Most Speakers on One Amp

[wr_anders]

How would I figure out the maximum number of speakers a particular amp could run?

Here is the hypothetical situation: I have, say, 8 T36s. The horns are loaded with the recommended 3015lf. It handles 450 w/RMS. To power them I have a Crown XTi 2000. All of the speakers wired together comes to a 4 ohm load (plus the little extra the horns give). In bridged-mono mode this amp provides 2000 watts of power at 4 ohms.

So would this amp be enough to power said stack of subs? If not, how do I calculate the maximum?

[SoundInMotionDJ]

Here is the hypothetical situation: I have, say, 8 T36s. The horns are loaded with the recommended 3015lf. It handles 450 w/RMS. To power them I have a Crown XTi 2000. All of the speakers wired together comes to a 4 ohm load (plus the little extra the horns give). In bridged-mono mode this amp provides 2000 watts of power at 4 ohms.

How are you getting the resultant impedance of eight T36's? The T36 adds 4ohms to the impedance of the driver. Without an overly complex series/parallel wiring scheme, there is no way to get 8 cabinets to a 4 ohm load.

With an 8ohm driver (e.g. 3015LF) the impedance of multiple cabs will be:

[*]1 cab = 12 ohms
[*]2 cabs = 6 ohms
[*]3 cabs = 4 ohms
[*]4 cabs = 3 ohms

That is above the minimum load per channel of the Crown Xti 2000 amp. The amp will provide about 900w into a 3 ohm load per channel. That is 300w per driver, and with a stack of 8 still represents significant overkill for most applications. Generally as the pile of cabinets grows, the need to run them over 50% of their power handling declines. Remember that even in the best case, doubling the input power will add +3dB to the output.

The 3015LF is an awesome driver, and can actually make SPL with 450w of power. Eight such drivers can make use of 3600w of power! That is approaching the theoretical limit of an amps ability to source current from the wall. If you really need to drive all eight cabinets to their limit, a second amp with a second electrical circuit should be a requirement. In addition, I would not drive any cabinet without a hard limiter in the system - and that is especially true if you are planning to drive to anywhere near the power handling limit of the driver.

So would this amp be enough to power said stack of subs? If not, how do I calculate the maximum?

The Crown XTI 2000 is enough to power the stack (HINT: underpowering is a myth). That said, I would use two cabinets per channel, and use a total of four channels to drive eight T36's. That represents a margin of safety that will allow the amp to run at less than 1.21 Gigawats of output, stay cooler, and prolong the life of all the components.

--Stan Graves

[Ron K]

How would I figure out the maximum number of speakers a particular amp could run?

Here is the hypothetical situation: I have, say, 8 T36s. The horns are loaded with the recommended 3015lf. It handles 450 w/RMS. To power them I have a Crown XTi 2000. All of the speakers wired together comes to a 4 ohm load (plus the little extra the horns give). In bridged-mono mode this amp provides 2000 watts of power at 4 ohms.

So would this amp be enough to power said stack of subs? If not, how do I calculate the maximum?

If you did a complete series parallel of all 8 they would each see roughly 250 watts.Since the enclosure adds some impedance probably even a bit less then 250 each. Being a 450 watt driver I'd say anything over 300 RMS is going to push it into power compression anyways whereby rendering no more system gain!

2000@4ohms is probably a bit shy for bringing the whole load up to full level but will still be plenty loud.If stacked and V plated their gonna get pretty loud over the entire passband even at 100 Watts of power to each driver!

However I would not run that XTI into 4ohms bridged at full tilt!It's protection scheme is still top rate but the distortion spec is really gonna get ugly when you push it hard.I'd either buy another amp or if you must run all 8 simply keep the level below 3/4 power preferably down around 1/3 power!

My experience with the XTI in bridged at 4 is it gets kinda ugly early on and you can hear that distortion.Also they are not great sub amps to begin with.I like them on mid/highs but not on subs.Old iron has more hit on subs IMHO.

[wr_anders]

Thanks for the info guys.

Ron, what amp do you recommend for subs?

[WiSounds]

Old iron has more hit on subs IMHO.

This is why the good old capacitors and transformers in my FTX-2001s are still my first choice. They rely less on the wall outlet for dynamic peaks.

[wr_anders]

[This is why the good old capacitors and transformers in my FTX-2001s are still my first choice. They rely less on the wall outlet for dynamic peaks.

Where did you get your Ashlys, Wi?
What are some comparable amps? Right now I'm just looking for choices.

[WiSounds]

I live in Rochester NY, roughly 15 min from the factory. Have gotten them all used locally and one from their service manager.

I'm also a dealer, that's a major reason why I have an NE8800m.

[wr_anders]

Are there any amps that are comparable to your Ashlys?
There aren't many places that I've found that sell them and the ones that I have, well, they're a bit out of my price range. lol

[WiSounds]

You'll find QSC and Crown to be the norm around here. Ashly would be the higher end, but now it is readily available to everyone here.

[wr_anders]

What are the opinions of the Europower amps?

Generally, I try to stay away from Behringer, but I haven't read anything bad about them, other than weight complaints.

[SoundInMotionDJ]

What are the opinions of the Europower amps?

Generally, I try to stay away from Behringer, but I haven't read anything bad about them, other than weight complaints.

I have eight EP2500 amps. They are reasonable value for $. I rarely run them below a 4ohm load per channel, and I have never demanded more than half their rated output for the peaks. The original pair I bought have been used for over three years...and have been used at about 100 gigs in that time.

--Stan Graves

[wr_anders]

The original pair I bought have been used for over three years...and have been used at about 100 gigs in that time.

So if I got a pair, just don't run them at full? That should be easy enough. Especially with the price tag. If i need more power, just get another.
I've been considering them for the price per watt, but wasn't sure about the quality.

I'm more comfortable with running a a few lower quality amps 70% than one high quality amp at 100%, especially since my budget would be stretched with the high quality ones.

[SoundInMotionDJ]

So if I got a pair, just don't run them at full? That should be easy enough. Especially with the price tag. If i need more power, just get another.
I've been considering them for the price per watt, but wasn't sure about the quality.

I'm more comfortable with running a a few lower quality amps 70% than one high quality amp at 100%, especially since my budget would be stretched with the high quality ones.

More SPL = More Hardware.

Keep in mind that the EP4000 is just an EP2500 after the marketing department got hold of the spec sheet. Even so, a pair of amps is plenty to power the eight subs.

[Ron K]

Thanks for the info guys.

Ron, what amp do you recommend for subs?

Older Crown Macros1200,2400,3600,5000, Crest 8001,9001, Peavey CS1000 and up.

If you are looking for cheap find some old Crown PB/PT2s or 3s and run them bridged for some real cheap high power with good hit and control!Older MicroTechs are ok too.