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


In an earlier "Adiogoner" thread someone asked if anyone had heard speakers from Amphion. I quickly went to their web site to see their speakers and noticed on the Xenon model they incorporated a side firing bass design. Based on the little bit of knowledge I've picked up from more knowledgeable audiophiles it seems to me this set-up would create time and phase coherency issues not to mention sending sound waves away from the listener instead of toward them.

Are there advantages in this type of design I don't know about, because Amphion isn't the only manufacture employing this side firing woofer strategy(Israel Blum uses it)? What are the pros and cons?
128x128dawgbyte
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
Other than the AR 9's, 90's, NHT, Vienna Acoustics and Coincident Technologies, i can't really find any other speakers that made use of side firing woofers. I'm not counting Allison's and DCM Time Windows, as the woofers weren't so much "side firing" as the woofers were not side mounted so much as the cabinets were twisted sideways. Other than that, the only other thing that i can find was that EPI had a speaker that looked quite similar but used dual passive radiators where the 9's and 90's had active radiators. These were driven by one active 10" that was mounted up where the AR's mounted their 8" mid-woofer. If i can recall correctly, i think the EPI was a model 500 and made use of their popular and good sounding inverted dome.

Other than that, there might have been another company out of Europe selling a speaker with side firing woofers. I think i remember seeing some in one of Jerry Raskin's Needle Doctor advertisements, but i'm not certain. I thought i saw something about it using a Hiquphon tweeter, etc... Sean
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PS... I'm not including the Fluance ( Flatulence ?? ) speakers as found on Ebay in this list. I have a hard time believing that someone can build and market 4 and 5 driver towers of any quality for well under $300 per pair. Then again, who knows. Maybe these would shock me in regards to what they offer for the money. I kinda doubt it though : )