Please Bust this myth: "Slow" speakers and "Slow" bass attack

[mambo4]

Form the general instruction forums, a discussion of playing ahead/behind the beat

because the attack of bass notes tend to have a longer delay -- from no sound to maximum sound -- than on other instruments. Also, some speakers react slower than other. If you are working with speakers that react slowly..[like in the 70's] then a bass player would have to play before the beat so that when the down beat finally occurs, the bass sound is has reached its maximum volume.

I'm sorry, but this sounds like hogwash to me, especially the "speakers reacting slowly" bit.

Similarly , I'm pretty sure the attack of a bass note happens at speeds where the difference is timbral, not rhythmic.

Can anybody with an audio engineering background comment?

Clarified question: Is there such thing as a speaker reacting so "slowly" that it forces the player to compensate by playing ahead of the beat?

 

[JimmyM]

No background, but it's the frequency response that makes you think a speaker is slow or fast and has zipola to do with the speed of its motor, which is instantaneous in all of them.

 

[David Jayne]

Here's my theory. Take a large speaker and attach a small motor to it, like in the 70's. It has to move a large mass of air (which has a surprising amount of mass). Now it MAY be that the small motor can't accelerate the cone+air mass as quickly as a larger motor, but that just means that it won't move as FAR as it might like before being told to reverse direction. Result? Lower volume. Less displacement, less noise. There may be some distortion also as a result of this and the smart folks will be along soon to explain it better (and probably shoot holes in my theory).

 

[Rick James]

No background, but it's the frequency response that makes you think a speaker is slow or fast and has zipola to do with the speed of its motor, which is instantaneous in all of them.

Some background, and you're right. People who use the terms fast and slow do so because they don't know the correct terms for whatever it is that their trying to describe. All motors react with the same speed, which isn't instantaneous, but since the speed of electrons in a voice coil is about 130,000 miles per second it might as well be.

 

[ArtechnikA]

All motors react with the same speed...

So you're saying they're exempt from F = mA ?

 

[chaosMK]

Maybe "Slow is in the fingers"

No idea how it all works but I have definitely used rigs that sound/feel faster or slower than others.

 

[CL400Peavey]

So you're saying they're exempt from F = mA ?

No. But when the reaction of the motor is based upon the speed of an electron, you dont have much moving mass. How effective that motor is, is another story.

That said, if two drivers are producing the same frequency, they are moving at the same speed.

 

[RoadRanger]

Cabs with an exaggerated low end then to "bloom" at higher volumes due to the fundamental or second harmonic feeding back. Sealed cabs with their natural low end roll off tend to not - hence the love for the "tightness" of the Ampeg 8x10 and similar cabs. I have a Peavey TVX 4x10 that blooms big-time. You either have to fight it with a HPF or "go with it" - great for Reggae .

 

[ArtechnikA]

That said, if two drivers are producing the same frequency, they are moving at the same speed.

If they're producing the same frequency at the same displacement, I agree they're moving at the same speed.
If one has larger excursion, its voice coil must be travelling faster at mid-cycle to maintain the same frequency - no ?
If it is covering a larger distance at the same rate, it must be moving faster to do it.

 

[David Jayne]

If they're producing the same frequency at the same displacement, I agree they're moving at the same speed.
If one has larger excursion, its voice coil must be travelling faster at mid-cycle to maintain the same frequency - no ?
If it is covering a larger distance at the same rate, it must be moving faster to do it.

Just like a short vs. long stroke engine. Short stroke engines have lower piston speeds at a given RPM.

 

[JdoubleH]

It's all in your head... That is after the room has its say. And by that I mean it's all perception in our heads that has more to do with room acoustics and frequency response than the electrical or mechanical properties of the speaker system. Any actual delay you perceive is in the room. Different cabs interact differently with a given room.

Could it make you struggle with the pocket? Sure, just like trying to hold a conversation on a phone with a long delay.

 

[CL400Peavey]

If they're producing the same frequency at the same displacement, I agree they're moving at the same speed.
If one has larger excursion, its voice coil must be travelling faster at mid-cycle to maintain the same frequency - no ?
If it is covering a larger distance at the same rate, it must be moving faster to do it.

If they are producing the same frequency, they are moving at the same rate. Displacement determines amplitude=volume

 

[ArtechnikA]

If they are producing the same frequency, they are moving at the same rate. Displacement determines amplitude=volume

Maybe we're using different referents for 'they'...

I'm talking about the voice coil/diaphragm.
If it's covering twice the distance in the same time, how is it not moving faster at mid-cycle ?
(I agree they're both moving at 0 at the extrema...)

 

[Bass_Pounder]

If they're producing the same frequency at the same displacement, I agree they're moving at the same speed.
If one has larger excursion, its voice coil must be travelling faster at mid-cycle to maintain the same frequency - no ?
If it is covering a larger distance at the same rate, it must be moving faster to do it.

Look at it this way...........

If you ran a mixed rig (1X18 + 4X10) do you really believe it would sound like you were playing with a delay ?

 

[David Jayne]

If they are producing the same frequency, they are moving at the same rate. Displacement determines amplitude=volume

But if one is displacing more than another by moving further, it must be moving faster mid stroke as Art said. Has to be.

 

[Passinwind]

Form the general instruction forums, a discussion of playing ahead/behind the beat


I'm sorry, but this sounds like hogwash to me, especially the "speakers reacting slowly" bit.

Similarly , I'm pretty sure the attack of a bass note happens at speeds where the difference is timbral, not rhythmic.

Can anybody with an audio engineering background comment?

Try reading the first few pages Invalid Link Removed. It is actually extraordinarily complicated, IMHO.

 

[CL400Peavey]

Maybe we're using different referents for 'they'...

I'm talking about the voice coil/diaphragm.
If it's covering twice the distance in the same time, how is it not moving faster at mid-cycle ?
(I agree they're both moving at 0 at the extrema...)

But if one is displacing more than another by moving further, it must be moving faster mid stroke as Art said. Has to be.

Yes, one cone may have a larger instantaneous velocity than another. That isnt how you measure the pitch of the note though.

 

[Coolhandjjl]

There's some confusion of terms and technology going on. The harmonic can often be louder than the fundamental, so it is logical to assume there is a delay in the biggest heft of the note coming through. Somewhere floating around here there is a waterfall graph that shows exactly that.

 

[David Jayne]

Yes, one cone may have a larger instantaneous velocity than another. That isnt how you measure the pitch of the note though.

Yes, of course.

 

[dincz]

Yes but that changing balance of harmonics after the initial attack is a characteristic of a vibrating string rather than the speaker.