A wireless system always consists of two parts. The transmitter stays with you, connects to your microphone and sends the signal out into the air using radio waves. The receiver is located near and connected to your amp. There are many types of wireless systems available to us. As a rule, you usually get what you pay for. But there are some practical considerations.

Some wireless transformers are small and physically connect to your mic, making a single self-contained unit. Others need a cable that connects to a “belt pack.” The belt pack systems are often of very good quality and fairly economical, but they have a drawback in that you cannot simply put your mic down and move away. Because I double on saxophone in my band, I need to switch instruments quickly and so I have to be able to just lay the mic down. Some belt-pack users will simply shove the mic in their pocket – if this is okay with you don’t rule out belt pack systems. Of the self-contained systems, there are two flavors – the “guitar bug” is a device designed for (guess what) an electric guitar. It has a 1/4″ plug on it – and can be used with a high impedance mic with a 1/4″ jack. An example of this is the AKG WMS40 Guitar Bug system. The other flavor is designed to plug into the end of a vocal mic. It therefore has an XLR connector and expects to be plugged into a low impedance microphone. A good example of this kind of system is the Samson CR77 with AX1 transmitter. There is no tonal difference due to the impedance alone – you simply have to choose the system that works with your gear.

Just about every manufacturer in the market offers a belt pack wireless system. Shure and Sennheiser are popular, high quality brands. Self-contained systems are harder to find but are available from AKG, Samson and others.

Important to users in the United States: Under FCC rules, anyone who uses a wireless microphone that operates in the 700 MHz Band, and that means almost every wireless system sold prior to late 2009, should not be operating it. All users of 700 MHz Band wireless microphones (and similar devices)—including theaters, churches, schools, conference centers, theme parks, and musicians—will need to retune (where possible) or replace their wireless microphone equipment with other microphone devices. For further information, please visit the FCC website.

And so ends our series on harmonica microphones. Our thanks go to Murray Hunter for plugging in the original concept. To Keith Shackleton for sorting out the feedback. And, of course, Greg Heumann without whom none of the content would have been audible in the first place. Now get out there and create your own reverb.

Greg Heumann is the curator of our Harmonica Microphones section. Read his previous articles here. You can find more from him at www.blowsmeaway.com.

Feedback is that awful loud screeching, humming and/or whistling sound a system makes when a microphone picks up the sound from the amplifier’s speaker and sends it back to the amplifier for further amplification. Every system (in this case a microphone plus amplifier) has a feedback threshold. Turn the volume up loud enough and feedback occurs. Keep the volume below that point and it doesn’t. Unfortunately we often need to have our volume very close to the feedback threshold in order to be loud enough, and so feedback can come and go as conditions change. But some setups are less prone to feedback than others, and some microphones are less prone than others.

Factors influencing feedback are:

1. Gain of the amplifier
2. Distance of microphone from speaker (amplifier or PA, house or monitors)
3. Tone settings
4. Player technique
5. Directionality of microphone
6. Sensitivity of the microphone

What can be done about feedback?

Believe it or not, microphone choice is not very important. Many players believe one microphone is more sensitive to feedback than another, only because that microphone is louder/hotter/more sensitive than another. The only “fair” way to judge one mic vs. another is to adjust the amplifier’s volume so that the sound out of the speakers is equally loud from mic A to mic B, and then see which one more readily produces feedback.

Vocal mics and instrument mics are designed to be “directional” – to pick up more sound from the front than from the sides or the rear, specifically to help avoid feedback on stage. So a well designed microphone can help with a feedback problem – but only when it is in free air – in a rack or on a stand, and not in your hands. Once you pick up a microphone and cup it, all bets are off. If you hand hold a mic, feedback will be more of an issue because the mic is moving around and facing different directions. When you move your “cup” away from your face, it can act like a satellite dish and can catch and reflect more sound to the mic than if it was in truly free air. Your hands also destroy a good deal of the directionality designed into the mic. Many players learn to manage this by pressing the face of the mic against their chest while not playing. Ideally, you should be set up just a little further from “the hairy edge” of feedback so it isn’t too difficult to manage.

