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#21: Symetrix Review – Using External Processing

By | February 18, 2007

External ProcessorsWelcome to another edition of The Podcasting Blog where we talk about everything podcasting, from audio recording to syndication and just about everything else. If it has to do with podcasting, chances are we’re gonna talk about it. This week we’ll look at the Symetrix 528E which is a voice processor, we’ll talk about external processing and in the news I’ve got some results in from the Corporate Podcasting Summit. I’m your host, Ken Walker, you’ll hear all this and more in this week’s episode of The Podcasting Blog.


Our main topic this week is on external processing, so I thought it would be a good idea to do a review on some external processing equipment and the newest toy that I have here in the studio is the Symetrix 528E. It’s basically a compressor, but it actually does a little more than that.

To start off, it’ll take up 1 space in a rack and you get an XLR jack that’s phantom powered. That means you can hook your mic right up to it, and it gives you a decent mic preamp. It features a series of processors, the first of which is a De-Esser. Well, actually the very first thing is an input gain which lets you adjust the volume of the input signal. But the first real processor is the De-esser. What this does, is help take the edge off of those high sibilance sounds like ssssss and shhhhh. A De-esser is basically a compressor that works only on a band of frequencies. So within a certain range, a high range, it will limit the signal to help keep those sounds from becoming harsh. It’s a subtle effect but it does help, and with the 528E you can adjust the frequency band that is attacked, as well as how much the signal is compressed. You can also turn the effect off or on.

Next in line is a downward expander and a compressor. These two work together and they do a pretty good job. They’re both turned off and on together, but if you want you can adjust them so that only one is actually processing audio.

The downward expander is a big time saver for me. It’s almost like a noise gate and for those of you that don’t know what a noise gate is, it’s a device that lets you set a level of loudness that as long as the signal that a mic is picking up stays below that level, no audio is passed. OK, so if, for example, you have it set to -30dB and there is a noise in the room like a computer fan, but the noise is at a constant -35dB, then it’ll be as though the fan isn’t on because the noise gate will stay shut. As soon as you talk into the mic and go over -30dB, then the gate is opened and ALL the audio picked up by the mic will pass through.
Now that does NOT mean that it masks out the PC fan or whatever other noise is in the background. It only means that as long as the noise is below the threshold that you set, nothing will pass through. Once the gate is opened, everything passes through. The thought here is that the signal level of what your trying to record should be much louder than the noise, so if the noise is only heard when you’re actually speaking, it shouldn’t be too bad, and generally that’s true.

The downward expander isn’t exactly a noise gate, but it works in much the same way. You set a threshold and any sounds below that threshold get compressed, they get squashed down to where they’re almost nothing. Then as soon as you start talking, and again we’re dealing directly with podcasting here, as soon as you start talking, the downward expansion isn’t going on any more and the full signal passes through the processor.

Where this really saves you is if you have some background noise, or occasional background noise. You can set the threshold to just above that noise and while you’re recording, it’ll seem like everything is totally quiet. Then when you talk, your voice pretty much overpowers the background noise. Obviously this doesn’t work for very loud sounds, it’s only meant to help with little problems.

On the other extreme we have the compressor. This takes loud sounds, which would typically be you, and compresses them down or squashes them down by a predetermined amount. This helps your volume levels to stay pretty constant even if you were to get very excited and all of a sudden get a little louder. It also helps keep your signal from over modulating and getting distorted. You don’t have to fool with attack and release because the 528E is designed for voice so those values are factory set. The only three knobs for this area of the unit are the threshold for the downward expander, the threshold for the compressor, and the compression ratio which is basically how much compression you want on the signal. Again, there’s a switch that turns both the expander and the compressor off or on, but you could operate them independently if you wanted to just by adjusting the threshold levels either extreme minimum or extreme maximum.

The next section gives you a three band EQ and all three bands are sweepable, meaning you can adjust the frequency that is affected. So there’s some engineering jargon for you this week, sweepable means that you can adjust the frequency. What I mean by that is, most stereos have maybe a two band EQ, treble and bass, or maybe they have a 5 band graphic equalizer with 5 different frequencies that you can adjust. In either case though, all the frequencies are preset. The bass might be set to around 200Hz or the treble might be 5000Hz, they’re all preset and all you can adjust is the amount of gain that is added or cut from the frequency. With a home stereo, a 5 band EQ might be OK, but if you want to really work your voice and get something that makes you shine, it’s good to be able to pick what frequencies are worked on. People are all different and different settings have to be used. What works for a man probably won’t work for a woman.

