Hi,
I am lost in the uderstanding of group delay and also on how to choose the inductance characteritics of a bass driver.
I believe to know a coil for a low pass is adding a lot more of inductance that the driver has itself at those low frequencies. How much is it important in the choice of the bass driver please ?
What about a 8" having a Le of 0.2 uH like modern drivers with low efficienty and trade offs with older design with maybe 0.5 to 1 uH ?
My understanding is the lowest inductance gives the best group delay or am I mixing the concepts, i.e. missunderstanding the thing ?
I especially asking myself what Le range should be preferabily chosen when we need to pick up a mid bass drivers, these 6" to 8" drivers that are asked to make 50 hz as 800 hz ??? Is there a threshold where we should don't care anymore cause too much difficult to manage below a limit ? For instance 100 hz or else at seing for instance some waerfall in the bass areas ?!
How much should I care of the inductance in the datasheet, then in the coil filter for a first order low pass, please ?
Sorry if I am mixing up the thing too much btw...
Many thanks if you could beginn to enlight me...or give me simple path to follow fon howw to consider the Le of a bass driver.
I am lost in the uderstanding of group delay and also on how to choose the inductance characteritics of a bass driver.
I believe to know a coil for a low pass is adding a lot more of inductance that the driver has itself at those low frequencies. How much is it important in the choice of the bass driver please ?
What about a 8" having a Le of 0.2 uH like modern drivers with low efficienty and trade offs with older design with maybe 0.5 to 1 uH ?
My understanding is the lowest inductance gives the best group delay or am I mixing the concepts, i.e. missunderstanding the thing ?
I especially asking myself what Le range should be preferabily chosen when we need to pick up a mid bass drivers, these 6" to 8" drivers that are asked to make 50 hz as 800 hz ??? Is there a threshold where we should don't care anymore cause too much difficult to manage below a limit ? For instance 100 hz or else at seing for instance some waerfall in the bass areas ?!
How much should I care of the inductance in the datasheet, then in the coil filter for a first order low pass, please ?
Sorry if I am mixing up the thing too much btw...
Many thanks if you could beginn to enlight me...or give me simple path to follow fon howw to consider the Le of a bass driver.
Three points :
_voicecoil inductance can be considered as a serie inductance, so, it (somewhat) (inter-)acts as low pass as if it were from passive crossover.
_voicecoil inductance most often varies (a lot) with excursion (depending of motor design), so others things equals, higher inductance drivers are most prone to distortion. Inductance comes (somewhat again) from bigger voicecoil, but can be a lot nulled by aluminium and copper cap and rings in driver's motor.
_inductance change with resistance (somewhat^^). A fixed inductance only compare right to a fixed Re. There's for given as 8 ohm driver, drivers from Re=around 5, to 8 ohm...
=> low inductance can mean either smaller voicecoil, or better built motor if same size and height voicecoil. So the question is, will you use the driver in it linear range, well below Xmax, and so, it doesn't matter, or will you abuse it, and so you need it to keep linear even at high excursion ?
Klippel papers are really interesting regarding those considerations.
_voicecoil inductance can be considered as a serie inductance, so, it (somewhat) (inter-)acts as low pass as if it were from passive crossover.
_voicecoil inductance most often varies (a lot) with excursion (depending of motor design), so others things equals, higher inductance drivers are most prone to distortion. Inductance comes (somewhat again) from bigger voicecoil, but can be a lot nulled by aluminium and copper cap and rings in driver's motor.
_inductance change with resistance (somewhat^^). A fixed inductance only compare right to a fixed Re. There's for given as 8 ohm driver, drivers from Re=around 5, to 8 ohm...
=> low inductance can mean either smaller voicecoil, or better built motor if same size and height voicecoil. So the question is, will you use the driver in it linear range, well below Xmax, and so, it doesn't matter, or will you abuse it, and so you need it to keep linear even at high excursion ?
Klippel papers are really interesting regarding those considerations.
While what was written is actually true it doesn't answer the OP's question or it only scratches the Surface of it.
Lvc does indeed form a lowpass pole together with the DC resistance of the driver. This does indeed give a grpup delay. But to this one some more will be added in the form of all the mechanical lowpass properties of the driver and the electrical crossover lowpass. So it Plays a minor role in terms of added group delay if a driver is used as intended.
The biggest group delay distortion contributions in absolute terms arise at the lower end of a driver's bandwidth.
Regards
Charles
Lvc does indeed form a lowpass pole together with the DC resistance of the driver. This does indeed give a grpup delay. But to this one some more will be added in the form of all the mechanical lowpass properties of the driver and the electrical crossover lowpass. So it Plays a minor role in terms of added group delay if a driver is used as intended.
The biggest group delay distortion contributions in absolute terms arise at the lower end of a driver's bandwidth.
