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Sunday, July 17, 2011

Home Recording Review/Benchtest!
Tascam DR-680 High-Resolution
Eight-Channel Mixer/Recorder


Brevis...
Price: $1,399 retail; $895 street
Likes: multi-track mixing, A/D, preamps
Dislikes: smallish LCD screen
More info: TASCAM DR-680


By Tom Jung

Smaller, lower price, and better sounding. That certainly is the trend with standalone audio recorders these days. With its $1,000 HDP2 stereo Compact Flash recorder now more than five years old, TASCAM has taken advantage of technology advances for multichannel audio recording/playback and given us the DR-680, an eight-channel FLASH recorder for under $900 on the street.
Don’t be fooled by its price; the DR-680 is a recorder that is capable of doing truly high-end professional multitrack work. Not all that long ago a high-resolution eight-track recorder in the $900 street price range was unthinkable — especially one that sounds this good.

Features
Priced at $1,395 retail ($895 street) the DR-680 is an audio marvel, recording up to eight channels of high-resolution PCM audio to SD/SDHC Class 4 or greater media cards up to 32GB. The DR-680 covers bit depth and sample rates up to 24/96 with all eight channels running — and up to 24/192 in the stereo mode. The standard PCM sample rates are covered — 44.1 kHz, 48 kHz, 96 kHz and 192 kHz — but no 88.2 kHz or 176 kHz. The AKM A/D-D/A converters are the same ones used in the highly regarded DR-100 stereo portable recorder reviewed on EAN last year.
If recording time is more important to the user than audio quality, the MP3 file format is available with bit-rates from 96 kbps to 320 kbps; the former rate yielding over 370 hours of four-track recording time with a 32GB card.
The DR-680 is perfect for small live recording gigs or home recordings where you want simple set up, record and mixing with more than two microphones. The DR-680 form factor is perfect — not too small, not too big — considering how much connectivity it offers. At 8-inches wide by nearly seven inches deep, the recorder features balanced/unbalanced/digital connections, headphone amp, top-mounted and front panel function buttons in a stout aluminum-framed package.

Yes, there were subtle audio differences that I still preferred with the original DSD, yet this $900 PCM multitrack recorder, that runs on batteries, captured much of the essence, detail and imaging of the master recording.

The DR-680 is powered by eight AA batteries or the included AC “line lump” 12V power supply. Batteries are easily accessible via the sliding bottom lid. Accessories include a carrying strap. TASCAM also sells a waterproof storage bag.
Connecting the TASCAM to a PC or Mac is a snap, using the supplied USB 2.0 cable. The PC recognizes the unit as a mass-storage device, and no driver software is necessary. If you have an external SD drive, you can also remove the SD card from the recorder and pop it straight into a computer. Input options include six balanced mic/line jacks (four are XLR/TRS 1/4-inch combo jacks; two are TRS 1/4-inch only), stereo SPDIF digital connection, and a live monitor mix can be selected to feed channels 7 & 8. All six microphone inputs have phantom power, switchable in pairs — along with individual channel gain ranges. Individual mic trim is software controlled in half-dB steps by simply selecting the dedicated front panel channel button and turning the knob, just like an analog control only with more precision.
The internal digital mixer has both level and pan controls so a quick six-to-two mix is a snap — whether you do it during recording or back at the ranch. A solo function is also provided. However, it is more of a PFL (pre fader listen) since it is mono and does not follow the panning. For output options, you have six individual unbalanced analog line jacks available — as well as digital in & out for channels 7 & 8 all on RCA jacks. The digital in/out jacks also serve as a cascade sync function that allows the transports of multiple DR-680 units to be controlled by a single master unit. Pretty sophisticated stuff for so little money.


The LCD screen is backlit and has 128 X 64 pixel resolution, which initially seemed undersized. But after using it for awhile, I deemed it adequate. The smallish, graphic bar meter display also has no reference legend. You have to figure out the peak levels so you don’t get digital distortion, as it has only a simple line you must not exceed on the meter.
The DR-680‘s operational software, in conjunction with the push-button and rotary controls, is very intuitive; you can easily set up the project, make recordings, mix and transfer the finished audio project to PC — without ever consulting the manual.

