Topic: My first matrix attempt, help please!!

[macacopowa]

HI all, on Friday I will attempt my first matrix. I will record AUD via mikes and R1, and SBD with my iriver. But one question comes to my head, If i record in 24bits the AUD source, after in the post work, I will find problems for to synchronize  a 24bit source with the SBD 16 bits source? It's preferable to record at 16 bits both?

Thanks

[mmmatt]

Depends on the software you are going to use to mix them I guess, but with my multitrack software I can mix 16 bit sources with 24 no problem.  You MUST however record both at the same sample rate or you will have to convert before mixing.

good Luck!

matt

[sleepypedro]

Your problem will come from the fact that each source is using it's own word clock for the A>D. Your going to have what I call "sway". After some period of time you'll fall out of sync. It will become audible and create phase issues.

it's actually called "drift", but... yeah, using disparate clocks is a problem.

[(((KB)))]

Your problem will come from the fact that each source is using it's own word clock for the A>D. Your going to have what I call "sway". After some period of time you'll fall out of sync. It will become audible and create phase issues.

it's actually called "drift", but... yeah, using disparate clocks is a problem.

Because of this I usually just mix the matrix on the fly. In my oppinion, it's easier to do so rather than deal w/ post drift issues. I've probably done 2 dozen or so on the fly and most come out great. The mix % changes from time to time, but mostly I find around 25% SBD and 75% AUD or vice versa sounds decent

. I've been using this mixer for about 5 yrs for on the fly matrix projects. If you don't mind using 1/4" inputs, it's a slam-dunk. It goes for about $80 USD.


http://www.rolls.com/new/mx28.html

Here's a on the fly matrix I did last year w/ this mixer...http://www.archive.org/details/soulive-2005-02-18

FWIW, matrix stuff really isn't that hard to on the fly. Since you have 2 decks, you could  work on the safe side and spilt the AUD feed and run that to one deck and do the matrix to the other.

-K

[batchain]

yeah drift is probably a better term. I agree with everything (((KB))) just posted. Espessially about recording the aud seperate in case the mix doesn't come out well. The BEST this to do is to record with the same clock and seperate channels. This gives you the flexablity in post and eliminates the drift issues. But with your current setup you don't this option. I'd look into what (((KB))) talks about above.

I've heard it brought up that ther could be phase issues with "on the fly" mixes. Anyone know anything about that?

Also, I've done post mixxing before and the time drift issues weren't that big an problem. From the two devices I mixed in the past I just figured in the % difference in the time length of the two recordings and either stretched or compressed the length of one file of the other. With most sound editing programs you can do this without changing the pitch. Then everything mixed fine. An advantage of post mixing is really being able to hear the mix results. It's hard to hear in the club even with good isolating headphones. That being said I've found more often than not that a 60%(mic) and a 40%(board) genrally sounded the best to me.

[(((KB)))]

Yeah, you could have phase issues... technically you're supposed to use a delay on the SBD feed. I don't think it's a big deal to break the rules a little in small venues... and yes,  in my experiences, the closer the AUD mics are to the PA will help reduce the chance of any phase issues. Honestly, I think only once in 2 dozen times I had a phase issue... I think it was because I was running omni's or something?

-K

[BayTaynt3d]

I personally prefer to mix in post anyday. I find that every matrix I do really requires quite a different mix percentage depending on the venue, the music, etc. It's harder to nail that mix on the fly, but at home I can listen to various mix ratios on my headphones, on the stereo, etc., and dial it in just right. Or even better yet, I can use volume envelopes (aka automation) to ride the levels in post if I want -- turning up or down the audience inbetween songs, etc. That let's me have a higher SBD mix during the song, but still bring in a bunch of AUD inbetween, can sound great! Or the other way around, if the AUD is too loud inbetween tracks, you can turn it down for that, but then fade it back up louder during the songs. All a piece of cake in post, but much harder on the fly. But yeah, you have to sync the head, and stretch the drift like said above. The first few times it'll be a PITA, but after a while, it's a no brainer -- I can sync entire shows in 5 minutes or less now in Vegas no problem. The other thing to watch out for is that it is sometimes possible that your AUD might be out of phase with the SBD, if you mix on the fly and have no way of flipping the phase to check that, you'll be shit out of luck, while in post, you can just flip the phase back and forth on one of the sources, and you'll know pretty quick if you are in phase or not. Also, like said above by someone else, if the AUD mics are back far enough from the stage, you'll have a delay to deal with that can ruin the recording if you don't have any way to deal with it. In post, that's a no-brainer to fix too, and you can play with it until it's delayed just right. Anyway, just some food for thought...

