Recording Tips: Limiters

If you have spent any amount of time recording and mixing, you have likely tried to keep a sound from clipping or tried to boost the overall volume of a recorded sound only to have it clip because of a small section or a single sound that tends to be much louder. We’ve already covered two types of compression, basic and side-chain, now I’d like to discuss limiters, which will help with the above issues.

A limiter is a compressor that is typically set to a higher ratio and faster attack (see compressor basics). The goal of a limiter is to “limit” a sound to a specific top volume. Limiting effectively reduces the dynamic range of a sound, this means that if set correctly, it will turn down the louder sections to bring their volume closer to the softer sections. Limiters are used frequently in live sound applications to prevent sounds that are too loud from damaging speakers. In a studio setting limiters are often used as a tool to reduce louder sounds so that the volume of the track as a whole can be increased without clipping or distorting. We will focus here on the studio usage only.

A compressor begins limiting once the ratio is set above 5:1 although it is usually a higher ratio setting, closer to 10:1. Also, attack times are generally much faster. To set up a limiter, start by setting your threshold (or ceiling) to the dB level that you want the sound to start to being effected. An example of this would be if you had a sound recorded where the majority of the sound was below -10 dB, with some areas that were around -2 dB and you wanted the volumes of those sections to be closer to the rest of the mix, you would set your threshold somewhere below -2 dB, but probably not more than -10 dB. Next, adjust your ratio to the desired amount of effect you want to use; 10:1 is a good starting point. Now you will use a fairly quick attack setting (this will be a “to taste” adjustment) to tell the limiter how quickly you want the effect to be executed on the sound. Finally, you can use a make-up gain to increase the overall sound of the newly limited track, which should provide for an overall higher volume without clipping. If you limit too much and use an attack time that is too fast, the result will likely be undesirable.

Limiting is a great way to protect speakers, smooth out performances and increase volume. Remember there is no standard setting for any two sounds, so spend some time tweaking the parameters to get the best effect possible. Try not to use more limiting than is necessary as the goal is to improve the overall mix without being overly obvious. The untrained ear should have no idea that it is there at all (unless that’s desired goal).

Recording Tips: Acoustic Guitar Microphone Tecniques

Right behind voice, acoustic guitar is one of my favorite sounds to record. The sound can be extremely complex and is governed by so many factors that it is actually very easy to experiment with. In sticking with the basics, this installment will focus on micing up an acoustic guitar. I will share with you my favorite techniques and give you some general “rules of thumb”.

Before we get into micing up the guitar, I want to share and stress a lesson that I have learned many times over. The overused saying, “fix it in the mix” should be thrown out the window and replaced with another often-used saying, “garbage in, garbage out”. The goal should always be to capture whatever sound you are recording in the best possible way. When looking at recording acoustic guitar, consider the variables that can be optimized prior to setting any levels. To many of you, this will seem like common sense, but I cannot tell you the number of times that I have had to “gently suggest” this to musicians. First, replace the old strings on the guitar with new ones. New strings will drastically change the tonality of the sound. Next, please make sure the instrument is tuned. Finally, have extra strings, picks and anything else that is unique for the instrument handy. Nothing kills the energy of a session faster than having to run up the road to the store to buy a new set of strings because one broke on the perfect take.

Now that you’re ready to play, let’s mic the guitar. Condenser mics are usually the best choice for acoustic guitars due to their ability to capture the higher frequencies. I usually favor a large diaphragm condenser if I’m only going to use one (which I almost never do). If I were to do what most people new to recording would do, which is to place a single microphone facing directly at the sound hole, I would find out that the sound would be very resonant and bass heavy. This sound is probably not the sound that you are going for. This sound is often more desirable, however if you are using multiple microphones to capture the entire sound of the guitar. So in a single microphone set-up, you will want to place the microphone between the sound hole and the 12^th fret facing the guitar. Sometimes, when using only one microphone, I will place the microphone approximately at the 10^th fret facing back toward the sound hole. This gives a good mix of body from the sound hole and brightness from the neck.

