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Korg PXR4

Digital Recording Studio By Paul White
Published December 2001

The PXR4 — at its actual size!The PXR4 — at its actual size!

Korg's new pocket‑sized multitracker gives you everything you need to record impressive demos on the road, and also lets you transfer the tracks to a computer via USB for backup and archiving.

Korg's PXR4 is one of the latest generation of compact, entry‑level four‑track recorders which use SmartMedia cards instead of tape or hard disk. In some respects it can be considered as a 21st‑century alternative to the analogue cassette multitracker, but, in common with most digital workstations, it includes a number of digital effects as well as a recorder and mixer. Furthermore, each of the four tracks has eight virtual tracks for storing alternate takes. Before you get too carried away, though, the use of SmartMedia places restrictions on the available recording time.

As supplied, the Korg PXR4 comes with a 16Mb SmartMedia card, which if it were to be used to record uncompressed 16‑bit audio at a sample rate of 44.1kHz would yield a four‑track recording time of roughly 45 seconds. Clearly that is impractically short, so, to make the best use of the media, 16‑bit MPEG1 Layer 2 compression is used (albeit via 24‑bit converters) at a sample rate of 32kHz, which means the upper frequency limit is around 15 to 16kHz.

Three quality modes are available, each of which trades recording time against recording quality. With the supplied 16Mb card, the highest‑quality mode provides approximately 11 track‑minutes or just over two and a half minutes of four‑track recording with all four tracks used (but not the virtual tracks). A Standard mode increases the recording time to 16 track‑minutes, while Economy mode takes this up to 33 track‑minutes, but, for any serious work, I'd suggest using only the best‑quality mode. Realistically, the memory provided will hold only one short song or a couple of jingles, but you can use any SmartMedia card of between 4Mb and 128Mb capacity, the latter of which should leave you with around 20 minutes of four‑track recording time to play with. The card slot is located on the side of the case beneath a protective cover. Given that it's possible to mix within the Korg PXR4 to produce a final, stereo audio file, I'd suggest 64Mb of memory as being a realistic minimum, especially if you intend to take advantage of the virtual tracks.

With a cassette multitracker, you simply put in a new cassette when the old one is full, but SmartMedia is far too expensive to treat as a tape substitute. Instead, you either wipe the memory whenever you finish a song, with no hope of going back and remixing, or you back up the data somehow. Fortunately, Korg have built a USB port into the PXR4 so you don't even have to buy a SmartMedia reader to back up the recorded data to your computer — all you need is a standard USB cable (not provided). If you don't have a PC or Mac computer with USB (the Korg PXR4 works with both platforms), you can fit a USB card to an older computer for under £30 in the UK, or you can use a regular SmartMedia reader that costs about the same. If you don't have a computer at all, then it may be wiser to consider an alternative recording system.

Studio Tour

The PXR4 records to a removable SmartMedia memory card.The PXR4 records to a removable SmartMedia memory card.

As virtual studios go, this has to be amongst the most compact yet devised. Measuring just 124 x 110 x 34mm, the unit weighs in at 265g and can be powered either from two AA cells or from the included AC adaptor. A soft protective carry pouch is also included, and the whole thing looks not unlike a small transistor radio.

Though I could give a blow‑by‑blow account of all the buttons and where they live, there are so few that they can all be seen clearly in the photograph, and any functions that don't have an obvious location are usually to be found in the System menu.

The power switch on the back of the machine has two on positions, one of which switches on the LCD backlight at the expense of a shorter battery life; as with all such machines, the LCD handles everything from patch names and parameter values to metering and routing status. There's an internal mic for recording, or you can choose a mono instrument jack or a stereo mini jack as alternatives. Using the mini jack, stereo signals can be recorded to track pairs 1/2 or 3/4. A slide switch selects between Mic, Line and Guitar input while a small switch underneath the unit can be used to choose from two possible guitar sensitivities. Physical rotary controls are located on the front edge of the machine for phones volume and input gain trim.

What looks like a volume control at the upper right of the front panel is actually a rotary encoder for parameter adjustment, and the tiny cursor pad next to it rocks in four directions to provide conventional cursor control. The right‑hand cursor doubles as a context‑sensitive 'Enter' button, while a dedicated Exit button gets you out of the current menu. Because there are so few buttons, virtually all are dual function, with a Shift button accessing the alternate function, while the transport is handled by a miniature set of fairly conventional transport controls at the bottom right of the panel. You can fast wind in either direction from play mode and listen to the audio garble its way past at double speed (by holding down the fast wind buttons), and there's also a Store Mark button for creating markers (either in play or stop mode) — up to 100 marker points can be added per Song. Most editing functions refer to marker locations rather than absolute time. Holding down Play while in play mode slows the playback down to half speed.