When you play acoustically, you can help to control feedback by ensuring that little to none of your sound is coming through the monitors. Depending on the frequency of the feedback, equalization (tone control) can help as well. When you’re playing amplified, all of the above applies. However the gain of your amplifier is the most important variable in taming a specific system. A microphone is designed specifically to pick up sound waves from the air, so it is a much more sensitive and troublesome feedback device than a guitar string. Consequently guitar amplifiers (and most harp amps start out as guitar amps) are set up with much more gain than we need. This allows the guitar player to get Hendrix-like feedback when he or she wants it, but it can be a nightmare for a harp player.

A change of mic might give you, at best, 1-2 dB more volume before feedback. A change of amp might be good for 10-15 dB, or even more.

Reducing feedback by reducing gain – amplifier tube substitution

Generally you can’t adjust the gain of a solid state amplifier. However we can usually substitute lower gain tubes for higher gain ones in a tube amp’s preamp section – and this can instantly make an amp more harp friendly. The most popular preamp tunes are the 12A# series. A typical Fender guitar amp has three tubes in the pre-amp section, and all are 12AX7′s as the amp comes from the factory, set up for electric guitar. Here are the gain factors of the 12AX7 and its compatible cousins:

GAIN FACTOR 100: 12AX7 – aka ECC83, 7025, ECC803, E83CC, 6681
GAIN FACTOR 70: 5751
GAIN FACTOR 60: 12AT7 – aka ECC81, 6201, 6679
GAIN FACTOR 45: 12AY7 – aka 6072
GAIN FACTOR 41: 12AV7 – aka 5965
GAIN FACTOR 19: 12AU7 – aka ECC82, 5963, 5814, 6189

As you can see, three 12AX7′s creates a huge amount of gain. On an amp like this, you will likely not get the “normal” channel volume past 2 before feedback. If your amp has an “overdrive” channel it will be completely unusable. There are way too many combinations and permutations to describe here, but here is one recipe for success: On a Fender Bassman type amp with three preamp tubes, replace the two 12AX7′s closer to the amp’s center with 12AU7′s. This should make a significant difference. If it isn’t enough, replace the outer one with a 12AT7 or 5751. You should now be right in the ball park and grasp the concept – continue to experiment and pick what you like.

Although reducing the gain of your amp makes it more manageable, it will not perform miracles. A Fender Blues Jr. sounds ear-splittingly loud in your living room. Yet you get on stage at a jam and wonder why it can’t be heard. So you turn it up until it is feeding back and conclude that you have a feedback problem. But you don’t. You have an amplifier problem.

Get a bigger amp!

More power helps, but I’ll let you in on a little secret. More speakers is just as important, or more so. Compare the surface area of the speakers on different amps. A Blues Jr. is a 15 watt amp with a single 12” speaker – if you do your maths you’ll know it has 113 sq. in. of speaker surface area. My Sonny Jr. Cruncher is about 35 watts, and has a 12” and two 8” speakers. That’s 213.5 sq. in of speaker surface area – more than twice as much power and almost twice as much speaker area. But even that isn’t always loud enough at some of the jams I go to. I can get the volume on that amp to 9 with no feedback. If I want to be heard at a jam, I bring out the big guns. My Sonny Jr. Super Sonny amp has about 50 watts, and has four 10 inch speakers (here’s Sugar Ray Norcia using one to fine effect). A little more power, but another big jump in speaker surface area – 314 sq. inches to be exact. The difference is huge. Room filling volume, and again, no feedback!

Other feedback management tips

Avoid “overdrive” amplifier channels or pedals: generally speaking these work by adding lots of gain and will be feedback nightmares. If you’re using a PA system and your amplifier is mic’d, tell the sound guy to take you out of the monitors completely. If you can’t hear yourself on stage, and getting closer to (or further from) your amp doesn’t help, have him sneak a tiny bit back in. Change where you stand. Turn the treble or mid-range down. Use an “anti-feedback” pedal. If none of that cures your feedback problem, you are simply asking more of your amp than it can deliver. The bigger the amp and the more speakers it has, the more likely it is that you can get good volume before feedback, regardless of which mic you choose!

Volume controls

And finally, get a volume control! There is nothing worse than getting everything all set during sound check, and then encountering feedback during your performance. But this happens all the time, because room conditions change for a variety of reasons (the sound man included). You certainly don’t want to have to dive for your amp to adjust it, knowing the feedback problem will be worse when you get closer. A volume control at the mic is the perfect solution to this problem. You can instantly kill feedback from where you stand just by lowering the volume a bit. When you perform, you often can’t be sure where the feedback is coming from, and a volume control tells you whether it is you or not.

