Originally Posted by Adamg (Ret-Navy)
I must admit you have me riveted to your every post! Your thinking process and ability to clearly convey the hypothesis being discussed is remarkable. What you are describing is nothing short of a breakthrough in the understanding of Human Hearing as it relates to the subjective "Heavinss" of a subject Subwoffer FR. The revelation that this "Heavyiness" presence is not conditional upon volume (gain) level and/or Max Output numbers. I could never put my finger on it, but somehow I knew the Subs Max Output did not tell the whole story. And the Max Output numbers by itself might just be entirely misleading . The subs native tune can be used to surmise if a particular Sub will sound "Heavy" or "Light" in a comparrision situation. Even at very low volume levels I can still feel the depth and weight of my Subs. Looking and comparing Sub output graphs like you did will tell us more about how a sub will perform in real world terms, and should give us new tools to employ when helping others chose between Subs to suit their particular needs/tastes. You certainly helped me further understand how to compare a subs native tuning frequency, from one sub to the next. You provided a light bulb moment when you informed us that this Native tuning curve exist at all output levels.
This I did not fully understand nor comprehend.
Keep up the great thinking Mike. You are expanding our shared understanding of bass and how each specific sub has its own unique sound signature. Additionally you have discovered and shared with us a new method of how to see this performance trait in the Sub native tuning graphs. Very intriguing reading. My compliments Sir!
If you have the time and inclination, I would love to hear your analysis of the 2400ULF Native FR.
Thank you very much for the compliments, Adam! They mean a lot to me!
I have to admit that I am pretty excited about how some things have fallen into place for me lately, starting with the linchpin concept that a subwoofer's native response doesn't really change, irrespective of volume level, unless we manipulate it with internal or external DSP.
Sometimes, we don't know exactly what we know, and that's where writing-out explanations helps us to clarify our own thinking. Like you, I have been too fixated on max output. I have been making distinctions between subwoofers which emphasize mid-bass frequencies more, and subwoofers which emphasize low-frequencies more, for quite a while. But, subconsciously at least, I was associating the differences between those subwoofers with higher volume levels, as if that were the only time that the differences would really be noticeable. And, I have seen most other people on AVS making the same conscious, or unconscious, assumption.
Explicitly recognizing that the actual frequency response of a subwoofer is not volume-dependent allows me to see that there could be noticeable differences in sound between a subwoofer which emphasizes mid-bass, versus one that emphasizes low-bass, even at moderate volume levels. And, that has some implications even for music listening, and might explain much of the difference that some people might hear between sealed and ported subs.
Subwoofers which play low-frequencies relatively louder with respect to mid-bass frequencies would be a pretty good way to describe the difference between ported subs and sealed subs. And, as you said, this could also certainly help to explain what you have heard in moving from your PB13's, with the Bash amp, to Cap 2400's--even at moderate volume levels. (I will try to tell you what I see of the Cap 2400's native response a little later.)
I think that looking at the overall slope of the frequency response, rather than just max output, may have significant implications for those of us looking to upgrade. Max output deals with total SPL, and that's still important. But, from my observation, relatively few people are upgrading just because they can't play their subwoofers loudly enough. That certainly does happen, but I believe that part of the reason many of us are pushing our subwoofers to fairly high volume levels to start with is so that we can hear low-frequencies better. And, I believe that most people who are upgrading are already aware that they want to hear more low-bass.
Sometimes we want to hear those low-frequencies better just because we really like bass, and because we can't hear those frequencies in quite the same equilibrium as we can the higher bass frequencies. Sometimes, it is specifically in order to emphasize the low-bass special effects that make action movies and blockbusters so exciting. The low-bass there can be a little bit addictive. But, whatever the reason, I believe that most people upgrade their subwoofers in order to emphasize low-frequencies more, and if that is true, then paying attention to how a particular subwoofer plays low-frequencies in relation to mid-bass frequencies
is very important.
It is important because that relationship won't change much. It will always be the subwoofer's native response, and depending on room size (and the resulting room gain), low-frequencies may be emphasized too much, or not enough, almost irrespective of listening level. And, on the other hand, if someone is upgrading just for more total SPL, or for more mid-bass SPL, then looking at both the max output and the native frequency response of subwoofers will still be helpful. One of the things that I also think is especially important to recognize is that we are likely to have more mechanisms (such as cascading crossovers) to emphasize mid-bass frequencies, than we may have to emphasize low-bass frequencies. So, having a better understanding of a subwoofer's native response could be a real factor in our ultimate subwoofer selection.