Karaoke Forums

Hi All,
As promised, I am getting back to y'all, to let you know what I ended up getting.
I got Yamaha's EMX512SC mixer and 2 - S115V speakers along with a Shure SM58 mic 2 days ago.
What I'm confused about is that the powered mixer seems under powered for the speakers, and since I have no clue about power ratings of mixers and speakers, I'm gonna need your help, please.
The mixer is rated for 500W @ 4 ohms and 350W @ 8 ohms.
The speakers are rated for "Noise 250W" "PGM 500W" "MAX 1000W" and they are 8 ohms.
Is this a good match - mixer and speakers?
If NO how do I correct the mismatch?
Can't return them to store, since it was a cash deal.
Thanks alot in advanced, and happy karaokeing to All.

Ideally for those speakers you'd want an amp that pushes 500 watts into 8 ohms to be ran efficiently.  You want your power rating to match the speakers 'program' rating which in this case is 500 watts.  350 is a little underpowered for those, however chances are unless you are really cranking the volume up, you aren't going to have any problems.  Without getting a different amp (you can get an external) there is nothing you can do to match the power.

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.........Yep, your mixer is rated at 350 watts per side with 8 ohm speakers. And like The Lonman said, they would prefer 500 each.

Best way to run those at high volume levels is to reduce bass levels. Bass tones rob the lions share of amp power and then the horns can be damaged.

I bet you have plans to add a subwoofer or maybe even a pair of them eventually, right?....That's cool cause then you can power the subs off a separate amp or buy powered subs with their amp built in.

Whenever you do add separately powered sub/subs, the mixer amp will then be a great match for your speakers because those power hungry bass tones will be removed from the main cabs and you can crank them to their max potential without worry.

Till then, please show some restraint or you really can damage your new speakers with too little power.

Edited:    OOOOPPPPS! Wait a minute!

Karyoker, I need you to look at this block diagram of his mixer.

http://www.yamaha.com/yamahavgn/Documen ... _Block.pdf

See if there is a way for him to feed subs off either the line level outs or the monitor jacks on the front.....All the powered connections are in the back, the front ones are line level......The reason I need you to look at the diagram is to see if the amp gets cut out automatically whenever you jack in to the line level jacks.....Some powered mixers are that ways.....It is incorporated in the line level jack via a special contact that 'makes' whenever you insert a plug.

I can't tell by looking, and owners manual doesn't say(unless I missed it)...Maybe you can tell by looking at the block diagram.

Here is the owners manual:

http://www.yamaha.com/yamahavgn/Documen ... _Block.pdf

I actually started off with the exact same system when I first started karaoke and ran it hard without ever having any problems. However, my older version of this mixing amp had a BRIDGE mode where I could run it in bridged mono at 500 watts/channel into 8ohms with the same amp. They probably eliminated this option because people who didn't know what they were doing were blowing up speakers left and right in bridge mode.

With what you have, however, try running the system in MONO mode (Main L+R). Then CUT the low/mid/high bands for each channel about 25%, but keep them in the same relationship as you normally would. That way it will sound the same but you'll rely on louder volumes instead of dB boosts to get the same sound, which is more efficient and creates more headroom to avoid damage. Also, keep your main volume level on the low side and rely on your volume levels for each channel to make your available power more efficient. Although you are not technically providing more clean power to the speakers, this makes underpowering the speakers not as dangerous (still watch your levels and stay well away from the clip range). Addind a sonic enhancer like the BBE362 will actually allign some frequencies to add even more headroom, then fill that headroom with a very efficient dB boost to the highs and lows, which will make things sound much better without much added risk.

Granted, your system would sound better with a 500 watt/channel onto 8ohm amp, you are realistically not going to blow anything up as long as you pay attention and understand what you are doing.

If you are concerned abotu running in MONO, know that though karoake tracks do often have stereo effects, you actually often lose quality by running it in stereo just for the fact that you are often playing in a larger space where the stereo effects are not able to converge, so in reality one side of the room/bar is getting half the music and the other half is getting the other but only a VERY SMALL convergence area is getting the full range stereo sound. In mono, both sides get the full sound, minus the effects of course but the overall sound is better for more of the listening area!!

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C Mc
KJ, FL

I use the same speakers but the older model ( Sv115iv) I believe the ratings are the same. Anywho I run them with a crown xls602 ( 370w x 2 @8ohms)  -
Sound Great and nevr (knock on wood) had any problems.
And before the Crown I ran them with a PeavyPV1200 (280watts x 2 @8ohms)
Again no problem as long as you don't PUSH THE VOLUME TO THE MAX

Again, that's the whole key.  You can do trickery eq cuts (which will actually have an opposite effect to what you'd want as you'd need to turn everything up higher to compensate for the lack of), or other things, but the main thing is still volume level.  You don't want to drive your amp into clipping - which is the big speaker killer.  What basically happens is you start out a show at regular volume levels, as more & more people come in, they start absorbing the sound & the volume needs to go up more, once that amp is running at it's max - cleanly (350 watts), if you need anymore  volume, it will be in the form of distortion.  You may not even audibly hear it, but your speakers will & feel the wrath.

