Keeping Up with REAPER Video

The REAPER forum is a regular stop for me. That’s where I learned about video in REAPER and where I look for the latest info. The video implementation is actually still in Alpha form, so it’s not fully supported and documented. Here’s the thread that announced the use of FFmpeg libraries.

Forum member airon has created a thread where he tracks the current state of video in REAPER, “Video Playback and Exporting” that I check often. He keeps it updated with the current FFmpeg libraries of choice, along with other news and tips.

Here’s the Cockos Wiki page describing video support. It includes details on installing the library files.

With all my enthusiasm, please remember that there are no video effects in REAPER currently. No fades, no transitions, no flipping or stretching. All we can do is move clips (and stills) around, trim them, and sync with separate audio tracks. So our style will be defined by those limitations.

Titles and Tricks

A static title is pretty easy to add to your project in REAPER. Just create a jpeg or png image in your favorite tool, heck, Windows Paint will do the job. Be sure to set the size to match your video, for instance 1280 pixels wide by 720 pixels high is a common HD video size. Start with an image or create a gradient, then add text, maybe in a couple of stages or pages. Then drag these into REAPER, drop them on the project timeline, and stretch them to match the tempo of your clip. You can see this technique in action in the tutorial video below.

You might have stills that contribute to your video, or a second or third camera shooting. Or you can extract stills from your video and use those for effects. REAPER 4 can handle multiple tracks of video along with multiple tracks of audio. The audio from all the video tracks will be part of the mix, but only the lowest (highest track number) video will be displayed. Once again, watch the video below to see these operations.

If you mute a video track it stops displaying the video as well as turning off the audio. To eliminate the audio but keep the video, just turn down the volume slider on the track, or use the Item Properties to turn down the audio.

Syncing and Slicing

The audio waveforms displayed in REAPER make syncing multiple video and audio clips a snap, especially if you create a sharp noise at some point when all the devices can capture it. The is exactly like the old “clapper board” you see in movies about making movies. You can simply clap your hands to get a spike in the audio that makes syncing easy.

Once you have tracks synced, take care to keep them that way. Use Item / Group to join items, or be careful to select all the items that belong together when you move, stretch, or trim items. In the video below observe how easy it is to select multiple items to keep them in sync. Also, I’m using ripple editing most of the time to maintain the correct relationship between items.

Cutting video items is just the same and just as easy as cutting audio. Select the item, position the edit cursor, press the S key, and your item is split at that point. As above, make sure all the items that you’re keeping in sync are selected and get split appropriately. I use ripple editing a lot when I’m trimming out parts of my videos.

Tweak the Audio

Even though there are no video effects available, the full range of audio processing definitely is present when working on video in REAPER. For instance, the clip I’m working on in the tutorial video below was shot with a Zoom Q3HD for the main video and audio. I raised the level, added some compression, applied a touch of reverb, and then put a limiter on the output to make sure I didn’t clip. The Q3HD delivers pretty clean audio but it tends to be a bit low in level and punch, so the ability to tweak the sound really adds to the usefulness of this little camcorder.

Rendering

Currently the h.264 video codec seems to deliver the goods for internet video. With the FFMPEG codec library installed in REAPER this is my preferred output. So I select the following options:

Output format: Video (FFmpeg encoder)
Format: QT/MOV/MP4
Size: 1280 x 720
Framerate: 29.970
Video codec: H.264
Bitrate: 9000
Audio codec: 16 bit PCM

Watch the Action

I used the Q3HD and a Creative Vado 3rd Gen to shoot an old Hawaiian slack key standard, My Yellow Ginger Lei in the style of Uncle Leonard Kwan. I decided to turn the video into a little tribute to my Kathy Wingert Model E guitar, so I used the guitar for the title still and shot a video of the guitar on a stand. Then I used REAPER 4 to combine those elements into a final clip for YouTube.

While I did the editing job, I shot with a couple of Sanyo Xacti HD2000s and recorded audio on a Zoom H2n. I edited those together to create a tutorial video:

and by the way, I put that tutorial together in REAPER 4 as well.