Volume controls are useful tools even if feedback isn’t an issue. Although any good player has good dynamic control over his instrument, there can still be a wider dynamic range in your playing and with the band than you can accommodate merely by playing softer. Being able to back the volume off right at the mic is really nice when you’re comping behind a quiet passage in the music. You can also use a volume control to explore the tonal range of your amp, when otherwise you’d be firmly in feedback territory. An amp turned up to 10, with the mic’s volume controlled by you to remain below the feedback threshold, will sound different than the same amp at 6 with the volume control on the mic all the way up.

Some players pooh-pooh volume controls. Don’t listen to them. Practically every pro player I have seen uses a volume control. Charlie Musselwhite, Kim Wilson, Rod Piazza, Jason Ricci, Rob Paparozzi, Billy Branch, Curtis Salgado, Mark Hummel… the list just keeps on going. All of them use volume controls.

Feeling tied to the stage by your mic lead? We have the solution: for our last article in this series, we’ll be talking about going ‘wireless’.

Greg Heumann is curating our Harmonica Microphones section. Read his previous articles here. You can find more from him at www.blowsmeaway.com.

The microphones we are talking about in this series of articles are referred to as either “high impedance” or “low impedance.” In general, a vintage bullet mic is a high impedance device and a modern vocal mic is a low impedance one. This is not always the case, however.

So we should find out what kind of microphone we are holding in our hand (the general rule above and a quick Google should reveal all). Once we know that, the following facts hold true:

1. Microphones and amplifiers work best with certain load or drive levels, respectively. We want to optimize the power transfer from mic to amplifier. For this reason, it is desirable to choose a microphone with an impedance that equals the impedance of the device it is connected to – an amp, a foot pedal, a wireless transmitter, a mixer, or what have you. Ideally we plug a low impedance mic into a low impedance input, or a high impedance mic into a high impedance input. If we can’t acheive this, there is an alternative…
2. We can use an impedance matching transformer: a simple device that can “match” (or adjust) a low impedance mic to a high impedance load, or vice versa.
3. Low impedance systems were developed after high impedance ones, and were designed to enable much longer cable runs and better reject noise (like hum) that is picked up by the cable.
4. There’s no difference between low impedance and high impedance microphones if you are looking to improve your tone and get better resistance to feedback. Merely switching from one kind of microphone to the other will not guarantee improvement.
5. Low impedance systems are almost always wired with XLR jacks and plugs. This is a worldwide industry standard.
6. Many different kinds of connectors are used for high impedance devices, including XLR. However when XLR is used, the cable-to-pin wiring is not the same as it is for low impedance XLR. Mixing low- and high-impedance cables and mics just because you can connect them together with XLR can lead to poor performance. When you see a 1/4″ jack or plug (like guitar players use) it’s a safe bet that you’re looking at a high impedance device. The same is true for the “screw-on” connector that was made by Switchcraft and Amphenol, which was found on many vintage mics and is still produced today.
7. There’s nothing wrong with connecting a high impedance mic with an XLR connector to a high impedance load (like an amp) with a cable that has XLR at one end and a 1/4″ connector at the other. There is something wrong, however, with using that same cable to connect a low impedance mic to the amp – because there is an impedance mismatch. In this case a proper low impedance (XLR to XLR) cable should be used, together with an impedance matching transformer.

Technical note: By definition, impedance is “a measure of the opposition to the flow of alternating current through a circuit” , that current being the signal from your mic, which in loose terms is an electrical picture of the sound going into it. POWER in electrical terms is the rate at which electrical energy is fed into or taken from a device or system. You can have the same amount of power with low voltage and high current, or high voltage and low current. Low impedance mics have a signal with more volts and less current; high impedance mics are the reverse.

Now we’re all matched up and our power transfer is optimal… SKREEEK, SKRONNK! Uh oh, feedback. If you’re a harp player with a microphone, chances are you’ve heard that awful sound. Next time around, we’ll tell you why it happens and how to manage it.

Greg Heumann is curating our Harmonica Microphones section. Read his previous articles here. You can find more from him at www.blowsmeaway.com.