More typically, I’ll use three mics for acoustic guitars for the reason that the instrument will sound very different depending on where the mics are positioned. I still begin with a large diaphragm condenser microphone, but this time I place it directly in front of the sound hole approximately 10 inches away from the guitar. This microphone will serve as the device to capture all of the body and resonance of the guitar. Next, I will set up a small diaphragm condenser at roughly the 10^th fret to capture the brightness and higher frequencies that the instrument is producing. Finally, I will put a third condenser microphone over the player’s right shoulder (if they are right handed, left if they are a lefty), to capture the sound that they are hearing. This microphone to me is the most important because you are hearing the performance the same way the guitarist is and it captures a much more “true-to-life” guitar sound. I will interchange large and small diaphragm mics depending on the performance style. By using three separate microphones to capture the performance, you will then be able to blend them together to get a very clear and accurate sound when mixing.

One word of caution regarding the multiple microphone technique; you will encounter phase cancellation if your microphones are not placed very close to the same position and there is a delay time between the microphones. As long as you are using 3 separate tracks, you can adjust to this while mixing, but as a best practice, try to keep the mics to a very similar proximity to the guitar.

The final mic technique for acoustic guitars that I will share with you is XY pattern micing. I use two small diaphragm condenser microphones with the capsules one on top of the others and one pointing toward the sound hold and the other toward the neck of the guitar. I generally place these microphones 6-10 inches from the guitar with the mics positioned right between the neck and sound hole. I pan them hard left and hard right and record. This creates a very nice and ear pleasing stereo effect blending the dark sound from the hole and the bright sound from the neck.

There are, of course, numerous ways to mic acoustic guitars, these are just a few. The best thing to do is move the mics around until you like what you hear. Try adjusting the height and angle of the mics as well as moving them up and down the guitar. Remember, recording is very subjective, find what sounds best to your ears and record it!

Recording Tips: Preamps

Which preamps are best is one of the most debated subjects in the pro audio world. Preamps are extremely subjective and one of my top three most important things for good recordings. It’s not surprising that this is a confusing subject for many people entering the recording community; there is simply no clear-cut answer on what exactly is needed. In keeping with sticking to the basics as I have done in my last several discussions, I hope to clarify this topic for you all to some degree. I will be focusing on preamps in a general term and will not be getting into the tube vs. solid-state debate right now. We’ll save that for another day.

Preamps are very simple actually, their function in your recording process is to take a low audio signal and amplify it so you can capture the recording. In it’s most basic form there is an input for you to plug your microphone into and an output to plug in to your recording interface. You will have a gain knob to adjust how much the signal is amplified, a phantom power button to power condenser microphones (+48) and typically (although not always) and input impedance to help color the sound depending on the source. Sounds pretty simple right? Well, in a perfect world, yes, but the preamp has to boost this signal without adding too much noise to your recording. A mark of a good preamp is being able to increase the gain with very little noise. Many less expensive and poorly designed preamps will create buzz and hiss as their volume is increased, thus adding unwanted noise to your recordings.

So how do you choose one? Well, as I mentioned earlier, it is subjective and if you are just starting out, your choice will probably be governed by your budget. Good preamps can be very expensive; many go for as much as 3-5K. Many mixers and DAWs have them built in and you will likely find that there is a considerable amount of noise created when the built in preamps are used (not always the case, but more times than not). If you are not looking to spend much money, say less than $400, I’d suggest saving for a little while until you can afford a decent model. There are some very acceptable single-channel preamps currently on the market in the $500-1000 price range. Waiting and getting a quality preamp will make a very noticeable difference in your recorded sound. Noticeable to the point that it will likely expose problems you did not even realize that you had. Usually problems that were concealed by the noise floor that your ears were used to.

You do need to know that if you purchase a great preamp, it might not be the silver bullet that makes all of your recordings masterpieces. There are many things in the signal chain that can affect the sound and the preamp is only as good as the other devices in your signal flow. Considerations are your microphone, A/D (Analog to Digital) converters, recording environment and really just about anything that the signal flows through prior to being captured. Think of recording as if your are building a road for sound to travel on as it is heading toward it’s final destination, in most cases today, your computer. The longer you make the road and the more circuitry that the sound has to travel through the bumpier the road will be and higher the probability of creating unwanted noise. Keep it simple, find what works and sounds good and don’t try to take too many shortcuts, especially when it comes to the preamp.