If you’re interested here’s the finished version of My Yellow Ginger Lei on my slack key channel:

I don’t think anyone is going to cut a major motion picture in REAPER, but as a way to tweak YouTube performance clips quickly and easily with an emphasis on audio, it’s a pretty decent tool.

Rode NT4 Into Everyone

So I turned to the wonderfully flexible Rode NT4 stereo mic as a source, installing the 9 volt battery that allows it to work without phantom power. Then I put together a chain of adapters to connect the mic to a Coleman Audio LS3. I bought this gadget years ago as a monitor switcher, but it also works as a passive distribution box for comparison tests like these. The LS3 gave me three outputs and another chain of adapters turned those into stereo mini plugs for the three recorders.

The mic, three field recorders, and the switcher

LS3 to 1/4" TS to RCA to Stereo Mini

Capturing the Tracks

As usual I “printed” or recorded a 1 khz test tone at the start of each recorder track. This is a snap with the single mic feeding all the recorders. I planned to create a set of tracks you can download in raw form as well as a set of level matched tracks, so I kept the recorders running while I moved the speaker and fired up my Martin OM-18GE, tuned to taropatch open G. I played a few hard strummed chords, some harmonics, then the first verse of “Sanoe” by Queen Liliu`okalani.

Here are those raw tracks. Please be very careful with your levels when playing these tracks, they contain loud piercing test tones than can hurt your ears and your equipment if played too loud!!

D50

H2n

H2

Level Matching Tutorial

I did some level matching on the clips and used the Licecap screen capture program from Cockos, the REAPER folks, to make a video of the process. I’m using the Sonalksis Free G Stereo meter on each track. This not only tells us the level on a fine scale, it allows precise level adjustment separate from the track fader and master fader. I find it indispensible for this kind of work. I also keep my monitor and headphone volumes down. Test tones can hurt your ears and your gear (second warning!) And I turn off snapping since we’re not dealing with beats and bars.

Here are the resulting clips. Remember, our brains love labels and they will affect what we hear based on those labels, so if you really want a clean comparison you need to use a double-blind testing tool like foobar2000 on the PC or abxer for the Mac.

D50

H2n

H2

What the Tails Tell Us

I’m usually not too concerned about slight variations in frequency response when I evaluate mics or recorders. I don’t want the recording to sound like it came through a megaphone, but minor colorations don’t seem to me to affect the emotional impact of the recording. I do listen for self-noise, though, because noise is a distraction, a mask over fine detail, and it breaks the illusion of “being there” that I look for in a track. So I often find myself listening to the “tails” of tracks when comparing recordings. For this comparison I went to the end of each track and selected an area after the last note had begun to decay, raised the level a lot, 12 dB, and rendered those for you.

D50

H2n

H2

Conclusions

There’s a look at our three recorders when used with an external mic. I’d say it’s pretty clear that the Sony tops the field here in low noise performance, and the H2 is bringing up the rear. In an earlier post I compared the H2n to the Echo Audiofire and was not too impressed, but now that I hear it in the context of other portable recorders, I’m much happier with the new Zoom. At least for the limited purpose of capturing solo acoustic guitar in a small room, the Zoom H2n is in the ballpark with the Sony. If your needs are more demanding, something like nature or sound effects recording, you may find that the Sony provides more clean gain, something I haven’t tested.

The first thing that jumped out at me – the new box is a lot smaller.

How'd they make the H2n box so much smaller?

Not the result of a breakthrough in packaging efficiency, I’m afraid. The reason is the lack of accessories. The AC adapter is missing, as is the mic clip adapter stick. These useful bits are now part of an extra cost accessory pack which adds $40 to the price of the H2n and includes stuff that I already have or wouldn’t use. Bummer, as we used to say in the 60s.

Not much in there, is there?

On the other hand, the AC adapter is a USB connector type, so maybe I have something around here that will work, and the long battery life makes the AC adapter less necessary. And I’ve collected a couple of mic sticks already, so for now I’ll skip the accessory pack. And I’m happy to see Wavelab LE7 in the package. Maybe I can get rid of my Adobe Audition and use this instead.

