How low can you hear? - AVS Forum
View Poll Results: In which file did you begin to hear the tone?
10-19Hz 0 0%
20-29Hz 0 0%
30-39Hz 0 0%
10-19Hz, but I believe it is distortion. 0 0%
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post #1 of 48 Old 02-21-2011, 03:41 AM - Thread Starter
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A lot of people here are chasing lower and lower extension. Some are pouring tons of money and amplification into walls of speakers that extend to the lower single digit range. Popular wisdom says that we are feeling, not hearing, that low. But some sources, citing the Fletcher Munson curve, say that we CAN hear that low. This article from the makers of the Thigpen Rotary Woofer claims that people can perceive sound as low as 5Hz! (provided the tone is loud enough - at least 110db, as shown by their chart)

So what is going on? Are the people at this site wrong? Did they not have $10,000 to invest in creating a wall of sound?

I'm trying to conduct an informal experiment to see how low we can really hear. We have been told all our lives 20Hz, 16Hz by some sources. Some people say those of us over 30 can't hear below 30Hz. I believe this is wrong, unless somebody can explain to me what I am hearing.

Here is the test I would like you to try out. You will need a computer (if you are reading this, you're halfway there!) and a pair of headphones. Mine are Supra-aural. Circumaural would be better. I recommend not using speakers unless your setup is capable of producing frequencies down to 10Hz without melting a coil. These files are pure sine waves from 10Hz to 39Hz.

The test files can be obtained directly from RealTraps here: http://www.realtraps.com/test-cd.htm Just download the zip file. The first three files titled 10-19Hz.mp3, 20-29Hz.mp3, and 30-39Hz.mp3 are what we will be listening to.

Here is what each file contains:
NOTE: The sound file starts at the bottom of the picture, and ends at the top.

10-19Hz.mp3
1:39
10Hz to 19Hz in 1Hz increments


20-29Hz.mp3
1:39
20Hz to 29Hz in 1Hz increments


30-39Hz.mp3
1:39
30Hz to 39Hz in 1Hz increments


When I first did this test, I used Room EQ Wizard's frequency generator, started at 20Hz, and went all the way down to 10Hz. In a quiet room, I could hear each tone, all the way down to 10Hz. Now, by the time I was at 10Hz, I had to have my headphones turned up all the way, and I could barely hear it, but it was perceptible.

Using these files, and in the room I am in at the time of posting (probably a good 60db of fan noise), I start to hear a low frequency tone about 20 seconds into the 10-19Hz file. I'd estimate this to be the 12-13Hz area. To hear this low, I have to press the headphones to my ears and really listen. By the time the end of the file comes along, I don't have to press the phones against my ears any more, and I can start turning it down.

So, for those of you who would like to try this some questions:

When, and in which file can you start hearing a tone?

For those of you who who are skeptical, yet open minded enough to have tried this experiment, what are we hearing in the first two files? It sounds similar (just lower pitched) to what is in the third file which we should all be able to plainly hear.

If we are hearing some form of distortion, why does the sound not change (other than in pitch) as the frequencies increase? If what we are hearing is truly an "infrasonic" tone, then we can expect that if would be hardest to hear at 10Hz, and get progressively easier to hear as we approach 39Hz. This holds true, at least in my case.

If it was distortion, would it not be just as loud at 15Hz as at 25Hz?

So, what conclusions can we draw? Are we hearing down that low, or are we hearing some sort of artifact or distortion?
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post #2 of 48 Old 02-21-2011, 05:56 AM
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Having just jun 1/6th octave test tones, I can say I hear in the very upper range of the teens.

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post #3 of 48 Old 02-21-2011, 06:00 AM
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The best way to identify if you're hearing distortion would be to conduct the same test, but control the amount of distortion in the headphones.

An interesting thing I've observed with audiophiles is that they pride themselves in hearing details, and therefore will go to great lengths to defend the importance of that which they think they're perceiving.

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post #4 of 48 Old 02-21-2011, 06:22 AM
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From my IB sub build thread, am I really-really hearing/feeling sound at such low freq?? ,

Posted 2/3/2009:
Quote:


Just for fun I opened up REW and re-plotted the 3rd seat chart, this time extending it to as low as REW goes, 2hz.


