Understanding Signal Flow in the Recording Studio

 

Signal Flow is almost like a map of the sound traveling through the setup almost like a river or pipe flowing.

Signal flow is the term we use to describe how the sound flows through the chain of devices.

Signal flow is all the gear and cords and wires and other electrical components used for recording or live sound in a audio technology setup.

The path the audio takes.

 

 

 

What is Signal Flow in terms of audio in the recording studio

Signal flow is the path that audio takes from the microphone through the cables and electronics to eventually come out of the speakers and or headphones. Understanding the signal flow of the studio will help you set up your recording perfectly, as well as trace potential issues. Each studio will probably be slightly different, but many of the same concepts are usually found throughout all setups. Signal flow can be in the analog as well as digital realm, inside the DAW or running through wires and analogue equipment in the studio. Even if you’re using a mostly digital setup, you are using a microphone and analog preamp at the very beginning of you’re signal flow.

 

 

A Basic Example of Signal Flow

Here is an example of signal flow in a basic recording or live sound setup.

 

Voice or Instrument into > Microphone > Mic Cable > Recording Snake (Ch 1) > Audio Mixer> Audio Mixer Preamp > Audio Mixer EQ > Audio Mixer Fader > Master Output of Mixer > Speakers with sound Coming Out!

 

So Signal would travel down the mic cable into the snake into the mixer through the channel with EQ and Fader, into the Master Output of the Mixer which is plugged into the speaker, which plays the sound in the microphone. This flow of signal down the chain, and understanding how it could be interrupted or affected at every stage can help you set up your audio equipment properly and and figure out possible issues.

 

So for example, Maybe you have no sound coming out of the microphone oh no. Don’t panic.  Start tracing signal down the chain. First, is it plugged in. Yes? Is the snake channel you are plugged into plugged into the mixer. Is the channel on the mixer getting signal. Is the preamp adjusted properly  Is the fader up. Is the channel assigned to Left Right Master output. Is the master output fader Up. Are the speakers plugged in and powered on. Is the microphone broken? Could there be a bad cable?

 

Understanding signal flow will help you trace audio signal problems, as well as make adjustments to the sound appropriately.

 

Understanding Pre Fader Post Fader

There is a lot of Pre Fader Post Fader on Audio mixers. That is because for different applications you may want to send the signal PRE FADER or BEFORE the fader or After or POST fader. So when the fader is down in a pre fader situation, the signal is still present because the signal is sent PRE fader. In a post fader situation, the signal is sent AFTER the fader, so any fader action will still affect the signal being sent.

 

More Advanced Signal Flow

Signal Flow can get Very Complicated. Many channels means many more routing options.

Here Is an Example of What Signal Flow would look like for a very basic typical Full Band setup

 

First we will go through the Channels

Channel 1 Kick Drum

Channel 2 Snare Drum

Channel 3 High Hat

Channel 4 Rack Tom

Channel 5 Floor Tom

Channel 6 Over Head Left

Channel 7 Overhead Right

Channel 8 Bass

Channel 9 Guitar

Channel 10 Singer

Channel 11 Keyboard Left

Channel 12 Keyboard Right

 

These microphones are plugged into the stage XLR snake box with XLR cables.

The 12 XLR Snake Channels are Plugged into the Back of the Mixer Microphone Inputs

Each of these 12 Channels has a Mic Preamp usually at the top, after that an insert point. The insert is for a compressor, so Kick, Snare, and Bass each go to a compressor after the mic preamp, then back into the EQ. the EQ and Insert both have a bypass button on the channel. After the EQ flowing downward is the PAN and Group Bussing. Pan goes Left Right and Bussing assigns the channel output to Groups 1-8 or Master LR Output.

Each of the Drums is sent to Group 1 Drum Group. Drum group has another special compressor on the Group Insert. Bass is assigned to LR along with guitar and singer to go to stereo Output. And keyboards and Over heads are panned, and sent to Groups 2 and 3  To be controlled with 1 fader to make it easier.  Each of the instruments is EQ’ed to Taste and the compressor is set to appropriately affect the signal. Microphone preamps are set to appropriate level.

Direct Outs

Direct Outputs or Recording Outputs can be coming from different places. Are the direct outputs before the fader or after the fader? You will want to know if you are making a recording. Many times direct outs are after the EQ but Before the fader. There are typically many switches to control the behavior.

 

Auxes are Auxiliary Outputs

Auxes are like groups, but usually used more as sends for signal. The signal could be sent to effects units, or the signal could be sent to stage monitors or headphones, in ear monitors or other outputs.

