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FEATURE ARTICLE

DECEMBER 1, 2000 ISSUE

HOME RECORDING PRIMER - PART 1

BY ROBERT DENNIS

The Home Recording Quality Syndrome
The first few home recordings that are made initially sound very good to the new recording enthusiast.  The very fact that you installed recording equipment in your basement and used it to record something makes the result sound very good to your ears.  When you play it for family and friends, they will join in the chorus of "sounds great."  The fact that you are producing recorded product at home will initially be impressive to them as well.   
Somewhat later it is likely that reality will set in.  If you continue to record in your basement setup, you will begin to notice that your home recordings don't sound all that good compared to released CDs you can buy in the record store.  The quest will be How do I correct my poor recording quality that I get at home? - the subject of this article.
You will discover the truth eventually.  Your home recordings don't sound as good as they could for several reasons.  You can't, for instance, just run out and buy a couple of mics to make the problem disappear.  We will present a step-by-step rundown on how to improve your home recording quality.
Getting Rid Of The "Basement Sound"
Micing Techniques for Capturing What's Really There,  Minus The Room:
Believe it or not - most basements don't sound all that good.  Perhaps the first objection you will have to your home recording is that it sounds like it was made in a basement rather than at a good-sounding concert hall.  In a May, 2000 series of tips, we outlined several techniques and approaches to recording.  The second technique was to "get the room out" of your recording. 
By far, the most popular approach for multitrack  studio recording is to capture the sound of the instrument and to put it "into a performance venue" in the mix.  What I mean is although you record it in the 12th street studio, or in your basement, you have the final product sound like it was recorded at a large performance (like say at Carnage Hall).  The idea is to get predominantly direct sound off the instrument when it is recorded and to add artificial reverberation later in the mixdown
Sound Pickups for Capturing What's Really There:
The first kind of sound pickup is a micing technique is called "Close Micing"  where the microphone is placed within a foot of the instrument making the sound.  This type of technique captures almost no room sound and makes it possible to get the closest to the furthest sound in the final mix and to also put its sound into any performance setting in the mix with the use of reverberation and equalization.
The second type of sound pickup can be used with electric and electronic instruments.  The technique is called the "direct pickup" or the "direct injection" method.   An electric bass puts out an audio signal, not sound.  You hear the bass line because the bass player has an instrument amplifier.  The direct pickup (done by using a "direct injection box"  routes the audio output of the bass directly to a console input.  This same kind of pickup can be used for synthesizers and for guitars.  You should have a word of caution regarding guitars;  that is that most guitarists get their sound from the instrument amplifier and from the speakers of that amplifiers, so a direct signal from a guitar may not sound anything like the guitar does.
The third type of sound pickup used for this technique is the "near-distant" micing technique where the microphone is placed 3 to 5 feet away from the instrument.  Some instruments don't really generate their sound until you get about 3 feet away.  This is true for piano that spreads sound out over a large area as well as for woodwind instruments which generate sound from almost the entire length of the instrument's body (from the different holes).  Even most rock guitar amplifiers, which generate sound from multiple speakers, don't have full sound until you are about 3 feet from the cabinet.
Acoustical Adjustments for Near-Distant Micing:
When a microphone is placed 3-5 feet away from the instrument, you begin to pick up the room sound (the room reverberation) of the recording setting.  To help prevent this pickup, movable isolation baffles can be used to cut down room reflections.

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FIGURE 1 - THREE SOUND PICKUPS - TECHNIQUE 1

Using Baffles For Isolation:
To full utilize this tip, we have to use baffles to help control,l the sound reflections in the basement, but most home recordists don't know how to correctly use them.  Its easy to set them up backwards.  

Because of the reflective nature of sound we can usually achieve the best sound isolation by placing the absorbent baffle behind the very loud or very soft instrument. Directional mics are placed so that they point into the baffle; this rejects any sound coming into the area because the back of the mic doesn't pick up sound well. The sound absorbing baffles prevent reflections of sounds from bouncing into the mic. The musician is placed between the mic and the baffle, with the musician's sound projecting into the front of the mic. Figure 4-1 shows this set-up.

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Figure 4-1: Placing Sound-Absorbing Baffles For Isolation

Figure 4-2 shows a common problem that can happen when the baffles are placed between instruments to get isolation. Some of the direct sound from the instrument amplifier is blocked, but some of its sound will bounce off surfaces around the baffle directly into the front of the directional microphone. Placing the baffles behind the instrument, as in Figure 4-1, will usually do a better job than trying to use baffles to "block" the sound, as in Figure 4-2. Baffles behind have the added benefit of not blocking the musician's view. In extreme cases, baffles can be used on all sides of an instrument.

