Alesis HD24 24 channel Digital Hard Disk Multitrack Recorder
Last Update 05-26-2025
In keeping with my "analoguediehard" moniker, when I was in the
market for a multitrack recorder I was determined to acquire a real
analog tape multitrack machine. Now THAT's a diehard.
Fortunately my musician friend talked me out of it, as analog tape
recording was going out of fashion and analog tape machines and raw
tape were no longer in production. Buying a used analog
machine was risky with unknown wear on tape heads that are no longer
being made. Although thirty years later today, analog tape is back
in manufacture and "old" is now "new"...
The Alesis ADAT multitrack machines were popular, but I didn't want
to rely on VHS media cartridges and they were only eight track. Plus
they also had the risk of head wear and the quality of VHS tapes
leaves much to be desired (dropouts, etc). At the time the
HD24 was the newest multitrack in the Alesis line, and 24 tracks of
digital audio was stored on 3-1/2" IDE PATA hard drives. By the time
I acquired the HD24, Alesis had changed owners and all the studio
products were being discontinued. One essential item is the
drive caddy, the first accessory to be discontinued. They were a
ViPower product with modified wiring that only worked with the HD24
and those were gone too. So the only drive caddies I ever had
were the two that came with the machine. If you don't have the
caddies when buying a used HD24, you can't record anything.
Turns out the HD24 was the right product for me. It has a pretty big
feature set. The HD24 file format is the ADAT/FST (File Streaming
Technology) that is optimized for latency free fragmentation free
audio recording/playback (also meaning that the hard drive cannot be
read directly in a computer). It can record each channel in 24-bit
depth 128x oversampling at 44.1k or 48k sample rate, or 12 tracks
max at 88.2k/96k sample rate if the option is installed (the HD24XR
pictured above includes the 88.2k/96k option). Songs can be
configured for 2, 4, 8, 16, or 24 tracks. You can name songs (but
not tracks) and organize the songs in named folders, and there are
twenty five locations per song. Aside from a few standard locations
(IE punch in, punch out) the locations can be named which is very
handy for jumping between verses, chorus, and solos. Unlike tape
based systems, jumping between location points on a hard disk system
is instantaneous.
Editing is much easier in the digital domain than analog or the ADAT
VHS format. Tracks can be copied, cut, pasted, moved, or inserted
using the front panel with multiple levels of undo. The key thing is
to make sure the right track(s) are selected and your location
points are accurate. You can copy/paste tracks between songs. Tracks
can be looped, auto record and auto return are available for
punch-in, and punch-in can be rehearsed. Read the user manual
to get familiar with the features and the front panel interface,
with repeated use it will become intuitive.
The rear panel has 1/4" TRS jacks for all 24 inputs and outputs. The
inputs are balanced, but the outputs are "pseudo-balanced" meaning
you have to be cautious with cable length and input impedance on the
receiving device. I opted to configure a 48 point patchbay solely for the
HD24 which meant building 48 cables between the HD24 and patchbay
(24 inputs, 24 outputs), then building bundled cables of 24 send
and 24 return lines to/from my mixing console. I decided on a
standardized mixer channel allocation for music instruments, which
means I don't have to shuffle cables around. Building the cables was
a lot of work, but well worth it.
Digital transfer of the audio tracks is a problem today. There's an
ethernet port for transferring digital audio tracks to a computer or
the internet (the HD24 functions as an FTP server), but the protocol
is a very old TCP/IP 10/100 base-T network port that is VERY slow
with audio file transfers (a 24 track song can take over an hour to
transfer). Unfortunately this can't be improved with a firmware
change as the TCP/IP port is fixed in hardware. Currently I can only
transfer to my Windows Netbook as I have not yet succeeded in
finding an FTP app that works with the HD24 on macOS (I abandoned
Windows years ago). I have always noted that new music gear uses
computer media or I/O that is a generation behind the computers at
the time.
The only option for digital transfer are the ADAT optical I/O.
There are three ports each handling eight tracks. The ADAT
protocol may be over twenty years old, but it is a robust protocol
and is still in use today. Very few interfaces have more than
two ADAT optical I/O ports, one of the few recent ones is the RME
Digiface USB with four ADAT I/O ports. This RME
product has been around a long time, there's a lot of happy owners,
and the company has an excellent record of maintaining their drivers
as OS versions advance (something that is sorely lacking
today). From reading the user manual, it appears I can record
HD24 digital audio into Logic from the Digiface (albeit 16 tracks at
a time). I'm about to order one, will report back later.
There is a 3rd party tool set called HD24Tools that includes a tool
that allows a computer to read a HD24 hard drive, but the tools have
not been updated in a long time and may not work on modern
computers. I'm not risking that option.
Today, IDE PATA hard drives are no longer made so you have to find
NOS or used ones. One day I was in the IT office at work and had
noticed a pile of PATA hard drives. They were replacing old
computers and the hard drives were surplus and destined to be
disposed. I asked if I could take the hard drives for personal
use and explained that I would use them in a digital multitrack
recorder, whose format process would completely erase forever any
company proprietary data on them. The office gave them to me - what
luck! I now have plenty of hard drives to last me more than a
lifetime, all of them are reputable brands (Western Digital, Maxtor,
Seagate), they date before the notorious "one year warranty" drives
with short life, and some of them were very large capacity (160GB)
which have been handy for recording four hours of live music.
Alesis packed plenty of control options on the HD24. Included
is the wired Little Remote Control (LRC) for transport control and
limited location select, loop start/stop, and punch in/out.
You can't use extension cables with the LRC or it will stop
working. Alesis made the Big Remote Control option (BRC) for
its ADAT machines; it will work with the HD24 but some ADAT
functions on the BRC are no longer relevant for the HD24, and if you
use the BRC as the master clock the HD24 doesn't sync using 44.1K
sample rate (use 48K). If you buy a used BRC, make sure the
sale includes the multicore cable for the ADAT ports! I had to
make my own cable, referring to the patent US#5,541,781 for the
wiring details.
A BNC Clock port allows the HD24 to sync to an external clock as a
slave, or as a master clock to external devices. The HD24 will
also sync to MIDI Time Code. The really cool feature is MIDI
Machine Control (MMC), which allows your MIDI sequencer or computer
to control the transports on the HD24, or the HD24 to control the
transports on the sequencer or computer. I actually got this
to work on my MIDI computer running Cakewalk Pro Audio on Windows
for Workgroups, an OS that dates to 1993! This allows me to
work at the MIDI controller and MIDI computer while controlling
play/pause/rewind/fast forward on the HD24, or sitting at the mixing
console near the HD24 which controls the sequence on the MIDI
computer!
I'm not going to recite the complete feature list, suffice to say
that it is pretty comprehensive.
The HD24 is a great product, still widely used today and owners
share a lot of tips on discussion forums. Mine has never
malfunctioned since I acquired it in 2007. Some would say that
today's DAW and audio interfaces have rendered the HD24
obsolete. Well, yes and no. You can save money buying a
used HD24 but options are no longer available and you have to look
for PATA hard drives. However, as computer OS versions
advance, DAWs and audio interfaces can stop working and you have to
upgrade or replace them. But the HD24 will still keep on
running, MIDI Machine Control will ALWAYS work regardless of OS
version. There's a REASON why I keep a lot of hardware in my
studio.
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