An example would be:

Aux 1 is pre fader and goes to Stage mix Left Guitarist

Aux 2 is pre fader and Goes to in Ear monitor singer center

Aux 3 is pre fader and Goes to stage wedges for bassist on Right

Aux 4 is pre fader and goes to drummers mix

Aux 5 is post fader send for reverb

Aux 6 is post fader send for delay effects

A button on the mixer is pressed to make Aux 7 control direct output. pre fader.

 

also there are Inserts on the stereo output with a limiter and compressor and eq on the left right master output.

 

Many Analog or Digital Setups will Follow something similar, its just a matter of how many inputs and outputs and what goes where.

 

More Complicated Signal Flow Setups

Well Golly…. This just couldn’t get any more Complicated. Well it can and does.

One way is Dynamics and EQ. You can have Filters and side chaining. On SSL G series there are options to use the filters in side chain mode or to use dynamics in the fader output path or in the input path before EQ.

Another way is patch bays. Patch bays can have points within the signal flow chain to patch in and out of. So for example. Studio A has a huge console and patch bay. Channel 13-48 are the snake channels for the recording room we are using for keyboards. We have Left and Right plugged into 1 and 2 in that room, which go into channels 13/14 in the patch bay, which get plugged out of the studio XLR outputs into the channel input on channel 11-12 of the console.

 

Full normal Half Normal Patch Bay Nonsense

Is the patch bay half normaled full normaled? This is a question you may have and befuddling everyone. What does that mean? A fully normaled studio patch bay will break the connection when you plug a wire into it.

So in our example, plugging the patch cord in to the Channel 13 patch point breaks the connection so when we connect it to channel 11, the signal is re-routed completely.

 

So whats a Half Normaled Patchbay Channel?

Half normaled means the signal is split. So In the example case, if channel 13 is patched to 11 and patch bay is half normaled, the signal will be split and show up at BOTH places. Useful in some applications, but you want to know that.

Whats the idea behind it? You have some normalization that has the signal input normaled to the output. So Fully normaled Channel 13 is normaled to its output on patch bay channel 32 so the NORMAL setting is there, so when the studio resets, It has a a NORMAL setting. Signal is Normaled from Input to Output.

 

Even More Signal Flow: Regarding Higher End Stuff

Every stage of your signal flow chain affects the signal. For example. a very nice guitar setup sounds a lot better than a cheap one. A microphone can cost hundreds or thousands. A mic cable is less important, but you want at least a somewhat good quality to ensure the signal is not lost due to thin wire or maybe a poor quality end connector or damaged condition. Signal flow gets more complicated and expensive when you are talking about thousands in equipment, and higher end compressors and outboard EQ, or fancy consoles with many features, many channels, and rack mount effects and outboard preamps. You can spend thousands on 1 channel and then have 24 , 48 or more channels. Wow. So what do you NEED. What do you WANT and what will make the most difference. Everyone is going to use the best equipment they can get their hands on, but understanding it and using it in the most creative and musical way is what really matters.

 

Can you Get Good results with simple Signal Flow? Of course!

There is no real reason why a microphone just plugged in cant sound good without complicated signal flow. Maybe the keyboard player is just perfect. They know to adjust their own volume, each patch is properly balanced. There is no reason to be using a compressor and all kinds of weird effects when maybe just a simple approach of letting them do their thing is best.

Not every audio signal needs EQ adjusted. While it is tempting to adjust EQ and compression on everything, sometimes you adjust and then find later the natural sound is best, so don’t be afraid to leave it be, or the handy audio engineer catchphrase. If it sounds good… it IS good. 

Signal Flow gives you the power to make adjustments where ever you need. You can still use the flat EQ, and the regular settings, and get great results even with simple signal flow. You don’t NEED a patch bay or fancy setup to get really good results. A simple minimalist  approach can still be high quality.

 

Get Good results Going IN

Crap Goes in. Crap comes out. Another catch phrase of audio engineers. You need to get the best performance and sound going in to make the best sound.

 

A lot of times its like “oh jeez the bass is too tinny sounding better EQ the High end”. Better get busy on the mixer EQing the bass, …but you should be Asking yourself ….why does it sound like that? Bass Player: ” Oh well i always turn the high presence up to 10 to hear it. but it doesn’t really make any difference. OK. MYSTERY SOLVED. The sound mixer and everyone in the band votes you turn down the treble a little so we can hear our own stuff. ok great! fixed! Many times the best solution is to solve the problem at the source. Use a different mic. change how the drums are tuned or adjust vocal techniques to up your game. True professionals adapt and overcome. We solve problems together. Many times solving the root issue creates even more powerful results down the line. For example now that the guitar tone is cleared up we can finally hear the vocals! or now the drummer understands hitting the cymbals too hard and the drums too SOFT is creating issues for everyone on stage, now the overall the drum sound is better and the band sounds better as a whole. It all works together.

 

Thanks for reading I hope you found the information you were looking for.