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My latest dilema with some fried speakers has left me "jittery"

Looking at replacing some speakers and possibly an amp.  Need to understand AGAIN the numbers  and what they mean - Let's talk 15 "speakers for now

A) YAMAHA BR15 - 250W PROGRAM  / 500W PEAK  / 98DB SENSITIVY
B) YAMAHA S115V- 500W PROGRAM  / 1000W PEAK /99DB SENSITIVITY
C) BEHRINGER B1520 - 400W PROGRAM  / 800W PEAK / 96DB SENSITIVITY


Which speakers would be best matched with my amp
Crown XLS602D 380W per chan @ 8ohms

What numbers do I look at to match amps with speakers ?
Is it best to buy MORE power than required ?or the same - IE: a 400watt amp for 400 watt speakers ?    Whats the sensitivy and do I need to look at it ?
Forget MAKE AND QUALITY of the speakers mentioned just interested in the NUBERS and how they stack up

Just based on the numbers (and a bit on the brand) the Yamaha S115V sounds like the best match.  The "Sensitivity" specification measures a loudspeakers ability to create a high decible sound with a low input, generally measured by applying 1 watt of power to the speaker and measure the decible level at a distance of 1 meter from the speaker.  It is generally a measurement of the speakers "efficiency" or the ability to produce a significant sound level from a low level or modest input from an amp.  Those numbers seem kind of high, but certainly adequate.  

The Yamaha Spec's should be up to par and they're definitely a reliable and trusted manufacture.

Not sure if you'd go for an open box deal but I found one online for $199 each
http://www.audiolines.com/Yamaha-S115V-p-6510.html

If you're checking out that website DEFINITELY give them a call and get all the specifics, I'm not a customer of theirs, I did a web search and that price popped
right out at me.  Make sure you get some form of warranty in other words.

A lot of companies, even the more popular ones, take advantage of specification
standards, at least Yamaha fills you in on the "Program" vs "Peak" power handling, when I purchased Mackie 500's a few years ago, even on the Mackie web site they were listed at 500 Watts Period, upon arrival I saw right on the speakers input panel 250 Watts program, , both those low end speakers have been blown, now they're Carvins.

If I'm not mistaken, you're the guy that tried to help out some young girls at the end of the night by cueing up some hip hop and the bass over-powered your speakers.  Don't worry, it's happened to all of us, just bear in mind what happened the last time and pay close attention to your levels at ALL times, especially the bass or low end on those hip hop recordings.   Start low when setting your levels and work your way up, don't expect your speakers to do something they're not designed to do and you should be fine with those Yamaha 15's, I think you posted that your last pair were 12-inch low end, the 15's will make a world of difference.

Good Luck

Out of the 3 the S115 is going to be the loudest with the same amount of power applied.
You should still try to match the program rating with the equivalent amp power.  Alot of people make the mistake 250 watt speaker (RMS) & get an amp that pushes 250 watts.  The speakers program rating is at 500 watts.  What happens is the amp is going right along, pushing it's rated power, then all of a sudden you need to turn up the volume.  Well now the rated power is done & it starts pushing into clipping - distorted signal, you may not even notice it at first.
If the amp you had was rated to push the program power, same scenerio, you are only pushing 250 watts, but now you need to turn up, you are still pushing within the amps clean signal & not driving into clipping.
The Crown amp is not the best match for the S115, better match for the Behringer, but you would need to turn up the speaker louder to get the same volume - possibly putting you into the distortion scenerio again.  It's over power for the BR series.

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When matching speakers and amplifers I have always had approximatly 25% more power than needed for a main speaker not a subwoofer.

My current speakers are 600 watts program. I feed them with 700 watts, I never clip I use the clip limiters on my amp but I never come close to clipping on my mains.

All speakers are tested under different variences. Unless you truely know the speakers, the RMS rating is what you want to power the speaker. So give yourself 25% of head room over the RMS rating.

You can also go by the manufactures suggested amplifer.


Sensitivity.
3db in difference is percived as 2x as loub by the human ear.

The Yamaha S115v says it's max spl is 129db but with a sensitivity of 99db it would take 1536 watts put into this speaker to achive such a level. the reccomend 500 watts will produce 124 db.

The Yamaha BR 15 will max at 121db at 250 watts

The Behringer will max at 120.5 db at 400 watts

So this being said the Behringer is extrenly inefficent. The S115V required 2x as much power as the BR15 but will be 2x as loud.

What isn't taken into factor is the ability to produce even frequency. With that in consideration. You need to take 2 or 3 speakers at fit your application and listen to them with a flat eq setting.

Let's stick with the Yamaha SI15V for a moment - With a bigger amp:
Crown XLS802D  - 500w  per chan @ 8ohms
Behringer EP2500 -450w per chan @ 8ohms
This is MORE of an ideal set up ?