The DR-680‘s operational software, in conjunction with the push-button and rotary controls, is very intuitive; you can easily set up the project, make recordings, mix and transfer the finished audio project to PC — without ever consulting the manual.

For those that need the ultimate in syncing duties, the DR-680 does not have timecode generation or reading capability. But you have to sacrifice something at $900 bucks. If you want timecode, move up to TASCAM’s audio-for-film, high-end location recorder, HS-P82, for those high end functions and features.
It also should be pointed out that the DR-680 is designed to record separate audio tracks for stereo down mix. It does not allow overdubs or filling in extra tracks later after the original recording has been made.

The audition
Although one can use a variety of available computer digital interfaces to record multiple tracks, computer audio setups are often cumbersome and overly complicated. Standalone recorders like the DR-680 are extraordinarily focused audio computers and are often easier to operate. And that ease of use is one of many reasons that EAN Publisher/Editor John Gatski and I like the DR-680.
Most of the live musical recording for this review was done at John Gatski’s home studio, while I focused on the DR-680’s converter quality by recording various bits of analog to PCM music and dubbing some of my own original DSD masters from the DMP label.
Mr. Gatski recorded a number of acoustic guitar recordings — up to four tracks — with a Shure KSM-141 condenser, an ADK vocal, and two Audix SCX-25 microphones. His take on the TASCAM was that the guitar and vocal recording quality was clean and detailed (as high-resolution audio should be) in 24-bit/96 kHz mode. Mic preamps were clean and quiet, and in comparison to the TASCAM HDP2 midsize stereo recorder and the DR-100 portable stereo recorder, Gatski said the A/D quality of the DR-680 is virtually identical — which means it is quite good.
He said the DAC playback quality was about on par with the other machines as well, though the DR-680 is slightly smoother on the top-end than the five-year old HDP2, in which the converters are a couple of generations from current. (The current HDP2 has the latest generation AKM A/D-D/A converters.)


The headphone amp is good with the ability to drive AKG headphones. However, Mr. Gatski and I noticed a strange audio “buffering” sound when changing the headphone level as the music was playing. Once the level was set at the desired level, the sound was fine. The outboard speaker works okay as a general monitor for the audio, but it is mono and rather low-fi compared to the headphone or line output.
The DR-680’s A/D and D/A audio quality conclusions were further cemented by my subjective testing. I set up a most challenging audio evaluation for the DR-680 (or any PCM converter) — a direct analog-to-digital dub of my original multitrack DSD jazz recordings done in the 1998-2003 time frame. I copied the DSD surround production masters from my Sony Sonoma DSD recording/edit system to the DR-680. With six XLR cables I connected the output of the Meitner DAC8 MKIV DSD D to A converter (whew!) to the six balanced inputs of the DR-680 set to the max resolution of 24/96.
I copied master DSD of Warren BernhardtAmelia’s Song (the most open, transparent recording that I ever made). It was made using six microphones into six mic preamps — straight into a Meitner ADC8 A-to-D converter with no console or signal processing.
After the dub procedure, I plugged the unbalanced RCA outputs of the DR-680 into the Meitner Switchman multi-channel pre-amp which is connected to six channels of Bel Canto power amplifiers driving SLS ribbon monitors.

Input options include six balanced mic/line jacks (four are XLR/TRS 1/4-inch combo jacks; two are TRS 1/4-inch only), stereo SPDIF digital connection, and a live monitor mix can be selected to feed channels 7 & 8.

As a DSD fan and with my familiarity with this recording, I expected the playback from the Meitner to be much better than the budget TASCAM PCM A/D-D/A playback. But in truth, the PCM copy of the DSD tracks held up remarkably well. Yes, there were subtle audio differences that I still preferred with the original DSD, yet this $900 PCM multitrack recorder, that runs on batteries, captured much of the essence, detail and imaging of the master recording. And it played it back with good results as well. If you play the DR-680 recording through high-end D/A converters the result is even more impressive. This recorder has an excellent A/D converter.
Other than the small display, I cannot criticize the DR-680. Even the battery life with all channels being used is pretty good. Headphone amp is good, powering hard-to-drive AKGs with smooth output. Even the physical construction is fairly robust, as I got tangled in a line cable and sent the unit flying to the floor; no mechanical or cosmetic blemishes.