I thought to myself, am I really-really hearing/feeling sound at such low freq??
Alright, took some picts and made some YouTube videos to prove to people this IB sub does work as low as it can go and does not tear apart.

These AE IB15's are awesome speakers!!!!
Thx Acoustic Elegance guys for superb product.



Test DVD, note the tones are encoded at -20db to "protect the innocent" from destroying their system.



YouTube Videos:
This video show my 4 speaker line array Infinitely Baffled Subwoofer speakers up close, you can see 10hz subwoofer cone movement action .
I'm getting 80db, and this signal was attenuated -20db on the recording, so plenty of low freq headroom. Capable of 100db!!
&fs=1" width="644" height="390">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&fs=1" />[ATTN POSTER: YouTube Insert Error: Something went wrong. Please make sure you added the video correctly. Click here to see how YouTube videos should be embedded. There could also be a technical issue that's not your fault. Click 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" target="_blank">here to view the video on YouTube's site. If this link doesn't work, you did something wrong.]

This video show my 4 speaker line array Infinitely Baffled Subwoofer speakers up close, you can see 6hz subwoofer cone movement action .
I'm getting 77db, and this signal was attenuated -20db on the recording, still some ultra low freq headroom.
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This video show my 4 speaker line array Infinitely Baffled Subwoofer speakers up close, you can see 3hz subwoofer cone movement action.
Yes, that's not a typo, 3hz. Just an academic study, geeky to see them moving so slow.
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This video show my 4 speaker line array Infinitely Baffled Subwoofer vibrating my 130" DIY Ht screen - hard to see via handheld camera in video mode but it did vibrate, so definitely the 10hz pressure wave is there, real.
There are all sorts of resonances/other in my basement @ 10hz, for instance my walkout french doors pulse in/out @ 10hz.
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I definitely could hear into the mid-low teens, and feel the bass down to 10hz in my body.

For reference, I'm close 48 years young...
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post #5 of 48 Old 02-21-2011, 06:22 AM
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I guess I can hear down to 10 Hz. With the volume all the way up I can hear it as soon as it starts. No sure what the dB level is.

Dumb enough to spend lots of cash on this junk!
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post #6 of 48 Old 02-21-2011, 07:22 AM
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I bet I can hear to about 18hz or so but everything below is perceived. 5 Hz sine waves will flex the wall and pressurize the room so I am not sure if I am hearing the wave itself or the effects of the wave. I am guessing it is the latter.
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post #7 of 48 Old 02-21-2011, 07:53 AM
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Quote:
Originally Posted by DanLW View Post

A lot of people here are chasing lower and lower extension. Some are pouring tons of money and amplification into walls of speakers that extend to the lower single digit range. Popular wisdom says that we are feeling, not hearing, that low. But some sources, citing the Fletcher Munson curve, say that we CAN hear that low.

This is an excellent very useful thread Dan.
I used my little old cheap headphones when I did this test. I could hear what I will describe as vibration at 13 hz although there was something going on a little lower. But in terms of what I will describe as a change in tone or pitch, I didn't hear any clear distinction until roughly 18hz where incrementally the sound changed. I can't say that it was sound that I would describe as usable. There was nothing that would allow me to use my dance moves at those lower frequencies. I feel those vibrations would be useful in movies. When I did the test using a subwoofer that is not rated very low, I heard tonal change at roughly 24hz and the port air increased significantly at 30hz. I've read that their are some instruments that will play quite low, but I don't listen to that type of music in general. I did have to turn the volume up louder then normal, in order the here the changes in the lower samples finally decreasing volume after roughly 28hz. I'm 55.5 years young.
Again, great educational thread, Good Luck
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post #8 of 48 Old 02-21-2011, 09:36 AM - Thread Starter
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Quote:
Originally Posted by cbrett View Post

. There was nothing that would allow me to use my dance moves at those lower frequencies. I feel those vibrations would be useful in movies. When I did the test using a subwoofer that is not rated very low, I heard tonal change at roughly 24hz and the port air increased significantly at 30hz. I've read that their are some instruments that will play quite low, but I don't listen to that type of music in general.

