Anybody ever measured (not through the power and impedance rating, but actually measured) the current spikes that a driver might draw?
From this, one could determine what kind of cable makes sense to use for internal speaker wiring.
I am interested in full range driver in particular, specifically Eikona 2. But any input is welcome.
From this, one could determine what kind of cable makes sense to use for internal speaker wiring.
I am interested in full range driver in particular, specifically Eikona 2. But any input is welcome.
So, I thought I might share my findings first and see if other people's experience agree with mine.
I used my Fluke meter to measure max peak voltage and amperage sent to my Eikonas (free standing an a table).
I set the volume at a reasonable level, which sounds loud enough to me with certain material, and measured 8.38V max and 1.35A max with that material.
Under the hypothesis of a purely resistive load (to maximize power calculations and make sure I don't turn the volume up too much later on), that means 11.313 VA (W under such hypothesis).
Since the peak power is rated at 100W, there is still room for 100/11.313 = 8.84 times the power.
This means about 2.97 increase in A (or V), resulting in 2.97*1.35 = 4.01A peak
I increased the volume until voltage peak measured 15.7V, for an indication of how loud the Eikonas can sound getting somewhat near max power, but still very well within limits. 8.38*2.97 = 24.889V. so at 15.7 I was still 1.585 times under max voltage.
At this volume, the music was loud enough for me to not want to go higher.
A couple observations and questions:
1. Is a Fluke meter reliable enough to detect transient peaks for music?
2. It is very likely that the instantaneous power through the speakers is actually much lower than my worst case scenario calculations, and that the Eikonas could stand much higher peak voltage/amperage.
3. How much change and in what direction can I expect the amperage to go when the drivers will be installed in a cabinet (ballpark estimate).
4. In the unlikely event of listening to the drivers close to their max power peak rating, I'd like to use internal wiring capable of withstanding 10A peak current.
I was thinking about using litz wire (just to go overboard and not think about what I could do next to make things better). What equivalent gauge is required to handle 10A?
I used my Fluke meter to measure max peak voltage and amperage sent to my Eikonas (free standing an a table).
I set the volume at a reasonable level, which sounds loud enough to me with certain material, and measured 8.38V max and 1.35A max with that material.
Under the hypothesis of a purely resistive load (to maximize power calculations and make sure I don't turn the volume up too much later on), that means 11.313 VA (W under such hypothesis).
Since the peak power is rated at 100W, there is still room for 100/11.313 = 8.84 times the power.
This means about 2.97 increase in A (or V), resulting in 2.97*1.35 = 4.01A peak
I increased the volume until voltage peak measured 15.7V, for an indication of how loud the Eikonas can sound getting somewhat near max power, but still very well within limits. 8.38*2.97 = 24.889V. so at 15.7 I was still 1.585 times under max voltage.
At this volume, the music was loud enough for me to not want to go higher.
A couple observations and questions:
1. Is a Fluke meter reliable enough to detect transient peaks for music?
2. It is very likely that the instantaneous power through the speakers is actually much lower than my worst case scenario calculations, and that the Eikonas could stand much higher peak voltage/amperage.
3. How much change and in what direction can I expect the amperage to go when the drivers will be installed in a cabinet (ballpark estimate).
4. In the unlikely event of listening to the drivers close to their max power peak rating, I'd like to use internal wiring capable of withstanding 10A peak current.
I was thinking about using litz wire (just to go overboard and not think about what I could do next to make things better). What equivalent gauge is required to handle 10A?
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You'll get all kinds of opinions on this, but use whatever you want! The drivers have an RMS power rating of what, 50W? Good 14 awg wire should be sufficient.
What about the transient current? Is my estimate of 10 A accurate?
Can 14 AWG handle that without some non linear phenomenon coming into play and affect the cone's ability to track voltage signal?
Transient current depends on a lot of things, the most important factors being the inductance and resistance of the wire and voice coil of the speaker. Unless the wire is really bad, the voice coil inductance is always much higher than the wire inductance and same goes for the resistance.
Reducing the length of wire between the amp and the driver is one of the easiest things to do to minimize any negative effects the wire has.
You can do a basic approximation using V=L(di/dt), or a voltage across a field inductance will produce a change in current over a change in time.
Here's an article from Pass Labs that you might find interesting: https://www.passdiy.com/gallery/articles/speaker-cables
Reducing the length of wire between the amp and the driver is one of the easiest things to do to minimize any negative effects the wire has.
You can do a basic approximation using V=L(di/dt), or a voltage across a field inductance will produce a change in current over a change in time.
Here's an article from Pass Labs that you might find interesting: https://www.passdiy.com/gallery/articles/speaker-cables
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When looking at the voice coil and the wire used for it, one might be led to think that any AWG lower than 24 is probably OK to handle current spikes, unless the coil wire is made of some high current rated special sci-fi conductor.
All my calculation might be for naught, therefore.
However, I am interested to see if somebody has a different experience, based on measurements.
There is still the problem of wire resistance, for which lower AWG is always better.