Last time around, we described two kinds of elements used for amplified blues harp – dynamic and crystal elements. So let’s name some of the most sought-after crystal and dynamic elements, and find out how to shop around for them.

Which are the most desirable Dynamic elements?

The most desirable dynamic elements among amplified players are the vintage Shure “Controlled Magnetic” and “Controlled Reluctance” elements (“CM” and “CR”). Yes, CR’s and CM’s are dynamic elements – but because they are special ones we usually refer to them by their marketing names instead of just lumping them in with all the other “plain old” dynamic elements. These elements came in the Shure 520 and 520D microphones, among others. The current 520DX has a more modern dynamic element which is less desirable tone-wise. It is brighter and has less bottom end.

Much has been written about Shure’s Bullet elements; Dave Kott’s excellent site has more information than you’ll ever need so I won’t repeat it here. Suffice it to say that these are great elements, and because of their “magnet and coil” construction, they have tended to last much better than crystals. Many players are still using the dynamic elements from vintage Electro-Voice microphones as well.

Dynamic elements are the most common among modern microphones as well. They are used in the majority of mics marketed to amplified harp players (Shure 520DX, Peavey Cherry Bomb, Bushman Torpedo, etc.) as well as the most popular instrument and vocal mics like the Shure SM57 and SM58. There is a huge range of dynamic elements. The newer they are, the more likely they are to appeal to acoustic players and the less they will to amplified players. This is because they have extended high frequency response which can be harsh and they don’t tend to “break up” as easily, making it harder to induce distortion at the amp. However there are exceptions. The Shure SM57, for example, actually breaks up very nicely and makes an excellent harp mic.

Which are the most desirable Crystal elements?

The most desirable crystal elements craved by harp players are the Brush Crystal, the Shure 99-131 aka “R7” element that came in the Shure 707, and the Astatic MC-151 element that came in the JT30. The Brush and Shure elements are all but extinct. The MC-151 element was made for a much longer period of time, but has still been out of production for many years. They are available (I still collect them for my customers) but their prices are going through the roof.

Over time, any crystal absorbs moisture and softens until it literally falls apart. If you buy an “untested” crystal on eBay, it is practically guaranteed not to work. Often, if you shake them they rattle. This is what is left of the crystal bouncing around inside the element. Along the way, they become more and more susceptible to damage from drops, temperature extremes, or even very aggressive playing (I once ruined a crystal, which undoubtedly was getting ready to go anyway, by drawing really hard with a tight cup. The vacuum pulled too hard on the diaphragm, and broke the connection to the crystal).

How do I get one?

Ah the million dollar question. If you like to gamble, you buy them on eBay. If you don’t, buy them only from a reputable dealer who knows harp and knows elements. eBay is filled with deception and ignorance. If you see a crystal element available (usually in a mic shell) with a description that says “I have no way to test it” you can assume it is dead. Of course this isn’t always the case, but it is generally true. Crystals don’t always fail all the way at once. Their output can simply get lower and lower. So even one that “works” may not work well at all. The only way to know is to try an element by hooking it to an amp. And the only way to know then whether it is in truly great shape is to know how loud they’re supposed to be. I buy crystal elements to provide to my customers. I charge a high price for them. Why? Because I’ve had to eat the cost of a lot of lousy elements I will not resell. If you buy from me, you get a good element, or your money back!

You’ll often see eBay vendors showing you the resistance measured across an element. However, you should never hook an ohm meter to a crystal – you can damage the crystal this way. But across a dynamic element, the fact the resistance is neither zero ohms (a short) or infinite (open) tells you that the coil in the element is still working. The value will also tell you something about the element’s impedance. 50-100 ohms indicates a low impedance element, somewhere around 1000 ohms indicates a high impedance element, and somewhere in between can indicate a medium impedance element. These are rare, but should be avoided as it is difficult to find a proper impedance-matching transformer for them.

The ohm meter’s reading, however, will not tell you anything about the tone of a particular element. Do not believe that 1.1K ohms is better than 1.2K ohms, or vice versa – it simply isn’t true. It is also not proof that the element is good. An element that’s corroded or squashed may not work or will work poorly, even if the coil is OK.