There is one song that I really like with heavy infrasonics. It's called "Bass I Love You" by Bassotronics. I would LOVE to hear that song on notnyt's newly finished wall of sound!

Here is a spectogram from part of the song...


The lowest bump is centered at 7Hz... Bass, I love you! It's this sort of thing that makes me want to seriously consider some DIY subbage...

The other thing I would like to hear is a live organ playing a song involving those 16Hz notes.
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post #9 of 48 Old 02-21-2011, 10:25 AM
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I can hear the tones from the very beginning with my headphones turned up all the way.
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post #10 of 48 Old 02-21-2011, 10:50 AM
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The ability to discernibly "hear" very low frequencies, is as much of a function of SPL as it is frequency.

If I recall correctly, Bruce Thigpen has demonstrated that he can make sound loud enough to be audible down to about 3-4hz with the his rotary woofer. Being mindful of the EL curves, approx. 110db is required for the threshold of audibility at 5hz. That said, 120db of 5 hz isn't relatively loud, as it's about 10db above audibility. Additionally, Thigpen demonstrated that 4Hz, 8Hz and 16Hz signals, could be delineated from one another.

Realistically, anyone who's ever had a very capable sub in the infra range, knows that misc. room noises from rattles and so forth can be problematic. I remember a product called "The Rattler", a vari-freq generator that aided in finding each item in a room that sympathetically excited to a given frequency.



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post #11 of 48 Old 02-21-2011, 11:10 AM
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Quote:
Originally Posted by DanLW View Post

There is one song that I really like with heavy infrasonics. It's called "Bass I Love You" by Bassotronics. I would LOVE to hear that song on notnyt's newly finished wall of sound!

The lowest bump is centered at 7Hz... Bass, I love you! It's this sort of thing that makes me want to seriously consider some DIY subbage...

The other thing I would like to hear is a live organ playing a song involving those 16Hz notes.

Man, that's some low bass. I just finished listening to it. The cheapie headphones didn't image much of what was going on in the background of that tune, but when I heard it on the subs, it was indeed amazingly low, and I very nice bit of music too.
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post #12 of 48 Old 02-21-2011, 11:28 AM
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Quote:
Originally Posted by DanLW View Post

So, what conclusions can we draw? Are we hearing down that low, or are we hearing some sort of artifact or distortion?

You're hearing harmonics, which are created by the speaker/headphones, assuming there are non present in the original signal, and that's a very slim possibility as well. Below roughly 20 Hz, give or take a few Hz with different individuals, sound travels through your head, and the pressure on both sides of the eardrum is the same. No movement of the eardrum means no sound is heard. Your body can feel the vibrations, but your ears hear the harmonics. As for distinguishing tone/pitch, that only occurs roughly an octave higher. If you listen to a pure unadulterated sine wave between 20 and 40Hz or so you can't distinguish pitch; it's the harmonics that give that ability. That's not a problem, as nothing we listen to consists of pure unadulterated sine waves. Harmonics are always there.

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post #13 of 48 Old 02-21-2011, 12:31 PM
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there's a lot to read, so I'll just post my initial responce now and maybe read and repost later, bt currently I can hear to about 15Hz with my system and feel down (perceive) to 3-4Hz. In my car when another car wizzes past I can perceive about 2Hz.

If I win the lotto and I make a wall of 40 22" IB3's ported/ininite baffle, maybe I will actually be able to hear 8Hz and perceive 2Hz?
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post #14 of 48 Old 02-21-2011, 02:44 PM - Thread Starter
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Quote:
Originally Posted by FOH View Post

Realistically, anyone who's ever had a very capable sub in the infra range, knows that misc. room noises from rattles and so forth can be problematic. I remember a product called "The Rattler", a vari-freq generator that aided in finding each item in a room that sympathetically excited to a given frequency.