What is the "CONTINUOUS " RATING  versus program like below on the JBL
JBL JRX115 15" 2-Way Speaker Cabinet - Pair Specifications:

Frequency range (-10dB): 38Hz - 16kHz
Frequency response (±3dB): 50Hz - 12.5kHz
Sensitivity (1w/1m): 98dB SPL
Nominal impedance: 8ohms
Power capacity: 250W continuous, 1000W peak
Maximum SPL: 120dB
Nominal dispersion: 90 degree x 50 degree
Crossover frequency: 1.6kHz

Those S115V are some of the best inexpensive speakers out there IMO. You have to decide if you want to lug those heavy beasts around. I got my EV SX100 because they only weigh about 30lbs. each. I'm thinking about getting a pair of the S115V because I love their sound. I won't get rid of my SX100 though.

Yes those amps would be more suited match for the S115's.
On the JBL, the continuous (RMS) is 250/Program would be 500/Peak is 1000.  If you notice in most manus ratings program is double continuous & peak is double program - as a rule.

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Great Question with Great Answers ,hats off and thank yous to the responders, thats the beauty of this forum you can actually Learn things here as i have. I'm going to print this post and show it to 99% percent of the folks who run karaoke in pgh PA with 200 watt powered mixers pushing yamaha S115s. I'ts simply not enough power at loud volumes which becomes a distorted mess. I get dissapointed and leave their shows and go home and sing. I also have 4 yamaha S115s that i push with a Carvin 2570 Amp 700 watts per channel into 8 ohms, plenty of power, headroom and clarity, i have never seen the clip light come on, i don't even know what color it is!

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My original 1st ever set up consisted of Peavey SP5G - They were awesome speakers but F'in Heavy to lug in and out every week. ( for the small venues I was playing) - In addition to them a few years ago I picked up some Yamaha S115IV -
They sounded just as good as  the Peaveys were a tad lighter and not as bulky.
A few months ago I turned over some speakers and sold those 4 for the Behringers  - I bought 2 12" liteweights B212 - That due to my error ..fried them
I still think they were Good speakers for SMALL JOBS.   The B1520 Behrigers are a Good speaker ..but admittedly not as GREAT as the Yamahas or Peaveys were.  

My idea is to leave the BEHRINGER B1520's at my Saturday Gig with my Powered Mixer.  I WAS running 1 side of the amp to the 2 speakers daisy chained together.
Now I'm questioning if that is OK?    Amp is rated at 2 x 400watts @4ohms  - Speakers are 400w program at 8ohms ?   I understand once daisy chained the speakers are now running at 4ohms.  ---so I have 400watts going into 2 speakers
GOOD  / BAD / DANGEROUS ?????

Now IF that set up is OK .....then I can start rebuilding my BIGGER set up  :D

It isn't ideal by any means. If you can restrain yourself on the gain it will work, but you can't have those hip-hoppers back.

I have run B1520s on a powered mixer with similar specs (PMH3000). But I use my EP2500 to drive those nowadays, and I usually have my wife with me to ensure the volume doesn't go too high.

OK--Let's try this set up ----

My Behringer PM880S Powered Mixer - 2 x 400watts @4ohms
2 Yamaha BR15 or similiar rated speakers

Behringer offers another speaker E1520 rated at 200w program @8ohms
Would this be a better MATCH for the Powered Mixer.

(I want to use the powered mixer as I can LEAVE it at the bar and share with the other DJ, It takes up LITTLE space and is super light. ) I have been using with the LARGER speakers but don't want to take any MORE risks.

In a small to medium venue - Is there a noticeable differance in using a perfectly matched set up - 1 at 200watt  / 1 at 400watts- as far as volume ?  Sound Quality?

Only your ear can tell that. The sound quality is what it is. Power mismatch is only a problem when you are driving the amp really hard*, and if you simply don't do that you should have no problem.

If your gain structure is reasonable, in the 0dB range, and you don't peg the mains output control, I am guessing you will be fine. I was with the PMH3000. But if you are riding in the +dB range on the faders and have your channel trims set high, watch out.

* Or not supplying enough power to drive at all, of course.

If the speakers individual rating is 400 watts program at 8 ohms, when you tie 2 together in parallel, they are now 4 ohms & would bump their program rating to 800 watts.  The 400 watts at 4 ohms the amp pushes, is still half of what it should push for the speakers.

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That would be a better combo.  If you tied both speakers together, the 4 ohm load program power rating would be 500 watts needed.  Still underpowered but closer.



May be a better match but far from an upgrade.



