Do You Hear Something? - Eliminating Hums and Buzzes

A lot of guitarists have discovered the many benefits of owning a home studio. You can record at any time, day or night. You can experiment radically with effects and recording techniques. You can learn a great deal about the recording process, and what makes a great track or a killer sound. If it requires 50 takes to record a great solo, then you have the freedom and unlimited time to record that great solo. Best of all, with the escalation in quality of home recording gear, it is possible to create your master tape(s) without ever booking time in a 'real' studio. The amount of money required to outfit a master tape quality studio has dropped to the point where it is to any musician's benefit to consider putting together a writing/rehearsing/recording space that can be used for multiple projects.

Those of you who already own a home studio, whether it's modest or quite extensive, know that a lot of responsibility comes along with the benefits of freedom. Most recording equipment requires at least some minimal maintenance. It's now your job to troubleshoot connections and eliminate squeaks and rattles. Without engineers and producers around, all the decisions about what to do and how to record are yours. There may be many times where the opinion of someone else would help to create a better track or enhance a mix - will you end up simply settling for mediocrity?

All home studio owners will definitely benefit by at least attempting to find other musicians (in your local area or all over the world on the Internet) that also are recording in home or project studios. By sharing our common experiences and individual knowledge we can all benefit greatly, and the odds of us all achieving our goals are increased. At Guitar Nine, we are starting a registry of home studio owners on the Internet, so that when you've made the decision to go it alone, you can at least find help and support within the global community.

In the meantime, there are plenty of time-tested tips and tricks that you may not have thought of, or may have known about and forgotten, that you can use to enhance your home-studio tracks and reduce the chances of having to book time at $100 an hour. There are probably an endless number of ways to improve your studio and your music. This topic lends itself to a regular update of new tips and ideas. Without further ado, let's look at some more ways (check out the original Tool Time: Home Studio Tricks and Tips) to improve the output of your home studio.

Poor Recordings And Performances: Remixing May Save The Day

1. Let's face it, sometimes a vocal performance can be slightly out of tune throughout the entire song. Two tricks that may help involve the use of chorus and pitch shifting effects. Running the vocal track through a chorus helps thicken the sound and since the chorus effect works by manipulating the pitch of the source sharp and flat, the original vocal part will appear to be more in tune than it is. If the vocal seems consistently sharp or flat, using a pitch shifter allows you to shift the pitch a few cents to compensate, and you can try blending the shifted vocal back with the original for a thicker sound as well.

2. One of the biggest problems that can cause mixing problems is excessive drum track leakage. You spend two hours setting up six microphones to record six separate drum tracks, and after it's all recorded, the snare track sounds more like a composite snare, cymbal and tom track! This creates a problem when heavy processing (reverb, flange) is required on the snare drum alone and not on the rest of the kit. In this case, hauling out a noise gate and processing the snare track alone will help to ensure only the snare drum is heard, and not the 'noise' between snare drum hits. It's important to experiment with setting the proper attack time (fast) on the gate so that the start of the beat is not cut off. Also be careful when setting the threshold on the gate; if it's set too high, then you'll risk cutting off the beginning of the beat, because it won't be quite loud enough to open the gate. Once you have the threshold set such that the snare drum sounds clean, listen carefully to the whole snare track in solo. You may have inadvertently set the threshold too low, and unwanted sounds are popping up occasionally. You may have to make a subjective call on the threshold setting, trading off a few undesired sounds for a cleaner snare drum attack.

3. You might have a situation where the sound of the bass guitar track is just not satisfactory. If the bass guitar is competing with the bass drum, try boosting the bass guitar at 60-70Hz with your low EQ, and cut the bass drum track slightly at the same frequencies. This will help separate the two sounds in the mix, while also rounding out the sound of the bass guitar. If the bass player used a pick throughout the track, sometimes the sound of the pick can be excessive. Try cutting the frequencies around 4kHz until the sound of the pick is less noticeable. To simply strengthen a weak bass, try a slight boost somewhere between 100-200Hz.

4. If your killer distorted guitar is overwhelming everything else in the mix, including the lead vocal, don't just turn down the level--that may cause you to lose all the power of the guitar in the mix. Instead, pan the guitar to the left or right so that other elements such as the vocal have enough room in the stereo spectrum. If it's the rhythm guitar you can dub a copy the guitar track to a spare track and pan one track hard left and one hard right. EQ each guitar track slightly differently. Then you can lower the levels a lot, and still have a powerful guitar track that doesn't overpower the other important material in the overall mix.

