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**thismercifulfate** · 06-24-2011, 11:16 AM

Condenser Microphones

Condenser mics are very much at home in a studio environment. This is because they are better suited for critical recording situations, where the goal is to capture an accurate or realistic sound, due to their full frequency responses and transient accuracy. But they're fragile instruments and must be treated with care. With improper handling, they can be rendered useless. They require phantom power to run. Phantom power is power that is provided to a microphone (or pickup) through a microphone cable from it's mixer or preamp. Some mics, like the RODE NT3 have a battery compartment, which can power the mic via a switch. Today most condenser mics need 48v, but some mics are designed to work with power between 12 and 52v. This helps them adapt to things like strange sound boards and also very long cable runs.

Whereas dynamic mics work using electromagnetic induction, condenser mics use electrostatics. At the heart of every condenser mic is a capacitator. The capacitator has two plates; one fixed, the other movable. The movable plate is a diaphragm, typically made of a several microns (1 micron = one 1000th of a mm) thin mylar (the same stuff drum heads are made out of) and is sputtered with gold. Since nothing is attached to this diaphragm, it reacts very quickly to fast transients. Each plate is connnected to a constant power source, so when powered with phantom power, this capsule has a constant electrical charge. When sounds move the diaphragm, the distance between the plates is changed, and results in a change in the capsule voltage. A high-end resistor measures these changes. The change in voltage is proportional to the movement of the diaphragm. Then, depending on the type of mic, the voltage is processed through a vacuum tube or a field-effect transistor. Some of them then pass it through a transformer, but there are also transformerless mics.

Condenser mics come in every size - from a tiny lavalier mic to the gigantic Blue Bottle, shape, color and flavor. By flavor I mean mics that have ruler-flat frequency responses and aim to capture the most accurate, uncolored sound possible to ones with 'tailored' responses to create a certain sound color. They also come with all different pickup patterns. The pickup pattern describes the mics directionality (or lack therof). Where most dynamic mics are cardioid or supercardioid, condenser mics can be omnidirectional, cardioid, supercardioid, figure-of-eight (more about pickup patterns later on). Many are so-called multi-pattern condenser mics - these can have their pickup pattern switched. One of the most popular multi-pattern microphones is the AKG C414.

The two main types of condenser mics are small-diaphragm condenser (SDC) mics, such as the Oktava MK-012 and large-diaphragm condenser (LDC) mics, such as the Neumann U87. The former typically have half-inch diameter diaphragms; the latter about an inch. Due to their very small capsules, SDC's excell at capturing detail. Their small diaphragms react very quickly to the fastest transients and high frequencies. Another plus is that their off-axis response is very linear. In laymans terms, this means that the sound that they pick up from the sides and behind will not sound strange, like with dynamic microphones. Instead, it will also sound natural, just at a softer level. This is extremely helpful when you have one or more other sound sources nearby (drum set anyone?) or if you're micing from a distance and the mic will pick up some of the sound of the room. SDC's are poorly suited for vocals though, as they take wind blasts very poorly, even with a pop filter. The only remedy is to put some distance between the vocalist and the mic, which can certainly yield a decent sound in some cases. LDC's, though not as sharp as their smaller siblings, are still quite accurate, but many models add some color to the sound, because the fast transients are somewhat 'smoothed out' on a very small scale. Sometimes this is flattering, and there can be such a thing as too much detail (not all of it is always wanted!). Unlike SDC's, their off-axis sound can be somewhat colored, but not as much as a dynamic mic.

Tube condenser mics are known for their 'character'. In contrast to a condenser mic that tries to sound very natural, tube mics have a lot of color, which on some sources can be very flattering or huge. They can also introduce colorful harmonics if you 'push' them a bit. The famous Neumann U47 is a classic example of a tube condenser microphone. It was used extensively to record the Beatles, and many engineers and also mic manufacturers long for its sound. I like them on lead vocals, as their 'agressive' sound helps them stick out in a dense mix, and for lack of better words, can make them sound more exciting and larger than life. With few exceptions, tube condenser mics don't use phantom power, but are supplied with an external power supply unit, which powers these mics.

**thismercifulfate** · 06-24-2011, 12:10 PM

Ribbon Microphones

Ribbon mics are the most delicate of microphone types, but have characteristics that make them very unique and special. They're known to be dark and smooth, and in this era of digital audio are seeing a resurgeance in popularity, also partly due to the influx of cheap chinese ribbon mics.

