Re: Which amp to use with a T-18, with recommended MCM 8” dr
Posted: Sat Apr 14, 2012 12:23 am
by BrentEvans
beeherd wrote:
The IPR1600 is the least powerful of the IPR's and its output is about 4x the RMS power handling at 4 ohms of the MCM rating. I want my amp to have no more than 2x RMS aka 1x program. Too much risk of a blown driver otherwise. If there were 8 ohm versions available, no problem.
Double the power is 3db, quadruple the power is 6db. Further, just because an amp has less "rated" power, there is no guarantee that you won't blow your drivers. Add to that that an amp running at 1/4 its rated power will run cool and clear. THD increases as power used increases.
Any amp (even one with less rated power than your driver) can deliver a momentary surge that's enough to toast a driver.
If you want to protect your speakers, buy a limiter. For the price you're paying for that EV, you can get a single IPR1600 (which will drive 4 4 ohm cabs with no problem) and a DCX2496/BBE DS24/DRPA+. This is a MUCH better solution.
Re: Which amp to use with a T-18, with recommended MCM 8” dr
Posted: Sun Apr 15, 2012 12:39 am
by beeherd
BrentEvans wrote:
beeherd wrote:
The IPR1600 is the least powerful of the IPR's and its output is about 4x the RMS power handling at 4 ohms of the MCM rating. I want my amp to have no more than 2x RMS aka 1x program. Too much risk of a blown driver otherwise. If there were 8 ohm versions available, no problem.
Double the power is 3db, quadruple the power is 6db. Further, just because an amp has less "rated" power, there is no guarantee that you won't blow your drivers. Add to that that an amp running at 1/4 its rated power will run cool and clear. THD increases as power used increases.
Any amp (even one with less rated power than your driver) can deliver a momentary surge that's enough to toast a driver.
If you want to protect your speakers, buy a limiter. For the price you're paying for that EV, you can get a single IPR1600 (which will drive 4 4 ohm cabs with no problem) and a DCX2496/BBE DS24/DRPA+. This is a MUCH better solution.
Hmmm, I don't think I've ever heard anyone offer that strategy before, but it does make some sense. Do you think I could try this with a RMX2450, DCX2496 and a 60w rated Kustom KSC 10ML monitor. I don't mind risking frying this speaker to test it and I have this gear. Of course if this does work, of course I could use the RMX2450 instead of buying an IPR1600. Failing that, I could find a cheap, slightly higher rated speaker used to test it on.
Re: Which amp to use with a T-18, with recommended MCM 8” dr
Posted: Sun Apr 15, 2012 1:25 am
by Gregory East
Build something with bp102 and limit. Mcm are ok for playthings but for work you want good stuff. Two t39 make mondo thump. One 3012lf t39 makes nearly same thump.
Re: Which amp to use with a T-18, with recommended MCM 8” dr
Posted: Sun Apr 15, 2012 8:52 am
by BrentEvans
beeherd wrote:
Hmmm, I don't think I've ever heard anyone offer that strategy before, but it does make some sense. Do you think I could try this with a RMX2450, DCX2496 and a 60w rated Kustom KSC 10ML monitor. I don't mind risking frying this speaker to test it and I have this gear. Of course if this does work, of course I could use the RMX2450 instead of buying an IPR1600. Failing that, I could find a cheap, slightly higher rated speaker used to test it on.
You just haven't hung around the forum here long enough. That's what we all do (or should be doing) and is the method recommended in the plans for pro cabs. You could try it with your monitor, but it might be a bit misleading in that you'll hear both the distortion when the cab gets too much juice, and possibly any distortion caused by the limiter. With horn subs, distortion gets filtered out to a large degree, so you have to do it by the numbers and measurements.
Gregory East wrote:Build something with bp102 and limit. Mcm are ok for playthings but for work you want good stuff. Two t39 make mondo thump. One 3012lf t39 makes nearly same thump.
Have to +1 this... if you feel like you're going to be pushing it... get the better drivers and build the right cab. T18 is really a home cab, not a pro cab.
