"Tom1W" wrote in message
...
I would like to pose a question to those who understand speaker
technology: Why
is it that we do not see as many loudspeakers these days with woofers
beyond 6"
to 8". I recall many years ago, that more "serious" loudspeakers were sold
with
at least 10" woofers and some even as large as 15". Is a large woofer
needed to
evenly and to accurately and loudly enough present the lowest bass tones
or has
technology changed where size does not matter?

As others have mentioned, it's partly a matter of size of the enclosure.
However, large woofers can fit in very compact enclosures.
Acoustic Research (AR) did this for years, with very impressive results.
The AR-58BXJ is one of the smallest full range loudspeakers ever made.

Compact designs that use large woofers are usually based on the acoustic
suspension principle. Although speaker designers generally swear by acoustic
suspension as providing the highest quality bass, it is a low efficiency
system. In the past, there was a market for high performance, low efficiency
speakers, for use in conjunction with powerful basic amplifiers. However,
with the advent of home theater, the basic amplifier is no longer a
mainstream item. Home theater receivers are not capable of powering acoustic
suspension designs to expected volume levels.

Consequently, there has been a replacement of large-woofer acoustic
suspension designs with ported designs using lighter cones and smaller
magnet structures that can be driven by typical home theater speakers.
However, these designs tend to exhibit large phase anomalies, as well as an
inevitably steep rolloff of bass below the design corner frequency. They
don't produce bass of the same quality, but people don't seem to care these
days.

It is possible to build ported systems that use large woofers, but tuning
requirements result in large cabinet volume, larger than is accepted by most
buyers today.