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TC Electronic Konnekt 24D

Firewire Audio & MIDI Interface For Mac & PC
By John Walden

TC Electronic Konnekt 24D

TC Electronic are well respected for their range of effects processors, so what might the company's first audio/MIDI interface, the Konnekt 24D, offer to make it stand out amongst the Firewire crowd?

Another month, another compact Firewire-based audio/MIDI interface! The Konnekt 24D represents TC Electronic's first foray into this particular market and, even with TC's excellent reputation, the 24D is likely to require something special if it is to make a significant impression against the established competition from Echo, MOTU, M-Audio, PreSonus, Focusrite, Digidesign, Edirol and RME (apologies if I've missed anyone out — but you get the point!).

In essence, the Konnekt 24D offers a four-in/four-out analogue format, with two of the inputs featuring well specified mic preamps and phantom power, 24-bit audio and sampling rates up to 192kHz. Digital I/O and MIDI I/O are also provided, all housed in a smart and compact desktop box. However, the Konnekt 24D's trick (and it is perhaps no surprise to those familiar with TC's Powercore system) is the inclusion of some DSP effects processing. The two key elements of this are the Fabrik C channel strip and the Fabrik R reverb. Versions of both these plug-ins are available for the Powercore system, but their combined list price for that format is not dissimilar to that of the Konnekt 24D itself.

The inclusion of DSP processing makes the 24D an intriguing proposition. So how does this combination of audio/MIDI interface and DSP effects work in practice?

Let's Get Konnekted

The Konnekt 24D is both compact and sturdy enough to be used on the move — with suitable care and attention, I'd have no qualms about using it outside a studio environment. The front panel features two balanced Neutrik 'Combi' XLR jacks with individual gain controls and a global switch to engage phantom power. Both also feature a 20dB pad switch and a three-stage input-level LED. As with similar units, this metering lacks a little subtlety but is better than having to rely solely on software meters. A switch is also provided for toggling channels one and two between the front-panel inputs and the rear-panel line input jacks. The 'monitor' section contains two large knobs labelled Source level and Output level respectively. As described below, the former can be configured to control a number of different aspects of the 24D's features. The inclusion of a dedicated output volume control is most welcome, as it quickly becomes irritating to rely on a mouse for adjusting overall playback volume. Finally, two headphone outputs are included, one of which automatically mutes the main output.

The simple Near Control Panel Mixer page.The simple Near Control Panel Mixer page.

The power button is positioned on the rear panel — fine for desktop use, but not so convenient if you wanted to rack the 24D. The rear panel also houses a pair of Firewire connectors (multiple Konnekts can be linked), MIDI I/O, and digital I/O in both coaxial and optical formats. The latter support both S/PDIF and ADAT. Connectivity is completed by the four-in/four-out balanced quarter-inch line-level jacks. Used with a six-pin Firewire port the 24D is bus powered, but a power supply is included for use with a four-pin port (more common on laptops) or when the unit is used in stand-alone mode without a computer.

The TC Near Control Panel application is included and provides access to all the additional functions of the unit. As well as the Fabrik C and Fabrik R effects, the 24D bundle includes a copy of Cubase LE, the Konnekt Tuner (useful for guitar players) and a special 'Konnekt' version of TC's Assimilator plug-in. This EQ-matching plug-in for Powercore was reviewed by Paul White in the April 2003 issue of SOS. As far as I can tell, the bundled version here is functionally identical but uses the host computer's CPU and is only available when the 24D is connected to the system. Finally, an excellent PDF manual (how often do the words 'excellent' and 'manual' appear in the same sentence when referring to hi-tech equipment?) is provided on the installation CD. The manual covers both the 24D and its junior sibling, the Konnekt 8 (see the 'Small Konnektions' box).

Firewire Chip Set Compatibility

My initial attempts to get the Konnekt 24D working with my main test PC were somewhat frustrating and I couldn't get the TC Near Control Panel to recognise that the unit was present. I tried the unit on a further desktop computer and a laptop (each with different Firewire interfaces) and experienced similar difficulties — either no connection or stuttering audio. Thinking I had simply been sent a faulty unit, TC Electronic kindly sent me a second 24D but I had exactly the same problems with this. I finally overcame the issue by installing a new Firewire interface (a Belkin PCI card) into my main test system, at which point both 24Ds worked first time of asking. Coincidentally, at the end of this process I happened to take delivery of a new PC laptop and the 24D also worked flawlessly with that. TC Electronic's Thomas Valter confirmed that there are a small number of Firewire chip sets that can be problematic with the 24D and that these are the same as for the Powercore system. Potential purchasers might want to test the 24D with their own hardware prior to purchase but, with PCI Firewire cards being relatively inexpensive, the issue can be easily solved. And, as detailed towards the end of the main text, given the subsequent performance of the interface, I found that overcoming these initial teething problems was well worth the effort.

