When comparing two drivers with different impedances, 4 vs 8 ohm, i almost always favour the low imp driver, they sound much faster and agile and with less boomy bass
Is this real sonic differencies or just a classic testing protocol failure?
Is this real sonic differencies or just a classic testing protocol failure?
Well, a 4 ohm driver has always less mass than it's 8 ohm sibling - could make a difference. The amp used for this evaluation might behave differently - hence, a perceived difference.
So hard, so hard...
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So hard, so hard...
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Let's try to compare apples to apples. If you compare the same model of driver (woofer), but in 4-ohm and 8-ohm version, in general the 4-ohm driver has lower Qts parameter, so yes - less boomy bass.
Edit: difference between 4 and 8 ohm version is the voice coil only, everything else is identical: cone mass, etc.
Edit: difference between 4 and 8 ohm version is the voice coil only, everything else is identical: cone mass, etc.
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Indeed, it seems so - how very strange. Why not used the same strand wire for the coil? Have to admit I shot that one form the hip. Mustn't do that... Sorry.
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Distorted crap.
@TNT
Probably to maintain the same power handling and the number of turns of the voice coil, but I am not sure about the latter.
Just as i suspected, it is near impossible to test anything, there is always some flaws, better to do nothing
I have never had the opportunity to listen to the same driver in both the 4 ohm and 8 ohm version... So my comments are purely speculative...
The 4 ohm version of a woofer usually has a few more db of voltage sensitivity, so for a given "volume knob" setting, the 4 ohm version will play a little louder... most of the time, our brains percieve louder as better. So perhaps repeat the test and carefully control for SPL... ?
If your enclosure is a sealed box, than you can probably swap a 4 ohm and an 8 ohm version of the same woofer and still have a fair comparison. With a vented box, that probably is not true. You would need one box optimized for the 4 ohm, and another box optimized for the 8 ohm.
Here is a speculation: Are not some forms of distortion proportional to diaphram displacement, while other forms are proportional to current through the voice coil? If this is true, than the 4 ohm version should have (in theory) higher distortion than the 8 ohm version due to the greater current.
It is an interesting observation
The 4 ohm version of a woofer usually has a few more db of voltage sensitivity, so for a given "volume knob" setting, the 4 ohm version will play a little louder... most of the time, our brains percieve louder as better. So perhaps repeat the test and carefully control for SPL... ?
If your enclosure is a sealed box, than you can probably swap a 4 ohm and an 8 ohm version of the same woofer and still have a fair comparison. With a vented box, that probably is not true. You would need one box optimized for the 4 ohm, and another box optimized for the 8 ohm.
Here is a speculation: Are not some forms of distortion proportional to diaphram displacement, while other forms are proportional to current through the voice coil? If this is true, than the 4 ohm version should have (in theory) higher distortion than the 8 ohm version due to the greater current.
It is an interesting observation
"When comparing two drivers with different impedances, 4 vs 8 ohm, i almost always favour the low imp driver, they sound much faster and agile and with less boomy bass"
Not necessarily, the coil might be thicker to allow greater current.
"Let's try to compare apples to apples. If you compare the same model of driver (woofer), but in 4-ohm and 8-ohm version, in general the 4-ohm driver has lower Qts parameter, so yes - less boomy bass.
Edit: difference between 4 and 8 ohm version is the voice coil only, everything else is identical: cone mass, etc. "
The "same model" may in fact be slightly different in some aspects for optimisation purposes.
"Just the other way around. But more significant is the stronger motor of a 4 Ohm driver because of more current flowing through the voice coil. "
"What is the sound of an amp running out of Voltage? Running out of current? "
Both, on sine, produce clipping, but produce a different waveform, the former produces a clip of the peaks, the latter a sloping decline from the peak not following the wave form.
The "strength of the motor" is given by BL, gap flux X the length of the coil.
Not necessarily, the coil might be thicker to allow greater current.
"Let's try to compare apples to apples. If you compare the same model of driver (woofer), but in 4-ohm and 8-ohm version, in general the 4-ohm driver has lower Qts parameter, so yes - less boomy bass.
Edit: difference between 4 and 8 ohm version is the voice coil only, everything else is identical: cone mass, etc. "
The "same model" may in fact be slightly different in some aspects for optimisation purposes.
"Just the other way around. But more significant is the stronger motor of a 4 Ohm driver because of more current flowing through the voice coil. "
"What is the sound of an amp running out of Voltage? Running out of current? "
Both, on sine, produce clipping, but produce a different waveform, the former produces a clip of the peaks, the latter a sloping decline from the peak not following the wave form.
The "strength of the motor" is given by BL, gap flux X the length of the coil.
Okay, maybe I misspelled.
A lower impedance drive generates more moving forces if everything else is equal except the impedance. The more moving force comes from the flowing of more current through the voice coil.
A motor strength alone is nothing without electrical current.
Its really hard to generalize this, the 8 Ohm will have more turns of thinner wire, which partly makes up for the halved motor current.
The mass of the two coils is going to be similar, the gap is filled with copper either way.
The mass of the two coils is going to be similar, the gap is filled with copper either way.
I fully second davidsrsb's arguments. There's no reason why a 8 ohm VC should be heavier or lighter than a 4 ohms one, and why the »motor strenghts« should differ.
Best regards!
Best regards!
In building ribbons it often seems the low resistance designs sound somehow better than the high resistance designs
And this is basically at the same mass ( same foil thickness just more smaller runs of it in higher resistance designs)
No real scientific eval of this, it just seems that way often when playing around with making different designs.
Also not saying the lower resistance designs are actually technically better, they just seem to have some sort of desirable sonic quality.
It may be interesting to note that possibly the favorite ( by many) Apogee ribbon were their very low resistance designs. Amp eaters but......
Im not at all sure this has any connection to what Op is talking about
And this is basically at the same mass ( same foil thickness just more smaller runs of it in higher resistance designs)
No real scientific eval of this, it just seems that way often when playing around with making different designs.
Also not saying the lower resistance designs are actually technically better, they just seem to have some sort of desirable sonic quality.
It may be interesting to note that possibly the favorite ( by many) Apogee ribbon were their very low resistance designs. Amp eaters but......
Im not at all sure this has any connection to what Op is talking about
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Is this true IF we are restricted to a given magnet architecture and pk pk linearity?
These arguments are backed for instance by the TSP's of JBL transducers that are available in different impedance values. The only parameters that differ are RE, LE and BL. All others, especially efficiency, are identical.
Bets regards!
Bets regards!