Several years ago, I used the very files posted in the initial post to manually chart my room's bass response. (This was before I got REW) It was interesting to see what rattled at what frequency. As the sweep would slowly and steadily go up, first a door would rattle then stop as the frequency went by it's resonance, and then a cupboard would rattle, then a picture frame. And this wasn't too terribly loud either... I think either 80 or 85db.

So this CD can be good for isolating those rattles, also!
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post #15 of 48 Old 02-21-2011, 02:49 PM
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This.

Quote:
Originally Posted by MKtheater View Post

I bet I can hear to about 18hz or so but everything below is perceived. 5 Hz sine waves will flex the wall and pressurize the room so I am not sure if I am hearing the wave itself or the effects of the wave. I am guessing it is the latter.

And this.

Quote:
Originally Posted by Bill Fitzmaurice View Post

You're hearing harmonics, which are created by the speaker/headphones, assuming there are non present in the original signal, and that's a very slim possibility as well. Below roughly 20 Hz, give or take a few Hz with different individuals, sound travels through your head, and the pressure on both sides of the eardrum is the same. No movement of the eardrum means no sound is heard. Your body can feel the vibrations, but your ears hear the harmonics. As for distinguishing tone/pitch, that only occurs roughly an octave higher. If you listen to a pure unadulterated sine wave between 20 and 40Hz or so you can't distinguish pitch; it's the harmonics that give that ability. That's not a problem, as nothing we listen to consists of pure unadulterated sine waves. Harmonics are always there.


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post #16 of 48 Old 02-21-2011, 02:53 PM
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Quote:
Originally Posted by DanLW View Post

The lowest bump is centered at 7Hz... Bass, I love you! It's this sort of thing that makes me want to seriously consider some DIY subbage...

What sub(s) are you currently running?


Quote:
Originally Posted by Nardokor View Post

I can hear the tones from the very beginning with my headphones turned up all the way.

Doesn't this all depend upon the quality of the playback source as well? Can your equipment (ie receiver, laptop, amp, speakers, headphones) drop down and play these tones? If so, what's the slope look like down there on your equipment?


Quote:
Originally Posted by Bill Fitzmaurice View Post

Below roughly 20 Hz, give or take a few Hz with different individuals, sound travels through your head, and the pressure on both sides of the eardrum is the same. No movement of the eardrum means no sound is heard.

Bill - Does this apply to someone using headphones as well? Considering they can reproduce the signal accurately. How does the wave cancel out with the use of quality cans?


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post #17 of 48 Old 02-21-2011, 04:38 PM
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Quote:
Originally Posted by dbldare View Post

[b]Bill - Does this apply to someone using headphones as well?

It does.
Quote:
How does the wave cancel out with the use of quality cans?

The same as it does with speakers. Acoustically speaking your body is totally permeable with 60 foot and longer wavelengths, as is just about anything and everything.

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post #18 of 48 Old 02-21-2011, 04:46 PM
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For Bill and others.....

There was a study done to prove whether or not infrasound is heard and not felt. They used people with normal hearing and as a control, deaf people (people that could only 'feel' sound). Guess what? The people with normal hearing needed their normally functioning cochleas to hear infrasound at lower levels. The deaf people required more spl to 'feel' it.

It is of note that I do not remember the distortion figures for their sound sources, so it may very well be that the test subject's cochleas were hearing harmonincs.....

Wish I had saved a copy of the article....

Your ear is still the primary sensory organ for ANY sound. It is incredibly sensitive to air pressure changes, regardless of frequency. More so than almost any other organ save maybe pacinian corpuscles, which also detects pressure, but usually tactile pressure.

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post #19 of 48 Old 02-21-2011, 05:19 PM
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I'm with bill on this. I definitely have a system that will get down to 5hz at ridiculous levels without distortion. Slightly below 20hz, it's all feeling and not hearing. I do feel the pressure in my head on the lower stuff slightly, but it's definitely not the same as hearing a note.

Most people claiming to hear 10-19 will just be hearing harmonics.

