3Hz! (1 Viewer)

[Scott*E]

I've heard that the LFE channel on a 5.1 soundtrack goes all the way down to 3Hz. The lowest I've seen powered subwoofers go down to is 20Hz. Does any one know where I can find a powered subwoofer that goes down to 3Hz?

 

[Phil Iturralde]

Here's one!
Phil

 

[BrianWoerndle]

The human ear can only hear from 20-20k hz, so it it pointless to go that low. It is possible, but not realistic.

 

[Jason Wilcox]

yeah you won't be able to hear it....but i'm guesin you'd feel it in your gut....in a bad way

 

[Cam S]

I've heard that 5hz and lower can make you lose control of your bowel movements! Any truth to this???

 

[Brian Bunge]

I wouldn't say it's pointless. It would be expensive though!
Brian

 

[Mark Austin]

I would say it would be EXTREMELY pointless on two counts. First information at 20hz is very scarce in most movies, in the best cases maybe 10-15 seconds of a two hour movie, maybe. In most movies it's around 5 seconds or less. The information at 3hz would be considerably less than that. Like maybe 1 second in one in every 30 movies. Second would be cost. Unless you have the baddest of the bad HT's, your money would be far better spent on other components in the system.

 

[John F. Palacio]

"I've heard that 5hz and lower can make you lose control of your bowel movements! Any truth to this???

As a matter of fact there is! I can be higher than 5Hz. It just needs to be loud enough. There was name for it in the 70's. It was called the Disco Dump.

I forget what the biomechanics of it are, but I guess a few poor souls discovered it the hard way in some loud Discotheque.

Lesser SPL's will make you loose your balance. I did experience loss of balance while playing in a band in front of a bass stack.

Moved away before it got to the second stage!

 

[Jeffrey Forner]

Quote:

First off, let me say that I do agree that it's probably unnecessary to look for a subwoofer that can produce a 3 Hz tone since it's so rarely used, but I would strongly disagree that it's "unrealistic" to have that can go lower than that.

Believe me, there's more than a few seconds of sub-sonice LFE in The Phantom Menace or the DTS version of The Haunting. And just because you can't hear it doesn't mean you can't feel it. Believe me, once you have a sub that can go that deep, you'll appreciate it when those ultra-low bass notes hit all the more.

 

[Bill_D]

There was name for it in the 70's. It was called the Disco Dump.

Also commonly referred to as a brown note.

 

[Brian Bunge]

There's also a guy around here that was pissed off about the Crown K2 amps having an 8Hz subsonic filter. He stated that he wanted to experience the full impact of the canon shots in the 1812 Overture, which I believe extends down to 5Hz or so. So while you may not have as lofty requirements that doesn't mean there's absolutely no reason why anyone would want to do it.

I don't agree with adding $10K in mods to a $15 Honda Civic, but I wouldn't call it pointless. After all, you'd end up with a Porsche 911 Killer for $25K!

Brian

 

[BrianWoerndle]

But why build a Porsche killer if you will never be running it that fast because it is aganist the law?
The same reason you don't need a speaker to go down to 3hz. It will so rarely be used does it justify the cost?

 

[Andrew Santos]

I don't agree with adding $10K in mods to a $15 Honda Civic, but I wouldn't call it pointless. After all, you'd end up with a Porsche 911 Killer for $25K!

i highly doubt that. 10k would not make a 0-60 in 8s civic go 0-60 in 5s or less.

 

[Lew Crippen]

Regardless of whether you buy the Porsche or build the Porsche killer, driving here in Dallas on the LBJ, you will pretty much go as fast as the VW…and no faster.

 

[Cam S]

Haha, I own a Honda, and I'll have to disagree with it being able to beat a 911. It would take a serious amount of turbo boost to be able to compete against the 911's in straight line performace. Even then it's not going to corner near as good with a serious amount of suspension work. I'll admit it, honda's are dam slow, I mean they ARE economy cars, not sports cars.

 

[Chris PC]

I think it is un-neccesary to go to 3 or 5 hz. I think 10 hz is the lowest you really need in terms of how it costs to go lower, the fact that you'll only feel it and not hear it, and the fact that most movies don't have program material at 5 or 3 hz. I think my in room probably goes down to a realistic 12 to 16 hz and thats fine with me

 

[Brian Bunge]

I've heard of some turbo charged Civic's dusting some highly modified Mustang GT's. Maybe Porsche Killer is a bit extreme, but it's highly possible to get the same cornering capability with some of the adjustable suspension kits and the right tires.
Either way, the point is, there are those individuals that are willing to push things to the extremes. While it may not be practical for the average consumer, I still say if you want that level of performance then go for it. Just don't expect to do it with any commercially available sub.
BTW, the guy that I mentioned above built 4 18" ported subs and also uses dual Buttkickers in his HT. He's what I call extreme.
Personally, I'm just happy knowing that I can destroy a $25K Krell MRS sub for less than $3K!
Brian

 

[Scott*E]

It's not totaly pointless to go below 20Hz. It's true that the human ear can't HEAR anything below 20Hz, but with the right subwoofer and enough power you can definatly FEEL it.

 

[Tim Hoover]

Actually, the 20Hz hearing threshold is just a rough guideline. Like all physical senses, the exact amount varies from person to person. When I last had my hearing tested two years ago, I responded to signals from around 18Hz up to around 23kHz.

As further proof, on the THX Optimode bass frequency sweep, I can CLEARLY hear the test end at its low limit of 20Hz.

 

[Mark Seaton]

Someone please do a search and pull up the last thread where I went through all this audio folklore.

Tim is right that there is no absolute frequency below which we can't hear. The threshold of audibility just gets higher and higher. Our designer Tom Danley had produced audible output down to the 5Hz range outdoors for the NASA project where he was contracted to produce a sonic boom to the front of a mock up home and a few other applications. The Discovery Ch special which showed this "wall of sound" gets replayed every so often. In a concrete constructed test room very high output was achieved to about 2-3Hz.

Now, as for the usefulness of achieving the output, I strongly contend that it is worthwhile, albeit somewhat expensive at the moment. I also have a sub that will produce 105-115dB at 1m in a room to below 10Hz. This sub was measured in room to have flat response to 5Hz. I would argue two main benefits. First, precussion instruments can certainly have energy down to the 10Hz range and can only make the reproduction of the sound more accurate, as this was a part of the originally created sound. Secondly, there is the matter of phase response where response to such low frequencies moves the phase and group delay changes from the resonance and roll-off to well below the majority of content. Our ContraBass is basically flat down to 14-16Hz. If 20Hz was all that mattered, there would be no percieved difference between the ContraBass and a sub which responds much lower. I can tell you there is a difference.

Now we get back to the electronics... Where exactly did anyone hear that the LFE channel has response to 3Hz? I would be very interested in this. That said, the best digital processors out there limit deep bass output to at best 5Hz due to the DSP computations which produce low frequency errors. Once you do start to look below 20Hz, you have to check your electronics and see what the entire system can produce, not just one part of the system.

We should remember that through the years the "accepted" required range has continually extended lower as technology allowed us to reproduce it. We really can't evaluate its value until you have a capable means to produce it. No, the claims of Bag End and REL don't cut it unless you have LOTS of them coupled together.