Please help - To Choose Clean Audio (Loud Humming noise Comes from outside)

Discussion in 'General Discussion' started by CatMalone, Jun 5, 2019.

  1. CatMalone

    CatMalone Active Member

    Joined:
    Jun 5, 2019
    Location:
    United States
    Hello,

    I've a a home studio and invested in good gears. Fortunately all was going well but ever since summers started, I've been facing an issue:

    Someone runs an old era machine day and night, near my home and it makes "a lot of annoying humming noise which comes in my room and my floor also vibrates" Even at night I can't record (it's 3:59 AM right now). Also sound acoustic panels doesn't work at my place and also they cost fortune here :) so

    I fine tuned a lot of other things :
    I tried to remove the background humming noise using 3 different software's / techniques:
    1. Audacity
    2. Adobe Audition CC 2019
    3. OBS studio (used plugin)

    and recorded a video.

    Unfortunately I don't have studio monitors nor monitor headsets so when I listen to the post processing in my multimedia headset they all sound differently.

    I request you if you have studio monitors nor monitor headsets, please watch my video where I shared 3 different test clips

    https://www.dropbox.com/s/3zakvjac930exs4/_Noise_removal-for-forum.mp4?dl=0

    and please let me know out of these 3 clips which sound better (or professional)

    Trust me it would be a great help :) and I'm grateful to you.
     
  2. paulears

    paulears Well-Known Member

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    Well I'm completely confused - the video is nearly 4 :30 long and I didn't;t hear any hum? I heard test one which was at least constant level. it sounds like it's recorded In a very hard walled room - not pleasant to listen to. Recording 2 seems to have been gated in some way, and the third one chops in and out. What we needed is the raw audio WITH THE HUM - so we can hear what it sounds like before you try to cure it. We have no idea what the problem sounds like. It just sounds very hard and has short term reflections and is difficult to listen to. If you want to record voice, it seriously needs treatment - absorption in the main.
     
  3. CatMalone

    CatMalone Active Member

    Joined:
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    I'm grateful to you for sharing invaluable feedback and I acted upon what you suggested :) so here is my reply with a Raw audio which has Humming noise:


    Yes your guess is correct I recorded in a room which has walls made up of concrete but this is where my home studio is and at present this the only option I have.

    I'm afraid, I didn't understand this "it seriously needs treatment - absorption in the main" It will be great if you explain a bit, as I'm new to recording world.



    This is Raw Audio file with humming Noise (this time I made the audio file Very Short so that it doesn't take much time):

    1. The first 30 seconds is just a humming noise and then I started speaking and at the background still humming noise is coming :
    https://www.dropbox.com/s/c3m1s8iv9iam4n0/_Raw_Audio.mp4?dl=0

    2. Here is the cleaned audio file (initially I showed, how did I clean it in audacity - first 30 seconds and then my voice starts)
    https://www.dropbox.com/s/2egitvgfzbweodr/_Clean_audio.mp4?dl=0

    Please share your invaluable feedback :)
     
  4. cyrano

    cyrano Active Member

    Joined:
    Feb 4, 2018
    Location:
    Brussels
    As I suspected, the hum is in your playback system, not your recording. There is a bit of noise (hiss), but nothing to worry about.

    Also, your recording level is fairly low.

    Don't shoot me if I missed anything, was listening back on laptop speakers. I'll have a second go tomorrow on some real speakers :D
     
  5. paulears

    paulears Well-Known Member

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    Lowestoft - UK
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    I took the video file, extracted the audio, normalised the background and the background/voice mix.

    The result is quite clear. Wideband noise, probably from an aircon HVAC unit, or maybe air handling ducting. My last fix would be using processing. As you've discovered when you try to remove wide band noise, especially low frequency heavy, like this - the process leaves artefacts that make the sound grim. So for me, I would be looking at the room. You need treatment - the first treatment is to identify where the noise is coming from, and sometimes your microphone and a pair of headphones can help you find where it's coming from. Windows, doors, ventilation ducts - these can all be solved quite cheaply. If the noise is coming from a duct, it's caused by air movement, so you can try a few things. Simplest of course is to block it off with something temporarily, but you can sometimes build devices that are bigger than the duct, then line the inside with foam or wall insulation, but the low frequencies that are predominant mean the box may have to be quite big too be effective. Doors can be beefed up with extra layers, and windows can be double glazed. The other solution is simply to stop the noise getting to the microphone. a normal boom mic stand, pulled fully up, and then with the boom horizontal can be used to hang a duvet that becomes a barrier between the mic and the noise. your concrete room is reverberant, but because the size is small, the reflections are quite short and flutter, probably due to walls being parallel. Another couple of duvets can make the room sound much, much better. Cyrano mentioned the levels - you are recording quite low, so we need to apply gain to listen and this increases the background electronic noise.