Recording With Effects: If You Gotta, You Gotta

5. How many of you have all the effects devices you could possibly use? Not one of you? I didn't think so. Not many of us can afford to buy separate effects processors for every track in a mix. The solution is called 'printing with effects', i.e. recording certain tracks to tape or disk with the effects selected and in-line with the original track. Just as you would normally record a guitar solo with your wah-wah pedal, try recording your solo with a flanger in-line. You may find you can record a better (or more creative) solo if you are in sync with the sweep of the flanger, and you can 'play into' the effect.

6. Try recording your lead vocal track with a reverb in place that seems to really bring the best out of the singer, due to the great boost that the reverb provides to the singer's confidence. Some people let the vocalist monitor the reverb vocals as they record the vocals dry, without reverb. That's great, but if you're going to be squeezed for effects processors later, try printing the vocal with the reverb. If you don't like it later however, you'll have no choice but to redo the part.

7. Another situation you can get the most out of your effects processors is in a MIDI/Tape or a MIDI/Hard Disk recording environment. Normally, MIDI tracks (keyboards, drum machines) are not recorded to tape; you'll record them into a MIDI sequencer and play them back in real time when mixing down. They are thus known as 'virtual tracks' for the very reason they do not physically exist as tracks on the multi-track recorder. However, when mixing, if you are short one reverb unit, and you happen to have one spare tape or hard disc track, you can record one of the virtual tracks (say, a snare drum) to the spare track with full effects. The nice part about this is if you mess up and find the effects too heavy-handed, you can simply erase the track and try again. Once you have the snare drum sounding great, you can mute the snare drum track in the sequencer, and use the reverb unit for another virtual instrument.

Studio Safety

8. One of the most common causes of electrical fires is the improper use of extension cords. If you've got a single, living-room quality extension cord running from the wall to all of your studio equipment, say, twelve to fifteen devices or more, please invest in a halogen fire extinguisher, which are specially designed to put out electrical fires.

9. In addition to buying the fire extinguisher (it will only set you back fifteen bucks or so), try to prevent a dangerous extension cord situation, buy investing in quality chords, rated at 15 amps or better. If you're the type of person that likes to daisy-chain power strips (I confess to this weakness), then make sure you buy the power strips with the built-in circuit breakers, which hopefully will trip in the case of a short in any device plugged into it. Try to avoid stretching or excessive bending in any of the AC wires in your studio, especially those coming from the wall or the power strips. If not, excessive heat may result and a fire is certainly possible; the idea here is to have the fire extinguisher handy, but never need to actually use it.

10. If any of your gear has internal fuses (power amplifiers, older synthesizers, speakers), use only the fuses recommended by the manufacturer. These devices have fuses for a reason; if there is a problem, believe me you are going to be happy you had the proper fuse in place, doing what it was intended to do--shut down the device. It is a good idea to have a spare fuse for each device in the studio that requires one. Otherwise a great session can be cut short by a blown fuse (and most hardware stores around my house are closed at 2 A.M.)

No More Bad Acoustics

11. Ideally, all home recording environments would be as quiet, non-reflective and 'in-tune' as a commercial facility. We all know that's not the case. A little acoustical treatment in the typical spare room or garage that serves as a home recording space can go a long way. To reduce reflections that might cause unwanted reverberation when monitoring, replace your reflective (hard and flat) wall surfaces with soft, absorptive areas. You can use commercial material like Sonex, or hang heavy drapes, it basically accomplishes the same thing.

12. Phase cancellation can occur in home studios with improper placement of monitor speakers. If speakers are located in the corners of your studio room, pronounced phase cancellation can occur due to the fact that short reflective paths (short distances between the wall and the sound) cause interference with the direct sound. If the speakers cannot be relocated, you might try treating the area around the speakers with absorptive material.

