There are a few guides on eBay about Audio Equipment that are not really accurate, but never the less the main point has been clearly put accross that MAX - PEAK POWER - PMPO Speaker power ratings should be ignored (So should amplifier ratings in this manner)

The rating you need to be intrested in is the RMS value (Root Means Squared) the Max, Peak, Music Power, PMPO ratings are not illegal or missleading if you understand that they are just different ways of measuring a products ability. One guide claims that if you buy a 300W RMS speaker you can run it at 300W all the time, this is not correct. There are many factors to consider, one is that the RMS figure is claimed by each manufacture under Lab Testing, but its deeper than this as you can have 2 speakers both rated at 300W RMS but one will sustain more punishment than the other, one may distort sooner. The ratings are achieved by sending a White or Pink noise through the speaker for a set period of time, this time can vary and also so can the frequency of this. A pink or white noise sounds like a FM radio thats not tuned in, that hissing sound, this basically has a rather flat curve to it if you look at its signal, where as live or recorded playback music signals are nothing like this what so ever. The bass is the most demanding signal, and if you add bass using a bass control on a mixer or amp you are increasing this signal and the amplifier basically amplicates a what is already distorted signal as the curves are choped off as the signal is too large, this means that even at 50W RMS output your 300W RMS speaker will distort.

As you can see there is more to all the MAX, PEAK, RMS talk than one can imagine, if you buy a pair of speakers off eBay say 300W max Each yes they are probably 150W RMS, but even expensive brands would struggle to produce this constant, you have to consider many other factors, amplificaction can  be better if the amp is more powerfull than speakers, but care must be taken, a 1000W RMS bass driver will distort at 400W on a 400W amp as the amp has reached its limits so basically you need to look at purchasing double the power you think you need. People rant and rave about 500 people in hall or 150 people you need this much power, that much power, its nonsense. If you have a good quality 200W x 200W RMS PA System, and the SPL (SOUND PREASURE LEVEL) is good, for example you can have two speakers both 300W Rms for example one speaker can be 89db @ 1W / 1M and another is 98db 1W / 1M the 98db speaker although same power actually sounds a lot louder, and it is as its more effecient, its the same as car engines, both can be 3.2ltr V6 engines, one is 185 BHP and the other 245 BHP.

One other thing to remember is that you can blow a 1000W Rms speaker with a 300W Rms amplifier if you allow it to constantly clip, run distorted for a loing period, DC current can be placed down the speaker, there are so many factors to consider, so it pays to purchase or consider purchasing from those sellers on eBay who are actually in the bussiness, and not someone who is selling from there bedroom, they can be very missleading, we have seen many listings that make us cringe, for example one eBay seller (Private Seller) was selling a PA system 1000W the amp was 500x500 and speakers where 500W x 500W but the speakers where 8 Ohms and so the amplifier (if you look at the spec) will only produce around 350 x350w rms with an 8 ohm load, so if you buy a 1000W rms amp total output (this will be rated at 4 ohms more expensive amps rate 2 Ohms, but we do not advise running amps this way) you need 4 x 8 ohms speaker cabinets to get your full output from your amp. Remember good quality speaker cable and connectors, good audio leads to the amplifier for your sound source.

Below is some tips on how to have a good sound system:

1- Use stands for Full range cabinets and get above audience head, this will save your amplifier and speakers working so hard.

2- Use an active crossover and 2 amps, one for Bass and one for Mid/Top, spliting the signal before amplification is far better, and in addition your Bass Speakers and amp only have to deal with the Bass notes, this is the same for the Mid/Top cabs and amplifier, basically the Mid/Top cabinets speaker driver does not have to pound in and out and whilst doing this try and reproduce a long vocal note, have you heard that gargle sound when your pushing your speakers too hard? thats because the cone is fully excurted and can return fully as a mid frequency now whats to come though, then the next bass line comes along and the cone is not where it should be so constantly excurted.

3- Set your bass/treble to 12 o'clock or Flat when you add bass and treble your adding more power to the amplifier & speakers and at high levels they will just distort.

4- Keep speakers in a dry warm room, cold and moisture can have serious effects on certain types of cones, brands etc.

5- Above all purchase using the RMS figure for amplifier and speakers and as genral rule keep them the same, this way your have headroom if you run 1 pair (8 ohm load) or 2 pairs (4 ohm load) also remember to be carefull as you can get 4 ohm and 16 ohm cabs, running 2 pairs of 4 ohms cabs could take your amplifier below its stated impedance and cause to overheat or damage it permantly as your loading it too much.

REMEMBER if in doubt speak to the profesionals, we have articals on our website, and if you choose to deal with the professional sellers on eBay you should get correct information, but make sure your not being sold somthing they have had on the shelf for too long, if they are professional, they will ask you for as much info as possible to build up a picture of your needs, and you should always give them an idea of your budget, as this really helps to decide whats best for the customer, sometimes and extra £25 can be well spent so prepare to be a little flexible, and remember although eBay is full of bargains and you can save a lot over shop prices, check its new goods your purchasing, not B Grade or customer returns, and check has warranty, and remember Price is not always the important thing here, someone selling on eBay simply undercutting the professionals may well not be around to pick up the peices if something did go wrong with your product. Customer service is an important factor too.

Hope this helps!

netricals