If all this talk of impedance leaves you just a little bit in the dark, don’t worry. I’ll explain more in our next article.

Greg Heumann is curating our Harmonica Microphones section. Read his previous articles here. You can find more from him at www.blowsmeaway.com.

There are many kinds of elements in all of microphone-dom, including ribbon mics, condensers, electret, crystal and dynamic. Acoustic players may well use any of these. However, except in the recording studio, amplified players will only be concerned with dynamic and crystal elements.

Fact 1: There is no such thing as a mic element designed for harmonica players.
Every microphone uses an element that was designed for more general purposes. As a rule, the more expensive a mic was when new, relative to other mics of its vintage, the better it performs as a general purpose mic. To engineers, this means it has better frequency response (able to “hear” higher and lower sounds), flatter frequency response (no particular frequencies are made significantly louder or softer), and/or more “headroom” (the ability to tolerate higher sound pressure levels without distorting).

In this case “better” is usually means better for acoustic players. But…

Fact 2: For amplified, bluesy ballsy tone, “better” is worse.
Although low-end frequency response is good, harps simply don’t make any fundamental notes that are way down in the bass range. All the bass is added by the amplifier through harmonic distortion. And too much high frequency response can sound harsh, even hurt people’s ears. The reason vintage bullets are so popular is that their frequency response typically falls off at as low as 3000 Hz – even though some humans can hear as high as 20,000 Hz.

Fact 3: High headroom also works against us.
It prevents us from overdriving the microphone. The Audix Fireball, marketed as a good harp mic, has the most headroom of any mic I’ve played – 140dB according the spec. And it is a good harp mic for playing acoustically, or for avoiding a distorted input signal for other reasons such as playing through an amp modeling pedal. But the difference in tone between cupped and uncupped with this mic is far less than it is with an “older tech” microphone. In the case of amplified tone, older and cheaper is often better.

The venerable Shure Green Bullet and the Astatic JT30 are prized by harp players – because they give us that “old-school” sound. They are, in many cases, what our harmonica heroes used. Do you know why they chose them in the first place? Because they were cheap, even when they were new! The JT30 was the entry-level microphone in Astatic’s line, and came on the market at a price of about $6.

Dynamic and crystal: what’s the difference?
In my next post I’ll be talking more about vintage dynamic elements made by Shure: “Controlled Reluctance” and “Controlled Magnetic” elements (“CR” and “CM”). Both crystals and CRs/CMs have a great tone for amplified blues. It is hard to describe the difference, but to me a good crystal has a slightly nasal “honk” to it that the CR or CM doesn’t have. CR/CM elements have more bottom-end and can sound a little fatter and richer. The only way to know is to try good examples of each.

However, there are some other important factors to consider. Crystals have a lot going against them. The good ones were made 70 years ago and are at the end of their life. Many have died, most are dying, and a single drop can kill a good one. They are also extremely high-impedance elements. This means a low-impedance connection will dramatically reduce their tone. Just as turning on all the electric stuff in your car makes the engine work a little harder to keep turning the alternator, lowering the resistance across the mic’s terminals is like dragging your foot on the brake. Not only does the total output drop, but the frequency response changes too.

For this reason some custom harp amps are made with a 5 megohm input specifically for crystals. An amp with 50K input impedance will suck the tone right out of the best crystal. Anything you add between the mic and the amp, such as a volume control or a long cable, can lower the impedance as well. A good amp and good volume control will still let you get good tone, but you have to be aware that this is an issue and manage it. Finally, if your amp hums when you connect a cable that has no mic at the end, you can expect hum when you connect a crystal-element mic. A dynamic element may well reduce or even mute the hum.

Dynamic elements (including vintage ones) are practically bulletproof. They have lasted well all these years, so they are less expensive and more plentiful. Their impedance is lower so they stand up well to volume controls, pedals, splitters, etc. (Ultimately though, if the input impedance drops too far you will suck tone from any element.) And you can drop them (protected, of course, by a proper gasket inside a microphone shell) and they don’t break!