Look and Feel

The look of the H2n is cool black, the new screen is bigger and brighter. This is my number one reason for wanting the new unit – I can operate the menu without glasses. This screen is still pretty lame compared to the beauty they put on the Q3HD, though. The H2n screen is monochrome and pretty low in resolution.

Cool black vs classic silver

The menu is similar to the H2, but a bit simplified. The menu interface is simple and direct – a menu button takes you in and out of the menu, the playback paddle serves to select options. The buttons all operate much more easily and positively than those on the H2, but many of the H2 buttons are covered by a plastic skin which should add longevity even though it reduces tactile feedback.

SDHC card access is not quite as easy as the H2, it’s one of those uninspiring “flexi-hinge” covers and it’s pretty stiff right now. When I see one of these I figure there’s going to be duct tape on there someday. To be fair, plenty of people complain about the H2 hard plastic cover, and I’ve read reports of failure (and replacement with duct tape).

The battery compartment is a big surprise – the batteries both go the same way!! First time I can remember this configuration, usually two AA batteries would go opposite each other.

Operation

There’s no “Standby” mode as in the H2. The unit is listening and giving meter readings as soon as it’s turned on. Press the big red button all by itself on the front and you’re recording. Press it again and you’re not. Standby is a feature that has been part of recorders for a long time, but I know I am not the only one who missed many recordings because I only pressed the H2 record button once. I’m not sure which bit of technology made this new design possible, but I see it as a step forward, as soon as I can get out of the habit of pressing record twice – oh no!

Headphone monitoring can be turned off or turned on constantly, but the default is to have monitoring on at the home screen or while recording.

Files can be named with a date time stamp!!! No more hassles with duplicate file names when combining different recording sessions!!

The two obvious changes on the recording side are the level setting and the mic options. Instead of a three position analog “Mic Gain” along with a digital “Rec Level” control in the H2, the new recording has a continuous thumbwheel controller that is advertised as analog. My first impression is that the H2n offers much higher overall sensitivity than the H2, which will be a big benefit to nature recorders if the noise floor is adequately low.

The mic arrangement is interesting. There are still two mic arrays inside the H2n, but now there are five mics instead of four. A classic XY array (two cardioid mics at a 90 degree angle to each other, 45 degree angle to the source) points to the front of the H2n, as it does in the H2. The back array on the H2 is a pair of cardioids at 120 degrees, giving an option for a wider stereo field. In the H2n there are three mics in the rear facing array and they are combined into an MS (mid-side) configuration. This consists of cardioid mics facing opposite sides and in opposite polarity, so the two mics together emulate a single figure 8 mic at right angles to the source, while a single cardioid mic faces directly at the source and serves as the mid mic. The mid and side mics are then combined mathematically to yield a stereo field. The H2n can save either the decoded (stereo) or raw (mid and side separately) files, and it can be monitored in either mode as well. This is a nice bit of flexibility. In addition, you can adjust the amount of the side mic mixed into the decoded stereo file, changing the width of the stereo image. Visit the Zoom H2n site for a detailed explanation of the mic arrays and how they can be combined and adjusted.

I have this strong feeling that the real benefit of the mid-side (MS) mic arrangement is the marketing buzz it generates, but there are probably many users who will find a benefit in the ability to adjust the stereo width at record time. I’m guilty at times of seeing the whole recording world in terms of solo acoustic guitar, I’m afraid. I would add that the mic selector can be a bit difficult to adjust. It’s a small circular nob with a somewhat slick surface, so a slight case of sweaty palms can make it impossible to change mic patterns.

The playback speaker is a very nice addition. We no longer have to carry headphones just to confirm that we got something. Playback is controlled by the same jog-and-press wheel that navigates the menu. These things always feel a little uncertain to me, but it gets the job done. The headphone out is clean and clear, I’m thinking this unit will work very well as a powered mic to feed into a video recorder like the Q3HD.

Recording Samples

I was satisfied with most aspects of the H2 recording quality, except for the low level noise. My big hope for the H2n is an improvement in that area. I set up a comparison by putting the H2n, the H2, and a Rode NT4 stereo mic next to each other.

