HomeStudioGuide.com - Guide to Home Studio Recording

I noticed a lot of people asking this question "How do I setup MIDI on my Mac OSX computer (Macbook, Mac Pro, or PowerPC)" so I hope to write a simple and short tutorial for this.

This procedure or steps has been tested on OSX running on PowerPC and Intel chips. It has worked from a simple 2x2 interface to a full-blown 8x8 midi router/merger interface.

1. Connect your midi interface to your Mac computer. Most probably, this will be done via USB. Some models are connected via firewire, but usually, these are combo units. i.e. audio interface and midi interface.

If you need to install drivers for your midi device, go ahead and install it and follow the manufacturer's direction. Depending on the manufacturer, it could be a simple click on a Setup program, or manually copying files to your hard drive.

2. Open up Applications > Utilities




3. Click on Audio Midi Setup.



4. Click on Midi Devices



5. At this point, if the device driver was installed successfully, (and the device is powered on), you will see it represented on your Audio Midi Setup screen.  You can change the icon representation by double-clicking on the device, and selecting a photo from the list of options provided.

Note: If you want "custom" icons for your Audio Midi Setup, I'll show that to you on another lesson.



On the above screenshot, you can see my Edirol 8x8 midi interface, and my MOTU 828mk2 audio/midi interface. For this setup, we'll just the midi ports on the Edirol 8x8 unit.

Click on "Add Device"

How do you hook up or connect a hardware compressor? Compressors are used in SERIES with the signal you want to compress. Other signal processors that need to be connected in series are Limiters and Equalizers.

Option 1:

If you're using a stand-alone preamp, you would connect the compressor after the preamp. So it will be:

PREAMP OUT ----> COMPRESSOR IN
Then COMPRESSOR OUT ----> rest of your signal chain (maybe to a mixer or audio interface).

PROS: If your preamp is balanced, and your compressor also has balanced inputs and outputs, then your whole signal chain will be balanced. 

CONS: You'll need lots of cables. Especially if we're talking about a left and right channel setup or stereo mix compressor.

Option 2:

You can also use a hardware compressor with your mixer. If your mixer have INSERT jacks at the back, you can hook up your compressor via these jacks. This will save you some cabling and make your setup more neater. Cons : You'll have unbalanced connections from the INSERT jacks to the compressor, and from the compressor back to the mixer.

Is this a problem? Maybe not. We're just talking about a short run of a few feet here in a "controlled environment." So running unbalanced may not be an issue.

Below is a picture of the back of the mixer showing the CHANNEL INSERT where you can hookup a hardware compressor, EQ, limiter.



But you'd need a special type of cable.  Basically, you'd need an INSERT CABLE, something like this.




At first glance, the black plug (on the photo above) looks like a stereo jack. Nooooo... it's not a stereo jack. It's called a TRS jack. (TRS stands for TIP-RING-SLEEVE).

An INSERT cable is a special type of cable. Basically, the black TRS plug (from the photo above) is wired like this:



This single jack is carrying both the send signal (that will go to the compressor) and the return signal (from the compressor).

I repeat... it's not a stereo jack. It's not carrying 2 channels. There is no left or right channel here. This is carrying only a single channel.

At the other end of this TRS jack, you'd notice there are (2) TS (TIP-SLEEVE) jacks.  The White TS jack is labeled TIP.  The RED TS jack is labeled RING. 

The TIP TS jack (WHITE jack) goes to the input jacks of your compressor. 

The RING TS jack (RED jack) goes to the output jacks of your compressor.

HINT:  RED jack (think of the letter "R") is the RING jack... which is the RETURN path from the compressor

Make sure you don't swap the RIP and RING jacks when connecting to your compressor. Otherwise, you won't get any signal.

Compressors are one of the commonly used plugins when mixing/mastering. It's not hard to understand how they work... if you know what each button/knob does and how it affects the sound.

When compressors are used properly, the effect shouldn't be noticeable. ONLY when you compare the uncompressed and compressed signal should you notice the difference in the dynamics. Compressors are often used during tracking or mixdown. And during the mastering process, the whole stereo mix may be compressed and/or limited. 

The most common  controls in a compressor are the THRESHOLD, RATIO, ATTACK, RELEASE and MAKEUP-GAIN. Everything else is fluff... like input/output VU meters, or soft-knee/hard-knee, limiting on/off. 

