Category: engineering

The Obfuscation of Electronics: The Behringer Xenyx 502

Hits: 27

This is more like a meta-review. I have gone to Canada Computes where nearly the entire Behringer line is sold, and was impressed by the specs. But does it do what I want, the way I want it?

I face a number of obstacles, being a fuddy-duddy former college DJ. For one thing many of the commonplace terms have changed, obfuscating what I think they’re saying, versus the actual intent when I purchase the stuff and find out for myself. It’s a Wittgenstein thing. Sussing out the exigetical intent of the interface, even as explained by the user manual available online, is an essay in near-futility only to be appreciated by interpreters of ancient Hebrew texts or Egyptian hieroglyphs. That is, knowing the words on the labels and diagrams isn’t enough: what is the meaning?

Watching the audio reviewers on You Tube try and tackle this interface (and there were a surprising number of them, and we’re only talking about this particular product, the Xenyx 502, made by Behringer) revealed a litany of awkward hesitations and skipping of knobs and jacks they knew nothing about. This was even true of the professional reviews. The YouTube review on the Behringer site, done by a kid who looks and acts not a day older than 15, is an embarassment and should be taken down. The only good parts occured when he was reading from the manual.

Indeed, what do they mean? And I am going beyond the obvious: no-one needs to tell me about the function of the phone pot or the main mix pot; I think I can figure out the RCA ins and outs on the middle right of the unit; nor about the LED level meter; nor about the balance or panorama (Pan) settings. I also managed to figure out that the PA-system style mike connectors are called XLR connectors. That’s that 3-pin jack on the top lefto corner of the photo. Then there are 8 of what used to be called “quarter-inch jacks” across the top of the unit, but are today called TRS jacks (for tip/ring/sleeve). Fair enough.

But what puzzles me to no end is the TRS jack just below the XLR jack. This is where the exegiesis comes in, and all that Wittgenstein stuff. And the reason it drives me crazy is because, really, I don’t have XLR plugs on my microphones. Instead, I have a pair of mikes with TRS plugs. These plugs are the most common in existence. We even used quarter-inch plugs when I worked as a college DJ. XLRs were something you hooked up to a PA system at your local school. XLRs often suffered from not being sealed all that well, resulting in a low-frequency electronic “buzz” that would have made them unsuitable for recording.

On one of the You Tube demos, a guy on the video (HobbitAssassin08) says that the “Line In” for Channel 1 (that is the TRS jack in question) can be used with TRS-style mikes with their own battery (and therefore have no need for the “phantom power” feature that Behrninger brags about). This is almost perfect. However, my mikes (TRS in my case probably means Tandy/Radio Shack, with the requisite quarter inch mono jacks) have no power of their own. They are basic professional mikes with a magnet and a diaphragm, which produces the current and the signal for my voice. It needs an amp or a recorder to process the signal. The specs say the mixer jack has a minimum of 10,000 ohms impedance. My mike is rated at 500 ohms (30% tolerance — depends on the frequency).

The power supply is proprietary. Also, channel 1 only works with line or mike inputs but not both. The other four channels are part of two stereo channels. If you plug a source into the left channel only, you get mono.  5 channels in, 3 out: the three are for two separate stereo outputs and one headphone output. The whole mixer board is slightly larger than your hand.

Will I buy it? That’s the question that has been driving me batty this past week. Looks like this mixer board is not compatable with my existing mics, and that I will have to purchase yet another mike or a pair of them if I am to buy this one. Looks like I will have to look elsewhere for a mixer board.

Microphones Part 2: The war of silence

Hits: 14

With the levels down so low, my test recording needed post-processing. I used Adobe Audition 1.5. In most of these audio-doctoring softwares, all you need to do is to normalize the levels, so that “0” is the highest your levels should go. Audition had a “Normalize” setting, and of course that also boosted the background and electronic noise, along with my voice.

