Overdubbing - 2nd recording sounds "phase shifted"

JimLewandowski · 04 Feb 2011

On my old Xp, using a cheapy microphone (plugged into sound card), I successfully overdubbed one guitar part onto another with no perceived loss in quality. I had a SB card and used "record what u hear" which I assumed took it directly from the card BEFORE it hit the speaker (i.e. it's recording the amalgam of any sound from the PC that hits that sound card at that instant).

On my W7 PC (integral soundcard), I have tried BOTH a webcam and a 3.5mm soundcard direct microphone.

So, I record 5 seconds of guitarplaying using either Sound Recorder OR my Logitech Webcam software (muting the video).

I then play that 5-seconds using WINDOWS EXPLORER preview and then record that again (adding NO other part). Using either webcam or the 3.5mm microphone, the second recording comes out horribly phase shifted (you almost can't tell its a guitar).

Any suggestions? I've tried all the combos I can think of. I have BOTH speakers and recording set to 192000-bit (i.e. they match).

Additionally, on my sound RECORDING tab, what is SPDIF? Is that akin to "what u hear"?

Johnathan Lyman · 05 Feb 2011

My guess there's a signifcant latency in the sound card hardware, most likely because it's onboard audio and not a dedicated sound card.

Second, S/PDIF is a data link layer protocol and a set of physical layer specifications for carrying digital audio signals between devices and components over either optical or electrical cable. The name stands for Sony/Philips Digital Interconnect Format
(source S/PDIF - Wikipedia, the free encyclopedia)

fireberd · 05 Feb 2011

As noted it's a "latency" issue (delay). Those of us with computer based recording studios (I use Sonar) are very painfully aware of latency.

There is a delay from what you are hearing and then playing along with (recording). The lowest latency I can get (total) is 5 ms with an MAudio Fastrack Ultra8R USB connected audio interface.

Run the DPC Latency Checker HERE and see what your system shows.

JimLewandowski · 05 Feb 2011

whats my solution?

can i run some jumper to sound card to feed

output signal + mic to a point where i worrk around delay?

fireberd · 05 Feb 2011

Other than a different input sound device (with low latency) not much choice. If you had a recording program where you could record the first take on one track and the second one on a different track and then sync the tracks that would work.

But, with just the PC sound and a simple recording program you are not going to be able to do what you want.

JimLewandowski · 05 Feb 2011

What about Audacity software?

wouldnt that allow 1 track to be recorded then another

and then edited/synched together?

It seems the 3.5m mic doesn't have much phase-shifting vs. the webcam (webcam is USB, i.e. polled by software so not as instantaneous??).

By phase shifting I mean previously not the WHOLE overdub but the phase shift would come and go in a semi-rhythmic (slow) pattern.

I ran that latency checker andit shows 120 usec average and max 170.

fireberd · 05 Feb 2011

120 is a lot of latency and would account for your problems.

Audacity has the capability to do what you want. It will "align" tracks. I have the "beta" version.

JimLewandowski · 05 Feb 2011

so with audacity, I could record let's say 5 "pieces" of a song.

Then I could stitch/edit them all together with correct timing and everthing?

Then later I could play the final 1st track and then play ALONG with it to create a final 2-track recording?

Right now I have to sit in WMP, open Sound Recorder and stitch things together by ear. I have to hit "repeat" on just the right part of the WMP progress bar to get right back to the beginning of measure. Then I have to play it ALL back again and then add on my next part and so on so forth. Slow.

Ok, I downloaded Audacity. I import the audio from a WMV file. It shows up. When I click "play" it just goes "tick" and plays for 1 millisecond. How hard can this be? Surely you can PLAY the whole track you JUST imported.

Ah, I see. It imported a 15-second .wmv file's audio as lasting only a tenth of a second.

fireberd · 05 Feb 2011

I don't use Audacity so I'm not up on it. But, it's a very popular recording program. play around with it and try recordings and see what happens.

Johnathan Lyman · 05 Feb 2011

I, personally use Adobe Soundbooth CS5 for my recording. I find it very powerful and suits my needs very well.