Think of a compressor as an automatic variable volume control. The "volume" control's behavior is set by the attack, release, ratio knobs. This automatic volume control reduces the dynamics of any audio material that goes above the threshold. And this is where the paradox is. If compessors are used to reduce the volume/dynamics of music, how can it make the music sound loud? Well, the answer is in the MAKEUP-GAIN, where the average level of the music can be raised higher without clipping (chances for clipping are reduced because we just reduced the dynamics!).

So let's discuss the important parameters/control in a compressor...

1. THRESHOLD - This is measured in dB. It's a negative value because we're setting levels below the 0dB mark. Threshold (in dB) is that level at which the compressor should start reducing the output level. So if you set the threshold to -37dB (like in the picture above), signals below -37dB in levels remain unaffected.  Signals above -37dB (or in other words, louder than -37dB) will be reduced by the compressor. By how much should it be reduced? That's a function of the RATIO setting.

2. RATIO - So if a signal exceeds the THRESHOLD value, the compressor should start reducing it. Reduction is measured in ratio instead of a fixed numeric value. So let's say you set a RATIO of 2, any signal increase above -37dB in our example above will be reduced by half.  So 6dB above -37dB will be reduced to 3dB. A high ratio will reduce the the levels by a higher amount.

3. ATTACK - So we now understand that input levels above the THRESHOLD value will be reduced. This means, the compressor is always watching the input and detecting it's levels. The question now is, if a signal exceeds the THRESHOLD level, how fast or slow should we take action (of reducing it)?  This is a function of the ATTACK setting, measured in milliseconds. A fast attack (i.e. low millisecond) will mean the compressor will take action faster than a slow attack speed. Therefore, a slow attack (higher millisecond) setting means the signal that peak may be allowed to pass through. What does this mean? It means the dynamics of the signal may be allowed to pass through normally without being compressed... think of a snare hit on a drum. We don't want to kill the initial dynamics of the snare hit. 

4. RELEASE - Now, if a signal exceeds the THRESHOLD level, at some point in time it will go down below  the threshold level again. If a signal goes below the THRESHOLD level, at what point should we stop compressing? Should we do it as soon as it goes below the THRESHOLD, or a few milliseconds afterwards? This is a function of the RELEASE setting, measured in milliseconds.  A longer setting, i.e. a slow release means the compressor is still holding a "grip" on the signal, i.e. still reducing it. A short or fast setting means the compressor will let go of the signal. Long settings (i.e. a slow setting) produces a gradual less noticeable effect in the sound. Short release times are good for percussion instruments, and long settings are good for vocals. 

5. GAIN - This is also known as MAKE-UP GAIN. If you set a low THRESHOLD value, and a high RATIO amount, the overall signal will be reduced.  So we would want to amplify that signal and this is the function of the GAIN setting. It boosts the compressed signal to a sufficient level that we want.

Great, now that we know the different settings. But what can we use compressors for?

Compressors can be used to "even" out the volume by reducing the peaks in the signal (thanks to the RATIO control).  For example, your singer has bad mic technique and their volume varies a lot. We can use compressors to even out the levels so the vocal levels don't vary a lot.

Compressors can be used to avoid overloading/peaking during recording. (Of course, when used during recording, the change is permanent.)

By setting the appropriate ATTACK and RELEASE settings, we can add punch to our drums, adding impact to our beats.

And compressors are also used in mastering (sometimes too much) which adds punch and volume to the track.  But if a compressor is overused, you could also end up with a crunched sound... losing all your dynamics which makes for a "boring" listen. So don't overdo it. Sometimes, slight compression settings is all that is needed.

Sample Procedure for Compressing

1. First, set the bypass switch on the compressor. Listen to your levels... note how loud they are. Take a look at your VU meters and note the peak signal level.

2. Then take off the bypass (i.e. let the compressor affect the signal).

3. Set the ratio knobs... 2:1 or 4:1, depending on how much you want to reduce the levels

4. Set the attack and release time.  Let's use a fast attack time of 5ms and slow release time of 100 or 150ms.

5. Now, set the threshold level until the compressor is showing a gain reduction of 4, 6 or 8dB.

6. Now, use the make-up gain and set it so that we're showing the same peak signal as before compression (see step #1).

At this point, the sound should be punchier. It's like magic... they both have the same peak signal levels but the compressed signal has more weight and feels more solid.

If the sound is too compressed, and all the dynamics of the signal seemed lost, raise the threshold level (which means you have to lower the makeup gain), or increase the attack time (i.e. make it slower to react). 

