Mic choices, placement, and effects to make your horns sing
By Michael Schulze
A horn section can give a unique emotional impact to an otherwise ordinary track. Hard to describe, easy to hear. Imagine the Beatles’ “Got To Get You Into My Life” without the horn section that opens the song. Who among us has not been inspired to jump around like an idiot in a public place by James Brown’s horn section? Steely Dan was a band that used horn arrangements as early as their second album, Countdown to Ecstasy. Check out the alliterative horn lick in “My Old School” after the line: “California tumbles into the sea”. The jazzy sound of horns added a slick sophistication and became an integral part of the Steely Dan sound. Horn sections were a big, big thing in big 1980s pop, and also in less mainstream musical genres like ska and reggae. Bands like Tower of Power, Chicago, and Blood Sweat & Tears are synonymous with horns.
The term “horns” in the way we use it here is not strictly legit—in the context of jazz and other non-symphonic styles “horns” means any wind instrument. Therefore “horns” in this usage of the word are divided into two families: brass and woodwinds. We’ll stick mostly to a discussion of brass and saxes as they’re the instruments typically found in rock, pop, and soul “horn sections.”
I meet lots of audio enthusiasts who say things like “horns are the hardest thing to record.” Their frustration usually stems from an unfamiliarity with horn music and horn players. If you have never gone to a jazz club you may feel mystified by horns and horn players, but honestly, these are some of the most straightforward instruments to record. Bagpipes—now there’s a difficult instrument to record! (We won’t go there…)
Brass players “buzz” their lips into a small cup-shaped mouthpiece. This mouthpiece fits into the tubing of the trumpet, trombone, tuba, french horn, or other brass instrument. The tubing of the horn acts as a complex filter and resonator to transform the obscene raspberry sound of the buzzing lips into the beautifully complex tone that comes out of the business end of the horn, which is called the bell.
Brass instruments these days are completely sealed except for the small hole in the mouthpiece and the larger hole in the bell, so the bell is where mics will pick up the brass instruments’ sound. Practically speaking, all the sound shoots out the bell in a pretty directional beam pattern, much like a shotgun blast starts out as a narrow cylinder of hot lead and spreads out somewhat as it hurtles blisteringly to its destination. Am I starting to convey the devastating power of trumpets and trombones? I hope so.
Woodwind instruments may not all be made of wood. They include the single-reed instruments, namely clarinets and saxophones, the double-reed oboe, English Horn (a lower-pitched oboe) and bassoons, and the reedless flutes.
Clarinets and saxes use a reed, a thin little sliver of bamboo clamped to the mouthpiece; the free end of the reed vibrates as the musician blows air into the mouthpiece, and then those vibrations excite the column of air in the instrument.
Saxophones and clarinets have holes along much of the body of the instrument; these holes can be opened or closed by the keys that the musician activates with his fingers. The bell at the end of the clarinet and saxophone conveys only a part of the sound, any open hole on the instrument is also producing sound. As a result, these single-reed woodwind instruments will radiate sound in a much wider pattern than brass, and microphones must be placed in such a way as to receive sound from the holes and the bell.
It’s all about the tone
Recording horns is all about the tone. Horn players use parts of their body to produce their sound, and they work for years just to get their tone right, so tone is a very personal thing with them. After years of struggle they know what they want to sound like, and a little knowledge will help you capture that sound in a way that will please your performers and your listeners.
Most brass and reed instruments you are likely to record play notes in the range of 110 Hz to 1.8 kHz or so. However, these instruments have very strong harmonic content in the range of 2 kHz to 5 kHz, which is what gives them their “bite” and “edge”.
If you have ever been frustrated with trying to record brass or reeds, it may have been because you were getting too much bite and edge. This frequency range also happens to be the range in which the human ear is most sensitive, so these instruments need to be reined in a bit. I mean—these things go off like a Howitzer! I once saw an unamplified alto sax player break a half-full beer glass on a table a few feet away! But I digress.
