Sync radio audio broadcast with television video broadcast


How can I configure audacity as a audio delay processor. While recording or not.
To sync live radio audio broadcast with the live television video broadcast.

Live sports events television broadcast usually have a 1 to 8 second delay.
My live local radio broadcast is pretty much real time of the same event.
I would like to delay the live local radio audio broadcast so it matches what is transpiring on the live television video broadcast.

I figured out how to do this with audacity but can’t remember how I did it.
Kind of like turning your radio into a digital video recorder but just recording audio.
With the capability to time-shift.

Any Idea appreciated,


Software Playthrough” (Transport menu) routes audio from the input to the output via software, which is relatively slow and so delays the output, usually by about half a seconds, but the delay in unpredictable as it depends on the computer and the sound card and many other factors. “Software Playthrough” can not be used at the same time as recording “Stereo Mix” as that will cause a loud howl or squeal.
There is no precise method for accomplishing this task in Audacity - this is just a “quirk” that may (or may not) work for you.

What about adjusting latency.
Or pausing to sync while recording in Software Playthrough. not using “Stereo Mix”
Just an idea, I thought I able to do this by backing up audio while I was recording.
I’m missing something I did, because it wasn’t that hard to be able to do.
Maybe it was a variable audio delay sync feature in the sound card.

Thanks for reply,

Latency adjusts the delay that Audacity applies to the show being written to the hard drive. It’s purpose is to “tune out” the difference between your old track headphone signals and the creation of the new voice track ( assuming the voice is the new track). It doesn’t appear as a live feed.

We went round and round with this at work. We ended up using an old give-away version of a much larger audio program (Bias??) and cleverly ran its delay tool in real time. I know it made my head hurt at the time we were doing this because I couldn’t follow the sound pathways.


But there are two latency fields, only the second is for the latency correction.
Maybe the “Audio to Buffer” does such a delay if set to 1500 ms, haven’t tested though.

On Windows machines I’ve had, “Audio to Buffer” delays playback but not doesn’t delay recording.

Audio to Buffer doesn’t delay playback when software playthrough is enabled, even if you are playing but not recording. Audacity uses a pre-determined buffer setting when software playthrough is enabled.

Have you tried this program ?


Hello Gale,

I know of the above software you mentioned. Here a demo on YouTube of it
Here is another. Audio Delay - Delay Radio Broadcasts - Sychnronize TV and Radio I believe they both have record feature.
I have not tried them. If I did, would I be able to record the delayed signal through Audacity.

Below are some hardware related units:‎

It seems I was able to delay thru Audacity by moving the timeline somehow.
Like going into the minus 1.0 area on the timeline, but I can’t recall on how to start below 0.0 mark on the timeline.

Thanks for Reply,

Minus time is a forbidden place. Sometimes special effects will push a sound track into negative time and the show may become unstable. You can push everything else later in time rather than trying to achieve earlier.

You can certainly match multiple track times up in post production with the Time Shift Tools. Audacity doesn’t do well in real time.


You can do that “after the event” using the Time Shift tool.

Hello Steve,

I stumbled upon this software that has the ability to Time Shift while recording.
This is what it says:The Time-shift feature enables you to listen to recorded sound while a recording is being made. While listening, you can move anywhere within the recorded part of the sound stream and start playback. This feature is available for both ordinary recordings and when background recording Internet streams.

I do not know if this is a common feature with digital audio editors.
Certainly would come in handy.
Wonder how hard it be to implement into audacity.


I don’t know but it would be very related to the capabilities of the PortAudio library we use for Audio I/O.

I can add your vote for such a feature in Audacity.


In principle, yes if you can record computer playback .


Hello Gale,

You definitely can add my vote for such a feature in Audacity.
An example would be:
If you did not hear something correctly, you could back up the cursor/progress bar into the recorded part of the sound stream and play it again.
Then have a “Real time” button to click which jumps the cursor/progress bar back to the beginning or to “Real time” recording.
This would be a very unique feature.

There are a lot people that would rather listen to the local radio broadcast and sync-up the audio with the digital television processing lag time.
DirecTv and Dish network DVR satellite receivers have what is called a “Live Buffer” that automatically and temporally stores up to 90 or 120 minutes of audio video on to the hard drive. If you change channels you lose the “Live Buffer” unless you save it to the hard drive.
For some reason no one has done this with a radio receiver. To do it you would have to convert the analog radio signal to digital, put it on the hard drive then convert it back to analog. Maybe its not feasible.
It not the recording feature that’s the most important, its the ability (After you say to yourself) “What did they say” to go back into the live buffer and hear the sound bite again.That’s the most important.

I don’t think Capture Streaming Audio. Recording, converting, editing of sound. should call it time shifting.
That implies recording and listening at a different time.
It should be called Live Buffer Review or Live Sound Stream Review or Recorded Sound Stream Playback
Audacity would garner a lot attention with this feature.
The only question is how hard would it be to do?

Thanks For the Reply,


OK it will be added.

Audacity of course stores the recording as digital data on the hard drive.

Audacity currently lets you hear what you are recording by sending a delayed copy of the input to the output (software playthrough) but the delay is not configurable.

So you have two choices. You can hugely increase the buffer so you can somehow navigate it. This probably means you then won’t be able to play anywhere near the current live point of the stream. It also relies on the computer having copious amounts of RAM.

Or you can play the audio you have already recorded from disk. This means given Audacity’s current audio data block size that the part you can play will always be up to six seconds before the live point that’s recording. You could reduce the block size but it would tax slower computers and risk recording damage.

I don’t know what Total Recorder does exactly. I guess it’s reading from disk but I don’t have time to play with that right now. Peter may know what it does.