-- Hardware Overdubbing/Multitrack - Behringer UCA202 USB Sound Card --



I'm going to describe a known, good, working method of creating a multiple sound track overdubbing session in Audacity 1.3. That is, you record one track and then play it back and add a second track against it. Drums, guitar, voice. Repeat as needed.

This process uses your existing analog microphones, instruments, sound mixer or amp. We are connecting your already working sound system to the computer and Audacity through a special, required USB sound card.

We will use a short audio adapter cable during the system setup and adjustment.

You will hear a useful, theatrical mix of your live performance and the previous tracks in your headphones. This is the step often missing or impaired without purpose-built hardware.



The Behringer UCA202 can be used for overdubbing and sound-on-sound by connecting your computer to your headphones and analog stereo mixer, turntable/CD DJ system, keyboard or other music production equipment.

It will not amplify a microphone or a turntable directly, and it will not work with a USB microphone and may not work with a USB mixer. It will work with a guitar pickup and the right cable adapters.

I'm using a stereo mixer as the example in this talk.

The UCA202 has a headphone connection and when switched to Monitor-On, will mix sound from the computer playback with live performance sound. This is the mix you need to sing or play to yourself with no latency, echoes or other impairment.

The mix is half-and-half and you can't change it, so it may take some doing to get the headphone mix just right as you perform.


Almost any PC, Mac or Linux machine with fast enough USB and good storage can be used.

I'm using my Mac earbuds for listening in this example, but nearly any good headphone or earbud is OK. If you require cranium-crusher headphone volume, you may need a headphone amplifier. You must get the headphone sound from the UCA202, not the computer sound card.

Headphones are good. Live microphones and live speakers in the same room do not get along.

I'm using Audacity 1.3.13. Audacity 1.2 is more difficult to use, is not well supported, and can be unstable.


The Behringer UCA202 has three jobs:

-- It converts the mixer's stereo analog show to digital and sends it down the USB cable for recording.
-- It converts the USB digital show from the computer back to stereo analog.
-- It has an internal headphone mixer. The UCA202 can mix your existing track playback and your new, live performance so you can listen to both.



We will do a simple recording. No overdubbing or other fancy tricks. The system has to work correctly for simple recording and playback before we go further.

Connect the USB, headphones and mixer. The UCA202 must have a USB Home Run to the computer. USB audio will not go through a hub or long USB extension cables.

The UCA202 must be connected before you start Audacity.

I'm using my sound mixer Tape-Out for the connection.


This is not a tutorial on making a recording and playing it back, but you need to be able to do that before you do anything else. There are multiple tutorials and wikis on Recording.

Audacity Manual
First Recording
General Workflow

Set the computer control panels, preferences and Audacity drop-downs to recognize the UCA202 USB device for both stereo recording and playback. The UCA202's name is USB audio CODEC.

Set Audacity Preferences:

Audacity Preferences > Quality > 44100, 32-bit Floating.
Audacity Preferences > Devices > Stereo.
Audacity Preferences > Devices > Recording and Playback to the USB sound device.

Audacity Preferences > Recording (you may not have all of these settings)

[X] Overdub...
[  ] Hardware Playthrough...
[  ] Software playthrough...

OK > Restart Audacity.


When Audacity starts, expand the sound meters by clicking on the right edge and dragging to the right. The rest of the tools and panel graphics will move out of the way.

Click once anywhere inside the red recording meters to put them in Monitor Mode. They will measure the live show sound without sending Audacity into full record and wasting drive space. This may fail on certain linux machines using Jack.

Switch the UCA202 Monitor to ON. The UCA202 has no volume controls for the show in either direction. The volume has to be set at the mixer or amp. The only UCA202 control is headphone volume.

Play a record, play an instrument, or sing through the mixer. Don't peak much over -10 to -6 on the Audacity meters. You can fix funny levels later, but you cannot fix overloading, smashing, and clipping (meters too far to the right). You should be able to hear your performance in the headphones. Adjust the UCA202 Volume control as needed for comfortable listening.

Press Record. Audacity will take a second to configure itself and start recording. The blue waves will start to crawl left to right as you perform. Play, sing, or perform a simple song that you can use for rhythm and timing later.

Press Stop, Home. Play the track you just made. You should hear the track in your headphones. If your mixer makes a sound, you will hear that, too. The UCA202 headphone connection features a non-adjustable 50:50 split between live volume and playback volume.

This is what you will hear during the overdub sessions. Any combination of existing tracks will play in your headphones in addition to your live performance allowing you to set a good theatrical or musical mix and timing.



Home the cursor and Press record again and you will get a new recording underneath the first one. Sing or perform in time to the first track. Press Stop, Home.

The show will have two tracks, one from each performance, but it may be seriously out of time or rhythm -- even though you were in perfect time when you recorded it. This is Recording Latency and you can adjust it to zero using Audacity 1.3 Latency tools.

Done properly, both the live recording session and the playback later will be in perfect time.

File > Close > Don't Save


File > New

Generate > Click Track > OK.

Audacity Preferences > Recording > Latency Correction [ 0 ] milliseconds . . . > OK.

Unplug the headphones. Turn the UCA202 headphone volume about 2/3 of the way up. Switch the Monitor to OFF.

Plug an audio adapter cable between the Headphone of the UCA202 and the Line-In.

Press Record.

Track one's click track is now being recorded onto track two through the adapter cable. Good fidelity or volume is irrelevant.

Do that for five or ten seconds and press Stop.

Reduce Volume a bit and plug the headphones back in and put them on.

