Product Name/Version: iMic, stereo headset, and USB Audio Hub
OS 9/OS X ?: Both
Company: Griffin
Category: USB audio devices
iMic: $US35
stereo headset: $US10 (or $US5 if purchased with iMic or NE Mic adapter);
USB Audio Hub: $US39
Requirements: Mac OS 9.0.4 or greater / Mac OS X
Date of Review: 6/14/02
Rating: Overall: 4 bounces, Pure Lust

When I bought my Power Macintosh G4/450 AGP two and a half years ago, it was my first-ever USB/FireWire-based computer. Of course, I had to purchase some extra gear in order to be able to continue using my pre-USB/FireWire peripherals (including a LocalTalk-based laser printer and an SCSI-based CD burner), but I still was excited by the new possibilities afforded by these next-generation connection ports.

As it turns out, my Power Macintosh G4 was also the last generation of G4 towers to include an audio-in port. With the next generation of towers, Apple came up with the concept of “digital audio”, which did away with the (analog) audio-in port, and made the assumption that, for any audio/video input needs, Mac users would now use their computer’s digital ports, i.e. USB and FireWire. In other words, if you wanted to do any kind of work that involved digitizing audio, you now needed either to use a source that was already digital (such as a CD or a digital camcorder) or a third-party device to transform your analog source (tape, vinyl LP, microphone, etc.) into a digital stream that could be fed into the computer using either USB or FireWire.

This opened the market for a new generation of third-party devices. Some of these devices, such as the ATI XClaim USB pod (also reviewed on this web site), are in essence transitional tools designed to let you continue using your analog devices (non-digital camcorders and VCRs and analog TV signals, in the case of the XClaim USB) with your digital-only computer equipment — until you are ready to replace them with all-digital equipment (digital camcorder, digital VCR or DVD recorder, and digital TV) that makes your XClaim USB obsolete.

Other devices, such as Griffin’s iMic, are basically tools that act as a bridge between things in our world that will always be analog (until we ordinary humans are replaced by a race of super-human cyborgs anyway) and your “digital hub”, i.e. your USB/FireWire-equipped computer.

What the iMic does

Contrary to what the name seems to indicate, the iMic is not a microphone. What the iMic does is basically two things: (1) it provides you with an “audio-out” port that lets you lets you listen to the (digital) sounds produced by your Mac with an (analog) set of headphones or through an (analog) sound system; and (2) it provides you with an “audio-in” port that lets you connect any (analog) sound source (such as a tape deck, a stereo receiver, or a microphone) and digitizes this sound source for you in order to then feed it to your Mac through one of its USB ports.

In other words, it is a simple device with two mini-jack ports, one for sound-in, and the other one for sound-out. The two ports look exactly the same, so you need to be careful not to plug the wrong kind of device into the wrong kind of port. There is a small icon on top of each plug which indicates what it is for, using familiar microphone (symbolizing sound-in) and speaker (symbolizing sound-out) symbols.

This does not mean that you are restricted to connecting microphones to the sound-in port. And it doesn’t mean that you can connect speakers directly to the sound-out port.

The sound-in mini-jack port accepts either a microphone or any other regular sound source. All you need to do to connect your receiver or tape deck to the iMic is to use a regular stereo RCA-to-mini-jack adapter, which you can find at your local electronics shop for a few bucks. You cannot, however, connect your turntable directly to the iMic. The signal coming from turntables is not strong enough and always needs to go through an amplifier, which can be your regular sound system’s receiver (using its “phono” RCA plugs) or a more portable amplifying device designed specifically for this purpose. This is perfectly normal, and you won’t find any USB audio device that enables you to connect your turntable directly to your Macintosh.

For similar reasons, you cannot connect speakers directly to the iMic’s sound-out port — unless they are computer speakers (which include a built-in amplifier). The signal coming from your computer through the iMic also needs to be amplified, like any other sound source, and the way to do this is either to use computer speakers or to connect the iMic to one of your sound system receiver’s regular RCA ports, again using a mini-jack-to-RCA adapter. You can, however, connect headphones directly to the iMic, which therefore can act as a substitute for your computer’s built-in “audio-out” mini-jack plug.

Using the iMic

Using the iMic itself is very simple. All you need to do is connect the iMic to one of your Mac’s USB ports (or to a USB hub), and then connect whatever sound source or sound outlet you want to use to its sound-in or sound-out port. The iMic draws its power from its USB connection, so there is no separate power supply.

Unlike many other USB devices, however, the iMic does not have any kind of light that comes on to indicate that the device is working. The only way to check if it is working is to go to your computer’s “Sound” control pane (in System Preferences) and check the “Output” tab. If the iMic has been detected properly, it should appear as “iMic USB audio system”:

Alternatively, you can also go to your computer’s “Speech” control pane (also in System Preferences), and check the “Listening” pane, where “iMic USB audio system” should appear as one of the options for the “Microphone” setting.

