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Help! Need a sound lesson!
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Author:  JayM8377 [ Fri Dec 17, 2010 5:47 am ]
Post subject:  Help! Need a sound lesson!
I'm in the market for a powered mixer to pair with non-powered speakers. I see all these different wattages. 500W mixer, 400W speakers... what does it all mean? And what kind of power is needed for a small bar setting? Is 500W good?

To my understanding, the wattage on non-powered speakers is the Max they are able to put out without blowing up. The wattage on the mixer is the max amount of power it is capable of putting out.

If I'm wrong, someone please give me a sound lesson heh.

Currently, I would like to get the 500W PMP1000 Behringer powered mixer, and pair it with Behringer non-powered speakers. But I have nothing to compare it to. Would this suffice for small to medium-sized bar gigs and private parties, or should I push for something closer to 1000W??
Author:  TopherM [ Fri Dec 17, 2010 7:05 am ]
Post subject:  Re: Help! Need a sound lesson!
The Behringer PMP1000 actually puts out 500 watts at 4 ohms in bridge mode, so it is actually putting out 250 watts per channel at 4 ohms (to each speaker). The problem is that most speakers are NOT 4 ohm speakers, they are 8 ohms. The PMP1000 puts out a measley 90 watts/channel into 8 ohms.

This is not enough for anything other than a home system or a small coffee shop show for like 15 people. 90 watts is less than most home theater surround speakers require, and I'm talking the little bitty speakers with like 2-3" woofers. My 4" guitar practice amp is a 90 watt amp. Point being, you can't run a professional show off 180 watts of total power.

The accepted STANDARD for most pro karaoke setups would be 500 watts/channel at 8 ohms. Likewise, most pro-level PA speakers handle 500 watts at 8 ohms continuous power.

For small to medium gigs and private parties, I would not recommend going any lower than 300 watts/channel at 8 ohms on the amp, with corresponding speakers.

However, if you think you have any future in DJ/Karaoke work, go ahead and save the money to get an amp/speakers combo at 500 watts/channel @ 8 ohms.

These wattage numbers indicate how EFFICIENTLY your amp and speakers can reproduce the information contained in a song. In basic terms, a higher wattage handling means that the components of the amp and speaker will experience less stress at higher levels. a 90 watt speaker playing at high decibals/SPL is going to run HOT HOT HOT and have a greater risk of damage to all components than a 300 watt. A 500 watt seems to be efficient enough to run speakers for the 4-5 hours a karaoke show demands at high decibals/SPL without the risk for damage from inefficiency.

Also, speakers and amps with lower wattages, when asked to reproduce higher decibals/SPL (volume, basically), will do so by dropping some frequencies, so you just aren't getting as high a quality of output.

Think of it like a lightbulb, because lightbulbs work on the same basic principle. If you want to light a 1,000 square foot room, you don't want to get a 15 watt lightbulb, you want a 120 watt lightbulb. Will a 15 watt lightbulb "work" in that room. Well, technically, yes, but the quality of that light is pretty abismal. The 120 watt lightbulb does it more effectively with a higher quality of light. The higher the wattage handling of the lightbulb, the more efficient the light, the more it can output without overheating. Speakers/amps are the same way.

If you think you have any future in DJ/Karaoke work, save up the money and don't skimp. Get at least a 500 watt/8ohm amp and 500 watt CONTINUOUS speakers. The $400 you were going to spend on the Behringer PMP is going the cheapy route. Don't be the cheapy KJ. A good, quality amp and two good quality speakers in this range are going to run you about $800-1200 total, but are WELL worth the cost in the longrun.

Be careful, because as you have found with Behinger, lots of companies will use marketing ploys and misleading presentations on the power handling of their products. MOST PA speakers require an 8 ohm load. Behinger marketed that PMP as a 500 watt amp, well in the language most musicians speak, that is a 90 watt amp. That's very misleading if you ask me.

So, you want to make sure you dig into the user's manual and find the 8 ohm power rating, if the ad doesn't list it.

Also, for the speakers, you are going to see THREE rating numbers: RMS, Continuous, and Peak. You want to match the middle number, Continuous, to the PER CHANNEL power of the amp. So, for that 90 watt amp, it is only going to run 90 watt CONTINUOUS speakers efficiently. If you get a 500 watt/channel 8 ohm amp, as suggested, you want to find a 250/500/1000 (RMS/CONTINUOUS/PEAK) 8 ohm speaker. That means that the speaker can handle UP TO 1000 watt peaks before components start to FRY, therefore, you would be safe feeding it a 500 watt amp, and as long as you don't boost every frequency on the board and jack up the volume, you are not in danger of overheating the components of the speakers.

