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stealthaxe wrote:
"Timothy A. Seufert" wrote in : I'd sure not trust a $ 10 DVM to give me readable levels on a quickly varying signal. That's very hit-or-miss. Ears are probably better. $10 DVMs can and do have AC measurement features. There is no reason why they can't be accurate enough to outdo ears, which are not very accurate at all. Please name one $ 10 DVM with true RMS true and peak hold or integration function. You missed the point entirely. When you are matching levels, you are feeding the same test signal into the speaker terminals. All you are trying to do is to have the readings be within 0.1 dB or so of each other, using basically the same test stimulus. You do not need a rms function, and you do not need very good frequency response from the DVM. For instance, when you are to match a CD player's output level to another, you play a test disc with sinewave tones. Let's use 1 KHz. You use the $10 DVM to make sure that the measured levels are within 0.1 dB (about 1%) of each other. The DVM may be off by 3 dB in terms of *absolute* accuracy, but it does not matter because you are comparing one reading vs. the other. All you need from it is to have enough resolution, and be able to respond to the 1 KHz tone without too much roll-off. You can also use 100 Hz tones when you are comparing CD players. The rest of your post is not relevant in the context of matching levels. We are not trying to measure exactly the absolute voltage levels at the output terminals. We are trying to make a *relative* measurement using the same stimulus. |
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