Microphone & Audio Series (2) – Compressor & Mixer Basics

So you have wisely chosen your microphone of choice. Now all we have to do is get it connected to the computer and start recording right? No. Not necessarily. Unless the microphone is a USB mic (which are usually plug and play), your going to want to have control over your audio dynamics before it hits the computer. In other words, you want to be able to process your audio on the fly so the listener is receiving the best quality possible. Before your vocals reach the computer and then the listener ears, you want to make sure that it is of the best quality possible.

There are two VERY IMPORTANT pieces of hardware that help control and tweak the dynamics of audio. The two devices are a compressor and a mixer. You’re probably asking yourself, “Why in the world would I need that”. You see just having a microphone is like taking an instance of sound and throwing it out there. When we communicate via speech our vocal volume fluctuates. If we don’t need EQ mixers and Compressors strapped to the side of our ears, then why do we need them in recording?

Believe it or not, your ears actually do have it’s own internal compact compression system. You have three sections to your ear (Outer, Middle, and Inner). The outer section is what we normally see. It’s the flappy pieces of flesh on each side of your head. There is a connected passageway that leads down to the ear drum. This picks up the sound. The inner part of the ear functions like a transducers. It converts the vibrations.

So where does the natural compression come in at? When incoming sound becomes “too loud” (eg. Concert), the muscles around the three bones tightens up altering the normal functionality of natural sound processing as well as the level entering the ear. A compressor does exactly what it names suggests. It compresses sound. Why do we need compressors in recording/broadcasting? So the audio that you are hearing can be relayed at a consistent level while maintaining the difference of normal and loud.

Think about it. At the beginning of a song, a singers vocal volume usually starts off soft and subtle. As the song reaches it’s climax the singers voice reaches louder volume. However, even when a singer is practically screaming into the mic while maintaining a note, the overall volume does not sound louder in volume as any other part of the song. This is because a compressor is keeping those very loud decibels at a specified level. Dynamic control is a very important key to acquiring GREAT audio quality in recording and broadcasting.

So what does a mixer do and where does it come into play? A mixer does exactly what it’s name implies. A mixer allows you to mix multiple audio sources and tweak the dynamics, volume, and harmonics of each sound individually. A mixer also handles audio routing. That is, it routes audio signal to a specified location.

If you’ve ever had the opportunity to see a production setup for a music concert, you’ve probably noticed that there are lots and lots of audio cables involved in the setup. You’ve probably wondered how do they get all the instruments, microphones and lights in sync, mixed and working together. The majority of this is done by a mixer.

Generally, when you use an analog mixer with your computer setup, all your devices such has your microphone, outboard gear, and other audio sources will plug into your mixer. Your mixer then plugs into your sound card which is connected to your computer.

Now a mixer isn’t really a requirement if your going to be only using one microphone, however having one does make life easier when you have multiple audio sources and having one around provides scalability for you in the future.

A simple ideal setup will look something like this. Your microphone connect to the pre-amp/compressor input . Then the output of the preamp will lead to your sound card. The output of the sound card connects to your computer.

basicchain

A simple ideal setup with a mixer will look something like this. Your microphone will connect to your preamp/compressor (Assuming your mixer doesn’t have one on board). The output of the Preamp/compressor goes to the input of the mixer. The output of the mixer goes into your sound card which is connected to your computer.

chainmixer

Though audio technology talk can be a boring topic for some, it is truly one that is VERY IMPORTANT. It’s a crucial piece in making sure whatever media you are delivering sounds good and relayed clearly. If people can’t understand what your saying b/c of your quality OR if you have poor audio quality, your project or message can be quickly over-looked. With a basic understanding of audio, the audio components covered in this blog and some effort, you can be on your way to the top with audio quality like the pro’s.

Comments

  1. Chris Trak says:

    ya kno….I do feel smarter………mix it up, I say!