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The Main or line out doesnt break the line to the amp the left only gives mono out and when plugged into the R jack it routes right only and left only.. The main out impedance is 10k and the input to the summing amp is at least that high or prob higher and there is no problem using both in fact that is the way is is designed... And the out leds will reflect the added load and can be trimmed accordingly...

 With the switch in the monitor mode (normal operation) the two channels are fed into a summing amp to actively make mono. Since the phase has been shifted 180 it is then fed through an inverter to get it back with the same phase as the monitor out...

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Thank you Karyoker!....Then he can simply add a subwoofer and amp by jacking into the front Left main out. Some power mixers will cut out the builtin amp when you do that. My old Audio Centron and several older Peaveys were like that.

TopherM, please understand I am not attempting to undermine you or discredit you, but actually most of what you said is simply wrong....if you reduce all three EQ settings the same degree all you have done is screw the gain structure coming into the strip....You first job as a sound engineer is to establish and preserve proper gain structure thru the mixer, and then thru the signal chain up to the power amps.

EQ adjustments are simply gain adjustments but for a narrow range of freqs....It is ok to cut one and maybe boost the other, but reducing all the same amount simply reduces gain for the total signal at the input....Pro Audio 101 teaches us to get as much gain as possible at the inputs to the mixer, then cut boost only the freqs required to maintain system gain structure, and then restore unity gain at the input if the cuts/boosts screwed it....so no, never reduce gain for the total signal at the EQ!

You set your mic gain by using your input level light for that channel, then if you cut all three EQ's, you will see that you now have to increase input gain to restore the input back to the same level at the light........In fact, whenever you reduce even one EQ, you will lower input gain to some degree, but if you cut all three, then you will lower it alot and violate the first rule in mixerboard operation: "Establish and Preserve Unity Gain!"

The reason you do not want to lower input gain to the total signal is that it will lower the dynamic range and headroom considerably, and you cannot get that back later in the signal chain at the master on the board...It has to occur at the mixer input.

His problem is that his amp is a little small for his speakers.....The only way to make sure his speakers survive is to not clip the amp......The best way to prevent clipping is to preserve amp power/headroom.....To do that, you cut the freqs that consume the most power first. That is always the bass/low freqs.

If you cut the bass freqs at the EQ, the fragile horns will not starve for power and suffer from the heat generated by clipping....I know it sounds odd to cut bass to preserve the highs, but that is how it works when running your mains off a full range signal....

As Lonman stated, the only time you need to cut low EQ on a skinny amp is when you are playing at higher volume levels.....It's ok to allow full signal to the speakers at lower volume levels-up to the point you start running out of amp power....cutting the bass then will allow you higher volume levels but without as much bass.

Also, running mono unbridged will not preserve amp power or provide additional headroom...Each speaker will still get the same power. The decision to run mono is simply based on how he needs to cover his audience....mono allows all audience members to hear all of the music, vice just what is coming out of the speaker closest to them.

Our friend is just starting out and has invested considerably in equipment, and he has also invested trust in us here. I apologize if I step on any toes when I say someone is wrong, but I only do so in an effort to preserve our rep as a knowelgable and helpful group...I also appreciate it whenever anyone here corrects me when I am wrong (politics/ethics excluded).

First off I would like to thank you all very much for your knowledgeable and quick replies, this is definitely a great site with a great bunch of people.
I talked to the store where I bought them and they are willing to do something for me. They are suggesting to get S112V speakers rated at 350W at 8 ohms or go with a power amp (Yamaha P5000S) and get myself a non powered mixer (maybe a CFX12 Mackie).
What do you guys think?
Thanks again.

Well going with the 112, you are going to lose your bass response, you could add a separate powered sub with the 112's & all would be good.  
Doing the separate amp & mixer combo will help the power matching, plus you'll be getting a better mixer IMO but it's going to cost about $500 give or take more than the Yamaha EMX512.  Like stated, unless you are really going to try & crank the volume, you are probably going to be fine.  YOu may not have as clean or full sound as you might at higher volume (onset of distortion).  I'm not sure if you stated what this system would be for - club or home.

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Easy

Just my .02 - keep the 15" and use with the amp/mixer you have.

You will be fine and find out you have enough power for most indoor gigs
unless you plan on playing at a large venue.

If they will allow you to return the powered mixer, then go for it. You will never regret the swap. Yes, keep the speakers and go with a properly matched amp.

The CFX12 or any similar mixer will more than satisfy your needs plus it will allow ten times more flexibility in the future. Flexibility and features that allow you to expand are almost always required (sometimes within days of your mixer purchase)....Especially when you are first learning the craft and simply didn't know enuff to buy that type mixer to start with.

Yes, get the Mackie or similar and get it out of the way so you don't slam into it like a brick wall eventually....If the price seems steep, consider a Behringer with same features. I do not regret buying Behringer. both are now being made in China and personally I can't see how Mackie can justify their high prices any longer.

Once again, thanks everyone.
I'll keep you all posted.
Keep on karaokeing.