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[Al Rettich]

Have a pair of original MTL 4’s. 800w into 4ohms.  Thought I had a pair of amps that put out 800w into 4 ohms, but I don’t.  What I do have is a pair of Crown XTi 6002’s.  2100w into 4 ohms. I know I can turn down the volume, but trying to remember the voltage so I can set the limiter at 800w.  Can someone help a guy out?

[Scott Holtzman]

Have a pair of original MTL 4’s. 800w into 4ohms.  Thought I had a pair of amps that put out 800w into 4 ohms, but I don’t.  What I do have is a pair of Crown XTi 6002’s.  2100w into 4 ohms. I know I can turn down the volume, but trying to remember the voltage so I can set the limiter at 800w.  Can someone help a guy out?

The simple answer is 56.6 voltage=current*resistance


It's ohms law.  Learn the formula and you can always answer these questions.


The problem with the simple answer is it will not get the most out of your speaker.  You have to consider the crest factor of your music and the speakers ability to handle transients.  Then you can set a voltage limiter.  Do the XTi's have a voltage limiter?


Much of this comes from having experience and blowing a few drivers along the way.  A good education isn't cheap.


Are you interested in 4 fully loaded and refurbed subs to go with them?

[Mike Caldwell]

While your programming the amp set a high pass at 40hz Butterworth at least 24db for those.
The 800 watt rating was RMS so EV called it a 1600 watt program rating.

You could bump it up to 1200 watts and be safe / 70 volts.

[Art Welter]

While your programming the amp set a high pass at 40hz Butterworth at least 24db for those.
The 800 watt rating was RMS so EV called it a 1600 watt program rating.

You could bump it up to 1200 watts and be safe / 70 volts.

Mike,

The MTL4 is two "800 watt" four ohm loads, 1600 watts EIA RS426A, 6400 watts peak for for 10 milliseconds.
Fb (box tuning) is 37Hz, the minimum impedance at Fb is 3.45 ohms, 52.5 volts for 800 watts.

A BW24dB at 35 Hz would be safe, but over 52.5 volts for long term limiting could char those drivers.
The EV test signal using -3dB points at 100Hz and 1200Hz allowed 105 volts peak (3200watts)

45-50 volts RMS long term (a couple seconds..) & 70volts (1420 watts) as a peak limit should be a good start to keeping the drivers intact, if the horizontal pair have not already sagged too far ;^).

Art

[Ivan Beaver]

Have a pair of original MTL 4’s. 800w into 4ohms.  Thought I had a pair of amps that put out 800w into 4 ohms, but I don’t.  What I do have is a pair of Crown XTi 6002’s.  2100w into 4 ohms. I know I can turn down the volume, but trying to remember the voltage so I can set the limiter at 800w.  Can someone help a guy out?

This is another audio myth.

"Turning down the gain reduces the power output of the amp".  WRONG

Unless you exceed the voltage rails of the input stage, you can turn the amp down to "1" and it will still be able to deliver full power to the loudspeaker.  It will just take a larger input signal to do so.

Limiters can be tricky to set up, depending on how many and what type you have to work with.

They are also like air bags in a car.  they can help protect against certain things, but driving it over a cliff don't expect them to protect you.  Responsible operation is the best protection.

If you don't have responsible operation, then BE SURE to set the limiters LOWER than what might be "normal".

For a single stage limiter, I suggest setting it between 1/4 continuous (not program) power (half voltage) or at the continuous rating.

It depends on the speed of the attack. If it is "automatic", then it is usually tied to the high pass filter time.

[Scott Holtzman]

This is another audio myth.

"Turning down the gain reduces the power output of the amp".  WRONG

Unless you exceed the voltage rails of the input stage, you can turn the amp down to "1" and it will still be able to deliver full power to the loudspeaker.  It will just take a larger input signal to do so.

Limiters can be tricky to set up, depending on how many and what type you have to work with.

They are also like air bags in a car.  they can help protect against certain things, but driving it over a cliff don't expect them to protect you.  Responsible operation is the best protection.

If you don't have responsible operation, then BE SURE to set the limiters LOWER than what might be "normal".

For a single stage limiter, I suggest setting it between 1/4 continuous (not program) power (half voltage) or at the continuous rating.

It depends on the speed of the attack. If it is "automatic", then it is usually tied to the high pass filter time.

800 is going to limit your peaks and constrain your output.  I wish I knew the tech side to tell you exactly what to do.  My gut tells me unless you are crazy that amp is sized right fir the MTL's.  Let is breath.

[Tim McCulloch]

800 is going to limit your peaks and constrain your output.  I wish I knew the tech side to tell you exactly what to do.  My gut tells me unless you are crazy that amp is sized right fir the MTL's.  Let is breath.

That's the idea, Scott.  Have you owned or maintained the MTL-4?  They're stuffed with 4-18" woofers that have a continuous heat dissipation of about 200W each and an xMax of about 8-10mm.

[Scott Holtzman]

That's the idea, Scott.  Have you owned or maintained the MTL-4?  They're stuffed with 4-18" woofers that have a continuous heat dissipation of about 200W each and an xMax of about 8-10mm.

Yes we have two of each I would love to get out of the warehouse.  Originally had two top boxes and four subs a side but the six subs flew the coup.  I believe the other two tops are somewhere in the warehouse.

[Tim Hite]

The simple answer is 56.6 voltage=current*resistance


It's ohms law.  Learn the formula and you can always answer these questions.


The problem with the simple answer is it will not get the most out of your speaker.  You have to consider the crest factor of your music and the speakers ability to handle transients.  Then you can set a voltage limiter.  Do the XTi's have a voltage limiter?


Much of this comes from having experience and blowing a few drivers along the way.  A good education isn't cheap.


Are you interested in 4 fully loaded and refurbed subs to go with them?

Where are you getting the current figure here and what it it? 7.075A is what I'm showing working backwards, but where is that coming from?

[Chris Hindle]

That's the idea, Scott.  Have you owned or maintained the MTL-4?  They're stuffed with 4-18" woofers that have a continuous heat dissipation of about 200W each and an xMax of about 8-10mm.

Back in the day, I seem to remember using QSC EX-4000. Driven in stereo to each box. 2 x 4 ohm loads. Good solid sound, and never tore up a driver. At the time, "we" had 8 blocks (8 tops, 8 bottoms). Another local shop had 8 more so we could each double up when needed.
Chris.

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