Ask Rudy
July 18, 2000
Ask Rudy is a column based on questions submitted by users like you. We are currently taking a break from the column, so please hold off on submitting new questions.
Q: Can I use a sub-mixer and still access my effects?
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I just purchased a second mixer to use along side my first. The problem is, I only have two external effects units, and I'd like to be able to use both effects with both mixers. All I've come up with so far is to dedicate one effects unit per mixer, or -- worse -- do without effects on the sub-mixer. Any suggestions, short of buying more effects?
Will Right
Sonning-on-Thames, England
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Hi Will,
Combining two mixers will give you a bunch of extra inputs, which is always a good thing. Even high-end studios will occasionally hook up a sub-mixer to their giant mega-buck console. Sharing effects processors between the master and sub-mixer is a little tricky, but it is indeed possible. Alternately, I'll be happy to sell you some extra effects units I have lying around here.
I'm going to make a few assumptions to get the ball rolling: Both mixers are stereo, we have a handful of extra inputs to spare, and we're using two mono sends -- one feeding each effect. Follow the steps below to route the aux sends from the sub-mixer to the corresponding aux bus of the master mixer.
Here's a hook-up that will let both a main mixer and sub-mixer access the same two effects.
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1] Feed the main outputs of the sub-mixer to inputs 15 and 16 of the master mixer. These channels will handle the dry, unaffected output of the sub-mixer.
2] Connect the aux 1 and aux 2 outs from the sub-mixer to inputs 13 and 14 of the master mixer, respectively. We will use these channels to route signal from the sub mixer's aux sends to the effects connected to the master mixer.
3] On Master mixer channel 13, turn up the aux 1 send.
4] On Master mixer channel 14, turn up the aux 2 send
Now, when you turn up the aux 1 on a channel of the sub-mixer, that signal will flow to input 13 of the master mixer. Aux 2 from the sub mixer will flow to channel 14 on the master mixer.
There is a small catch to this cunning plan: Since some "dry" signal from the sub-mixer will also be passing through inputs 13 and 14 in your master mixer, you may hear some unwanted signal in your final mix. There are a couple of solutions to this, and the illustration below gives you a starting point: By setting aux knobs high and faders low on the "sub-mixer to EFX" channels, this "dry leak" is minimized.
You'll need to follow these important settings on the main mixer in order for the previous example to work as described.
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Better yet, your master mixer may allow you to mute the dry signal without disrupting the flow of signal to the aux buses. If your mixer has "pre-fade" aux sends, the position of the fader will not impact the amount of signal going to the aux bus, so you can actually set channel 13 and 14's faders to zero without messing up your aux send levels. Alternately, if your mixer has assignable buses, you can designate channels 13 and 14 "unassigned." This way, no dry signal coming into these channels will be routed master mixer's main stereo outputs, but the aux sends will still feed the effects.
-- Rudy
Q: Is there some trick to work with timecode frames in Pro Tools 5.0 LE?
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I recently upgraded to a Digi001 system, running Pro Tools 5.0 LE software. On my older Pro Tools system, I could view a ruler with SMPTE timecode. But I can't seem to get this to work with 5.0 LE. What am I missing?
Greg Bosun
Albany, New York
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Hey Greg,
Unfortunately, you haven't overlooked anything. Digidesign decided to remove that particular feature from the "LE" version of Pro Tools -- a very annoying decision. I guess they were trying to give us a reason to buy a $5,000 Pro Tools TDM system instead of a $1,000 Digi001. Grrr!
When I upgraded to PT 5.0 LE software on my Digidesign AudioMedia III card, I immediately missed the ability to "nudge" sounds forward or backward a frame at a time using the numeric keypad's plus and minus keys. I came up with a solution during a bout of caffeine-induced insomnia, but it only works if your session doesn't include a MIDI sequence, as we'll soon see.
Pro Tools 5.0 LE users revolt! You can reclaim some of the missing "frames" feature with a crafty tempo-based grid (see text).
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The workaround involves creating a bar/beat equivalent to the SMPTE frame. Assuming you are using a SMPTE timecode rate of 30 frames-per-second, set your session tempo to 225.23 BPM (under the MIDI menu), keeping the default time signature of 4/4. Next, activate the Bars and Beats time line. Finally, set your nudge increment to 32nd notes.
Now, you can grab a region in a track and use the plus and minus keys to nudge it around by frames. If you've got a QuickTime movie already in your session -- and the movie has a timecode "window burn" -- you'll see the frame counter follow the movement of the region in SMPTE time. By choosing a different nudge increment, you also move regions 2, 4, or 8 frames at a time, as shown below:
| Nudge Value |
Frame Increment
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| 32nd note
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1 frame
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| 16th note
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2 frames
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| 8th note |
4 frames
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| Quarter note |
8 frames |
This little work-around will also re-activate Grid mode functionality, so you can grab, slide, and snap regions to a SMPTE position. Unfortunately, this trick doesn't help you spot a sound to a particular SMPTE frame number. It also means that you can't use the Bars and Beats function for its intended purpose -- setting song tempo in an arrangement that includes MIDI.
Rumor has it, by the way, that Digidesign has heard LE users' complaints and will include the "missing" timecode ruler in an upcoming revision. And not a frame too soon!
-- Rudy
Q: In Which Order Should I Connect My Stomp Boxes?
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I play an acoustic guitar (with a saddle-mounted piezo pickup) onstage, running it through a stomp box graphic EQ and a compressor pedal. Should I put the EQ before or after the compressor?
Jay Rogers
Bakersfield, CA
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Hi Jay,
Good question, because it does make a difference. Start by taking a look at the EQ curve you've dialed in. If you're boosting lows on the graphic, put the EQ after the compressor. If you're cutting lows to tame a boomy-sounding guitar, put the compressor second.
The shape of your EQ curve will help you decide on the best signal flow for your EQ and compressor. If it's set for a bass-boost, put the EQ second.
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If you are cutting bass, put your EQ before the compressor.
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Why the difference? As signal volume increases, a compressor automatically reduces level to compensate. This gives the sound a more consistent overall volume, helping it fit the mix. But there's a catch: Bass frequencies contain greater energy, so they can make your compressor work harder. This can lead to audible artifacts, the oft mentioned "pumping" and "breathing" sound of an over-eager compressor.
Let's listen to a few MP3 examples:
Here's my acoustic guitar's under-saddle pickup without any signal processing.
Acoustic Guitar Dry
It's a pretty bass-heavy sound, which I plan to fix by cutting some lows with EQ. But should we do that before or after we compress the guitar?
Let's find out: Here's the same sound processed through a couple of virtual stomp boxes. This sound was heavily compressed; EQ was later applied to pull out some of the guitar's boomy low end.
Compressor + EQ
Note the "fluttery" sound during some of the sustained chords, especially the first one. The excess bass is freaking the compressor out. Yuck -- this sucks!
Let's try EQ before the compressor. In this example, the same sound was processed with EQ first, cutting excess bottom, then compressed. The exact same signal processing settings were used in examples 2 and 3; only their order was changed.
EQ + Compressor
Note the lack of "flutter" and the overall brighter, livelier sound. This is definitely the way to go for this particular guitar.
If anyone's curious, we can talk about where to put your distortion pedal in the signal path, but that's a question for another day.
-- Rudy
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