Hill Audio are a long-established, British company whose product lines, thus far, have primarily catered for road and PA users. Their latest design, the Multimix, hopes to further expand their well-earned reputation for good quality, 'transparent' mixers into the realm of recording and audiovisual production.
Usually one can describe a mixer by its input/output format eg. 16 input, 4 output. It is not as simple as that with Hill's Multimix, however, as the unit is capable of several formats, such as 16-4, 16-2, 12-4 etc., which is a fair enough reason to christen your product the 'Multimix', I suppose.
The unit has been designed to fit a standard 19" wide equipment rack and occupies 14" (8U) of rack space. With such compact dimensions one would expect the mixer front panel to be extremely cramped, especially since there are sixteen input channels. The location of all connections (apart from headphones) on the rear panel, and the utilisation of smaller control knobs than standard, however, successfully combine to make the device an extremely comfortable mixer to use.
The decision to make the mixer rack-mountable means that it must be placed in an angled rack to obtain optimum performance, as it's extremely difficult to utilise the faders correctly when fixed in an upright position. Neither can it be used free-standing without the optional extra wooden end cheeks as the rear panel connections contrive to prevent this.
Visually, the Multimix is quite eye-catching: colour-coded knobs and yellow legending providing instant recognition of all function controls. The pressed steel construction is covered in a durable black finish created by a process known as 'powder coating', and large handles mounted on the outer front panel edges assist when carrying the device.
The front panel is divided into 16 input channels with a master output section contained within the space of a further input channel to the far right. All channels, except numbers 13 to 16, have identical controls and layout. The latter four channels can be utilised as subgroups if the mixer is being used for multitrack recording, and have red faders as opposed to white for inputs, but with none of the group routing buttons found on all other channels.
The rundown of channel controls is as follows: the input gain, with a mic (up)/line (down) selector button and -26dB attenuator pad button are used to accommodate mic or line inputs. The electronically balanced mic inputs have an impedance of 1-2 kilohms, which matched the AKG D202 mic used for test recordings with no ill effect. The high impedance line inputs were used for direct connection of a Roland TR808 drum machine and Yamaha DX7 synth, but lacked enough input gain, even with the levels turned to full on, to give a good reading on the master output LED ladders situated on the far right of the mixer.
Three band input equalisation is offered on the Multimix, with the chosen centre frequencies at 10kHz, 1kHz and 100Hz. In use, these provided only a minimal amount of tonal correction, which means you really do have to get your sounds right at source. I personally would have liked to have seen a more flexible swept mid control in place of the 1kHz function, or alternatively a few extra bands of fixed frequency EQ. It's not as if you can take a direct output from an input channel to a graphic equaliser either, if you really need to iron out some troublesome frequency, as none are provided!
A phantom power on/off button is next in line, and its good to see this facility included. Unfortunately, the internal supply provides only +15 volts rather than the more common +48V. The reason for this lies in cost, I suspect. Most types of capacitor mics will operate quite happily on a +15V supply, but they will suffer a corresponding loss in dynamic range, so be prepared.
Two auxiliary send level controls are provided on the Multimix - one pre and one postfader. 'Pre' is usually used to set up a foldback mix (mono) which can be heard even when the faders are closed, whilst the postfade auxiliary is best used as an effects send to an external unit patched into the rear panel send/return loop.
Only having two auxiliaries is a distinct limitation for today's recording needs, but if you find yourself not requiring the foldback auxiliary, it can be re-wired internally to provide a second post-fade effects send if you so desire.
Next is the input pan control which works in conjunction with the three routing buttons (1/2, 3/4 and Master) in the usual manner.
The final controls are the PFL on/off and Mute buttons. Mute seems a bit of a luxury to me, but effectively mutes the output signal of the selected channel. It can, for example, be used to remove any background noise/hiss that may be generated by unused input channels. PFL on the other hand mutes all channels except the one chosen, allowing it to be heard (in mono) via headphones which are (inconveniently) plugged into the top right jack socket, and whose overall volume level is controlled by the rotary pot below.
Rather surprisingly, the PFL bus is the only means provided of monitoring, audibly, the input signals. It's impossible to obtain a true monitor mix via headphones; you need to have all the PFL buttons depressed to do so and even then what you hear is only in mono.
There are also no dedicated monitor connections on the rear panel, so you'll need to use a twin feed from the main left/right jack outputs to your power amp and monitor speakers, which is a tedious hassle! It also means that you always have to route your signals to the master outputs, as well as to the groups, in order for them to be heard over your monitors when multitracking.