[mmmatt]

I've done quite a few live mixes and I've done quite a few post mixes.  I've never used two seperate recording sources though so I can't comment on the timestretch thing.  I find that I get a LOT of pleasure out of nailing it on a live mix.  I do entire festivals that way, and my current rig allows me to do both!  IMO that is the fashizzle... being able to cature individual tracks and a live mix all at once.  Getting the mix right in the field is tough but it is doable.  When I am doing an entire festival I really like to nail the live mix to save myself the post work!  The better the gear you have the easier it is.  More important than the fidelity aspects of the gear is the ability to monitor.  If you mix it live heed this warning... get your settings dialed in on the first song, and after that, live with it unless something changes drastically.  the only thing worse than a poor mix is one that is all over the place.
     Best bet for a live mix is your mics on stage.  Get the FOH to allow you to run your mics on the stage, then you don't have to worry about delay.  If you are setting up in the audience keep your mics within about 25ft of the PA if you can.  If you have to go further back (I've done about 45 ft w/o delay) then you are going to have to lean REAL heavy on the soundboard source.  Doing this will add a bit of "verb" to the sbd source and it can take the staleness out of the board patch.  If the sbd source is severly lacking in some instruments(typical) or is mono (also typical) you will be sorry you did it though.
     Delay is not the same as phase issues.  Phase issues occur when you have your mics pointed a different way than the mics used on stage.  I often times run my mics pointed at the audience from the stage corners.  In this case you have to flip the polarity of the mics 180 degrese.  Polarity and phase are similar things.  If the mixer you use doesn't have a polarity reverse switch, you can build an adapter cable just like a mic cable except you switch pins 2 and 3 on one end of each cable.  I build mine 4" long so that I can just attach them at the mixer but you could actually do it with a full length cable if you wanted to.
    I put together a guide for on site matrix recording and it is attached at the bottom.  It is pretty heavy reading but it is how I do it and I have had lots of sucess... plenty of f-ups too!

Matt

[BayTaynt3d]

    I put together a guide for on site matrix recording and it is attached at the bottom.  It is pretty heavy reading but it is how I do it and I have had lots of sucess... plenty of f-ups too!

Matt

Trust me, READ THIS GUIDE if you are new to matrixes. I felt that it gave me a HUGE jump in the learning curve when I was getting started. I'm probably 20 matrices in at this point (all post-mixed), so I'm pretty comfortable with it now, but that guide was just awesome when starting out -- and not just for the technical stuff, it's got some solid advice for dealing with venues/engineers, etc. too...

[bgalizio]

    I put together a guide for on site matrix recording and it is attached at the bottom.  It is pretty heavy reading but it is how I do it and I have had lots of sucess... plenty of f-ups too!

Matt

Trust me, READ THIS GUIDE if you are new to matrixes. I felt that it gave me a HUGE jump in the learning curve when I was getting started. I'm probably 20 matrices in at this point (all post-mixed), so I'm pretty comfortable with it now, but that guide was just awesome when starting out -- and not just for the technical stuff, it's got some solid advice for dealing with venues/engineers, etc. too...

Seconded. Very nice guide!

[macacopowa]

Thanks to all for your advice. I will read this guide. Surely that solves more doubts than I can  have

[macacopowa]

Finally I made the matrix with two different recorders. Now I am trying to synchronize the two sources, but it's strange because my SBD is delayed versus the AUD, If  I'm not mistaken the AUD it would be the delayed source, no?

[Brian Skalinder]

Finally I made the matrix with two different recorders. Now I am trying to synchronize the two sources, but it's strange because my SBD is delayed versus the AUD, If  I'm not mistaken the AUD it would be the delayed source, no?

All else equal, then yes, the AUD would be delayed.  But if you're using two different recorders, then you're using two different clocks and the SBD clock simply may have been slower.

For post-production mixing of the SBD and AUD sources:  http://taperssection.com/index.php?topic=44072.0

[mmmatt]

Your problem will come from the fact that each source is using it's own word clock for the A>D. Your going to have what I call "sway". After some period of time you'll fall out of sync. It will become audible and create phase issues.

it's actually called "drift", but... yeah, using disparate clocks is a problem.

[macacopowa]

how much ms of delay it's admissible? I'm now working with the idea of no more than 5ms and with a no audible reverb