Musician Gear & Tech Discussion

I might be buying 2 Yamaha S15V's tomorrow.
(500 line /1000 program/2000 peak) aka 1000W@ 8 ohms.
Nice deal, dirt cheap.

I have a powered mixing desk that is blowing 250W at 4 ohms.
I have a power amp that I can connect that is also 250W at 4 ohms.

So, 250W at 4 ohms (x 2) = 500W at 4 ohms = 1000w at 8ohms, right?

So at that point, I will be able to push those S15V mains or 1000w@8ohms, correct?

That last thing I need is 2 mains that are so big I can't push em.
Advice? Comments? Sarcasm? lol

I might be buying 2 Yamaha S15V's tomorrow.
(500 line /1000 program/2000 peak) aka 1000W@ 8 ohms.
Nice deal, dirt cheap.

I have a powered mixing desk that is blowing 250W at 4 ohms.
I have a power amp that I can connect that is also 250W at 4 ohms.

So, 250W at 4 ohms (x 2) = 500W at 4 ohms = 1000w at 8ohms, right?

So at that point, I will be able to push those S15V mains or 1000w@8ohms, correct?

That last thing I need is 2 mains that are so big I can't push em.
Advice? Comments? Sarcasm? lol

The S15's are very bright in the high end. I used a pair of them with 4 18" subs and I would still have to cut back the 4,300 khz about 5 db.

I ran the crossover at 170hz and pushed them with 150 Watts RMS per side in a 600 person club. Worked just fine.

I'm pretty sure that an amp with 250 watt output @ 4 ohms will have an output of 125 watts at 8 ohms.

S215V is a pretty nice sounding speaker and is relatively efficient at 99db SPL @ 1w/1m. They don't need a lot of power to project a lot of sound.

@ 100w RMS= 119db SPL
@ 200w RMS= 122db SPL
@ 400w RMS= 125db SPL

Your 2 channel power will yield 125-150w RMS @ 8ohm each which should be plenty to fill a room. One could be used for mains and the other for monitors without much sacrifice in sound coverage.

I bought a pair of S115v for my car club and they cover outdoor events well.

Capt I use a pair of 2x15V Yamaha's.

If you run into one speaker and then run to the other speaker, in other words one speaker line, you will get 250 watts out of your mixer at 4 ohms.

If you run to one speaker from your amp it will see 8 ohms 125 watts.

It really depends on how you set it up, if it were me, I would run one speaker with the power from your mixer, and then hook the power amp up to your monitor send and use it in a stereo mode, that way you are putting 125 watts at 8 ohms into each speaker, should sound pretty good that way. You could have two totally different mixes going to compensate for how you set up.

Those speakers are more comfortable at 8 ohms. I personally dont like pushing a speaker into a lower ohm load, you are losing headroom when you do that and a hard hit could damage the speakers. I just always try to match the amps ohm load with the speaker ohm load, its more efficient that way.

Good Luck

Dont know if I made sense with that or not, but Im trying.

So, 250W at 4 ohms (x 2) = 500W at 4 ohms = 1000w at 8ohms, right?

250 watts at 8ohms, is the correct anwer from what I know

Yep I am confused..

My Yamaha power desk does 250 @ 4 ohms.

The Yamaha power amp I plan to hook up to it does 250 @ 4 ohms as well.


The S215V's are 1000 @ 8ohms.

Am I cracking up? I have no head wounds currently. lol

I am just running vocals, the rest are just pushing signal through their amps and the drummer is loud already. I don't need it to be deafening, I just need a little volume enough to be heard in conjunction to the regular racket.

Every time I get involved with a newer PA, it's like trying to swim the English channel.

Wattage ratings have gotten pretty confusing so I don't dwell on them much. Very few consistent rating standards you can trust these days. Just plug them in to your amp and they will be fine Scotty. Think of a speaker wattage rating as a "never exceed" limit. You can always run less power.

Yamaha S215Vs are rated for 500w RMS, 1000w program, 2000w peak. You are good to go!
http://www.yamahaproaudio.com/global/en ... ations.jsp

More on speaker impedance and amp ratings:
http://www.prestonelectronics.com/audio/Impedance.htm

Thanks to all of you...

