[pannayar]

Looking around in glossary / list of terms / google did not help give a definitive answer.

I come across this term often "Bass extension". When some review says "bass extension" is not that great, it would be good to know at what frequency and below it refers to, or more generally what it means correctly than just my current interpretation of it to mean "low end is not good".

I assume that it refers to approximately around 60 Hz regions and lower (which is sub-bass). So is it correct to say the bass extension is same as sub-bass? I think not, but would be good to clarify.

Is there a correct definition of it saying where the starting point is going all the way to 20 Hz?

Also is it sometimes said as base extension?

 

[old tech]

I'm not sure what is meant by bass extension is not great. The only thing that comes to mind is bass enhancement, ie a boost, is not great when it comes to fidelity (though subjectively, bass heads may prefer it). However, a linear frequency response of 20hz to 20khz is consistent with high fidelity. Frequency response outside this range doesn't matter as humans cannot hear it, but there is no problem with a linear response outside this range either.

 

[VNandor]

I think what reviewers mean when they say "the bass extension is not great" is that they perceive a steep roll-off below a certain frequency. I don't think there is any general consensus on how low the cutoff frequency and how gentle the roll-off should be in a headphone to not get called out on bad bass extension as this is fairly subjective within certain limits.

 

[bigshot]

I think the way it's used in reviews, it probably is referring to sub-bass. Generally, it would mean a roll off starting somewhere below 80Hz... the bottom two octaves that a subwoofer covers. But as it has been mentioned, the degree and steepness of rolloff would vary. Headphones generally don't do well with sub-bass anyway. When you get down low enough, super low frequencies are felt more than they are heard, and unless you've got a butt shaker in your couch, you can't feel bass with headphones.

 

[Davesrose]

Various studies have shown that human hearing can go to 20hz, or to (with different circumstances) 15hz. Current home cinema seems to be driving subwoofers to be louder at lower frequences (but this was also done in the 70s with Sensurround with amplified sub-bass). At these frequencies, it's not about what the ear drum is conducting, but what is being transmitted by bone (and what is rattling your vestibular system).

I think that when it comes to tonality of headphones, a lot of perception has to do with the balance of mid frequencies to bass and upper treble. Planar drivers seem to have "extended" bass when it comes to having a flat sweep in the relevant frequencies of 120hz-20hz. Folks seem to like Beyerdynamics, which I've found to be a bit too V shaped. Many of their models sacrifice mid-range detail to emphasize bass and upper treble.