UPDATED 7/18/2007 VERSION

(This review is being written/edited; e-mail suggestions welcome)

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This review is narrowly focused ONLY on deck operational features, ease of use, consistent recording ability/quality, and design fault issues related to stereo-surround field recordists with direct connected mics; issues usually not discussed in commercial magazine reviews. In other words, how suitable is the MT24/96 as an 'all-in-one' deck solution for the professional field recordist?

Introduction: After many years of waiting, an all-in-one affordable, compact, new technology (NT) audio portable recorder has arrived in November of 2005 taking form of M-Audio's Microtrack 24/96. Although maybe NOT the perfect deck for those wishing seamless SPDIF input at all sample rates, this deck is sufficient to have hit the target for microphone field recording requirements, at least with most recently updated firmware revision 1.4.6 installed. Because of nonuser replaceable lithium battery running for up to 4 hours, Microtrack seems more practical running on externally connected USB power supply.

(NOTES: Newer firmware versions now reliably performs almost seamless recording by automatically creating a new file within 5 seconds as recording crosses the 2 GIG file limit.

TRS inputs have on/off (up to) 24 volts phantom power feature that's a bit weak/noisy. Most find best performance by externally powering condenser type mics.

Very compact Microtrack 24/96 allows many WAV/MP3 recording modes with select-your-desired-quality/file sizes for any size/type compact flash card storage. This includes various flavors of MP3 lossy encoding for reduced quality/file size, and high definition audio 16/24bit depth at 44.1, 48, 88.2, 96K sample rates.

Microphone audio input is also expanded over miniDAT with having both 3.5mm stereo mic jack (+5 volt for electret mic) at two gain settings, and (+12-30 volt) phantom power dual balanced TRS 1/4 inch line/mic with 6 gain selections.

Surprisingly, all analog inputs on this deck have tested to be adequately quiet (tested with phantom power off) and of good wide bandwidth quality for at least 16bit depth mic input requirements. However, suggest best for 24 bit depth recording adding external mic preamplifier outputting analog line level for lowest noise higher definition recording requirements.

Internal lithium-ion battery is NOT user replaceable; a definite shortcoming for extended all-day use and for remote location field projects. However, using an external powering accessory, like the BC-MT power sled, keeps MicroTrack operating with fully charged internal battery for unlimited field recording time.

These decks should now be shipped with latest firmware v1.4.6 installed, so you might check your MT deck for having this version, or if additional updates became available. Resource rich forum group for portable recording gear and live sound recording interests is www.taperssection.com

Summary: As-is, Microtrack 24/96 deck seems very good to excellent as an all-in-one recorder for at least self-[powered microphone input field recording, and for DSM™ stereo-surround mics only with passive PA adapter, or use external preamp for optimum quality recording.

Two VU indications; (slower responding) average level and faster peak signal indication with slow decay indication. Outdoor visibility is quite good, and back light works well enough in low lighting.

(NOTE: Outdoor LCD display visibility is ONE feature total lacking in Edirol/Roland's otherwise excellent R-09 flash deck.)

VU indication is accurate, but feels too slow. Is Microtrack's one feature needing improvement. With firmware version 1.2.0 and later (latest is v1.4.5), there's far less feeling of being 'out-of-touch' with recording dynamics.

The peak indicator response has been improved to to show faster peaks, and holds the peak reading for sufficiently long time for easy reading. However, average 'filled bar' indication while slightly improved, still seems too slow. VU indications still need to update at least 3 times faster for a more professional VU 'feel'.

Add dB scale to the MT 24/96 VU

Yes, it's disappointing M-Audio omitted a dB VU scale. While not fatal, most find dB marked VU scale is at least helpful to gage needed headroom for avoiding clipping, and adjusting for adequate recording levels.

(NEXT TIP)

Practical adhesive label showing the missing dB scale markings is FREE if lucky and/or having courage for accepting challenges requiring hand-eye-brain coordination.

If lucky to have Brother 300dpi USB connected TZ label printer, and want to print this label yourself and for others, then HERE is the design file for free download, compliments of Sonic Studios.

For those not so lucky with having the printer, but in US or Canada, and still wanting the challenge of applying a much needed very tiny label, get the FREE 3-line printed label (as shown on the right) by sending #10 or smaller self-addressed -postage paid envelope, to: Sonic Studios, DB LABEL OFFER, 1311 Sunny CT., Sutherlin, OR 97479 (USA)

NOTE: Label requests arriving without addressed envelope and/or full 1st Class postage will be vaporized!

The MicroTrack 24/96/96 deck has two types of microphone inputs, with one serving also as LINE input.

The first input is consumer 'mini-deck-typical' 3.5mm stereo jack, limited with ONLY two mic gain settings ("L" and "M or H").

The second input is for professional dual 1/4" balanced TRS plugs serving up one LINE level setting ("L"), and 5 mic gain selections ("M", "H", and +27 dB boosted "L","M", "H").