How do they actually work?
A dynamic element uses the electromagnetic principle to convert sound into electrical energy. A diaphragm is an extremely thin membrane that vibrates in response to sound waves. The diaphragm in a dynamic mic either directly moves a coil around a fixed magnet, or moves a pin which in turn moves inside a coil. Either way, the movement generates an alternating electrical current. A dynamic microphone and a speaker are almost identical in principle. With the speaker, you take electric energy and convert it into sound by sending the current through a coil, which then wants to move relative to a fixed magnet. The speaker cone is attached to the coil. Voila – sound! A microphone is the reverse – you take sound energy and turn it into electrical energy by moving a coil past a magnet. A speaker can actually be used as a microphone, and a dynamic microphone can be used as a speaker (think headphone speaker.) Please don’t experiment with your good harp mic elements to see how well they work as speakers. They don’t work well, and the risk of your damaging them is very high.

A crystal element relies on an entirely different principle called the “piezoelectric” principle – the diaphragm is connected to a crystal of “rochelle salt” or a manmade ceramic with piezoelectric properties. Mechanically deflecting the crystal generates an electric current. The lighter on your gas barbecue uses a crystal too. You press down on a button which mechanically bends and “snaps” a crystal (without breaking it) and with no battery required, a spark is generated. Crystal elements are rarely made these days, although they can be made incredibly cheaply so they still exist for entry level applications and are found in some production microphones. The new ones, unfortunately, don’t have the tone of the older ones – and the older ones are becoming very expensive.

Keep an eye open for the second half of Greg’s post on elements, where he names some of the most sought-after crystal and dynamic elements, and explains how to shop around for one.

Greg Heumann is curating our Harmonica Microphones section. You can find more from him at www.blowsmeaway.com.

Good amplified tone starts with the player’s tone, and is accentuated by microphone technique. Cupping is an art; a learned skill that is neither obvious nor easy in practice. Properly done at its extreme, no air you suck or blow can escape “the seal” and therefore no sound at all comes out of the harp. Your goal is to visualize that all your breath must enter and exit through the microphone itself. In reality it is very hard to do this, and it is hard to even come close at first.

When the seal with a microphone is very good, the air pressure changes are effectively “coupled” to the microphone’s diaphragm in a way that is very, very different from the normal “free air” mode in which mics were designed to operate. The result is a very distorted signal sent to the amp.Note that to accomplish such a seal, you must not only create an airtight seal between the rear of your harp and the microphone, you must also seal off the open holes on the front of the harp – otherwise the air you blow/suck is free to travel under the coverplates, through all the open reeds and out/in the other open holes on the harp. This reduces the “coupling” effect you’re shooting for. You can learn the technique acoustically before ever attempting it amplified.

First, listen to the technique applied acoustically:

And now, the same technique amplified:

However to choose a good harp mic, you must understand what cupping is, as different microphones will respond in dramatically different ways to the technique.

Why are some mics more responsive to cupping?
Factor 1: Mic shape and size. When a mic’s physical shape or size makes it hard to achieve a good seal, the effect of cupping will be less.

Factor 2: Headroom. When a mic has a lot of “headroom”, which is the amount of sound pressure it can handle before it distorts, it will obviously distort less. A perfect example of this is the Audix Fireball, which has something like 140dB of headroom. A brilliant feat of engineering, but it makes almost no difference to your tone whether it is cupped or not.

So how does microphone shape make a difference?
There are literally hundreds, if not thousands of different kinds of microphones to choose from. Mics vary in cost, size, purpose, tone, and shape – all of which affect us. For amplified tone, one of the most important variables is the mic’s shape.

There is little about the shape that affects the mic’s tone in free air. However everything about its shape affects your ability to cup it easily and effectively. People’s hands and muscles differ, so one size most definitely does not fit all.

A stick mic with a ball end like the SM58 can also be difficult for smaller hands. The smallest diameter stick mics, like Shure’s SM57, are easy for some to cup, yet cause hand cramps for others. And their length gives the weight of the cable leverage to pull down on the end of the mic – another fatigue factor. (The weight and length of Shure stick mics was one of problems I set out to solve when I developed the Ultimate Series Microphones.)

The largest diameter bullet in popular use is the current model of Shure’s Green Bullet, called the 520DX. It is hard for people to cup well unless they have fairly large hands. It is also one of the heaviest mics available – and when you perform a three- or four-hour show, hand fatigue is a factor worthy of your consideration.

