Whatever is causing it has to be powerful enough to radiate. Remember the problem goes away when the microphone is moved away from the computer.
With Occam’s razor in mind: Poor shielding on a plastic microphone and radiation from a leaky computer seems to fill the bill pretty well.
Did you try the AM radio trick?
Koz
Ok so I tried that and it worked great, but as you said, not perfect. Sooo…
I have now worked with the best advice you’ve all given which is to eliminate the buzz in the first place. I’ve done that and am really pleased with the result. Now what I want to do is clean it up…just a little bit. I keep reading here that amateurs make the mistake of removing all the background sound, leaving a tinny and insipid end result. Which I completely understand. So how would I go about removing most of the hissing in this without just running it straight through noise removal (which would be my normal method)? I’ve read that I should not aim for ALL the noise to be removed but just to improve what I have. Which sounds great but - how do I go about that. I’ve attached a sample.
Thanks!
Paul
Right then. I got that clip to pass ACX Audiobook specifications. Attached.
Equalize to AM radio. (screechy sound)
LF_Rolloff for Speech (rumble filter)
Notch for the hum sound (120Hz)
Noise Reduction (hiss)
Normalize to pre-compress
Compressor to bring up overall volume
Normalize to meet ACX.
The recording was made in a room with echo from probably the walls. That’s the hollow sound. There’s no filter for that. You should record in a dead room with no echoes. I could probably get rid of more harshness with another filter, but I thought that was enough.
Koz
I can give you values for all of those steps and filters if you want. Remember you still have to clear the echo by yourself.
What’s supposed to happen is you record a passage, adjust the volumes a little and out the door. I got really close with a recording I did to make sure I could do it. There’s very simple filters and volume adjustment on this clip and it makes all three Audiobook standards. Attached. If I paid more attention to the room, I wouldn’t need one of the filters.
Koz
Thanks Koz. Yes if you can give me the values - is it fairly straightforward to apply? I just follow the steps above? Sorry I’m somewhat the novice here…
Appreciate your help on this.
Paul
I’m in Audacity 2.1.0 for these. That version has better tools.
is it fairly straightforward to apply?
No. We will be doing a lot of work and the final will sound more like AM radio than a high quality podcast. I know all microphones use the word “Studio” and “Professional” somewhere in the literature, but this isn’t one of those microphones. It’s hissy, screechy and it picks up noise from the environment. The notch filter is just to get rid of power hum in the show. Most microphones don’t do that.
Select the whole track by clicking just above the MUTE button.
– Effect > Equalization. Select Curve : AM Radio > OK That’s how I got rid of the high, sharp sounds in the performance. They can mess up the other tools. This is a good place to try custom equalization tools or even sibilance filters. That will prevent the muffled sound that I got.
– Effect > Equalization: LF_Rolloff for Speech. This one isn’t built-in. Steve wrote it and you have to install it into Audacity Equalization before you use it. I included it as an attachment. There should be a piece in the instructions how to install external filters.
http://manual.audacityteam.org/o/man/equalization.html
– Effect > Notch. 120Hz, Q 6. OK
– Effect > Noise Reduction. Drag-select a “clean” portion of the track. Something with no voice and no moving around. Effect > Noise Reduction: Profile.
Then select the whole clip by clicking above the MUTE button. Effect > Noise Removal: 12, 6, 6 (Top to bottom values), OK.
Effect > Normalize: Normalize to -3, Remove DC, OK
Effect > Compressor: -20dB, -50dB, 2:1, 0.2 sec, 1 sec (top to bottom). OK
Effect > Normalize: Normalize to -3, Remove DC, OK
That should give you a quiet track that passes ACX AudioBook specifications. We are doing a lot of surgery on the clip and it doesn’t sound very good compared to the original clip, but that’s what I got. ACX has been known to listen to work that only passes technical tests by the slimmest margin. Yours may then fail for voice quality.
Have you decided what to do about the room echo? That’s a physical problem. Hang moving blankets on the walls.
You should try to track down the source of the 120 Hz hum. (Reminder to Koz, Paul is in a country with 50Hz Mains). It might be a fan, the refrigerator in the next room or it might even be your computer.
The hiss is probably inherent in your microphone and/or microphone pre-amp. I went looking back through the thread, and I don’t think you ever told us what equipment you are using. If you are using the microphone preamp that is built into your computer with a computer style microphone then there may be room for lots of improvement with a relatively inexpensive USB audio interface and professional style microphone (probably a $200-400 investment).
By the way I was able to make Sample2 pass ACX with just the amplify to -3 and LF_Rolloff for Speech steps… but only barely. If you could get another 6-8 dB in the original recording by getting the microphone closer to your mouth or speaking louder you’d be there.
For what it’s worth I don’t hear any real problem with your room acoustics, I hear the hollowness that Koz mentions in his “patched” version but I think that is the effect of the “AM Radio” equalization as I don’t hear it in the original recording. (Or perhaps the noise in the original recording is masking the reverberation.) Either way the goal would be to get your noise level acceptable to ACX without drastic equalization or use of the “noise removal” tool (which IMHO usually just modulates the noise with your speech and makes it more apparent).
Hey guys
Thanks so much for all your time on this.
Flynwill, I use a very inexpensive mic, a Samson go-mic. Then it’s just plugged straight in to my desktop via a USB cable.
I don’t need my audio file to get past ACX filters, I just would like it to sound relatively good. I know that sounds strange but I’m not going to make a career of recording my books as audio books, but I have a little venture in mind that I’m working on, and for that I need to be able to prove that it’s easy to record an audio book without too much financial investment and without being an audio expert. (If it’s a successful venture then I will certainly be pointing my users in the direction of these forums!)
In the mean time, as soon as I get a quiet house, I’ll try the things you have suggested and hopefully I’m just about there!