Now you can decide whether you want to use the iMic as a sound input device (to record sound on your computer) or as a sound output device (to listen to the sound coming from your computer) or both.

This is where it gets a bit confusing. The design of the iMic includes a small black switch located between the two mini-jack ports on the iMic. Given its location, it looks as if it is a switch that lets you choose between using the iMic as a sound-in device (when pushed toward the microphone icon) and using the iMic as a sound-out device (when pushed toward the speaker icon). However, this is not what the switch is for! The switch is for indicating the input type, i.e. microphone-level (for microphones) or line-level (for tape decks, receivers, CD players, etc.). In other words, the switch does not have anything to do with the sound-out port (the one with the speaker icon). It would probably have been more intuitive to locate this switch on the other side of the sound-in port, or on the top part of the device.

I also found the black switch a bit too small and too flimsy. You can’t tell from a normal distance which position it is on (you have to look up close), and it tends to switch too easily from one position to the other when you handle the device.

The other thing that was not entirely clear is whether the iMic fully supports “playthrough”, i.e. the ability to hear with the device connected to the sound-out port what you are recording with the device connected to the sound-in port.

For the purposes of this review, I used the iMic with my favorite sound editor, Amadeus II, and tried it with various pieces of audio equipment, including Griffin’s own stereo headset. The headset includes both a pair of headphones and a microphone, and you can use it in combination with the iMic by plugging its headphone mini-jack (blue-colored) into the iMic’s sound-out port, and its microphone mini-jack (red-colored) into the iMic’s sound-in port.

The dialog box in Amadeus includes a “Playthrough” checkbox that appears to indicate that you should be able to listen to what you are recording with the iMic:

However, when you try to click on this checkbox, it doesn’t respond. (The checkbox is not grayed-out. It just doesn’t respond to the mouse click by changing its state to “checked”.) It therefore appears that the “Playthrough” option is not supported. As well, when I used the iMic to record the sound coming from the “sound-out” port of my PowerBook (see below), I could not hear the sound using my headphones connected to the sound-out port of the iMic. I could only listen to the recorded sound with the headphones after it had been recorded, by playing the recorded file.

When contacted, a Griffin representative told us that the problem with playthrough is actually a problem in Mac OS X itself, and that they are waiting for Apple to fix the “Sound” preference pane so that playthrough is supported properly.

In the meantime, however, there is an excellent little freeware application called Playthrough FX which can be used in conjunction with other Mac OS X audio applications and enables playthrough.

I tried it with Amadeus and it appears to work fine, except for a buzzing sound that sometimes (but not always) rings in the headset when the playthrough option is off. This buzzing sound can actually be quite loud, so I strongly recommend that you turn the volume down before you try the application, just in case. (I didn’t, and my ears are still ringing.) When the playthrough option in Playthrough FX is on, however, I do not hear any buzzing sound, and the playthrough feature appears to work fine. You can even add fun delay and reverb effects on-the-fly.

Device Quality

The next big question for any reasonably demanding user regarding any audio device is: how good is the quality? In the case of the iMic, the question is a double one, of course: how good is its sound-in port? how good is its sound-out port?

Determining sound quality is obviously a very subjective thing. What might be reasonably pleasing to my ear might be unacceptable for a hard-core audiophile. In order to give you a bit of a frame of reference, let’s say that I am not a hard-core audiophile who owns a $20,000 sound system — but that I am still a rather demanding music lover. I listen to a lot of music with high quality headphones — but also to a lot of music in my car, which has a good sound system with a CD player, but where, due to the high level of ambient noise, sound quality is not as sensitive an issue as it can be indoors. I don’t often listen to music using computer speakers (of which I have a pair), both because I don’t like to listen to music while I am working, and because I much prefer the sound of a pair of real speakers on a real sound system (which, in my case, is in a different room). I do sometimes listen to music on my computer using a good pair headphones, however. Finally, I find MP3 files perfectly acceptable for a variety of uses, and I find that even a 128 kbps rate can still yield pretty good results (depending obviously on the type of music, of the quality of the source, and on the quality of the encoder’s algorithm). However, I would never use MP3 files as a substitute for CD-quality sound, and, whenever there is a piece of music that I like, I have to own it on CD (if it’s available).

In terms of quality, the claims of Griffin’s own literature are the following:

By using USB, the iMic provides significantly superior audio input and output performance over built in audio. The iMic is a must have product for people who are serious about getting high quality audio in or out of their computers. The iMic not only provides amazingly high quality performance but is remarkably inexpensive at a suggested retail price of $35.

My main goal was therefore to determine whether the iMic is indeed a “high quality” audio device that matches or surpasses the quality level of the equipment I normally favor for my own listening pleasure.