That all make sense? If you want some suggestions on amp/mixing amps and speaker combos, let us know your budget and I'll hook you up!
Author:  jerry12x [ Fri Dec 17, 2010 7:56 am ]
Post subject:  Re: Help! Need a sound lesson!
Yes, 200W RMS in bridged mode.

Why was there ever a need for Continuous and Peak?
I grew up with RMS.
I knew where I was then.
It does seem like some... take advantage of it.
Rant over.
Author:  TroyVnd27 [ Fri Dec 17, 2010 10:37 am ]
Post subject:  Re: Help! Need a sound lesson!
A good KJ/DJ does not run in bridged mode - IMO.
Author:  Lonman [ Fri Dec 17, 2010 10:53 am ]
Post subject:  Re: Help! Need a sound lesson!
Typically you want your amps RMS/continuos powert rating to match the speakers PROGRAM rating. Example Yamaha S115V speaker has 3 power ratings RMS/PROGRAM/PEAK. 250/500/1000 watts at 8 ohms. So for this particular speaker you would want an amp to push 500 watts (not PEAK output) per channel at 8 ohms for maximum efficiency.
Author:  letitrip [ Fri Dec 17, 2010 11:04 am ]
Post subject:  Re: Help! Need a sound lesson!
TroyVnd27 @ Fri Dec 17, 2010 12:37 pm wrote:
A good KJ/DJ does not run in bridged mode - IMO.


You said that's your opinion and you're entitled to it, but I'm curious why you would make such a blanket statement.

Is it that you don't believe a "good" KJ/DJ would ever want to run in Mono? There are certainly many environments (many of which KJs are forced to regularly play in) where stereo imaging just isn't effective. Many times with both large and small productions I've been in situations where running in mono is the best solution.

Is it that you have some believe that running an amplifier in bridged mode is bad? I'm curious what your concern is there as the impact to the amplifier really is nominal.

Just wanting to hear further explanation of why you hold the opinion you do.
Author:  letitrip [ Fri Dec 17, 2010 11:14 am ]
Post subject:  Re: Help! Need a sound lesson!
Pretty decent answers for the most part in this thread to the OP's question. One concept for you to remember Jay. There are two primary causes of speaker failure. The first, that everyone seems to know, is over-excursion. This is the result of over-powering a speaker and then sending large peak signals to the speaker. Over-excursion results in physical and usually visible damage to the speaker. The second cause is over-heating and can be caused by over-powering but more often than not is caused by distortion (which is often a result of running an underpowered system).

Amplifiers are not like car engines. Car engines usually perform best at speed (higher RPM's). Amplifiers conversely perform their best when they are not pushed very hard. The closer to peak output you drive an amplifier, the more distortion is generated. So the goal when buying a speaker and amplifier system is to ensure you have enough power to cover the venue you're working without having to drive the amps too hard (the additional room you have between that and their peak is referred to as headroom). I'd agree with the other poster who said that for most average sized bars, a system capable of 500W/Channel is a good start. Start there and find a pair of speakers who match up well to an amplifier of that capability using the guidelines that Lon mentioned.
Author:  TroyVnd27 [ Fri Dec 17, 2010 11:30 am ]
Post subject:  Re: Help! Need a sound lesson!
letitrip @ Fri Dec 17, 2010 2:04 pm wrote:
TroyVnd27 @ Fri Dec 17, 2010 12:37 pm wrote:
A good KJ/DJ does not run in bridged mode - IMO.


You said that's your opinion and you're entitled to it, but I'm curious why you would make such a blanket statement.

Is it that you don't believe a "good" KJ/DJ would ever want to run in Mono? There are certainly many environments (many of which KJs are forced to regularly play in) where stereo imaging just isn't effective. Many times with both large and small productions I've been in situations where running in mono is the best solution.

Is it that you have some believe that running an amplifier in bridged mode is bad? I'm curious what your concern is there as the impact to the amplifier really is nominal.

Just wanting to hear further explanation of why you hold the opinion you do.


Obviously, stereo sounds better. Running in mono causes your crowd to miss some of the effects intended to be heard on left and right channels. And, today, people have become so accustomed to surround sound (at home) and stereo sound (from KJs that do run in stereo mode) that they now know the difference. They might not be able to say "This guy is running in stereo and it sounds good", but they do know it sounds better and many can at least make that judgment.

Does it matter every time? No - probably not. But, competition is stiff in my area and I'll do whatever it takes to gain and maintain an advantage.

