Thoughts on EV ZX5 90'S with a crown xls 2500

[SOUND PROOF]

I am thinking about getting another amp for my 2 EV ZX5 90'S, I want to use a crown xls 2500 will this be enough power for them or too much or just enough. I still have an issue with these numbers/ watts/ imp/ etc.. Please help..

[WRGKMC]

You get the best match when the head wattage matches the speakers. You surely wont hurt anything and the speakers will have plenty of headroom left over. They just wont be as loud as they can be if you run one on each channel. The cabs are good for 600W RMS and the head puts out 440W at 8 ohms per channel if you're running stereo. If you run the head mono with the channels bridged it should produce more then sufficient wattage You may want to check the manual.

 

It looks like 2X8 ohm cabs bridged produces 1550W total. That would be 775W per cab, and since you rarely if ever run a power head on max, it should cruise between 500 and 600W for your cabs without clipping or overheating. This is a Class D head too which is susceptible to shutting down if it overheats so running it lower them max is what I'd advise.

 

I will add, Crown makes some great amps, but I do think they overestimate the wattage a bit. It may produce that wattage under lab conditons (as your speaker do too) but in the real world, it may not be nearly as loud as you think.

 

[SOUND PROOF]

Thanks for the feed back and time and energy, I am presently using a qsc gx5, but it is in the shop. A buddy gave me a crown ce 2000 to borrow in the mean time and was going to buy it from him as a second amp. But that {censored}er is heavy and making me rethink it, trying to limit the weight of my gear (aint getting any younger). I guess I was reading these charts right, but I really like all the addons of this xls, and it seems to be the biggest they have in the series so I was kind of living in denial thinking it was fine. I would prefer to run each channel instead of bridged.. Maybe the Crown xti 4002 is a better bet?

[SOUND PROOF]

Also let me get this straight, if you run both channels bridged in theory you will be getting 1550 = 775 per speaker a total of 3100 watts altogether. Is this safe on the amp on gigs that might go longer then 4 hours or is it going to fry the amp faster then running one speaker per channel?

[WRGKMC]

No, the total bridged is 1550 and that's split between your two speakers. Your speakers handle 600W RMS each for a total of 1200W. The amp might be a little high running bridged but its unlikely you'd run the head maxed out. Either the head or speakers would likely begin to distort if you ran it full up.

 

You didn't mention what you'd be using this setup for. I assume its a PA given the fact the speakers and head are normally used for PA. Some guys use PA heads for guitar or bass rigs but they don't normally use PA cabs with horns. Keyboards can sound great through them but other rigs are better with normal instrument speakers.

 

 

You have to take into account how strong the signal feeding the head is. In order to get maximum wattage out of the head you have to feed the input the maximum line level input. If its a mixer its highly unlikely you'd run the channel and master faders full up. It would most likely feedback mics or sound awful. If you're just using it for vocals you'll probably be file. Its unlikely vocals will ever push the head to its maximum wattage huffing on a mic. If on the other hand, you ran a bass guitar in with a Line out on the bass amp, you definitely want more speaker wattage then the head can produce.

 

There is an additional option here. Don't know if you run monitors but you can run the mains at 4 ohms on one channel, and a pair of monitors on the other. If both sets of speakers are 8 ohms that means you have 4 ohms total on each channel. That would be 775 per channel which is more then enough for most clubs. Or if you had subs, you could run the subs with one channel and the mains with the other. The head has built in crossover equalization. You can roll the highs off on the one channel and feed the subs bass, roll the lows off on the other and feed your cans Mids and highs.

 

Again, its all about who much stuff you want to haul. I have a fairly big setup. I have 18" bins, A set of Yamaha 15:/horn cabs, Some cerwin Vega 15" with horns and some 10" cabs to add some mids. I can run all 4 cabs per channel per channel and get 2 ohms but I have two power heads so I split them up. I've taken the full setup to larger gigs but I'm getting up in years and hauling all that stuff plus my guitar rig barely fits in a long bed pickup truck. The older rack unit is made of 3/4" plywood and must weigh 400'bs. I can barely tilt and lift it onto the tailgate without throwing my back out.

 

I live the sound of the gear I have but allot of it is old school stuff. The Yamaha cabs sound great but even those are a Hernia waiting to happen. The Cerwin Vegas, forget it. They are smaller then the Yamaha but weigh just as much.

 

If and when I gig and need a PA, I pull a head out of the rack and take one set of cabs and that's it. I don't even use stage monitors.