Audio-out

In my case, the audio-out port that was included on my Power Mac G4 turned out to be of uncertain quality. After I bought the machine, in 1999, I found that, whenever I played CDs above a certain volume level (using Mac OS 9 and Apple’s own AppleCD Player, back then), I would get ugly distortion in my headphones. I reported the problem on the Apple Discussions forum (the discussion seems to have been removed since then — it was more than two years ago), and I even got an engineer from Apple chiming in and asking if I could provide him with sound samples, which I did. I never heard back from anyone, but now, running Mac OS X on the same machine and using iTunes to play the same song, using the exact same pair of headphones, and the same cables, I am unable to reproduce the distortion. This leads me to wonder whether it was a software-only problem that was later solved through a firmware update or through system software updates.

In any case, I am unable to produce any distortion with the iMic either, no matter how high the volume level is. If I compare its sound-out signal to the one coming through the Mac’s own audio-out port, I don’t notice much difference. The volume level coming from the iMic is a bit lower (but not by a large margin), and the sound coming from the iMic is maybe a bit fuller and “rounder” (therefore more pleasing to the ears) than the sound coming directly from the Mac. I emphasize the “maybe” here, because obviously these are very subjective impressions. I don’t have the lab equipment necessary to make an objective, scientific analysis of the sound produced by the two devices. But they both sound very good to me.

I also used the same CD and the same pair of headphones on my sound system, which includes a good-quality CD player and a good receiver. I tried the audio-out headphone plug on the CD player itself and the headphone plug on my receiver. On the whole, of the four set-ups — same pair of headphones, same CD, but (1) using iTunes and the Mac’s audio-out port; (2) using iTunes and the iMic’s audio-out port; (3) using my CD player; (4) using my receiver — I would say that the one I prefer is (4). But that might simply be because (4) is precisely the set-up that used to be my favorite way of listening to music, in what might be considered my “formative years” as a music lover. It’s all very subjective, and the iMic obviously holds its own next to all these other possible set-ups.

Audio-in

Judging the quality of the iMic’s audio-in capabilities is, for the same reasons, also very tricky — but at least in this case I can provide you with some sound samples.

I first chose a track which I felt would be a good test of the system (Massive Attack’s “Protection”, of their 1994 Protection album), and used two different approaches to digitize it. The first one was simply to extract the audio track directly from the CD using my sound editor, i.e. Amadeus II. This procedure doesn’t actually digitize the track, which is already in digital form on CD. It just re-assembles the file from the audio data found on the CD, and produces a stereo, 16-bit, 44.1 KHz file, which you can then save in AIFF format. I kept the first 30 seconds of it.

I then took the same CD, put it in my PowerBook G4’s CD player, and then hooked up the sound-out port of the PowerBook to the iMic’s sound-in port using a straightforward mini-jack-to-mini-jack cable. I used Amadeus II, once again, to record the first 30 seconds of the track.

Finally, still with the same CD, and still with my PowerBook G4’s CD player, I hooked up the sound-out port of the PowerBook to my Mac’s own sound-in port, using the same cable. Again, with Amadeus II, I recorded the first 30 seconds of the track. (I noticed that I had to increase the “input gain” level significantly to obtain a volume level of approximately the same level as the other samples.)

I then proceeded to “normalize” the three tracks, which completed the process of bringing them to the same sound level and obtaining the best possible files for sound-to-sound comparisons.

Unfortunately, AIFF files are really large, which prevents me from giving you access to these 30-second samples in their original, CD-quality form for optimum comparison. (They are 5 MB each.) I saved them in MP3 format at 160 kbps using Amadeus II’s own conversion engine, which gave me three smaller files. And here they are:

As far as I am concerned, there is very little perceptible difference between a purely digital process such as the one I used for the first sample and the analog-to-digital process involving the iMic’s sound-in port that I used for the second sample. They both produce excellent results that should satisfy most music lovers out there. As for the third option, well, Griffin claims that their iMic is superior to the sound-in port of my Macintosh:

The Mac’s built-in audio hardware typically does not perform at professional quality levels, introducing noise and distortion. The inside of a computer is a very noisy place electrically; the power supplies are full of transient noise from the CPU, hard drives, CD drives and other computer components. The built-in Mac audio hardware can transfer that noise into the audio I/O (input/output). The iMic stays outside of your noisy computer system, attaching via the external USB interface. Normally this will provide improved performance for audio recording and playback.

I must admit that I remain dubitative about this. The third file, in my opinion, does not differ perceptibly from the one produced using the iMic. Then again, this test was done with just one particular Macintosh computer, and Griffin’s claim might have more validity for other Macintosh models. (To their credit, they also only claim that you may get better results. At the very least, you will get results that are just as good, and that’s important if you own a Mac that doesn’t have an audio-in jack, or one whose audio-in jack is defective.)