Recording Tips: The (Very) Basics

We all start somewhere in our quest to set-up our perfect recording environment and we really never stop trying to improve upon it. After getting my degree in audio engineering/sound recording technology and leaving the excellent recording facility that I had been so fortunate to have access to, I found myself yearning for a space of my own. Like most college graduates, I was high on enthusiasm but low on cash. I was given a Tascam 4 track cassette recorder for Christmas by my mother and spent what little cash I had on a cheap dynamic mic. I had a host of songs ready to record, something to record them on and a lot of time on my hands. I went to work recording, but was not so pleased with the results. I kept tweaking my system, borrowing equipment and working on my space until I found what worked for me. I spent the next few years building up equipment, doing freelance projects and honing my skills and in 2004 I was given the opportunity to build and run a small studio for a local company. While running that studio, I continued to build my own until 2006 when it was ready for the world. For those of you just getting started on you quest of putting together your studio, I want to share some of my thoughts and hopefully help you avoid some of my errors.

A good friend of mine and very talented engineer gave me the best advice I received about two years into my project. By this point, I had a little bit more money and was shopping for gear; he told me to focus on the three most important elements first. They were, the microphone, the preamp and the room. He said if you got those three things right, you would be making good recordings. He was absolutely right, the first two were the easiest for me. I had heard my voice through many mics and had a good idea of what it sounded best through, while I couldn't get the mic I wanted at the time (AKG C-414), I was able to find a good deal on an Audio Technica 4040. I found a good price on a decent pre amp and was already extremely pleased with my results. The room proved to be the hardest of the three for me. It seemed that no matter what I did I would still end up with things in my recordings I didn't want; too much room noise, frequency issues and the occasional dog bark. I lucked into some Sonex acoustic foam from a recording studio that was renovating (can't beat "right place, right time") and went to work covering the room floor to ceiling with the foam. This worked well for evening out the reflections and I was able to work my schedule around the dog so my recordings were well on their way. I need to mention that what I didn't buy at the time was a recording interface or anything to process or effect sound. Taking care of these critical components, for me, did much more than any of those could have.

My second realization came to me when I purchased a load of equipment from someone else's failed studio venture. That realization was that you have to know the scope of your recordings and how your equipment works together. If you have a Neumann U87, you are recording it through a cheap preamp and have bad converters, you don't get all of the benefit from the U87. Furthermore, you don't need to spend a lot of money on studio gear that you don't have room to use or won't use for your primary reasons for putting together your studio. After buying this lot of gear and seeing a good portion of it sitting unused, I realized (as I'm sure the person I purchased it from did as well), that I didn't need it and while it was a good deal, I wasted a lot of cash.

Finally, once I got a clear scope of what I was primarily recording and covered my previously mentioned critical components. I started to see that my more narrow focus was yielding much higher quality recordings. This allowed me to spend less time clearing trash from my recordings and trying to make them sound like they were recorded on decent gear and more time on perfecting a well recorded sound. From there, I continued a focused path and honed my craft accordingly, all the while the other stuff that I had been trying to force prior to that began to happen on it's own.

I'll leave you with, what I believe is a great place to begin assuming you have something to record sound to:

Know what you are going to be recording - Start small, it's good to dream, but be realistic. If you are a voice actor wanting to record your voice, you don't need to buy a set-up to record a full band.

Network - Find people that are making good recordings and see what they are doing that you can adopt. You will pick up a lot of tips and tricks and people love to talk about their craft.

Get a good mic - Try several out and see where you voice naturally sounds the best. You don't have to break the bank at first, but find something that can last you a little while and learn to use it well. Also, invest in a good pop filter, this will save you a lot of time editing.

Get a decent preamp - Talk to others in your field and sales people to find out what others like you are purchasing.

Develop a recording space - This should be no smaller than a 5x7 area that is treated to reduce reflections. Any smaller than that will produce frequency issues that are a pain to work with. There are some pretty cool free services available now that were not there for me. For instance, Aurelex will provide you will a free room analysis and treatment recommendations. You can do this through Sweetwater sound.

Finally, don't underestimate yourself, I have heard some downright incredible recordings come out of a bedroom. It's not the ingredients, it's the cook. Spend the time and money on the right tasks and equipment and get good using what you have. If you do this, your studio will grow before you eyes.

Recording Tips: Side Chain Compression

Now that we have covered the basics on both the compressor and the EQ, we can now start discussing a few of the cool ways to use these tools to improve our recordings. For this discussion, I’ll be discussing a very useful compressor function for those working with voice; Side chain compression.

