DaikenTana Posted August 6, 2005 Report Share Posted August 6, 2005 (edited) Hi allDoes anyone know how to prevent this? My guess is to buy a battery box to give the mics their own power, but would that work? This only occurs when next to electronic devices (TV, computer, microwave) Edited August 6, 2005 by DaikenTana Quote Link to comment Share on other sites More sharing options...
MZ-NH1 Posted August 6, 2005 Report Share Posted August 6, 2005 (edited) Maybe it is just the different eletrical waves all too close to each other. As you said - you are near computers, microwaves... I don't know if those devices should effect your recording.. but they might be.Try recording something away from those devices and see what happens?Someone should be able to give you a better explanation then me though... so just wait a bit until someone else replies Edited August 6, 2005 by MZ-NH1 Quote Link to comment Share on other sites More sharing options...
A440 Posted August 6, 2005 Report Share Posted August 6, 2005 If you are recording while using AC power, it has been reported that you can get a hum. Try recording on battery power instead. And yes, keep it away from the other gizmos if possible. Quote Link to comment Share on other sites More sharing options...
greenmachine Posted August 6, 2005 Report Share Posted August 6, 2005 Although supplying the microphones with a higher bias voltage is generally a good idea, a battery box wouldn't help with this particular problem at all, it could make it even worse because you're extending the cable. A microphone cable behaves much like an antenna, particularly if it's unsufficiently screened. The longer the cable, the worse the screening and the closer to an electromagnetic field, the more low frewuency buzz you'll get. The task of the condenser used in battery boxes is to prevent dc voltage to pass from/to the recorder. If an electromagnetic field is picked up through the microphone cable, it would pass through the battery box easily since it's an ac voltage. Quote Link to comment Share on other sites More sharing options...
The Low Volta Posted August 6, 2005 Report Share Posted August 6, 2005 I recorded a test with batt box->mic in and ac-adapter plugged in standing amidst a bunch of PC's (3 laptops), tv-cable, a TV, two wall sockets and a lot of electric cabling... the low hum was more like a huge buzzz... I could hardly hear what I actually recorded (to show how daft I actually can be... no this wasn't a test for the above... I just couldn't wait till my NH900 was charged to run the first test of the mics and batt-box I got from greenmachine (big thank you again g!!)... and that socket was the only one available at the time Luckily I immediately realized that it was my own mistake and the circumstances ruined the recording, not the mics ) Quote Link to comment Share on other sites More sharing options...
greenmachine Posted August 6, 2005 Report Share Posted August 6, 2005 Although they vary in quality, there's propably no perfectly screened microphone - cable - whatever additional equipment - cable - recorder chain, it's always advisible to keep a healthy distance to potential electromagnetic fields. In a test, the docking station of a cellular phone showed fatal influences. If you want to get seriously radiated, just stay all day long next to such a thing, it's propably not much different from heating yourself in a microwave oven at lowest setting. Quote Link to comment Share on other sites More sharing options...
jdisdle Posted August 6, 2005 Report Share Posted August 6, 2005 TV`s PC`s, Microwaves and all electrical equipment can emit interference when working. Hum can be picked up from mains cables if you are close enough.A mic. in a plastic case, plugged into a Minidisk also with a plastic case is not a good idea in this situation. A metal bodied mic. with proper screening would help.John. Quote Link to comment Share on other sites More sharing options...
DaikenTana Posted August 7, 2005 Author Report Share Posted August 7, 2005 Aah, thanks. So the only solution in my case is to either turn off all electronic devices or just not record near them at all.It's funny though, I don't get this buzzing noise when I have the MD in my hands and the mics are in my ears. Quote Link to comment Share on other sites More sharing options...
jdisdle Posted August 7, 2005 Report Share Posted August 7, 2005 You say the buzz occurs when next to these devices. How near is next? Is pick up from the mic. or the minidisk itself?PC`s and Microwaves have fans. Fans are noisy. Is this what you are hearing rather than mains hum?You would have to be within a foot of the TV to pick up buzz. What's so special about recording next to these infernal devices??? Quote Link to comment Share on other sites More sharing options...
raintheory Posted August 7, 2005 Report Share Posted August 7, 2005 I've had the buzzing using AC power on a few occasions.. Odd though because it seems to be only certain outlets.I did notice however, just as daiken said, that the hum/buzz was considerably decreased if I was touching the unit. Quote Link to comment Share on other sites More sharing options...