Finally, some mics like the popular JT30 or Hohner Blues Blaster have bumps around the circumference that make tight cupping very uncomfortable. Among vintage bullet mics, there are many shells that are a little smaller. The Electro-Voice 630 and M23/43, the Astatic T3, the Shure 707 are all excellent shell choices and are popular among “do it yourselfers” as mic project starting points.

Another variable is where the mic’s shell places the element relative your harp. Some shapes will hold the element further forward, others further back. Further forward reduces the size of the air cavity between harp and element, reducing the tonal changes from cupping. This effect is slight but real.

In summary, a mic’s shape makes a real difference! You’ll have to experiment to find what works best for you.

Watch out for Greg’s next post, with everything you need to know about microphone elements.

Greg Heumann is curating our Harmonica Mics blog. You can find more from him at www.blowsmeaway.com.

Choosing a microphone: Acoustic vs Amplified?

In choosing a microphone, the most important question of all is “What do you want to sound like?”

There are two classes of sound, with infinite variety in each class. If you’re a classical musician, you’ll probably stand in front of a stand-mounted microphone and you want the amplified sound to cleanly reflect the tone of your playing – giving the closest representation of what it would be like to be in the same room with you, with no microphone or amplifier at all. We call this kind of sound “acoustic” even though it may in fact be picked up with a microphone.

When I talk about acoustic playing, I do not mean “not amplified”. I do mean, however, that the microphone is in free air – that is, on a rack or a stand, and not in your hands.

If you’re a blues musician, you might want the fatter, more distorted sound that is so prevalent in the genre. We call this style “amplified” style as opposed to “acoustic”. (Hey, I didn’t write the rules – sorry if it’s confusing!) In this case the microphone is almost always hand-held. Jazz, country, bluegrass and other styles often find themselves between these two extremes.

Acoustic tone
Acoustic amplification is straightforward and can be effectively done with modern, relatively inexpensive gear. A standard vocal mic like Shure’s venerable SM58, plugged straight into the PA, is a safe bet and usually sufficient. Lapel mics, which are usually of the “electret condenser” type can also be used, although most harp players prefer a dynamic or ribbon mic for acoustic playing.

Good acoustic tone is largely a function of the player’s tone in the first place, so for now I’m not going to talk about acoustic microphones specifically.

However, one essential piece of wisdom is that your distance from the microphone makes a huge difference in volume. It is, unfortunately, rather easy to hurt people’s ears when you walk up to an acoustic mic that is set up for someone to sing through at a distance of 6 inches, and you play loud harp right up against it, or worse, pick it up and cup it. The secret to good acoustic tone through a microphone is to learn to play quietly! If you sing and play through the same mic, a volume control on the microphone is a very useful tool.

Where does “amplified tone” come from?
To understand the amplified sound, we need to talk about the interaction between the player, the amp and the mic. Where does that big fat gritty sound come from? It comes from a combination of your technique, the microphone, and an amplifier’s tendency to add distortion in the form of manufactured notes (related to, but not the note or notes you’re playing). These notes are called “harmonics.” This distortion can occur simply because the amplifier itself is operating beyond its “clean” volume range, but as players we have control over the degree to which it occurs by our own technique and microphone choice.

We can overdrive the microphone, through our own playing volume and more importantly through a technique called “cupping”, so that it sends a distorted signal to the amplifier. The amplifier responds by amplifying that distortion and more readily adding its own. Of course, amplifiers vary a great deal in the degree to which they add harmonics, and in the quality of that sound. So let me just say a word about amps…

Amplifiers – Tubes vs. Transistors?
An important characteristic of tube amplifiers is that they tend to produce “even ordered harmonics” and “analog clipping” when they distort. These can be pleasing to the ear. Solid state amplifiers tend to produce “odd ordered” harmonics and “square wave” clipping when they distort. These can be very harsh. As a rule, either kind of amp played cleanly/acoustically will sound fine. But overdriving a solid state amp, such as any modern PA, or some modern guitar amplifiers, usually results in harsh sound. There are exceptions to the rule, but that’s the subject of an entirely different article! However, a very important advantage of the tube amplifier is our ability to manage feedback through tube substitution to lower the amp’s gain. More on that later.

Watch out for Greg’s next post on the mechanics of cupping.

Greg Heumann is curating our Harmonica Mics blog. You can find more from him at www.blowsmeaway.com.