Voice Recording

My second test involved using Griffin’s iMic in combination with their stereo headset, which, as I said earlier, includes both a pair of headphones and a microphone. These are not of very high quality. It’s an affordable solution that can be used for purposes such as on-line telephone communications. (Until Steve Jobs decides to complete the “digital hub” puzzle and to provide us with decent telephone software for the Mac, unfortunately, this type of set-up cannot be used for regular telephone communications, for which you still need a separate, traditional headset.)

Still, I thought I’d give it a try and record the results, just to give you an idea. So here is a sample of the voice of yours truly reciting one of his favorite words (ahem!). I sampled myself using Amadeus II, with CD-quality settings, i.e. 16-bit, 44.1 KHz. (It should be noted that the iMic can sample at a frequency of up to 48 KHz, which is more than CD quality, and more that my Mac’s own audio-in port can do.)

I then saved the file as MP3 using the same settings as the ones used above.

As you can see, or rather hear, with this affordable equipment (and software), you can achieve very decent sounding results. You can easily use this to add your own voiceovers to your iMovie creations and other types of presentations.

The iMic also works with virtually any microphone, including unpowered microphones (microphone-level) and powered microphones (line-level). All you have to do is use the small black switch to specify the signal level of your particular microphone.

As I hope these few samples demonstrate, while the iMic might not match the quality level of high-end professional audio equipment (which I am not able to check, not being fortunate enough to own any), it certainly produces excellent results, which, in most cases and for most people, fully deserve to be qualified as “professional”.

Finally, if you are interested in using the iMic to digitize your old collection of vinyl LPs or audio tapes, then this little experiment demonstrates that the device is more than adequate for this purpose. All you need to do is plug your tape deck or turntable/receiver combination into the iMic’s sound-in port and switch it to line-level. After that, the main factors determining the quality of your analog-to-digital transfer will be the quality of your analog equipment (the tape deck, turntable, and receiver) and the quality of the original recordings. (You can also find third-party commercial software, such as Ray Gun, that can help you eliminate the unwanted popping sounds on old vinyl LPs and the unwanted noise and hiss on audio tapes.)

USB Audio Hub

To complete your digital audio set-up, with today’s cornucopia of USB devices, you will soon find that you need more USB ports than you have. You will then have to consider the purchase of a USB hub.

In that case, however, and if you intend to do any kind of audio recording and playback through your USB hub, you should know that, according to Griffin, most USB hubs fail to support USB audio devices (such as the iMic) in a satisfactory manner. This is the rationale behind Griffin’s decision to offer what it calls a “USB Audio Hub”.

This hub is, according to Griffin, specifically designed for USB audio devices. While I do not have enough equipment and enough information about potential audio problems with other USB hubs, I will simply note that, given that this hub supports up to 4 USB devices, includes a 6-foot USB cable, is designed to be stackable, and can work either as a bus-powered device (drawing its power from its USB connection) or as a self-powered device (it comes with its own 5-volt power supply) — for $39.00, a 2-year warranty, and the guarantee that it is fully compatible with USB audio devices, it is hard to find anything wrong with Griffin’s USB Audio Hub. (It also works with any other type of USB device, of course.)

During my few weeks of testing — actually simply using — the hub, I have not experienced any problems with audio devices. I have only experienced one small glitch. One morning, I noticed that the green light on the hub for the port to which my iMic was connected was not on. (The other three green lights for the other three ports were on and the devices were working fine.) I tried disconnecting the iMic and reconnecting it again. Still nothing. I tried switching ports, and it still didn’t work right. I tried plugging the iMic into one of my display’s USB ports, and it worked there. I plugged it back in the hub, and it wouldn’t work. I then tried unplugging and plugging the hub itself again, and then I heard the sound coming back (in my headphones connected to the iMic) and then the sound started “looping” repeatedly in the headphones. When I looked up on the screen, I had a kernel panic. Oops. My first kernel panic in about a year.

This being said, it is more likely to be an issue with Mac OS X itself than with the hub or with the iMic. I will keep investigating the matter with Griffin’s tech support, however (I took a picture of the screen with the kernel panic garbage on it), and will report back if I have any news.

Conclusion

All in all, using Griffin’s USB audio equipment is a very pleasant experience. In two words: it works. It doesn’t require additional software (although Griffin does provide a couple of Mac OS 9-only tools on this page). It is compatible with PCs running Windows 2000 or higher as well. And most importantly, it is definitely affordable. Since many people own Macintosh computers which no longer have built-in audio-in capabilities, it is good to see that a third-party product is available to fill the void and works as advertised.

My only (minor) quibbles include the design of the microphone/line-level switch on the iMic and the absence of some kind of indicator light. As for the problem with regarding playthrough support for the simultaneous use of the sound-in and the sound-out ports, let us hope that Apple will fix it in the next Mac OS X update. Other than that, the Griffin devices are great, and the price is most definitely right!