Hands-On Review:A smarter approach to digital recording

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By E.A. Tennaway

With more than a year under its belt since Alesis debuted the HD24 at Winter NAMM 2001, this recorder still looks like the one to beat. Having played with a demo unit during the show, I was jazzed when Musician’s Friend shipped me a unit for review. A complete survey of the HD24’s capabilities reinforced my initial impression—this is a formidable recorder that overcomes just about all the drawbacks of hard disk-based recording, and does so at a very moderate price point.

It takes two to tango

The HD24’s two most significant features are its dual hot-swappable EIDE drive bays coupled with a control surface that feels familiar from the outset thanks to its ADAT-like controls.


The cost of EIDE drives has recently plummeted. 20GB units are readily available for less than $100. Keeping a stash of them around as permanent storage media is now an affordable alternative to constantly dumping projects onto tape in order to keep your hard drive clear for new recordings. An 80GB drive, at a typical cost of $250, stores six hours of 24-track audio or 8,640 track minutes. It’d take a couple dozen 40-minute 8-track ADAT tapes costing considerably more to accommodate that much music.


Affordability is just part of the HD24’s story though. Alesis’ ADAT File Streaming Technology (ADAT/FST) is designed specifically to handle the formidable task of efficiently storing and retrieving the huge files that are created by multitrack data. Many competing hard-disk based recorders use ordinary PC formats that are fine for handling relatively small data files. Faced with huge audio data files, however, these formats break up the data into many small files scattered all over the disk leading to dreaded fragmentation and resulting in seek-and-access-time slowdowns. ADAT/FST keeps all your song’s tracks in associated clusters for virtually instant access. Hit the Play button on your HD24 and the reponse is instant. By minimizing your drive’s work, Alesis’ audio-optimized approach means disks last longer and need less maintenance.


Alesis ADAT HD24 Hard Disk Recorder to enlarge

Better connectivity

Unlike some pricier recorders, the HD24 is ready for business straight out of the box. You get a full complement of 24 analog, 1/4" balanced TRS I/Os as well as 24 channels of digital ADAT Optical which provides up to 96kHz sampling rates. (At that rate, you’re limited to recording 12 tracks.) The 24-bit A/D and D/A converters with 128X oversampling keep the sound pristine. And just like ADAT, there’s a 9-pin connector for syncing up to five HD24s for an incredible total of 120 tracks. A terminated BNC connector lets you sync to external word clocks. The recorder automatically syncs to incoming digital signals on its optical connectors.

Alesis ADAT HD24 Hard Disk Recorder to enlarge

Better backups and transfers

With its two-drive setup, backups are a breeze. Just send the data from one drive to the other and you’re done. There’s no need for a second machine. But if you want to get your project into your computer or network, that’s dead-easy too with the HD24’s Ethernet port. You can even upload and download files via any software with FTP capability such as Netscape or Explorer. These web browsers detect each Song as a file folder. Once opened, the original tracks will appear as individual files in either .WAV or AIFF formats ready for import into your virtual mixing software. (Web browsers tend to be pokey, so if you’re dealing with large files and/or slow connection speeds, you’ll want a standalone FTP client application such the freeware WSFTP for PCs or Fetch for Macs.


Of course, if you already own an ADAT-compatible recorder, Alesis supports backups and transfers that way too via the HD24’s three sets of ADAT optical jacks as well as its ADAT Sync In and Out ports. That means you can transfer 24 sample-accurate tracks at once to any ADAT system, computer interface, digital mixer, or other hard-disk recorder in real time.

Are we rolling, Bob?

The HD24 ships with a 20GB drive installed in one of the two caddies. Minutes after getting the recorder out of the box and glancing at the quick start guide, I was up and running. The recording process itself is exceedingly straightforward. Stick a caddy-mounted drive in either bay, select that drive, arm the track numbers you want to record onto, hit Record and Play, and you’re off to the races. The 24-channel fluorescent meter bridge located above the drive bays keeps you posted on what’s being recorded to the disk. To the right side is a large alphanumeric display, the transport controls, and the function/edit keys.


Alesis ADAT HD24 Hard Disk Recorder

Editing is also a no-brainer. You can easily scrub any or all channels. Just scrub to your edit in and out points and perform a cut, copy, or paste to copy regions or whole tracks. Don’t like the result of your edit? No problem. Depending on the size of the edit, the HD24 supports up to 99 undos.

Inserts are also easy since you can copy and paste data into different songs or hard drives using mark points. Each song may have up to 25 locate points associated with it (zero, plus 20 standard points, two punch points, and two edit points). Seven points are accessible from the front panel. A total of 1,600 points are automatically stored and retrieved with songs. A Set Locate button allows you to set points on the fly and you can assign an eight-character name to each for keeping things straight.


If you’ve been considering making the jump to hard-disk based recording, the HD24 is a versatile and cost-effective way to join that club.

Features & Specs



  • 24-track, 24-bit recording
  • 44.1 & 48kHz internal sampling
  • Simultaneous 24-track record/playback
  • Supports 12 tracks at 88.2 or 96kHz
  • Dual recording bays
  • Uses affordable EIDE drives
  • Includes one 20GB drive & 2 caddies
  • Easily integrates into ADAT systems
  • 24 analog I/Os
  • 24 ADAT Optical I/Os

  • ADAT Sync I/O
  • MIDI I/O
  • MTC output
  • Ethernet connection
  • FTP-transfer capable
  • Editing includes cut, paste, copy
  • Up to 99 levels of undo
  • Intuitive record and edit interfaces
  • Includes all hardware and connectors
  • Includes Alesis LRC remote control