Because these instruments already have lots of energy in the 2–5 kHz range, it is important to use a mic that does not overemphasize this area. Perhaps you’ll even settle on a mic that de-emphasizes this area. First of all we will assume that you need a cardioid polar pattern, sometimes referred to as unidirectional. This is a microphone that picks up sound from the front and rejects sound increasingly as you move off to the side. The rest of the decisions you need to make are to insure that you choose a microphone that is complementary to the already bright sound of horns.
For recording horns in the studio you will most likely want to use a condenser mic, because condensers generally have a smoother frequency response than dynamics. Condenser mics come in large and small diaphragm sizes—the diaphragm is the circular disc inside the capsule of the microphone that converts acoustic energy into electrical energy. A large diaphragm has a diameter of about one inch. The larger diaphragm size means larger mass, which makes the microphone respond a bit slowly. This softens transient response and imparts a warmer, rounder sound to most large-diaphragm mics. Large-diaphragm mics also tend to reject sounds arriving from the sides better than small-diaphragm mics, so chances are they will do a better job of not picking up the other instruments in the room.
So now we are getting closer to specifying our ultimate choice! Look for a large-diaphragm condenser without a frequency boost in the 2–5 kHz range. A classic choice for trumpets, trombones, and saxophones is the Neumann U 87. The frequency response curve of the U 87’s cardioid pattern is flat and uniform between 70 Hz and 5 kHz, with a gentle rise after 5 kHz, leveling off at a very subtle 2 dB boost between 8 kHz and 10 kHz. This microphone is going to leave the already bright 2 kHz–5 kHz range alone, and instead give a very gentle boost around 10 kHz, which is going to give a bit of “air” or “openness” to the sound.
Now, a Neumann U 87 will set you back a couple thousand dollars, so if you can’t come up with that kind of scratch, there are some very reasonable alternatives from a whole bunch of mic manufacturers from the USA to England to Australia to Japan and yes, even China. Look for a large-diaphragm, cardioid condenser with a frequency response chart that looks kind of like the U 87. Try to find a mic that does not boost 2–5 kHz, and boosts no more than about 4 dB above that frequency range. Remember—you are looking for a mic that would be considered not quite bright-sounding enough for some other applications.
Come over to the Dark Side
The mics I have described so far will tend to produce a pleasingly brilliant sound without too much edge. This is an excellent approach to recording horns that will have to compete with electric guitars and bright synth patches in a pop mix.
However, sometimes we are looking for a dark or somber tone, perhaps for a relaxed and mellow solo in the middle of an R&B ballad. In this case you may consider a ribbon mic, which uses a thin ribbon of aluminum suspended within a magnetic field to produce a signal. These mics are some of the smoothest-sounding available, and can produce a rich and creamy complexity in the lower midrange.
The frequency response chart for the beyerdynamic M 160 exhibits a very gentle rise between 1 kHz and 10 kHz, but what the diagram does not tell you is that a ribbon mic responds a bit more slowly than a condenser due to the higher mass of the ribbon compared to a condenser diaphragm. This tends to produce a pronounced darkening of the sound—a sound so soft you could use it for a pillow!
There are now some very affordable ribbon mics from Cascade and Oktava among others—you’ll have to listen to them to see if they rise to the quality level you need. As your mic budget and demands increase, check out higher-end but still fairly affordable ribbons from beyerdynamic (M 160), AEA (R84 and the NUVO N8 and N22), Royer Labs (R-121, R-101, and others), and Coles (4038 or 4040)—all excellent choices.
Location, location, location….
Microphone selection is half the battle, but even the otherwise perfect mic will sound like garbage if it is not exactly in the right place! Let’s talk first about recording trumpets and trombones, which are called “bell-front” brass instruments because the bell points forward.
Placing a mic in front of a brass instrument is a simple matter. If you just remember that the sound is shooting straight out from the bell in a beam-like pattern, it becomes quite obvious that the mic should be pointing straight into the bell, as if to catch this shotgun blast of sound!
The best way to do this is to ask the player to ignore the mic and play for you. Once you see where the player holds the bell of the horn, place the mic so that it is 6 to 12 inches from the edge of the bell pointing straight “up the bore”, which means right into the bell. Make sure to have the player play before you place the mic, for if the player has to hold an unnatural position to play into the mic, eventually he or she will get tired and the bell will wander away from the mic. Because bell-front instruments are so directional, it is crucial that the bell not move around at all or the sound will not get into the mic at the angle that captures the full tonal quality!
