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Subject:How to Record Phone Call
Posted by: Slammer
Date:8/3/2003 4:19:24 PM
I currently have voice mail that I would like to permanently save. (For example, my nephew singing happy birthday to me from 4 years ago.) I'm going to cancel my phone number, so I need to save these somehow. Is there a way I can use my modem, windows 2000, and sound forge 6.0 to record something from a phone line? Any help/advice would be a huge help. Thank you in advance! |
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Subject:RE: How to Record Phone Call
Reply by: Chienworks
Date:8/3/2003 5:27:05 PM
If you have a voice modem then it should have come with some sort of answering machine / call recording software. Search through the manual or help screens that came with it. It might possibly be called a MEMO function. The easiest idea, and one that i've used many times, is to simply put a good mic up against the earphone of the telephone and record that way. It helps to have the room very quiet. You can correct EQ after recording it to help it sound more natural. Another option is to buy or build a recording interface for the phone line. Radio Shack sells one for a few bucks that plugs in between the phone and the line jack and has a 1/8" mini plug to connect to a mic in jack on a tape recorder. This should connect to your sound card as well. I've built one that uses a small audio transformer across the phone line and delivers a line level signal to the sound card. A word of warning though ... if you try building something like this do not connect it to the phone line until AFTER you've made the phone connection (dialed or answered). The voltages that come down the line while the phone is ringing could easily burn out whatever device you connect to the transformer. |
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Subject:RE: How to Record Phone Call
Reply by: Rednroll
Date:8/4/2003 8:41:47 AM
Chienworks, This is some great information. Just wanted to comment on your design. Yes, when the phone rings it is a higher voltage, than the rest of the signals. 58-64volts DC, if my memory serves me right. But if you put a transformer in your circuit as the first stage, the phone line is connected too, then anything on the other side of the transformer should be blocked since a transformer eccentially blocks DC. If you're having problems, you might need a bigger transformer. The other thing you might want to consider adding to your design, if you're worried about detroying your sound card is a zenor diode. This will act as a voltage regulator. Red |
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Subject:RE: How to Record Phone Call
Reply by: Chienworks
Date:8/4/2003 11:21:06 AM
Red, good idea on the Zener diode; i hadn't thought of that. Actually, transformers don't so much block DC as they only transmit varying voltages. The ring signal isn't constant, it keeps switching on and off. Each time it changes there will be a surge transmitted through the transformer. Standard ring signals are supposed to be 20Hz sine waves (so as to interfere as little as possible with neighboring signals). This would be transmitted through the transformer to some degree. |
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Subject:RE: How to Record Phone Call
Reply by: mcgeedo
Date:8/4/2003 2:37:36 PM
Hey Red, I can tell from some of your previous posts that are pretty technically savvy. I'd like to bounce an idea off of you, if I may. The BOSS wants his conference room to have much better telephone conference audio than it currently has. We're currently using a PolyCom analog unit with two extension microphones on a 25-foot table. His complaint is that he has to move the mics around so the other party can hear. I'm thinking a couple of electret "chorus" mics hanging from the ceiling, into a mixer, into a two-channel compressor (like maybe a Behringer MDX2200), into a line interface (like a radio-talk-show hybrid). Set the limiter to the max line level and set the compressor to just under the point where the room starts "breathing," if you know what I mean. Would you please comment? Also, any web pages where one might go for this sort of info. I've done a bit of pro audio (which is why I have this silly assignment), but I haven't done much phone work at all. Thanks in advance, -Don |
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Subject:RE: How to Record Phone Call
Reply by: Rednroll
Date:8/4/2003 6:32:53 PM
Ahhhh....yes I'm going through my old college senior project notes now. I found the ring signal was actually a 150V AC signal. When the phone was OFF HOOK, it was 9 Volts DC and ON hook, the phone line was 52Volts DC. My senior project was a device, that would detect the phone ring....it had a microphone on it, and it monitored the audio level within my living room. If the audio was too loud, it would spit out the infared codes to turn the volume down of my home entertainment system, to a lower level so you could hear the phone ring and talk. It then detected, when you would pick up the phone and hang it back up. Once you hung it back up, it returned the volume to where it originally was. Perfect for a college bachelor pad, where we where always jamming the stereo, and we where always running to turn down the volume down and couldn't find the remote buried under all the beer cans, only to answer the phone, to find out it was some friggin telemarketer. You need a high pass-filter. Simple Resistor and capacitor should do the trick. |
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Subject:RE: How to Record Phone Call
Reply by: Rednroll
Date:8/4/2003 6:45:38 PM
"I'm thinking a couple of electret "chorus" mics hanging from the ceiling, into a mixer, into a two-channel compressor (like maybe a Behringer MDX2200), into a line interface (like a radio-talk-show hybrid). Set the limiter to the max line level and set the compressor to just under the point where the room starts "breathing," if you know what I mean. " We just happen to have one of the polycom video conference devices, setup in a conference room, so I have an idea of what you're referring too. I'm not totally familiar with the inner workings of this thing, but the few times I've been on a teleconference, I could hear the "gating" going on, when people where talking. Most telephone conference systems have a noise gate on them to keep the room noise down, that the mic picks up when you're not talking. The problem I foresee with your solution, is that you will bring the level of the room noise up too far, therefore the gate will always be open. Therefore, the party on the other end will be highly irritated listening to the lights buzz and natural reverb of the room all the time. Unfortunately the only real solution to this problem is for everyone to have a head-set microphone, and run that into a mixer, then into the polycom. That way you could keep the microphone gains low, to avoid too much background noise, yet the gate would open when that particular person spoke and since they're close miced, it would be a more direct sound. |
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Subject:RE: How to Record Phone Call
Reply by: keether
Date:8/4/2003 7:00:35 PM
Slammer actually needs to record messages which he already has---and has had for some time (4 years). He has voice mail messages and wants to preserve them. He's not going to build any mechanism for this phone because, as he says, he's cancelling the service soon. If it were my problem, I'd play the messages back into a microphone attached to a tape-recorder. Then I'd digitize the sounds via the line-in. Slammer, is the recording device you have digital? That might make a difference. |
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Subject:RE: How to Record Phone Call
Reply by: Rednroll
Date:8/5/2003 8:18:26 AM
"If it were my problem, I'd play the messages back into a microphone attached to a tape-recorder. Then I'd digitize the sounds via the line-in." yeah, good suggestion.....sounds exactly like Chienworks second suggestion, but his is better because he didn't recommend a "tape recorder. " or suggest 2 recording steps to get there. "Slammer, is the recording device you have digital? That might make a difference." ahhhhh yeah.....it's called Sound Forge. Is this thing on? |
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Subject:RE: How to Record Phone Call
Reply by: captn_spalding
Date:8/5/2003 9:45:12 AM
Slammer,Take a look at Radio Shack Catalog #: 44-533. It's about $5.00. I used one of these decades ago and I think it will work fine for what your trying to do. ..spalding |