Select the new track and Effect > Amplify > OK.

Play and both tracks will probably play out of step.

Magnify the timeline around one of the pair of clicks (drag-select and Control-E or Command-E.

Drag-Select the distance between the start of the click on the top track and the start of the same click on the bottom track.

That's how much the rhythm misses and that's the recording latency. Keep magnifying until you can get a good shot at accuracy. Control-3 or Command-3 to back out slightly if you magnify too much by accident.

Bottom of the screen > Middle Time Window > Length

Change the format using the dropdown menu to:

hh:mm:ss: + miliseconds.

You're mostly interested in the milliseconds -- the last numbers on the right. The difference between my clicks was 244 msec.

Audacity Preferences > Recording > Latency Correction [-244] milliseconds . . . > OK.

Restart Audacity and go through generating Click Track again. Plug the adaper cable back in, etc.

This time the two click tracks should look perfectly on or very close to it, and sound perfectly in time. If not, zoom in, measure the new difference and add that number to the latency value.

Before you get too obsessive about this, an orchestral musician once told me that the chances of any two instruments in the orchestra starting the same note at the same time is zero, so you don't need to adjust things down to the digital sample level. The latency values on home computers can wander in normal use.

Remove the cable. Plug the headphones back in.



Restart Audacity (you don't need to save any of your tests) and you're ready for the first theatrical session.

Switch the UCA202 Monitor to ON.

The first recording can be whatever you're planning to use as a base, backing, guide or rhythm track. It can be anything including Generate > Click Track which can be adjusted with its control panel for rhythm and composition. I used music from my rhythm and chord machine playing to the mixer.


You should record a lead-in. That is, a non-musical rhythmical clue when to start before the music starts. In a live band, this would be the drummer or lead guitar count-in. I used the keyboard rhythm stops in my tests, but you can perform several rim shots into the mixer's microphone to establish the rhythm before the first note. Tapping on the table with a pencil works. Keyboard notes. Anything. You can sheer it off in post production later so nobody else will hear it.

Tick, tick, tick, tick, Music. Adjust as appropriate for music type and rhythm.

Stop > Home the cursor, press record and record track two using your live performance and track playback in your headphone mix as a guide. Repeat until bedtime. Lay in supplies. Once working, this is seriously addictive.

The Mute and Solo buttons to the left of each track are valuable in overdubbing. Solo causes only that track to play and Mute turns that track off. Solo has options. The little volume control to the left of each timeline also controls the playback volume -- it affects the headphone mix.

When you get to a stopping point, press Stop and File > Save Project As. As you progress, you should save a new Project periodically with a slightly different filename. I don't use a kitchen timer, but I probably should. Being obsessive, I use ISO date and time for the filenames.


That's today at 3PM. October First, 2011, 1500hrs. If you glaze over at that, you can put dashes or underlines in 2011-10-01-1500.aup. You MAY NOT use standard date formats like 10/01/11

I will never duplicate a file by accident short of a typo. Do Not Use Slash Marks or other punctuation marks in a filename. I have to send work to many different computer types, so I don't use spaces, either.


New version of the song about every twenty minutes.

Do Not go weeks with one Project and filename, and never cover up or record over existing work. If anything happened to that one Project, you'd be dead and could take weeks of work with you. Think of what would happen if the lights went out right now, the computer ground to a halt and you were forced to use the last known good version of the show.

Audacity Projects are brittle, easily damaged and do not save UNDO.

Export to WAV for archive and Music CD, or MP3 for internet delivery or email. Do Not do production in MP3.

You may need to adjust the volumes and levels of the show so the Export doesn't overload.

All of the Audacity editing, filtering, and effects tools are available for each track or any combination of tracks before or after you sing/play. But not during. Audacity will not apply filters and effects in real time.



How much hard drive space do you have? If your only experience with computer files is with spreadsheets, email or Photoshop pictures, live audio (and video) production will stun you. Particularly with high quality overdubbing and UNDO, those project files and folders get big in a hurry, and with periodic saving, a project can get very seriously large.

Newer Windows machines in particular are openly hostile to entertainment production.
My music changes volume by itself and sounds tinkly/hollow

You can't send audio through a self-powered USB hub or share any hub, ever.

Except in rare circumstances, you can't plug a Stereo analog sound mixer directly into a Windows Laptop for recording. Mic-In (many times pink) is mono, not stereo, and too sensitive for the mixer. The UCA202 neatly gets around that problem even if you're not planning overdubbing or complex production.

The headphones must be plugged into the UCA202 for overdubbing, not the mixer and not the computer. The mixer will not present the computer playback and the computer sound will be late (off rhythm) and you can't change it.

It's certainly possible to do a credible overdubbing job without specialty hardware -- in software only -- but it can take very serious programming effort and some knowledge of how the inside of your computer works. If compiling binary libraries is too much for you and the hardware devices are inappropriate, you could always write a check to buy a commercial sound mixing program.

If no matter what you do the show sounds terrible or doesn't work at all, do drop in to the Audacity Help Forum where the elves and I will try to dig you out of trouble. Registration is required but free, and we may make you wait before your posting appears to the public.

At minimum, you will need to tell us exactly which Audacity you're using, what kind of computer you have and which operating system. I use Audacity 1.3.13 on a Mac Mini with Snow Leopard, OS-X 10.6.8. Don't head straight to the details of the problem without telling us what you're producing and why.

Be prepared to tell us how the straight recording session went -- the one you did before you tried overdubbing.

Please don't post pages of diagnostic dump or error log unless we ask for it. If you do insist on posting it, use the [data] tags.