Their construction is pretty simple: An extremely thin (1-6 microns), corrugated strip of aluminum is tensioned between two powerful rare-earth magnets. Sound waves move the ribbon and fluctuations are created in the mangetic field. Finally a transformer amplifies the signal and sends it to the output.

With some exceptions, all ribbon microphones have a figure-of-eight/bi-directional pattern. They have two very strong nullpoints (points of maximum sound rejection) on the sides, top and bottom and pick up equally from the front and back sides. Some ribbon mics, such as the Royer R121 are designed with an offset ribbon, which gives each side of the mic a slightly different sound. It also increases the SPL capability of the front side. They usually have a similar sensetivity as dynamic mics. Their high-end frequency response curve typically begins to roll off well before 10khz, which is part of why they're known to be 'warm' or 'dark'-sounding. But since the thin ribbon is the only moving part of the mic, it responds very well to transients, but keeps the high-end very smooth sounding, resulting in a sound that is very rich. They're a great choice as overheads for instance, if you want to tame some obnoxiously bright and sharp-sounding cymbals. The Royer R121 is highly popular on guitar cabs, because it captures a sound that can only be described as HUGE and FAT out of them. Beautiful on horns too. They can also add body to a sound when combined with a condenser mic on a source. The Coles 4038 is another popular choice for this. A ribbon mic can also be used as the "side" mic in a Mid-Side recording or for Blumlein (more on these later on).

Ribbon mics must be handled with utmost care in several ways. First, their ribbons are extremely fragile and are highly susceptible to wind blasts. It only takes one puff and the ribbon can tear or permanently deform. This does not mean they cannot handle high sound pressure levels, because they certainly can. They must simply be protected from direct wind blasts, which can be achieved by placing the mic at an angle in respect to the source, or using a pop filter. A ribbon mic on certain female singers can be a beautiful thing and shouldn't be discouraged. They also pick up a wicked sound a few feet off the ground several feet in front of a kick drum. Perhaps it's overkill, but I always make sure to never move a ribbon mic throigh the air too quickly, and I always put it away in its box or cover it when it's not in use. Next, you should never send phantom power to a ribbon mic. While most modern ribbon mics are protected from such, older ribbon mics will be ruined by phantom power. I have heard about reports of sparks flying and smoke...

Another issue with ribbon mics is ribbon sag. Be sure to store all your ribbon mics vertically, so gravity doesn't pull the ribbon to one side, causing it to sag over time. A saggy ribbon will result in decreased sensitivity, output and a muddy sound. An easy way to test for this is to plug in your ribbon mic, listen to it through headphones as you tilt it to either side. A saggy ribbon will cause a "rattling" sound. Ribbons can be re-stretched, or replaced entirely. It's a very delicate task, so you can either order a couple replacement ribbons and have a go yourself, or send it to someone who can do it for you.

Now many of you think a ribbon mic would be a crazy thing to use live/on stage. But I have done so with great results. They have very high gain before feedback and minimal bleed (bleed = sound of other nearby sources leaking into the mic), especially when you strategically position them pointing their nullpoints at your monitors or drums/other loud sources. Certainly not for the faint-hearted though, and I would much rather use a $200 Cascade FatHead than an AEA R44C that costs a couple grand.

I actually got turned on to that particular Ribbon mic when I went to see Pat Metheny live in Portland. He was performing with his Orchestrion. I stuck around during the teardown and I realized they were using 30+ Fatheads and a few other different ribbon mics on just about everything! The sound was really fantastic!

**playinpearls** · 06-24-2011, 01:04 PM

sexy.

is this gonna be an "ongoing tutorial" or just the basics as listed?

(subscribed)

**thismercifulfate** · 06-24-2011, 01:13 PM

Microphone Polar Pattern

All microphones are either unidirectional or omnidirectional.

The above chart shows a 2-dimensional visual representation of 5 common patterns plus some interesting numbers.

Omnidirectional mics pick up sound equally from all angles. As you can see above, their pickup pattern is a circle (or more accurately a sphere). This means they will hear pick up everything going on in the room, along with what you place directly in front of it, if anything. Omni mics thus have a very natural sound, but because they're so open, they have their practical limitations. They're commonly found on laptops, conference tables, cellphones, news-gathering mics, lavalier mics and classical/orchestral recording situations.