Re: Which amp to use with a T-18, with recommended MCM 8” dr
Posted: Sun Apr 15, 2012 5:32 pm
by beeherd
BrentEvans wrote:
You just haven't hung around the forum here long enough. That's what we all do (or should be doing) and is the method recommended in the plans for pro cabs. You could try it with your monitor, but it might be a bit misleading in that you'll hear both the distortion when the cab gets too much juice, and possibly any distortion caused by the limiter. With horn subs, distortion gets filtered out to a large degree, so you have to do it by the numbers and measurements.
If it's working, then it shouldn't be getting too much juice. If it's not, then it's putting my drivers in danger of being over-driven which is why I would be hearing distortion from that source. And really I don't care what it sounds like once driven into limiting because limiting should only be for the occasional transient spike caused by things like a dropped mic, or an accident that causes a cable to be pulled out earlier in the signal chain. The point of the test is to see what happens to the driver in terms of protection.
Anyway, I'm not sure when this test will happen, but pretty sure I'll try it. I'm wondering if I shouldn't be trying it on something a little closer to the real scenario. Being a little out of my area of comfort zone here, I'll try to put my concerns in the best terminology I can muster... I know enough about limiters to understand the difference between soft and hard limiting. A limiter that cut everything off all at once would sound awful if it was being run into with any degree of frequency. A limiter that cuts everything off gradually will sound better and in practice, a compromise position is usually taken. That said, I'm wondering if given an amp that is powering several times higher than even peak ratings would end up limiting so far down that one would effectively end up with little or even NO output because it would START limiting with the tiniest bit of power.
Gregory East wrote:Build something with bp102 and limit. Mcm are ok for playthings but for work you want good stuff. Two t39 make mondo thump. One 3012lf t39 makes nearly same thump.
BrentEvans wrote:Have to +1 this... if you feel like you're going to be pushing it... get the better drivers and build the right cab. T18 is really a home cab, not a pro cab.
Yeah, I was really trying to find a very small sub and I didn't like seeing the MCM as the only recommended driver on the T18's. I'd prefer something really solid like a LAB12 or Kappalite 3012LF but at a scale that would fit the smaller design of the T18. I don't mind spending more if it gives me a high output, smaller cab -- I'd like to avoid the "It looks too loud" criticism which is stupid but nonetheless is something a wedding DJ puts up with. I guess I'm asking too much to look for what amounts to a LAB8 and a horn cab designed for it.
For the piezo referred to, would this work? http://www.parts-express.com/pe/showdet ... r=292-2648
Pyle Pro PSN1167 3.5" 400W Horn Piezo
Specifications: • Power handling: 200 watts RMS/400 watts max • Impedance: 4-8 ohm • Frequency response: 3.5 - 25 kHz • SPL: 93 dB 1W/1m • Tweeter dimensions: Cutout: 2.75" x 2.75" • Overall: 3.5" x 3.5" • Mounting depth: 2.8".
I'm assuming I could just build a small box, mount the piezo in it and connect the leads to a 1/4" T/S jack for testing purposes? Does it work for testing clipping one subwoofer range size waves? That doesn't make sense to me, but then I don't understand the whole Piezo as test equipment thing anyway... just following the tried and true method.
Re: Which amp to use with a T-18, with recommended MCM 8” dr
Posted: Thu May 10, 2012 11:01 pm
by el_ingeniero
When you hear Pyle, you should be thinking Pyle of crap.
Why not build T24 slims with BP102 drivers? At 14 or 16 inches, you can slip them under tables or behind sofas or wherever ...
Re: Which amp to use with a T-18, with recommended MCM 8” dr
Posted: Fri May 11, 2012 12:09 am
by beeherd
I would never use pyle for my cabinets... I was only wondering if they were okay for testing purposes. If no, what should I look for?
That's what we all do (or should be doing) and is the method recommended in the plans for pro cabs. You could try it with your monitor, but it might be a bit misleading in that you'll hear both the distortion when the cab gets too much juice, and possibly any distortion caused by the limiter. With horn subs, distortion gets filtered out to a large degree, so you have to do it by the numbers and measurements.