17 Replies Latest reply on Jun 24, 2009 6:25 PM by Jim_Simon

    Mono speech

    ptelian Level 1

      I have two questions:


      I have heard that speech (interveiws) should be mono (front and center). Is this true?


      If it is, what is the best way to convert my stereo interviews to front and center mono? I have done Edit>Convert Sample Type in Audition, but for some reason that is not always giving me the right results.



        • 1. Re: Mono speech
          Harm Millaard Level 7

          When you are talking about front, center, I assume you are talking a 5.1 master track. Correct? If so, use the audio mixer and put the puck in the center box.

          • 2. Re: Mono speech
            ptelian Level 1

            Actually, it's a stereo master.

            • 3. Re: Mono speech
              Harm Millaard Level 7

              Then why are you bothering? Stereo is the output anyway at the minimum.

              • 4. Re: Mono speech
                ptelian Level 1

                I'm bothering because of this. And I tested one DVD where I did the "Convert Sample Type" in Audition...and it worked.


                But before I changed my whole project to mono, I wanted to confirm that speech indeed should be mono.


                I tried the fill right/fill left, but that droped the volume way down and made it scratchy (duplicating the issue I hear on the DVD player.

                • 5. Re: Mono speech
                  Harm Millaard Level 7

                  Sorry to be blunt, but if you still record 32 KHz 12 bit, you haven't got it. Start reading the manual or help file.


                  Otherwise, your message makes no sense. It really is nonsense. If you shoot 48 KHz 16 bit audio, which is stereo, you capture, it is still stereo and you can only export stereo (or 5.1, which is not the case) and none of the issues you mentioned will occur, unless there is again a case of OE.

                  • 6. Re: Mono speech
                    ptelian Level 1

                    What does sample and bit rate have to do with the sound dropping out though? And I can't go back and change what I've recorded.

                    • 7. Re: Mono speech
                      Harm Millaard Level 7

                      If I need a drill to make a hole, it is not effective to use a saw. Wrong tool for the job at hand. In the opposite direction, if I need to cut down a tree, a drill makes no sense, but a saw would be advisable.


                      Without further details, I have to assume, based on previous info given by you, that you don't understand the basics of video editing. It may help to get a basic education.


                      There is no need for speech (interview's and the like) to be mono.

                      • 8. Re: Mono speech
                        ptelian Level 1

                        I do understand the basics of video editing. But I admittedly don't understand all the technicalities of video editing. But I am learning.


                        Here is what the guy said...


                        Compare your film’s speech with pretty much any other film’s, and you’ll notice that normally if someone is on screen speaking, they’re front and center (mono). Your film’s speech is only audible at far right and far left.

                        • 9. Re: Mono speech
                          Dan Isaacs Level 2

                          But… the original poster is correct. There is some kind of strangeness with mono tracks in sequences with stereo masters. The level is cut by about -6dB and, as far as I know, there is no way to simply replicate the mono channel at original volume to both left + right channels…


                          …other than to create a second mono track, copy + paste all the clips, pan one track hard left, the other track hard right.


                          But this is a ridiculous way to try to edit.


                          The best way (and what I do) is to pre-convert your mono tracks to stereo in an audio program.

                          • 10. Re: Mono speech
                            Harm Millaard Level 7

                            This reviewer obviously used a 5.1 audio set to listen to your stereo sound and that makes sense. When you output stereo and play back on a 5.1 sound system, you can never get the signal only from the front center speaker. That requires a 5.1 master track (and the Surcode plugin) and the solution I provided in post #1. However, this is not a general rule. Imagine a speaker in the left side of the screen, commenting on something happening in the right side of the screen. In that case I think it could be quite normal to have this commentator's voice come from the left front speaker. Your audio and visuals should strengthen the illusion of space. The audio mixer is a good tool to do that. Just imagine you have a mono directional mic on your camera and a bus is passing by. Obviously you only have mono sound from this mic, but you can create a sense of direction by using the puck to move the sound from left rear to left front to right front to indicate the bus coming from behind and moving from left to right.

                            • 11. Re: Mono speech
                              ptelian Level 1

                              This may put somelight on the issue...

                              My workflow:

                              Record interview with mono shotgun mic > Audio records to tape on both channels (32kHz 12bit) > Video and audio edited and transoded for DVD > DVD plays with audio issues on some players (audio barely audible on the interviews shot with that mic) > Go back to Premiere and Audition > Convert the audio to mono in Audition (Left Mix 100%, Right Mix -100%) > Test in same DVD player > Issue fixed.

                              • 12. Re: Mono speech
                                Harm Millaard Level 7

                                Why do you still use 32 KHz 12 bit audio, when everybody advised against that approach?

                                • 13. Re: Mono speech
                                  ptelian Level 1

                                  No way, I'm done with that format!


                                  I just have all this footage I shot before I changed it...

                                  • 14. Re: Mono speech
                                    the_wine_snob Level 9

                                    If I remember correctly, you have Audition.


                                    Open your stereo file in Audition and choose Edit>Convert Sample Type (F11), choosing 48KHz 16-bit and in Channels, choose Mono. Leave Left Mix and Right Mix at 50% each. Save_As and name/locate your new PCM/WAV file.


                                    Back in PrPro, Import your WAV and place two instances of it into separate mono Audio Tracks. In Audio Mixer, I'd bias the Balance about +24 Right for one and -24 Left for the other.


                                    If your Gain is not quite where you want it, add a Sub-mix Audio Track and route these two AT's to it. Adjust the Gain with the Audio Mixer (will be Track Keyframes). Leave the Sub-mix to route to the Stereo Master.


                                    Hope that this helps.


                                    Good luck,



                                    • 15. Re: Mono speech
                                      ptelian Level 1

                                      Thank you for the reply Hunt.


                                      What would be the advantage of putting a 50% on two channels (as opposed to an 80-100% on one)?

                                      • 16. Re: Mono speech
                                        the_wine_snob Level 9

                                        Maybe I missed something in the thread, but if I understood, you have a stereo file of speech. If you want to get get each of those tracks into one, unless you wish to bias the resultant file for some reason, you'll want each to contribute to half the mono track. Now, if you do need to bias (your ears would tell you this), you can alter those defaults. Maybe you're picking up some other sounds on one of the channels, and wish to diminish that/those to some degree. I did not recall any problems with the mic or with the mic'ing technique. If you go above a combined % of 100, you will very likely get clipping. Now, if the Gain of your stereo track is very low to begin with, you can probably increase the Gain by going more than 50%/each - just be very careful and look (and listen) at the Waveform in Audition. You do not want clipping, or you'll be doing it all over again.


                                        Good luck,



                                        • 17. Re: Mono speech
                                          Jim_Simon Level 8

                                          When you output stereo and play back on a 5.1 sound system, you can never get the signal only from the front center speaker.


                                          I do it all the time with the Fill effects.  Works great.  (You do need to use a matrix surround mode on the receiver [Dolby Pro Logic, DTS Neo 6], but such is the norm for DVD playback anyway.)