[bummrush]

Why is there so much bass variability in recordings?

[Barry_NJ]

As many reasons as there are recordings.

[bpape]

Honestly, a lot of it has to do with the room it's mixed in.  That's one of the biggest issues is getting the bottom end to translate properly into the outside world.  When you mix in a room with insufficient bass control, it appears that you have a lot more than what you really do so you tone it down.  Then, when you get it outside, it can be thin and anemic. 

Another reason is simply that many recordings are made for radio where it's EQ'd anyway so they cut back on the bottom and can compress it more to win the 'loudness wars.'

Bryan

[Russell Dawkins]

good question and I think the answer is that the bass is the region of greatest variation between different playback systems, both in the studios and in homes. This makes the aforementioned translation a bit of an exercise in double guessing on the part of the mixing and mastering engineers.

Some reasons for that would be:

1. speakers themselves vary enormously in the bass region due to varying tastes and abilities on the part of speaker designers. In about 40 years of attentive listening I would say that I've heard reproduced bass sound close to "right" fewer than ten times. The bass driver interacts strongly with the box and the designer is called upon to perform miracles in this region, whereas the midrange driver, if there is one, typically does not rely on box tuning, but mainly absorption.

2. speakers interact strongly with the room in the bass and so a large measure of what is heard in any given studio or home situation is attributable to the room. This summer take your speakers outside onto the patio, if you have one, and learn just what your room sounds like. You may find your room's contribution is not to your taste at all (to put it mildly) and want to start listening in the nearfield.

3. (a lesser factor) the effect amplifier damping factor has on speaker performance in the bass both in the design process (when the speaker is being "voiced") and in the home. The main reason solid state amps sound different to tubes in the bass on the same speaker is the greater control of higher damping factor inherent in solid state. Some speakers/rooms benefit, some don't.

[jimdgoulding]

Good post, Russell.

[Steve]

May I add that all the electronics (which includes parts in each component) in the chain can and do affect the bass quantity and quality. I believe the output impedance Z (damping factor) was already mentioned as affecting the bass.

Hope this helps.
Steve

[denjo]

Good and interesting post!

On the subject, can I ask what is meant by getting the bass right? Also, what do you folks understand "one note bass" to mean? I have a Bryston B100 and Accuphase E-450 and must say that they both handle bass quite differently. The Bryston B100 is heard and one can quite easily follow the bass lines on a good track. With the Accuphase one feels the bass more than it is heard and it goes quite low but the impact is not "slam in your face". I have read somewhere of someone who puts the point across in this way - its like hearing a good bass electric guitar rather than a good acoustic bass guitar. Which is more accurate in the portrayal of the bass?

Best Regards
Dennis

[Russell Dawkins]

By getting the bass right I mean producing convincing sounds in the bass - an acoustic upright bass should sound like itself, likewise any other bass instrument as well as the bass component of hall sound. I'm sure most of us who have heard a good orchestra in a good theatre know that the orchestral bass drum heard under those circumstances doesn't resemble very closely at all what is typically heard in the living room re-creation.
Bass reproduction in the home is normally plagued with standing waves in the listening room and too resonant and non-linear response from the speakers. Because domestic considerations tend to demand smaller boxes and woofers than would be ideal, low bass output is commonly augmented by resonant systems, typically ported. More expensive solutions to the same problem (getting big bass out of a small woofer in a small or narrow box) include active crossovers sending contoured signals to the bass drivers of sealed boxes, and servo-feedback systems where a sensor is attached to the woofer to keep its output consistent to frequencies below system resonance.
Sometimes the controlled resonance approach is used with skill and restraint; other times not. An example of "not" would be the extreme one note bass I hear in some cars with loud bass systems, sometimes rattling trunk lids, where one note is so strongly favored by a massive system resonance that any bass signal anywhere near (and I mean within an octave of) that favored frequency is magically transformed to that frequency and is boomed triumphantly for all the block to enjoy!
(edited in an attempt at clarity, a couple of hours after the post)