Side chain compression is feeding one audio source into the compressor to trigger the compression of another audio source. While this can be used in many different ways, I will only focus on its basic use for voice. The side chain compressor is most frequently used for “ducking” or turning down a sound to get out of the way of another sound. You might use this if you are mixing a music bed underneath a voice over track. If set up to do so, this will allow the music to be automatically turned down when the voice track is running and swell back up once the track is silent. Some compressors have this built in and can simply be switched to side chain mode, but it is more likely that you will have to seek one of these out. If you do not have one, there are some good free or very cheap ones that can be downloaded with very little searching. Please realize that every compressor is a little different in its functionality, in this example I’m using a basic Digirack Compressor/Limiter. I will explain how to use a side chain compressor to “duck” a music bed under a voiceover track. Here are the basics:

First you will need to route your “Key Input signal” (the signal you want to be used to trigger the compressor), in this case your voice track, through a bus. Next, place the compressor on the music track to be “ducked” and set the compressor to side chain mode (also sometimes called key input mode). On the Digirack compressor clicking the button that has a key on it does this. Next you will need to let the compressor know what signal it is looking for to be triggered. Look for something that is labeled “key input signal” or similar. This will need to be set to the bus you assigned to your voice track. At this point all of the signal routing is complete and all that is needed is to tweak the settings to “duck” the music track based on the voice track. These settings will be very different depending on the tracks that you are using but I will typically use a fairly slow attack (100-150 ms) and very slow release or decay (600 ms – 1 s) to make this effect as unapparent as possible. I also use a fairly high ratio (6:1 or higher) to limit the music track when the voice track is playing and adjust the knee of the compressor (usually soft) to make the volume transitions as seamless as possible. Also, you will not need any gain compensation for this. The threshold will be dependent on the level of your recorded audio, but all of these parameters can be tweaked until it sounds right to your ears. Find what feels right to you and go with it.

Using a side chain compressor can save you a lot of time when mixing voice over on top of music and will certainly prevent the music from overpowering the voice. It can feel very confusing at first, but once you get it, my bet is you will find yourself using it on just about any project that has these two components.

Recording Tips: EQ

Continuing on through some basic recording techniques, this installment will focus on some basic equalizer (EQ) functions and how you can use this tool to enhance your recordings. As with the previous discussion on compressors I will focus primarily on the use of EQ for voice and discuss only very general aspects of usage. In it’s basic forms, the EQ has two different styles, graphic and parametric. The graphic EQ is the most basic and where this particular discussion with focus.

The audio that we record is comprised of many different frequencies coming through at different volumes. Equalization allows us to boost (turn up) or cut (turn down) those frequencies individually. Equalization done correctly can enhance your audio by giving it body (low end), warmth (mid range) and brightness (high end). Equalization can also correct minor recording issues such as plosives (sounds generated by bursts of air such as the “P” sound) and sibilance (hissing sounds such as the “S” sound). The EQ will not make the voice sound like someone else’s, but will enhance (good or bad) what is already there. To use a cooking analogy, the EQ is like salt; it can make good food taste great, but if you use too much of it, it will ruin it entirely.

Typically with a graphic EQ there are adjustable parameters for individual frequencies. Each one can be turned up or down to affect the audio. There is typically also a Q control, which determines how narrow or wide frequencies around the selected frequency will be affected. Think of the Q control as a gentle “U” shape with the affected frequency in the middle, the higher the Q control is set the narrower the “U” is, thus affecting fewer frequencies.

In most cases, the goal of the EQ is to be undetected by the listener, therefore cuts are much more friendly in facilitating this. Boosts can very quickly cause a voice to sound unnatural so boosting gently is preferred. You can take a little more liberty with the cuts without creating a too unnatural sound. Below are some general tips for voice equalization:

• Use of a High Pass Filter (HPF) reduces frequencies below the set frequency (this is sometimes called a shelf). This is very handy for use in vocals as most audible speech is below 125 Hz and applying an HPF somewhere below that can instantly remove plosives and rumble created from mic stand movement.
• Use a slightly lower Q setting (around 1.0) for a gentler, less apparent affect.
• Frequencies between 125 Hz – 1 kHz make up the bulk of the human voice; lower frequencies will affect the body of the sound, adding or subtracting richness while the higher frequencies will affect nasal qualities. Frequencies above 1.25 - 5 kHz affect the crispness of a vocal and allow it to cut through other sounds better such as a music bed. Frequencies above 5 kHz affect the brightness quality of a voice sometimes providing a more breathy sound. Too much boost in the higher frequencies will cause the voice to sound thin and brittle.

Not one recording is the same as the next, take time to work with each individual recording and address the uniqueness of the sounds. The EQ is a very easy to use tool and can have a very positive impact on your finished product if used wisely.