Bl/Mms = Nonsense

[haraldo]

Came across this paper, suggesting that the most important single factor for "subwoofer speed" is the lack of self inductance, never heard anything like this before...... but seem to make sense...... any opinions on these things?

http://web.archive.org/web/20010810141852/lambdacoustics.com/library/whitepapers/bl_mms.htm

So subwoofer speed is just pure plain nonsense, it's just a need for sub's with minimal self inductance and ability to play high frequencies?

 

[highfigh]

Came across this paper, suggesting that the most important single factor for "subwoofer speed" is the lack of self inductance, never heard anything like this before...... but seem to make sense...... any opinions on these things?

http://web.archive.org/web/20010810141852/lambdacoustics.com/library/whitepapers/bl_mms.htm

So subwoofer speed is just pure plain nonsense, it's just a need for sub's with minimal self inductance and ability to play high frequencies?

Sub speed is not pure nonsense but I think their point is that it's not possible to choose a woofer without considering the self inductance. Personally, since the Le is one of the parameters used to determine the proper cab and crossover, the paper is kind of pointless, other than raising a point that should be fairly obvious when looking at a full set of parameters.

The paper mentions "The acceleration of a driver is described by;

Force/Mass

Many people and even other speaker companies confuse this and say the force is equal to the Bl parameter of a speaker. After all it is called the "Force Factor" right?"

All this really does is call out people/companies who use Force factor as the term for the actual force from the signal/voice coil/flux interface.

A driver with high self-inductance and high mass can't react as quickly as a lower inductance/mass driver but a magnet with higher flux can counter this. Also, if the woofer has these "problems", it's still usable, just not for a wide bandwidth and this is all part of good driver selection.

IMO.

 

[mtrycrafts]

Came across this paper, suggesting that the most important single factor for "subwoofer speed" is the lack of self inductance, never heard anything like this before...... but seem to make sense...... any opinions on these things?

http://web.archive.org/web/20010810141852/lambdacoustics.com/library/whitepapers/bl_mms.htm

So subwoofer speed is just pure plain nonsense, it's just a need for sub's with minimal self inductance and ability to play high frequencies?

This link is embedded in one of the 'sticky' above:

http://www.audiopulse.com/know-how/subwoofer-driver-guide/myths-about-subwoofers/

check number 3 about speed and the whole page too

 

[haraldo]

This link is embedded in one of the 'sticky' above:

http://www.audiopulse.com/know-how/subwoofer-driver-guide/myths-about-subwoofers/

check number 3 about speed and the whole page too

Yes, this is a very very good read, I remember this from before too, but they donæt talk so much about self-inductance....

 

[mtrycrafts]

Yes, this is a very very good read, I remember this from before too, but they donæt talk so much about self-inductance....

Maybe it is not as important as claimed?

 

[WmAx]

Inductance has no direct relation to sound quality. It dictates the upper bandwidth limit. That is about it.

The fascination with inductance probably comes from the fact that often a driver with high inductance has a poorer motor design with high distortion/high non-linear distortion. But this is not always true, and as such, can not be used as a definitive indicator. You really must perform extensive distortion analysis of any given driver to know with certainty. Take for example the JL Audio W7 drivers and many of the TC Sounds/Audio Pulse drivers; most of these have relatively high inductance, yet are some of the finest sub woofer drivers in existence.

-Chris