Each of the four tracks has its own level fader, with a button above it that acts as a record‑ready/play mode selector. The level faders may also be used for direct effect parameter adjustment. A separate fader sets the level of the final mix and the Mixer button above it allows you to access the hidden channel‑control functions for any selected track. Here you can set the pan position, aux send level (separately adjustable for left and right effects input) and the channel level, but there is no EQ built into the mixer. Nevertheless, there is a comprehensive effects system that provides 77 different types of effect, including EQ, that can be deployed in four different ways. These effects are arranged as 100 presets and 100 user patches, where some of the effects combinations combine up to five chained effects blocks.

The first effects category is Guitar and is designed to allow effects to be added to a mono source such that the effects are recorded to the track. These include guitar amp modelling with overdrive, chorus and other common guitar production effects derived from the Korg Pandora effects processor. The effects menu is accessed via the Effect/Tuner button which toggles between the effects section and an in‑built guitar tuner.

Insert effects can be used with mono or stereo line‑level sources, again recording the effects to the track, while the Master effect uses the Send Left and Send Right controls to share an effect (such as reverb) between all four tracks being mixed. Lastly comes Final, where you might, for example, use a dynamic effect such as a limiter or an EQ setting to treat the final stereo mix while recording it to an external stereo machine or while bouncing it to a new Song internally. Note, however, that only one effect configuration can be used at a time, so if you want to add reverb while you mix and you also want to add some kind of mastering processing, you'll first have to produce a mix using the reverb (via the channel sends), then treat the resulting mix again via the mastering effects. A number of simple mastering presets are included to get you started and it's also possible to switch on a Sub mode in the System memory that allows a live input to be added to a mix.

Effects can be edited by first selecting one of eight possible chained configurations and then adjusting the parameters within each effect block. The types of chains available depend on whether you select a Guitar, Insert, Master or Final effect and relatively few parameters are editable, which makes programming effects fairly straightforward.


Korg PXR4

The first step after installing a memory card is to format it via the System menu, after which you set up a new Song (which you can name if you don't like the title New Song), at the same time specifying the recording quality.

Once the basic setup is complete, all you need do is select a recording source, arm a track for recording, adjust the record gain for a sensible meter reading and then get on with recording. The playback level is set using the faders, and putting the machine into record involves first hitting Record, then Play. When you want to punch in, you hit Record while the machine is playing, with the desired track armed. An auto monitor mode can be enabled to handle the monitor switching from track to source. If Auto isn't active, an armed track always monitors its input and an unarmed track always plays back the recorded contents of that track.

Switching on Rhythm brings up a metronome adjustable from 40 to 240bpm. If you don't want a plain beep, there are 55 rhythms from which to choose. The song position counter can show plain time, or bars and beats, the latter being better if you're playing along to the rhythm track and need to edit. The general quality of the rhythms is pretty good, and they would be easily usable as a drum machine for demo purposes. Although your rhythm will play back with the Song, I could find no way to record it as part of a mixed track other than via the analogue outs.

Track editing is no more cumbersome than with any other recorder of this type, and provides for the usual copying, inserting and deleting options, along with time compression or expansion. This all takes place from the System menu (as does selecting virtual tracks) and copying a part involves selecting a source track along with start and end times (defined by markers), a destination track and the time at which you want the copied section to start. You can also specify the number of copies you want to make. After that you hit the right cursor button for OK and then run for the Undo button if it didn't work out.

Because the Korg PXR4 is so small, and because of the limited number of buttons, performing some of the operations can be a little tedious because of the necessity to navigate menus, but, once you've used the machine for a short while, you soon get used to finding what you want pretty quickly. The most commonly used functions tend to be easiest to get to and the basic process of recording and overdubbing is friendly enough.

Tracks can be bounced conventionally, via a list of preset track bounce options, or all four tracks may be bounced to a new stereo mix — this mix is created as a whole new Song. My only complaint is that some of the menu legending on the LCD is very small, so if you wear reading glasses, you'll need to keep them close at hand when driving this little machine.

