Saturday, August 21, 2010

The Difference a Preamp Makes

Or to put it another way: Making a free internal sound card record like a $150 sound card.

This blog post is about achieving good audio recording as cheaply as possible, so I'm going to kick it off with an audio file so you can actually hear the difference that I'm talking about.

Here's the story.
I don't use a headset to talk to people on the computer; those things are uncomfortable and the audio quality sucks.

For the longest time I used a dynamic mic (which was the Shure PG58), attached to a tripod stand, and the mic plugs into my Sound Blaster Audigy 2 ZS Platinum, which has a 1/4 TRS jack socket and a built-in preamp which did a great job at recording my voice (compared to the headset). Over the many years I've used it to record video tutorials and recently I've been using that microphone constantly on Skype writing for Hackberry Hollow.

A few weeks ago I bought a new computer. The computer that I've been using (the one that was bought to power the Touch the Table project) started to die. And actually my timing was impeccable because 4 days after I built my new computer the old computer died completely, forcing me to move all my work over to the new computer.

But I wasn't going to move my Audigy over to my new computer. So what's the problem?

Creative Labs went down the tubes.
The reason why that's a problem is because A) the sound card is really old and has already been in 2 computers so far, so it's probably going to kick the bucket soon anyway, B) a while back I noticed that their most recent drivers were more annoying to use and were also more buggy, so I ended up installing the old drivers I had on the CD instead, and C) there was the Daniel_K incident from two years back. (The short version is that Creative Lab's Phil O’Shaughnessy admitted that their company intentionally crippled its Vista drivers as a business strategy, Daniel_K modded the drivers so they would work in Vista, and then Creative Labs went after the modder), and since I'm trying to get an Audigy to run on Windows 7, that could be an even bigger problem. Yes, it's possible that they've gotten their act together since then, however I haven't heard anyone recommend Creative Lab cards recently. I suppose the point is that I'd rather not risk put my trust in a company to have good driver support on 64-bit Windows 7 for hardware that is seven years old.

Why not get a new sound card, like an M-Audio one for example?
I've been a big fan of M-Audio's products. They are great for multi-track recording (very good actually), but their cards are specialized for music production and don't have some of the consumer-grade features I was wanting. For example there's no green, black and orange 3.5 mm TRS jacks for surround sound speakers, or even headphone jacks for that matter (it is expected that you have a mixer and are using speakers to monitor your sound).

I can use one sound card for recording and another for playback, but having two soundcards on a computer can be a big pain. Music production software has no problem with it, but in the past I've had big problems with your normal everyday Windows programs sending sound to the wrong device, even when the default device is set properly.

Also, since I've decided a year ago that I won't pick up music composition for a while (maybe when I retire as an artist/writer), a pro M-Audio sound card is not on my priority list. However I do want to record good clean sound because I still do video tutorials and the occasional podcast, and of course I use Skype all the time, so having crisp sound would help there too.

What about USB microphones?

I've been impressed with the USB microphones actually, even though I originally scoffed at the concept. The Samson mics are pretty good, but I need to monitor my voice as I talk because I do occasionally wear headphones—those big headphones that cup around your ears and are affectionately refereed to as cans. I need to be able to hear my voice through the headphones when recording videos and podcasts to make sure I'm not breathing into the mic, that the volumes is right, and to shut out noises that could otherwise be coming out of my speakers.

The problem with wearing these kinds of headphones is that they are so big and comfy they block out all other sound that is not coming from your headphones, including your own voice. If you'd like to know why that is a problem, talk with your hands pressed against your ears, and that's what it sounds like when you talk wearing those headphones. It is surprisingly hard to talk if you can't year your own voice.

Monitoring your voice with a USB mic may not be possible, and you can't have any latency (sound delay) because that's more annoying than not being able to hear my voice at all. I will note that the Samson G Track USB microphone does have a headphone jack for no-latency monitoring that addresses that issue, but it does have another issue that I'll get into later.