Most microphones are unidirectional, and more specifically cardioid. Cardioid gets its name from the Greek term for "heart", looks exactly like its namesake. As you can see on the diagram above, it picks up the most sound straight ahead, diminishing as you go to either side and finally has the maximum rejection in the rear of the microphone. Unidirectional mics are very useful when you don't want a whole lot of room sound and reflections entering the mic and you just want to pick up a specific source. Unlike omni mics, unidirectional mics exhibit what is called 'proximity effect'. This is an increased boost in the bass frequencies as a mic is placed closer to a source. Because of this, when engineers began to mic vocalists very close to the microphones, new microphone models began to incorporate high pass filter switches (bass roll-off swithces), which attenuates the bass frequences of a microphone to counter proximity effect. You can see this demonstrated with a mic placed at 3 different distances from a source on the graph below:

Supercardioid is similar to cardioid, but it's more directional or 'tight', rejecting more sound from the sides than cardioid, but you can see a small lobe in the rear which means it does in turn pick up some, but still very little sound from the rear. Supercardioid microphones exhibit even more proximity effect. They're very desirable when you're micing a source very close to and next to other sources. Take for instance a drum set with 2 rack toms and 2 floor toms. Micing these with supercardioid mics will ensure that each mic will reject the adjacent tom, while focusing on the one it's pointed at. Many bass drum mics are supercardioid, to reject bleed and to intentionally add some bass boost to their sound.

Figure-of-eight or bi-directional mics get their name from the fact that they pick up sound equally from both the front and the rear of the microphone. They however strongly reject sound from the sides. This pattern is found on just about all Ribbon microphones and many multi-pattern condenser mics. It's useful when for instance you want to track a guitarist who also sings. You can angle the mic so that the nullpoint is facing the instrument and one of the lobes is facing the musician and you will barely have any guitar bleed into his vocals. You can also use a figure-8 mic as part of a Mid-Side recording or a Blumlein recording. I will explain more about these stereo mic techniques further on.

Hypercardioid lies between supercardioid and figure-of-eight. It's even tighter than supercardioid, rejecting more sound from the sides, but at the cost of having a larger rear lobe. Audix D series mics exhibit this pickup pattern, which is very nice to have around a drum set.

Wide Cardioid is a polar pattern that lies between Omni and Cardioid. I've used it for instance to record a very large choir in a wide configuration in a live performance, where I wanted to evenly capture the full choir from the center to the sides, but knock down some audience noise. Or sometimes you like the sound of Cardioid but you want a slightly livelier sound, but Omni is too much.

* * *

Now you might be wondering what some of the dotted lines in the last graph might mean. Much like with frequency response plots, manufacturers love to provide perfect-looking polar patterns on the boxes of their mics. But in reality, that graph only represents the mics directional response at one frequency! Yes, a cardioid microphone may exhibit a cardioid pickup pattern at 1000hz, but at 10'000hz many cardioid mics have more of a supercardioid pattern, and down at 100hz some even go more toward the side of wide cardioid.

Some manufacturers, like Milab, whose website I found that wide cardioid pattern graph from, choose to display this. Others don't. Sometimes they don't on the mic's box, but they will on their website. So don't be decieved, it can be important information so do your research.

ElectroVoice has an innovative technology called Variable-D, which is incorportated into some of their most popular mics like the RE-15/16 and the RE-20, which not only reduces proximity effect and minimizes off-axis coloration, but also gives the mic a uniform cardioid pickup across all frequencies. This is made possible with the strategic placement of vents across the microphone that utilize phase cancelation. Impressive!

**thismercifulfate** · 06-24-2011, 01:34 PM

If you're interested in specific microphones, I would highly recommend checking out www.recordinghacks.com It's got a large microphone database with over 1000 mic entries from over 100 manufacturers. You can find pictures, tech specs, general info and reviews on most listed microphones. There's also a blog which has some great reviews, shootouts and more which I think is worth following.

I'd like to state that I am in no way affiliated with that website, I'm just a fan.

**Gord The Drummer** · 06-24-2011, 02:22 PM

With the monstrous amount of information on these subjects I suspect this will remain the basics, but I would encourage anyone with very specific questions to ask them here so that we can contain the information in one thread. This is the first step in the signal chain, so very important information.

There are also several other types of microphones, but they are uncommon. In addition to other types, there are several different "sub categories" of these types of mics, but again it is better to answer on a point by point (question) basis.

Good post Tmf.

**thismercifulfate** · 06-24-2011, 04:00 PM

Stereo Mic Techniques

There are many ways to record a source or an ensemble in stereo. There's a lot more to it than just placing two microphones and voila. I'll run through a couple techniques that I have learnt and that I myself employ. These are all great for messing with your drum overhead placement, but it also works if you want to record a piano, guitar, choir, orchestra, live concert etc... with two mics.

