Q. What are auxes, sends and returns?

Excuse the simplicity of the question, but I'm always coming across these terms in the magazine, and I don't know what they are: auxes, buses, sends and returns. Can you explain to me what are? Are they all part of the same thing or completely unrelated?

Tony Robbins via email

 
The aux sends on a mixer (whether hardware or software) allow you to send independent mixes to performers on stage or in the studio. You can also use them to feed effects processors at mixdown.

SOS contributor Mike Senior replies: All of these terms are related, in that they are all ways of talking about the routing and processing of audio signals. The word 'bus' is probably the best one to start with, because it's the most general: a bus is the term that describes any kind of audio conduit that allows a selection of different signals to be routed/processed together. You feed the desired signals to the bus, apply processing to the resulting mixed signal (if you want), and then feed the signal on to your choice of destination. If that description seems a bit vague, that's because buses are very general‑purpose.

For example, it's common in mixing situations to hear the term 'mix bus', which is usually applied to the DAW's output channel. In this case, all the sounds in your mix are feeding the bus, and it might then have some compression applied to it before the sound is routed to a master recorder or recorded directly to disk within the software. A 'drums bus', on the other hand, would tend to refer to a mixer channel that collects together all the drum‑mic signals for overall processing, routing them back to the mix bus alongside all the other instruments in the arrangement. Other buses are much simpler, such as those that can be found on a large‑scale recording mixer, feeding the inputs of the multitrack recorder, or those which carry audio to/from external processing equipment. Some don't even provide a level control.

An 'aux' is just a type of bus that you use to create 'auxiliary' mixes alongside that of the main mix bus: each mixer channel will have a level control that sets how much signal is fed to the aux bus in question. What you do with your aux buses is up to you: the most common uses are feeding a cue signal to speakers or headphones, so that performers can hear what they're doing on stage or during recording; and sending signals to effects processors during mixing. In the latter case, the aux bus that feeds the effects processor is usually referred to as a 'send', while the mixer channel that receives the effect processor's output will usually be called the 'return'. For more information, check out Paul White's 'Plug‑in Plumbing' feature back in SOS April 2002; you can find it at /sos/feb02/articles/plugins.asp.

Published September 2011

Q. How much power does my stage system need?

I'm trying to work out how much power a PA system I work with draws, and I also need to come up with a sensible 'plug‑it‑all‑in' type of procedure. (I've read the Sound On Sound December '05 article 'PA Basics'.) It's mainly small venues we play in, such as function rooms and town halls. Looking at the manual for my Mackie SA1530z, I'm kind of baffled. It says:

Line Input Power Europe: 230V, 50Hz

Recommended Amperage Service: 16 amps

Is this saying that a 16‑amp circuit is recommended? The spec sheet doesn't seem to list how much current the box will draw. Also, it's often stated that FOH, mixer and racks, lights and backline should be powered from their own separate sockets (three in total). Is it acceptable to power from both sides of a double socket and another adjacent socket, therefore, all being powered from the same ring main?

Via SOS web site

SOS Technical Editor Hugh Robjohns replies: The 16‑amp thing looks like a generic suggestion to me. In the UK, standard domestic outlets are nominally 13A anyway!

Essentially, what they are saying is that it needs to be plugged into a sensible supply. The typical average current will be a few amps at most, but the initial inrush current on switch‑on will be considerably higher, so don't try to turn everything on in one go!

If you need to know the real current and power‑consumption figures, invest in something like an energy monitor, such as the one I've found here: www.maplin.co.uk/plug-in-mains-power-and-energy-monitor-38343. This one is marketed by Maplin in the UK, but I'm sure you'll find similar devices from all the usual suppliers. You simply plug in the device you want to know about, and the display will give you the current and power being consumed, as well as the supply voltage and frequency. It's a really handy device and I use mine a lot when testing and checking equipment.

Regarding the use of wall sockets, assuming that you're working with a PA and backline system that is consuming less than about 4kW in total (which would be most systems for a modest‑sized venue), use a double socket to run all the audio equipment. That minimises any problems with ground loops.

  
If you need to know how much current your setup is using, a simple energy monitor like this should do the trick: plug in whatever you'd like to measure and its power consumption will be displayed.

Run all the backline from one side of the double outlet, and all the PA (FOH, racks, PA and monitors, for example) from the other side. Supplying the two systems from their own RCDs (Residual Current Devices) is essential too, particularly from the point of view of preventing a backline fault from taking out the PA. If the musicians want to use their own RCDs for their gear, that's fine too!

Running the FOH on a long mains extension from the PA power‑supply socket (or distribution board) continues the theme of 'star grounding' and will minimise the potential for ground loops in the PA system. Run lighting from a different socket (or sockets) and try to keep the dimmer racks and cabling well away from the audio cables.