The verdict
For the money, the TASCAM DR-680 does multichannel recording with quality that was unheard of in my days of full time PCM digital recording. If you consider its features, performance and utility, the TASCAM DR-680 is a steal. Its range of uses include home recording of musical instruments — all the way to a professional live multitrack session at a club venue. I told the boss to give it an Everything Audio Network Stellar Sound Award. He heartily agreed.

EAN Publisher/Editor John Gatski also contributed to this review. A professional audio engineer for almost 50 years (Sound 80, DMP Records), Tom Jung reviews home theater, audiophile and high-end recording gear for the Everything Audio Network, testing products from his home studio in North Carolina. He can be reached via email at tjeverything.audio@verizon.net


©All original articles on this site are the intellectual property of the Everything Audio Network. Any unauthorized use, via print or Internet, without written permission is prohibited.



EAN BenchTest!

TASCAM DR-680

by Bascom King


The TASCAM DR-680 is a member of the multi-channel compact class of digital recorders. This one can record up to a bit density and sample rate of 24/192 in stereo, or up to six channels at 24/96. Although the DR-680 unit has digital I/O and analog I/O, most end-users are going to download the finished recording to a computer, so we decided that the A/D measurements were the more important measurement parameters, though we did make A/D-D/A calculations as well.

Frequency response at 0 dBFS at a sample rate of 192 kHz is shown plotted in Fig. 1 for analog inputs 1 & 2 and for the digital output for both the line input and the mic inputs at the high gain setting. Surprisingly, the flatter response is for the mic input here. The channel tracking is so good here that one can’t see any difference between the channels at this graph vertical resolution.

The analog output response for the same input conditions is down a bit more at 90 kHz due to the D/A filters and is at about –10 dB. The low frequency response was down about 1 dB at 10 Hz. When the response was measured at lower sample rates of 96 & 44.1 kHz, the response shape was much flatter up to the filter cutoff – a result I usually see in digital audio device measurements.



An interesting and revealing measurement is in the distortion vs. level of a 1 kHz tone in the digital output with input signals applied to the line inputs. Fig. 2 shows this plotted in a 20 kHz measurement bandwidth and at a sample rate of 192 kHz. This indicates a S/N ratio of 100 dB. This is quite good for an integrated all-in-one, rather inexpensive recorder/player (though the best converters can exceed -115 dB). This same test on the analog outputs showed some lumps upwards in the curve caused by some D/A misbehavior at sample rates of 192 & 96 kHz from –5 to –30 dBFS. In these deviations, the amount of distortion was still better than –83 dBFS. At sample rates of 48 & 44.1K, the curves were smooth like in Fig. 2.



S/N ratios at the digital outputs for sample rates of 192 kHz, 96 kHz, & 44.1 kHz and in a measurement bandwidth of 20 kHz were 100.0 dBFS, 95.5 dBFS and 95.5 dBFS respectively. Dynamic range measurements for the same sample rates were 102.8 dBFS, 98.1 dBFS, & 98.0 dBFS. Finally, for the digital output, the quantization noise measurements came out to be –96.0, 93.6, & - 93.6 dB. Again, these are very good measurement results.

In general, the same measurements at the analog outputs were just a few dB worse. When going through the mic inputs at the high gain setting, measurements were yet a few more dB worse for both analog and digital outputs, but still well into -90 dB+ range. That is still pretty quiet.

Adjacent channel separation was quite similar in both directions for both digital and analog outputs. What was a bit odd was that the nature of the separation was typical rising with frequency for the mic inputs but had a characteristic of rising at low frequencies for the line inputs.

All in all, the DR-680 performs pretty well on the bench — especially for its small size, features and what it costs.


Bascom King is owner and chief technician for BHK Labs in Santa Barbara, Ca.

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