Zoom H4n and live show major issues

Thomas Moore · June 30th, 2010, 09:28 PM

Well we don't have the truck and I'd still really like to save this thing, plus I need to re-do it if I can't so I don't want a repeat issue anyway, and I'd like to save this footage as there is a lot of good shots in this....

Played with the board feed in Audacity and "think" i've got it balanced at least for what I got. Any ideas on how to make it better?

Jay Massengill · July 1st, 2010, 02:28 PM

I can definitely hear some phasing issues (both within each individual channel and between the two channels) as well as clipping where this test file exceeds full digital 0 level.
I think it sounds much better with the phase inverted on one channel when I split them apart and center each of them.
It's impossible to really know from afar what the mixer is sending you and how they are processing it that may be contributing to these phasing issues.
Plus there could be mixer output and cable wiring phase issues.
This combined with the nature of how the Zoom's built-in mics are going to record the scene with phase issues in relation to the board feed makes it even more complicated.
Just to double-check, you did record originally in at least 16-bit 48k WAV format right?
Some of the problems almost sound like mp3-type audible issues too.
I think if you use the correct pads (or a small mixer) between the board feed and the Zoom to avoid clipping, and can place the Zoom closer to the stage, then carefully adjust the timing of the 2 sets of tracks (smaller than one frame adjustments), you'll hear some major improvement.
If possible, find out exactly what mixer they are using and which outputs. It wouldn't hurt to check the polarity of their output cables too if they'll let you.
Also remember that clipping can occur at both the Zoom's input as well as in its recording level. So if your levels "look" good but you can still hear clipping, then the signal may be overloading the input and this could occur before the recording level controls on the older Zoom H4. With the newer H4n (I have both) I haven't experimented enough to know exactly where the controls take effect since I'm the person who is always feeding it a correct level signal.
It's also possible they could be clipping somewhere on their sound board, which you can't fix at all except to tell them.

Thomas Moore · July 1st, 2010, 02:46 PM

Thanks Jay, yea I didn't hear that at midnight last night when I first did this but yea at work during lunch I listened to it with headphones and picked up the "flanging", didn't notice any clipping though.

I think "phasing/flanging" is coming from my noise removal profile in Audacity I just ran it at default and didn't adjust it.

I'm going to attack it again tonight and I'll put up some test clips....

Yes, I did record 48K/16 bit wav format.

How do you adjust the timing of the two tracks in the zoom?

On try two I'm going to use the TRS cables suggested earlier in this thread.

Thanks!

Thomas Moore

Jay Massengill · July 1st, 2010, 02:58 PM

You're welcome. Yes poor noise reduction can certainly cause unintended time-based audible issues like these too.
When I referred to adjusting the timing between tracks I meant in post-production.
You'll need to be able to shift them on a much, much smaller time scale than 1 video frame, which is extremely coarse when you're talking about phasing issues.
If possible during the next setup, rehearsal and testing, use a slate clap at the main stage mic and later look at the difference in arrival time with the Zoom's on-board mics.

Bill Davis · July 1st, 2010, 03:00 PM

Thomas,

Neither phasing nor "flanging" should come from any noise removal process, period.

Both are TIME based effects.

Phasing takes place when one sound gets out of phase with another and either fully or partially cancels the original sound out.

You can visualize it as two tracks recording a bass note. That bass note drives the cone of the speaker out at 100 times a second. If one of the two tracks gets out of phase such that when the first track is pushing the speaker OUT - the second track is telling the same speaker to pull IN at precisely the same amplitude - and you mix those two signals - what you get is NO SOUND.

Flanging is a form of phasing where originally one dragged a finger or thumb against the FLANGE of a reel of analog tape to slow it down with respect to another playing the same content. That was the mechanical process of moving them out of phase with respect to each other, but it's possible in flanging to "keep up the pressure" such that you combine the phase effect with echo as the reel slows down enough to put the musical bars out of sync along with the track phase. Out of phase is constant. Flanging is out of phase that comes and goes and might include echo.

