Dbw
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Bronze Member Username: Daniel_canadaCanada Post Number: 63 Registered: May-06 | I copy and pasted this from Musical Fidelity's web site. I understand what it's about, anyone else want to comment? I'm bored at work, slow summer day here. "............ Why amplifier power is important For Musical Fidelity, one of the markers of genuine hi-fi is a decent dynamic range. To produce a decent dynamic range, the system needs to be able to produce peaks of at least 100dB in your listening position, and comfortable peaks of 105dB to 110dB are better. However, 100dB is the bare minimum requirement, and any system that produces less than this does not deserve the name of hi-fi. It takes an amplifier with a lot of power to produce peaks of 100dB or more. Many amplifier manufacturers produce units with low power and call them 'high-end.' Low-power amplifiers will produce a surprising continuous level, but unless they are coupled with extremely efficient loudspeakers, they cannot possibly produce a decent dynamic range. No matter what a manufacturer says, or how much it costs, a low-power amplifier is not genuine hi-fi. Unless you understand the relationship between amplifier power and peak listening level, which most audiophiles do not, you are likely to be sold something that costs you a lot but is not really a proper hi-fi system. One reason that few audiophiles understand the relationship between amplifier power and peak listening level is that loudspeakers and amplifiers are specified differently and there is no obvious way to use the information to find out what kind of peak levels you can expect from a particular system. Most manufacturers are loathe to clear up the confusion, for reasons that will become clear. Loudspeakers are usually specified by their efficiency; they produce a certain number of dB for 1W at one metre. However, as you move away from the loud- speaker, you lose about 5dB for each metre over one metre. You'll see in a minute why you need to know this. Amplifiers are usually specified by their power rating in watts. To use these two pieces of information, you need one more number - the amplifier's power in dBW This is a measure of how much sound (dB) is produced for a certain amount of power (W). As you will notice on the table, the amount of power needed for each increase is not linear - each increase in dBW requires a steep increase in power. A low- powered amp will never be anything other than a low-powered amp: we are dealing here with the laws of physics. However, armed with this information, you are now in a position to find out whether or not your system is capable of peaks of 100dB or more. To find out what a system can do, take the loudspeaker's efficiency, add on the amplifier power in dBW and deduct for the listening position. You have now worked out the system's peak level capability. For example, to work this out for a system with loudspeakers of 87dB efficiency and an amplifier power of 200W and a listening position about three metres from the loudspeaker: 87 + 23 - 10 = 100 dB peak level capacity. This assumes that the amplifier's power really doubles into 4 Ohms, a can of worms that we will not open at the moment, and that the amplifier is stable. In this example, the system would be just about reasonable...." |
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Gold Member Username: NuckPost Number: 3026 Registered: Dec-04 | Hogwash. |
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Bronze Member Username: Daniel_canadaCanada Post Number: 64 Registered: May-06 | ROFL, love it. The boys (and girls) at MF seem to like what they have to say. But the MF gear does sound "nice". |
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Gold Member Username: NuckPost Number: 3027 Registered: Dec-04 | Yes, it sure can, Dan. I like 100db as much as the next guy, but as a qualifier for Anything? Haha. Embarassing for a good product. Now as far as doubling output at 1/2 impedence, that I pay attention to. |
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Bronze Member Username: Daniel_canadaCanada Post Number: 65 Registered: May-06 | Nuck, you are too funny.  |
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Bronze Member Username: Daniel_canadaCanada Post Number: 66 Registered: May-06 | The only comment that rubs the wroung way is "No matter what a manufacturer says, or how much it costs, a low-power amplifier is not genuine hi-fi." Bullshit. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 3399 Registered: Feb-05 | Listened to my 40 watt per channel PL2 next to an MF A3.5 and found the MF wanting. I could have bought either....the MF is still sitting on the shelf at the "HI-FI" store. |
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Gold Member Username: NuckPost Number: 3029 Registered: Dec-04 | A couple of 5watt SET's might have something to play about that. HiFi and high volume do not necessarily share the same bong. |
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Gold Member Username: ArtkAlbany, Oregon USA Post Number: 3400 Registered: Feb-05 | Huka perhaps.... |
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Gold Member Username: NuckPost Number: 3032 Registered: Dec-04 | hehe. I say not necessarily, but there are many examples of commonality, some of which I have investigated lately. How HI-FI and how much power are quite variable. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8701 Registered: May-04 | http://www.myhometheater.homestead.com/splcalculator.html |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8702 Registered: May-04 | The MF site forgoes the additional gain of a stereo pair of speakers and the room gain. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8703 Registered: May-04 | dBw was introduced to the consumer by High Fidelity magazine back in the early 1970's. |
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Bronze Member Username: Daniel_canadaCanada Post Number: 68 Registered: May-06 | When did SPL convert to quality? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8704 Registered: May-04 | There is no definite time for that occurrence. Some people would say it happened when AR brought out the first acoustic suspension loudspeaker. Others would tell you it happened when TI created the transistor. Still others would tell you it happens when your hormones first begin to rage, somewhere around age 11-12. Obviously there is no correlation between SPL and quality. The 100dB mark mentioned in the article represents what is assumed to be the loudness potential required to recreate a live performance with "accuracy". |
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New member Username: SariusPost Number: 7 Registered: May-06 | Good read, thanks Jan, This is all basic physics. Obviously they're talking about the ability to accurately reproduce uncompressed dynamic transients, NOT just the ability to play 'loud', which of course, takes considerably less power. There is simply no getting around the inverse square law, so if you're twice as far away from your speakers they've got to have four times the acoustic output in order to have the same apparent volume. There is also no getting around the fact that you need to double amp power to get 3 DB more dynamic range. The rest, is as they say, simple arithmetic. As the old saying goes: Physics- not just a good idea..........IT'S THE LAW!! |
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Bronze Member Username: Daniel_canadaCanada Post Number: 77 Registered: May-06 | Yes, the inverse square law. The square root of 2 I beleive. Like a camera lens, to double the exposure open up one f-stop. One f-stop = square of 2 (1.414...) Damn, is it slow here today. |
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Gold Member Username: NuckPost Number: 3039 Registered: Dec-04 | Dan, it may be slow, but y'all ain't. Bel, I never studied law. |
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Gold Member Username: NuckPost Number: 3045 Registered: Dec-04 | So I plugged in and got 108db. So I'm HI-FI now? Pardon me? |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 8708 Registered: May-04 | We'll grant you're "Hi", and hold our opinions regarding "Fi". |
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Silver Member Username: DakulisSpokane, Washington United States Post Number: 957 Registered: May-05 | IS dBw the same as IQ, I plugged mine in and got about 101, sounds too high to me. LOL |
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Gold Member Username: NuckPost Number: 3055 Registered: Dec-04 | Ba-dump bump. Somehow the max capacity formula involves entering the amp's max power before clipping. How, precisely would one measure that? Seems to me you would need Db meter and a tape measure, an aligning tool and steadfastness. Even then, you would determine only the amp's power for any given track, etc. What about the levels usually used, like 80-90Db? Yes the ferrari goes 320 kph, and yes I drive 115.(type of thing). |
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Bronze Member Username: Daniel_canadaCanada Post Number: 79 Registered: May-06 | Damn, i got 114. I really must be hi-fi. Yes I'm da pwn. lol |
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New member Username: More1707Post Number: 1 Registered: May-06 | dish down key for pansat 2700A? thanks |
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Gold Member Username: NuckPost Number: 3061 Registered: Dec-04 | wrong place. You're welcome. |
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