Now I needed noise reduction. Adobe has a fancy dancy noise reduction interface which is useable for the brave of heart. The main idea is to highlight “silence” (a moment of pure background noise) somewhere on your waveform, in order for Adobe to get a snapshot of the frequencies that need to be attenuated with the noise reduction. When I tried it, the noise was virtually eliminated when there was only noise, especially at the start, but the noise seems to have a reverberation, since if the noise is at the end, it fades in a stepwise fashion. The noise in the middle is reduced substantially, but not enough to compare with other noise reduction that I know about, like Dolby or ANRS. DBX would have been good, if they could have licensed it.

Audacity won the war of silence, in making the background noise pretty much inaudible, with its noise reduction scheme, which had a far simpler interface. The noise reduction was equally effective in the silent bits and the parts with talking. I used the same strategy in giving it a sample of pure background noise to its noise reduction profile. I found that only the very lowest setting on their “Less/More” slider would not make me sound like I’m living in a tin can, or even disappear altogether.

To be fair, I was using Audition 1.5, against the latest version of Audacity. I hear that Audition is somewhere around version 3.0. But I am happy with Audacity, since Adobe charges a pretty penny for its sound editing software.

OK, So I am trying to build a home theatre with a quad-core system box …

Hits: 14

And part of such a home theatre would consist of a way to hook up the Bravia I bought on sale to the mainboard, which has HDMI on it. My strategy was to enjoy both cable and “free” internet television through either the keyboard or the remote device. So, then there was the TV Tuner card I had to configure. Windows Media Center said that my card “could not be configured in Canada”. I phone the retailer who sold me the card, and indeed they too found to their horror that it could not be configured with Windows Media. I was instructed to send it back and get a replacement.

I think I am an unfortunate victim of “trade barriers”. Perhaps some CRTC regulation is preventing Windows from allowing this card to work, so by law, Windows is telling me that it is a criminal offense to configure my card.

I check out the card, and it is from AverMedia, a comapny based in Taipei, Taiwan. Well, what competition is left in Canada if Chinese-made TV tuner cards are left out? There are a host of brands provided by Happauge (based in Long Island last I heard), but I think that is it for any major brands. Yes, if you’re Canadian, you buy either American or Chinese. Since you can’t buy Chinese, it’s American or nothing. Not that I expect there to be any Canadian brands, but, I am suprised to see a lack of any European brands at the stores I visited.

Maybe it’s nice to hear once in a while that the Chinese are not given too much of an easy ride in our economy. But this time, I got burned by that idea.

Version 2 of the TI Nspire operating system

Hits: 38

My main complaint about the Nspire and Nspire CAS, the need to have some kind of input statement in its programmnig language, looks like it is closer to reality. I just have to fiddle with it some more to see if it can really place data in tables (or now, spreadsheets), and see if I can really do I/O in a running program as was the case for the TI-84 family. To be clear, I am not using the new “touchpad” version of the CAS, I am using the slightly older version, which had the original keyboard.

When I did a test statement

Request "---> ", j
and ran it, the calculator came back with a screen using “–>” as a prompt, and a blank for me to input something. I entered “36”, then the input window disappeared, then the string

--> 36
was output. The input window seems cumbersome.  That could be because I like command line input, and think it has less memory overhead on a device where every byte of RAM is precious.

At any rate, the value is stored in j, and this was proven by doing the multiplication

4j
and I got 144. This was on a calculator whose memory was cleared due to the OS upgrade. The cursor is much more sensitive, and there is a noticeable speed impovement over prior OS versions.

I tried to make a simple program, and got nowhere with the Request statement, when I placed it inside a FOR/END FOR loop in a named program.

Rube-Goldberg Machines V

Hits: 16

Another one. A couple of years ago, this was a Honda Accord commercial, and it caused quite a sensation when it got released. It took over 606 takes and cost over 6 million dollars to make. Any minor misfirings resulted in having to set everything up from scratch, all over again. It was a 2-minute ad spot which was released in the UK in 2006.

%d bloggers like this: