with a reasonable damping factor. Any network in parallel to the tweeter won't change the voltage across the tweeter and therefore won't have any effect on it.
But then again I've been wrong before plenty of times, so please correct me if I'm wrong.
But then again I've been wrong before plenty of times, so please correct me if I'm wrong.
wrong yet again i believe
And not for the last time either (but I could be wrong)
Educate me......
Most speaker wires have significant inductance, so a shunt network (at the driver terminals) can indeed alter the tweeter response.
I just had a look for what sort of inductance we’d be looking at and I see that Rod Elliot provides some figures of between 32 and 626 nH per meter, which is pretty low compared to the component values used in a typical compensation. Wikipedia quotes lamp cord at 0.2 uH/foot Speaker wire - Wikipedia, the free encyclopedia
My understanding of the compensation in parallel with the tweeter terminals is to flatten the load presented by the speaker to a passive crossover around the speaker resonance frequency, so it is effectively a part of the passive crossover. It is not there to prevent HF oscillation. Is this incorrect? Does it also 'compensate' for cable inductance?
My understanding of the compensation in parallel with the tweeter terminals is to flatten the load presented by the speaker to a passive crossover around the speaker resonance frequency, so it is effectively a part of the passive crossover. It is not there to prevent HF oscillation. Is this incorrect? Does it also 'compensate' for cable inductance?
Your logic is sound, as long as the loudspeaker cable is of adequate quality. Its impedance must be << that of the driver.
Compensation is unnecessary in a passive design too, unless resonance is influencing high-pass components to inadequately suppress driver level.
Unless you're using a poor amp design, like tubephiles often do.
Very important point. One of the benefits of going active is the elimination of any loss-inducing factors between power amplifier and driver.
OK, thanks Shaun and RockLee for the confirmation.
I posed the question because I recently came across the data sheet for the tweeter I used in my active MTM setup that I built some years ago, and saw a note about the importance of adding compensation (RLC) to the tweeter particularly at higher power. I figured I could continue to ignore its absence ......but the question kept niggling me.
I posed the question because I recently came across the data sheet for the tweeter I used in my active MTM setup that I built some years ago, and saw a note about the importance of adding compensation (RLC) to the tweeter particularly at higher power. I figured I could continue to ignore its absence ......but the question kept niggling me.
What the heck are you guys talking about??
1) there is nothing "wrong" with most tube amps.
2) there are things "wrong" with many solid state amps. (different things)
3) the "zobel" on a tweeter generally speaking is not to compensate for cables.
4) the primary intent of a "zobel" is for impedance compensation, not freq response
5) frequency response compensation is a different thing.
The question is what is the purpose and aim of "compensation"?
No standard electronic xover is going to compensate for the impedance/reactance effect upon the amplifier.
The electronic xover is likely to be able to provide equal or better (if it cleverly done DSP) frequency response compensation compared to "RLC" approaches. But the question then is if you can hear DSP or not... (you decide).
In case you do not think that there is any effect due to impedance and especially reactance, take a look at the output of your amp when faced with an inductive or capacitive load. Then after you do that, go compare how things look with your typical loop feedback amp (tube or solid state) and with your non-loop feedback amp. Like one of those "poor amp design, like tubephiles often do"?
A good test is to look at a square wave with these reactive loads.
Oh, wait, well... maybe a zobel is a good idea then?
It flattens the reactance...
Yeah, it is supposed to, but maybe it doesn't sound good.
_-_-
1) there is nothing "wrong" with most tube amps.
2) there are things "wrong" with many solid state amps. (different things)
3) the "zobel" on a tweeter generally speaking is not to compensate for cables.
4) the primary intent of a "zobel" is for impedance compensation, not freq response
5) frequency response compensation is a different thing.
The question is what is the purpose and aim of "compensation"?
No standard electronic xover is going to compensate for the impedance/reactance effect upon the amplifier.
The electronic xover is likely to be able to provide equal or better (if it cleverly done DSP) frequency response compensation compared to "RLC" approaches. But the question then is if you can hear DSP or not... (you decide).
In case you do not think that there is any effect due to impedance and especially reactance, take a look at the output of your amp when faced with an inductive or capacitive load. Then after you do that, go compare how things look with your typical loop feedback amp (tube or solid state) and with your non-loop feedback amp. Like one of those "poor amp design, like tubephiles often do"?
