Using a Mixer w/Audacity to do Interviews on a Landline.
November 26, 2012 5:55 PM   Subscribe

Using a Mixer w/Audacity to do Interviews on a Landline.?

I am using Audacity v2.02. I am also using Windows XP x32 but I may be upgrading to Windows 7 x64. I want to conduct interviews via a landline using an Alesis MultiMix4 w/USB connector. My PC is connected to the landline through an Intel (R) 536 EP modem v.4.76.70.
- In Audacity there was a phone line selection in the input dropdown menu which I selected. But I didn't hear a dial tone when I clicked record.
- In Control Panel > Audio Devices and Properties > Audio tab, there is a selection for modem #0 record and modem #0 playback. I selected these. The same selections are in Audacity in the input and output dropdown menus. I selected them too. But this configuration gave me an error that said I needed to check the input source and the sampling rate. The sampling rate for a landline is 8Khz. I changed the sampling rate but kept getting the error.
- The Audio tab in Audio Devices and Properties also has a USB Audio CODEC option which I selected thinking it would be a better connection to the mixer. And yes, it does let me record to Audacity through the mixer when the microphone input is selected, but there still seems to be no connection between Audacity and the landline. I thought that through the USB, I could not only talk to who is on the phone through a microphone which is connected to the mixer, but listen to them through the mixer too.
Can the hivemind give me any help? Thanks.
posted by CollectiveMind to Computers & Internet (6 answers total) 2 users marked this as a favorite
You're overthinking this unless you need a superduperhighquality recording. One mic on you, one mic on the phone on speakerphone. Speak clearly. It sounds fine, not NPR grade, but pretty good.
posted by Potomac Avenue at 6:21 PM on November 26, 2012 [1 favorite]

You can also use an earbud mic, like this one, and use a 1/4" adapter to put it through the preamp (though of course you could also just use the line-in jack). I also think the modum part's maybe a bit complicated.
posted by nelljie at 7:38 PM on November 26, 2012

Hmmmm . . . . . .

Well, Potomac Avenue's idea is worth a shot, simply on the KISS principle.

Mostly I think your problem is the very nature of telephones & how they carry signal. I've only ever gotten phones to interface with audio systems by using what's usually called a "phone hybrid coupler."

There's something about how the phone has internal circuitry that isolates the speaker and the microphone in the handset from each other, and that allows the phone company's switchers to know when the phone is on the hook, and when it's been answered, and to send voltage down the line to trigger the ringer, and some other interfacing between the switchers & the phone line that requires an external piece of equipment in order to get audio in & out of a phone line.

I found this article (pdf link, Recording Interviews), and more info here: Telephone Interface

In short, I think you need an actual telephone connected to a phone line, I don't think a modem will do it.

Then the question is how to get audio out of the phone. This page from the Audacity forum seems to have some good info - check out page 2 for a layman's quickie explanation of how phones carry audio. One person suggests a cheap piece of gear from Radio Shack (Mini Recorder Control) and there's some discussion about how to use Audacity to compensate for volume differences.

For a bit more money you could get the JK Audio QuickTap.

Either way, you can skip your Alesis mixer (phone lines are really limited in frequency range, running it through the mixer probably won't make any difference), hook one of these or a similar device between your phone & the mic/line input on your computer, conduct the interview over the telephone & record it in Audacity, then use the various options available in Audacity to clean up the recording.

(As a bit of a side note, Audacity is a really great program for a freebie, but I've definitely had issues in the past trying to use "non-standard" input & output routing. Sometimes I've only succeeded through trial and error, including changing settings in the program or in the audio control on the laptop, then restarting the program or rebooting the whole computer. This is obviously not ideal for you.)
posted by soundguy99 at 8:03 PM on November 26, 2012 [3 favorites]

2nding Soundguy's take on this. I don't think you'll get the modem to transmit/receive anything but data.
posted by drhydro at 10:49 PM on November 26, 2012

Just to elaborate on the previous answers:
Both the JK QuickTap and the Radio Shack Mini Recorder Control are connected between a phone and the handset.

The Quicktap then connects to the microphone input of your computer/USB audio interface. If you record from this input you will get a single channel with both transmit (your voice) and receive (the person you're interviewing) audio mixed. I think it will vary from phone to phone if your voice and the voice of the callee will be equally loud in the recording (playing with your phones volume control might help). You conduct your interview by using the phone as you normally would.

The Mini Recorder Control is connected in the same way and with the switch in the record position it will most probably work just like the Quicktap. With the switch in the play position you can inject audio into the phone which will be heard by the callee.

I think it's possible to use your modem to accomplish something similar - based on my experience with modems like these (and reading the abbreviated datasheet) - but this may get complicated and could take a while to get working. If you're lucky you already have a telephone application installed that came with your modem. It would also help if you could find the manufacturer information of your modem. Intel 536 is just the name of one of the chips on your modem.
Regarding the Audacity error: Have you tried changing the default sample rate in Edit -> Preferences -> Quality to 8000? Just like soundguy99 I'm a bit unsure how Audacity handles these things - if they take effect immediately or a application restart is needed.
posted by mirage pine at 2:23 AM on November 27, 2012 [1 favorite]

More thoughts, now that I'm freshly caffienated and on an XP computer:

1) It's a little tough to do detailed troubleshooting, because a lot depends on the capabilities of your particular computer's hardware, like the sound card or the modem. I have no modem option in my Audio Devices control panel, although it's possible one might show up if I was connected to an external modem.

2) There's something kind of circular about your signal flow, and it seems like you're trying to use Audacity as both a signal router/mixer and a recording device, which I don't think it's really meant to do.

i.e. your theoretical signal flow should be: modem in to the computer -> use the XP audio device control panel to select "modem in" and route that to your computer's audio out -> connect the audio out to one channel of your mixer -> plug your mic into the other channel of the mixer -> USB out of the mixer -> select the USB codec option as your input in Audacity.

I think you would want to listen via headphones at the mixer, and disable input monitoring in Audacity in order to prevent feedback.

And there's still the question of how to get the audio from your mic back out to the person you're calling down the phone line. Which I think would only be possible via a telephone app packaged with your modem, as mirage pine says, and depending on what the capabilities of that app are. You might need to take an aux out from the mixer to your computer's audio input jack, send just your mic channel to that aux, then use XP control panel and/or a telephone app to route the audio in to the modem.

This is all seeming excessively complicated. . . . . .

3) As far as I can tell, any third-party apps that might allow you to use your computer to make phone calls via standard analog phone lines are long gone. It's all VOIP now, and that would be my other suggestion - use Skype or a similar application to make the phone call (which won't necessarily be free if you're calling a landline), and route it to Audacity to record.
posted by soundguy99 at 6:45 AM on November 27, 2012

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