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  #1  
Old 10-04-2002, 07:00 AM
JLEpperson JLEpperson is offline
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Default Bass Tracks out of phase

I recorded bass on 2 tracks using direct thru the avalon 737 and a ampeg amp. I thought there was no phasing problems, but after the tracks were recorded I now having phasing. What can I do to fix this? Is there a plugin that will help?
Thanks
JE
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  #2  
Old 10-04-2002, 07:39 AM
Bob Mould Bob Mould is offline
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Default Re: Bass Tracks out of phase

You need to time align your Basstracks, either delay your direct track to match the phase of your miced track or you can nudge the direct track backwards until they are in phase.

good luck
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  #3  
Old 10-04-2002, 08:32 AM
where02190 where02190 is offline
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Default Re: Bass Tracks out of phase

the above post is incorrect. time alignment does nothing for phase.

If indeed they are out of phase, that is one track is inverted with respect to the other, apply a 1 band eq, and click the phase reverse button in the upper right hand corner. (apply, don't insert, to prevent latency.)

Once that is done, then check time alignment. If both waves do not line up along the timeline the same, shift the mic back by dragging it until it does. (you may need to delete a few ms at the beginning of the track to do this, but that should not be a problem unless you started recording the exact moment the bassist started playing.)

This method is a common practice here, going both direct and micing our '62 Ampeg B-15-N. The DI is often phase inverted from the Amp, and the mic is always a few ms behind the di. Once aligned, you will have yourself one kick *ss bass sound.

If your amp is inverted, you might want to check the phase of the speaker cabinet.

Hope this is helpful.
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  #4  
Old 10-04-2002, 10:49 AM
s2n s2n is offline
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Default Re: Bass Tracks out of phase

Or, use the AudioSuite Invert plugin.
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  #5  
Old 10-04-2002, 03:28 PM
where02190 where02190 is offline
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Default Re: Bass Tracks out of phase

If you select the track and apply, the plug in becomes part of the track. If you insert, ithe digital track goes through the virtual audio path, and you get latency.

If you know you are going to not want to revert back once saved, (like in the case of phase reversed tracks like this) Applying not only aviods latency, but saves CPU power for other plugins.

Hope this is helpful.
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  #6  
Old 10-04-2002, 05:12 PM
Mark Staples Mark Staples is offline
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Default Re: Bass Tracks out of phase

In other words, use the AudioSuite plugins and process the file.
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  #7  
Old 10-04-2002, 05:17 PM
Bob Mould Bob Mould is offline
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Default Re: Bass Tracks out of phase

Quote:
Originally posted by where02190:
the above post is incorrect. time alignment does nothing for phase.

If indeed they are out of phase, that is one track is inverted with respect to the other, apply a 1 band eq, and click the phase reverse button in the upper right hand corner. (apply, don't insert, to prevent latency.)

Once that is done, then check time alignment. If both waves do not line up along the timeline the same, shift the mic back by dragging it until it does. (you may need to delete a few ms at the beginning of the track to do this, but that should not be a problem unless you started recording the exact moment the bassist started playing.)

This method is a common practice here, going both direct and micing our '62 Ampeg B-15-N. The DI is often phase inverted from the Amp, and the mic is always a few ms behind the di. Once aligned, you will have yourself one kick *ss bass sound.

If your amp is inverted, you might want to check the phase of the speaker cabinet.

Hope this is helpful.
<font size="2" face="Verdana, Arial">about my post beeing incorrect IS incorrect!!
Sure time aligning affects phase relationships.
How would you explain what happens (as in this case) if you slowly nudge the DI basstrack against the Mic'ed track while playing, you can clearly hear the phase relationship between the signals change.

/mike
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  #8  
Old 10-04-2002, 05:51 PM
where02190 where02190 is offline
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Default Re: Bass Tracks out of phase

If one of two identical signals are shifted in phase by 180 degrees(phase reversed), there will be absolutey no shift in time.

This has been discussed to death the past few weeks, and if you don't get it you should consider another career or hobby.
The example in question regards two two distinctive principles. First, phase alignment. either both tracks are phased positive, negative, or one of each. We correct the negative one.

Now we align the two positively phased tracks so they are identical.

Hope this is helpful.
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  #9  
Old 10-05-2002, 01:25 AM
STR STR is offline
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Default Re: Bass Tracks out of phase

Hey where02190 Could you explain apply vs insert? Thanks, Steve
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  #10  
Old 10-05-2002, 06:16 PM
Bob Mould Bob Mould is offline
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Default Re: Bass Tracks out of phase

Quote:
If one of two identical signals are shifted in phase by 180 degrees(phase reversed), there will be absolutey no shift in time.
<font size="2" face="Verdana, Arial">Have i said that it would?,
If that would be the case that one of the tracks is of opposite polarity Yes you should flip polarity ("phase reverse") on one track to make both tracks positive or negative, preferbly postive. BUT!! in the case of combining a DI signal and a Mic'ed signal you would still be out of phase to some degree due to the Mic track is slightly delayed to the DI track. So you would need to time/phase-align the tracks to get them in perfect phase. So..obviously timealignment affects phase.
Out of phase doesnt mean that your always 180degrees off, it can be anywhere between 0-180degrees. So flipping polarity doesnt automatically make you in phase.

Quote:
This has been discussed to death the past few weeks, and if you don't get it you should consider another career or hobby..
<font size="2" face="Verdana, Arial">hey!..take it easy buddy, no need for personal attacks here. If you have doubts in my abbilities as an engineer then fine i really dont care. I know that youre a knowledgeble guy and has contributed alot this forum, We are both basically giving the same solution to this problem but is describing it in different ways. But you choose to be ignorant.

Quote:
The example in question regards two two distinctive principles. First, phase alignment. either both tracks are phased positive, negative, or one of each. We correct the negative one..
<font size="2" face="Verdana, Arial">I would call that matching polarity, as that is what you do. Phase aligning is when you alter the phase relationship between two singals of the same source by moving them in time relative to eachother. Theres a little gadget that does this in the analog world called Little Labs IBP. http://www.littlelabs.com/ibp.html
Check that site out there's a very informative description there. Basically what it does is delaying the DI signal by a user set parameter to the mic signal, and thus you can variably change the phase relationship between the two signals. Thats exactly what we do when we time/phase align tracks in the digital world,.

Quote:
Now we align the two positively phased tracks so they are identical.
<font size="2" face="Verdana, Arial">The waveforms will most likely never look exactly the same between a DI signal and a Mic'ed Cab signal. Therefore time/phase aligning the tracks is hard to do by just looking at the waveforms, A good place to begin is to match the start of sound in the waveforms, But you could just aswell move the tracks in real time and listen for when the tracks sound the fattest together and you would probably be pretty close to be absolute in-phase.

/mike
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