    So -
    Identify where the noise enters the room. put barriers in place that will reduce it.
    Increase signal to noise. Decrease the distance from you to the mic, and increase the distance of the mic from the noise.
    Change the position in the room you place the mic to one less noisy.
    Treat the room with things that absorb - if you cannot afford commercial products to do this, soft furnishings work pretty well but look silly!

    It's NOT a hum, by the way - hums tend to be very small bands low in frequency - yours is just low frequency noise.
     
  6. CatMalone

    CatMalone Active Member

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    Location:
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    Thank you, as I mentioned in my initial post, the noise is coming from outside of my home, as there is big machine running there day and night, it has a big old era fan which makes this noise, my floor vibrates and that old fan makes Broom droom noise, may be that's the reason you suspected it's fan/Air conditioner noise...

    Let me explain, earlier I reduced the gain (in audio interface so that mic picks up less noise) that's why It sounded like Air Conditioning noise whereas it was not, this noise is coming from outside.

    1. Yes I can hear the noise with my ears, all the time (at least at night noise sounds too loud because it's all quiet all around)

    2. It's not computer fan or vent or Air conditioner, trust me. Neither I run fan nor Air conditioner while recording even it's 48 degree temperature here. All this noise comes from outside. BTW as I already mentioned Acoustic panel doesn't work here and also that cost here a fortune.

    So now I increased the gain and noise is more clear .

    I tried low pass filter in my mic but that didn't do well.

    Based on your suggestions:

    Note: So now I adapted a different approach:

    1. I changed my sitting position
    2. Now mic is too close to my mouth
    3. Gain level is increased

    4. I also make sure fan, air conditioning etc.. not even run in adjacent rooms (in fact in my room I already don't run em while recording).

    5. Most importantly now I recorded the noise for 30 secs (I don't know what to call it may be it's not hum but surely it's kind of noise) and afterwards I started speaking something. Now I'm providing you "Audacity Project files" and also "Raw Audio", and the "clean audio which I cleaned via audacity" so that you can analyze:

    https://www.dropbox.com/s/9ax0omd1mf2xjer/_Raw_audio--and--Audacity_project.zip?dl=0

    I believe if we come to know what kind of noise it is then you may suggest me a specific way to cure this audio.

    I'm so much grateful to you for your priceless efforts, I really wish to fix this issue so that I start doing my work, thank you guys, you are Great, Genius

     
  7. paulears

    paulears Well-Known Member

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    Why do you think it is too close? No popping or wind noise. Maybe even closer, with a pop shield and perhaps some eq to remove the extra bass you will get.

    My take is this. if you cannot prevent the sound getting in for practical or budgetary reasons, then live with it. all the noise reduction treatments are going to make your voice quality worse. I'd put up with the noise and benefit from the tonal quality of your voice, than have the strange phasey sound the treatment always gives.

    What are you recording? Spoken word, I assume and not music. Sometimes recording spaces are just compromised. I rarely record spoken word, usually music, but my aircon, even in the UK fails to be that good in the summer, and I've often recorded with the doors all open to create some air movement. in the background of a sax solo, you might find a distant dog bark, or police siren. in the mix, it's invisible.

    I really do not think noise reduction will help with this low frequency Wideband noise.
     
  8. pcrecord

    pcrecord Quality recording seeker ! Distinguished Member

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    Healty voice recording distance from the mic can be as close as touching lips with a dynamic mic and 2-3inches with a condenser mic with a pop shield.
    The closest you get, will allow to record at lower gain settings and so less noise will be grabbed.

    What is the mic and audio interface ?
     
