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

Yes,
The distortion I am quantifying is not anything like the original signal created, therefore is a whole new form of distortion. Just like harmonic distortion, or transient intermodulation distortion, in amps. But this is created by the drivers. Their amusical, and unique sound is audible, which is part of the premise. That "noise" keeps us from hearing the recording independantly. So, if distortion is defined as "any change from the original..." this is fundamental to that.
You know, I personally have always had some issues with the Maggies and the Stats, but there WAS the better parts of their reproduction that were undeniable. Also, horns, which have colorations, but do not smack the air that we can hear like a dynamic driver...so that change has SOMETHING which we all have grown accustomed to, and we just filter it out. Sort of like television. Someone made a comment to me that: audio in its own way is much more perfect than video. You can actually close your eyes and listen and imagine that you are there, but nobody ever claims that video could EVER be mistaken for the real thing. Say you put a camera on a part of a scene, and introduced the video signal into the equation, and balanced the color, brightness, and everything perfectly; you still could never, NOT NOTICE. I had to agree with them in principal. ALTHOUGH, that really kind of enforces my point about audio; in that we block out the unreal parts. I further contend that this is part of LISTENER"S FATIGUE. The harder our brain has to work to recreate the real thing (a piano through speakers versus a real piano) the more fatigued we get. This is why sometimes our system sounds poor, and other times it sounds great. We are the X factor, our brain's willingness to 'complete' that incomplete equation, or not complete it. Think back, usually when you are mentally fatigued,sometimes that's when if you try to listen, and get in that perfect groove, wherein you can 'pretend' it's real, but your brain is not willing to do so, you just end up turning it off in frustration.
So, this annoying driver 'noise' is always in evidence, we just have 'learned' to disregard it. Bass, being the most obvious of all, because of the displacement severity, was the first place I really honed in on it.
Thanks for reading.
Larry

Lrsky, just about 2 weeks ago I read an article in the news papaer (NY Times or PH Enquirer, can't remember which) which reported on a story concerning a German cable channel that transmitted a signal of a fire that was intended to replicate a fire place. Well, an elderly woman called the fire department claiming that her TV was on fire. When the firemen were interviewed they said that this happens periodoically, and recently an elderly woman threw water on her TV in an attempt to extingush her burning TV. This caused an electical fire that spread to neighboring apartments and the building had to be evacuated. I can only imagine the blazing effect HDTV is going to have! BTW, the fireman suggested that most people should be able to distingusih a real fire from a televised one.

Was any alcohol involved in that story, you know, the nightly nip? HA!
Larry

There was no mention of alcohol in the article. I'm glad you got a laugh from it. I know I did. In fact all the international news that day was so depressing prior to that article, I stopped reading that days news, so that I could leave on a humerous note.

Lrsky: Your observations pertaining to distortion are right on the money. A large part of the distortions that we hear are THD, which are comprised of higher frequency harmonics of the orignal signal. Facing the drivers away from our ears "dillutes" the percentage of those higher frequencies that we hear. This causes them to blend in with the other signals being reproduce, minimizing their effects and noticeability.

As a side note, it is the harmonics of a lower frequency signal and the "leakage" through the crossover that allows us to localize low frequency signals. The more effectively that one can minimize the distortions that we hear and the harmonic overtones that the driver generates, the less likely you are to locate the source of bass. Obviously, facing drivers away from you and running a sharp crossover at a very low frequency is about the best that one can do in this respect.

As far as output levels go, if you want low bass at high volumes, you've got to move a LOT of air. While one can do this with a few drivers that can provide huge amounts of excursion, long excursion drivers tend to have their own problems and introduce distortions into the system. The other approach is to use multiple woofers in some type of array. If the array loads the room in multiple directions, you can achieve great bass output while exciting the room nodes in a more natural manner.

As a side note, the mains of my HT system each have a side firing 12" on opposing cabinet walls. The surrounds have side firing 10's arranged the same way. My bedroom system uses down-loaded subs that are currently crossed at 65 Hz and my main system uses four dipolar 12's per side in sealed low Q boxes. My office system radiates in a 360* horizontal pattern from a single driver, so it too loads into the room differently than most "conventional" speakers. The only "normal" speakers that i'm currently running at the time are front loaded horns and event these aren't "direct radiators" so to speak.

I'm also building s system for a friend that uses eight 12" woofers per cabinet. The baffles are as narrow as possible and make use of a very large line array of mid-woofers and tweeters ( power handling, high sensitivity, lower distortion due to reduced excursion and more linear radiation pattern into the distance ). Flanked on each side of the baffle sloping backwards will be four 12's per side in a stuffed but open backed cabinet ( damped open baffle ). I had to look carefully at the electrical characteristics of the woofers to do this, but i think that it will work quite well. Sean
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