Pro Audio in a Box
Capturing high-quality audio in the field has historically meant arming yourself with a very expensive portable audio recorder. That may have changed with the latest recruit to Edirol's audio arsenal, the R-4 Pro 4-channel portable recorder and wave editor. This compact and well-built field recorder/editor features four XLR mic inputs, 80GBs of internal storage, a frequency response of 20Hz-40kHz and several popular sampling frequencies up to 192kHz at bit depths of 16 or 24 bits. With such impressive specs, we had to put this rookie on the test range.
Lock 'N Load
The R-4 Pro is compact and light. With padded soft case and wide shoulder strap, it would make even long field sessions relatively comfortable. The bag has good access to all input and output connectors on both sides of the unit through well-aligned Velcro flaps. Lifting the main bag flap exposes the front panel featuring the menu window and gives fingertip access to level knobs, record and all playback buttons. There's no easy way, however, to see or get to most of the top panel selector switches and controls, including the power button, without sliding the R-4 out of the bag, no small feat if you're fully wired.
The R-4 Pro is outfitted with all of the standard connections you'd expect and then some. XLR mic inputs are intuitively placed on the right panel (if you're right-handed), and we were glad to see locking Neutrik connectors, a must for serious field recorders. There are four discrete RCA analog line outputs for connecting external speakers or other audio equipment. The left panel hosts DC input, XLR type digital AES/EBU I/O, two flavors of USB 2.0 connection, time code I/O and a headphone jack. A Kensington security slot lets you limit portability to, well, just you.
Except for basic controls assigned to buttons, most of the R-4 Pro's features and settings are accessed thru menus. A 1-3/8"x 2-1/2" blue monochrome window gives ample screen area to easily work your way through the menus. The large tensioned shuttle wheel and interior scrub wheel give you fast access to menu choices. The scrub wheel can be a bit touchy when selecting among some options, but this is mostly an issue for the over-caffeinated.
You set input levels in two stages similar to a standard mixer, referring to real-time level indicators on the LCD panel. First you set the interior knob halfway for a 0dB level. Next you raise the outer-ring adjustment knob to adjust gain, or what Edirol terms "sensitivity." Even though this adjustment uses a knob, you have only 11 stepped sensitivities ranging from -56dB to +4dB.
For our first recording test, we played a 440Hz tone through a Mackie HR824 reference monitor, using an AKG C-414B ULS studio microphone powered by the R-4's phantom power. We set the R-4 Pro to its highest quality setting of 192kHz/24 bit and adjusted gain and levels by pressing and holding the pause button and pressing record. We recorded about 10 seconds of tone and played it back through the R-4 Pro's small built-in speakers to confirm the capture.
You have two choices for monitoring playback audio in the field: headphones or the built-in speakers; the monitor knob controls volume for both. The built-in speakers are quite small, and they should only be expected to confirm that you have recorded something. To assess quality directly from the R-4 Pro, you must rely on a good pair of circum-aural headphones (the kind that completely cover your ears). We found the playback levels to be satisfactory. We did, however, need to crank the monitor volume up to max (40mW) when we were outside near a road. Impacts on hearing aside, a little more power would be nice for special circumstances.
We recorded a narrator reading in a quiet environment for our second test, with the same mic and recorder configuration. With the narrator 8 inches from the mic and a pop screen in place, we set the R-4 Pro's gain to max (+4dB) to get a -3dB level. We checked playback with a pair of AKG K240 headphones and could clearly distinguish all the vocal nuances, overtones, transients, sibilance and fricatives that are a hallmark of a high-quality audio recording chain. Yes, we were impressed. Noise level was noticeable but very low and could easily be removed without much voodoo or impact on vocal qualities in post.
Finally, we tested the stereo built-in mics by recording an acoustic guitarist, placing the R-4 Pro about 18 inches from the guitar sound hole. At this distance, we had to set the gain and levels to their maximum settings. The resulting signal was noisy and not f final project material.
The built-in limiter works very well. Even with gain and levels set to maximum, we were not able to overdrive the recorded signal with even quick changes in source volume. Even without the limiter engaged, we were pleasantly surprised to hear a more tape-like overmodulation. Rather than the traditional digital crackle, we heard a more subdued distortion - distortion still, but much less objectionable.
Transferring files to your editing computer or external storage device is simple and fast using either of the two USB 2.0 connections. To get the most out of editing the high quality192kHz/24 bit recordings, you will need an audio card capable of handling this kind of data.
The R-4 Pro can also perform basic audio edits, such as trimming, cutting and merging files, but we found the small interface and unique commands required more effort than they were worth. We'd use the option of simply dumping to an external hard drive and editing when we get back. We did find it useful to set markers during recording and playback. Too often, you begin to record talent with several false starts. While continuing to record, with a press of a button on the fly, we were able to note the true take point.
The R-4 Pro can also record and send time code, which is a big asset when syncing to video. And the pre-record feature is a cool, potentially take-saving feature that uses a buffer to pre-record up to 29 seconds (depending on sample rate and bit depths).
So, if cost has been keeping you from getting high-quality audio in the field, the R-4 Pro is worth consideration.
AD/DA Converter: 24-bit
Sampling Frequency: 44.1/48/88.2/96/192kHz
Record/Playback Formats: .WAV, .BWF
Recorder Media: Internal 80GB hard disk drive
Recording Time Ranges: at 16-bit 44.1kHz - approx. 116 minutes; at 24-bit 192kHz - approx. 17 minutes
Analog inputs: 4 XLR connectors; Internal microphones (stereo)
Digital I/O: XLR type
Input levels: 11 steps from -56 to +4dBu br />R esidual noise levels: -90dBu (Sens knob at +4dBu, input level knob at minimum)
Total harmonic distortion (THD+N): 0.01%
Frequency response: 20Hz - 40kHz (0 to -3dB)
Phantom power: 48+/-4V /8mA (available 4 channels simultaneously)
- High quality portable recorder capable of producing professional level audio
- Poor access to some controls while in carrying case
A well-built portable audio recorder that rivals the quality of far more expensive units.
Brian Peterson is a video production consultant, trainer and lecturer.
425 Sequoia Drive Suite 114
Bellingham, WA 98226
One of the hardest parts about writing a review on an audio device is the lack of a standardized vocabulary. If you've flipped through the pages or browsed a website of any audiophile publication, you've no doubt found yourself surrounded by a cacophony of adjectives used to describe the audio experience. Words that, at minimum, have dual use, such as "clean," "transparent", "smooth", etc., are often used to give you a sense of inherent audio quality. Confounding the problem is that we all have different abilities to discern fine qualitative differences in sound. Age, genetics, experience and training, even gender all come into play. So while frequency, amplitude, distortion and noise can all be measured with test equipment and represented by numbers, most of us just want to know if the product we are researching will do the job, with maybe a little quality headroom to spare. With that, it may be useful for you to know that, in this review, we combined both the subjective interpretation of this reviewer (a mid-40's male with tested good hearing and more than 20 years of professional audio experience) with several quantitative tests that should help you answer your basic question, "Is this the portable digital audio recorder for me?"