More power is always going to sound cleaner & fuller than less - you send a speaker a nice clean signal that's what it is going to reproduce, you send a speaker an amp signal that is on the verge of distortion, then that is what it will reproduce - turn the last amp up anymore, & you are sending more distortion.  The 200 watts may not make a huge difference as far as volume, but if you ever needed to turn the volume up (i've had to turn up pretty dang loud in some small bars) - you'll be running into the same problem you did when your woofs blew.

Wrong eq'ing can also help blow a speaker - too little bass, you turn your eq up to compensate, well those bass frequencies are pretty power hungry & can push your amp to or past it's rated power pretty quick - clipping.
Improperly set-up prcessors like the BBE or Apex that add bass & subharmonics - same thing.  Be careful with these as well.

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My understanding is that as long as the wave form is OK, it doesn't matter. In other words, if you are operating in the normal range of the amplifier, essentially you won't be able to distinguish the difference in the output of two amps at a given power level.



This all I am on board with. The key is not to push things too hard. If your venue is like most of mine, where you never get large enough crowds to cause you to really jack up the power, then there is no problem. But when you are wall-to-wall people, you need the power. Luckily, if you are drawing the kind of crowds that need that power, you should be getting paid well enough to justify the amp.

While from a technical standpoint that may be true, but if you were listening to a low power amp & a high power amp side by side at the same volume, you would most likely be able to distinguish which was which at the same volume level - and definitely would notice the difference at higher levels as the higher powered amp would be able to push the frequency range with more consistancy that the lower powered amp would start showing signs of fatigue in the lower end to start with & even the higher end, lower volume levels maybe not so much of a difference but then nothing is being driven to clipping yet.  But chances are in real world scenerios, the chance of turning your system up is going to outweigh listening at lower volume levels.  It's just best overall to have a little headroom, than none at all.    

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The Saturday Gig is SMALL  bar - rarley wall to wall people and in all the years I've been there never had problems with any set ups.  It was this last time trying to push the lightweight 12" to do the job of a 60lb- 15" main which caused the problems.

I have in the past been running the powered mixer with the Behringers without any problems.  The sound was crisp, clear and loud enough.  - Now that I have a 2nd steady gig which is LARGER  / YOUNGER  / BUSIER  / MORE CROWDED?......I was hoping to take the EP1520 Behringers and use THEIR.

After all the talks --I believe I am leaning towards getting a 2nd set of Behringer B1520 as they are a better match for my current amp Crown XLS602D.  This way I think leaves me with the best matched choices without buying a new amp. (maybe in the future).  I am also looking into removing the single cdg player from my rack and putting in a compressor/limiter for the mics to start - this will give me needed protection.  I have on back order 2 Peavey PR15 to use for small DJ type gigs and as temporary back ups in the event of emergency.  wheeeew

Thank you ALL for your thougts and expertise !

Sound like a PLAN.

In simple terms All amps have three components.

A current sourxe  
Tube cathode
Transistor emitter
\
A collector
Tube plate
Tansistor collecter

A control point in which a small input causes a large output (amplification)
Tube control grid
Transistor base

Ok let's say you have a single stage transistor voltage amp with a gain of 10/1. The power supply voltage is 12 volts. About 2 volts would be used for biasing requirements.
The base is biased at 5 volts and theoreticaaly we can have a voltage swing of positive 5 volts to - 5 volts. A .5 volt positive and negative input on the base will result in a 5 volt psitive and negative swing on the collector 10/1 gain. This is in the middle of the linear portion of amplication for that particular transistor.  It is impossible to input a 1 volt peak to peak and get a full swing of 10 volts swing out. That is because it is at the extremities and a portion of the transistor is not a gain of 10/1 The result is distortion.

If the input exceeds 1 volt peak to peak the collector current is saturated (the power supply capabilitity is exceeded) and the result is the upper portion of the signal pos and neg is flat lined. This is audio clipping. The duration of this DC component is relative to frequency and at bass freqs it is longer.

Now this stage might be feeding a next stage or maybe it is the the output of an amp driving a speaker. A basic fact MAXIMUM POWER TRANSFER OCCURS WHEN THE IMPEDANCE OF THE LOAD EQUALS THE IMPEDANCE OF THE SOURCE. In the case where a 100 watt amp is driving a 300 watt speaker when the the amp exceeds 100 watts due to the current demand of the speaker the amp output current is saturated and clipping results.  In the case where a 300 watt amp is driving a 100 watt speaker the excessive current above 100 watts overheats the speaker coil and shorts windings just the same as under powering.
)

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I definitely agree with the desirability of having the headroom. Now that I do, I think I can tell the difference at higher volume levels, but I really can't at the lower ones, which seem to sound the same.

Any machine is most efficient at the middle of its operating range whether mechanicl or electrical AT the extremes the temperature rises reduces the overall efficiency

The current of the ouput stage is determined by the signal input At mid range the temp is normal AS the signal is increased the current increases and the temp increases. It is common sense.

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