Published October 2011

KORG Pa1000: more power - new arranger keyboard from KORG

Q. How can I connect hardware synths to my setup?

Currently, I have a MIDI keyboard, a Mackie Spike audio interface, an Apogee Duet interface, a UA Solo 610 preamp and a Neumann TLM103 mic. I use the Spike as a soundcard and run my MIDI through it, and the Duet for recording vocals.

I'm looking to get some hardware synths in the near future and need some advice. In preparation for the synths, I've bought a MOTU Express 128 so that I can have up to eight synths at once hooked up for MIDI. As both the Spike and Duet only have two audio inputs each, I am also looking to do away with those and get a better audio interface. However, if I get rid of them, I do not have a soundcard to produce sound via my monitors.

This is where I'm getting confused. How do I set up, say, three hardware synths via audio and MIDI (I believe you need both connected to get sound in your DAW?) and also get sound from my monitors out of my DAW? Can I get an audio interface that I can record vocals through and plug hardware synths into?

Via SOS web site

SOS Editor In Chief Paul White replies: You have a couple of options, one of which is to use an external analogue mixer to combine the output of your DAW (stereo) with your hardware synths. When the mix is sounding right, you record the output of the mixer back via your audio interface onto a new stereo track, but with the playback fader turned down during recording so the signal doesn't feed back on itself. Speaker and headphone monitoring would be done from the output of the mixer. I used to work in this way and got really good‑sounding results.

The other option is to buy an interface with plenty of spare inputs, ideally one that can be further expanded using an ADAT‑compatible preamp. MOTU's interfaces are generally reliable and straightforward (most include volume controls for your monitors) and I've also used M‑Audio with no problems. Expanders are available from under , such as Behringer's ADA8000, which will give you eight more inputs if you need more. You'd then connect your synths up to pairs of inputs (for stereo) and record their outputs just as you'd record any other audio. Most DAWs now have the ability to set up live inputs in permanent monitor mode, so you can always hear them even when they're not set to Record Ready. Working in this way, each synth would have both a MIDI track to control it and a stereo audio track to record it.

  
Expanding the number of inputs in your setup can be done at a relatively low cost. This Behringer ADA8000 can be found for well under £200$250 and will give you an extra eight inputs to play with.

The advantage of working like this, rather than using an external mixer, is that you can apply plug‑ins to the synth channels if you need more effects. You can also come back to your mixes years later when the synths have been disconnected or sold.

The MOTU multi‑port MIDI interface will enable you to handle up to eight multitimbral synths at once without running out of MIDI channels, so that seems a practical choice.

Published October 2011

KRONOS LS artists first impressions

Q. Should I mix an album as I’m writing it, or all at once?

I'm in the long process of trying to write enough material to put a cohesive, album-length bunch of stuff together. I have a few ideas in 'semi-baked' state, and have got to the point where I have one track written, structured and recorded, and am ready to make a proper mix (I've already made a rough mix).My decision now is whether to go to town on mixing that one track, and then get on with the rest of the writing and recording at a later date, or to keep it at the rough mix stage, finish the rest of the material, then mix the whole lot afterwards.I'm guessing the second approach would lead to greater overall consistency, but this is my first real stab at 'doing an album', if you want to call it that. My output up to now has been rather discontinuous, so it hasn't mattered before.What approach would you take, and how do you think it could help your progress?

Via SOS web site

SOS Reviews Editor Matt Houghton replies: Consistency is great if it's consistently good. Otherwise it's not such a laudable aim! There's no harm in still writing and recording stuff while you're mixing other stuff, but I would rather mix one track at a time, so that any lessons I learn can be applied to the next mix, and so on.
Also, bear in mind that, while mixing the first or second tracks, you might have one of those dawning "Oh, that would have been so much easier if only I'd recorded it like that!” moments, and that would be a bugger if you'd already tracked everything else.
 
There's no particular reason not to continue writing while you're mixing other tracks, but it makes sense to complete a couple of mixes before getting stuck into the rest of a project if you're, say, recording an album. This means that you can apply what you've learnt from your first mix(es) to the rest of the material. It also means that any recording issues you pick up during the mixing stage won't appear in all tracks.

SOS contributor Mike Senior adds: I'd second Matt on that one. It may mean that you end up redoing the first couple of mixes with the benefit of hindsight, but I think, overall, it's probably the best option if you're still feeling your way though a little bit with the mixing side of things.

It's no different from when you're mixing anything: you have to reference your work against any other material you want consistency with. Often that will be commercial releases with which you want your work to compete, but it can just as easily be other mixes you've done, which are destined for the same record. If you make sure to do that, then everything else should sort itself out in the long run.

I do tend to keep the main send effects I used for the first mix available for the second if I'm working on several things for one artist, as long as those effects met with their approval first time round! That does help to give some conformity to the sound. However, there are perfectly valid aesthetic reasons for not wanting to make all the tracks sound the same, so you should still try to make each track shine on its own terms. If that means using completely different mixing strategies, then so be it.

Published November 2011

Dean Forrest and Adjua from “Back Beat Sound System” create with KORG