Rode NT4 between two Zooms

The Rode was connected to my Echo Audiofire Pre8 interface. I played a 1 khz test tone into all three recording chains, adjusted levels to avoid clipping, and recorded the tone. With the recorders still running I played a bit of slack key guitar, and left a nice long “tail” at the end of the recording complete with tummy gurgles. This ending section where the last note dies off is a classic place to hear self-noise generated by mics and preamps, along with the room noise (and the belly noise).

After recording these clips I pulled them into REAPER, put the Sonalksis FreeG stereo meter on each track, selected the reference tone in a loop, and adjusted the level of each track so they were within 1 dB or so. This is barely adequate level matching, but hopefully it will be revealing of the differences in noise level. I trimmed off the test tone when I rendered the sample files – no one should be subjected to a 1 khz tone if they don’t have to be. I also made a second set of clips with just the tails, and here I raised the gain significantly.

Zoom H2

Zoom H2n

Rode NT4

Zoom H2 Tail

Zoom H2n Tail

Rode NT4 Tail

Conclusions

Knowing what I do now, I’m glad I got the H2n. The improved battery life will make my recording projects easier, and the more readable screen will help as well. But aside from those issues, I’d say the H2 holds its own very well in this comparison. For many projects the difference in audio quality is probably not enough to justify a switch. For someone on a tight budget the H2 might still be a good purchase, especially if their eyesight is good.

*** Update ***

Down in the comments, Boston Dave asks about how the H2n deals with loud sources. I banged away pretty vigorously on my Martin and from looking at the wave form and listening to the result I think turning down the mic gain wheel successfully eliminated clipping. You can download the test clip, it’s straight from the recorder so it’s a little ungainly, but perhaps it will be useful to someone.

H2n High Volume Test

I’m afraid that in some cases, simple physics is the culprit, helped along by our experience listening to modern recordings. We’re used to bigger than life sounds and close mic positions because that’s how most pop music is recorded. When we put our Q3HD in a location that gives us a conventional picture of a seated guitarist the camera is usually about four feet from the guitar. That four feet make the sound of the guitar weaker, and allow more of the room sound to intrude. This is called the direct to reflected ratio, and while we need some reflections to make a natural sound, the quick reflections of a small room generally don’t make for a pleasing recording. There’s another important ratio that suffers from a distant placement – the signal to noise ratio. Less guitar signal means we notice the surrounding noise more.

Several people have complained about the low level of the recorded audio and suggested that the Q should provide more preamp gain. But when you consider things for a moment you realize that more gain means more room reflections and more noise along with more guitar, because these ratios are established before the recording begins. So more preamp gain gives the same result as simply turning up the volume on playback in terms of room reflections and background noise.

The real solution is to move the microphones closer to the source. But that’s going to mean our conventional picture loses its head, and its hands. Since the conventional picture won’t work, we just have to get a little more creative, and find a new way of looking at the guitarist. Let’s start by positioning the mics in a good location for the audio, then see if we can find an interesting picture.

I usually use mic stands to position the camera – I have several boom stands, and they give me more flexibility than a typical tripod. I use the Zoom MA2 Mic Stand Adaptor or the Edirol OP-MSA1 to attach the camera to the mic stand. Interestingly, the Edirol adapter costs more and looks much more sophisticated, but the simple stick from Zoom does a great job and is handier in many ways.

I put together a video showing some different locations for the Q3HD using this concept of positioning for audio first. The first is the classic “off the 12th fret” location nearly universally recommended as a starting point for recording acoustic guitar. Actually, I used two variations of this, one below the guitar pointing up, one above and pointing down. From there I moved to the “off the bridge” lower bout position, and finally I tried the “over the shoulder” position that places the mic near the player’s ear.

In the video you can see the locations and quick samples of the audio and video that result from each position. All of these could be improved for both sound and picture by some extensive tweaking, and of course it’s a lot easier with two people than one.