Maybe I will revise my statement to say "A good KJ/DJ will never build his system around bridge mode. Running stereo mode is almost always best, and should be done whenever possible."

I made the mistake of buying a powered mixer (for my first karaoke rig) that was mono. It sounded good, but when I upgraded to a separate mixer/amp, I was sort of embarrassed that I used to run in mono. That powered mixer is now part of my rental system I make available for DYI weddings and parties.
Author:  TroyVnd27 [ Fri Dec 17, 2010 11:33 am ]
Post subject:  Re: Help! Need a sound lesson!
and one more thing, people are also used to the new generation of jukeboxes. They sound great. If you have ever had a bar turn on a jukebox after your show, you can sometimes realize the difference in sound quality if you are running inferior equipment. And, so can everyone else in the bar.
Author:  Lonman [ Fri Dec 17, 2010 12:15 pm ]
Post subject:  Re: Help! Need a sound lesson!
TroyVnd27 @ Fri Dec 17, 2010 12:30 pm wrote:
letitrip @ Fri Dec 17, 2010 2:04 pm wrote:
TroyVnd27 @ Fri Dec 17, 2010 12:37 pm wrote:
A good KJ/DJ does not run in bridged mode - IMO.


You said that's your opinion and you're entitled to it, but I'm curious why you would make such a blanket statement.

Is it that you don't believe a "good" KJ/DJ would ever want to run in Mono? There are certainly many environments (many of which KJs are forced to regularly play in) where stereo imaging just isn't effective. Many times with both large and small productions I've been in situations where running in mono is the best solution.

Is it that you have some believe that running an amplifier in bridged mode is bad? I'm curious what your concern is there as the impact to the amplifier really is nominal.

Just wanting to hear further explanation of why you hold the opinion you do.


Obviously, stereo sounds better. Running in mono causes your crowd to miss some of the effects intended to be heard on left and right channels.

Sure stereo sounds better in the right environment. However like Tony stated, there are often times when a stereo sound can actually not sound good as everyone will not benefit from it, hearing certain instruments and not others, hearing the beginning of a drum fill but not the rest. In these situations a mono signal is the answer. Also often times in live band situation, mono is what is used. I've ran mono signals many times when stereo setup could not be acheived where everyone in the club could benefit from it.

Quote:
Does it matter every time? No - probably not. But, competition is stiff in my area and I'll do whatever it takes to gain and maintain an advantage.
Do not see it as any advatage or disadvantage, as long as a proper mix can be achieved is the goal. Stereo is not going to make or break that goal, user skills will.

Quote:
Maybe I will revise my statement to say "A good KJ/DJ will never build his system around bridge mode. Running stereo mode is almost always best, and should be done whenever possible."

When possible, again in most of the places i've worked, it wasn't possible.
Author:  Lonman [ Fri Dec 17, 2010 12:17 pm ]
Post subject:  Re: Help! Need a sound lesson!
TroyVnd27 @ Fri Dec 17, 2010 12:33 pm wrote:
and one more thing, people are also used to the new generation of jukeboxes. They sound great. If you have ever had a bar turn on a jukebox after your show, you can sometimes realize the difference in sound quality if you are running inferior equipment. And, so can everyone else in the bar.

Mono has absolutely nothing to do with inferior equipment. Sorry to say, it's mostly the user (kj) that will dictate how the night sounds. Sorry!
Author:  jerry12x [ Fri Dec 17, 2010 12:27 pm ]
Post subject:  Re: Help! Need a sound lesson!
Hmmm.
I'm not sure I'm a good enough engineer to run in stereo.
To have a person on the left hand side of the room
hear quite passages out of the right hand speaker.
I have never tried it so I don't know the implications.
Sounds a bit like you can only please the half that are in the middle of the room.
Left and right are a bit left out?
Author:  TopherM [ Fri Dec 17, 2010 12:30 pm ]
Post subject:  Re: Help! Need a sound lesson!
I actually used to use two bridged mono amps in my wedding/DJ rig but ran the overall mix in stereo. One of the RCAs in one channel, one in the other, each output from the mixer running to a separate bridged mono amp = stereo sound.

Anyway, also, like Lonman said, it is often counterproductive to run in stereo. The bar where I have my bi-weekly gig is about a 6,000 square foot square. There is an island with bar stools that runs down the middle. One side of the island has the pool tables and dart boards, the other side has the tables and bar. I set up at one end of the side with the tables and bar. So I am eccentially in the bottom left quadrant of a two-rectangle square.

On songs that have noticable stereo effects, like the beginning of YOU SHOOK ME by AC/DC, where the guitar into is panned left in the track, the whole part of my bar on the other side of the island would basically not be able to hear the guitar into if I ran in stereo. Likewise on any given track with noticable stereo effects. So I run in mono.