In practical music, however, there are lots and lots of frequencies in play, so when you get music "out of phase" it affects certain bands more than others and you get that characteristic "thin, whooshy, phasey" sound.

An application that's applying "noise removal" should be digitally re-calculating the audio content of a timeline to reduce the noise - but it would NOT typically be adding any phase effects in any form.

So you've got something else going on that's getting your tracks out of alighment. And yes, that can be as simple as the time delay between the board feed and the delay in your live recording that reflects that time it takes for the sound of the speakers on stage to reach the mics of your recording.

Good luck.

Thomas Moore · July 1st, 2010, 08:20 PM

Thanks for the help guys...

I actually got this to a point tonight where it sounded decent I'm too tired to put up a clip of it, but there was this god awful hiss that I just couldn't get rid of and it was intermittent as well as a 200 hz spike throughout the entire recording - watched it with Spectrum analyzer...

One thing I haven't mentioned in all this and I'm kicking myself for doing it now, is that I used house cables instead of mine which I know are shielded etc, so I'm really starting to think - correct me if I'm wrong, that some of my issues could also have been from the cables. Best way to describe it is a lot of what I feel is EMI interference.

Listened to the other bands input from the board and the vocals are mixed right in with the guitars and pushing to the limit washing everything else out (sob) so I give up trying to save this.

This has led me to decide to do the following:

Buy two Shure SM57's at 99.00 a piece this seems reasonable and will keep me from having this issue again I assume :)

Connect these too one of my camera's as a "saftey net", extra tracks to mix in if the board feed to my Zoom is good, using the TRS to TRS or worse case XLR to TRS cables that I bought (and will recieve tommorow) from Jay's suggestion earlier in this thread.

Here is where I'm really going to show my ignorance, and I need to do this Saturday :)

Earlier Mike suggested putting the Mic's "seperatley mic the PA stack. One on the horn and one on the woofer."

Wouldn't this just give me "one side of the mix?"

Also, how exactly should I place the Mic'?

Steve House · July 2nd, 2010, 07:37 AM

SM57's are close working stage vocal mics, fine when 2 inches from a singer's mouth but not optimum for recording an ensemble from the edge of the stage.

Thomas Moore · July 2nd, 2010, 08:08 AM

Thanks Steve...

From what Mike was saying, and I've found a few other references to doing this on other forums the method is to put them 3" to 1 foot away from the horn and the woofer on the PA stack...

Since there are usually two I'm not sure which one I should be micing for one and the other which no one seems to mention is "right in front aimed at the speaker, in the middle, off to one side, at an angle etc.

I'm assuming on a mic stand pointed directly at the horn, woofer...

Rick Reineke · July 2nd, 2010, 09:35 AM

If the mics are too close to the PA speaker, your going to get pretty much the same instrument-vocal balance as a board feed... just though a speaker. You will have to experiment with aiming and placement to get a good balance of speaker / stage / room.
Another option, If available and the house PA operator does not object, is taking a pre-fader auxiliary out which would give the option of raising or lowering the channels, independent of the FOH mix.. A post-fader aux. out would give you separate mix options as well but would be subject to the channel fader moves by the FOH mixer.

Thomas Moore · July 2nd, 2010, 11:19 AM

Getting the "board feed" from the speaker I believe is what I am going for here as a saftey net for my board feed.

I should be able to get the room/crowd sounds from the onboard mics of the ZOOM by putting it behind the PA cabinet - at a 45 degree angle aimed towards the crowd.

Note I'm typing this to verify as this is what I'm gleaning from all the information being suggested here.

If I get good board feed I've got I've got 4 good tracks to work with, if I don't I have the Speaker mix to use, if both come out good - I've got 4 good tracks to mix from...

Note still asking for verification of my thoughts here :)

I'm actually considering - note which means I probably am - getting another H4N and using that for the PA micing and the other one on the board.

