need reassurance with mixer levels....
 

I have read this before so I know it was covered on here but I just want some last minute positive reassurance becasue I think what I read had a descrepancy in it.

I own a Shure FP-24 which is the same as the Sound Devices MixPre unit. My one question is, when I set the 1 Khz Tone generator on I get 0 db on the mixer, should I be setting the XL1s to -12 db (the normal limit on the XL1s) or should I be setting it for 0 db which is all the way at the end of scale on the XL1s? I read on this board that is should be set to 0 db.... this is where I am confused.

I also remember reading somewhere that the scales differ on pro audio equipment from that of DV. 0 db being the optimum average level for pro audio and -12 db being the optimum average level for DV. (my Mackie 1202vlz mixer also uses 0 db as its reference level and -12 db is barely even on the scale way down near the bottom).

If I tune my XL1s to -12 db, the meters seem to match fine though. Also 0 db on the camera is at the point where it is basically clipping audio. I guess what I am trying to ask is, is -12 db on the XL1 equal to 0 db on most all pro audio equipment?

(and yes, I do have the camera set to line level)

I know this has been covered but I am confused as to what I read...

I hope this makes sense and any help clarifying this would be greatly appreciated!

Chris

Assuming that the XL1s audio is like the XL1, 0 dB icorresponds to maximum record level. Anything 'higher' will be clipping. A key indicator is that '0' is the highest level onthe meter. The nominal average record level on the XL1 is about -12 dB on the meter. Many professional audio folks like a bit more head room and may set the average level a bit lower, say -16 or -18 dB, depending on the transients found in the material being recorded.

As a generalization, if you see level on the meter higher than '0' (e.g., +10 and +20 (clip) on the Mackie) you can figure that a level of '0' represents the 'average' level and would nominally correspond to -12 on the XL1 meter.

The AGC on the XL1 will try to keep the average record level around -12 dB. Th AGC is not a bad solution if you do not have the time and free hands to ride levels and do not have a sound person to do it for you.

Note that the line input on the XL1 is designed for -10 dBV and has an impedance of about 10k ohm. Profesional audio gear often uses a line level of +4 dB, substantially higher.

If you are using the MA-100 (and probably the MA-200), keep in mind that it is NOT designed for line level inputs and will start to clip and distort if the signal gets to line level or above. Many mixers allow a mic level output option whihc works well.

Thanks for the reply Don, what I read a few weeks ago (and even copied the text to my computer to reread) really confused me. Maybe it is partly the way I have things set up...

I am using a Shure FP-24 (identical unit to the Sound Devices MixPre) portable field mixer in place of any other XLR adapters. I am not using an ma-100/200 or Beachtek device.

My two XLR mics are running into the FP-24 and I am running a mini-stereo trs 1/8" to L+R RCA cable from the tape-out connector on the FP-24 mixer to the back of the XL1s audio inputs. (exactly what a beachtek or ma-100 would do in theory, correct. balanced --> unbalanced?)

I have the AGC on the XL1s disabled so I can manually set the levels to match that of the FP-24. I also use the limiters on the FP-24 to avoid clipping which is a nice feature. I also find it easier to drop your eyes down to your chest to see the audio levels vs. moving the camera from its shooting position to see the faint little XL1s meters.

I am just wondering now if I am ok using the tape-out of the FP-24 to feed the XL1s?!? it sounds good though!

here are the specs on my portable mixer if it helps any:
http://www.sounddevices.com/products/mx2master.htm


Chris

Using the Tape Out as you described should be fine. Just run some tests to be sure the XL1s level you select work well for you material.

I played around with it quite a bit yesterday and it sounds great! I just didnt know if I was doing a pro-audio "no-no" by using the tape-out to feed my camera.

I will continue to test this setup more though, the FP-24 is great, it is like a beachtek dxa-6 on steroids.

thanks again Don,


Chris

To set my levels, I use the MixPre with 1khz tone at 0db on the MixPre and set my levels on the XL1s at -12db and on the PD150 at -20db (need special padded XLR cables from Sound Device for the PD150). I use the tape out of the MixPre to feed my Nomad Jukebox for excellent results and I use padded XLR's to RCA from the MixPre to the XL1s via the RCA jacks in at line level. I've also used tape out of the MixPre to the XL1s via 1/8" mini to dual RCA's with great results as well. The MixPre is a great little mixer!

thats exactly what I wanted to hear! someone else doing the same thing I am and getting good results, thanks!