13. A common problem in home studios is the phenomenon of standing waves. Standing waves can easily occur in rooms with parallel walls (i.e. your basic square or rectangular spare room), as the walls reinforce a particular set of frequencies. The distance between reflective surfaces determines the frequency of the standing wave. Since the standing wave represents a boost in that frequency, you'll be tempted you cut that frequency out of your mix in order to get the correct tonal balance. Upon playback in another room, the results should point out a needless cut--blame it on that darn standing wave. Better yet, avoid the standing wave phenomenon by locating your studio in a room with non-parallel walls. Since I know you're not about to do that, I recommend making one of the parallel walls absorptive. Another idea is to use diffusers, which are wall treatments that have rounded or complex surfaces (i.e. pyramids, both two-sided and four-sided) that tend to reflect sound evenly throughout the room. The advantage of installing a diffusive surface material is that it will also help to eliminate dead spots in the room.

I'm planning to share a lot more tips for home studios in future columns. Please let me know your favorite tips and techniques for getting the most out of your home studio. And don't forget to join Guitar Nine's Home Studio Registry. The project you save -- may be your own.When I hear someone say they are going to go out and catch a good buzz, I know they're not headed for their home studio. Buzzes, hums, hiss, pops, crackles and other sonic debris are the bane of home and project studios everywhere. These undesirable noises have a number of distinct causes, and thankfully, most can be reduced or eliminated at the source of the problem. A few can only be controlled with suppression devices. We're going to look at some of the ways hums and buzzes can intrude on your studio and I'll give you some ideas for dealing with it.

Crossing Audio and AC Cables

A common source of hum is generated when audio cables are placed too close to AC cables, outlets and switches. This includes running audio cables too close to the wall, as AC cabling exists behind the walls to connect each outlet in the studio. AC cables, power strips and external power supplies are a primary source of hum, because they emit large magnetic fields that can be picked up quite easily. To combat this, audio cables are normally shielded with woven copper wires (screening wires) to deflect any stray electromagnetic fields that may be coming from AC power cables. However the screens are not perfect, and the effectiveness of the screening can vary with the quality of the audio cable and the connectors.

In order to reduce hum from this situation, it's very important to route your audio cables away from (i.e.. not touching) the AC cables from your gear, as well as power-hungry elements such as beefy power amplifiers and external power supplies. The rule of thumb is, when an audio cable has to cross the path of an AC cable, make sure it crosses at a right angle, which minimizes the pickup of this type of hum.

It's also possible you have a computer monitor, television, or guitar head amp generating some hum through a nearby audio cable. You can test for this by simply cutting the device off. If you find it's causing a problem, you'll have to route the cables a different way.

Also, don't skimp and buy the cheapest audio cables you can find. Look for cables with woven copper screening (not the inferior lapped variety), all-metal connectors, and use the shortest length of cable needed to connect two pieces of equipment. The shorter the cable length, the less probability of picking up AC interference.

Stacked and Racked

Stacking different pieces of equipment on top of each other, or racking them together without a gap, may cause a problem due to one unit's AC power transformer being located in a spot that induces hum in the other unit. You'll be able to detect this quickly when initially assembling your studio gear, but if your studio is already wired, try turning off equipment just around the unit that is humming. If the humming stops, you can move the unit that's causing the problem to another location.

Usually, equipment encased in steel provides maximum containment of magnetic fields, whereas plastic and aluminum cases provide almost none. If some of your gear is steel-cased and other units not, try to rearrange it so your plastic or aluminum-cased devices are adjacent to your steel-cased equipment. The other option is to leave a single-space gap in the rack between two pieces of gear. You only need to do this, however, if you know you have a problem.

Ground Loops

An even more common source of hum is the infamous ground loop, also known as an earth loop. In a lot of ways, they are the most tricky to chase down and solve. Once you've applied most of the common-sense measures to reduce hum, any hum remaining will usually be due to a ground loop. It's possible to completely eliminate ground loops if you take the necessary steps, but it involves a systematic process of eliminating problems one by one.

Ground loops occur because most modern equipment is fitted with three-prong AC plugs. The third prong on the plug connects the chassis of your gear to AC ground, which ensures that your body cannot become the ground path for AC current. However when two pieces of equipment both have three-prong plugs and are connected together with cable, the shielding on the cable is also responsible for grounding, and a ground loop is possible. This is because if a piece of gear has two paths to ground (one, through it's own AC cable; two, through the audio cable connected to another unit, and through that unit's AC cable) a loop of current is formed that can act like an antenna, through which hum can be induced. You can even pick up radio interference this way.

Most ground loop problems can be solved by plugging all of your studio gear into a single grounded AC outlet. But by doing this, it's possible to overload the AC outlet, so you've got to be sure the AC source is properly rated to handle all the gear you have plugged into it.

