|   Technical specs | musica
Dec 5, 2002 11:04 PM | | Why people often say that technical specs of speakers (and sometimes of amplifiers/receivers as well) are worthless?. Are there real reasons to state it?. |
| re: Technical specs | CHRIS8
Dec 6, 2002 2:58 AM | | I will focus on speakers, since this is the relevant forum :)
Specifications, as published my manufacturers, are generally worthless.
Now, measurements are valuabe! At least, when engineering. Of course, the set of meausurement used for refereence/design are only of specific use in given circumstance, to aid in design. It is theoretically possible to even predict very accurately, how a speaker will react in given environment, and how it should 'sound'. Afterall, the only things involved are essentially sound pressure vs. time vs. spatial planes. These things can be measured very accurately. However, the sets of measurments, how they are obtained, in what environment as well as knowing the exact conditions of the end user environment, and specific methods used to record and process the source material, and the reactivity with the end user amplifier are beyond the scope and capability of any practical application for general reference. So, what we have published about products(and even by diy speaker builders)are a very limited number of measurements examing very specific areas of performance, but not taking into account the vast number of variables that would have to be calculated(nor could they in practical situations.,e.g, other than a controlled labratory setting)in order to simulate teh end effect.
The limited measurements such as on axis frequency response, THD(some more expensive speakers publish this), power handling have very limited meaning. ANd, with the consitent differing methods/standards used by different manufacturers....most of the this is not even reliable. The only specfication i know of that is usually accurate on speakers is the weight and color specificatins. :)
The most valuable speaker measurments i know of in a database, are the ones published in stereophile every months. While they certainly can not tell you what a speaker will sound like, they are very telling of certain characteristics which are of limited use to people have a point of reference. The specific measurements i find most useful in stereophile are the lateral response charts and the waterfall. The first to give me some idea of power response and the latter to indicate problem areas of stored/delayed energy. I find these useful(to a very limited degree) when i wish to audition a new product. I wish they would expand to a THD and high resolution impedance of the drivers without the crossovers connected. The latter allows you to weed out for the most part, which resonances in the waterfall are genuine, and which are spurios reflections/hash.
-Chris |
| what about sensitivity? | mlowie
Dec 6, 2002 9:22 AM | | " The only specfication i know of that is usually accurate on speakers is the weight and color specificatins. :) "
Aren't most,if not all efficiency ratings measured in db at a distance of 1 meter given 1 watt of power? Surely the efficiency is not only an accurate measure, but also important to the end user. |
| I agree. You may now beat me with bamboo for my oversite. (nt) | CHRIS8
Dec 6, 2002 10:51 AM | | (nt) |
| re: Technical specs | Ray from RI
Dec 6, 2002 9:22 AM | | They are not ALL worthless. Before I buy a speaker, I'd definitely like to know the norminal impedence. If they are <8 ohm, that suggests they'll draw larger currents, and I'll have to choose the amp/receiver carefully.
Sensitivity is another important spec. You'll need a lot less power (i.e. cheaper amp) to push a 94dB (1watt, 2.83v, 1meter) speaker than a 86dB one.
Frequency response is important, if you read carefully. It must state whether it's a -6dB or -3dB measurement for the frequency it's stating.
-Ray |
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