Talk:Mains hum

Physics Start‑class Low‑importance

	Physics portal This article is within the scope of WikiProject Physics, a collaborative effort to improve the coverage of Physics on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.PhysicsWikipedia:WikiProject PhysicsTemplate:WikiProject Physicsphysics articles
Start	This article has been rated as Start-class on Wikipedia's content assessment scale.
Low	This article has been rated as Low-importance on the project's importance scale.

Professional sound production Start‑class Mid‑importance

	This article is within the scope of WikiProject Professional sound production, a collaborative effort to improve the coverage of sound recording and reproduction on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.Professional sound productionWikipedia:WikiProject Professional sound productionTemplate:WikiProject Professional sound productionProfessional sound production articles
Start	This article has been rated as Start-class on Wikipedia's content assessment scale.
Mid	This article has been rated as Mid-importance on the project's importance scale.

Mains Hum

I've just searched for "mains hum" on Wikipedia and not found it. Most people know what it sounds like but I wonder if someone could relate it in terms of noise colour(color) if possible? --Douglas 21:14, 4 Jun 2005 (UTC)

It's not noise. It's mostly a big sine wave, with small harmonic components. - Omegatron 21:28, Jun 4, 2005 (UTC)

Technically, it is noise: it's an unwanted signal. It could also be called a color of noise since it has a very specific spectrum: 50/60 Hz plus harmonics. The closest I find is black noise.

And it's dangerous. You should not expose yourself to eh.. to this kind of hum. It will make you eh eh ... eh stupid.

As to the question of mains hum, I know of no article covering it. I see alternating current has a short blurb about it (do a page search for "hum" and you'll find it). Cburnett 06:48, Jun 5, 2005 (UTC)

Now that I know something more technical about it (thank you), I've included it on the page. Did some formatting to, to make the article easier to read. --Douglas 14:40, 6 Jun 2005 (UTC)

I know I saw something about this in an unrelated article, something about you squeeze the iron core of the transformer one way and it squeezes out perpendicularly...I can't quite remember the name of the article (I'll have to look). RJFJR 15:02, Jun 6, 2005 (UTC)

Magnetostriction - Omegatron 15:14, Jun 6, 2005 (UTC)

I really don't think it belongs here, though, as it is not a color of noise. I'm not sure how to explain this better...

All the other examples can be thought of as white noise that's been filtered. Mains hum, instead, is specific frequencies. It's only the same because it's an "unwanted signal". The definition of "noise" used in this article is more specific than that. - Omegatron 15:24, Jun 6, 2005 (UTC)

I was coming from writing an article (on another Wiki) about amateur sensory deprivation, in which white noise, pink noise and mains hum play a part. This is the closest article my search for some information on just what mains hum is, led me to. I really don't care if it belongs elsewhere but I do feel it belongs somewhere - surely not it's own page and this page already has an 'unofficial' section to it. I'll leave it to those who know more about this stuff than I but please make sure it's somewhere for those who want to search for it in future - and I'd suggest at least a link from this page. --Douglas 20:58, 6 Jun 2005 (UTC)

"Mains" is not a term used in the United States. I removed as much reference to that term as I could because I think everyone understands what "electricity" and "AC power" are, but I could be wrong. It also reads better, because is mains plural or singular? Well, it's both, which is cute, but doesn't make well for readability when you're unfamiliar with the term. I don't mean to be standoffish to whoever changed it back, I just want to let you know that us dumb Americans don't know what a mains is (water comes from a water main (singular), but our electricity is transported by "power lines"). If the terms I've chosen are not at all used in the UK, maybe a third option is a better choice. --Eideteker 05:09, 29 April 2006 (UTC)[reply]

Yeah dont the Americans use the term 'power frequency hum' or suchlike?--Light current 21:06, 18 June 2006 (UTC)[reply]

I don't even know what we call it, if we have a word for it at all. :-) I've started calling it "mains" myself, when needed. We say "plug it into the wall" or "power line transformer". "Power line" is the closest I can think of, but doesn't really apply to the wiring in a house. — Omegatron 00:42, 19 June 2006 (UTC)[reply]

Could this article be renamed to somthing along the lines of... Alternating Current Hum or just AC Hum? I have worked with electronics for a long time and the exact reasoning of this noise intrigued me, I imagined it had something to do with electromagnetic fields causing whatever its traveling through to move. - Weylin Stoeppelmann