  2. I run most of my Bigger Instruments through [Stereo] Sub Groups and then run compressors on that such as Drums, Guitars, Vocals, percussion, etc. For Keyboards, pads, etc I tend to run a compressor [if needed] on the individual channel and assign them to a DCA rather than a subgroup. for the mains [I do live sound] I usually don’t compress much unless really needed as it can make it should more like a recording than a concert. but I do run limiters on my System Processor to protect the mid-high[bi-amped] cabs and subs from clipping.

    • That’s a good point Chris. Yea, there are times when I assign multiple channels to a single bus and just add very little compression to that bus. It just really depends on the project and the frequency and sound of the audio. Every engineer or audio tech has their own audio chain and way of routing. It’s that GREAT sound that the majority care about. You made some very good points man. Thanks for the feedback!

  3. “… climax the singers voice reaches louder volume. However, even when a singer is practically screaming into the mic while maintaining a note, the overall volume does not sound louder in volume as any other part of the song. This is because a compressor is keeping those very loud decibels at a specified level.”

    I would say singers that know good mic techniques go along way with this as well. too bad it seems fewer and fewer are trained on how to do that.

  4. Great article! I am now wishing I would have held-off on buying the Blue Yeti and purchased a better setup. Then again, I’m not singing, but I think the quality still would be much better.

  5. Chris, remember…you don’t HAVE to go with hardware outboard gear (compressor, mixer, etc). You can also use software versions of this hardware. Obviously, it will utilize more resources from your computer, but can work and sound just as great!

  6. I really want to get Pro Tools now (too bad it’s more than I want to spend now) It would allow me to make some great live albums especially since I have audience mics now (which makes a big difference) and it’s great for virtual sound checks too. I didn’t really like Logic Pro, just not the same to me.

    • There was a time I hated apple computers, today it’s my primary choice of use. There was a time I hated ProTools because of it being so hardware specific. Over the years I was forced to use it, and today it’s my primary workstation of choice. I get what your saying, but sometimes you just really have to spend time with the technology and understand it in depth. :-)

  7. @Lewis: I am seriously thinking about selling my Blue Yeti microphone (ya I know… it’s practically brand new haha) and really look at some professional audio recording equipment. It’s mainly going to be used for “voice-overs” (aka screencasts). This past weekend I purchased 7 boxes of Ultra Sonic Acoustic Panels (each box contained qty 6 12″x12″ tiles) to place around my recording area. I noticed the echo is much better now (and still have a couple boxes to install somewhere), but I still notice a hum in the recordings.

    Anyways, I guess I am looking for any advice from an expert like yourself to help guide me in the right direction. I am looking for really good audio quality, limiting the amount of outside noise (planning on purchasing a boom stand and shock mount so I can keep the mic close to my face).

    Thanks in advance!

    • @Chris – Your cables and your A/D converters are two of your most important factors when looking for a good quality signal. I use the limiter on my compressor to limit the “Outside” noise. If the loudness of the audio signal does not meet the threshold i have set, then that “outside noise” or background noise doesn’t come through. In other words, your telling your compressor/Limiter that the audio sound has to be “xxxx” loud in order for it to pass through the audio chain.

      That being said. My recommendations would be a 1) A good audio interface… 2) A good pre-amp ….3) A good mic.

      I’m assuming your looking for audio hardware for your videos. In that case, please note that everything listed below is what I would consider very affordable for the average user and good quality for your bang for the buck. Perhaps this could give you some direction

      Affordable Microphone Suggestions
      Rhodes NT1-A
      Studio Projects B1 or C1

      Affordable Audio Interfaces
      Focusrite Scarlett

      PLEASE do not skimp on the cables. Quality cables are better shielded and do an excellent job of keeping signal interferences / noise out. Monster Cables make really good cables and have EXCELLENT warranties.