In the process of creating the tutorial I realized I had enough material to put together a music video, a somewhat quirky one but perhaps an interesting project. I decided to try to edit the clips in REAPER, and with a bit of patience I was able to pull it off. I used Cockos LICEcap and the GIMP image editor to create a title, and rendered the results as a 1280×720 29.970 fps .MOV using the FFmpeg libraries. Here’s Waialua Slack Key as seen through the Zoom Q3HD at various angles:

I wouldn’t call the video an artistic masterpiece, but it serves to demonstrate the different angles and differing timbres of the audio captured from different locations. Hopefully it will serve as a bit of inspiration for other folks trying to get great audio and video from their Zoom Q3HD.

Now for the icing on the cake – the development team has linked in the FFmpeg video libraries and given REAPER the ability to do simple video editing. I’m totally happy with my video editing system since I moved to Edius Neo 2.5, but when I played around with video in REAPER I realized that this is a tool many musicians want and need.

Many of us like to post simple performance videos on YouTube – not big production numbers but simple clips showing off our latest tune or instrument or technique. And we want to do this on a budget. We use inexpensive pocket video cameras, and they have at best mediocre sound quality. Many of us also have a fairly high quality recording system of some kind. Now with REAPER we can create our videos just like they do it in the movies – recording the sound on a high quality audio system positioned for the best audio quality while capturing the video at the distance needed for framing and perspective.

Using video in REAPER is a snap. First, go to the CockosWiki Video Support page for instructions on adding the FFmpeg libraries to the REAPER program directory.

Once the FFmpeg libraries are in place, just open the video file like any audio file, or drag and drop from your file browser into the REAPER track window. I’ve tried clips from three camcorders so far, the Kodak Zi8, the Flip Ultra HD, and the Sanyo Xacti HD2000. REAPER handled all of them with ease. Only the .mts files from my Panasonic Lumix TS2 failed to open, and I was able to convert them to an AVI that REAPER liked.

If I’m shooting video around my studio, I’m all ready to record audio into REAPER, so there’s another step out of the way. If I’m shooting on location it’s a snap to bring the recordings back to the PC and drop them into REAPER. The whole process is so easy that instead of writing detailed instructions I decided to simply shoot a video of shooting a video and demonstrate the syncing process.

So that’s how easy it is. Drag and drop, drag and drop, trim, drag and drop, trim, and render. When I think of the hours I’ve spent calculating frames in Avidemux, or waiting for Premiere Elements to redraw, or being told by Windows Movie Maker that it can’t deal with my file …

Here’s the video that I created in REAPER in the process of the tutorial. The Flip would have been happier with more light, for sure, but the quality you see in this video is right there with the original from the Flip. And the audio is in a whole different, and better, league. Naturally, since I was working within REAPER I could have easily added effects, applied EQ, worked over the audio to improve the result.

As I expected, some folks reject the validity of these controlled tests, stating that different mics respond to different positioning in different ways, and their performance in their optimal position is the important issue. I can only suggest that they try some controlled testing in those different positions. After all, if the difference really exists, it should be apparent when levels and positions are matched, right?

And as I expected, some people pointed out that mics with different patterns and mics with very different transducer technology, like ribbon mics, sound different from the cardioid condensers I used. I absolutely agree.

Also as I expected, some people suggested that my use of a single source, the acoustic guitar, is preventing me from hearing the differences, which show themselves on cymbals and vocals. As Dirty Harry was wont to say, “A man’s gotta know his limitations.” I don’t record those sources so I don’t use them for testing .

One comment that has come up a couple of times is that the mics I chose were too similar, all large diaphragm mics from the low end of the spectrum. So I pulled out my highest priced mic, a Schoeps CMC64 small diaphragm condenser, and stuck it in the array.

Variety is the Spice of Mics?

For a little more variety, I replaced the Rode and AT mics with the Shure KSM141 and KSM44. So this set of clips includes two large diaphragm mics and two SD mics, and the price spread ranges from under $200 to over $1500.

I followed the same procedure I illustrated in yesterday’s post, aligning mic diaphragms by eye, playing a test tone through a small speaker about 1 foot from the mics, then adjusting gain on the M-Audio Profire 2626 to match their levels as well as possible in Reaper. Then I recorded the test tone followed by the acoustic guitar clip.