Soon as it gets all technical, I can feel my balls trying to buy a plane ticket to Acapulco. lol

I am going to start stalking a technician to kidnap and chain up at the house.

"If you wanna eat this t-bone steak dinner I just brought in, you'll hook up my recording studio in the basement and no backtalk or you get the whip and no steak dinner FOR SURE."

Come on, I just got it from the Longhorn Saloon.
I even brought beer and Creme Brulee for desert.. lol

Capt back to what I said earlier.

Hook up one speaker to the power amp in your board.

If your board has a monitor send, then run out of that into the other power amp and hook a speaker to it.

Your main output for the board will control the gain or volume of one speaker, the monito out send will control the volume to the other amp.

This will give you a stereo system, with independent volume control over each speaker.

Over the years I have hodgepodged so many PA Systems together with whatever equipment is available.


Our system we run 2 1x18V Yamaha subs, I bridged two QSC 1450 amps together. I run a speaker line out of each in the bridged mode to each speaker. From the specs I think Im getting about 7-900 watts per amp into each sub.

For the 2x15V tops Im using a Yamaha 7000 series amp. The 2x15Vs are 4 ohm cabs if I remember correctly. I think when I set it up a couple of years ago, we figured we were getting about 1100 watts into each top.

In essence we are getting around 3600 watts running the speakers, At one time I was using one QSC 1450 to run both subs, it just didnt have the bottom kick that we expected.

For monitors we run two mixes, into an older QSC 1300 amp. Basically I have two peavey montiors running on eahc side of the amp. Running the two 8 ohm cabs in series makes the amp see or feel 4 ohms. I figure we are putting 500 watts at 4ohms out each side of that power amp, so that makes each speaker see 250 watts.

It can get really confusing.

If you run a couple of speakers together basically you are dropping the ohm load on the speakers. so 2 8 ohm speakers together = 4 ohms.

With that in mind, I would say make sure you dont drop your amps into the 2 ohm range, at that point if you get some sort of serious spike thru the amp, it could either damage the speaker or the amp.

Im sure Ive confused you way too much, but any other questions just post them and I will try to give a decent answer.

Good Luck

Just a quick note on loads/speakers (Scott - better take the 'engineer' title away!)
If you hook up two 8 ohm speakers in parallel (that means both speaker - and + wires are hooked together, you show a 4 ohm load (approximate) to the amp.
If you hook up two 8 ohm speakers in series (that means - from one speaker to amp, + from that speaker to the - on the other speaker, then the + from the other speaker to the amp), you show a 16 ohm load to the amp.

So it all boils down to how you hook things together and how the speaker jacks are wired together.

Good catch JW. If they are S215s they are indeed 4ohm cabs. S115s are 8 ohm cabs. This is an important difference that if ignored could mean a power amp barbeque. One separate 250w/4 ohm amp per speaker would safely feed these S215s and result in 123db SPL. Plenty. The amps would be working pretty hard though.

As to Mike's input, one "could" wire the cabs externally in series for 8 ohms total load but why would you? It just reduces the available power to your speakers and you end up with only about 65w per speaker instead of 250. If you forget your tricky wiring sequence just once and plug in a standard speaker cord for a 2 ohm load... instant power amp BBQ

The ideal power amp for these speakers would be 1000W/side at 4ohms and run easily into a 2 ohm load without overheating and tripping overload protection.

This is one of many reasons why I favor modern bi-amplified (self powered) Speakers like JBL, EV, Mackie, QSC. No math involved and the amps and speakers are carefully engineered and matched at the factory. Also 127db SPL from a 40lb bi-amped box vs 123db from a 100 lb passive box so my back thanks me.

Yea the powered speakers are nice unless the power amp goes out, then you are without both a speaker and power.

I havent personally used them, but it seems like a great idea, so the power and speaker are matched.

Yea the powered speakers are nice unless the power amp goes out, then you are without both a speaker and power.

It is certainly possible, I have just never seen that happen. Internally bi-amped speakers have been widely available for about 15 yrs now and they are just dead-nuts reliable.

I just remember taking a power amp to a tech a few years ago and he had some mackie powered subs lining a wall in his shop, waiting for parts.