Tell me more of the padded 1/8" to dual RCA cable you use to feed the XL1s from the tape-out of the MixPre, I just used a plain old cable I got from Radioshed... should I look for a padded one? I didnt seem to be running hot via the tape-out with the camera was set to "line" in though...

Would it be preferrable to feed the camera from the tape-out on the MixPre or the XLRs??? or does it not matter?

Chris

You are fine using the tape out of the MixPre with the cable you bought. Only if you decide to use the XLR outs of the MixPre, you will need a "padded" cable. My friend is an electronics engineer so he made it for me. I have a dual XLR to RCA cable with a couple of 1k resisters installed to bring the level down a bit to match the output level like the tape out of the MixPre. You should be getting excellent audio with the tape out. I use the tape out as well unless i'm using it to go into the Nomad, then I need to use the XLR outs of the MixPre to feed the XL1s.

perfect!

I know I dont have a trained ear, but the tape-out audio sounds really good to me. I also think I am going to invest in that Denecke AD-20 and run my MixPre XLR's into.

What is the exact level of the MixPre's XLR outs, it seems its pretty hot as everyone has to pad it. It is +4, or higher??? I thought it was suppose to be line (-10) level....

Also, which headphone monitor jack do you use? The one on the camera sounds terrible compared to the one on the MixPre?

Chris,

Remember, the PreMix (and Sony equiv.) are ACTIVE MIXERS -- NOT pads. They have a dynamic range of 110dBu. This means they add gain to the signal level.
The "tape" outputs are set at +11dBu and bal for hiZ;
The "Line" outputs are +22dBu at 100K & +20dBu at 600 ohms;
The Inputs are set at -10dBu.

On the bal question, I set the level on the ref tone at 100 on the mixer and -12 on the camera to GIVE the headroom at the camera signal to avoid clipping at the camera's "0" setting. this way looking at the mixer "0" is a quick ref for approaching max average level (the camera is now at -12dBu) and is time to keep an eye on the level that it does NOT get much higher (you still have the camera now at -12 and still have some room to "0" before it starts clipping (hence the term "headroom". al.

I run the camera headphone out to the tape return of the MixPre, this way I can monitor what is going to the MixPre and what is going to the camera at the tap of the tape return switch on the front of the MixPre. You are absolutely right, the headphone out sounds like complete dog**** from the camera but you should always take a listen to make sure the camera is getting the signal. If you just monitor from the MixPre, you don't really know if your actually getting signal to the camera, that's where the tape return comes in handy.

Thanks both Al & Don, I definately need to read up more on recording. I actually just received a book I ordered from B&N today, On-Location Recording Techniques by Bruce Bartlett. I cant wait to jump into it, it looks like its full of neat info.

Don, great idea with running the headphone out to the MixPre to monitor, never thought of that one and I plan on hooking it up now!

I also wouldnt mind being able to run the camera off of the XLRs if I wanted/needed to but I have no idea where to start looking for padded XLR to rca cables or if I have them made how much padding do I need, 15 db??? Does anyone make these already to go???

Chris

Chris,

I can make up cables for you. If you are using a MixPre (Sound Devices make), you may not need the pad, (I'm not sure aabout the Sony, can check it out though) as the outputs are able to adjust to unbal outs. (I can test this idea first) and the XL1 Sterro 1 & 2 inputs can be adjusted on the camera's menu (padded mic in's are one of the obtions.) I usually get about $40-50.00 per cable (time & mtls project). Let me know. al.

Al, I would be interested in you making a set for me, we can talk more about it via email. My mixer is a Shure FP-24 (not a Sony) and it is made by Sound Devices as you can tell from the following url:

http://www.shure.com/mixers/models/fp24.asp

so the specs will be the same. You can review the downloadable .pdf to
make sure, it has all the specs in it. My email is cferrer@duke.edu

thanks!

Chris

Chris,

O.K sent you an email to the addr. you listed. Will check out the specs at the URL you listed. al