AB Pair / Spaced Pair

This is the most commonly used stereo mic'ing method. Two mics are placed parallel to eachother equal distant from the center of the source. Usually you're placing them the same distance off the floor. They don't necessarily have to point in the same direction, but it's common. The further apart you place the mics, the wider your stereo image will be, but also the more room sound you will get. When mic'ing an acoustic guitar you don't need to have them as far apart as for instance on a piano or a drum set.

Keeping equal distanct from the source is critical, because of one of the mics is closer or farther, the sound will first reach on mic, then the other. If the soundwaves hit the mics so that while one is forming a positive 'peak' while the other a negative one, there will be some cancelling out when they are summed, because your monitors will be trying to push and pull at the same time.

This doesn't mean you won't be able to hear anything. Even when two sounds are 180 degrees out of phase, you'll still hear them, but it will lack bass and sound very weak and thin. Phase cancelation can also [sometimes] happen for instance when you mic a snare from the top and bottom. When you're hitting the snare, the force travels down into the bottom mic, creating a positive wave cycle, while at the same time the void from the downward energy creates a negative cymbal on the top mic. To check if you have phase, listen to the recording in mono (preferrably with just one monitor) and see if you hear a different when you flip the phase on your board or DAW. Listen especially close to the low end information and the "meat" of the sound. It can be only very slight, but it's worth it if you do find there is some cancelation to fix it.

For drum overheads, I would recommend making sure the overheads are equal distance from the center of the snare drum, because it's not only the loudest part of your kit, it's also the center of most setups.

XY / Coincident Pair

With XY, you need to position your mics so the capsules are as close as possible to eachother in the desired position. They are typically angled 90 degrees, but if you want a wider coverage and stereo image you can go as far as 120 or even 135 degrees, which gives you the widest effective coverage.

Note that with this set up using cardioid microphones there is an overlap of the pickup patterns that creates a "hot spot" in the center. You can use this to your advantage, if for instance you're short a snare mic and you want to get more snare into your overheads. Position the XY pair right over your snare, and the overlap will cuase the snare to stand out. If you're recording a vocal group and the soloist/lead singer stands in the center, it also works there. Compared to AB Pair, the stereo image sounds a lot more narrow and focused. You'll get more of the source and less of the room sound, all things equal. If you do want more room, simply move the mics further from the source. XY is an effective way to simply close-mic a source in stereo.

ORTF / Near Coincidental Pair

ORTF is like inverting an XY pair. This technique was discovered by the Office de Radiodiffusion Télévision Française at Radio France, hence the name. There are very specific instructions that are recommended to employ this technique, which came out of much research an experimentation to come up with variables to make the technique reliable and predictable. Normally cardioid condenser mics are used, spaced 17cm apart angled at 110 degrees. Of course you can tweak the angle and space by ear if you feel you can get better results with a slight change.

If you compare this to the XY pair, there is no polar pattern overlap, and the coverage is much wider. The resulting stereo image is very realistic and fairly wide, though not as wide as the AB pair. Throwing up an ORTF pair over the conductor's head gets a very compelling sound from orchestras and choirs. On drum set, it's a great technique if you have most of your cymbals off to the sides and you want the overheads to capture more of the cymbals than the drums, which you'd have close mic'd.

I accidentally discovered that I love ORTF for recording acousic guitar and 12-string. I had finishered tracking a band, and I proceeded to the overdubbing stage. We put away the kit, but we didn't take down all the drum mics, rather we set them aside. When I set the guitar player up, the ORTF drum overheads were still up behind him, so for fun I thought why not position those right over his head, lined up with his guitar? I didn't end up using the closer ORTF pair at all... the overhead pair's sound blew everyone away!

A similar technique is called Nederlandse Omroep Stichting (NOS) from Holland Radio. It has you place the mics 30cm apart and at a 90 degree angle. This technique was developed with playback through stereo speaker systems in mind.

There's yet another variation called Deutsche Industrie Norm (DIN) from Germany that sets the mics 20cm at a 90 degree angle. It's recommended for stereo micing at shorter distances for small ensembles, stereo area micing or instruments like piano.

Recorderman Technique

This is a technique unique to drum sets that I am a huge fan of and that I use 9 times out of 10 when recording drums. It's designed with capturing as full and balanced as possible a sound of a full drum set with just two microphones, but naturally works great when embellished with spot and room mics.

