Stupid speaker test question...please help a n00b


Why aren't speakers tested by measuring the output sound waves vs the input wave signals? Would this not be the easiest way of testing distortion introduced by the speaker? Assuming you control all the other parameters of the test of course...

Thanks for the help!
spartanmorning
Unsound,

While I completely agree with your observation re: vast majority of music lies >150hz, the octave to octave balance of a speaker is priority one for me. If the 3 octaves (or so) below 150hz aren't well balanced with the remainder of the speaker's bandwidth above, I won't be able to live with that speaker. To me, this concern is far greater than midband accuracy, imaging, dynamics, etc.

Anechoic response is often used to demonstrate how well balanced a speaker is from bottom to top. IME, once you get that speaker into a listening room, the story is wildly different.

Marty

PS I now use Audyssey on my 2.2 channel main system for this reason. It eliminates the guesswork.
I think products like the Audyssey just might well be the game changer in the near future. Still, knowing what a speakers low frequency output is in an anechoic chamber gives one advantages when making an initial purchase. Even room correction can't make a speaker do what it's not capable of. Truth be told, I doubt most manufacturers have access to anechoic chambers that are accurate below 200 Hz. I suspect most use computer modeling to predict anechoic response that low down in frequency. As compromised as that might be, it still allows for apple to apple comparisons, that can be user modified as needed.
I agree with a lot of your observations here. However, (whether true or "quasi" - and, as you note, it's often hard to say how the numbers came to be) the anechoic data that I've seen published for speakers has not been very useful for my main FR concern - determining that a speaker has an acceptable octave to octave balance in my room.

The published data has had little (if any) correlation to what I hear (and measure, for that matter) in my own listening room. Obviously, I can't speak to your experience applying this data. If you find it useful in "apples to apples" comparisons, that's great. I just can't say that it's been useful FOR ME in that regard.

Marty
Unsound... Everyone has access to a perfect anechoic test chamber. It is called "outdoors". I think it was KLH when it was a startup who used this.
I know that some independent testers (HTShack.com) use a parking lot for anechoic style testing. The Canadian Nat'l Lab has a large chamber that some Canadian manufacturers use and Stereophile uses a "quasi-anechoic" measurement technique that I've never seen thoroughly explained. Either way, the FR numbers that result from any of these tests never particularly reflect what I get in my own room.

Marty