If I gigged out more I'd sell the whole setup and find some lightweight setup that was easy to haul. I'd likely buy a powered head too. Having a mixers fine if youre paying a sound guy whose fading instruments in and out and adding effects. If I'm going to pay a sound guy, I'd rather just give him an extra $50 and have him haul his gear and run sound for the night. (or join a band like my last one that hauls their own gear and I can leave my rig setup in the studio)

[SOUND PROOF]

There is an additional option here. Don't know if you run monitors but you can run the mains at 4 ohms on one channel, and a pair of monitors on the other. If both sets of speakers are 8 ohms that means you have 4 ohms total on each channel. That would be 775 per channel which is more then enough for most clubs. Or if you had subs, you could run the subs with one channel and the mains with the other. The head has built in crossover equalization. You can roll the highs off on the one channel and feed the subs bass, roll the lows off on the other and feed your cans Mids and highs.

 

So in this senario you are really only giving each speaker (2 speakers on each channel=4speakers) about 387watts. Isnt that underpowering the speaker and causing damage?

 

I am running a PA for my quartet. Me on guitar and vocals, Upright Bass, Congas / Bongos, and a flute/ Alto Sax player. I am generally just using the ZX5'S fueled by a qsc gx5, with an ALLEN and Heath board. I run straight in with my acoustic guitar, 58 on my voice, 58 on my saxman, shure 81 on the congas, and bass running a line from his amp into the board. I am now thinking about using subs to maybe give a little more clarity to the mixs. But I dont care for alot of bottom end in my music, if the bassmans intonation is off just a little it screws up my ability to sing, I aint the best vocalist but I get work. I do alot of jazz standards and 70s covers with a good amount of blues in there too. A friend keeps encouraging the subs, to clean up the mixs a bit. But like you I aint getting any younger and been at it for about 30+ years now. I am doing a larger gig outside in october that will warrant subs a little more, or atleast rationalize more volume to me.

 

I dont really understand how to run 8hms speakers at 4ohms. I am assuming I dont really do anything physically it just happens when i dazzy chain two speakers per channel that is where the 4ohms comes into play, and when I run one speaker per channel it is 8hms. I guess I get confused at how the amp knows how to send 1550watts to the two speakers when it is on the bridged setting I am guessing that is why you set the little red thingy to bridged, because it takes the power from both channels (hence the name bridge)and creates one channel.

 

When I have to make changes to my system I always spend days reading about ohms and watts, and still remained baffled about it. I think you have actually helped lead me more toward an understanding about it then anyone has in the past on this forum or even writers on the internet. Thanks again,,

[WRGKMC]

You cant hurt a speaker with under wattage.

You'd blow a speaker (and maybe damage a head with the surge as the speaker coil blues in rare cases) if the heads too powerful for the speaker.

 

The only thing you may fail to do with a greatly underpowered speaker is fail to achieve the best sound quality. Speakers sound best when run at least 25% to around 75% of their max wattage. Run with a head too low and the minimum threshold is barely reached getting the cone moving. Too high and you obviously distortion and risk blowouts.

 

Manufacturers often match the RMS Rating of the Cabs and Head. This produces maximum transference of Frequency response. Analog Gear has a sweet spot. Its the nature of the beast when you dig into the electronics and study how transistors work and where on the amplification curve they produce maximum fidelity, loudness and minimal noise. In almost all cases its around 75% of max RMS. For your speakers that would be about 450W each. This gives you enough headroom for big transients and the clearest tones with minimum distortion.

 

Most people dial up that range anyway just using their ears. Even with driven guitar amps I've rarely just turned the knob to max. I

 

As far as ohms go. Google up ohms law. Two speakers of the same value run in parallel cuts the total impedance in half.

 

Think of it this way. If you take a shower and have pretty good water pressure going then someone flushes the toilet, the water pressure drops. With two speakers in parallel you have two paths for the electricity so the pressure through either one drops.

 

Pressure is your wattage dropping over the two speakers evenly.

 

The ohms goes down. Resistance is the opposite of conductance. If you connect two speakers, you have provided a second path for the current to pass through. Conductivity goes up with more paths, Resistance to electrical current goes down.

 

So you go from a single 8 ohm speaker seeing say 500W to two speakers in parallel producing 4 ohms.

 

NORMALLY. like with a fixed guitar amp, that 500W would be split and each speaker would see 250W.

 

PA Heads are different beasts. They have self adjusting variable voltage gain amplification stages. I could explain what that actually is but I don't see the need to bamboozle you with a bunch of technical stuff here.

The main thing is the head self adjusts its maximum wattage rating based on the load it sees. If you increase the load the total wattage goes up.