July 1st, 2010, 03:00 PM	#20
Bill Davis Trustee Join Date: Jan 2004 Location: Scottsdale, AZ 85260 Posts: 1,538	Thomas, Neither phasing nor "flanging" should come from any noise removal process, period. Both are TIME based effects. Phasing takes place when one sound gets out of phase with another and either fully or partially cancels the original sound out. You can visualize it as two tracks recording a bass note. That bass note drives the cone of the speaker out at 100 times a second. If one of the two tracks gets out of phase such that when the first track is pushing the speaker OUT - the second track is telling the same speaker to pull IN at precisely the same amplitude - and you mix those two signals - what you get is NO SOUND. Flanging is a form of phasing where originally one dragged a finger or thumb against the FLANGE of a reel of analog tape to slow it down with respect to another playing the same content. That was the mechanical process of moving them out of phase with respect to each other, but it's possible in flanging to "keep up the pressure" such that you combine the phase effect with echo as the reel slows down enough to put the musical bars out of sync along with the track phase. Out of phase is constant. Flanging is out of phase that comes and goes and might include echo. In practical music, however, there are lots and lots of frequencies in play, so when you get music "out of phase" it affects certain bands more than others and you get that characteristic "thin, whooshy, phasey" sound. An application that's applying "noise removal" should be digitally re-calculating the audio content of a timeline to reduce the noise - but it would NOT typically be adding any phase effects in any form. So you've got something else going on that's getting your tracks out of alighment. And yes, that can be as simple as the time delay between the board feed and the delay in your live recording that reflects that time it takes for the sound of the speakers on stage to reach the mics of your recording. Good luck. __________________ Classroom editing instructor? Check out www.starteditingnow.com Turnkey editor training content including licensed training footage for classroom use.

July 2nd, 2010, 07:37 AM	#22
Steve House Inner Circle Join Date: Mar 2005 Location: Hamilton, Ontario, Canada Posts: 5,742	SM57's are close working stage vocal mics, fine when 2 inches from a singer's mouth but not optimum for recording an ensemble from the edge of the stage. __________________ Good news, Cousins! This week's chocolate ration is 15 grams!

July 1st, 2010, 02:28 PM	#17
Jay Massengill Trustee Join Date: Jul 2003 Location: Burlington Posts: 1,976	I can definitely hear some phasing issues (both within each individual channel and between the two channels) as well as clipping where this test file exceeds full digital 0 level. I think it sounds much better with the phase inverted on one channel when I split them apart and center each of them. It's impossible to really know from afar what the mixer is sending you and how they are processing it that may be contributing to these phasing issues. Plus there could be mixer output and cable wiring phase issues. This combined with the nature of how the Zoom's built-in mics are going to record the scene with phase issues in relation to the board feed makes it even more complicated. Just to double-check, you did record originally in at least 16-bit 48k WAV format right? Some of the problems almost sound like mp3-type audible issues too. I think if you use the correct pads (or a small mixer) between the board feed and the Zoom to avoid clipping, and can place the Zoom closer to the stage, then carefully adjust the timing of the 2 sets of tracks (smaller than one frame adjustments), you'll hear some major improvement. If possible, find out exactly what mixer they are using and which outputs. It wouldn't hurt to check the polarity of their output cables too if they'll let you. Also remember that clipping can occur at both the Zoom's input as well as in its recording level. So if your levels "look" good but you can still hear clipping, then the signal may be overloading the input and this could occur before the recording level controls on the older Zoom H4. With the newer H4n (I have both) I haven't experimented enough to know exactly where the controls take effect since I'm the person who is always feeding it a correct level signal. It's also possible they could be clipping somewhere on their sound board, which you can't fix at all except to tell them.

July 1st, 2010, 02:46 PM	#18
Thomas Moore Regular Crew Join Date: Oct 2009 Location: Ravenna, OH Posts: 198	Thanks Jay, yea I didn't hear that at midnight last night when I first did this but yea at work during lunch I listened to it with headphones and picked up the "flanging", didn't notice any clipping though. I think "phasing/flanging" is coming from my noise removal profile in Audacity I just ran it at default and didn't adjust it. I'm going to attack it again tonight and I'll put up some test clips.... Yes, I did record 48K/16 bit wav format. How do you adjust the timing of the two tracks in the zoom? On try two I'm going to use the TRS cables suggested earlier in this thread. Thanks! Thomas Moore