DaikenTana Posted August 8, 2005 Author Report Share Posted August 8, 2005 (edited) Yeah, what the hell's up with that.I held the mics really close to a power plug and the buzz practically overloaded the preamp!I've tried attaching the Clamp filters to different cables but they don't do a damn thing. Edited August 8, 2005 by DaikenTana Quote Link to comment Share on other sites More sharing options...
The Low Volta Posted August 8, 2005 Report Share Posted August 8, 2005 wouldn't you yourself be grounding the machine when holding it with your bare hands? so the buzz diminishes... bad grounding perhaps also explains why the ac-adapter causes this much hum and why certain sockets do even worse than others? just my thoughts though... Quote Link to comment Share on other sites More sharing options...
md-max Posted August 8, 2005 Report Share Posted August 8, 2005 I've got that same hum problem. For 'normal' MD recording yes you can do it off battery power but with the 1Gb discs, you need to be running off the mains adapter. And that of course has a plastic earth pin. So how else could you earth it? And what to? I assume a bit of wire stuck into the earth hole of the socket in the wall would not be the most sensible idea.And it sounds like I need some shorter stereo cables for recording from the radio...Anyone else have any advice? Is there such a thing as a screened cable with a stereo plug at each end? Or isn't that going to help?wouldn't you yourself be grounding the machine when holding it with your bare hands? so the buzz diminishes... bad grounding perhaps also explains why the ac-adapter causes this much hum and why certain sockets do even worse than others? just my thoughts though...← Quote Link to comment Share on other sites More sharing options...
The Low Volta Posted August 8, 2005 Report Share Posted August 8, 2005 For 'normal' MD recording yes you can do it off battery power but with the 1Gb discs, you need to be running off the mains adapter.what HiMD model are you using? with my NH900 and a 1350mAh gumstick and an alkaline AA in the addon I recorded for 7 hours (in HiSP on a 1gb disc), played songs for another 6 hours (from other 1gb discs) and still had some juice left...so unless you really need to record for 15 hours straight in HiLP or something, why wouldn't you be able to record from battery power? I won't record with the AC-adapter again if I can avoid it, as the buzz really was annoying and overwhelmingly loud...so I always carry a spare (fully charged) gumstick and a fresh AA for the addon... Quote Link to comment Share on other sites More sharing options...
greenmachine Posted August 8, 2005 Report Share Posted August 8, 2005 Now that we are talking about hum from the power supply, i did a quick test:With the supplied switching power adaptor, there is a huge amount of hum/noise regardless if recording from line-in or mic-in. Grounding doesn't help at all. The supplied adaptor seems to be not suited when recording from an analog source.With a universal regulated transformer power adaptor (non-switching) there's way less hum when recording from mic-in, virtually insignificant if recording from line-in. When grounding it (outer ring of the power / headphone / mic-/line-in connector), you'll get rid of the hum completely. Quote Link to comment Share on other sites More sharing options...
md-max Posted August 8, 2005 Report Share Posted August 8, 2005 Good point. I'd forgotten that the 1350mAh gumsticks were so much better than the crummy one supplied with my NH900 and therefore would be good enough (just bought two of 'em last week). D'oh!(Do you still need the AA to record the full 7 hours of Hi-SP on a 1Gb disc?)what HiMD model are you using? with my NH900 and a 1350mAh gumstick and an alkaline AA in the addon I recorded for 7 hours (in HiSP on a 1gb disc), played songs for another 6 hours (from other 1gb discs) and still had some juice left...so unless you really need to record for 15 hours straight in HiLP or something, why wouldn't you be able to record from battery power? I won't record with the AC-adapter again if I can avoid it, as the buzz really was annoying and overwhelmingly loud...so I always carry a spare (fully charged) gumstick and a fresh AA for the addon...← Quote Link to comment Share on other sites More sharing options...
The Low Volta Posted August 8, 2005 Report Share Posted August 8, 2005 Do you still need the AA to record the full 7 hours of Hi-SP on a 1Gb disc?I must admit that I've never tried that... I always use the addon, as I would dread to lose a recording due to low battery power and I think the addon isn't too irritating to usebut if you'd like to know, just try it (set it to record and let it run till it stops, could be a great test to see if the machine saves on time as well)...and let us know the results Quote Link to comment Share on other sites More sharing options...
greenmachine Posted August 8, 2005 Report Share Posted August 8, 2005 I get about 16 hours with a 2300 mAh battery in Hi-SP mode, with 1350 mAh it should be at least 7 hours, more like 9+ hours if it is in good condition. It will usually save the system file automatically before shut-off if the battery is in good condition, but i wouldn't rely on it. Quote Link to comment Share on other sites More sharing options...
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