Regards
Charles
Of course, if master Charles comes and answer, it's clear; this is something else than my spaghetti learned stuff regurgitation in random english ^^
Ahaha Papasteak, I like your joke ! Btw, had a look at good folkds that written some things on the phase and group delay but stangely not sure there were anything about such siple asking about drivers'Le !
Thanks guys,
I was looking at two or three Audax drivers which are between 0.5 and more than 1 : two are 8" with different Le : 0.5 circa and more than 1 uH for the other : i that order HM210Z0 and maybe a more recent design HM210Z12
Same occurs with some different 6" : HM170Z0 & HM170Z18
They are in the same Prestige quality line from Audax but the number after Z is certainly about the mark, so higher the later I assume ! I just noticed that higher inductance seemed to give a different -F3 and Vas but not sure there are any corelation here ! Just asked myself if I could have as much transcient (impulse response) with both inductance if the amp is strong enough (knowing now inductance in the ow end + the coil give anyway high inductance number... well active low pass there without coil certainly a big plus... but I am a passive guy as it's about a learning 3 way Proto...
🙂
Thanks guys,
I was looking at two or three Audax drivers which are between 0.5 and more than 1 : two are 8" with different Le : 0.5 circa and more than 1 uH for the other : i that order HM210Z0 and maybe a more recent design HM210Z12
Same occurs with some different 6" : HM170Z0 & HM170Z18
They are in the same Prestige quality line from Audax but the number after Z is certainly about the mark, so higher the later I assume ! I just noticed that higher inductance seemed to give a different -F3 and Vas but not sure there are any corelation here ! Just asked myself if I could have as much transcient (impulse response) with both inductance if the amp is strong enough (knowing now inductance in the ow end + the coil give anyway high inductance number... well active low pass there without coil certainly a big plus... but I am a passive guy as it's about a learning 3 way Proto...
🙂Based on above blabla, and looking at datasheet showing same size same resistance voicecoils, i would suspect better motor design in Z0 versions. Something like T-pole VS straight pole piece. If there were demodulation ring or copper cap, this would have probably been over-promoted in datasheets. Just my 2 centimes...
Both are from the Prestige, aka HM serie... normalement the same motor (more DS than 2cv)... the Z12 is almost three times the inductance of the Z0... for very near T&S for the rest of !
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At iso use, where do you put the step frequency cursor please and Le number between the : "we don't care" and "have a close look", please ? It's about knowing how much I should care about that in that difficult bass and mid behavior in a one driver to make them both - say bass + mid until around 700/800 hz- .
If talking about distorsion I'm not too much worried below 100 hz for instance looking at ears sensivity and room mode make anyway things too much complicate for me to understand... or at least to sort out in importance order for a design. I would simply tell to myself, below Schrowder frequency you listen more the walls than the direct sound of the loudspeakers.
But how much needed for the transcient in the say circa 80/100 hz to 200/250 hz where there are a lot of punch behavior and acurate transcient + good phase behavior of the harmonics needed in a context of a standalone driver that makes everythings : the famous 6" to 8" of most of the loudspeakers that are fireing from the low end to ...low mid/treble if 3ways/2ways.
Ok choose the lowest Le then your cabinet should be often bigger (if I'm following acuratly which I suspect not to be 😱) or no so important also in the mid band - say upon 100 he in my language cause where most of the human voices beginn... while being in the middle of the widiw frequency where punch chest/slam also occurs ?! 😕
Of a simplier way to ask because I surely miss most of the explains : Do I care for the same close speaker here (40/50 hz to 700/800 hz) between a Le= 0.2 or 0.5 or 1.2 uH ? Or keep it cool, choose what spl and Vas you like most vis à vis of the bafle step and box size ?
If talking about distorsion I'm not too much worried below 100 hz for instance looking at ears sensivity and room mode make anyway things too much complicate for me to understand... or at least to sort out in importance order for a design. I would simply tell to myself, below Schrowder frequency you listen more the walls than the direct sound of the loudspeakers.
But how much needed for the transcient in the say circa 80/100 hz to 200/250 hz where there are a lot of punch behavior and acurate transcient + good phase behavior of the harmonics needed in a context of a standalone driver that makes everythings : the famous 6" to 8" of most of the loudspeakers that are fireing from the low end to ...low mid/treble if 3ways/2ways.
Ok choose the lowest Le then your cabinet should be often bigger (if I'm following acuratly which I suspect not to be 😱) or no so important also in the mid band - say upon 100 he in my language cause where most of the human voices beginn... while being in the middle of the widiw frequency where punch chest/slam also occurs ?! 😕
Of a simplier way to ask because I surely miss most of the explains : Do I care for the same close speaker here (40/50 hz to 700/800 hz) between a Le= 0.2 or 0.5 or 1.2 uH ? Or keep it cool, choose what spl and Vas you like most vis à vis of the bafle step and box size ?
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