Testing, 1, 2, 3

I initially experienced some difficulties getting the Konnekt 24D to function correctly (see the 'Firewire Chip Set Compatibility' box for a brief summary) but once these had been overcome the unit performed flawlessly. Testing the analogue I/O via Rightmark's Audio Analyser v5.5 produced very respectable results. These obviously varied slightly with bit depth, sample rate and which inputs were used but, for example, using the line-level I/O at 24-bit, 44.1kHz, I was able to get within a few dB of the manufacturer's stated 111dB(A) signal-to-noise ratio and the total harmonic distortion of 0.002 percent. While I'm sure there are more esoteric (and expensive) audio interfaces out there that would produce better absolute figures, the 24D is more than up to the task for most mobile, home or project studio applications.

The impression from my own subjective playback and recording tests was overwhelmingly positive. Both the line and headphone outputs reproduced a range of commercial material very well. The stereo imaging was good and mixes sounded clear and detailed. There was also plenty of level on the headphone outputs. Recordings made via the line inputs were clean, while the mic-preamps produced excellent results and, via the pad and gain controls, are capable of dealing with a very wide range of input signal levels.

TC Near

TC's 'MINT' technology includes intriguing triangular graphs for setting certain parameters, as shown here for the Compressor control in Fabrik C.TC's 'MINT' technology includes intriguing triangular graphs for setting certain parameters, as shown here for the Compressor control in Fabrik C.Detailed control of the 24D is achieved through the TC Near Control Panel. This is arranged in a number of tabbed screens, including the System Settings screen, which allows the buffer size to be set and also provides a very useful 'Check For Updates' function if the host computer is connected to the Internet. This will update both software and the 24D's firmware as required.

The well designed Mixer page allows all the input sources to be balanced and also includes a fader for the DAW output and overall output. Each channel features a send control, enabling some ambience to be applied via the Fabrik R processor, while an instance of Fabrik C is available for channels one and two. The channel one and two inputs are auto-sensing and the graphics change depending upon the type of jack inserted — a nice touch. Mixer settings can be saved via the File button (located at bottom right) and three presets can be loaded and instantly recalled via the P1-P3 buttons, duplicating the function of the DSP total recall buttons on the 24D's front panel. The Setup page provides some additional system-type settings and also allows the input pairs to be linked or unlinked for stereo or mono operation. This page is also where the front-panel Source level control is configured.

The Setup page includes options for configuring the Source level control.The Setup page includes options for configuring the Source level control.Fabrik C provides a combination of processing suitable for a voice channel. This includes four-band EQ, compressor (either full-band or three-band), de-esser and limiter. The user interfaces for both Fabrik C and Fabrik R use what TC refer to as Meta Intuitive Navigation Technology (MINT — there really should be an annual prize for contrived acronyms), which tries to provide a friendly front-end for the user. While the EQ control set follows a familiar format and both the de-esser and limiter offer a single control each, the compressor is controlled in a rather novel fashion. Four circular icons — labelled 'S', 'G', 'C' and 'L' — are positioned on screen to set the compression controls (see screenshot, above right). The 'S' icon is used to specify the type of audio source from a grid of options (with choices including vocals, solo instruments and different types of mixes). Selecting the 'G', 'C' or 'L' icons changes the display to a triangular graph, the corners of which represent the high, mid and low bands of the compressor. As an example, dragging the 'L' icon to the top of the triangle sets a high level for the mid-band compressor and reduces the level on the low and high bands. The 'G' (gain) and 'C' (compression) controls operate in the same way. MINT or not, this does take a little getting used to, but fortunately there is a decent enough collection of presets for Fabrik C to get you started. What is clear, however, is that the sound of the processor is very musical.

Fabrik R also features MINT and is based around four of TC's reverb algorithms: hall, plate, club and live. Four icons — 'R' (reverb), 'C' (colour), 'M' (modulation) and 'D' (distance) — allow the user to tweak the nature of the reverb further. As an example, the 'R' icon changes the reverb pre-delay and decay times, while the 'D' icon changes the balance between the dry, early reflections and main reverb signals. Again, this does take a little getting used to but the supplied presets help. While I don't imagine the 24D contains anywhere near the same amount of processing power as some of TC's high-end processors, there are some very useable reverbs here. Given the price of the 24D, the inclusion of such a respectable reverb processor is quite a big plus.

Small Konnektions

The Konnekt 8 is a more streamlined, lower-cost (£245) alternative to the 24D, featuring two-in/two-out analogue interfacing with the same mic preamps as the 24D. A pair of Aux inputs allows other signals to be monitored through the Konnekt 8, but these signals cannot be recorded. Only the coaxial S/PDIF digital I/O is present (though this can be used with the analogue I/O to give simultaneous four-in/four-out operation) and it does not feature the DSP processing of its bigger brother, although Cubase LE is still part of the bundle. At the price it offers excellent audio quality, but I think the extra outlay for the Konnekt 24D is well worth making.