  9. CatMalone

    CatMalone Active Member

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    Thank you, you must be expert because so far all your guesses are correct by just listening from my audio files:

    1. I use good quality pop filter

    >What are you recording? Spoken word, I assume and not music
    2. I'm recording education video course, yeah it's all spoken word. I teach through video lessons as doing it professionally so audio quality must be food that's why putting all efforts.

    I'm grateful to you :)

    3. I use this:
    Mic: MXL 770 with shock mount + Pop filter double layer

    Audio Interface: Focusrite Scarlett solo 2nd gen

    DAW: Audacity for voice recording, I also invested in Adobe Audition CC 2019 but that doesn't remove noise very well like Audacity, may be I need to learn Audition better

    Rest all other gears and equipment are also good and chosen carefully after doing a lot of research for my home studio.

    Q) As I use ML 770 condenser mic do you think is I should switch to dynamic mic, will I get any benefit because they tend to pick less background noise? What do you think?



     
  10. CatMalone

    CatMalone Active Member

    Joined:
    Jun 5, 2019
    Location:
    United States
    Thanks for replying.


    >What is the mic and audio interface ?
    3. I use this:

    Mic: MXL 770 with shock mount + Pop filter double layer

    Audio Interface: Focusrite Scarlett solo 2nd gen

    DAW: Audacity for voice recording, I also invested in Adobe Audition CC 2019 but that doesn't remove noise very well like Audacity, may be I need to learn Audition better.
    Rest all other gears and equipment's are also good and chosen carefully after doing a lot of research for my home studio.

    Q) As I use ML 770 condenser mic do you think is I switch to dynamic mic, will I get any benefit because they tend to pick less background noise? But someone told me that dynamic mics (almost all) like SM58 etc... need more pre-amp so you also need to invest in a good dynamic mic + in a Cloudlifter Mic Activator (which will give extra 25% clean pre-amp to mic). Is that correct?

    I'd love to see your reply.
     
  11. pcrecord

    pcrecord Quality recording seeker ! Distinguished Member

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    Condenser mics tend to grab more of the surrounding noises and reflection of the room but they usually have a higher output level.
    Dynamic mics will capture less of the surrounding but need more gain on the preamp side. The Scarlett solo would be on it's clean limit to drive a sm57 or similar mic but if you don't have any treatment in your room. It could be a good way to get cleaner recordings.

    The MXL 770 isn't the cleanest mic around. At some levels, it may produce electronic noise by itself.
    I suggest you try to place it at about 3 to 6 inches from the source and set the gains so your recording levels register around -18db to -10db in your DAW.
    Also, louder sources need less gain therefor will produce less noises.
     
  12. paulears

    paulears Well-Known Member

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    You know - with a proper pop shield, you can get surprisingly close. Just recently I've had to record some voiceovers for a track where for various reasons, I could not use headphones, so the mic would pick up the sounds coming from the speakers. This is a similar problem to the one you have. I can put the pop filter 'disc' almost touching my AKG 414 I'm using then put my lips almost on the mesh, and it's pop free and the unwanted sound way down.

    I really believe your problem is simply setup.

    In your position why not see if you can absorb some of the unwanted sound by barriers. Have you seen those semi-circular shields that cover the rear of the mics, they're pretty good at speech frequencies and will help for sound coming from behind the mic. You can buy the branded ones for lots of dosh, but there are cheaper import ones, and of course as they're mainly foam and rock wool type materials, maybe you could just try making something.

    I really t think you need to scrap the electronic obsession with removing noise - on spoken word it's just not viable as you can hear the noise reduction doing it's thing. It's fine when the treated source is just one in a mix. You could make up some panels- maybe 600-700mm square that will sit on a desk, and have two sides, a back and a top, and then add the absorption inside, and then draw your chair up and put the mic in the box, and perhaps a bit of you too - I bet this sounds a lot better. Simply forget electronic treatment, but slice off the bottom of the mic so below 150Hz or so, the response is down. It doesn't have too much impact on your voice and will remove lots of the low rumble. If you can find the right position, then it's repeatable, and simple. Don't use any compression, limiting or dynamic processing until you get a sound you like, then try some gentle - repeat gentle tweaking. putting the mic in a enclosure can be a revelation.
     
    pcrecord likes this.

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