Checking phase using Logics Multi Meter?

[Eric Wikman]

I have a friend with a very nice studio. He has a unit across his outputs, that constantly shows phase issues.. if any.. for setting up mics etc.

 

I would like to know if & how I can use Logic's Multi Meter to do the same, or is it not that useful? I see there are 2 meters for checking.

 

I have not done many multi mic recordings, so phase in this case has not been much of an issue for me so far.

I'd like to learn more though, by trying this here first.

So, for a simple set up. I recorded a bass direct, and the same signal multed .. and recorded from an amp w/ a mic.

Now I know I can line up the waveforms by eye, but, what would be the procedure for aligning any time/phase differences between these to takes?

Since Logic checks for Stereo phase, would I pan each bass track hard left & right... and then look at the meter.. and adjust?

Maybe I far off here?

I know that the blend of the two tracks can be anywhere that sounds good, but I'm just looking for technical advice & real world usage.

Thanks

[Ashermusic]

I have a friend with a very nice studio. He has a unit across his outputs, that constantly shows phase issues.. if any.. for setting up mics etc.

 

I would like to know if & how I can use Logic's Multi Meter to do the same, or is it not that useful? I see there are 2 meters for checking.

 

I have not done many multi mic recordings, so phase in this case has not been much of an issue for me so far.

I'd like to learn more though, by trying this here first.

So, for a simple set up. I recorded a bass direct, and the same signal multed .. and recorded from an amp w/ a mic.

Now I know I can line up the waveforms by eye, but, what would be the procedure for aligning any time/phase differences between these to takes?

Since Logic checks for Stereo phase, would I pan each bass track hard left & right... and then look at the meter.. and adjust?

Maybe I far off here?

I know that the blend of the two tracks can be anywhere that sounds good, but I'm just looking for technical advice & real world usage.

Thanks

 

I guess you could adjust the anchor point in each region so it is exactly where sound enters and then make sure that the regions are in exactly the same position in the Event Editor but if you cannot hear phase issues then I think you are overthinking it personally.

[David Nahmani]

I agree with the overthinking comment. You are trying to time-align track, and you certainly don't need a phase meter for that. Your answer is contained in your original question: just align the waveforms.

 

After experimenting quite a bit with various rock bass recording setups, I came to the conclusion that DI recording is the solution. I have never gotten anything good out of a microphone on a bass amp.

[Eric Wikman]

Hey guys,

No over-thinking here. Just trying to expand my knowledge.

 

Thanks for the replies, but l meant from my post that this was just for example... and I have no trouble lining up two bass tracks in other ways.

The sound of the Bass is not my issue here.

I'd just like to learn how to use Logics tools better. (MultiMeter checking for Phase if poss).. for that day when I need them.

 

We did a perc session with a guy who plays with Issac Hayes. My friend has about 75 mics, and we set up 4 of them to capture the session... with the intent to choose the best recording (or blend) later. He uses the phase meter to look at his mic set up, and can see if there are any issues right then, and walk into the booth and adjust the distance of the mics to get the best phase result.

I am trying to see if I can do similiar check & adjust (besides my ears) using these tools.

 

And BTW, from my reading of books (booksmart eh?), I'd say I see 75% (rough guess) of famous producers use a blend of DI & amp'd for bass. I had always used DI before.

 

Boy "typing" is hard to get a precise message across sometimes. I find myself thinking and re-thinking posts, but most the time, I have to elaborate further.

Thanks for your time & knowledge.

[David Nahmani]

Like you've mentioned, the multimeter checks the phase correlation between the left and right signals from a stereo signal. It is a great tool to visually check for mono compatibility of a stereo instrument or stereo mix (total phase correlation = +1 means a mono signal. The stereo width widens as the correlation approaches 0, and below 0 you start going out of phase). You can also use the goniometer (a mono signal is represented by a vertical line on the M line, anything that starts spreading toward the sides indicates stereo width).

 

Keep in mind that the goal is neither to totally correlate your phase (you end up with a mono mix) or totally widen the stereo (your mix gets harder to be mono compatible), but rather to find a good balance.

 

In your case (Bass DI + Bass amp recorded through mic), you want to time align the signal, which is quite different. When signal are not time aligned, the phase correlation changes with each note pitch, as a constant time difference results in a phase offset that is a function of the frequency of the signal. So a phase meter would not be the right tool for the job, although you could still keep it open to watch what happens to your phase before and after you time align.

[David Nahmani]

And BTW, from my reading of books (booksmart eh?), I'd say I see 75% (rough guess) of famous producers use a blend of DI & amp'd for bass. I had always used DI before.

Thanks, I didn't know that. I have never been happy with mic'ed bass, maybe there's a trick to it or I just haven't found the right cab/mic combination. For the time I spend setting it all up (which includes helping the bass player get the rig from his car to the studio and back again!), I WANT to believe that it sounds better than the DI or at least that it can help it a little bit, but yet I've never found it does.

 

What would then be my next question is how much of the mic'ed signal do they use in ratio to the DI signal. And do those producer also time-align the two recordings? Maybe that's where I went wrong: I never tried time-aligning the two.

