It seems to me (my own opinion) that as a marketing strategy, newer speaker manufacturer focus their designs in the upper frequencies thus leaving us the consumer with but to buy a separate boxor now we called subwoofer for the low frequencies we desired to complete our sound fantasies whereas in the older models all are house in one box thus enabling us to save money and resources.
Let me post some of my thoughts on this:
(1) Over the past 20 years or so, technological advancements have made it increasingly easy to manufacture speakers with greater sonic accuracy, articulation and lesser compromises than ever before. Thanks to computer modelling techniques that can simulate design parameters in real time to optimize everything about a speaker. And because of economies of scale, they are made and marketed at prices that are accessible to a larger section of the masses or markets.
(2) Subwoofers are nothing new. They've been used by serious audiophiles since I've started this hobby in the mid 70s. Could even be much earlier. I remember seeing one passive Cerwin Vega sub that dwarfed our 8cu.fit ref. The difference between then and now is that subwoofers were large and hefty, often at chest freezer or ref sizes, and could be afforded only by the really rich. These days, with item (1) above, subwoofers have become a mass-commodity and their benefits have become so obvious to a much larger market at prices more people can afford.
Another difference is that there were few powered subwoofers in the past. They were mostly passive subs that formed part of an active bi-amped or tri-amped set-up that only the moneyed audiophiles can afford.
(3) It is a known accoustic principle that obtaining the best bass from speakers is inversely propotional to getting the best stereo imaging. Stereo imaging is a function mostly of mids and highs. Hence, the one box floorstander solution containing the tweets, mids and woofs is always a COMPROMISE in getting the right bass and the right imaging wherever they are positioned. Audiophiles have long known this and so promptly separate the speakers with mids/high driver from the bass-firing subwoofers. Bookshelf monitors were positioned as far from the boundaries or walls as possible. While subs were positioned closer to corners or wall boundaries. Wall boundaries muddle the stereo spatial information. But they reinforce bass frequencies to give them more body and slam. Thus, one-box floorstanders situated near walls or corners may have excellent bass, but produce the lousiest stereo definition.
The impression that subs are a recent phenomenon may be attributed to the behaviour of brands in the past compared to the present. The 70s and 80s saw many consumer speakers from Advent, AR, JBL, Polk, Celestion and from japanese mass brands like Sansui, Kenwood, Pioneer and Technics flooding the local market with large floorstanders with 12" woofers on 3-way 4-speaker systems that have them all in one box. They were impressive to look at and can be impressive to listen to in showrooms. They certainly can rock the house as I once owned a pair of Sansui multi-speaker boxes. They certainly had no need for subs. True. They have large ported enclosures that emphasized a certain bass region to give them the slam many HTs of today can benefit from. They were essentially boom boxes with mids and highs. Their large enclosures aproximating half a small chest freezer makes them essentially act as passive subs in their design. But they could never deliver more than a hint of stereo imaging.
Nor the musical details. Many 3-way 4-four speakers had drivers positioned so close each other muddling the frequencies coming out from each even on-axis. And some have midrange and tweeter drivers with cone sizes too large to deliver the mids and the highs effectively and accurately. These days, tests have indicated that mids can best be served with 5" drivers at the most, while highs can be served by light and rigid aluminum, titanium and soft dome tweeters 1" and below. A speaker enclosure need not be huge to accommodate such drivers. Powered subs will do the rest more efficiently
The young generations today who are into music and HT are very lucky indeed to go into the hobby knowng they can attain excellent bass and respectable stereo imaging only the rich could realize just a decade ago. Thanks to those newer highly aritculate bookshelf speakers that are very competent in delivering mids and highs, and the subwoofers located elsewhere that can go into deep bass mightily without requiring half the room space.
(4) Lastly, HT receivers of today need not be as powerful as those Kenwood or Pioneer stereo receivers of old. Comparing their power supplies, it should be obvious that the same KVA rating for 2-channel is about the same as the KVA rating for 5 or 7 channel operation in today's entry level HTs. Thanks in large part to the emergence of SELF-POWERED subwoofers. The HT reciver need not work that hard to pump out the bass freqeuncies which consume more than 60% of the availalble current reserves of any reciever or amplifier. The receiver can concentrate its power to deliver the mids and highs and some low mids. The sub can do the rest.
The subwoofer, in the meantime, need not have a very low THD amplifier circuit design nor does its amp be designed to reproduce ALL the frequencies so the power circuit can concentrate everything it has on amplifying only a small part of the audio spectrum. A new generation of switching Class D and Digital Class amplifiers that would otheriwse be considered lousy reproducers of mids and highs, but can deliver 500watts so easily, efficiently and cheaply for bass freqeuncies, are now in use to benefit subwoofers a lot. Very convenient and beneficial for both music and HT afficionados. They can have the best of many worlds at very friendly prices. Not something you could get as cheaply 15 or 20 years ago. Just my thoughts.