The problem with most of the previous techniques is the lack of kick you'll get into the overheads, since they're all positioned over the top of the drum set, and the direct kick sound goes straight ahead and also back through the batter head. Recorderman has you set up on mic like the left side of an AB pair, and then set the other mic over the drummers shoulder. Here are two pictures I took of this technique from one of my recent recording sessions:

As you can see the top mic is covering the left side of the kit from above, which envelops the hihats, crash, snare and rack tom, and the second mic is looking directly at the batter side of the kick, but also covers the ride cymbal and the floor tom. There is no guideline as to the height of the second mic off the floor, just go by ear and intuition. As for horizontal position, I do like to make sure it has a direct 'line of sight' to the kick batter, but if it's too far toward the drummer or too low, his or her body will block part of the kit from the mic, so you pretty much always have to wing it, because different drummers have different builds, setup and some sit closer to the kit and others further away. Be sure the back mic isn't place in a spot where the drummer will hit it with is right shoulder or arm/elbow. What I usually do is stack two drumsticks on top of eachother (you can also use a measuring tape, string, mic cable etc...) and make a straight line with them from the center of the snare toward each mic. Then I adjust the mics till they are the same distance away. It always works like a charm; I never get any phase issues, even in questionable rooms.

This technique doesn't work too effectively on very large kits, especially with multiple floor toms and cymbals way off to the sides. For those types of kits I usually go for an ORTF set up or spaced pair. But for a 4 or 5 piece with a couple of cymbals it works so well for me every single time. The sound is very complete, balanced, focused and the stereo spread is very realistic. Compared to most of the other techniques, you'll get a drier, less roomy sound overall, which is often quite desirable. If you want less drums and more cymbals, simply point that mics more towards the cymbals.

In the end, which ever technique you choose to try, always experiment with the positioning. If you're not happy with the sound, move the mics. Positioning is as important as the actual mic selection, in getting the best sound you can capture.

**thismercifulfate** · 06-24-2011, 05:00 PM

Two more.

Mid-Side

Mid-Side is the only fully mono-compatible technique of the lot. That's because it's not a 'true' stereo technique to begin with, but it's extremely useful at times and incredibly flexible. The setup comprises of a 'mid' mic pointed directly at the source (usually cardioid, but it can be super/hypercardioid or even omni if you want and a 'side' figure-of-eight microphone, with the lobes facing perpendicular to the "mid" mic. Get the mics' capsules as close as you can possibly position them. You can use two matched pairs, like this pair of AKG C414B-ULS, with the appropriate polar patterns set.

Or you can use a pencil condenser as the 'mid' mic, like this Audio Technica AT4051a, with the C414B-TLII set to figure-of-8.

A popular combo is the Beyerdynamic M130 figure 8 ribbon mic as the 'side' and an M160 Hypercardioid ribbon mic as the 'mid'

Well now you're probably thinking... aren't these just two non-matching mono channels? This is where the really cool part about M-S kicks in: you can adjust the stereo width and you're essentially creating different patterns after you recorded the track! What you do is duplicate the 'side' mic track, pan the first one hard left, and the second one hard right. Then you need to flip the phase on the right one. Then group the two 'side' channels together, and as you raise and lower the volume, you are in control of the stereo width and the overall sound of what you just recorded.

In reality I'm sparing you a whole bunch of math that I can't even get my mind wrapped around, but as you mess with the levels of the 'mid' and the 'side' tracks, it's as if you're virtually taking two stereo back in time to when you recorded the tracks and moving them around. It's the result of phase cancelation that occurs after all the precedures that were done that emulates this. If anyone is interested in getting more in depth.. read here: http://www.wikirecording.org/Mid-Sid...hone_Technique

Blumlein

Blumlein is a stereo and surround micing technique that is the result of two, overlapping figure-of-8 microphones, with one of them turned 90 degrees; the lobes of one mic fill in the nullpoints of the other one. It's a simple method to capture ambience, or an instrument/ensemble plus some room sound. You can use two ribbon mics, like this pair of Cascade Fatheads, which ship with a special blumlein bracket if you buy a pair of them, a stereo ribbon mic like this Stellar RM-7, two multi-pattern condenser mics like this pair of Neumann TLM170R's or the AKG C414B-TLII's above them or a stereo multi-pattern condenser mic like this Neumann USM 69, which has two rotatable capsules mounted on top of eachother:

I love this technique for capturing a room sound or to set in the middle of a choir or orchestra. I helped record a big band once, where we set up each section in rows drawn like the outline of a square, and we stuck a Stellar RM-7 stereo ribbon mic in the center of the square, and during the mixdown we ended up mostly using the sound from that mic, with a little bit of the spot mics for minor balance adjustments and features.