In Use

While the features and sound quality of the 24D are undoubtedly impressive in their own right, the advantages of the design are really hammered home when the unit is hooked up to your DAW. When tracking in Cubase 4, the convenience of having both a channel strip and reverb available without having to patch in additional hardware or resort to software monitoring through Cubase makes the whole recording process considerably easier. When tracking, Fabrik R serves as an excellent monitoring reverb — you can give the performer some ambience in their headphones but record the dry signal.

Konnekt 24D offers a four-in/four-out analogue format, with two of the inputs featuring well specified mic preamps and phantom power, 24-bit audio and sampling rates up to 192kHz. Digital I/O and MIDI I/O are also provided, all housed in a smart and compact desktop box.Konnekt 24D offers a four-in/four-out analogue format, with two of the inputs featuring well specified mic preamps and phantom power, 24-bit audio and sampling rates up to 192kHz. Digital I/O and MIDI I/O are also provided, all housed in a smart and compact desktop box.The same is also true of Fabrik C — when engaged, its processing is monitored but doesn't have to be recorded. However, the 24D actually features a number of virtual output pairs that are fed via Firewire to the host DAW. As shown in the screen shot below, in Cubase, channels one and two provide an unprocessed signal while, for example, channels five and six provide a signal processed by Fabrik C but not Fabrik R. By selecting which input pair feeds your audio track you can chose which signal to record — dry or processed. For microphone-sourced recordings, I found this flexible and extremely convenient. While we would all like to be getting our vocal and acoustic instrument sounds exactly right at source rather than applying processing, it's not always possible in a non-ideal acoustic space. In such circumstances, the DSP effects of the 24D make it so easy to add a little corrective EQ or compression. I found this particularly useful to brighten up recordings of my acoustic guitar, an instrument I always have trouble with in my own studio. The 24D made this task a breeze.

The 24D sends a number of virtual audio channels to the host computer via the Firewire connection. For example, taking your audio input from the first stereo pair allows you to monitor through Fabrik C while recording dry. In contrast, the third stereo pair records the signal including any Fabrik C processing.The 24D sends a number of virtual audio channels to the host computer via the Firewire connection. For example, taking your audio input from the first stereo pair allows you to monitor through Fabrik C while recording dry. In contrast, the third stereo pair records the signal including any Fabrik C processing.A recent firmware update for the 24D means that the effects are not, however, limited to the tracking phase of a project. The Fabrik C and Fabrik R pages in TC Near feature a routing option switching the effects to 'plug-in mode'. This provides a single instance of each effect in your DAW. Most obviously, Fabrik C might be used as an insert on an individual audio track, while Fabrik R could be placed in an effects channel and used as a send and return reverb. This worked a treat, and having access to Fabrik R while mixing, without CPU overhead, is a real plus.

My only other comment would be that the drivers seem very solid. I was able to work with a comfortable buffer of 256 samples in some quite complex Cubase 4 projects, giving both low latency and reliable performance. Testing within other audio applications — Sound Forge, Acid Pro and Wavelab — produced equally good results. TC confirmed that drivers for Windows Vista are in the early stages of testing. At the time of writing, no release date has been confirmed.

Conclusions

The Konnekt 24D is an intriguing and novel take on the compact audio/MIDI interface. At this price point, I have no complaints about the audio quality: it sounds very good and will be more than a match for the acoustics of most mobile, home and project studio environments.

The close integration of the DSP effects is, as far as I'm aware, unique, and in one simple step TC have removed the need to patch in external hardware during tracking. This integration is such a neat idea that I assume other manufacturers will follow suit — but until then the Konnekt 24D offers a very novel twist that, for me, adds a really competitive edge. Given the complete package on offer, it is difficult not to see the 24D as excellent value for money. Indeed, so impressed was I by the combination of facilities offered by the Konnekt 24D that I bought the review unit. Highly recommended. 

Pros

  • Very good audio quality.
  • Integrated DSP effects are excellent.
  • Provides all the essential processors required for tracking in a single box.
  • Hardware and software bundle represents excellent value for money.

Cons

  • Worth checking Firewire compatibility before purchasing.
  • Rear-panel power switch a bit irritating.

Summary

The basic idea behind TC Electronic's Konnekt 24D is simple — combining an audio/MIDI interface with a DSP-based voice channel and reverb — but it instantly integrates the key requirements of the tracking stage of the recording process into a single device. The simple ideas are often the best and I can only imagine that other manufacturers will consider following TC's lead.

information

£339 including VAT.

TC Electronic UK +44 (0)800 917 8926.

+44 (0)800 917 6510.

infouk@tcelectronic.com

www.tcelectronic.com

Published May 2007