bitflipper
Record low "E" on a bass, then apply a steep LPF at 60 Hz so that all of its harmonics are suppressed. If you have any bass left at all, you'll probably have to turn it up by 20-30 dB to hear it. Now do the opposite: apply a steep HPF at 80 Hz so only the fundamental is removed. Surprise - the bass sounds pretty good, even with its lowest frequencies gone.

Your band is gonna love your quantum mechanics .... it will drive them nutz!

With this kind of test, you have to take what you hear with a grain of salt. Some of the variances you hear are the result of room resonances, not anomalies in your speakers' frequency response.
 
If I boost the low end like I might in a recording, my subs are clearly capable of reproducing 30 Hz (the lowest I've ever tested). But to hear 30 Hz as loud as 1,000 Hz it has to be 10,000 times louder. At that point, everything in the room is vibrating!

OK, I made up that 10,000x number. Before Drew comes along to correct me, it's only about 1,000.
 

drewfx1

Can you go ahead and do the math for a few examples for us slow types?

BobF

drewfx1

Can you go ahead and do the math for a few examples for us slow types?

 
Soitenly:
 
The lines show how loud frequencies have to be to sound equally loud to us as 1kHz does at the number listed for each line. IOW, it's basically the frequency response of our hearing. There are different curves because at different SPL levels the sensitivity of our ears to different frequencies changes. The unit used for equal loudness contours is called a "phon" which calibrates the listening level in dB SPL to 1kHz, so 80 phon basically means something like "frequency response so that all frequencies sound as loud to us as 1kHz does at 80 dB SPL". 
 
The line at the bottom shows the threshold of our hearing at different frequencies - you will sometimes see the abbreviation "ATH" which stands for Absolute Threshold of Hearing.
 
So lets say we are listening to that 1kHz at 80 dB SPL, we look at the 80 phon line - it shows that 30Hz needs to be 110 dB SPL to sound equally loud to us.
 
Since 110 - 80 = 30, the 30Hz needs to be 30dB louder. Since a dB is a logarithmic expression of a ratio, we can do a little math to convert it to a ratio and see whether "it's only about 1,000".
 
The formula is:
10 to the (dB's/20)th power = ratio
so
10 to the (30/20)th power = 10 ^ 1.5 = ~31.62
 
So at 80 phon, a 30Hz tone has to be ~31.62 times as loud to sound as loud as 1kHz.
 
 
 
 
And I didn't spell it all out in the first place because I figured Dave would get the joke. 

I can hear it down to about 23-24Hz on my ATH-M50's. 

sharke
I can hear it down to about 23-24Hz on my ATH-M50's. 

Nice