so I got my first t30 running..

[Gregory East]

Is that 450W per cab you're meaning? What's the problem?

[Dan30]

Is that 450W per cab you're meaning? What's the problem?

well 50v is 141.5 watts, 159v is 449 watts and that's the watt rating of the driver. All i'm saying is I wish the driver was safe within that extra 100v range.

[CoronaOperator]

well 50v is 141.5 watts, 159v is 449 watts and that's the watt rating of the driver. All i'm saying is I wish the driver was safe within that extra 100v range.

I think your math might be a little off.

Watts = Volts squared/impedance
50*50/8 = 312.5 watts
159 * 159/8 = 3160 watts

[osse]

All things being equal the RMS power delivered in a signal is independent of the frequency. It is determined by the load and applied voltage.

Your crossover must be affecting things.

I did some testing today, and I get different voltage measurements depending which frequency sine I choose.

I'm using a DRPA+, isn't this a good unit for this purpose? I mean, with my peavey PV3800 amp the voltage swing is very unpredictable, it seem you can't "set and forget" the limiter as it depens on frequency... Everytime I accidently feed the 3012lf with more than 50 volts it feels like i've just killed someone.. even if it's just for a few secs.

I'm feeding the DRPA from the computer, amp on full throttle. is this right way?

Also, I can't really understand the concept with a too high power amp being bad in the situation. For example:

high power amp on full throttle, feed with sine wave and limit at 50v, then set a good relationship between tops and subs and remote the limiter with the gains on the mixer. why would this result in squashing? as long as you keep an eye on the limiter I can't see whats bad with high headroom on amp?

What concerns me the most is that I can't find any good settings for a reliable limiter on the subs.

But the T30 is really bad-ass..

You need to understand system gain structure. There will be a link in the education section for you. Cooks version: Every unit in the signal chain has a minimum and maximum gain setting, in and out, for an acceptable noise and distortion level in realtion to the actual signal you want to hear. In the extreme, say you have a "gigawatt" amp, and limit it to -30dB, as soon as you turn on the mixer you get a bit of hum and no music at all! That's what you are up against, to a lesser degree, if your amp is way too powerful.

I get you, squashed/limited signal is not what I desire. But wouldn't that be the situation only if you had some serious gain staging AND full throttle on the amp, if you dial the signal with the gain/master on the mixer you won't have to push the limiter too hard?

Still... I won't dare to "set and forget" as long as I'm not totally sure that my limiter is working as desired. How come no info is included in the plans on how to set the limiter correctly? Or am I missing the point somewhere? I'm sorry for being noob if that's the case..

[Gregory East]

Dialing back the amp doesn't help with system headroom unless you dial up the limiter, then you are exposed to someone dialing the amp back up and blowing your drivers.

[Bill Fitzmaurice]

How come no info is included in the plans on how to set the limiter correctly? Or am I missing the point somewhere? I'm sorry for being noob if that's the case..

Only so much can be put into the plans. OTOH there's this:

http://billfitzmaurice.info/forum/viewforum.php?f=14

[Gregory East]

The detailed instructions aren't in the plans because systems are configured many different ways. The forum helps out anyone who doesn't understand the implementation of the basic instructions. EDIT see Bill already steered you in right direction!

"You must limit to x volts with sinewave or risk blowing your drivers", gives you a clear heads up.

[Dan30]

well 50v is 141.5 watts, 159v is 449 watts and that's the watt rating of the driver. All i'm saying is I wish the driver was safe within that extra 100v range.

I think your math might be a little off.

Watts = Volts squared/impedance
50*50/8 = 312.5 watts
159 * 159/8 = 3160 watts

Oh that makes a lot more sense. I thought 1w = 2.83v.

[Gregory East]

1W is made by 2.83V at 8 ohms.... bada-ching! Back to school for ye!

[Dan30]

1W is made by 2.83V at 8 ohms.... bada-ching! Back to school for ye!

I need to do some more reading but i'm on the right track now.

[Tom Smit]

I did some testing today,... Everytime I accidently feed the 3012lf with more than 50 volts it feels like i've just killed someone.. even if it's just for a few secs.

Do your voltage readings with the speakers disconnected from the amp!

[Dave Non-Zero]

the driverack PA doesnt have brickwall limiters!

they have a minimum attack time that will allow high transients through.

what does this mean? -
using pink noise and setting the output voltage of the amp to just below clip light comes on, you can turn the pink noise up as far as you want and the limiter will keep it from clipping. BUT. run some music with a beat thru, and turn it up and the limiters will be on, but the beat will still clip your amp.
the limiter takes a small amount of time to clamp down on the signal, allowing transients thru for a short while.

so you cannot rely on the driverack to completely save your drivers if you use a large amp and run it hard into the limiters.

[Dan30]

I'm still waiting on the d-fend. From what I read in the fEARful forum the soonest we could see them is mid November.

[Jon Barnhardt]

1W is made by 2.83V at 8 ohms.... bada-ching! Back to school for ye!

I need to do some more reading but i'm on the right track now.

See this thread for some voltage indexes: http://billfitzmaurice.info/forum/viewt ... =7&t=16062

[Bruce Weldy]

1W is made by 2.83V at 8 ohms.... bada-ching! Back to school for ye!

I need to do some more reading but i'm on the right track now.

See this thread for some voltage indexes: http://billfitzmaurice.info/forum/viewt ... =7&t=16062

Better yet, just use this...

http://www.sengpielaudio.com/calculator-ohm.htm