Placement for reed instruments takes a bit more thought. On live gigs with rock bands, saxophone players like to get their bells right up onto the mic to avoid leakage from other instruments, but in the studio, with condenser mics, this can produce a rather harsh and unnatural sound. I still recommend a distance of about one foot to start, but you need to get the mic into a spot where it will pick up sound from the bell and the holes. For alto and tenor saxophones this is easy. The mic needs to be about one foot away from the bell at about a 45-degree angle up from the bell, but pointed at a spot between the bell and the player’s left hand. This way you will catch the sound from both places.
For straight reed instruments like soprano saxophone or clarinet, things get more tricky. There really is no way to place the mic close enough to get a present sound, yet far enough to balance the bell with the holes. The easiest solution is just to point the mic at the holes. The mic is still about a foot away, pointing at the spot between the player’s left and right hands. This placement will produce a very warm and realistic sound, a sound that is preferred by many jazz musicians.
Placing the mic below the bell at a distance of only about 6 inches will produce an acceptable and yet very different sound, brighter and more reedy. This may be appropriate when you are looking for a more edgy sound that will cut through a dense mix, but it will not sound as “natural” as the first approach.
An excellent compromise can be had by using two mics, one placed above the keys and one placed below the bell. The engineer can then blend the sound of the two microphones to get the smoothness of the upper mic with the presence of the lower mic. This approach is often used to amplify these types of instruments, because the upper mic can be a bit closer, which will give you better gain before feedback. Pan the mics to the same position in the mix and experiment until you get the best balance of the two.
The nearness of You
Directional mic capsules exhibit proximity effect, which means that as the mic gets closer to the sound source it starts to exaggerate low frequencies. Vocalists, especially announcers and voice-over people, use this effect to their advantage, moving in close to the mic to get that big, rich, gravelly sound.
When recording horns, the engineer can use subtle changes in placement, moving closer to produce a warmer sound, or farther away, perhaps as far as two feet, to thin things out a bit. Be careful, though, as getting too close or too far can start to have adverse effects as well. My advice is to start at a distance of about one foot and experiment moving closer or farther away by about 6 inches to see what happens to the sound.
If you have obtained the proper equipment and done due diligence in the careful placement of your mics, you should be able to achieve a very pleasing sound that requires only a little processing to nudge it into place in your mix. Careful use of equalization can help, but I recommend you record your horn tracks straight to tape (am I showing my age again?) or DAW and perform any processing downstream from your recording medium.
I most often find myself trying to remove a little more edge from the sound by cutting by about 2 dB at around 3 kHz. Perhaps after that I will boost about 2 dB at around 10 kHz to compensate for the loss of presence. This 3 kHz reduction might not be necessary at all, but try to avoid boosting anywhere near 3 kHz unless you really want a more edgy sound. The 10 kHz to 12 kHz range is a much safer range to boost if you want your horns brighter. Be careful, though, to avoid making the sound shrill.
After your equalization you will find that a touch of compression will help keep your horns sitting pretty in your mix. Compressor settings that work well for vocals usually tend to work well for horns as well. A ratio of 3:1 with a fast attack (5–10 milliseconds) and a slow release (80–100 milliseconds) is a good place to start.
For a high-energy mix go for 3 to 6 dB of gain reduction at the loudest part of the horn track. A more mellow track might call for only 3 dB of gain reduction at the loudest part. Also, avoid setting the compressor’s attack time too slow, or the attacks of the horn notes will pop out before the compressor can react. In small doses, this effect can add a nice punch to the beginnings of notes, but if your attack is set too slow the horns will start to take on a slappy, spitting sound.
The ears have it
In the end it is the sound that counts. When in doubt, use your ears. It helps to have a CD handy that has some horn tracks you like. Go through the steps I have outlined, in order, and try at each step to nudge the sound a bit closer to the sound you hear on the CD. This will help keep you focused on the sound you seek, and keep you focused on your ultimate target—horn tracks that have power, punch, and passion.