If you have ever seen a stereo diffusion diagram, you'd know that in any given 120 degree sound field, the stereo image is only going to intersect for about 40-60 degrees of your audience and only a comparable fraction of the depth of your bar. So for any given setup, if you are running in stereo, only about 25-50% of your audience is hearing the stereo mix at any given time. The rest are hearing some dilluted percentage of the overall track mix. That SUCKS!

This is not to mention that if you don't run your singer's monitor speaker in a bridge or mono config, then they might be missing backup vocals or even melodic instruments in their mix, which might throw them off.

So unless you have a small gig with a compact seating area, it is very counterproductive to run in stereo. Keep it mono!
Author:  letitrip [ Fri Dec 17, 2010 12:33 pm ]
Post subject:  Re: Help! Need a sound lesson!
IMO, the correct statement is a truly good KJ/DJ knows when stereo will be effective and when it will not. Case in point, a bar I used to play measured 120' x 40'. The stage was about 35 ft wide at the one end. I watched bands go in there and setup with a PA stack on either side of the stage. Only problem was that stage left about 10 ft from the front of the stage was the men's bathroom which meant a wall that protruded out about 12 feet from the side wall of the bar. Patrons could never understand why I chose to setup my stacks together, stage right and ran in mono. There were a lot of a-hah faces when I explained to them what happens with the sound from any speakers placed stage left.

I would say in at least 50% of the bars I play, stereo imaging has either no effect or a decidedly detrimental effect on fidelity. Sure, reverb effects are far more effective in stereo and many professional music tracks do take advantage of panning certain instruments to one side or the other at varying degrees. However, I can't recall any Karaoke tracks that do much stereo work and certainly vocals should always be run straight up the middle so for Karaoke especially, stereo is rarely any significant advantage. DJ'ing, I can see where if it will be effective, stereo imaging can be more important.

Keep in mind this comes from someone that would much rather work in a stereo environment than mono. However, so many times with Karaoke that is not a possibility. Even when running larger productions, I'm forced to compromise and give up on using many of my favorite "tricks".
Author:  ggardein [ Sat Dec 18, 2010 11:20 am ]
Post subject:  Re: Help! Need a sound lesson!
:) not sure I'd call that bridged(topher)......just like some power mixers using two amps(one for each channel), but not bridging from one amp.....could confuse someone.........like me..... :lol:
Author:  Keith02 [ Sat Dec 25, 2010 5:37 am ]
Post subject:  Re: Help! Need a sound lesson!
I have to agree on running Karaoke in mono as as a general rule if you are gigging.....Home setups can usually be run stereo.

What drives the decision is what others here have already stated- It's all about insuring the crowd gets the full mix, or as much of them as possible.

When running mono, you can remain very flexible and quickly adapt speaker placement to different layouts. Let's face it, many venues weren't properly designed for KJ/DJ setups....Take your typical Denneys or similar venue for example. The owner decides you must setup in some out of the way spot and often he will dictate where you stand your speaks too.....Try to obtain a stereo effect in that situation!

The ability to Bridge an amp is a godsend! I wouldn't buy a power amp that didn't have that feature.

As far as who's a REAL KJ, I'll make this blanket statement - If you are a real KJ, you will run properly crossed subs, and the subs fersure will be in mono. The best way to power subs is usually thru a properly matched amp in bridged mode(which is mono) Subs require as much as 4 times the power as your mains, so you need an amp with real guts, and seeing as how guts cost big money, then Keep it cheaper by buying a sub amp that can deliver what's required in bridged mode....Such an amp will also serve as and excellent mains back up.

Before anyone questions why I insist on subs for 'real' Kj's please consider what they do for your mains. Once you pull the sub freqs out of your mains, they brighten up bigtime and your vocals really stand out because they have less to deal with. PLUS the mains won't suffer power starvation in the horns when the sub freqs hit. If you wanna fry your horns instantly, starve them of amp headroom. The quickest way to starve horns is to run sub freqs to the woofers in the same cab off the same amp.

You will be amazed at how even a cheap set of mains perform once you pull the sub freqs out of them...You will discover they can fill more of the venue at higher SPL's, and sound more like the JBL's you always wanted.
Author:  Keith02 [ Sat Dec 25, 2010 6:11 am ]
Post subject:  Re: Help! Need a sound lesson!
Another bit of advise for OP.

You are getting a lot of great advice in this single thread. You've learned quite a bit about shopping speaks and matching amps. You have also discovered that manufacturers lie about power ratings when they only mention peak watts, or bridged watts.

