How do you know if your sub is 'doubling' or doing it's true output?? (1 Viewer)

[Keir H]

Specs from the manufacture are one thing but I've learned that they only can mean so much depending on your room and placement. I'm trying to figure out true frequency responce ratings for a Sony SAWM-40 (20hz lists) in my 14x17 room that's opne to another smaller room. Just what is doubling? How do I know if the Sony is doing this to get the ratings it's listed as?? ALso, what's a good test tone CD with music material also that I could buy easily without hunting all across the web for one?? thanks everyone.

 

[ThucN]

what's a good test tone CD with music material also that I could buy easily without hunting all across the web for one??

I don't know what you mean by a test tone CD with music material, but if you just want a CD with some test tones, other test signals, as well as some music tracks, I recommend Stereophile Test CD 2. You can order it on their website.
As for whether the sub is "doubling" its output or not, that's tougher. You could, for example, play a 20 Hz tone and then measure the output with an SPL meter. But that result may be skewed because the sub is doubling its output (40 Hz), thus making the meter read higher.
I guess a more accurate way is to connect the output of the SPL meter and feed it into the mic input of a computer sound card. Then by playing some test signal (pink noise?), use some software spectrum analyzer to read the actual levels at any frequency. I've never actually tried this, but I think this is the general procedure.
Of course, feel free to correct any of this.
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TqN