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| Thread ID: 49607 | 2004-09-25 01:54:00 | Computer Problem Diagnoses | Nighthawk (5846) | Press F1 |
| Post ID | Timestamp | Content | User | ||
| 275501 | 2004-09-28 02:11:00 | > meh Metla is stirring Yeah,by handing out some needed advice,i am obviously pure evil. Perhaps you would care to explain your leap into pure stupidity that bought about such a comment? |
metla (154) | ||
| 275502 | 2004-09-28 02:20:00 | There was a long thread ( . pcworld . co . nz/thread . jsp?forum=1&thread=33786&message=152099&q=pmpo#152099" target="_blank">pressf1 . pcworld . co . nz) on this some time ago . To save you going back through that thread if you don't feel like it, the following is as much as you need to know about PMPO values . They bear no relationship whatsoever to reality, being advertising puffery of the worst kind . Quote: "Peak Music Power Output (P . M . P . O . ) is the combined output power of all channels of an amplifier measured by the highest decibel level an amplified signal reaches at any point of time . In short it is the total music power output an amplifier is rated to produce . " So to get a more realistic idea of what these power outputs mean for a two speaker system, the first thing you do is divide by two to get a rating for one speaker . Now 650 watts becomes 325 watts PMPO per speaker . Next we have to consider that this is (supposedly) a measurement of sound output level which we don't actually measure in watts at all, we measure this as sound pressure level or SPL and it is measured as an instantaneous db peak . This is not actual music, this is one transient splot in time, and unfortunately this takes no account of distortion effects . Trying to get a grasp on this to make sense of it all, we can reduce that 325 watt peak to RMS by multiplying by . 707, which gives us 230 watts . Now, cheap audio these days is a modular design sort of thing and the integrated circuits that power these speakers are often used in battery powered portable equipment as well, so most small amplifiers run a power rail of around 12 volts . To get 230 watts per channel RMS of audio output from a 12 volt supply you need about 25+ amps of input current per channel . (If you don't believe this, take a look at the connectors and cable sizes for a serious car audio system, and while you are about it, ask yourself why it is that car audio systems are never given PMPO ratings . ) This level of current is simply not available from the tiny power supply supplied with the speakers, not even as an instantaneous peak, so at this point we must divide that 230 watts by the designer's hat size (say 6) multiplied by his shoe size (8) and we get just a little over 5 watts . Back the volume down to a level where distortion is bearable and now we are running about 3 . 5 watts rms per channel . This final figure is pretty much for real folks, except that I had to guess the hat and shoe sizes . However, if the designers are halfway honest RMS output can be as high as 10% of PMPO but there is no mathematical correlation because once again, hat and shoe sizes are unknown . Using this formula, 650W PMPO is about 65W RMS . Divide this by two for the per channel rating and we have around 30 watts per channel . Bring the distortion down to acceptable levels and you can expect about 15-20 watts RMS per channel into a quality set of speakers . This can be achievable in mains powered equipment, but is way beyond the capacity of portable battery powered gear unless you own a farm of battery hens that lay sealed lead-acid eggs . The answer to all of this is quite simple really: Favourite music + typical listening environment + listening test + satisfaction with volume levels and sound quality = Purchase decision . No other formula can guarantee satisfaction . Cheers Billy 8-{) |
Billy T (70) | ||
| 275503 | 2004-09-28 03:15:00 | uh!! this is starting to sound like maths so i wonder why the speakers barely work if they dont need 240W they crackel, die out, only 1 works, have to turn them on and off to get it going.. very unreliable nevertheless i must ring a computer shop now about psu quotes |
Nighthawk (5846) | ||
| 275504 | 2004-09-28 04:48:00 | > they crackel, die out, only 1 works, have to turn > them on and off to get it going.. very unreliable Crappy speakers, poor connections, or internal connection fault. You are doing a lot of dough here by not pursuing your warranty. The power supply was clearly inadequate and should be replaced free, and your speakers should be repalced as well. I wish I had that much money to waste. :( Cheers Billy 8-{) |
Billy T (70) | ||
| 275505 | 2004-09-28 05:13:00 | Remember that figures in advertising material are frequently presented with the sole aim of selling stuff that would not stand a direct comparison with competitors. As Mark Twain remarked, "There's lies, dammed lies, then statistics". way after this comes advertising data, which rates as less reliable than a pre-election promise. Some one else said "There's nothing in this world that some man cannot make a little (or a lot) worse and sell a little (or a lot) cheaper and those who consider price alone are this man's lawful prey". For power supplies, speakers, graphics cards - there are 3 criteria: Performance, Durability, Price. Pick any two. I would be tempted personally to divert a bit of effort to ensuring that E One live up to their obligations, after all, it was real money you gave them. Don't reward them for passing off crap unless you enjoy being a sucker for them. /rant R2 |
R2x1 (4628) | ||
| 275506 | 2004-09-28 05:29:00 | > hello, according to KZCS my cpu (AMD 2500+ barton) > needs minimum 350W to run properly!! so its > definitely a power supply muck up Their talking out a hole in their ass, theres no way you can reckonmend a PSU based on the CPU. Stop trying to save money, if your going to buy a new PSU buy a decent one. Theres no point in replacing a Lada with a Lada. Hyena, Task, Deer and many others make crap PSU's. Just because it says 500w on the side doesnt make it a good PSU. A 300w Enermex would kick the pants off a 500w Hyena. If your looking for a affordable PSU have a look at 420w Thermaltake or a 300w Enermex, both are good PSU's and will power you PC easy. You could always just replace the fan thats making the noise? Fans are dirt cheap and its not exactly a science to replace one. Why are you trying to play DOOM3 on a 9200? The 9200 barely counts as a entry level card let alone a gaming card. The card is probably overheating or needs to have its drivers updated. Ive never tryed DOOM3 on a 9200 it wouldnt surprise me if it refused to play the game full stop. Sounds like your speakers are a pile of crap and have just crapped out. Thats what happens you buy cheap products. |
Pete O'Neil (250) | ||
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