So with this 3 band EQ, you can adjust the frequency that gets affected, then you can adjust how wide of a band is affected, in other words, how many adjacent frequencies are also affected, and you can either enhance that frequency, or detract from it. You’ve got a button to turn the whole EQ section off or on.

One kinda neat thing is that all of the effects have inserts in the back and you can actually re-route the order that they are processed in. For example, let’s say you wanted to do the compression first, then the de-esser, then the EQ. Also, you can run another processor into the chain by sending the signal from the de-esser stage to your other processor, and then back into the compression stage, just as an example.

At the very end of the chain is an output gain that lets you get your signal up or cut it down to fit whatever your recording device is.

So those are the features, but how does it perform? Well, we use it here in the Podcasting Blog studio and to sum it all up, I like it a lot. Everything works and it works good. The compression is almost unnoticeable. The EQ helps you give your voice a little thickness and clarity, and the downward expansion is indispensible for studio work when you don’t have a $50,000 studio. Just the downward expander saves me time in post production work because I don’t have to go through and remove ambient noise. The compressor saves me time because I don’t have to go through and level my volumes.

Symetrix is pretty high-end gear and you’ll find these processors in radio stations all over the country. Expect to pay about $500 for one. It’s not the cheapest upgrade you can get, but just so you know what kind of difference it makes, I’ll shut all its features off and let you hear for yourself.

OK, now everything is off and this is basically what things sound like. It’s a little noisier, the volumes aren’t the best, and the voice sounds pretty flat. The S’s are also a little sharper. Now let’s turn the de-esser back on and you’ll notice a slight change in sibilant sounds, not a lot, but enough to take the edge off. Now we’ll turn the downward expander and compressor back on. You’ll hear it got much quieter right? And now we’ll kick in the EQ which will give us a bit better definition. The Symetrix 528E.

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Let’s talk about external processors and why you might want to use them in your podcast. Lemme start with this. Podcasters are not all radio engineers. Just like a lot of radio talk show hosts aren’t engineers. They know something about a topic, and they want to share that knowledge, or talk about those kinds of problems, whatever, but they have an engineer that knows audio. Most podcasters though can’t afford an engineer, and really, you probably don’t need one if you have the right gear and know what to do with it and how to use it. That’s what we’re all about here, one of the purposes of this podcast is to make you sound like a 50,000 watt radio station, if at all possible, without you having to hire an engineer.

The reason that I said all that is that I come from a music and production background. I play guitar and piano and I’ve done a lot of recording, I’ve been around it all my life. That made the transition to podcasting very easy for me because of my technical background. I’ve also been working as a computer geek for about 15 years starting out as a bench tech and then as a network admin and now a software instructor. So from the technical side of things, this was all pretty easy for me and very natural, but that’s not the case for everybody and what you’ll find out on the net, is a lot of people that could produce a good podcast, as far as content, but they’re pretty clueless on the technical side.

That’s where we wanna fit in and help out, either by producing your podcast for you, or by helping you have the knowledge to do it yourself. Somebody might say “Ken, that doesn’t make sense. How can you have a business doing podcasts for people, and at the same time turn around and tell them how to do it themselves?” The answer is simple. Not everybody has the time or resources to do a podcast themselves. I’ll tell you everything that’s involved in doing it right, and you decide if you wanna try it yourself. I hope that with these podcasts I’m gonna help somebody out there and they’ll do a great job. I wanna educate business owners about how effective podcasts are, how much they can help their site, and I wanna help the hobbyist that wants to podcast about breeding rabbits.

Honestly, I didn’t mean to ramble on about that so much, so let’s get back to the topic here, external processing. What is external processing? You’ve got your mic, and your audio capture device, whatever it is, and then we’ve got the computer. After our audio gets recorded, we can process it with effects and plug-ins. Those are little software programs that DO something to our audio signal. We could add reverb, we could normalize it or amplify it, all of which is done after the signal has been recorded.

Well, if we use external processing, we’re essentially doing all of that processing AS the recording is being made. So for example, I could have an effects processor that adds reverb, or compresses my signal. The difference is, the processing is done between my mic and my audio capture device, and it gets recorded like that.

