Originally Posted by warpdriver
Take your hands, cup them, put them around your mouth and say something. Your voice has changed and the sound is more directional. If you put speakers into a cubby, the sound changes again. Sound travels outward like a wave. (think of what happens when you drop a rock into a puddle, it travels outward in every direction). Think of what happens when you put the speaker into a cabinet, the sound waves travel sideways and get diffracted by the edges of the speaker itself, and by your bookshelf cabinet. You are changing the effective baffle area as well depending on your placement. Porting relies on airflow to allow the speaker to resonate at a certain frequency thus increasing bass response. When you put a ported speaker inside another enclosure, you are effectively changing the airflow and/or getting boundary enforcement as well which will throw off that naturally tuned bass the speaker maker intended..
Yes, it does indeed sound like rear ported speakers in a confined space, or up against something (at the rear) is a bad idea.
That said, your initial commment (if we're not talking about ported speakers) in a confined space does come across as a little bit voodoo. If you're talking about the location of my exiting center or right speaker, these two speakers are sealed so (I'd imagine) the sound mostly eminates out of the front, from the speakers themselves. So I find it hard to see how placing my center and right speaker in their current locations could really affect their sound? There is no surface beyond the speakers themselves, only to the sides...
And indeed time spent moving the speakers around and even placing them on stands seems (in my case) to verify no real difference in sound.
To use your analogy... Say something to someone infront of you... Now put your hands either side of your face, about 1cm away from your cheeks, and not in anyway infront of your mouth... Now say something... Sounds the same...
There is absolutely no intent to be argumentative or anything of the sort here, but in a lot of areas you tend to find people can get carried away with the theory, rather than the practicality. And I'm a fairly logical guy to I need to see and understand why something works or has an effect to believe it...
Case(s) in hand:-1) A rear ported speaker in an enclosed space.
If there is sound emitted from the port (I believe there is?) then obviously covering it, smuthering it, is going to affect things. Makes absolute sense.2) - Your speakers must be at the same height. 5" will affect things.
Now, if you're in laboratory conditions, with high end equipment, I can imagine you might be able to detect this. But in a conventional room, with irregular wall, furniture, where you don't sit in a single chair in the middle of the room, I cannot see the logic in it at all...
In my particular case (with low end equipment) I can detect no difference when moving speakers up and down by say half a foot. Do an experiment at home. Stand a reasonable distance from your speakers and move your head up and down 6"... Is the sound different?
Furthermore, in many setups, you won't be listening from the exact center, and at the exact height of the speakers. As such, depending upon your position, the relative height (angle) to the speaker will vary. From one position, the left speaker may be at a far different vertical angle than the right for example.
So unless, we're talking about perfectly setup home theatres, it is a completely unrealistic/unecessary requirement IMHO.
Again, there is no attempt to cause arguments etc here... More a healthy questioning/reasoning really.
And indeed, it's clear that if I contemplate upgrading my front stereo speakers, I risk my center speaker sounding 'out of place'. And in the case of the MS 902i's the matching MS 905 will not (quite) fit where I want it.
But the question still sort of stands, if I were to put 902i's and a 905 on my system (ignoring space and location) would it sound better? Or is my amp at its 'sound quality limit' with the existing speakers, so putting on better speakers will not improve sound at all - This I have no experience or knowledge of, hence my OP I guess...