Chart is analog gain settings; 8-10 dB gain jumps with each successive combination; rebooting may be necessary after switch adjustments or until firmware fixes faults

The MicroTrack 24/96 has two REC Level adjustment up-down buttons that can be selected to independently, or ganged together (stereo mode) adjust the recording level as displayed on the VU indication bar. However, the REC level adjustment is different from the usual, it is actually a GAIN control with ONLY 12 dB of adjustment range.

In other words, the recording LEVEL adjustment is actually a 'fine gain adjustment' with unexpected limited range adding 12 dB adjustment to choice of (L/M/H) gain switch. There is NO ZERO (full down)or 'no-signal-adjust-to-setting' like usually found in recorders with real mechanical type knob or digital up-down buttons.

However, although at first awkward, this scheme does work, and allows a continuous( -54 to +3 dB) input signal range ability.,

The limited 12 dB up-down REC level adjustment in concert with the 8-10 dB stepped L/M/H switch does give the MicroTrack a continuous wide (TRS) input range and seems a definite plus or strength to balance the more complex gain selection process for controlling REC levels.

In contrast, the minijack input is simply gain limited to mostly work with higher signal output electret condenser microphones mics, but not as compatible with dynamic or lower output DSM mics.

The Microtrack's low/medium/boosted dual TRS inputs are adequate for most types of microphones, and is clean for moderate 1-2 volt RMS professional type LINE input levels. An attenuation pad may be needed for professional mixing boards, external preamplifiers, and directly connected externally powered 48-100 volt condenser mics.

Newest, firmware 1.2.0 eliminates the need for stopping the recording in any way with every change of the L/M/H switch setting! So unless the HOLD is actuated, recordists can switch input sensitivity on-the-fly while recording. MicroTrack now has ability to allow REC level VU indications while in REC Pause mode.

*(1) NOTES: dBv = dBm = 0.775 volt RMS = 0 dB reference level.. REC level adjustment is set full left (at minimum). The signal now has 12 dB less (recording) gain than if the REC level adjustment is set 'full-up' where 12 dB MORE signal sensitivity than shown in the chart is possible.

Example: Chart indicates 3.5mm jack's most sensitive setting is "M (or H") with -25.2 dB (42.5 mv) needed to produce full scale VU. Since REC Level adjustment is at minimum for this measurement, anything LESS than 42.5 mv is OK to input and NOT OVERLOAD CLIP DISTORT. A STRONGER signal will require setting change to "L" for 8-10 dB of required headroom margin. REC adjustment may then increase up to 12 dB of additional gain as often necessary when VU indication (recording audio signal) shows too low.

Microtrack 24/96 topside controls buttons are a good size, and easy to find and operate. Mostly a very nice design.

Impressively designed-in tactile feel (molded bumps, dimples) before, and during finger actuation with a solid felt click gives ability to work this deck blindfolded(wearing monitor headphones).

Menu-selected 'Stereo' mode locks REC level buttons together for automatically precision channel balance at all adjustment settings.

When Microtrack 24/96 topside button controls are pressed (actuated), they also produce a (pure mechanical) LOUD click sound; clever design to actually 'hear a button push.'

I supposed clearly hearing a button click helps to assure that just enough finger pressure is applied; seems a good feature, and maybe extends button service life with less misapplied hard pressing. The loud clicking sound definitely helps when when wearing thick gloves.

However reassuring hearing a control button click sound, the MT24/96 deck is a PORTABLE RECORDER, often used with directly connected microphone(s). The button clicks are loud, and easily heard (and recorded) at a 3 meter distances in a quiet ambient.

Many of the better mics used for stereo-surround recording are very good at documenting 'click-sounds' into the recording!

Pushing the right-side silent panel located 'navigation' button pauses the recording so button (and other) sounds are not recorded, however, in pause mode, VU indication also stops.

The delete (DEL) button usually needs two pushes to actually delete a file, but is too easy to accidentally actuate when handling the (unlocked) deck. Addition of a permanent molded-in button guard is suggested; same problem with REC button.

Recording Level adjustment buttons have nearby green and red LED indication of minimum signal activity and overload clip.

Green LEDs indicate (very low) REC signal activity. These LEDs show the presence of most any REC signals not (yet) showing VU indications.

Red CLIP LEDs are responsive to indicate REC overloads.

TIP: Best to place some sticky-side Velcro (as shown at left), makes DEL actuation less easy. (Next tip)

Record button starts and ends the recording process. Recording button functions immediately to start the recording from any non-recording state, even if in the menu display mode.

Pressing the Navigation Toggle switch (not shown in view at left) while in REC mode will PAUSE/RESUME the recording

REC LEVEL adjust buttons and NAV switch now work consistently with latest firmware. Giving stable one-jump adjustment steps with each 'click' regardless of press-release method.

Holding down the REC LEVEL adjust button(s) activates a 'fast repeat' mode for multiple adjustment steps in a short time. 'Fast repeat' mode is activated with little delay, so maybe practice getting single steps.