But before you going running to buy speaks, there is another spec you need to compare. You want to examine and understand all about the speakers rated efficiency/sensitivity numbers.

A speakers rated efficiency is expressed in Db.....The lower the Db rating, the less efficient, the less efficient it is, the more amp required to produce desired sound pressures. It's just like shopping cars and comparing MPG. Most of us always consider MPG ratings because we demand decent efficiency from our cars today.

If you think efficiency/sensitive numbers ain't important, then listen to this: A speak rated at 96 DB, will put out TWICE the sound power per amp watt as one rated at 93 Db! that's right, for every 3 Db, the power doubles or halves.

Another way to illustrate the power/efficiency factor is to describe it like this: A 100 watt speaker rated at 93 Db efficiency requires 200 watts of amp to produce the same audio sound power as a 100 watt speaker rated at 96 Db efficiency when powered by a 100 watt amp.....Shocking, huh? Of course you don't wanna drive that 93 Db speak with 200 watts cause it will get distorted and overheat.

Now here is another neat thing about efficient speakers, not only do they require MUCH less amp, they suffer MUCH less heat damage when driven to high levels. Did you know that in the typical bargain speaker only 1 watt out of 100 actually ends up in the air as SPL(sound pressure)? Yep, the rest of that energy gets converted to heat in the voice coils of the speaker and passive crossover inside the cab. Just imagine your voice coils acting like a light bulb glowing with heat.

Now lets talk amps: Did you know it's more than ok to buy too much amp? Did you know the quickest way to fry speakers is with too little power than too much? Don't worry about overdriving your speakers with too much power, because those things have knobs that you can always turn down.....Take a look at those knobs and you will notice they are labled in Db with +'s and -'s next to them. Those aren't 'volume' knobs like on your car radio, those are input gains to the amp.....You simply note the sensitivity ratings of your speaks and set the knobs accordingly, and poof, your speakers are protected form too much power, but there is still plenty of head room for peaks.

So, please absorb all what most are saying here and get an solid understanding of all those specs before you buy. Your post was motivated by your desire to make your audio bucks go as far as possible....Ain't no salesman gonna confess all the above even if they were aware of it.

Good Luck! :)
Author:  Kevinper [ Sun Dec 26, 2010 7:57 pm ]
Post subject:  Re: Help! Need a sound lesson!
Quote:
.....Take a look at those knobs and you will notice they are labled in Db with +'s and -'s next to them. Those aren't 'volume' knobs like on your car radio, those are input gains to the amp.....You simply note the sensitivity ratings of your speaks and set the knobs accordingly, and poof, your speakers are protected form too much power, but there is still plenty of head room for peaks.


We have a Yamaha P5000S amp and 2 C115V speakers. I really have no clue what you mean by noting the sensitivity ratings and then adjusting accordingly. The sensitivity rating for the speakers are 99dB SPL (1W, 1m) <----no clue what that means either.

The "Volume knobs" go from 00 to 40, 30, 25, 20 ,15, 10, 6, 3, 0 using 31 steps. Where would I set the knobs for my speakers?

I started out knowing nothing when we started karaoke over two years ago and still know most of it.

Thanks for your help.
Author:  Keith02 [ Sun Dec 26, 2010 8:50 pm ]
Post subject:  Re: Help! Need a sound lesson!
I ain't familar with your speaks and amp, and I ain't gonna look up all the specs, but try this

Crank the amp down....now trim all your strips for proper input gain using pfl, then raise channel sliders to unity and trim the master levels just short of clipping.....from there bring up mains with amp input gains until house spls are at max you expect to use-but watch amp clip lights as you do this...if you see amp clip lights flicker, then back off a click......that is where the amp gains must stay and that is the max spls you are going to get for that venue.

Now go back and trim channel sliders for proper mix, then use masters thru show to control 'volume'

All the above applies only if you have properly matched your speaks to the amps.

If you have fatter amps than speaks, then do all the above wile carefully listening to each cab for distortion and back off amp input gains to protect them

If you are crossing cabs off same amp, then attenuate horns channel as required using peak ratings of horns and continous ratings of woofers.

I guess a better explaination of those input knobs on your amps is that they set the point where your amp will hit full power......the knobs set/limit input sensitivity....by cranking knobs down you make the amp less responsive to input from mixer.......The amp can still hit full power, but usually only if you clip upstream of the amp.
Author:  Kevinper [ Mon Dec 27, 2010 11:23 am ]
Post subject:  Re: Help! Need a sound lesson!
Deleted 'cause it sounded mean.
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