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| rjisinspired |
| Posted: Feb 20 2014, 12:20 PM |
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Maybe someone else would have an idea about what would cause interference during a sound recording?
I have included a zip file with 4 examples of interference while recording with a Tascam DR07MKII. I have used Olympus recorders and I have never come across such interference nor cell phone interference. It has only happened with the Tascam device.
http://rjschat.dyndns.org:8080/Paranoha/AP...nterference.zip
The first two files (1 and 2) were recorded in my room. It seems like that type of interference has happened, so far, only in my room. I have no idea what is causing it. Doesn't matter if I use batteries or use the AC adapter that is for that model of Tascam recorder. Cell phones are off also when I do recordings with the Tascam.
The other files (3 and 4) is interference from a cemetery. I was doing an EVP session there. I am only curious what would cause that type of interference.
I am only concerned really with the first two files because they are from my room. I like doing vocal recordings in my room and I also do EVP there as well.
If anyone would know what would cause the interferences let me know. Thanks.
Oh yeah... if that link should go poop it means I got booted off the net. Ever since I went to dry loop service for DSL, the service went downhill. If the link ends up dead I will have it fixed asap. |
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| rjisinspired |
| Posted: Feb 20 2014, 12:29 PM |
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What the Tascam DR07MKII looks like:
Of course it is recommended to have a dead kitten on one of these:
The mics are extremely sensitive to any kind of slight wind. Even saying a word containing the letter "P" can blast the mics into oblivion if not careful. A mouse fart could probably do it also.  |
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| rjisinspired |
| Posted: Feb 20 2014, 12:58 PM |
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Sample of Cell phone interference:
http://rjschat.dyndns.org:8080/Paranoha/AP...Cellphone-1.mp3
No fun listening to something you recorded and you aren't looking at the wave graph then all of a sudden you get an earful of noise, lol. |
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| raffriff42 |
| Posted: Feb 20 2014, 02:22 PM |
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That's nasty. Are they that susceptible to interference?
Anyway, I tried importing into Audacity and using the Noise Removal Filter...
On interference-3.mp3, results seemed OK (some of the whine gets through, it's very piercing)
On interference-4.mp3, the interference is more severe; filtering out the noise makes the voice sound a little hollow, but usable.
How to use Audacity's Noise Removal Tool: - select a short segment with the noise alone.
- Effects, Noise Removal, click Get Noise Profile.
- select entire track (Ctrl+A)
- Effects, Noise Removal, Ok
- make sure Noise is set to 'remove' and not 'isolate'.
- normally, you use the using default settings ; but for interference-4, set sensitivity to +3.
- EDIT for "Noise Reduction (dB)," you want the maximum, 48 dB. You can even run the filter twice if the noise is still audible.
Here is a guide on voice processing with Audacity and VirtualDub.
This post has been edited by raffriff42 on Feb 21 2014, 12:56 PM |
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| raffriff42 |
| Posted: Feb 20 2014, 08:25 PM |
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By the way, what sample rate are you using? | QUOTE | Hissing Sound WHen Using Microphone [solved] (frapsforum.com)
You're not going to like this: I've seen several reports that going to 48000 or 44100 Hz fixes the hiss.
This article explains why: inaudible, supersonic noise in your computer [or microphone, or environment] is being made audible.
The Science of Sample Rates (When Higher Is Better — And When It Isn't) (trustmeimascientist.com)
Where More Isn’t Better: Rates Above 96kHz
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Yes, there is a point where you can have too high a data rate. Some would argue that point is closer to 96kHz, but almost any computer scientist or circuit designer today will tell you that you’ve definitely reached that point by 192 kHz.
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two super-sonic frequencies that cannot be heard, say 22 kHz and 32 kHz, can create an intermodulation distortion down in the audible range, in this case at the “difference frequency” of 10kHz.
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| rjisinspired |
| Posted: Feb 21 2014, 03:07 AM |
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Thanks raffriff.
That article was an eye opening read about higher sampling rates. Thanks for the links on that and for the use of using Audacity with Vdub. I think I will stick with Audacity for a little bit and test it out.
About the interference - It looks like these type of recorders are prone to noise.  Yet the smaller consumer recorders seem to not be bothered by them. I don't know why this is? I have had three Olympus digital recorders: VN240PC, DS30 and now a WS-802 and none of them picked up interference, not even cell phone interference.
With the Tascam I vary the sampling rate sometimes to see if there would be any difference with EVP work, for regular voice recording 44,100 should be enough. I record at 24 bits @ 96/44.1.
The Tascam DR07MKII has somewhat of a high noise floor but I guess for the price you get what you pay for but it is a little quieter than the Olympus recorders. |
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