Originally Posted by vitaminc
Could someone please delight me how to read the graphs? The Verticle is sound level in dB (loudless) it seems like, but what is the horizontal? And what do people mean by "forward" or "flat"?
Thanks much for the help!
You're right, vertical is dB (loudNESS, or volume). And as xcjago said, horizontal is the frequency of the tone being tested. Someone else pointed out that the B&Ws seem to have less THD, or Total Harmonic Distortion, at these frequencies than the other two. In the graphs you'll notice the peak is at the fundamental frequency, or in other words the frequency of the tone Craig played to test the bass response. But you'll also see a smaller peak in each graph at double the test tone's frequency, which is musically speaking one octave higher. So in the 36 Hz graphs, there's a smaller peak at twice that, or 72 Hz. That's because the speaker's cones are resonating at not only the fundamental frequency, but also at harmonics of that frequency, starting with one octave up. If the graphs showed a wider frequency response, you'd probably also see smaller and smaller peaks at regular intervals going up.
(It's also possible that some of these harmonic resonances are room interactions and not just speaker cone resonance, right Craig? Please correct me if I'm wrong about that... I'm fairly sure you don't have an anechoic chamber in your house... YET.
In a perfect world, a perfect driver would only show a peak at exactly the frequency of the test tone, assuming Craig is using pure sine wave tones. The rest of the graph would show a flat line at 0 Hz.
The definitions of "forward" can be interpreted different ways... Sometimes people mean the speaker has an emphasis in the upper midrange frequencies, which make them sound brighter, bringing out vocals and similar stuff. But I believe the term is really more about the presentation of the material... So a speaker that's described as more "forward" would make it seem as though the vocals and other midrange instruments are more forward in your room, and you're closer to the performers. Whereas a more "laid back" presentation would make it seem like the singers and performers are farther away from you in your soundstage. In other words, a more forward set of speakers places you in the front rows, where a more laid back set of speakers places you several rows back.
Everyone agree with this description? These can be fuzzy terms as they're bandied about in these parts...
Oh, and "flat" simply refers to the speakers' measured frequency response. A flat response, shown by a flat graph in a pink noise test, means the speaker reproduces all frequencies within the audible range at the same volume. In the real world, this is almost never the case, and truly "flat" speakers don't always sound good to everyone. There are many other factors involved, but the frequency response is a commonly used test to get an idea of how a speaker should sound and perform.