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Figure 4-2: Incorrect Placement of Baffles

Placing sound absorbing baffles behind the musician will allow good line-of-sight contact between musicians and this helps them play together better. Placing sound absorbing material behind a loud instrument reduces the sound projected into the room almost by half. If a loud instrument is in front of an acoustically reflective surface (like a hard wall), the loud sound bounces off this reflective surface into the room. Sound absorbent material prevents this additional reflected sound from being made. Figure 4-3 shows loud drums next to a wall projecting sound into a room. Figure 4-4 shows the same drums with sound absorbing baffles behind them.

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Figure 4-3: Drums Projecting Sound Figure

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4-4: Drums With Sound Baffle

Inexpensive Baffles For Home Recording
After you realize that you may need baffles, you find that you don't have any.  If you price the baffles (or the components you need to build some) you can find them expensive and out of your budget.  Is there any inexpensive way to do the same thing? 
The home recordist is usually working with a limited amount of space.  Often the live musician performing is in the same room as the console and the musician is playing in the corner or across the room.   There's not a lot of room for big baffles, like there is in a larger professional recording studio.
Big baffles can be expensive, even when built with minimal costs, and for what?  To take up most of the limited space that a home recordist has - naturally.
So I decided to design a home baffling system that the home recordist can actually use.  The system I designed will fit into any setup and cost a mere $3.00 (or $5.00 if you don't watch costs).   Probably everything you need can be picked up at your local dollar store. 
 
One takes a corner of the room and hangs blankets 6 to 8 inches away from the wall.  This "L" shaped area has reduced leakage of other sounds in the room because the sound waves have to travel through the blanket to the wall and back through the blanket to form a sound reflection.   The air space between the blanket and the wall helps make the blanket effective.  
So you get those hooks and clothesline that will hold the blankets.  You use things like clothespins to keep up the blankets.  (see figure 4-5, to the right)
Needless to say everyone has blankets and you can't use your sleeping blanket while you're recording.   You would want to use the thickest ones or even have two layers of blankets [Two thin blankets work better than one thick one, by the way].
So your little corner becomes your baffled-off area and things sound better there and have less leakage.

 

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FIGURE 4-5

The Importance of the Pickup
It never ceases to amaze me how some home recordists will pay thousands of dollars for digital workstations, consoles and/or recorders while they use some cheap microphones purchased from the "Shack."  Somehow they expect that setup to yield a good recording!  A $100,000 console in the hands of the best engineer can't compensate for improperly picked up sound - poor microphone selection and placement.  As a long-time associate of mine has said, the rule is:  "You can't make chicken salad out of chicken shit." (excuse the technical term "shit")
If you have a tight budget (and who doesn't?) you may have to spend the majority of your money on microphones.  After you have an adequate microphone "locker" you can start investing in better consoles, recorders, etc.
Going out to the "Center" and purchasing the right microphones for home-recording bands will cost you a minimum of $1600- $1800.  If you are only going to do rap & hip-hop, or if you use synthesizers & drum machines for all your music, you really have to spend about $700 - $800.  Only those doing "all electronic" music forms like acid and rave can afford to have inadequate (or no) microphones.
So if this amount of money is unavailable, what to do?  Get as close as you can or be really smart and purchase a subscription to Pro Audio Marketplace (See our tip for November, go  here).  Sensible purchase of used microphones can greatly reduce the amount you have to spend at the sacrifice of spending the time to find the bargains. 
Getting the Pickup:
There are different types of microphones.  Each type picks up certain types of instruments the best.  There are condenser microphones (more expensive) and dynamic microphones.  You will need both, as described below.   The first step is to get a microphone that will pick up the intended sound source; for this purpose, there are two types of microphones:
 

Sound Quality Mics are microphones where the diaphragm can move quickly.  This type of microphone is needed when you have a loud blast of high frequencies (like cymbals) and where perfect sound quality is needed (vocals).

Examples of these microphones include the ribbon mic, the small diameter condenser microphone (half-inch diameter diaphragm) and the large diameter condenser microphone (1 inch or larger diameter diaphragm)
Moxy Mics are microphones where the diaphragm can move far. These type of microphones are also the most rugged.  This type of microphone is needed for loud bass-frequency pickup and bass-frequency transients as found on low-frequency drums (such as the kick and toms) as well as miced rock bass.
These microphone are all dynamic mics and include large and small diameter microphones, as well as models of modern and older designs).