I am inclined to think that 12 AWG litz wire is probably overkill, but a nice peace of mind touch, provided that inductance and capacitance are low.
Remember that I am talking about 2 ft max internal speaker wire.
So I know this is probably more of a theoretical exercise than anything else, but it is still good to check with other people that might have some angle on the subject that I am missing.
All my calculation might be for naught, therefore.
However, I am interested to see if somebody has a different experience, based on measurements.
There is still the problem of wire resistance, for which lower AWG is always better.
I am inclined to think that 12 AWG litz wire is probably overkill, but a nice peace of mind touch, provided that inductance and capacitance are low.
Remember that I am talking about 2 ft max internal speaker wire.
So I know this is probably more of a theoretical exercise than anything else, but it is still good to check with other people that might have some angle on the subject that I am missing.
You're over thinking this for just 2 ft of wire. Use the largest wire you can and focus on more important things like listening to music
Largest is fine for resistance, but it may be detrimental for inductance and capacitance.
I'm trying to find the happy medium, possibly based on people's actual experience and measurements.
I shall refrain from pontificating. For best results the properties of the cable can not be taken in isolation. I suggest you read this page sound.whsites.net/cable-z.htm. Litz wire has it's uses, particularly with high capacitance speakers such as electrostatics, but beware if can cause amplifier stability issues
I'm looking at things in isolation because physic's superposition principle says that I can, under condition that the system in use is linear.
I'm not trying to make up for bad amplifier design by using a cable that compensates for it.
I'm looking for the lowest R-L-C cable capable of handling 10A spikes, although this last requirement seems to be a problem only for very high AWG.
I'm not trying to make up for bad amplifier design by using a cable that compensates for it.
I'm looking for the lowest R-L-C cable capable of handling 10A spikes, although this last requirement seems to be a problem only for very high AWG.
there is a long report on this in one of the audio magazines.
It was linked from the Forum some years ago.
They found that low reactance speaker and medium reactance speaker and severe reactance speaker all drew peak transients on real music signals that exceeded 5 times the current demanded by the equivalent resistor impedance.
i.e. a 100W into 8ohms amplifier driving an 8r0 dummy load would see a peak demand of 5Apk.
But all three 8ohms test speakers showed a peak current demand of over 25Apk when driven with real music test signals.
There are a few papers/articles using contrived artificial signals and what effect these have on current demands of reactive speakers.
Many here cannot accept that a contrived signal can ever represent what happens in real life and therefore cannot accept the conclusions that reactive speakers can demand currents that exceed what the equivalent resistor would demand.
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Thank you. This is what I was looking for.
Now the next question is what kind of wire gauge might have a problem handling this kind of peak amperage?
Looking at coil wires and how thin they are, it looks like it must be a very high AWG. Low resistance requirements for cabling seems to point to the fact that at the 14 or lower AVG normally used, peak current handling is not an issue.
Would you agree with that?
The peak transient currents are by definition short term. The heating power in short term transients is low.
Heat is not the problem.
For near distortion free reproduction, the current that is allowed to flow should be as close to the demanded current as the amplifier system will allow.
My advice is to locate the amplifier VERY close to the speaker and to use VERY short cables to the speaker/crossover/driver.
Heat is not the problem.
For near distortion free reproduction, the current that is allowed to flow should be as close to the demanded current as the amplifier system will allow.
My advice is to locate the amplifier VERY close to the speaker and to use VERY short cables to the speaker/crossover/driver.
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Good advice, but I wonder how many amplifiers out there (of at least $100 value) don't account for stability in their output stage.
Then again, with the stuff that they sell out there, I might be surprised of the answer..
It seems like, though, as long as your wire is lower AWG than voice coil wire, you should be good. Amplifier's wiring is definitely lower AWG than coil wiring, so before incurring into amplifier's peak current issues (caused by the melting of the amplifier's wiring), your coil should be long gone.
I believe that the amplifier's internal electronics is actually what dictates the max current, but one can't do anything about that.
Low wire resistance requirement is probably much more stringent than peak current (or RMS), requiring much lower AWG than peak amperage.
Be realistic: a typical voice coil wire is around 0.20 mm diameter (AWG32), 16 (sixteen) meters long and has around 6 ohms resistance .... compared to that, a series 1 meter long wire, 1mm diameter (AWG18) and, as shown in the mentioned tests, varying between 0.25 and 0.45 ohms is IRRELEVANT .
Straight wire surrounded by air will have *a little* inductance , no doubt, but that is IRRELEVANT compared to 100 turns of fine wire wound around a 2" iron polepiece.
Not surprisingly, blind tests comparing U$500 a meter speaker wires to straightened iron wire coat hangers show no detectable difference.
Straight wire surrounded by air will have *a little* inductance , no doubt, but that is IRRELEVANT compared to 100 turns of fine wire wound around a 2" iron polepiece.
Not surprisingly, blind tests comparing U$500 a meter speaker wires to straightened iron wire coat hangers show no detectable difference.
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