Side firing bass designs - Pros & Cons?...

Thanks. It took some time, years, in fact to quantify what is so obvious after we 'notice it'. I am pretty convinced that the distortions are of another order, (hence the idea for the paper)and of more significance, than just harmonic distortion, even though what you say is accurate, (usual for you Sean). When I think of harmonic distortion, it is more easily placed than this, since this has been part of our universal listening experience most of our lives. It's funny, but when some people would go bonkers over Stats, or Maggies, over the years, I wouldn't quite understand the magnitude of their objection to that pervasive distortion that drivers were making. I am pretty sure it is several forms, hence the new name ADD. ADD will be a combination of harmonic, transient intermodulation, and on and on...
When I look back, the people who loved Maggies so much, or Stats, so much, were usually newbies, (this is simply my isolated experience, and first hand retrospective observation, not emperical) who did not embrace universal driver distortions like the rest of us have. They only knew that it sounded more 'right'. From that perspective how can I disagree? The MBL's have much the same allure, as well as the original Heil Air Motion Transformer, which squeezed the air, rather than slam it. (I guess finesse wins again in some reality huh?).
I have a lot of work to do on this, but as I think about it,
I was enamored with, (and still am) the Pipedreams speakers for much the same reason, (forgetting bass here for a minute, and degrees of taste and particular 'audiophile bias') since they have 80 plus drivers moving fractionally the distance of typical speakers. Moving what has to be almost at the sonically invisible, magic point of distance from rest position. Think of the relevance of comments we all hear and use, relative to, "effortless" and "lifelike" that we hear in descriptions of well done multiple driver array systems. This is no colossal accident, but further potential evidence of the validity of this driver motion distortion, which I am working on and have (potentially) quantified.
Thanks Sean, your system that you are working on sounds interesting.
Von Schweikert Audio, and I (don't get me wrong it's Albert's baby, that's for sure)have been talking about a system which employs multiple woofers, in two separate towers, (limiting great excursion distance) with 11 drivers per mid/tweet towers, which hopefully will be released at the CES in Vegas, in Jan., 2004. The same thing as some older systems such as the Original IRS (I think it was Infinity Reference System). But back then, with limitations of crossover excellence and driver technologies, (not a criticism just noting the twenty year gap in time/technologies) it seems that they sounded a little confusing. But to replicate that today, with better drivers, that is exciting to me.
Best,
Larry

Sean, I feel like I'm your Dad. I lived with several versions of Legacy speakers from 1986-2000. I've since moved on to Vienna Acoustics. FWIW, I thought the Legacy speakers were a great value when I first heard them, in 1986. I think their quality slipped some over the years. The VA's are placement sensitive, you have to keep those side firing woofers away from surfaces that can be reflective, such as walls. When I had the woofer (1 in my Strauss) firing out towards the wall, the bass was slow and muddy, as I mentioned earlier. In my room, they need to be out at least 2.5-3 feet from the rear wall, with the woofers firing inwards. This will allow the rear port to 'breath', and the bass will tighten up quite nicely. In my experiences, you really cannot judge the true sound of the VA's in a Tweeter chain store, they really have no idea how to set them up. They don't use quality equipment either. I've actually seen them have the Mahler's ($10K) being demo'd with the speakers in a corner, being driven by a Denon 70 wpc receiver and a Pioneer dvd player. It sounded horrible. You'd think they'd put a little more effort into trying to sell $10K speakers.

BTW, I do have 3 sons, ages 12-19, one named Shane, but they don't have any interest in my hobby.

Regards,
John

Lrsky, in multiple driver speaker designs like the Pipedreams and GR Research Alpha LS how do they take into account line source dispersion patterns? It would seem to me line source changes tone balance with listening distance.

Thanks for all the wonderful input, I knew I could count on you guys! :-)

Dawg,
That, my friend is an excellent question. The Pipedreams use a proprietary 'series/parallel' wiring configuration which ameliorate the lobing effects which is what you are asking about. Otherwise comb filter effects would cause a disturbing cancellation, pattern, which would make them very non linear.
The designer, who I know, won't talk about it in any detail, and I am honor bound to not discuss it more than I have mentioned already.
I hope this is enough to answer, what I consider to be a very good, and intuitive question.
Best,
Larry

You'll get comb filtering no matter what you do when using multiple driver arrays, but that can minimized by careful design and wiring. I ran across a website that was mentioned on Madisound when doing research on line array's that goes into detail regarding comb filtering, driver size and spacing, crossover frequencies and slopes, etc... I printed it out as it was worth having around. If i can remember correctly, the website was run by a gentleman by the name of James R. Griffin.

While i can't find his specific website, i was able to find one that had his work along with that of a lot of other line array advocates all compiled together as various downloads. At least some of Jim's work can be found here and is titled something to the effect of a "linus array". Sean
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Line Array information