Since I'm the A/V guy for Animation Nation it would be nice to have a microphone that doesn't have to be plugged into a computer to work. So a USB mic was out.

Plus they are more expensive than normal mics because they are basically a condenser mic and USB audio interface in one.

So I still needed to come up with a solution for my picky recording needs.

The solution: buy a preamp.
Simple, right? The core problem with plugging a microphone into your computer (or anything else for that matter) is that you need a preamp to amplify the sound being recorded from your mic. You know how you have to turn on the 10 dB boost for your headset microphone to work? In the case of a nicer microphone like mine, even a 30 dB boost isn't enough. However, with a preamp you don't have to do that; it'll be full power like plugging your MP3 player into your computer or car using the line-in jack; the audio comes in loud and clean.

After reading some reviews on Zzounds (which is the best online store ever for music/audio gear) I picked the M-Audio AudioBuddy preamp because it hardly introduces any noise into the signal, it's a brand that I trust, and was the best bang-for-your-buck selling for $60. If nothing else I can still use the preamp for Animation Nation Night, allowing me to add a second microphone to our speaker system.

I got it in the mail, plugged it in, and heard the results. Here's what was stunning. There wasn't any audible background noise. Where did it go? I could have sworn I could always hear the noise that—I assumed—was from the fans in my computer running in the background. Maybe it was the new mic? I tried my old one. Same thing. No background noise.

I had some recordings from video tutorials that I used to compare my Audigy with its preamp, and the internal Realtek soundcard with the new M-Audio external preamp. The difference was night and day. My internal Realtek sound card, the one that is integrated into the motherboard, the sound card that I got for free sounded better than my Audigy, a $200 sound card (which I also got for free but that's another story). And the preamp has the added benifit of letting me quickly mute my microphone by pushing the power button on the preamp.

So as it turns out my Audigy's preamp wasn't very good at all, and the recording quality with the integrated Realtek cards isn't bad provided that you don't use their 10-30 dB boost option either.

Adapter plugs and the mic only coming in the left channel.
This will be pretty obvious when you do this, but you'll need an adapter to plug the microphone into your computer. Microphones generally have an XLR connector, and many microphones come with a free XLR to 1/4 TS cable (1/4 TS is the standard cable used for audio equipment, like mixers and amps.)  So you'll need to get a 1/4 TS (mono) female to 3.5 mm TRS (stereo) male adapter so you can plug that into the microphone port on your computer. The one I bought was the Hosa Technology GMP-386.

I just happened to have had a 1/4 TRS (stereo) to 3.5 mm TRS (stereo) adapter lying around, so I used that initially. It worked but when I was monitoring my voice it was only coming out of the left speaker. (This is also a problem with the Samson G Track USB microphone, and since it uses a USB connector you can't fix the problem with an adapter. Yet another reason why I decided not to get a USB mic.) The one-channel issue is a little annoying to work with. It doesn't interfer with voice communication (like Skype, etc.) but it does when I monitor my voice, and can be a pain during audio editing if I recorded a track in stereo. So that's why I got the mono to stereo version of that adapter (and a mono to mono one as well just to see what would happen, and that adapter gave the same unsatisfactory left-channel-only results).

The drawback with the mono to stereo adapter is that the volume gets cut (per channel) because it's splitting the signal strength between the two channels, which makes sense of course. In my experiments however, recording mono tracks in my software brings both channels together to the original signal strength anyway, so in the end it's not a problem.

If you want to record great quality sound on that integrated Realtek sound card, all you need is a $60 preamp, a $60 microphone (or that $130 Audix OM3 that I just bought, which only has slightly better sound quality because it's not as bassy as the Shure PG58), and that will let you record some great quality voice work with it.

I will add though that getting a sound card, like the M-audio one, should have a much better signal to noise ratio over the Realtek sound card. So if you are serious (and I'm not that serious), the M-Audio cards are probably always the better option, and you won't have to buy an external preamp (which in total would only cost $60 more or so).