The only way of being sure you have a potential ground loop problem is to listen carefully for a slightly edgy hum as you are assembling, wiring and cabling your system. If you have your gear powered up as you are monitoring for hum after each audio connection, you can quickly determine the source of the problem. Move the unit that seems to be causing the problem and try it again. You won't have to worry about battery operated gear or gear with two-prong adapters, as they do not contribute to ground loop problems.

Some people solve ground loop problems by using a ground lifter (three-prong to two-prong adapter) on one of the units, thus breaking the AC ground and severing the loop. I have to stress that this is a very dangerous option that should not be used, because you're giving up the safety factor that the AC ground wire provides. Again, if you choose to use 3- to 2-prong AC adapters, electrocution may result.

The best (but more expensive) way to fix a persistent ground loop problem is through the use of a transformer. The job of the transformer is to ensure there is no electrical contact between two pieces of equipment, except for the audio signal. Transformers have no ground connection between the input and output connections, thus effectively breaking a ground loop.

When buying transformers for ground loop problems, it's important to realize that the more inexpensive variety may color the sound a bit due to frequency response irregularities. Good engineering and construction quality costs!

A company called Ebtech makes a relatively inexpensive transformer isolation box called the Hum Eliminator, which is two transformers in a single metal case. As of May, 1997, it sells for around seventy dollars. It may serve you well to have one around to diagnose ground loop situations. Ebtech also makes an 8-channel version for about $250. There are other companies such as Jensen Transformers that manufacture more high-end units.

Bad Power Supplies

If you've inserted transformers between two devices and you still hear hum, it's possible the power supply on the output device has gone bad. There's no way to be sure of this unless the power supply is external and you happen to have a second power supply handy. The only way to cure a problem like this is to have the power supply checked by a technician.

Bad or Improperly Wired Cables

Sometimes the audio cables themselves introduce hums and buzzes, due to defective shielding. You can check for this quickly by simply swapping cables. In addition, you wouldn't be the first person to connect an output to an output, or an input to an input, so get a good flashlight and take ten seconds to make sure you've got your equipment hooked up correctly.

Short-Burst Edgy Buzzes

If you hear a buzz that only appears for a short time and at a constant level, you may have a pulse in your AC lines, which can be caused by the switching action of fluorescent lighting, dimmer switches, window air conditioners, or a refrigerator turning on and off. The best situation is to locate your studio in a room without these items. If you must share an AC circuit with of these elements, you're going to have to install a proprietary noise suppressed AC distribution panel, which will give you a clean power supply for your studio.

When All Else Fails

The ideal solution for your humming and buzzing situation is to correct it using one of the methods above. There is no substitute for checking for these problems as you hook up and wire your studio from the ground up. It may even be worth disassembling the whole studio and starting over, checking each device as it's connected to verify the 'cleanliness' of the system as a whole.

If you really can't solve your problems any other way, it may be time to consider an audio solution to surgically remove the offensive sounds. Remember though, this is simply treating the symptoms of the problem, and you're avoiding the root cause of the problem altogether.

In the past, parametric equalizers were used to lessen the effect of hum in the mix. To remove a noticeable AC hum, you would simply set your equalizer to 60Hz, which is the frequency of AC hum, and notch out the sound with a very narrow bandwidth. However, surrounding bass frequencies would almost certainly be affected.

Today, you've got units like the Roland SN-700 Noise/Hum Eliminator, which claims to "...easily remove AC line hum, dimmer buzz, fluorescent lighting, hum, ground loop noise, fan noise, tape hiss, SMPTE bleed and more." Of course the same caveats apply to a device like this as with the parametric equalizer--you may experience a coloration of the overall sound, which may or may not be a problem for you.

Finally, you can try using a noise gate, set to gate at low levels so that background signals such as humming and buzzing are eliminated in quiet sections of the audio. The down side is that you may be removing quiet sections of your music as well. Also, when the gate is not set properly, it can be very obvious when it is finally engaged, making the hum more obvious. If you have to use a gate, try to limit its use to a single channel or two instead of the entire mix, so it's side effects are not as easily noticed.

Dan McAvinchey is a guitarist and composer living in Raleigh, NC.

He believes every musician or composer has the power to write, record and release their own music.

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