Does this sub produce down to 36 Hz or 42 Hz?
ANY loudspeaker (ever tweeters) will easily "produce down to" 1Hz. No problem.
NOW HOW LOUD it is at that freq is a TOTALLY different story!
There are all sorts of different "games" that manufacturers "play" with specs. Some more than others.
In MY opinion (others are willing to differ), the low freq response HAS to be tied to the rated sensitivity-or else it has very little meaning.
For example (I'm just making this spec up) let's say the rated sensitivity is 100dB.
The freq at which the response in 3dB down (97dB) should be the -3dB point. The point at which the level is 10dB down (90dB) is the -10dB rating.
If these are not tied together-then you can come up with all sorts of specs that don't mean anything.
In the above example let's say that there is a peak in the response at 500Hz (we are talking about a sub here). The manufacturer could rate that peak as being the "sensitivity", but it would be VERY misleading as to how loud the speaker would be in the intended range it would be used.
Let's say this peak is 6dB higher (106dB) than the "realistic" rating of 100dB (as measured down in the sub range). This would mean that you would need twice as many subs to get the levels you would "think" you would be getting-based on the rating at 500Hz.
Yes the numbers MATTER-and it is VERY important to not only look at the "simple number" but ALSO the measured response-to get an idea where the numbers came from.
If you don't see a measured response then you have no idea where the numbers came from or how realistic they are.
There is no standard-so you HAVE to look a bit closer when comparing specs to see how well they REALLY stand up to each other.
Of course none of the specs even begin to tell what the speaker actually SOUNDS like.
That is a totally different subject-for which I am not sure there is any metric or spec-other than subjective.
And even THAT is very different. Some people like a smooth response-others like the "agressive ice pick in the forehead" type sound. Yes I have had a good number of people tell me over the years they want the system to "hurt" the audience and "drill through" the audience. So they prefer a system with "an edge" to it.
Oh well-------------------