"Fast Bass"  We all know it when we hear it.  And we know "Slow Bass" when we hear it too. Those words get thrown around a lot, but what do they mean in engineering terms? It's simple, really. Does the low frequency system's acoustic output closely track the input signal or does it do something else?  (It actually has nothing to do with speed; the woofers are not going faster, it has to do with....well....fidelity, accuracy.  But, anyway, Speed, Fast and Slow are good words so let's use them.) Speed means that when you put this in:
There are numerous reasons a system does not track the signal and, instead, does something else, is Slow.  And the #1 biggie is the deliberate choice by the designer: to trade Speed for an equally desirable trait: low frequency extension.  With passive systems you're stuck with that choice. You go with a vented alignment to get low bass and, in the process, you accept the ringing that comes along with it.  Or maybe you add mass to the woofer cone to get it to go low and accept that it takes a while to get going and while to stop. There are plenty of other strategies but each one pays for bass extension with Speed. I know. I made those choices. But now we're free from that.  Now we get 'em both! In our lab we align our systems for optimal Speed by looking directly at signal tracking and nothing else. Then we apply DSP equalization to ‘buy back’ the low frequencies without hurting the Speed.  It's so simple it's hard to believe. You know what? NONE of the conventional guys want to hear this stuff……but I'm having WAY TOO MUCH FUN. Dump your conventional gear while you can.......
You get this out:
Not this. This is Slow:
DESIGNERS’ BENCH Issue #5 - FAST BASS
Table of Contents
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DESIGNERS’ BENCH Issue #5 - FAST BASS
Table of Contents
"Fast Bass"  We all know it when we hear it.  And we know "Slow Bass" when we hear it too. Those words get thrown around a lot, but what do they mean in engineering terms? It's simple, really. Does the low frequency system's acoustic output closely track the input signal or does it do something else?  (It actually has nothing to do with speed; the woofers are not going faster, it has to do with....well....fidelity, accuracy.  But, anyway, Speed, Fast and Slow are good words so let's use them.) Speed means that when you put this in:
You get this out:
Not this. This is Slow:
There are numerous reasons a system does not track the signal and, instead, does something else, is Slow.  And the #1 biggie is the deliberate choice by the designer: to trade Speed for an equally desirable trait: low frequency extension.  With passive systems you're stuck with that choice. You go with a vented alignment to get low bass and, in the process, you accept the ringing that comes along with it.  Or maybe you add mass to the woofer cone to get it to go low and accept that it takes a while to get going and while to stop. There are plenty of other strategies but each one pays for bass extension with Speed. I know. I made those choices. But now we're free from that.  Now we get 'em both! In our lab we align our systems for optimal Speed by looking directly at signal tracking and nothing else. Then we apply DSP equalization to ‘buy back’ the low frequencies without hurting the Speed.  It's so simple it's hard to believe. You know what? NONE of the conventional guys want to hear this stuff……but I'm having WAY TOO MUCH FUN. Dump your conventional gear while you can.......