I can see that. Making an integrated speaker that plays to 20 Hz is very difficult. The older designs had wide front baffles and diffraction issues. So somehow you have to get round it like B & W do. In addition you need 10" or 12" drivers that can meet the mids, and have an Fs 20 Hz or below and good power handling capacity. There are not many drivers around that meet that description.
As you know this was my solution.
These drivers meet the above criteria.
So the issue becomes, is there an advantage. Well that depends on whether you are a influenced by the work of the late Ted Jordan or not. In his long career he was convinced from his research, which was considerable, that separating harmonics in time was a bad thing and to be avoided or severely minimized. Well placing sub woofers crossed at 80 Hz at various places in a room make that separation a certainty.
So my measurements do show excellent time coherence of those speakers. On the other hand the 2 channel system in the family room with two remote subs, shows that it is far from time coherent as you would expect. Now I think I have pointed out before that you can build a speaker with perfect FR, that is totally unlistenable and speech unintelligible, because of time delay. So the question is when is it a problem. Well I agree with Ted, that it always is. And guess what? This issue is now showing up as an issue in speech clarity. So I think the AV environment, where dialog is so important, is going to bring this issue to the fore again.
Part of the issue is the recordings. Almost all use multiple mics, and therefore are a phase difference approach. That is another way of saying a time difference approach. Now that does not sound so appealing does it? Now the inventor of stereo sound, Allan Blumlein, thought this matter was important pre WWII. So he developed the intensity difference mic technique with his Blumlein pair.
Now for years I made lots of recordings largely for radio broadcasts, and I used the Blumlein technique. I truly believe this produces better more realistic recordings.
Of late a fine organist Jonathan Scott, has been giving lock down recitals in the fine organs in the North of England largely. Many of works are his own brilliant transcriptions for organ. He has been recreating the municipal organist of the late 19 and early 20th century. The greatest was Edwin H. Lemare. Anyhow his brother Tom does the recording and video work. Absolutely brilliantly, I might add. I note he uses pure Blumlein. Now the fidelity of those recordings in this room is absolutely superb. I will post some in another thread. They are a total work out for your whole system. They are highly enjoyable and very entertaining.
So this issue is I think, very important and we have a lot of rethinking to do on it I believe.