**fakiekid** · 06-30-2011, 05:03 AM

Here are some samples of various close dynamic mics on drums, this really gives you a chance to hear the difference between frequencies, dynamics and importantly spill levels and the effect on off axis colouration. Kit is a rock size Pearl ELX with the Sensitone snare.

Kick: Beta 91, Audix D6, AKG D112, EV RE20 and Audio Technica ATM25
http://www.sendspace.com/file/aep066

Snare: Shure SM57, Shure Transformerless SM57 (mod), Shure Unidyne III 545, BeyerDynamic M201
http://www.sendspace.com/file/2da2lp

Rack: Audix D2, Audix D4, Audio Technica ATM25, AKG D112, BeyerDynamic M201, Sennheiser E604
http://www.sendspace.com/file/ynya12

Floor: Audix D4, Audix D6, AKG D112, EV RE20 Sennheiser E604
http://www.sendspace.com/file/4ubl82

All recorded into a Focusrite Octopre by my 1st year A Level students. Make sure you listen in a studio environment or on good cans!

**Ehrin** · 07-02-2011, 03:05 PM

This is a great crash course in microphones and techniques. Something to remember: there is no "best" technique for micing drums. It all depends on the drums, the room, and the hardware/software being used. Always trust your ears and your engineer.

**thismercifulfate** · 07-04-2011, 01:28 PM

Thanks fakie and Ehrin for your contributions! I completely agree with Ehrin, since each situation is unique it calls to explore the best option. Likewise there is no 'best' mic for something. You could have 5 different guitarists play the same Taylor guitar, and they'll all sound different, so you shouldn't automatically assume you'll get the best results using the same mic for all of them.

Microphones are the very first device in the signal chain. A lot of people like to use an overquoted analogy "the chain is only as strong as the weakest link" for audio signal chains. It doesn't really apply here. Each link in the signal chain degrades the audio signal. If you're using a lesser microphone, or one not well-suited for the source, the less-than-ideal sound will only be made worse each time it passes through a new cable/device (preamp, signal processors, AD/DA converter etc...).

There is a mentality that unfortunately is quite widespread, especially amongst younger audio engineers, that really needs to be thrown out the window: "I'll fix it in the mixdown". People who adapt this school of thought will breeze through their tracking sessions and spend an eternity mixing and ultimately churn out very mediocre-sounding tracks. This is because they don't take time to select the right mic, they're careless about the placement, then they use tons of EQ to vastly alter the sound in the mixdown and other plugins, which when used to a great extent only degrade the signal even more.

The ideal recording session involves getting as close as possible the sound of the finished product you have in mind before you even start mixing. And it can be done, but you have to pay lots of attention to your mic selection and just as importantly, the way you position them. There are also other factors, like pairing up mics with preamps, but I won't touch on those for now. The only rule with microphone selection is that there are no rules or absolutes. If you ever hear someone tell you "always use ____ mic on ____", promptly dismiss it. I'm not saying that you need to dismiss all advice, but I would have a hard time taking someone seriously who makes statements like that. Some of the best ways to capture sound have been and still are found by experimentation or accident. If you follow narrow guidelines and textbooks, you'll never allow for those 'accidents' to happen, and all your stuff will probably all sound the same.

**Gord The Drummer** · 07-04-2011, 01:33 PM

So true TMF.... there is no "I can fix it later". You can't. You can take 5 extra minutes to fine tune a mic, or 20 minutes in the mixdown. Your choice really....

**thismercifulfate** · 07-04-2011, 02:54 PM

Microphone Selection

How do you select the right mic? First off, it helps to really get to know different microphones. You can study all the frequency response plots and specs that you want, but you won't actually KNOW those mics. There's no shortcut... you have to use them frequently, and in many different situations. Only then will you begin to get an idea of how the mic reacts to different sources, positions, rooms, how it blends with other specific mics etc etc... If you're starting to build your own little mic locker, you can start there. If you can, find ways to borrow mics from somewhere, so you can experiment.

There are several different things you need to think about before reaching into your mic locker. The primary factor of course is the source, and the mic's characteristics are also paramount.

Is the source loud or soft? A very loud source needs mics that can handle the high sound pressure levels (SPL's) without distorting, or worse breaking. Mics designed for such often have built-in pads (attenuators), which increase the mics' max. SPL handling level (this is an important spec to know about!). Sometimes, preamps have pads built into each channel, and this can sometimes enable you to use a mic that would normally clip in your DAW with the gain all the way down on your preamp. But some mics, even when used with a preamp that has a pad are not suited for loud sources and will distort nonetheless.