Right away I’m gonna say that some people prefer to record perfectly dry, meaning absolutely no effects, and then do all the processing later on. For some things, that’s OK I suppose, but it won’t take you long to realize that having a compressor on during your recording will save you lots of time in editing later. Especially, imagine that you always record totally dry, with no processing, then you always go in and run the same compression plugin with the same settings. Then you always run the same normalization with the same settings. All of that will take time, and you always get the same result. So why not use an external compressor to do it and get the same results every time, without having to run the plug-ins?

Now, plug-ins aren’t bad, I use them myself. They give you access to equipment that you might not have the money to buy, or you don’t use often enough to justify it, especially if you’re not a full time podcaster or musician. One thing you can’t do with a plug-in though is hear what things will sound like WHILE you’re recording. For example, you put your headphones on and you start recording. You’ve got your compressor on, your noise gate, some EQ maybe a sonic maximize, even a little reverb if you want, but you’ll hear it exactly like it’s getting recorded.

There are two reasons that people just use plug-ins. The first is cost, and hey, if you don’t wanna spend the money or you can’t afford it, don’t buy it. The second argument is that they want the dry signal alone and then they can do with it what they want.

This argument works for some things, but mostly way out effects. If you’re always using the same plug-in with the same settings, do it externally and save yourself the time. For me, if I can save myself 10 minutes per podcast, then I’ll make back the cost of my equipment pretty quick.

External processing is done in series which means that your mic plugs into the first device, usually a mic preamp and compressor, and then the output of that device will go to the input of another device and it will continue like that until it gets to your audio capture device. Now, in practice, you’re probably gonna have one or two devices in your signal chain. Like maybe a preamp and compressor and an equalizer. For podcasting that’s about all you need.

This week’s review featured the Symetrix 528E which has pretty much everything that a podcaster would need for voice processing in one nice little package. If you get something like this you can plug your mic into it and then plug the output into your audio capture device. You could also go out and buy a mic preamp, a compressor, a noise gate, and a parametric EQ. In that case you’d daisy chain all of those devices and then finally go to your PC.

Now those of you that aren’t real serious about podcasting, or you just don’t wanna spend the money, you don’t have to. You can get a lot of good results from plug-ins, I personally think external processors sound better, but that’s just my opinion. Get a good quality mic and a good audio capture card and you can make some great podcasts with plug-ins.

Again, for podcasting, the big tickets are compression and EQ, probably some type of noise gate or downward expander too.

This week’s news comes from the UK but I think if we had a similar study done in the US we’d see similar results. Figures from Edison Media Research suggest the audience for podcasting is on the rise, and that general awareness of the medium is growing rapidly.

The stats, which were originally presented at the Corporate Podcasting Summit in London, show that awareness of podcasting grew by 70%, while actual use increased by only 18%.

The audience for podcasts is up by 18% from a year ago. In 2006, 11% of those surveyed listened to audio podcasts; in 2007, the number was 13%

Podcast awareness has grown in the last year, from 22% to 37%

Video podcast use is up by 10%, from 10% to 11%
The podcast audience:

49% are female, 51% male. Age distribution is relatively even also, with more 55+ listeners than in the 18-24 age group

Podcast users are twice as likely to have incomes over $100,000 and nearly twice as likely to have incomes between $75,000 and $100,000

Podcast users were 36% more likely than others to have made online purchases, and 4 times as likely to have purchased songs online

Podcast users spend 50% more time online

Podcast advertising has been predicted to grow from $80m in 2006 to $400m in 2011. This makes sense when you look at the relatively high incomes of podcast users, and the fact that they are more likely to make online purchases.

The stats come from a poll of 1,855 telephone interviews in January 2007. A study by the Pew Internet and American Life Project last November put the US podcast audience at 12%.

Recent UK figures suggested that 8% of the UK population has downloaded a podcast.

That’s it for another episode of The Podcasting Blog, I’m Ken Walker and I hope you’ve enjoyed the show. Next week we’re gonna take a look at promoting your podcast and I’ll let you know some details on getting your podcast into iTunes and some other directories. If you’d like to ask a question or comment on the show, you’ve got two options. My email address is podcasting@seocompany.ca, or you can just post a comment on the blog. I’ll see you back here next week, same time, same place.

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