The Bypass button is your best friend. Sometimes, subltle compression is all you need so make sure to hit the bypass on/off button often to hear the difference between no-compression and compression.

If you're using compression for the final mix on a stereo track, you may want to combine the compressed and non compressed signal.  This will make the music "thick" while still retaining the dynamics of the original music.


Typical Compression Settings

These are just typical settings, and don't make this the "rule." The exact setting will depend on the material you're compressing and the effect you want to achieve.

Delicate Vocals - We want to set the RATIO to a high value and high TRESHOLD. By using these settings, the softer vocal sections will remain uncompressed and only loud, ear shattering vocals will be compressed.

Threshold - set the threshold (i.e. lower it) so that the loudest vocal section is reduced by 6dB.
Ratio - Set to 6:1 reduction

Make sure threshold setting is not too extreme. We only want the loud vocal sections to be compressed by 6dB and quiet vocals remain uncompressed.

Pop Vocals/Commercials (yes, those annoying TV and radio commercials) - Okay, we want obvious compression here. So we want compression always going on for almost the entire material, and a very big reduction during loud masterial.

Threshold - set the treshold so the the softest vocal section is reduced a little bit. (-1dB or -2dB)
Ratio - Set to 2:1 reduction
Attack - set to fast setting
Release - set to a little bit slow
Make-up gain - increase gain to increase volume again.

At these settings, we're raising the average level of the whole material... i.e. making everything sound loud!

Drums - or any percussive instrument. We want a punchy, thick sound in the mix.

Threshold - set threshold so all drum materials are compressed by -3dB.
Ratio - Set to 4:1
If you have a hard/soft knee switch, switch to "soft knee"
Attack - set to a fast setting
Release - set to a mid setting

By lowering the threshold setting, you can make the drums more compressed. But be careful not to overcompress it too much or you'll lose the dynamics and punch.

Bass guitar/bassy synths - we want a fairly constant level for the bass material so we have a "thick" sound in the mix.  We don't want bass volume going loud and soft, we want it consistent.

Threshold - set so that only loud bass material (i.e. the peaks) are compressed.
Ratio - Set to 4:1
Attack - set to slow/mid
Release - set to slow/mid

Electric lead/rythm guitar - we want compression on these material. We want the guitars to be punchy and level out the volume.

Threshold - set to a low setting, to achieve constant compression
Ratio - Set to 6:!
Attack/Release - play with it

Looking to save some money? Create your own cables! By spending a few dollars on jacks, shielded cables, solder and soldering iron, you can save a ton of money in cables.

It's easy. Here are some step by step photos. 

At the bottom of this article, is a wiring guide for XLR to XLR, XLR to TRS, XLR to TS, and whatever combination you can think of.

On this guide, I'm wiring up an XLR cable.  First, we disassemble the cable by unscrewing the lock screw. Pull out the rubber plug (black thingy) and then you'll be able to push out the 3-pin connection assembly.

DYNAMIC RANGE

The simplest explanation of Dynamic range is the difference between the loudest and quietest parts of the music, as measured in decibels, is called the Dynamic Range.

If you need a review of what is a decibel, click here.

However, there is a dilemma here. How do you define what is the quietest part of the music? It seems an easy definition, but if you consider that electronic audio equipment have inherent self noise, then the quietest part of the music is fainter than the self noise produced by the equipment. i.e. the quietest part of the music is below the "noise floor" of the equipment.

So in this case, the dynamic range is the difference between the loudest part and the noise floor, in decibels.

Are you still confused? okay.... let's say you're attending a symphony concert. Sometimes, the orchestra will be playing full blast! Let's consider this the "loudest part of the music."  Then in one part of the music, only the flutes can be heard... let's call this the "quietest part of the music."  The difference in volume between the solo flute and the whole orchestra playing is the "dynamic range" of the orchestra.  But by some bad luck, you're seated to an obnoxious person that's talking on his cell phone.  You can't hear the flute solo clearly because your seatmate is making so much "noise."  That obnoxious guy, is your "noise floor."  So that means, the dynamic range of your music has been reduced. Because now, all you can hear is anywhere between the loudest part of the orchestra playing and the noisy guy talking on his cell phone.

The above illustration illustrates how "noise floor" can rob you of available dynamic range. 

In real world scenario, we'd want equipment that gives us the lowest noise floor possible. Because this makes the dynamic range available to us bigger.

For all you Cubase fans out there... here are some video tutorials to help you make the most use of the software.

#1 Audio Midi Setup in Cubase

#2 New Project