Mics and Clips

So here are the mics:

CAD M179
Schoeps CMC64
Shure KSM44
Shure KSM141

and here are the clips:

download 20090626-F.wav
download 20090626-G.wav
download 20090626-H.wav
download 20090626-I.wav

As before, I’ll post the key to the clip identities in a future blog entry. Or if you post your opinion and preference in a comment here or on one of the forums I visit I’ll email or PM the information to you.

Philosophical Musing

Please let me take a moment to wax philosophical here. No one has reported doing double blind ABX comparisons on the clips so far. Several posters have offered opinions on the sonic qualities of the clips, but no one has confirmed that they can actually hear a difference! This seems to be human nature, but I think that skipping the double blind check is missing a really valuable learning experience.

Sometimes when I’ve listened to mic samples I thought I heard these dramatic differences, but after a bit I realized that I was listening to different performances, not different mics. Sure the mics had been changed, but the player was hitting the strings differently and playing different riffs at a different volume – so how could I tell what part of the difference was the mic, and what part the player?

Since then I’ve tried to do some mic tests of my own, and I’ve tried to educate myself on audio testing. At this point I’m beginning to think that the differences in microphones are a lot more subtle than I had been led to believe, which makes a careful test even more important. As I’ve mentioned before, very small differences in volume are registered by our ear/brain combination as differences in quality rather than loudness. I’d like to demonstrate the steps I now take to try to make my mic comparisons, and preamp and a/d comparisons, meaningful.

Mic Setup

The mics need to be close together, but not interfere with each other. I try to determine the location of the diaphragm, the part of the microphone that gets hit by the sound waves, on each mic, and align them along that position. This is pretty easy with large diaphragm mics, often a bit tricky with small diaphragm units. All the mics should be on axis to the source or all should be equally off axis. Check pattern switches, rolloff settings, pads, any feature of the mic than changes its response. I’ve missed this step a few times.

I also arrange the mics so they don’t interfere with each other. For instance, it’s not a good idea to tie a bunch of small diaphragm mics into a bundle, because the ports behind the capsule contribute toi the frequency response and pattern of the mic. If those ports are blocked the mic is not performing normally.

There are three mics being compared in this example. The CAD M179 is a low cost continuously variable mic in an unusual looking housing. One salesperson began a drumbeat for these mics and they are now widely recommended in internet recording forums. The Rode NT2a is one I’ve used before. I think it does a fine job of capturing audio with low noise and no noticeable distortion, but many forum posts are negative toward Rode in general and the NT2a in particular. The Audio-Technica AT3035 has recently been discontinued, replaced by the AT2035. In the past I’ve read a wide range of comments about this mic, with some calling it a secret gem and others decrying its overwhelmingly bright character.

Here’s a picture of a mic array arranged for testing. A cheater clamp that fastens to the mic stand main tube can help fit an extra mic into the array. Adapters to attach mics at an angle can be very handy as well.

Three large diaphragm mics in an array for comparison

I often hear this arrangement, with all the mics equidistant from the source, criticized because different mics work best in different positions. I strongly suggest that if you wish to evaluate different positions you try all the mics in all the positions. It’s a little more trouble, but it’s a great learning opportunity, and omitting this step means no valid comparison can be made. We’re right back to asking what part of the difference is the mic, what part is the location with no way to answer the question.

Of course, my aim here is different from trying mics and positions to get a good recorded sound. I’m after data, not art. When the aim is art, the ears rule!

Equipment wise, you can do a useful comparison with as few as two recording inputs. In fact, comparisons that are done two by two are probably the most revealing and useful. Still its fun to line up three or four mics for a single session – in which case it’s helpful to have four identical channels, especially if the comparison will be made public. In my experience, more posters will criticize a change in preamp than will mention a change in performance, amazingly enough.

Here’s a video that illustrates the setup process and takes you through gain calibration, discussed below:

Microphone Comparison - A Tutorial - part 1 of 2 from Fran Guidry on Vimeo.

Gain Calibration

Once we’ve arranged the mics to capture a single performance we need to minimize the volume difference in the our samples. I like to start with a test tone played into all the mics from a speaker only a foot or so away. A 1000 Hz tone is not very challenging, so even a low cost computer speaker can be used as the source. A test tone is easy to come by and it doesn’t need to be calibrated for volume since we’re interested in relative rather than absolute levels.

