How much will I miss if I "only" go down to 25Hz? - Page 2

That can be said for about anything. That really is getting away from the OP's original question. There's a difference between it being used less frequently (if that's your thing), and not being able to reproduce any of it.

I think Open Range has one of the better thunder scenes I've seen.

Reality check: Look at an equal loudness chart. Even if you have speakers capable of reaching below 25Hz they need to be able to reach 110dB plus levels to hear it. That means a lot of speakers, a lot of power, and no neighbors within a quarter mile.

Bill,

I've seen the equal loudness curves ad I agree about "hearing" infrasonics. However, I've never seen anything about the levels needed to "sense" infrasonics. Do you know if this has ever been defined?

Craig

I don't need to hear it, I want to feel it.

Below 14 hz and most human hearing can't detect it anyway.

My first sub was a DefTech ProSub 200TL: 26Hz @ -3dB. I liked it a lot. Then I had the chance to demo an Energy S10.3 in the same space: 21Hz @ -3dB. I heard and felt stuff I had never experienced with my DefTech sub.

It wasn't long before I had an SVS PB10-NSD in my set-up. And I don't ever want to go back to a sub like my DefTech.

I've heard something similar but the number quoted was 100db.

and it's then you realize you've peed yourself again.

I can play a 25Hz tone at 100dB and not hear anything; if not for my sound meter I wouldn't be aware there was any sound. But that's using a speaker capable of 100dB at 25Hz with less than 2% THD, so it's a clean tone devoid of harmonics, which very few speakers are capable of. Most users who think they're hearing 25Hz or lower are actually hearing 2nd and 3rd harmonics.

True. Or it's just because you're old and your hearing sucks.

Before before getting an SMS-1 I use to use a BFD and sine waves to EQ the sub and I could hear the sine wave down to 16Hz. Below that the room just shook like crazy but there wasn't any sound other than the walls making noises. It's kind of creepy how the walls creak and groan, but there isn't any sound at all from sub or at least not sound that I could hear. I didn't usually go higher than 90dB on the SPL meter but I could here the sine wave at 16Hz..

Wow you really can't hear lower than 25Hz? Have you spent a lot of time listening at high volumes and damaged your hearing?

I know that about harmonics. I'm saying I heard the number was 100db rathet than your 110db.

I don't know how your source came up with that figure. I measured it. This was outdoors, so the result was not corrupted by the pressurization of a room. I didn't say that. I said my threshold at 25Hz is 110dB, which is pretty much average. I can't hear anything much below 15Hz, but no one can, for a variety of reasons, all of them biological. If the room is small enough and the system powerful enough to pressurize it you can feel below 15Hz or so, but you can't hear that low.
Edited by Bill Fitzmaurice - 1/30/13 at 7:18pm

True except I always wear my OOPs I Crapped my pants so I am safe.

Thanks for clarifying that Bill I thought you had some serious hearing damage. Good to know your hearing is working as it should.

Quoted for truth

OK, I think it's time someone answered the OP's question directly without all this beating around the bush.

24hz.

Interesting discussion with no comparison to the theater experience. Also, no talk about THX reference level and standards. There are some really good subs that can shake things off walls and blow your hair across your face. How often does this happen at the movies? In other words, this is not what the studio engineers intended, it is not necessarily bad. The op ask what will he be missing, not much if he compares it to going to the theater. I feel many HT setup can provide an experience superior to the live theater just without the massive screen.

It does not matter what real theaters do because there are lots of under 25hz on our disc that we buy. It is up to the individual to decide what he wants to playback. Again, real life sounds are uncompressed, dynamic, and full bandwidth. They don't have limiters, filters, etc... The best movie experiences as sound goes are the recordings that follow suit.

There aren't any. Well, not totally, you can find the odd symphonic recording that's not compressed or processed, but they're rare. Compression and every other function that DSP is capable of is used, liberally, on virtually every DVD made.

My bad... I meant to accompany that picture with:

"This is what you are missing if you cut youself short at 25Hz."

IMHO, having a ULF capable system really expands the horizons...

I'm not sure what the theater experience has to do with what is encoded on the disc. My local theaters have zero LFE, so I guess I should just sell my sub and run without one.

Since he didn't ask what he'd be missing compared to going to a theater, why bother comparing it to a theater? I've watched movies at the theater where the sound was far too loud, distorted, bloated and/or muddy. Personally, I prefer not to enjoy this type of "theater experience" at home.

YMMV, of course.

Food for thought: Hearing at low and infrasonic frequencies

This diagram offers results from multiple investigations covering frequencies at and below 20 Hz(quoted from the above link).

I really enjoyed those links man! Thanks.

New goal... 130db @ 2Hz.

Testing shows that anything less can't be "heard" down that low.

Sounds fun.

So check this out, I would almost want to use that graph to refine my reference volume. I mean, what is the point of being "flat" to 3Hz if it takes about 125db for someone to gain any real benefit? So you could measure to reference (115db in the sub category as defined by THX IIRC), but follow that curve from about 6Hz and below to ensure a perceived benefit is realized.

I shall dub it the:

ULF Perceived Benefit Rule

There's the rub, and why getting yourself all wet after looking at a chart that shows a lot of content below 15Hz on a DVD doesn't make a lot of sense. If you did manage a 125dB output at 3Hz you'd do structural damage to your house. Really. Guys using my THTs, which don't go nearly that low, have not only cracked drywall, they've cracked concrete foundations. That chart is actually optimistic. To know the actual sensitivity you need speakers or headphones capable of reaching those levels with very low THD specs, otherwise the results are corrupted because the tester is hearing harmonics, not the fundamental. Speakers/phones with that capability are extremely rare.
Edited by Bill Fitzmaurice - 1/31/13 at 2:49pm

This is the author's commentary about the data sets used in the graphs, they agree:
"It is obvious from [Figure - 1],[Figure - 2],[Figure - 3] that differences between investigations exist. However, one should have in mind that the data are obtained in a period of 70 years with very different techniques. Not surprisingly the largest discrepancies are found in the low and infrasonic frequency region, because it is much more difficult to produce the stimuli needed for this region. The demand on higher sound pressure levels with less harmonic distortion (due to the steep slope of the threshold curve) are difficult to meet as the production of higher sound pressure levels usually causes more harmonic distortion. Other differences between investigations can be found, e.g. in background noise level, sound field, subjects (number, age, selection process), psychometric method, instruction of the subjects, whether mean or median threshold is reported, and number of repetitions."

I just want the infrasonics for the weight and feel of it. Like I mentioned before with the truck or any heavy vehicle driving by, without them you would miss some real effects that happens in real life. Of course, we also have to hope they record those events and don't filter them out. That is another story! If the truck passed by and I felt only the chest vibrate, hair tingle without the shiver, shutter, shaking of my desk then I would not care for the lower stuff. I have owned only 3 sub systems that had a similar effect during movies. I could have had 5 but with a sealed system one must add a low shelf or some kind of boost down low and I only did that with my last two(one is current). I did that with only 2 sealed systems and the Danley DTS-10's did it naturally without any boost but they needed more EQ up top.

Exactly. Finding a speaker that can even get to 125dB at 3Hz is very difficult. Finding one that will do so with low THD, virtually impossible. A Danley Matterhorn might, and I'm quite sure none of the above testers had access to one.