July 1st, 2010, 02:58 PM	#19
Jay Massengill Trustee Join Date: Jul 2003 Location: Burlington Posts: 1,976	You're welcome. Yes poor noise reduction can certainly cause unintended time-based audible issues like these too. When I referred to adjusting the timing between tracks I meant in post-production. You'll need to be able to shift them on a much, much smaller time scale than 1 video frame, which is extremely coarse when you're talking about phasing issues. If possible during the next setup, rehearsal and testing, use a slate clap at the main stage mic and later look at the difference in arrival time with the Zoom's on-board mics.

July 1st, 2010, 08:20 PM	#21
Thomas Moore Regular Crew Join Date: Oct 2009 Location: Ravenna, OH Posts: 198	Thanks for the help guys... I actually got this to a point tonight where it sounded decent I'm too tired to put up a clip of it, but there was this god awful hiss that I just couldn't get rid of and it was intermittent as well as a 200 hz spike throughout the entire recording - watched it with Spectrum analyzer... One thing I haven't mentioned in all this and I'm kicking myself for doing it now, is that I used house cables instead of mine which I know are shielded etc, so I'm really starting to think - correct me if I'm wrong, that some of my issues could also have been from the cables. Best way to describe it is a lot of what I feel is EMI interference. Listened to the other bands input from the board and the vocals are mixed right in with the guitars and pushing to the limit washing everything else out (sob) so I give up trying to save this. This has led me to decide to do the following: Buy two Shure SM57's at 99.00 a piece this seems reasonable and will keep me from having this issue again I assume :) Connect these too one of my camera's as a "saftey net", extra tracks to mix in if the board feed to my Zoom is good, using the TRS to TRS or worse case XLR to TRS cables that I bought (and will recieve tommorow) from Jay's suggestion earlier in this thread. Here is where I'm really going to show my ignorance, and I need to do this Saturday :) Earlier Mike suggested putting the Mic's "seperatley mic the PA stack. One on the horn and one on the woofer." Wouldn't this just give me "one side of the mix?" Also, how exactly should I place the Mic'?

July 2nd, 2010, 08:08 AM	#23
Thomas Moore Regular Crew Join Date: Oct 2009 Location: Ravenna, OH Posts: 198	Thanks Steve... From what Mike was saying, and I've found a few other references to doing this on other forums the method is to put them 3" to 1 foot away from the horn and the woofer on the PA stack... Since there are usually two I'm not sure which one I should be micing for one and the other which no one seems to mention is "right in front aimed at the speaker, in the middle, off to one side, at an angle etc. I'm assuming on a mic stand pointed directly at the horn, woofer...

July 2nd, 2010, 09:35 AM	#24
Rick Reineke Inner Circle Join Date: Aug 2008 Location: New York Posts: 2,039	If the mics are too close to the PA speaker, your going to get pretty much the same instrument-vocal balance as a board feed... just though a speaker. You will have to experiment with aiming and placement to get a good balance of speaker / stage / room. Another option, If available and the house PA operator does not object, is taking a pre-fader auxiliary out which would give the option of raising or lowering the channels, independent of the FOH mix.. A post-fader aux. out would give you separate mix options as well but would be subject to the channel fader moves by the FOH mixer.

July 2nd, 2010, 11:19 AM	#25
Thomas Moore Regular Crew Join Date: Oct 2009 Location: Ravenna, OH Posts: 198	Getting the "board feed" from the speaker I believe is what I am going for here as a saftey net for my board feed. I should be able to get the room/crowd sounds from the onboard mics of the ZOOM by putting it behind the PA cabinet - at a 45 degree angle aimed towards the crowd. Note I'm typing this to verify as this is what I'm gleaning from all the information being suggested here. If I get good board feed I've got I've got 4 good tracks to work with, if I don't I have the Speaker mix to use, if both come out good - I've got 4 good tracks to mix from... Note still asking for verification of my thoughts here :) I'm actually considering - note which means I probably am - getting another H4N and using that for the PA micing and the other one on the board.