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[Yosi Melamed]

Part of the reason I ask, is that the stated response (-3dB) is 55Hz, while on the response chart the -3dB point is below 40Hz.

Why would they cheat themselves on a spec like that?  Maybe either the graph or the spec is wrong.  It happens.

Dear Ivan,
I sent an eMail to CV about that, maybe they can shed some light on the subject.
I also went through the charts of other ProStax speakers and found that the chart of the PS-12 to be identical to the chart on the PS-152 and it also fits that model's specs for the highs as well, so maybe it's just a simple mixup only with the charts.

In the mean time what do you say we consider the 55Hz -3dB as the correct data?

[Yosi Melamed]

Connect a tone generator and run a moderately low signal thru. Sweep downwards from 100hz till you see the cone motion get to a minimum (it helps if you paint a small white dot on the cone) that frequency will be fB (frequency of the box) then set your high pass to that point. Woofers tend to "unload" below fB in ported boxes so excursion and distortion increase quickly. If you don't have a tone generator the you can download free versions off the net and run it thru your computer:)


I didn't hear from CV back yet but what do you think about the method above to measure the frequency for the HP filter?

[Ivan Beaver]

Dear Ivan,
I sent an eMail to CV about that, maybe they can shed some light on the subject.
I also went through the charts of other ProStax speakers and found that the chart of the PS-12 to be identical to the chart on the PS-152 and it also fits that model's specs for the highs as well, so maybe it's just a simple mixup only with the charts.

In the mean time what do you say we consider the 55Hz -3dB as the correct data?

I would start with a Butterworth 24dB slope at 50Hz.

[Yosi Melamed]

I would start with a Butterworth 24dB slope at 50Hz.

Thank you, will start from there.

When I use a limiter, how doe's it effect the need for amp headroom?
If I understand correctly, speakers have allot of headroom for transient peaks, if I'm using a limiter, wouldn't it essentially get rid of those peaks, ending up with a system that has less volume or less kick?

[Ivan Beaver]

Thank you, will start from there.

When I use a limiter, how doe's it effect the need for amp headroom?
If I understand correctly, speakers have allot of headroom for transient peaks, if I'm using a limiter, wouldn't it essentially get rid of those peaks, ending up with a system that has less volume or less kick?

As with many things in the business-limiters are misunderstood and misapplied and expected to do things they shouldn't.

Basically there are 2 things that kill a loudspeaker-excessive temp (power over time-NOT just power alone) and overexcursion.

You can easily drive a loudspeaker really hard with even 1/2 cycle and destroy it-if it goes past its mechanical limits.

A "proper" limiter is fairly complicated-has many parameters and is not easily setup with a good bit of data.  You really need a fast limiter (to help control the mechanical limits of the loudspeaker and to help keep the amps out of clipping)-a slow attack (to help control the thermal heating) and a level and freq dependant limiter (to help control the excursion).

And some people would argue you need more.  But how many people have the skill/knowledge/data to properly set them up? Certainly not the average user.  And with more control-comes more complexity and the possiblity of screwing it up.

A limiter is something you should never need-it is there "just in case".  If you are RELYING on the limiter (always into limiting for example) then you need a bigger rig-and are just asking for trouble.

Think of a limiter like the air bags in your car.  Do  you rely on the bags every time you stop?  Are you constantly running into things to stop?  Safe driving (like safe operation of your PA) is what keeps them from going off.

And don't expect the air bags to totally protect you.  They offer a "measure" of protection.  If you drive your car off a cliff-don't complain when the air bags didn't work properly and you are dead.

There is no magic-limiter setting-kick drum mic-subwoofer- etc etc.  It is a whole lot of "it depends" and variables.

OPERATING your system within normal limits is the key-NOT relying on some form of "protection".  Just like sex-but we won't go there.

[Tim McCulloch]

As with many things in the business-limiters are misunderstood and misapplied and expected to do things they shouldn't.

Basically there are 2 things that kill a loudspeaker-excessive temp (power over time-NOT just power alone) and overexcursion.

You can easily drive a loudspeaker really hard with even 1/2 cycle and destroy it-if it goes past its mechanical limits.

A "proper" limiter is fairly complicated-has many parameters and is not easily setup with a good bit of data.  You really need a fast limiter (to help control the mechanical limits of the loudspeaker and to help keep the amps out of clipping)-a slow attack (to help control the thermal heating) and a level and freq dependant limiter (to help control the excursion).

And some people would argue you need more.  But how many people have the skill/knowledge/data to properly set them up? Certainly not the average user.  And with more control-comes more complexity and the possiblity of screwing it up.

A limiter is something you should never need-it is there "just in case".  If you are RELYING on the limiter (always into limiting for example) then you need a bigger rig-and are just asking for trouble.

Think of a limiter like the air bags in your car.  Do  you rely on the bags every time you stop?  Are you constantly running into things to stop?  Safe driving (like safe operation of your PA) is what keeps them from going off.

And don't expect the air bags to totally protect you.  They offer a "measure" of protection.  If you drive your car off a cliff-don't complain when the air bags didn't work properly and you are dead.

There is no magic-limiter setting-kick drum mic-subwoofer- etc etc.  It is a whole lot of "it depends" and variables.

OPERATING your system within normal limits is the key-NOT relying on some form of "protection".  Just like sex-but we won't go there.

Brilliant.  Thank you, Ivan.

[Yosi Melamed]

As with many things in the business-limiters are misunderstood and misapplied and expected to do things they shouldn't.

Basically there are 2 things that kill a loudspeaker-excessive temp (power over time-NOT just power alone) and overexcursion.

You can easily drive a loudspeaker really hard with even 1/2 cycle and destroy it-if it goes past its mechanical limits.

A "proper" limiter is fairly complicated-has many parameters and is not easily setup with a good bit of data.  You really need a fast limiter (to help control the mechanical limits of the loudspeaker and to help keep the amps out of clipping)-a slow attack (to help control the thermal heating) and a level and freq dependant limiter (to help control the excursion).

And some people would argue you need more.  But how many people have the skill/knowledge/data to properly set them up? Certainly not the average user.  And with more control-comes more complexity and the possiblity of screwing it up.

A limiter is something you should never need-it is there "just in case".  If you are RELYING on the limiter (always into limiting for example) then you need a bigger rig-and are just asking for trouble.

Think of a limiter like the air bags in your car.  Do  you rely on the bags every time you stop?  Are you constantly running into things to stop?  Safe driving (like safe operation of your PA) is what keeps them from going off.

And don't expect the air bags to totally protect you.  They offer a "measure" of protection.  If you drive your car off a cliff-don't complain when the air bags didn't work properly and you are dead.

There is no magic-limiter setting-kick drum mic-subwoofer- etc etc.  It is a whole lot of "it depends" and variables.

OPERATING your system within normal limits is the key-NOT relying on some form of "protection".  Just like sex-but we won't go there.

Great writing
You made me laugh for a good few minutes, Thank you.

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