How much SPL should I be going for at 20Hz?

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#21
ORNJ said:
I know that subs are omni-directional but I was considering taking the PC12-NSD apart and just make a box that is front firing compared to downward firing to try and "aim" it to see what that does in regards to the nulls in the room.

BTW, it may be worth noting that the pc12-nsd that I have is the older version that has the BASH amp
Click to expand...
Aiming the woofer won't help. It is omnidirectional at low frequencies. Only the position of the woofer & port (distance from walls, floor, etc) will affect the room interaction.
 
#22
I was mistakenly under the impression that par on the hornresp input page meant parallel.
I was corrected and told it is parabolic.

Can someone explain why Bjorno's schematic in post20 shows parallel sides and the expansion is entered as par?
 
#23
AndrewT said:
I was mistakenly under the impression that par on the hornresp input page meant parallel.
I was corrected and told it is parabolic.

Can someone explain why Bjorno's schematic in post20 shows parallel sides and the expansion is entered as par?
Click to expand...

It does not matter if the area is constant, there is no expansion, you can choose whatever. How can you have a parabolic flat surface?
 
#24
What 'e said.

Par = parabolic expansion, so the curve follows a parabola. A conical flare has straight edges, Exp = exponential etc etc.

There was a really good image that showed all the different types of expansion posted around here somewhere. I'll see if I can find it.
 
#25
GM said:
It's a suspended ['floating'] floor, lapboard siding construction on a concrete block foundation and apparently the house has a ~14-18 Hz Fs as it vibrated hard enough to bust virtually all the sheet rock joints and 'rained' the ceiling down on us in the open layout living room where the system is, causing enough damage to the adjoining rooms to require all new ceilings in ~half the house.

Worse, it shattered one of the floor's concrete block pilings supporting the tie beams between the front/rear floor joists. This caused the main roof support to sag, buckling load bearing walls, damaging some water pipes, wiring, the list just goes on and on.

GM
Click to expand...

What exactly is the WAF of destroying the structural integrity of the house?

That is pretty impressive. What sort of SPL were you hitting? I feel like if I was playing organ music that was causing the house to fall apart my (insert significant person in your life here) would banish me haha
 
#26
Love Hertz

OK Mike, some of us must be curious as to how the research was accomplished to determine that 33Hz spec - and whether it applies to all
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I read in a car stereo magazine years ago, 1994/5, some guy had a sub under his passenger seat. His girlfriend was sat there and he ran some test tones, she commented from 30 through to 35 hz, that it felt good, 33hz being optimum.

The way I see it, she must have been most sensitive, I have read else where that the Clitoris has a resonant frequency of 33 hz. But I think there are factors involved that would need to be realised. Under wear and body fat could dampen the soundwaves, and apparently, one would require lots of S.P.L. Our body respond to bass and it has been utilised. The Disco beat, if I'm right, helps us to feel good when we dance.

Acoustic Trauma : Bioeffects of Sound
Sonic Weapons | Articles | Features | Fortean Times UK

Check out page 9 of this PDF
http://www.google.co.uk/url?sa=t&rc...0FoRqnKaafvWfSHbA&sig2=xyk4tp8QcSwcMNM-MhsU7A

Mike :blush::blush::blush:
 
#30
4Torr said:
Aiming the woofer won't help. It is omnidirectional at low frequencies. Only the position of the woofer & port (distance from walls, floor, etc) will affect the room interaction.
Click to expand...

The walls is what I was thinking about, it is placed in a corner that opens to the hallway and it is the best place I have found for the sub as the only other location I could put it had the couch in a null.

Now, even though it opens to a hallway there is a long wall that is right next to it, if that makes any sense, im really bad with words...

but I was thinking that if I could turn a sub to fire at the wall it would reflect more into the room...

Like I said earlier, I know that subs are omni-directional but I wanted to try and find a way to optimize it somehow....I know I could get some bass traps as well but seeing as how it is an open concept floor plan I dont think it will do me much good.

I have tile floors and a rug in front of the couch but I may even try and experiment with putting a rug under the sub.
 
#31
You will pick up a little room gain that way (getting the woofer close to the wall) and it may help smooth out the response a bit. The rug sounds like a good idea, too. Hopefully, the hallway and adjoining rooms are not acting as a bass trap. I have seen that happen at a friend's house.
Good Luck.
 
#33

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#35
ORNJ said:
Now with a subwoofer, from what I understand, you get the majority of the output from the first 100watts of power. So after that, half of what you are fighting is power compression.
Click to expand...
Not really. Power requirements are exponential vs SPL regardless of the type of speaker. Woofers do tend to suffer most from power compression but if you check the figures available, it is not "half" of additional power above 100W.
 
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