[Eric Wikman]

Again, thanks for your detailed response & time spent.

 

"Disclaimer": I am not good at math.. and science. My strong points have been... groove, harmony... lyrics.. pitch, guitar.... and keys somewhat. And I could go on just using those, but lately I always try to learn other aspects of this biz, to stay inspired and to better my survival chances. Some of these things are also hard for my ears (not an engineer w/ golden ears) to hear a even small differences. Like which bass blend is better. Sometimes it's hard to get big jumps in sound quality after you've been doing this for a while. So I decided to try and improve 25 things in my system by 1 or 2%. This way 25 small improvements add up over time. This is maybe one of those 1%.

 

And this does pertain to using Logics tools.

 

What I am getting at... is when you record the same source w/ more than one mic.. from two different distances, these waves will have phase issues (when combined), and possibly notch filter etc. I'm just explaining my thoughts, and NOT telling you about this. I'm looking for insight to put puzzle pieces together in my brain. Approx 1ms for every 12" of difference.

So you move mics around the room trying to line up the waveforms and get the least amount of problems. Multi Mic'd & distant room mic'd drums come to mind here. And I saw this checked with an expensive box, but that box metering looked a lot like the meter that comes with Logic! Free! So my thinking was.. since the distance can be checked during set-up, why can't the distance between two pre-recorded tracks be checked this way internally also...as well as live? But more importantly... with the free tool that come w/ Logic Pro?

Whew.

[David Nahmani]

Oh ok, you can then use those tools to phase align live... but with a DAW it is so much easier to just visually align the waveforms after the fact.

 

And like I said, since the phase is a function of the frequency, certain pitches will be phase aligned but not time aligned, and what you're really trying to do is to time align them (in which case ALL the pitches will be phase aligned).

[Eric Wikman]

Ok, good to know. I will try some things out.

 

BTW, David, after meeting you in Miami, I wanted to say that you are not only very knowledge-able... but seem to be a very nice person with a great personality.

I think it takes a special type of person to run these forums etc.

Where as I might want to BONK someone over the head after a while. LOL

Like me for asking so many questions.

[nikkik]

re: Bass DI + Bass mic... I ALWAYS try to do this if I can. If it is fretless on a more ambient track, I even like to use a room mic (nice LD). A room mic can be valuable for any bass track, if there is a good room and good placement (the usual things, including decoupling from the room). This, of course, introduces yet MORE possible problems. Using filters and some region nudging can make it magic tho.

 

Getting the bass rig ot sound good in a BIG room is best IMO. Unlike live, where you might be tempted to really slam the low-end, it is totally about balance in the studio. I would take a nice 4x10 or 4x12 cab, toss an SM57, and try it straight on (more high endy type sound), and slowly move to about 45 degrees, find that sweet spot. If you have more mics, or can afford more, grab a D112! Yep, the good old "rock kik" mic that some love to dump in a ported front-head kik setup. Another dynamic that I have had success with is the MD421 (yeah, the classic "tom mic"). Or, grab a nice condenser mic (I choose cardoid pattern) and try that. Back off a good foot or so. Be careful, and a good/high quality tube condenser on a well setup bass and bass amp/cabinet can be completely mind blowing IMO.

 

ALign the signal- lol- easy, or hard. Use your ears. You can double-check your ears if you have the bass player do a little smack. Hot transient, and once the mic + DI is setup, it is a time constant, and all you do is *measure* the distance between that transient peak. Bingo! Delay/latency difference. Align accordingly. Then, I like to sum those, and then mult, and use parallel compression techniques, and/or filtering techniques. Keep it slightly off-center vs the kik, allowing each some breathing room. Walla! Low end slams, bass has defnition and punch. To let those mids "swim" a bit, you can also send (very little, or more if you REALLY wanna get "80's" with it- lol) to a nice stereo chorus type effect. Retain the feld, and send to a sweet verb, and keep this very low and subtle, and pushed to those far edges, and into the back of the mix, and you have the ability to have the bass line "hug" the listener. Experiment!!!

 

Sometimes, the DI signal is all that is needed. But, in this day and age, I have found (for me!) that if overkill does not interfere with the flow of things, it can be a huge boon. One of the worst feelings is tracking a brilliant part, and then realizing in mixdown that, "Oh shiza...a U87 about 14-18" off that 4x10 would have made that Fender Jazz sing in this track." Sad part is, you probably could have set that up in mere minutes.

 

Experiment when you can, but be in control of how much you *should* stray. Catching magic can involve sacrifice...but it does not necessarily HAVE to.

[David Nahmani]

Ok, good to know. I will try some things out.

 

BTW, David, after meeting you in Miami, I wanted to say that you are not only very knowledge-able... but seem to be a very nice person with a great personality.

I think it takes a special type of person to run these forums etc.

Where as I might want to BONK someone over the head after a while. LOL

Like me for asking so many questions.

Thanks a lot for the kind words! And I do bonk people over the head after a while. You have 5 more threads and I'm coming to YOU!