Feeling it is the fun part though. I didn't go crazy building a wall of speakers to hear < 20hz, it's the tactile sensation you get.
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post #20 of 48 Old 02-21-2011, 06:25 PM
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Quote:
Originally Posted by Bill Fitzmaurice View Post

Below roughly 20 Hz, give or take a few Hz with different individuals, sound travels through your head, and the pressure on both sides of the eardrum is the same. No movement of the eardrum means no sound is heard.

If the pressure on both sides of the eardrum is the same for frequencies below 20Hz, then why do I have to equalize the pressure in my ears whenever I go up/down many floors in an elevator, or take off/land in a plane? That's definitely happening at less than a 20Hz rate.
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post #21 of 48 Old 02-21-2011, 07:39 PM
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Quote:
Originally Posted by stereo2.0 View Post

why do I have to equalize the pressure in my ears whenever I go up/down many floors in an elevator, or take off/land in a plane? That's definitely happening at less than a 20Hz rate.

You're kidding, right? But in case you're not...


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post #22 of 48 Old 02-21-2011, 08:06 PM
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[quote=Bill Fitzmaurice;20042495]You're kidding, right? But in case you're not...

Actually, I'm not.

If I understand your explanation correctly, you're suggesting that sound frequencies above 20Hz will vibrate the eardrum while frequencies below 20Hz will not, and yet when you apply a gradual change in pressure (like an altitude change) the eardrum suddenly becomes displaced enough to require the equalization of pressure by yawning/swallowing/chewing gum etc.

So are you stating that some sort of physiological notch filter is in place to stop all eardrum movement for frequencies above DC but below 20Hz?
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post #23 of 48 Old 02-21-2011, 08:42 PM
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Sound displaces the eardrum and then lets it return to equilibrium. Air pressure exerts a constant pressure until you equalize it by opening the eustation tube. The two are totally different.

Dumb enough to spend lots of cash on this junk!
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post #24 of 48 Old 02-21-2011, 10:08 PM
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OK, I understand and agree with you for DC type changes, but I was talking about >DC type frequencies. I'm not trying to sound dense or be flippant here, but aren't VLF signals the same as rapid air pressure differences?

Example: Imagine taking an elevator ride to the 50th floor. I think everyone could agree that the pressure difference could be enough to require opening the eustation tube to regain equal pressure if one decided to stay on that floor. But now imagine the elevator doesn't actually stop at the 50th floor but continues to oscillate between the ground floor and 50th floor in a sine wave type motion.

My argument is that your ears will probably deflect by an equal amount due to the pressure changes no matter what the frequency of oscillation is. (This is a thought experiment so please try to ignore the repercussions of being slammed against the elevator roof 20 times a second)

I think that if your eardrum is displaced by Xmax on the 50th floor at 0.01Hz, then it will also be displaced by Xmax at 1Hz, 10Hz or 20Hz as well. I can't see how a skull can be permeable for frequencies below 20Hz but suddenly change to a complete barrier at VLF (elevator ride) frequencies.

I think the eardrums will change their position and follow the pressure changes all the way from 20Hz down to DC without becoming immobile somewhere in between. However, our ability to discern those lowest frequencies will diminish into inaudibility unless the amplitude becomes high enough to feel it.

I think "DanLW" was trying to determine what that lowest audible frequency was before it became a tactile sensation. (I wish "maxmercy" could find that document he read about earlier)
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those results were likely generated using headphones and test signals. my headphones (sony) are rated to around 16hz. about the lowest that i can hear through them is around 20hz using spectrumlab to ensure distortion (in signal) is down 50-60db or more.

at some spl, all changes in pressure can be perceived. maybe it shifts from the eardrums to the semi-circular canals at some point or to something else, but it can be perceived. i'm sympathetic to those who are building systems that are capable to 8hz or so, but i also think that it is more important to first nail the 25hz+ region with big spl then work your way on down as budget allows.

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post #26 of 48 Old 02-22-2011, 03:14 AM - Thread Starter
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Lots of interesting conversation here about the topic. So, most of us are hearing "something" in the 10-19Hz file. But the question is whether or not we are hearing harmonics, or the real deal. If we are hearing harmonics, how come the "sound" of the waveform doesn't change if I start at 40Hz and gradually dial it down to 10Hz in REW?