Getting Your Backup

Korg PXR4

Once you've done some recording, it's a fairly simple matter to back up your work to your computer's hard drive via the integral USB connection, but it is necessary to use the mains adaptor when doing this. The USB connection mode is located in the System menu (where else?) and, after you have activated it, the PXR4 memory appears on your computer's desktop as a mounted external drive. When opened, this reveals each Song, along with its audio files, stored in a separate folder. These folders (which must be copied complete) can be dragged to your hard drive, and when you want to restore a Song to continue work on it, you can drag it from the hard drive back into the PXR4 window, providing there is sufficient free memory. Because the PXR4 appears and acts as a mounted drive, you can also delete Songs by dragging them to the 'trash can' on your computer desktop.

Stereo Songs created by bouncing to a new Song are stereo‑format MP2 files and so can be auditioned via a suitable player. This makes the PXR4 a convenient tool for creating music to be distributed via the Internet, though having said that, no program on my Mac, including Quicktime Movie Player, would open the PXR4's files.

Feel The Quality

Korg PXR4

I know that some people are very resistant to the idea of data compression, even in its most benign form, but I have to admit to being pleasantly surprised by the MPEG1 Layer 2 system used by the PXR4 in high‑quality mode, which is subjectively little different to Minidisc. The lower‑quality modes are OK when all you need is an ideas scratch pad. Some low‑level resolution is undoubtedly lost due to the compression used, but for pop music, which has a relatively restricted dynamic range, the high‑quality mode sounds quite clean and transparent, even when working with good‑quality headphones. I certainly prefer the sound to analogue cassette and, with typical pop music, I think you might be surprised how many people wouldn't be able to distinguish it from uncompressed audio. Be in no doubt that you can produce very polished demos using this recorder.

What is even more surprising is the quality of the in‑built microphone and, because there are no moving parts, background noise is limited to electronic noise and handling noise. For best results, I'd be inclined stand the recorder on some suitable perch, rather than trying to hold it, as it's easy to generate handling noise. During my tests, I found the electronic background noise to be reasonably low and the subjective quality of miked vocals was significantly more natural‑sounding than a budget electret capsule had any right to be.

The guitar effects come straight from Pandora, as far as I can see, and my impression is that they're actually very good at producing clean or overdrive sounds, but less good at raunch and blues. There are some nice chorus and delay effects, as well as compression, so you can get a very 'produced' guitar sound very easily. If you need to add reverb, you'll find that the included reverb effects work well enough when used at sensible levels, and though they're aren't of the Lexicon/TC calibre, they certainly won't disgrace your recordings.

The same is true of the time‑expansion facility, which can be used to copy a section from one track and then stretch or compress it to make it fit a different length at its destination, with or without a corresponding pitch‑change. If you try to slow something to half speed, then time‑stretch artefacts are clearly audible, but to a lesser extent than with most real‑time pitch‑shifters. At sensible settings, the results are much more natural.


I can confirm that all the basic features of the PXR4 work extremely well, despite some operations being a bit long‑winded. The sound quality is far better than I expected, the effects are more than reasonable, and the ability to back up onto a Mac or PC via USB is most welcome. However, budget for a bigger memory card if you aim to make any sensible use of this machine, especially if you want to bounce your stereo master onto the memory card along with your Song tracks.

Having the ability to power the machine via batteries is clearly good news for location work, as is the availability of in‑built guitar effects and the integral microphone, though you need to take along the mains PSU for those occasions when you want to back up to your laptop. I ran the machine all day on a pair of nickel metal hydride rechargeables and it was still going strong by tea time, so the battery life seems to be reasonable. Though I don't think I'd go as far as to suggest you would want to make master recordings on a machine of this nature, you might just get away with it if you were careful with your recording, and it is certainly ideal as a songwriting tool, for putting together decent‑quality demos, or for creating music to put on the Internet. The lower‑quality recording modes stretch the available time somewhat, but are best avoided for any serious work. If you feel the need to own a complete digital recording studio that you could easily lose down the back of a sofa, then don't miss trying this out.


  • Compact, yet provides everything you need to record and mix.
  • Credible effects and good basic editing facilities.
  • USB connector for Mac and PC backup.


  • The compact format means that some functions are quite a few cursor clicks away and some of the LCD information is very small.
  • Storage capacity of supplied memory card too small for any serious use.


An ideal travel companion for the musician who fancies the idea of a complete digital recording studio that will fit into a bum bag!