As far as the hum, I've always referred to it as "60 cycle hum". I won't make any claims that this is in any way a US standard, but I can pretty much say that "mains" used in regards to electricity is pretty much non-existent. Over here, mains refers to large water delivery pipes.Wschart (talk) 16:38, 1 January 2011 (UTC)[reply]

"Electric hum around transformers is caused by stray magnetic fields causing the enclosure and accessories to vibrate"- Should it be called acoustic hum? It is clearly audible! chami 12:39, 6 March 2016 (UTC) — Preceding unsigned comment added by Ck.mitra (talk • contribs)

"the fundamental "hum" frequency will be twice the electrical frequency. Additional harmonics above 100 Hz or 120 Hz will be caused by the non-linear behavior of most common magnetic materials" but the power spectrum you show on the right clearly suggests that this is not so. Strange! chami 12:42, 6 March 2016 (UTC)

Proposed Move

I Propose that this be moved to electric hum, which is more representative of a worldwide view. - SigmaEpsilon → ΣΕ 21:02, 22 October 2006 (UTC)[reply]

Maybe, but "electric hum" isn't a term that anyone actually uses. There is probably a better term. — Omegatron 20:41, 15 December 2006 (UTC)[reply]

I'm fine with the name, but if anything else: AC power hum is my alternate choice. +mwtoews 08:34, 8 February 2007 (UTC)[reply]

Anti-american sound files

I noticed on the page that there was a strong NPOV bias against American 60hz power hum. The European file sounds slightly annoying but quiet and easily dismissed, whereas the American file is loud, obonoxious, and contains a lot of harmonics and distortion. Could this be some Wikipedian's plot against the United States' preferred power frequencies?

Alright, kidding aside, I am curious as to why the files sound so radically different. I would naively expect that the files would differ mostly in frequency, not in amplitude or harmonic power ratios... Is there something special about 60Hz or the American power system that promotes terrible sounding hum? If the American hum really is louder and more obnoxious, then perhaps these files are OK, however I can't help but feel like two very differing sampling methods were used in creating those files. That makes the comparison likely to cause others to (possibly) make bad inferences about the differing nature of electrical noises on different continents.

And yes, I'm aware that many places that use 50Hz are radically different (I'm sure Western Europe vs Africa is a nontrivial difference). Any answers folks? - JustinWick 17:21, 1 February 2007 (UTC)[reply]

They were recorded in different ways. There was a discussion somewhere, but I forget where. Maybe on the sound file talk pages. — Omegatron 17:37, 1 February 2007 (UTC)[reply]

Does Image:MainsBrum50Hz.ogg sound better? See Image talk:50Hz.ogg — Omegatron 17:42, 1 February 2007 (UTC)[reply]

Yes, much more fair and balanced. I think we should replace the one on the page with that one. Would you like to do the honors? :) - JustinWick 20:31, 2 February 2007 (UTC)[reply]

I can comment that my shitty mini-jack into my laptop soudcard makes the exact same 60Hz sound when I fidget with it, so I think it's pretty authentic.+mwtoews 08:56, 8 February 2007 (UTC)[reply]

MainsBrum50Hz sounds way more than the sound I'd expect. the one in the article sounds nothing like the noise I heard so often —Preceding unsigned comment added by 217.190.176.80 (talk) 23:29, 6 October 2007 (UTC)[reply]

Tone

The section on tone currently talks about 60 Hz and 50 Hz tones and the piano key frequencies around those. But since, as pointed out previously in the article, the hum is primarily the 2nd harmonic and not the fundamental is that particularly relevant? Should the bracketing notes quoted be "B♭2 (116.541) and B2 (123.471)" around 120 Hz and "G2 (97.9989) and G♯2 (103.826)" around 100 Hz? Waerloeg (talk) 09:27, 11 February 2012 (UTC)[reply]

Can we really hear electrical current? I don't think so!

Ears detect pressure waves - sound - not electrical current. So the opening definition of mains hum as "an audible oscillation of alternating current" is completely wrong. Try listening to a mains wire.

Mains hum is an audible oscillation of *something physical*, which is *caused by* an oscillation of electrical current. — Preceding unsigned comment added by 176.34.255.223 (talk) 16:17, 27 March 2013 (UTC)[reply]