Volume up-down control simultaneously adjust both headphones and (surprisingly) LINE level outputs. Usually LINE level is NOT so adjustable

Noise spectrums of minijack (MJ) and 1/4 inch (TRS) analog inputs

(All inputs 1000 ohms 1% metal film resistor loaded to ground unless noted; 24bit/88.2K sample rate data)

Linear View

(at minimum recording adjust level)

Minijack input

LOG VIEW

(at maximum recording adjustment level)

LOG View

(at maximum recording adjustment level)

(at maximum recording adjustment level)

NOTE:

When compared, +27 dB boost mode (-23 dB yellow) shows lower low-bass to mid-high frequency band noise than lower mic gain setting (-14 dB violet) operating without +27 dB boost.

NOTE: When compared, +27 dB boost mode (TRS+27L yellow) shows lower low-bass to mid-high frequency band noise than lower mic gain setting (TRS-H green) operating without +27 dB boost.

(LOG View)

(at minimum recording adjustment level)

Dual TRS-H vs. MJ-L input at ~equal gain

NOTE: Lower noise MJ input mid-bass to high frequency noise as compared to TRS mic gain set input.

(LOG View)

NOTE: TRS MIC level input with +27 dB boost "L" setting shows lower low -bass to mid-high frequency noise as compared to MJ input

Dual TRS+27dB boost-L vs. MJ-L input at near equal gain

USING EXTERNAL MIC PRE INTO TRS ANALOG LINE INPUT

PA-24XP MIC PRE CONVERTS MICROTRACK TO STELLAR PERFORMANCELOW-NOISE, HIGH DEFINITION DECK

NOTICE TOTAL REDUCTION OF LOW/HIGH FREQUENCY NOISE SPIKES Vs MT PRE

(REC level at maximum setting)

(PA-24XP input loaded with 1000 ohms to ground as was done for all graphs in this series)

The use of an external mic preamplifier of most compact size gives comparable audio performance to much larger, more costly, and far more power hungry 'all-in-one' decks (like excellent, and 'fuller featured' Sound Devices Series 7) for DSM stereo-surround 2-track recording.

200+ hours AA battery running time of PA-24XP, and 500+ with less featured PA-3SX-P configured with Microtrack deck being powered on external USB power sled allows continuous deck running time of up to 45 hours on common alkaline C and worldwide stocked D cells.

The external preamplifier configuration with Microtrack 24/96 deck is an affordable pocket sized solution for high definition 2 track, easily powered portable recording package.

MISC.: One needed improvement for having a more refined design is this deck's printed circuit board (PCB).

In my opinion, this board likely needs to go back to engineering for a redesign to eliminate switching power supply noises leaking into the analog stages (as seen in the above noise graphs of deck's internal mic level inputs).

MicroTrack power was read by connecting +5 volt, 600 ma. external BC-MT power sled, monitoring the sled current with deck operating modes.

The USB connector (located at the decks bottom side panel) charges the battery from supplied universal AC adapter, or when deck's USB port is computer connected.

Using an external USB connected power source like BC-MT or MD-MT power sleds keeps battery fully charged with deck operating

MT4 Series USB Power Sleds are very advanced Microtrack powering solutions

MT4 is a higher costing, higher performance Microtrack external charging/running solution.

Using only 4 C or D size alkaline cells, a special boost regulator extracts over 100% battery capacity for exceptionally long running times.

Full details on the External Power Systems CHART

With DECK OFF, plugging in charger shows sweeping battery icon indicating active charging.

Battery charging indication(s) seems a bit confusing. Difficult to tell if battery is fully charged or charging. With deck booted up, and charger connected, the battery icon seems forever at 'CHG' regardless (see icon at right).

Latest firmware v1.4.3 addressed several issues of concern.

First was knowing if the internal battery needed additional charging. Past operation allowed immediate 'top-off' charge cycles, even if just charged up a few moments ago.

Past firmware allowed good chance to shorten battery life from OVER CHARGE with quickly repeated 'top-off' cycles.

Kingston Standard Series should fine work for most moderate audio recording rates

SanDisk ULTRA II Series

GENERAL NOTE: Tested OK for all Microtrack deck recording modes. These CF cards are Type 1 +45x speed, and now available in 8GB size. Recommended for reliability and low cost.

CF/1024-S 1 GB Compact Flash Card (SLC) (50x)
CF/2GB-S 2 GB Compact Flash Card (SLC) (50x)
CF/4GB-S 4 GB Compact Flash Card (SLC) (45x)

NOTE: Microdrives greatly shorten battery run time. Usually by half as compared to CF.

TIP: Best to ALWAYS freshly format the CF card INSIDE the Microtrack whenever removed from the deck for purpose of transferring files with a separate card reader.

Also a very good idea to freshly format the card even if left always inside the deck. Do this every time all needed files have been safely transferred and all remaining files are to be deleted. Reformatting the CF card erases ALL stored files and allows most reliable new file creation by the deck. (Next Tip)

NOTE: Use ONLY non-accelerated types of memory for audio recording purposes. Advanced or 'extreme' types use a form of burst mode best for camera files, but burst modes may disrupt reliable audio recording and these types flash should be avoided.