BillFitzmaurice.info

27" 3012lf,

sounds great. Maybe not as loud as I imagined, but might very well be limiter settings or an air leak(gonna check for tomorrow, but ive been very generous with pl so I doubt it.)

Let me get it straight with setting limiter settings, ive got a very powerful peavey amp that delivers well over limits, I'm setting the amps gain on max, give it a 60 Hz sine wave from comp, and adjust limiter to as close as 50 as possible?

The problem for me was that I had two different noise generators, one for sine and one for music and the sine one being much higher.

What sound am I supposed to use when setting limiters? Should I use same generator(like Winamp for example)?

Today my limiter were limiting all the time even if the voltage were jumpin around and just once in a while were around the max voltage.. is this supposed to be so?

Now i need some well earned sleep.. goodnite

Awesome man. I hope to make a couple that size as soon as I move some old gear. Wait till you add another. It'll be awesome. Then wait till you wall load...more awesome. Then wait till you v plate and corner load a pair.

I used sine waves and fed a few different ones to mine. The problem I had with my previous super size amp was that when my mixer output was pretty strong (around 0 on the lights) and my amp was wide open, my limiter was completely squashing the signal from the mixer to keep me below 48-50 volts. I'm using a much smaller amp now, after selling the bigger one.

Its definitely safest to set the limiter with the amp wide open. Others will chime in with more input.

Congratulations on your build!

Donny

50V with a sinewave input is the limit for the cab.

When mixing, turn down your system gains so your music only hits the limiter occasionally and you will have some dynamic range and interesting sounds instead of a wall of squished sounds. You can still run the big amp full on but your system headroom in the mixer will be compromised. You lose range from your noise floor to "peak" output.

Otherwise you can turn down the amp and set the limiter with a higher input value that gives you more dynamic range upstream. Woe betide not running the amp choked down to suit though!

Or sell the big amp and get a smaller one.

Osse, like Donny said wait until you have the pair. I have 4 t30's(24" wide) with the 4012HO drivers and they are flipping awesome. I will be running
all 4 for the first time on the 21st of Oct. at a party at the local moose lodge. Here you can see pics from my last gig.http://www.billfitzmaurice.info/forum/v ... 13&t=16049

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..

osse wrote: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..

How much gain reduction is needed to keep you under 50? With my mixer putting out good, mine was like 18dB of gain reduction if I recall. Right now I've got to really push my mixer to get the limiter to engage. Seems like 40-50 hz hit mine hardest, so that's what I went by.

And also, I'm about to pain them soon, I've got equivalent paint to duratex, but it's expensive, is there any way to do any preparation work to reduce the amount of duratex used but still get great looking and working results? like coat it with black paint before or something..

osse wrote:And also, I'm about to pain them soon, I've got equivalent paint to duratex, but it's expensive, is there any way to do any preparation work to reduce the amount of duratex used but still get great looking and working results? like coat it with black paint before or something..

Seems like I did read that somewhere. That's all mine have had up to this point...a few coats of flat black. Maybe Santa will bring me some Duratex.

osse wrote:like coat it with black paint before or something..

you can use black paint to cover the wood first.

doncolga wrote:

osse wrote: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..

How much gain reduction is needed to keep you under 50? With my mixer putting out good, mine was like 18dB of gain reduction if I recall. Right now I've got to really push my mixer to get the limiter to engage. Seems like 40-50 hz hit mine hardest, so that's what I went by.

The gain staging in my comp is somewhat strange, I would prefer to do it with a mixer but when I'm cranking everything I think it's at LEAST 15 db's gain reduction... probably more, it's a wicked powerfull amp!

So I should search for the freq area where it hits them hardest, put the sinewave and measure/dial, and no murphy will come visit me and my precious driver aye?

This should be included in the plans actually... what freq you should use as if you use 100 hz it will be considerably lower than 30 hz, between 30 and 60-70 hz I think mine showed 30 volts difference... is this normal? feels kinda strange..!

How easy are the drivers to blow if driven too hard?

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.

osse wrote: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.

osse wrote: How easy are the drivers to blow if driven too hard?

How easy is it to get Bill to write IITP? About the same.

Use a sinewave within the guts of the sub's frequency range. At the low pass and the high pass the signal is being attenuated by the crossover.

subharmonic wrote:

osse wrote: How easy are the drivers to blow if driven too hard?

How easy is it to get Bill to write IITP? About the same.

+1. I read somewhere if you're one volt over, it's over.

It's a shame it won't protect to the 900W peak.