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Archive for the 'Technical' Category

The Ol’ Spit-N-Shine

Monday, January 1st, 2007

If you have been listening to AD Radio since the beginning, you have (hopefully) noticed much improvement in the quality of the show, both in content and fidelity. This post will focus on upcoming technical improvements.

About a month ago, we took a major leap forward in sound quality when we purchased two new Heil PR-40 microphones. Compared to our old microphones– CAD GXL-2400– these new microphones are more accurate, more durable, and more user-friendly. Jaime and I are pleased with the improvements that has resulted.

In the next two weeks, we’ll be making many minor improvements to the audio quality of the show. Each of these improvements will be small and mostly undetectable, but that doesn’t mean they are insignificant.

The Monitor

The first improvement is a new monitor for Jaime’s computer. Her old 17″ CRT has some problems: the whole screen flickers, and there is discoloration and general waviness in one of the corners. Beyond that, the monitor itself throws off tons of interference. It creates so much interference that Jaime has had to sit with her microphone as far from her monitor as possible while we do the show in order to minimize the amount of interference picked up by the microphone. It is an energy hog, taking 100 watts of power.

A brand new Samsung 940bx flatscreen LCD is on the way for Jaime, sending her failing CRT to the graveyard. This is a really nice monitor made by a good brand. It has a very nice panel in it, and it comes with a highly adjustable stand (if you don’t have an LCD that rotates, you don’t know what you’re missing). It comes with a three-year warranty, and uses 60% less energy than the CRT.

The best part, though, is that it shouldn’t create the same interference as Jaime’s CRT monitor. I’ve got a nice 19″ flatscreen LCD, and I don’t experience any of the problems that Jaime’s monitor has created. We won’t have to hear the buzz from her old monitor. Even at 6 feet away, Jaime’s old monitor caused a 3-decibel buzz in her microphone that was later amplified during the compression stage. She will be able to sit at her desk and use her computer during the show, which is obviously very useful while we are on the air.

It will also allow Jaime to face away from me during the show. As it stands right now, our microphones were almost in a straight line from one another, about six feet apart. When Jaime would talk, it would be picked up on my microphone as well as hers. To combat this, aggressive downward expansion of my own mic chain was used. That aggressive downward expansion impacted the quality of my signal.

The Shockmounts

Our new microphones, with the vast improvements they provide, did not come with one key accessory: a shockmount. It’s kind of odd, considering that the new microphones cost about four times as much as the old microphones. In the context of the microphones’ competition with in the marketplace, it makes sense. But, that is neither here nor there. The microphones didn’t come with shockmounts.

Shockmounts help to isolate the physical connection between the microphone and the microphone stand. Elastic bands are used to suspend the microphone within the mount. It sounds simple, but they are very important. Without shockmounts, any typing, mouse use, microphone adjustments, or bumping of the desk is picked up directly by the microphone. These bangs and creaks and pops sound terrible, and shockmounts work to reduce or eliminate them.

The Windscreens

There seems to be a lot of varying opinion on windscreen usage or pop filter usage. Windscreens come in two basic flavors: open-celled foam that slips over the microphone itself and makes physical contact with the microphone, or thin materials that sit between the microphone and the sound source– either nylon suspended in a hoop, or very thin metal with tiny holes all over the surface.

The idea with a windscreen or a pop filter is that they block moving air from directly contacting the microphone element. When used in a broadcast situation, they mainly control the dreaded popping P. Popping Ps, or plosives, sound absolutely terrible. They are to be avoided if possible.

When you look through images of professional radio broadcast studios, you will find that most hosts seem to prefer either no windscreen at all, or foam windscreens. Very few hosts seem to use nylon windscreens, and even fewer hosts seem to prefer metal windscreens.

There are two issues with windscreens. The first is that, because they physically sit between the sound source and the microphone, they undoubtedly filter out some of the frequencies coming from the source, usually high frequencies from what I understand. The second issue, more with the nylon or metal windscreens, is that they can create phasing issues. I’m not going to go into the nitty-gritty details of what phasing is and how it impacts the tone coming from the source, but I will say that “noise reducing headphones” utilize reverse phasing to cancel out unwanted frequencies. In this case, reverse phasing causes cancellation of some frequencies, and that is obviously not a good thing.

So for AD Radio, I have decided that we will use foam windscreens. We have been doing the show without windscreens. We have had quite a few plosives that would most likely have been prevented with windscreens. I chose foam over nylon or metal mainly because foam is easier to use, and nylon or metal and the mounts that support them weigh a ton. Foam slips on the microphone while the metal or nylon windscreens are connected to a hard-to-position flexible shaft that never seems to stay in one place.

The Rewire

We use a lot of cables. I count at least 25 cables, with a running length over 200 feet, and containing individual wires totaling well over 1,000 feet. It’s quite amazing, really.

But, it was also put together on a very, very tight budget. It was assembled without the benefit of nearly a year’s worth of knowledge and research that I have done into broadcasting and audio equipment. In short, it was done wrong. Of course, it has been getting the job done. But still, wrong.

There are two types of cable that can be used to connect the equipment: balanced and unbalanced. We are currently using balanced cables for our microphones, but unbalanced cables for everything else. The different is sort of complex, but here goes. Unbalanced cables use two wires: a ground and a signal. Balanced cables use three wires: two signals and a ground. The two signals are sent out of phase from one another. When the signal reaches the final destination, any noise in the signal is removed, the phase is flipped on the out-of-phase signal wire, and what remains is a very clean signal. Obviously, balanced is better.

Converting the setup over to balanced cabling requires replacing just about every cable we are currently using. Unfortunately, cables are not cheap– especially good ones. I priced our cabling needs at over $300.

Instead of sinking $300 we don’t have into a bunch of cables, I have decided to build my own. I’ve got 147 feet of high-quality bulk cable on the way, along with 30 different connectors of various types. With a soldering iron and an evening, I will be able to convert our setup to mostly-balanced for under half of the original estimate.

I don’t know if the difference will be noticeable or not, but I have a feeling that it will.

Ferrite Cores

Ferrite beads are the big cylinders that you find at the end of some cables, like your monitor cables. They help reduce RFI (radio-frequency interference) and EMI (electromagnetic interference). I’m not sure if they are going to make a big difference in our setup or not, but I was able to get 50 of them for under $20 delivered, so they are worth a shot.

The End

So, there we have it. All of these improvements will be implemented within two weeks. More specifically, everything will be in place before the January 3, 2007 show except the rewire. The rewire will be complete by the January 10, 2007 show.

It’s going to be a lot of work, but it should pay off in the end. I expect that in the next two weeks, AD Radio will sound a lot more like a professional radio broadcast. And from a technical aspect, that is the goal.


New toy has arrived.

Thursday, September 14th, 2006

Well, the new toy for the broadcast has arrived.

I went through and made a sound sample so you can check it out:

Let me know what you think!


New Toy on the Way

Friday, September 8th, 2006


I purchased a new toy for the radio show yesterday, and it should be on the way shortly. It will make its debut on either September 13th or September 20th, depending on when it arrives.

Here it is: Behringer Virtualizer Pro DSP2024P.

What will it do? Well, it will allow a variety of special effects. Reverb (for that in-a-cave sound), Delay (for that in-a-canyon sound), Lofi (for the megaphone/airline captian sound), Pitch shifter (for the satan sound), and a bunch more.

It’s going to be a lot of fun. I can’t wait!