  8. These would be my top 3 mic picks. You will also one high quality mic pres/A-D converter IO box behind these (must provide phantom power) to get good sound with low noise.

    http://www.sweetwater.com/store/detail/U87SetZ/
    http://www.sweetwater.com/store/detail/KSM32/SL
    http://www.sweetwater.com/store/detail/NT2AStuBun

  9. Thank you Lewis and Jason. Since there is a fairly large price difference between the following, is there also a big performance difference?

    Rhode NT1
    Studio Projects C1

    For the audio interface, this says it has a USB interface; does that mean I could use it as an audio source within ScreenFlow while recording my screencasts, or do I have to pull the recorded audio into ScreenFlow during post?

    Thanks for all of the awesome advice!

    • Jason threw a link for the Rhode NT2A – which is priced between the NT1A and Studio Projects… oh boy… too many different options LOL

    • In regards to the difference between the Rhode NT1 and Studio Projects C1 there is a noticeable difference. The Rhodes in my opinion has a more warm and full sound whereas the Studio Projects has a much Lighter sound and seems to cater towards more clarity and a higher frequency tone. I consider both of these pretty good mics. If I had to choose between the two, it would probably be the Rhodes. My ears and preference tend to like the warm and full tone that it offers.

      In regards to Screen-Flow, I’m not familiar with that software. However, if the software allows you to record into it from a microphone, then yes…you should be able to use the USB audio interface (Focusrite Scarlett) with that application.

      Think of the audio interface as a portable sound card (Which it is). You simply plug it in, install the drivers, and in your OS control panel you would select it as your primary sound card.

      In regards, to the NT2A – It offers a little more than the NT1A and the Studio Projects mic. It has a ‘high-pass’ filter, a control option for the polar pattern, and a selectable decibel variable pad. Though the sound from the NT1A is a VERY VERY hard one to beat for a mic in it’s price range, the NT2A does add a little more sparkle to my ears. Having the extra selectable options and the dual diaphragm facility that this mic has, provides a pretty AMAZING sound.

      • Thank you for the detailed advice Lewis! I just got the “OK” from the wife to buy what I need to buy. But, being the cost is a bit more than I think she is aware, I am going to start saving some $ for the NT1A and Focusrite Scarlett.

        In the meantime, I think I am going to work on finishing up the acoustics of this office by hanging blankets from the ceiling to the floor (to make my recording area smaller, less hard surfaces, etc.) and possibly add the acoustic tiles to the ceiling too.

  10. Hey Lewis, if you saw my recent post regarding my new setup (http://pc-addicts.com/march-2014-office-tour), I am looking to improve my studio’s (more like an office) acoustics by hanging some material (perhaps moving blankets) from the ceiling to corner off and seclude my desk area. Do you think that would have any impact to help reduce echo for my recordings?

    Also, I am looking at mounting some of them acoustic panels that I have on the wall now, to the ceiling above where I sit.

    This reminded me, are you still planning on any DIY room acoustic tutorials? I would LOVE to read/view some of them! ;)

  11. Yep, I just watched your video. It looks like your area is coming along! I’m not sure if I know what “Moving Blankets” are? I would assume if the material can absorb sound, then it will help.

    The panels you have on the wall should help quite a bit. If your looking to tone down the reverb when your talking into the mic, then you can do a couple of things.

    The first and the cheapest thing you can do…. well, It’s actually free. Scoot closer to the mic! LOL. A lot of people miss this step but it’s a VERY IMPORTANT one.

    The second thing you can do is invest in a microphone acoustic shield. I have NOT personally used one of these, but I’ve been in several recording studios with very large recording rooms that use them often. Check the link below.

    http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=Microphone+sound+shield&rh=i%3Aaps%2Ck%3AMicrophone+sound+shield

    Last but not least, you can do what your doing and acoustically treat your room. This can become very costly (depending on the size of the area that needs treating) but it does get the job done. This also requires the most creativity. I say that because you’ll be changing the look of your room by adding items that absorbs reverb.

    In regards, to the room acoustic tutorials…I’m still thinking about creating such tutorials and how to go about it for future videos. As of right now, I don’t have any hard dates set.

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