 

Main thing is with your setup you'd get 440W per speaker running it in stereo mode which is in the sweet spot range for those 8 ohm cabs and it should sound really tight and clean. if you run it Bridged, you should be able to get more then the full 600W per speaker. Again, its unlikely you'd ever push the two speakers that hard and can run find that way.

 

My own rig I have a CE1000 it produces 275W with 8 ohm cab. I have 400W drivers in main cabs so I can run it that way. My second set of cabs Has some 18's that can handle another 400W (I think) Running the two cabs in parallel, 2 per channel gives me 440W per channel. I'm well within the maximum wattage range.

 

I do have to figure what that 44W does when its split between the two speakers. Each speaker only sees 220W so I'm a bit low on the wattage I'd like to run. If I had 4 ohm drivers in the one set of cabs I'd be over just running the 2 cabs with 400W speakers but again, I never run my heads full up. and I can crank the master volumes down a little and keep the speakers safe.

 

The speakers do have safety circuit breakers. If they see too much power it trips the breaker instead of blowing the speakers. The head also has a built in compressor so it prevents big surges from hitting the speakers. Yours will likely have that too.

 

Not much more I can tell you besides Google up the manual. Crown makes some great heads.

 

You do have to remember, Wattage has absolutely nothing to do with loudness. Wattage is a power measurement, much like horsepower is in a car. You can have a Mack truck with high horsepower designed to pull heavy loads, but you can beat its speed from a stop on a bicycle. The truck uses that horsepower for creating great torque, not great speeds. The transmission and RPM is the key. A Mustang in comparison combines High Horsepower, High RPM's and an efficient transmission and it blows chunks when you step on it.

 

Speakers are the same way. You can have Low efficiency high wattage speakers designed for bass frequencies. The cones are stiff which makes them low efficient but they are beefy so they can handle the lows without blowing the cones out. On the other end you can have high efficient speakers with light cones that take very little power to produce allot of sound.

 

Speakers are rated in SPL DB levels. (Sound Pressure Level measured in decibels) This is an efficiency or sensitivity rating that tells you how well a speaker converts watts to decibels.

 

They get this rating by placing A microphone is placed 1 meter away from the speaker to measure the sound output (in decibels) with 1 watt of sound played through it.

 

say you have a 100w speaker that's rated for 90db. In order to make that speaker with a 100W amp. In order to make that speaker increase in decibels from say 84db to 87db, you have to double the wattage to 200w.

If you want to go from 87 to 91db you have to double the wattage again to 400W. The higher you go in wattage the smaller percentage of db is increased.

 

No look at the difference Say you have speakers that have an efficiency/sensitivity of 90db and you're running a 500W amp. To make those speakers 3db louder you have to give them 1000W. That's a whole lot of power for such little change in volume.

 

Now instead of going up in wattage with bigger power amps 9and their associated weight) you change the speakers to more efficient ones. If you go from 90db SPL to 112db. That would be equivalent to changing the amp power from 500W to 8000w when it comes to what the ears hear.

 

Not sure what kind of speakers you cabs have. PA speakers often tend to be in the low to mid 90's. This is just food for thought. If you want a loud setup always look at the speaker efficiency instead of massive amounts of wattage driving low efficiency. Chances are with highly efficient speakers you can drive cabs to be louder with a 100W head then you can low efficiency speakers with 2500W. Of course you have to factor in how good they sound and how much bass you're going to push.

 

A quick example is the horns in say a 600W cab like you have are only fed 50~75W. Everything else goes to driving the woofer because low frequencies take more power to produce so your ears can hear it.

[SOUND PROOF]

WRGKMC

Thanks again for all the info, and the clarity in which you explain things. Here is the speakers and specs I use and also the specs on the power amp that is in the shop that I want to upgrade... Still undecided about the crown xls 2500, but it seems to only be about 60watts shy of what I use now, but with more percs.. I take it from what you are telling me that 60watts isnt going to really make the speakers less loud... Maybe that is my best bet, its only 11lbs too

[WRGKMC]

I think you'll be OK. Crown makes some great power heads. I've had mine for a good 15 years and its performed flawlessly all that time. the most I may do is pull it out of the rack every so often and blow the dust out with compressed air. Besides abuse, dust and grime are the biggest causes of component failure. One humid days the dust draws in moisture and becomes conductive. If you're lucky this only increases noise. If you're unlucky, it can short voltages and lead to premature failures. Power heads get hot and often have fans to keep them cool. Because of this they are a magnet to dust. Getting in there with a dry paint brush to loosen the dirt and then blow it out is the best preventative medicine for all audio gear.