John , if I don't agree entirely with evrything you've said...I agree enough not to pursue it any farther...which I suppose may cause you to immediately review your prior response for all the *mistakes* you must have made?(joke).
The only comment I would like to respond to is...
:::If you double cabinet volume, double amplifier power and double the drivers used, yes, I think you are correct, you get an additional 6 db of volume-when it all takes place in the same enclosure.:::
Taht may ot may not happen...other vaiable to consider in this case. For example you MAY get a 6dB increase at 40hz, but only a 3dB increase at 30hz...but let's save this topic until *we* all agree on the original topic.
:::Once you separate them all into two different enclosures with two different power amps, I’m a little fuzzy about what happens.:::
Assuming the two enclosures are identical (including the amplifier power used)...there will be in *theory* a 6dB increase across the board. IMO(deon's opinion differs I think)...I think the two drivers(enclosures) must be very near one another to approach this *6dB* gain. If, for example, you had two (identical) subwoofers on either side of a FPTV screen(say 6 feet apart)...you'll probably only receive a3.5 - 4.5dB increase in overall headroom.
:::Deon chimed in that it has to do with the relative distance of the enclosures vs the size of the wave-lengths produced and that makes a lot of sense. Perhaps had you been able to articulate this to Stuart, your discussion wouldn’t have gone on for so long.:::
That's possible, though like I mentioned, I don't entirely agree with deon in this instance. We both realize the +6dB gain aspect, but deon and I differ about the location of the enclosures required to receive the full 6dB increase(i think-hopefully, deon will see this?)
::: But rather than doing so, you instructed Stuart to go look it up….where, on that subwoofer design book he has sitting on the coffee table?:::
To be honest, I don't think I've ever seen this *theory* challenged...I've seen instances of *brain farts,and typos* where someone makes the mistake(and then immediately admits it)...but I cannot remember an instance in which the *+6dB* theory was honestly contested for so long. So,yes...I probably handled it poorly...for it was a new experience for me.
::: When ever you instruct people to go research a project rather than giving them exactly what they need to know, I think you can expect a protracted conversation. :::
Possibly...but from my POV, I ended up defending a 2+2=4 formula. If you're going to question(what I consider) basic acoustical theory...theory that is referred to in almost every text I've seen on the subject...(imo)you should have a leg to stand on.
Beleive me, I question *accepted* theory almost daily.
1)ROOM GAIN
2)Acoustical Energy Inversing (aka...the old place your sub in listening position and crawl around the room to find the best bass trick)
3)"Proper" LFE channel calibrations.
But when I DO contest these accepted theories...I do so armed with many hours of RTA data.
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