Conversely, a very soft source calls for a microphone with a low level of self-noise. What is self-noise? It is the noise (think of white noise) that the components of a microphone introduce into the signal chain (remember I talked about degradation in my last post?). More specifically, it is the equivalent sound level that the mic itself produces in the absence of sound. This means that this number represents the lowest point of the mic's dynamic range. The AKG C414, for instance, is very popular for orchestral recordings (where you often find performances with p to pppp dynamics and moments of silence), because it only produces 6db's of self-noise. If you don't know what that means, I'll tell you that it's barely anything. You probably don't want to use a tube condenser mic in this situation, as they often have high levels of self-noise, often exceeding 20db's. 20db's may not seem like much, but with your gain levels generally being quite high during the recording of soft music, you will be bringing up the noise level as you crank the gain on your preamps.

Now you know why the AKG C414 is such a workhorse mic! It not only does it have an absence of any major peaks in it's wide freq. response, multiple polar patterns, 4-position HPF's and Pads, it has a self-noise level of 6db, when it's -18db pad is engaged, it has a max. SPL handling of 158db's! Many engineers call it their 'desert island' mic. Alas, I digress...

What range of notes (frequencies) does it have? The following terms and categories are just examples, don't try to categorize everything, I'll explain later. Is it in a general sense an upper register (e.g. piccolo, trumpet, soprano vocalist), lower register (e.g. upright bass, tuba, basoon) middle or full spectrum instrument? (e.g. piano, harp, drum set, marimba etc..).

There is another measurement that you need to factor into the equation, in addition to the above, and that is microphone sensitivity. This doesn't actually refer to the 'sensitivity' in the traditional meaning of the word, so don't be mislead. It refers to how well it can transform sound pressure into output level. In my posts about the different mics I mentioned some typical senstivity levels for the three types of microphones. In practice, it will affect how much gain you will use with your preamp for a given mic. A mic with high sensitivity will put out a much stronger output level than one with low sensitivity, so you'll be amplifying the signal with your preamp less with the former and more with the latter. So you might look at a mic and see it has a moderate to low self-noise level (let's say 14db), but if it's sensitivity is only 1mV/Pa, you know you'll be amplifying the output level of that mic quite a bit with your preamp, unless the source is very loud. But for a soft source, you might want to rethink using that mic.

Although I will get more into this topic later, mic placement is another important factor to consider. Will you be placing the mic real close or further away? Will the source be isolated or are there other sources nearby? Are you trying to capture the full sound of the source or a part of it, and to what extent? Many factors that I have already introduced play into this, such as the mics' polar pattern, proximity effect and frequency response.

That being said, just like with every factor I'm going to mention, you can't and shouldn't base your mic choice on any single factor, because you have other ones to consider. For instance the performance. What if you got out your favorite bass mic for an upright bass, and the musician ends up only playing in his highest two octaves? You need to know this before take 1, otherwise you'll look a bit silly running frantically to change out that mic. Or worse, what if take 1 was "IT"? You already messed up, because you didn't find out everything you need to find out before hitting the record button. Don't set up your typical drum mics only to have the drummer pull out his brushes, mallets or play with his hands and make you look stupid. The lesson here: Always listen to the band first. Find them on youtube or facebook, sit in during a rehearsal, and if neither are possible, have them play the actual tunes they want to record during the set up or as you're settling levels (and that for more than just that reason). Every instrument (with very few exceptions such as the harpsichord), has a decent dynamic range, and you have to be prepared for anything!

Another thing you need to consider is the end-product. Do you want to capture the source as naturally as possible, or are you going for a certain sound, that is unlike it's natural sound? Either path is equally valid, although each one also has it's place. Generally for situations like classical and chamber recordings, you don't want to alter the sound at all. But for a pop or rock session, it's commonplace to explore new and different sounds. A microphone can either accurately translate a source's sound, compliment or flatter it, do it no justice, mask some of its traits or anything inbetween these.

Vocals are a great example of this. If you have a really whiney, nasal-sounding tenor, you probably won't reach for a mic that will accentuate those traits of his voice, or even one that is very accurate sounding, unless that's what you're going for. If you have a drummer with cymbals that have a very brittle and harsh top-end, you probably don't want to reach for your brighter-sounding condenser mics. Some ribbon mics might be the ticket, since they have a very smooth high-end response and will tame the sound of those cymbals. Hopefully you get the idea.

Now that you've read this, look at all the important things that someone will completely ignore and overlook that simply throws up some mics and tries to fix in the mixdown. You can't fix that kind of stuff... you need to get it right!

