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Subject:Phone hum
Posted by: timnc
Date:8/24/2004 7:18:43 PM
I sometimes do interviews over the phone, using one of those devices from Radio Shack that plugs into a wall jack at one end and into a recorder at the other. Works pretty well, but I get a low hum in the background. Does anyone have any ideas on how to a) eliminate this hum in the first place or b) eliminate it using Sound Forge 6? I've tried the Parametric EQ settings suggested in "Sound Forge 6 Power!"but to no avail. |
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Subject:RE: Phone hum
Reply by: RiRo
Date:8/24/2004 9:50:51 PM
First... get a real phone patch. The deal from radio shack has noise problems. I did radio news for decades... we recorded phones everywhere. The best is an aligator clip to line input... but finding a phone you can clip is tough these days. I have a Polycom phone that has record out... and it is surprisingly clean. Next... Noise Reduction 2 will pull tons of this kind of noise out. With EQ kill everything below 100 or 150... listen to the voice and see which sounds better... and kill everything above 4k to 6k, again listen to the voice and see which sounds better. Compress the voice a bit to tighten it up... works like a charm. RiRo |
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Subject:RE: Phone hum
Reply by: Rednroll
Date:8/25/2004 7:14:40 AM
Do these phone recorders record both sides of the conversation? I was thinking about building one of these myself, but has been on my tudo list forever. If the radio shack one records both sides I might pick one of these up and make a few modifications to improve the quality. This is for personal entertainment. I use to get really annoyed by telemarketers calling all the time. Now I just entertain myself with them. At one time in college I actually got a job as a telemarketer answering a help wanted ad. That lasted for one paycheck, and I said this is a B.S. job. So if anyone thinks I'm rough with some of my posts in these forums, you should hear me on the phone, digging into these telemarketers. I know the thing they like best, is if you're not interested is that you just hang up on them so they can quickly move onto the next call and increase their sales opportunities. So I usually keep them on the line for awhile and start criticizinng their technique and their bad choice of a career path. I've actually had one telemarketer break down and cry, and another tell me to F off. Oh. how I wish I had recorded those conversations. |
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Subject:RE: Phone hum
Reply by: rraud
Date:8/25/2004 9:42:25 AM
JK audio specializes in telephone audio interface. Check out the "Quicktap", about $60usd if your on a budget . http://www.jkaudio.com Forget Radio Crap |
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Subject:RE: Phone hum
Reply by: RiRo
Date:8/25/2004 10:08:00 AM
Yes, the RS dealy will record both sides of the conversation. If you must use it... record two channels... one with the record level set hot to get the caller, the other way less to get the person speaking on the local phone. The levels can be 30+ db different... so one level will not record all. There is lots of better equipment. The simple Aligator clips works very well... clip one to the red wire and one to the green... tip and ring... and you are good to go. RiRo |
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Subject:RE: Phone hum
Reply by: timnc
Date:8/25/2004 11:35:29 AM
Hi, RRio, Thanks for your post. Since I use a cordless phone and like to walk around the house during interviews, the alligator clip unfortunately isn't a good option for me. But the Noise Reduction 2 sounds great. Could you tell me what it is and where to get it? I'm assuming that the EQ setting you mention is something I'll do with NR2 once I get it. Is that correct? Thanks, timnc |
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Subject:RE: Phone hum
Reply by: timnc
Date:8/25/2004 11:39:06 AM
I'm recording to a Marantz PMD670 Digital Recorder. To record two channels, would I have to get some kind of splitter wire for the RS dealy that would plug into XLR adaptors for the right and left mic inputs? I guess I'd then have to check with Marantz as to how to get different levels on the two channels... Thanks, timnc |
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Subject:RE: Phone hum
Reply by: Rednroll
Date:8/25/2004 12:31:23 PM
"Since I use a cordless phone and like to walk around the house during interviews, the alligator clip unfortunately isn't a good option for me." It seems like the alligator clip should work with a cordless phone, even cordless phones are connected to the wall jack. That is unless the red and green wire you're talking about is the cord between the handset and the phone receiver. Which red and green wire are you referring too? Wall jack or Head set cord? |
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Subject:RE: Phone hum
Reply by: RiRo
Date:8/26/2004 10:15:41 AM
Red and green from the wall jack. RiRo |
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Subject:RE: Phone hum
Reply by: RiRo
Date:8/26/2004 10:18:46 AM
Personally, I wouldn't use a cordless. The phones we used had Push-To-Talk handsets to eleminate breath noise from the interviewer. Once you bring the level of the interview up, you will be so much louder than the other person, you will hear tons of room noise and breathing. NR2 is a sony product available through this site. The EQ settings would be done in soundForge's equalizer RiRo |
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Subject:RE: Phone hum
Reply by: mpd
Date:8/26/2004 1:33:45 PM
NR2 should be able to get a noise print and remove the hum, but it sounds like you don't have it. Try this. 1. Perform spectral analysis of the sound file. You should see a strong spectral line below 400 Hz or so. Figure out the exact frequency. 2. Configure parametric EQ to notch out that frequency. Play with the width. |
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Subject:Warning re phone lines
Reply by: farss
Date:8/27/2004 7:02:59 AM
Hopefully most here know this but just in case. Phone lines can carry 100s of volts, typically back EMF from all the inductance, to say nothing of 48V DC so you need to be careful playing with this stuff. I've had many decent belts of phone lines so if it can give you a decent shock it can fry your expensive audio gear big time. Also phone lines can have 100,000s of volts on them during storms so don't leave any kit connected permanantly. Use only approved gear or if rolling you own use transformers with 5KV isolation and high voltage capacitors and have surge supressors accross you side of the lines. Bob. |
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Subject:RE: Warning re phone lines
Reply by: Rednroll
Date:8/28/2004 4:40:05 PM
Good point Farss, I was going to mention this as far as the direct connection to the phone line. There is DC Voltage on those phone lines. When the phone rings there is a large DC voltage, put on those 2 lines. I think that's the largest around 110 Volts if my memory serves right. Then when you answer and hang up the phone there are 2 different DC voltages on those lines. You should be safe for some audio equipment if they it uses transformers or capacitors, but you're probably best to purchase a transformer so you can block the DC voltage and also impedance match better if connecting it to a mixer or line IN jack of your sound card. |
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Subject:RE: Warning re phone lines
Reply by: wethree
Date:8/31/2004 7:56:07 PM
hey all-- rraud-- I noticed at http://www.jkaudio.com that besides Quicktap there was another product called Celltap (for $79) that can tap a cell phone provide its user uses an earpiece or headset-- are there any special audio limitations to this kind of setup that lead it not to be grouped with all the other products lumped under TV/film applications (which Quicktap is a member of)? thanks for the info-- bestx3, bt |
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Subject:RE: Warning re phone lines
Reply by: rraud
Date:9/1/2004 12:12:23 PM
Wethree, If I understand your question correctly, the JK products are listed by catagory of probable industry user. The "Cell Tap", listed under "Radio" doesn't mean you can't use it for TV sound or feed to your computer sound card.. If used for it's intended purpose, the only limitation I see is the quality of your cell phone, cell phone service, connection, and headset. Naturally it won't have the quality and options of a $1000 phone interface. The output is unbalanced line level @ -16dB via a mono 1/8" mini jack so you may have to make or get an adaptor to feed the 1/8" stereo mini jack on most sound cards. |