A good test is to look at a square wave with these reactive loads.
Oh, wait, well... maybe a zobel is a good idea then?
It flattens the reactance...
Yeah, it is supposed to, but maybe it doesn't sound good.
_-_-
Sheesh, relax, nobody said all valve amps are lousy - In fact I've heard that some of the better ones almost work properly, just like normal amps. Well OK, not quite, but, well, um... ok maybe there is something "wrong" with them, but that doesn't have to be a bad thing does it?
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my comment was about going active eliminates the need for passive crossover, that's for sure
but zobel, RC network compensating the rising impedance of the tweeter has nothing to do with active vs passive crossover
if the zobel is needed and is beneficiary, then it should be used no matter what crossover
period
now when it comes to the tubes vs solid state, common guys, we had many of these ot discussions, they lead nowhere, they can be fun for sure...
but zobel, RC network compensating the rising impedance of the tweeter has nothing to do with active vs passive crossover
if the zobel is needed and is beneficiary, then it should be used no matter what crossover
period
now when it comes to the tubes vs solid state, common guys, we had many of these ot discussions, they lead nowhere, they can be fun for sure...
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godfrey, I gave the exact quote - "often" was the operative word.
The idea that solid state is automatically better, I think is false, and very dependent upon the precise and exact application. There are "good" and "bad" amps of all types. Also and more importantly, there are "good" and "bad" applications of said amps - and everything else for that matter. So, I take issue with the statement, even with the "often" qualifier, which implies that "usually" tube amps are NG. (saying this while using a solid state amp most of the time myself, ok?)
I think that the question was "compensation". To me that is unclear - frequency (amplitude) or impedance or both? Or some other?
Obviously you do not need two xovers, although a case can be made for a "split" xover for HP sections...
The idea that solid state is automatically better, I think is false, and very dependent upon the precise and exact application. There are "good" and "bad" amps of all types. Also and more importantly, there are "good" and "bad" applications of said amps - and everything else for that matter. So, I take issue with the statement, even with the "often" qualifier, which implies that "usually" tube amps are NG. (saying this while using a solid state amp most of the time myself, ok?)
I think that the question was "compensation". To me that is unclear - frequency (amplitude) or impedance or both? Or some other?
Obviously you do not need two xovers, although a case can be made for a "split" xover for HP sections...
Hanging a Zobel across a tweeter that is directly driven by an amplifier is of no benefit.
Zobels can be though of as impedance flateners with no impact on response, but of course they do impact response if there is significant network driving them, as they are changing the termination impedance of the previous stage. In the case of a bi/triamped system since the source impedance and cable impedances are typically low then we wouldn't expect any response or sound change with adding a Zobel.
Most amps are happy to see some inductance in the load they are driving and no one has proved that driving a dead flat load impedance is of any benefit to a well designed amplifier.
David
Most tube amps have an appreciable output impedance, and so would benefit from a flat impedance curve in the load.
Source impedance, which leads to FR errors driving nonresistive loudspeakers.
When dealing with a high source impedance amp, a distinction without a difference.
A good answer is to use a modern amp, and leave the overpriced lightbulbs for others.
Hi,
Some serious nonsense in this thread. For any tweeter
driven directly by a half decent amplifier * any parallel
network of the RLC or RC variety is very pointless.
rgds, sreten.
* Unusual high output impedance does change things.
Even so being active its relatively easy to compensate
for any changes in the active x/o slopes and EQ.
Some serious nonsense in this thread. For any tweeter
driven directly by a half decent amplifier * any parallel
network of the RLC or RC variety is very pointless.
rgds, sreten.
* Unusual high output impedance does change things.
Even so being active its relatively easy to compensate
for any changes in the active x/o slopes and EQ.
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Please define what you mean by "high source impedance"?
Are you ok with a 1:1 ratio match? Or is that no good? Why?
Is a 0.00001:1 match always the "best" in terms of how it sounds and how it measures?
What was done in the amp to get the output Z low - how low, but what means? Are there any consequences?
This is provocative stuff that doesn't accurately reflect reality.
Again, for the record, I use my Symphony No.1 solid state amp most of the time.
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