Sorry for sounding a bit mysterious about my venture but hey, until it’s out there, I need to be!
I’ll let you know how I get on with the tweaking you’ve both helped me with.
Cheers,
Paul
I don’t need my audio file to get past ACX filters, I just would like it to sound relatively good. I know that sounds strange but I’m not going to make a career of recording my books as audio books, but I have a little venture in mind that I’m working on, and for that I need to be able to prove that it’s easy to record an audio book without too much financial investment and without being an audio expert.
I don’t need high quality, I just need high quality.
That’s what everybody on planet earth wants.
Turns out ACX has the series of tests that insure high quality. If you can’t make it past ACX, chances are your work has some serious shortcoming that will affect the product even for a casual listener.
“My voice is really quiet.”
'What’s that whine in my sound?"
“My voice sounds crashy and harsh.”
“I have this buzz that rides through everything.”
“My story has little clicks in it.”
“My voice sounds like I’m talking into a wine glass.”
“How do I get rid of breathing sounds and tongue clicks?”
“Why can’t I record over ten minutes?”
I didn’t even have to stop and think to make that list. I can make it longer if you want to wait…
This is what happens when someone plugs a cheap microphone into a cheap Windows laptop in a noisy, echo-filled room. Chances of success are, without exaggeration, zero. I don’t mean ACX success, I mean creating a sound file that anybody will want to listen to at all.
~~
Your startup needs to be a microphone that you wear close to your mouth that records your voice without the computer. The podcast is then created in Audacity (of course) by collecting all the sound files from the performers and mixing them into one show.
I got close to that by using stand-alone USB Stick Microphones, but they’re too noisy (fffffff).
http://www.tmart.com/8GB-UR-08-USB-Digital-Voice-Recorder-with-MP3-Function-Black_p126947.html
It was a close call though.
Koz
“I don’t need high quality, I just need high quality.”
Where did I say that?! Wow you are a harsh teacher Koz. Appreciate your help though, either way 
I’m curious can you put a number to “without too much financial investment”? (Without revealing your business plan).
For most folks the cost is only low because they already own the more expensive bits. Starting with a place to work (their house, condo, office etc). A computer to record to (which saves the expense of dedicated recording equipment). They might even already own suitable quality audio gear.
So for for the typical person (who already owns a suitable computer and place to live) its:
cost to refit a room, broom closet, or whatever to be both sufficiently quiet and sufficiently free of echos.
cost of an audio interface and microphones. (Loads of options, but I would budget minimum of $200, and $500 might be more realistic)
If they don’t own a computer then you have to add the cost of the computer, or a dedicated recorder of some sort.
Almost all the shortcomings of personal recording have to do with hardware, and by that I’m including your room. There is only one item in that list that has to do with an actual performance. All the rest are microphone, computer or room failure. People do manage to get good recordings with a particular combination, but it’s not universally applicable, and that will kill you on a startup or commercial product.
“I’m using the same microphone as you, but the sound is terrible.”
That’s the Yeti Dilemma. Everybody Knows you need to use a Yeti to get good recordings, and yet that microphone shows up constantly in postings from people for whom it failed. Is it a terrible microphone? No, not at all, but if your room and/or computer are terrible, that’s the end of the story.
There are two ways to get rid of room noise past soundproofing the room. Use a very directional (expensive) microphone or put the microphone very close.
There is one way to get rid of the computer and that’s to not use a computer. I did my last sound performance entirely on a Zoom H4 stand-alone recorder. No computer buzz, clicks, pops, delays, whine etc.
That’s a Zoom H2 sitting there on the rock.
https://www.youtube.com/watch?v=QcVec_RPwuc
Josh did the entire first couple of years of YouTube postings on that recorder.
The logical extension of all that is to use a small, stand-alone recorder next to your face and transfer the work to the computer later for editing.
If you do get something to work reliably for many people (that you’ve never met), do post back and tell us how you did it. Doing it for your friends doesn’t count. You are the sound engineer in that case.
Koz
The problem of the room can be solved with money of course… About $3,200 plus shipping will get you a complete turn-key recording booth.
Checkout http://www.whisperroom.com/sound-booth-standard-pricing.php
And yes, you can turn a broom closet into a recording booth. That’s what Ian did, currently the longest running thread on the forum. However, even though California is reputed to have no seasons, we do summer pretty well, and Ian has to come out of his sound-sealed closet every so often and gasp for air.
Koz
The turnkey booth includes an 80 cfm circulation fan (with suitable labyrinth passages to keep the sound out).
I only see one external vent. Do your ears pop from the pressure or vacuum? Does it reverse every so often? Not many options.
There was a one-port vent at a tiny gym I used to go to. It made satisfying noises and didn’t do much else. I used to prop the door open. I could hear the vent motor sighing, “Oh, thank you.”
Koz
Oh no, there’s both in and out. The standard unit has a fan that pulls air out from the top of the unit and another duct that lets air in at the bottom:
There’s also this testimony from a satisfied customer who replace where "modified broom closet with one:
http://www.lynda.com/articles/setting-up-recording-booth
The construction is basically an MDF box covered with thin industrial carpet of some sort. The “enhanced” units are box within a box. I suspect that if you were reasonably skilled with power tools you could fabricate a unit for yourself at a fraction of the cost.
There are tricks. The Jandy Studio which wasn’t soundproofed but had non-parallel walls. We sent a number of sound shoots through there.
Two thin WhisperRoom walls instead of one thick one. Done well with enough arithmetic, the chamber helps cancel the sound. Helmholtz? I can’t believe I remember that.
One of the items in the ACX documentation package does have me concerned. They have the noisy computer example outside the glass and the performer inside. That means a cable passage.
Koz
