BillFitzmaurice.info

So how do you exactly match amp wattage and ohms to certain speaker or combination of speakers?
Do you go for the total of RMS total of peak or total of program wattage and get amp that have the wattage rating equal or higher ??
And when resistance changes lets say from 8 to 4 does the power requirements change?
Thank you.

u4david wrote:So how do you exactly match amp wattage and ohms to certain speaker or combination of speakers?
Do you go for the total of RMS total of peak or total of program wattage and get amp that have the wattage rating equal or higher ??
And when resistance changes lets say from 8 to 4 does the power requirements change?
Thank you.

My understanding is you need to know the volts your driver will handle (there's a formula for that on the forum somewhere) and it's likely in your plans too. WARNING: this is my .02. Look around here more...much more for verification...I just learned about this myself.

volts from amp = square root(watts * ohms)

I'm running 3012lf drivers in two Tuba 30's (8 ohms each, 4 ohm load) which go to 50 volts max....

If I run an XLS 1500, which does 525 per side at 4 ohms, here's the volts I'll get:

45.8 V = square root(525 watts * 4 ohms)

I was surprised an amp that small was all I needed. That would be perfect for my two Tubas running 3012lfs parallel off one side of that amp, so I could run two more off the other side. And of course you MUST a limiter to catch transients from the amp. Bill's advice is to not run all the way max on the volts as it places alot of stress on the system. I'm shooting for about 40 V. Past that point you're recommended to have additional boxes. 35 volts is making my two 18" Tuba 30's sing outside V plated with no loading.

Can anyone second this as looking OK?...

Square root?oh no,something I slept in the math class through?!
I tried and tried to understand the square root in bill's myth-busters about speaker damage causes he posted- but I have no clue still what is that.

So can someone hold math class in relation to speaker /amp specs?

http://www.math.com/students/calculator ... e-root.htm
http://en.wikipedia.org/wiki/Square_root

doncolga wrote:Can anyone second this as looking OK?...

That checks good. The force is strong with this one.

Tom Smit wrote:http://www.math.com/students/calculator ... e-root.htm
http://en.wikipedia.org/wiki/Square_root

+1 and also: http://www.billfitzmaurice.info/forum/v ... =1&t=13307 (the 5th bullet statement in particular)

u4david wrote:Square root?oh no,something I slept in the math class through?!

That sucks, because all that stuff they tried to teach us in high school, you know the stuff where everyone was saying, "When the hell am I ever going to use that?", is used here. Time to step up to the plate, better late than never.

u4david wrote:So how do you exactly match amp wattage and ohms to certain speaker or combination of speakers?
Do you go for the total of RMS total of peak or total of program wattage and get amp that have the wattage rating equal or higher ??
And when resistance changes lets say from 8 to 4 does the power requirements change?
Thank you.

Simplest thing to do is determine the RMS (PE) rating (not peak) of a given woofer driver and match your amp to that.

For example - for a pair of DLII2510 loaded Jack 10, you'll want an amp capable of up to 250W RMS @ 8 ohms per channel. Fortunately most, even the cheapest, power amps are capable of this output.

OR ... the simple way ... ask the pros here on the forum ... ie ... I need to power X amount of X cabs, please recommend an appropriate amp. Most of the time, the answers will be "the usual suspects" ... popular models by Crown, QSC, Peavey, and Behringer which have proven to be reliable and are good bang-for-the-buck. The model to choose will depend on your particular needs and budget.

Separate scenario that i need to know what do i need to have.Each scenario is independent of the others.
1-To power one jack10 w/ delta 2510s and 12 array tweets>what amp do i need to run this?
2-To power 4x jacks10 (same as above) >on ONE CHANEL what amp do I need?
3-To power 4x jacks10(same as above)> two per Chanel what amp needed?


Thank you.
I will research how to do the math my self but till then please help me.

u4david wrote:Separate scenario that i need to know what do i need to have.Each scenario is independent of the others.
1-To power one jack10 w/ delta 2510s and 12 array tweets>what amp do i need to run this?
2-To power 4x jacks10 (same as above) >on ONE CHANEL what amp do I need?
3-To power 4x jacks10(same as above)> two per Chanel what amp needed?


Thank you.
I will research how to do the math my self but till then please help me.

Any power amp that can supply 250W RMS @ 8 ohms would work well in those scenarios. Amps like this typically put out 500W @ 4 ohms and 1000W @ 2 ohms.

I like the Behringer EP4000 - solid amp for an inexpensive price. It would meet your need in each of the above scenarios for about $300.

I thought you bought plans already?

If you reeeeealllllllly want to put put four on 1 channel it had better be a reeeeaaall amp that can do 2 ohms or else push 600W into 8 ohms. iirc 2510's are ok with 250W but 150W would still make a lot of noise.

Gregory East wrote:I thought you bought plans already?

If you reeeeealllllllly want to put put four on 1 channel it had better be a reeeeaaall amp that can do 2 ohms or else push 600W into 8 ohms. iirc 2510's are ok with 250W but 150W would still make a lot of noise.

Will the peavey ipr-1600 have enough to run the 4 jacks ?I mean enough to run them GOOD and mello and also GOOD and LOUD as well ?
# 530W RMS x 2 at 4 ohms
# 800W RMS x 2 at 2 ohms

u4david wrote:

Gregory East wrote:I thought you bought plans already?

If you reeeeealllllllly want to put put four on 1 channel it had better be a reeeeaaall amp that can do 2 ohms or else push 600W into 8 ohms. iirc 2510's are ok with 250W but 150W would still make a lot of noise.

Will the peavey ipr-1600 have enough to run the 4 jacks ?I mean enough to run them GOOD and mello and also GOOD and LOUD as well ?
# 530W RMS x 2 at 4 ohms
# 800W RMS x 2 at 2 ohms

Yes, I believe that would work just fine for gig-level volumes.

the speakers I'm using on my jacks are actually 150rms as they are discontinued mcmelectronics models. However, I can run my xls402 and my behringer powered mixer to clipping and the Jacks are fine. Personally, I like to power my speakers with 2x the rated rms power you never play pure sine waves in real life situations and the speaker is able to take more power than the rms for short bursts; these peaks are what keeps dynamics as anything that is overly compressed will sound lifeless.

Right now, americanmusical (and I think just about every other website) had the old xls' on sale. The 402 is at $199. But yes, the 402 is actually pretty ok match for the jacks while the 602 would be even better as long as you don't abuse the speakers with it. Of course, you can use any other amp as they're pretty similar as long as they the watts you want.

And if you want to run the four jack off one channel you will need something that is rated at 2 ohm stable (per channel). Like this, you can run all four off once channel. I think the xti and the new xls drivecore series can do this, as well as the newer stuff(like the IPR). However, what I do when I need to run my four jacks is run the monitor off my powered mixer and the four jacks off my amp. Remember that just like you can abuse drivers, you can also abuse amps.

Gregory East wrote:I thought you bought plans already?

If you reeeeealllllllly want to put put four on 1 channel it had better be a reeeeaaall amp that can do 2 ohms or else push 600W into 8 ohms. iirc 2510's are ok with 250W but 150W would still make a lot of noise.

He could run series/parallel for 4 Jacks = 8Ohms

Harley wrote:He could run series/parallel for 4 Jacks = 8Ohms

He'd need a pretty beefy amp to run enough watts / volts into four series/parallel 2510s @ 8 ohms, because the series circuit splits the voltage. OTOH, running four in parallel off one side of an amp (2 ohms) isn't the greatest idea, either, especially if it's being pushed pretty hard.