KEY:

Best

Questionable

Poor

Very Poor

Sound Quality Mics

Moxy Mics

Large Dia Condenser, Like Shure KSM or Ribbon

Modern Large Diameter Dynamic Like EV RE 27

Small Dia Condenser

Large Diameter Dynamic Like EV RE 20

Modern Dynamic Like Shure Beta and EV N-Dyn

Smaller Diameter Dynamic Mic Like Shure Beta 57

Older Better Quality Dynamic Like Senheizer 427

Any Ribbon Mic or Cheapie dynamic

Older Dynamic Mic

Large Diameter Condenser like Shure KSM or AKG 414

Cheapie Dynamics

Small Diameter Condenser Mics

The Microphone Locker:
If you're going to record bands, you need a minimum of 6 microphones.  Two dynamic mics ("Moxy Mics") will pick hp the foot drum and the snare drum.  Two condenser mics ("Sound Quality Mics) will be used to pickup all the rest of the drums and cymbals.  Two additional dynamic microphones will be needed to pick up other instruments, such as guitars.  In addition you will want to have a minimum of two High to Low Impedance Transformers to take electric or electronic instruments direct to the console ("direct injection").
As you can afford it, you will want to increase your microphone locker so that you can individually mic more of the drum set by adding 3 dynamic microphones for the toms and a condenser microphone for the high hat, as well as another condenser microphone for vocals and melody instruments.  Thus your locker will increase to about 11 or 12 microphones.
If you are going to limit yourself to rap and hip hop productions, you need only two microphones (a condenser and dynamic microphone).
Starting Suggestions:
As you get more microphones, the variety of model numbers that can be used should increase.  If you are starting out, you will want to get the highest quality and flexibility for the budget.  Two microphones that would be a good starting point for the 5 microphone basic "starter locker" would be two Shure KSM series large condenser microphones and four Shure Beta 57 microphones. 
The KSM condenser microphones challenge the solenoid of the best microphone available but at a  rock-bottom price.   For a hundred dollars less per microphone you could come up with a condenser mic but the difference in quality is dramatic - consider the KSM.  You can but the "standard" mics, the Shure 57's  could be used but have half the quality of the Beta 57 models, which cost about $50 more at the store.   
Whatever models that you settle on, you should try to buy in pairs (two of the same mode) because stereo micing should have matched types.  You will also experience that day that you are happy that you have four identical models of dynamic microphones.
Placing The Microphone
You can read various microphone placement charts and formulas about how to place microphones to pick up the sound projected from the instrument.  Sometimes placement charts work well, sometimes they don't work as well (usually because of the presence of other sounds in the room), but what always works is to USE YOUR EAR.
Notice I said to use your ear (singular) not use your ears (plural).  The microphone is mono and your ears are stereo.  Put a finger in one of your ears and place the other ear where you would place the microphone.  Have the musician play and move your head around until you have the "best" sound - put the microphone there.  It is really that simple.
One word of caution.  Be quick about it if the instrument is loud.  If you stuff your head inside a foot drum or two inches from a snare for any length of time you won't be hearing much very quickly.   If the instrument is loud and if you want to take the time, you can alternately hook the mic up to the board and wear headphones as you move the mic around by hand.  Although this technique could work it just isn't as much "fun."
Microphone Directionally:
When we talked about baffles, we mentioned using directional microphones.  The two most common pickup patterns are the cardioid (as found on the Shure SM-57) and the hyper-cardioid (as found on the Shure Beta-57).
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FIGURE 4-6 - CARDIOID PICKUP PATTERN

FIGURE 4-7 - HYPER-CARDIOID PICKUP PATTERN

In general, the hyper-cardioid pickup pattern does a better job of rejecting other sounds in the room.
Pointing Directional Microphones:
If you only have one instrument present and a good-sounding studio, you don't have to worry much about pointing the mic.  If you have other instruments playing in the same room, especially drums, pointing the microphone becomes all critical.  The first rule of pointing a microphone is:
1. Point the front of the microphone at the instrument or other sound source.
2.POINT THE REJECTION OF THE MIC AT WHAT YOU DON'T WANT TO PICK UP.
The microphone you are using will most often have maximum rejection in the back (this is called a cardioid pattern).  You can point the front of the mic at or up to 45 degrees away from the instrument and still get full (or almost full) pickup.  Thus pointing the front of the mic is not critical (hence the small letters).  If you are using a hypercardioid patterned microphone your rejection point is 120 degrees from the front of the mic.
95% of pointing a microphone is to reject unwanted sounds.  If you are off by 10 degrees, your "leakage" will increase 300%. 
Preview of Part Two
Next issue we will move to the control room to give you "getting started" advice for using consoles and tape machines for recording and getting a  mix.

Copyright 2000, by Robert Dennis, ALL RIGHTS RESERVED

Published in Recording Engineer's Quarterly and Alexander magazines with permission

USE OF THIS ARTICLE SUBJECT TO USER AGREEMENT

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