So curious after last night...

[Mike^S]

curtis: too bad I happened to like the term brinkwall. lol


Wow, thats about the most inconsistent math I've seen in my life

Sound pressure level, doubles every 3dB. So if you double the speakers, you double the SPL, so it should increase by 3dB at most. Why/how 5-7 dB?

3dB is how much the volume increases when you double the power. When you double the speakers the volume goes up by 6dB. But that is only if the two speakers are right next to each other. If they are separated you will get less than that, probably around 4-5dB, as I said already.

Adding a third speaker will add another 1-2dB which is how you get 5-7dB.

[Mike^S]

Here is the math per Ed Mullen:

The difference in dB between any two sound pressure measurements is:

dB = 20 * log (Px/Py) (where Px and Py represent the two pressure levels)

If you double the sound pressure, then Px/Py = 2. Solving for the dB increase = 6.0206 dB. So a doubling of the sound pressure equates to a 6 dB increase in sound pressure.

Remember, you will only see a 6 dB increase when the two sound pressure sources are co-located and are identical in frequency, phase, and individual sound pressure.

Assuming each additional sub adds 3 dB is not correct as the number of subs grows. I know you are assuming incomplete acoustic coupling, but even then the math is not correct because you are dealing with log10 functions and they are not additive like that.

For the purposes of your comparisons, I would advise assuming complete acoustic coupling and using the following:

1 sub = baseline
2 subs = + 6 dB
3 subs = +9.5 dB
4 subs = +12 dB
5 subs = +14 dB
6 subs = +15.5 dB
7 subs = +17 dB
8 subs = +18 dB

[kinggimp82]

Why would you want to cross your 170's over with your sub @ 100Hz?

well my receiver only goes as low as 100 for x-over. my receiver is a lowend pioneer($179). i eventually want a nice reveiver.

id use the low level input but im lazy. also im confused to how they work if i want it for movie use. would my center (340 se) and surrounds (htm 200s) just produce more bass than the mains if i used my hsu stf-2 crossover? that really my main issue.