Quote:
Originally Posted by dbldare View Post

What sub(s) are you currently running?

dbl

Currently at home I have a broken Klipsch RW-12D. (apparently the power supply cares about the polarity of hot and neutral, as it died after I plugged it into a 220-110V transformer backward) I plan to get it fixed, but there is no way it would ever begin to think about hitting the lowest notes in Bass I Love You. Using my headphones I can maybe hear the 16Hz note, but everything else has to be turned up loud for that to happen.

Once I get back home, I'll have to try it with my Sennheisers.

I was going to get a pair of PB-13 ultras and run them sealed. They are supposed to play flat to 10Hz in sealed, taking room gain into account. So they should hit the 16Hz note fine, but not sure if I would percieve the 7Hz. But I found out 155lbs is too heavy to ship to an APO. So now I'm toying with the idea of a couple DIY cubes with LMS-5400s. I'm communicating with partsexpress to see if it can be shipped to an APO. The motor is 68lbs and shipped separately... not sure how much weight the packaging adds...
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post #27 of 48 Old 02-22-2011, 03:22 AM
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Quote:
Originally Posted by kryptonitewhite View Post

there's a lot to read, so I'll just post my initial responce now and maybe read and repost later, bt currently I can hear to about 15Hz with my system and feel down (perceive) to 3-4Hz. In my car when another car wizzes past I can perceive about 2Hz.

If I win the lotto and I make a wall of 40 22" IB3's ported/ininite baffle, maybe I will actually be able to hear 8Hz and perceive 2Hz?

You have one of those crazy loud systems in your car? I hope you don't play it that loud going down the street. That is totally disrespectful of other people. I know I just want to kill those kids with the super loud subs. Nobody else is interested in listening to your crap but you.

Dumb enough to spend lots of cash on this junk!
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post #28 of 48 Old 02-22-2011, 07:35 AM
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Quote:
Originally Posted by DanLW View Post

Lots of interesting conversation here about the topic. So, most of us are hearing "something" in the 10-19Hz file. But the question is whether or not we are hearing harmonics, or the real deal. If we are hearing harmonics, how come the "sound" of the waveform doesn't change if I start at 40Hz and gradually dial it down to 10Hz in REW?



Use your test tones again, but connect a test microphone up to the input of your PC. Any microphone will do for this test. Place the microphone near the headphones. Perhaps place the mike in the headphone, and place a towel over the mike and the headphone to seal it somewhat. Then use SpectrumLab same as was done earlier.

SpectrumLab shows that the tone generator is fine. No harmonics that I can see. Now use SpectrumLab to evaluate how the headphones are distorting the original tone. Test each tone one frequency at a time. For example is a 20Hz tone clean on playback, or are there multiple harmonics?
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post #29 of 48 Old 02-22-2011, 11:26 AM
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Quote:
Originally Posted by maxmercy View Post

Wish I had saved a copy of the article....

Is this it? http://www.canwea.ca/pdf/talkwind/Lo...Generators.pdf

On page 24 it mentions a test with deaf and hearing persons, but only at 6Hz and 115dB.
Elsewhere it states that frequencies from 2Hz and up can actually be heard if not felt.

Although it was interesting to browse through, it seemed to have an agenda to disrepute any claims of infrasonic disturbance for those living near wind turbines. I've never been close enough to a wind turbine to have an opinion, but has anyone else heard them up close to comment on their infrasonic output?
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post #30 of 48 Old 02-22-2011, 01:20 PM
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Quote:
Originally Posted by stereo2.0 View Post

but has anyone else heard them up close to comment on their infrasonic output?

I haven't. OTOH I can walk out to my backyard, take a read with my pocket RTA and see a 50-55dB reading at 20Hz; the source is vehicle traffic on a highway a mile away. I can't hear it, but I know it's there because the RTA mic can. I don't imagine wind turbines would be any more offensive. OTOH on that same highway I can read 75dB at 500Hz if a loud piped Harley passes by, and that is quite offensive. My only satisfaction lies in knowing the jerk riding it will eventually go deaf from doing so.

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