I’m using Reaper to conduct this test, and a little inquiry on the Reaper user forum and learned about MDA Test Tone, a plugin that provides the beep.

In Reaper I created a project with MDA Test Tone on one track, and three tracks for recording the three mics. I also adjusted the range of the Reaper console meters. With these connections in place I hit record and adjusted the preamp gain for each mic so they all were very close to -18 DbFS.

Next I discarded these recordings and captured three more tracks to store a consistent level for each mic. These 1000 Hz tones are used to fine tune the track levels later.

Recording

In the next video we actually do a little recording. After all the setup and calibration work, the recording process is anticlimactic. Move the calibration speaker, tune up the guitar, hit Record in Reaper, play a few bars, and we have our clips in the can. Be sure to record the clips on the same tracks as the reference tones we created in the last step. That way when we adjust the reference tones we adjust the clips at the same time.

For straight mic comparisons, I like to position the guitar about 32″ from the mics. This avoids proximity effect and hopefully presents a fully developed guitar sound to the mics, instead of one mic picking up the neck of the guitar while another picks up the bridge.

Here’s the video demonstration of recording simultaneous tracks and fine tuning the gain:

Microphone Comparison - A Tutorial - part 2 of 2 from Fran Guidry on Vimeo.

Volume Fine Tuning and Rendering

As the video illustrates, working with that 1000 Hz test tone can be pretty annoying, but we need to delve into it one more time. Actually, this time we can turn the volume down, because we’re adjusting levels “in the box” – that is, internally in the computer.

The helpful folks at the Reaper Forum pointed me to the Sonalksis FreeG plugin. This tool adds high resolution metering and gain adjustment we can use to tweak the levels of our clips that last little bit.

Simply place the Reaper track cursor so the recorded test tone will be played, reset the FreeG meter, and play a bit of the clip (the space bar starts and starts playback). Note the RMS level, and repeat for each track. Then, to be fair, apply a gain adjustment to each track so they all show the same RMS level. In the video I’m fiddling with the Gain knob using the mouse, but after I recorded the session I realized that you can simply type the desired gain change into the value box, making it very easy to get the level just right.

Finally, click and drag the cursor to make a time selection of the recorded clips, then render each track separately as illustrated in the video. It’s a good idea to render to 44.1/16 format if you plan to make the clips public, because everyone can play this CD standard format.

Blind Comparison

I have had the experience many times of listening to mic comparison clips and clearly hearing the difference between them when I knew their identities, then finding that I could not hear a difference at all when I hid the identification in some way. Even getting momentarily confused about the source of the clips has been enough to change what I “hear”. Our brains are at least as important as our ears in defining what we hear, and our brains like new stuff, shiny stuff, expensive stuff. So when we know a clip was made with our shiny new expensive mic, we’re going to “hear” how wonderful it sounds.

For a test to be meaningful, we need to hide the identity of the clips somehow. This is pretty hard to do when working by ourselves. The foobar2000 audio player offers one solution, with the ABX testing utility built-in, as described in this blog post. This is a powerful tool, because it not only offers a way to test clips double blind, it helps us determine if we can hear any difference at all before we try to determine a preference.

Mic comparisons are useful for our own recording knowledge, but it’s even better to share. There are lots of folks hanging out at recording forums on the internet who are looking for information about mics and other recording gear. I like to contribute when I can by posting comparison clips, but I think it’s important to make the original post without identifying the devices used. It’s more informative, and more fun too.

So here are the three clips I recorded in the video, with no EQ, no compression, no reverb, no processing of any kind except to match volume levels and trim ends. To recap, the three mics being compared are the CAD M179, Rode NT2a, and Audio-Technica AT3035. Naturally the clips are not in the order listed.

download 20090625-J.wav
download 20090625-K.wav
download 20090625-L.wav

I’ll post the key to the clip identities in a future blog entry. Or if you post your opinion and preference in a comment here or on one of the forums I visit I’ll email or PM the information to you.