Be sure to check in with Harvey in his PSW RecPit Forum.

Over the years, I've heard people tell me a lot of things that they believe to be true, but aren't. They hear it from other musicians and pass it on and pretty soon, people start accepting it as absolute fact. The actual truth gets buried in history and that's the way legends are born. It's charming, but inaccurate. Let's examine some of these beliefs.

Bass drum ports: There are a lot of drummers that cut a small hole (usually around 4 to 6 inches in diameter) in their front head to "port" their drum. Somebody may have told them that this tunes the drum (like a bass reflex speaker) to improve the bottom end. Is it true? Yes and no.

Cutting a hole will provide a vent which can be tuned to resonate the air inside the drum, but that's what the second head does anyway - it's like a passive radiator, driven from the pedal head. Putting a hole in the front head is kinda like putting a hole in your speaker to port your hi-fi system.

So, why do drummers put that hole in their drums? Primarily to use as an opening for a kick drum mic, without removing the head entirely. A lot of drummers still print the band's name on their drum head and that's important to them. That hole is important when you walk into a studio to record. Live drummers saw their studio counterparts using the hole and thought it looked cool, and adopted it.

Where the hole is located is very important, but not for any reason you'd normally think about. It should be above the center line of the drum, so that a short mic stand will work, and the mic stand boom arm angle will let the engineer position the mic to point directly at the spot where the beater hits the head.

The hole diameter should be around 6 inches to allow for various size microphones. The center of the hole should be above the center line of the drum, so that the entire opening is in the upper half of the drum. Any 6 inches opening above the 9:00 to 3:00 line will work.

Tubes are better than transistors: When transistors first appeared, their distortion characteristics were very different than tubes. Once you exceeded their output range, they simply gave up, all at once and distortion went straight up very quickly. A transistor amp which hit 100 watts at .05 distortion might put out 110 watts, but at 35 percent distortion. A tube amp distorted slower and more gracefully, often generating 2nd and 4th harmonics - which made the sound even better.

The newer breed of MOSFET transistors were able to mimic this kind of distortion, and the gap narrowed. With the new breed of computer modeling amps, and some of the new DSP chips, the gap between tubes and transistors is getting even narrower.

Tubes are noisier than transistors: Nope, it depends on the circuit. You can build ultra-low noise tube circuits if you're willing to take the time to do it right. And let's get rid of the tubes won't reproduce high frequencies myth too. For many years, tubes ruled the high frequency roost in the megaHertz range. The main advantage to transistors over tubes is less heat, less susceptible to shock and vibration, and now, lower cost.

There's no difference in cables and cords: Somewhat true for speaker cables, once you get past the teeny size wires. Not as true for guitar and audio cables. Bad shielding, high capacitance, and poor construction can seriously degrade your sound in any cable carrying low level signals. There are now even some wire companies selling "directional cable," which is pure bull. All just hype.

Different batteries sound different: Hmmm. Some people swear they can hear a difference in batteries. I remain sceptical of their claim. Some batteries DO put out more current then other batteries and that MIGHT change the sound but I think different batteries of the same actual voltage and peak current output should sound the same. The jury is still unconvinced on this one.

A condenser mic is the best kind of mic: Best for what? If that was really true, they would use nothing but condenser mics in major studios. They don't. EVERY studio has dynamic mics, like the Shure SM 57, the AKG D112, the Sennheiser 421, and usually several ribbon mics and a wide assortment of general purpose mics. Why? Because there is no such thing as the ONE perfect mic for everything.

For big ballads, it's hard to beat the sound of a great big diaphragm condenser mic like the old Neumann U47, which now sells for around $10,000 in primo shape. But even that mic occasionally gets beat out by a Shure 58 or an old ribbon mic for some voices or some songs. A good engineer doesn't go by price - he/she will pick whatever works best for that particular sound.

PA amplifier wattage should match PA speaker wattage: Usually you can double the wattage of the power amplifier to prevent clipping. But if you're going to be playing loud, invest in a good stereo compressor to go across the output of the mixer to prevent huge spikes from blowing the speakers.

Guitar amps and speakers: 4 ohms, 8 ohms, or 16 ohms; is one impedance better than the others? Impedance is simply the working load the speakers put across the amplifier's output terminals. Maximum safe power transfer occurs when the amplifier is correctly matched to the speaker load. On stage, multiple speakers will give you more output, compared to a single speaker and provide increased power handling, but that isn't important in the studio. Many of the big groups use a little 15 watt amp with a single speaker to record.

Speakers can be wired in many different combinations so that is why many amplifiers have impedance switches on the back of the head. Which impedance is best? Any of them will work fine as long as the head impedance is set correctly - it depends on the speaker configuration you're using.

Electric bass - how low does it really go? The main output of a bass E string is primarily around 84Hz, not the 42Hz most bass players imagine. The reason is simple; the string length is too short to produce much fundamental. Yes, it produces some 42Hz, but most of the sound is an octave above that.

Which brings up the next question; how do you get more bass out of a system? It's very simple - you need to move more air. Low bass must move more air, so the answer is more power (to make the speakers you have move further), more speakers (so that each speaker doesn't have to move as much), or a more efficient ported or horn-loaded cabinet (so that the port and/or horn adds more air motion).

Find out more about Harvey and Indian Trail Studios at http://www.itrstudio.com, and be sure to visit his Rec Pit Forum.