Frequency Range ( 5Hz vs. 15Hz)
Feb 27, 2013 at 11:39 PM Thread Starter Post #1 of 35

unpimpauto

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     How much does this affect the impact of bass? If it goes all they way down to 5Hz, wont it have more impact even thought you wont hear it, you will feel it? This of course only applies if the audio source goes down that far. I am pretty new to this and haven't gotten to try many headphones. How much of a difference will it be?
 
Feb 28, 2013 at 12:34 AM Post #2 of 35
Headphones don't move near enough air to make the lowest audible frequencies matter that much-- let alone the subsonic frequencies.  A good headphone will get you down to 30hz solidly, but even there you begin losing out on their visceral properties that you'd otherwise feel with fullsize speakers.
 
Feb 28, 2013 at 3:41 AM Post #3 of 35
Most "frequency response" specs published by manufacturers are bogus. Almost everything produced in the last 50 years is claimed to have at least 20-20 range and recently some manufacturers started coming up with insane numbers like 5Hz or even 2Hz. Yet even in 2013 many headphones don't reproduce sounds below 30-40Hz at any listenable volume.

Have a look here and compare with published "specs".
 
Feb 28, 2013 at 5:30 AM Post #4 of 35
the truth is an easy 50|50 answer.. maybe yes, maybe no.
 
there is quite a lot about the audio stopping at 20hz because people dont realize all the layers that make up an audio signal.
there are 'moments' in an audio signal that could be lower than 20hz .. sometimes a fraction of 1hz
 
what good is the frequency information? well that is a game or puzzle ment to be there for people that care to find out.
for example.. maybe the frequency response says 5hz , but you cant hear 20hz or 10hz and even 30hz is kinda low .. so then maybe the information is valid for people looking to write their own custom digital sound processor to match harmonics using nothing lower than 5hz (or maybe it is to say most use 10hz or 15hz but it is okay to go down to 5hz with those speakers)
 
and yet again..
maybe the speaker is really junk (or it was good at something but terrible at something else) and they just ran the frequency response test and copied the results no matter how confusing it looks .. as if a drip on your shirt while eating.
 
speaker 'motors' can be made to prove either arguement wrong.. it really is 50|50.
 
Feb 28, 2013 at 11:07 AM Post #5 of 35
It's not that you can or can't hear below 20Hz, it's just that your ears aren't very sensitive down there so it takes a lot more energy to hear it. If you ever get the chance to watch a real-time spectrum analyzer that goes to 10hz or so with a flat mic, you'll understand the blessing of not having sensitive LF hearing. Lots if noise down there, but almost no useful information.

Then there's this thing. I've heard it, seen it and talked to be inventor. Yes it works, and yes there's stuff to hear below 20Hz, if you have one of these beasts:

http://www.eminent-tech.com/rwbrochure.htm
 
Feb 28, 2013 at 11:39 AM Post #6 of 35
Quote:
Then there's this thing. I've heard it, seen it and talked to be inventor. Yes it works, and yes there's stuff to hear below 20Hz, if you have one of these beasts:

http://www.eminent-tech.com/rwbrochure.htm

 
Would like to see the transient response on that. How fast can it change the frequency of the note it is outputting?

I really never understood the emphasis on ~sub-20Hz frequencies. You sort of stop experiencing those as "sound" and more like individual notes.
 
Feb 28, 2013 at 1:39 PM Post #7 of 35
Quote:
 
Would like to see the transient response on that. How fast can it change the frequency of the note it is outputting?

I really never understood the emphasis on ~sub-20Hz frequencies. You sort of stop experiencing those as "sound" and more like individual notes.

Transient response? Below 20Hz?  No need.  The transients involved are handled by other speakers.
 
It works just fine, it will handle any complex wave form below 30Hz or so, but harmonics above that are cut off, I think, at 18dB/oct at least.  
 
There's a world down below 20Hz that is heard/felt as pressure and shaking.  We just ignore it because it's impossible to do in most rooms.  I measured a healthy 7Hz out of a system with 4 HSU subs, though.  But it was a very well designed room.
 
Feb 28, 2013 at 2:08 PM Post #8 of 35
At some point it's just a speaker cone going in and out in and out. For that to make a sound, it would need to be made of steel and powered by Hoover Dam!
 
Feb 28, 2013 at 4:47 PM Post #9 of 35
Quote:
At some point it's just a speaker cone going in and out in and out. For that to make a sound, it would need to be made of steel and powered by Hoover Dam!

Did you look at the link?  It's a fan with blades that vary in pitch with extremely low frequency audio from neutral to positive or negative pressure.  It's used to pressurize or depressurize the room.  Technically, it goes down to DC, but he doesn't spec it that low.  The fan is baffled and isolated so you don't hear it running.  
 
Feb 28, 2013 at 4:59 PM Post #10 of 35
Quote:
the rotary woofer has enough acoustic output to move a open door back and forth .5” between 1 and 5Hz

Psh, that's it?
 
When I see a helicopter in a movie, I want to feel like there is really a helicopter in my room. The door should be blown right off, not moved a half an inch!
 
Really though that looks pretty cool. It would be nice to have for movies.
 
Feb 28, 2013 at 5:09 PM Post #11 of 35
Quote:
Psh, that's it?
 
When I see a helicopter in a movie, I want to feel like there is really a helicopter in my room. The door should be blown right off, not moved a half an inch!
 
Really though that looks pretty cool. It would be nice to have for movies.

Talking with the inventor, I noticed a problem.  You have to be able change the air pressure in your room.  To do that, the air has to come from and go to somewhere else, and an small closet won't do it.  It has to be a space almost the size of the theater room, preferably larger.  He told me they often back vent to the outside.  Outside the house????  Yup.  So, my next question was, how do you deal with the neighbors hearing all that XLFE?  His answer, and I quote, "Invite them over!"
 
By the way, he's in Texas, if that puts any better perspective on it.  And, in practice, attics work for the back vent too.  In the demo, in a hotel room, the drop ceiling was moving enough to shake drop ceiling crud down on all of us.  Kind of funny, amazing, and disturbing all at the same time.   It's also not a substitute for a set of subs, it's a sub-sub.  And about $18K.
 
Feb 28, 2013 at 5:38 PM Post #12 of 35
If I had that in my theater, the sound of the fan wouldn't be the problem. There walls would creak, whoosh and rattle. As it is, my sub makes strange things happen inside the walls of the room. I think back in 1952 when they built the house, the workers left their empty beer cans inside the walls.
 
Mar 1, 2013 at 5:18 AM Post #13 of 35
Quote:
If I had that in my theater, the sound of the fan wouldn't be the problem. There walls would creak, whoosh and rattle. As it is, my sub makes strange things happen inside the walls of the room. I think back in 1952 when they built the house, the workers left their empty beer cans inside the walls.

If I had that in my theater my wallet would creak, whoosh and rattle.
 

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