**thismercifulfate** · 07-04-2011, 04:35 PM

Microphone Placement

I briefly touched upon mic placement in my last post about mic selection. That is because you don't first select the mic and then place it. You have to already be taking the general placement of the mic into consideration when you choose it, just as you're taking into consideration what source you're capturing it with, as well as the performance, context etc..

The placement of a microphone can be very finicky. There are many factors that play into it, such as the room it's in (size, shape, treatment or lack thereof) and its corresponding acoustics, whether your source is isolated inside the room or if other sources are present and more.

There are different ways to mic a source:

Close Miking:

Also called spot miking, with this position you are capturing the source from a close distance, which can be anywhere from several feet to almost touching (or touching, if you're using a pickup type mic). In a session where you are using all different forms of miking, close miking gives you control: the possibility in the mixdown to bring out that source in a mix with many other sources. In terms of sound, close micing captures the most direct sound relative to reflected/room sound. The sound a mic captures from up close can be very detailed and very 'intimate', but it's also not a sound we're necessarily used to hearing and may not sound natural. Afterall, when at a show have you ever stuck your head inside the bass drum, next to the F-hole of an upright bass, or up to the lips of a singer? Just some food for thought.

Area Miking

A great example of area miking is drum overheads. Whether you want them to capture a balanced, overall sound of the kit or mostly the cymbals, you're miking an area, not an individual part of the kit. When recording an orchestra, you don't necessarily need to spot mic every single instrument; it's more practical to mic sections of it, like the low brass, the violas or the french horn section. While you give up control of individual musicians, you can still easily balance the orchestra this way in the mixdown. Obviously the placement is further away than with spot miking, but the placement is strategic to capture a specific area or section. This will also introduce more bleed, but again it's not necessarily a bad thing. It can give your recording a fuller sound. Using directional mics, careful placement and baffling (using acoustic baffles for isolating sources from eachother somewhat) can help knock down the bleed if needed.

One thing to think about when comparing close and area miking is sound development. Guitar cabs are often seen with the cloth grille removed and a mic stuck bare millimeters from the exposed speaker cone. A mic positioned like that is only (intentionally, or maybe not?) capturing part of the guitar cabs sound. The more it's pointed at the center of the speaker, the brighter the sound will be, because that's the part of the speaker that reproduced the higher frequencies, whereas the edge of the speakers produces the lower ones. A mic positioned a few feet back from the cab would capture more a blend of the overall sound. Some distance lets the sound develop, and also introduces some of the room sound, which can be a great thing. Engineers love to stick a Neumann U47 FET condenser mic a couple of feet away from a bass drum. Sometimes they build a tunnel, to knock down bleed and room sound. Why? Because out there the sound of the kick has developed, and desireably balances all the traits of the kick. That same sound cannot be found inside the bass drum, or inches off the front head. Try it out yourself, it sounds huge! In fact, just try kneel down in front of a kick, plug one ear and have someone (lightly!) play the bass drum.

Room Miking

Room mics do exactly what their name suggests: They capture the room. Whereas spot and area miking focuses on the source, the room mic is often not even pointed at the source, or they are often omnidirectional mics, because their aim is to capture the sound of the room's response to the source. Here your reflected to direct sound ration is the greatest; these mics capture more soundwaves that have not travelled directly from the source to the mic, but rather the ones that have gone in other directions, bounced off surfaces and travelled more distance before reaching the mics' capsule. So when you introduce a room mic track into a mix, all else equal, you're not only hearing a different sound than your close and area mics, but you're also hearing a delay, because the soundwaves reached the room mics later in time than they did the close mics. This delay between the sounds of the close mic tracks and room mic tracks is part of what creates a sense of space.

Remember the Mid-Side mic technique? The 'side' mics are essentially room mics - rejecting the direct sound and capturing reflections, whereas the 'mid' mic can is an area or close mic.

Naturally, the room itself plays an immense role in the sound that your room mics capture. Studios tend to have larger rooms (they simply tend to sound better and give you more options for placement) that are acoustically treated, to make sure no frequencies are being overemphasized in the room. The walls are not parallel to prevent standing waves/flutter echo and sound cancelation (like in your bedroom or garage). A room can be designed and treated to have a more lively sound (more reflective surfaces) or to have a very dead sound (lots of diffusion and absorbtion). Big studios will have both types of rooms. And each room will have sweet spots to place the source in, and also to place a mic in, depending on where the source is. These must all be explored. But if your room simply sounds bad, you probably don't want to introduce any room sound into your recording.

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