The final channel feature is a 90 mm long carbon track fader, which had a slightly uneven action to it on some channels of the review model, but was quiet and noise free in operation. The master left and right faders have been closely placed on the Multimix to allow one finger operation, which is a philosophy I'd like to see extended to more mixers, as it makes smooth level changes easier whilst freeing your other hand to do other things.
The ability to fit sixteen channels comfortably in a 19" wide space has been achieved partly by the exclusion of group and master VU meters. To compensate for their omission, Hill offer a compromise in the form of 'peak' LEDs on all input channels, as well as a second LED on the four subgroups and two 12 step 'traffic light' LED ladders for the master stereo outputs.
The mixer's operating level is set so that a 0dB meter reading produces an output voltage of +4dBu. The input peak LEDs are set to light when they reach a level of +4dBu which would correspond to the 0dB reading on a VU meter, and it's best to set your input gain control so that the LED is flickering on and off most of the time. There's still some 15dB of signal headroom available when the LED lights which nicely takes care of any heavy transients.
On channels 13-16 (the subgroups) a postfade LED is also provided. This operates exactly the same way as for the input peak LED, except that it indicates the level of the signal at the group output, which is controlled by the position of the group fader.
With care, the setting of input and output levels is soon mastered using the peak LED system, but it is a compromise. You only ever know that your signals are either below or above the +4dBu level; you don't know by how much, however, and you have to resort to audible feedback from your ears and blatant trial and error to discover whether it's the input which is being overloaded, or the group, for example.
The post-fade auxiliary bus has no master send level, only an overall return level controlling the balance of the effected signal in the stereo output mix. A pan control located in the master section also lets you position the return effect across the stereo image.
Below this control is a rotary pot labelled 'Mono'. This gives a pre-determined mono mix of the stereo outputs accessed via a rear panel jack socket. Since the signal is tapped off before the main stereo faders, it can be used as a 'cue' facility in theatrical works, say, or even as a master output to a mono tape recorder for audio-visual soundtracks etc.
As on the input channels, Mute and PFL buttons are included in the master section, but depression of PFL routes the master output signals to the headphone socket where they can be monitored in stereo as opposed to the usual mono for the inputs.
As previously stated, all interfacing of equipment takes place via the rear panel-mounted connections. All sixteen channels feature a 3 pin XLR balanced mic input and a ¼" jack line input (unbalanced). Pin 3 is used as the positive (hot) terminal, for readers' reference, but unfortunately these XLR connectors have been riveted in place which renders servicing/replacement an unnecessarily difficult job!
Input channels 1-4 have an additional jack input which is designed to permit direct connection of turntables for playback/mixing of records. This will obviously appeal to A-V users, theatre and drama productions also, where background music/sound effects are often required. The normal line input is disconnected if this input is used and full RIAA equalisation is provided to match the output signal characteristics of the turntables. I would have thought that these RIAA inputs would have used phono connectors in place of jacks though, as most turntables terminate in phono plugs. It might have saved time on a re-wiring job...
Other connections are all via mono jacks and include the two auxiliary sends and effects return, mono (summed) output, and the left/right outputs.
If used for multitracking in its 12-4-2 or 16-4-2 formats, the four subgroups (channels 13-16) will probably be used to feed four separate tracks of a multitrack recorder, and so a 'direct output' is included on each of these channels for connection to the relevant input channel of the recorder. The recorded, 'off-tape' signals must, however, be patched into four of the input channels if playback is to be achieved, and routed in stereo if overdubbing is required.
If recording a drum kit, say, with several microphones, these can be fed to individual input channels and then all routed to one subgroup. The chosen subgroup fader can then be used to control the overall volume of the drum mics in one easy movement without recourse to adjusting the individual mic input faders.
This facility is possible on the Multimix using the last four input channel faders. However, the same channels can also be used simultaneously for extra input signals, with full EQ and effects send capability. This makes possible 16 into 2 mixing with up to four subgroups, which is a highly desirable function for PA work.
It must be pointed out, though, that when multitracking, the EQ on the last four channels is not affecting the output group signals, only the channel inputs (if in use).
Circuit-wise, the Hill Multimix makes extensive use of socketed 5532 op amps, which are good quality, low-noise types. They undoubtedly account for the generally low background system noise which is specified at a level of -126dB - above par for the budget mixer course.
Testing the Multimix proved a bit of a nightmare however, as it had to be mounted in a vertical 19" rack. This meant that I had to keep on reaching behind the rack to unplug leads. I suspect that full-time owners of this unit will make use of a patchbay, and hardwire all connections to this. It's the most logical solution really.
Generally, I found multitrack recording with this unit to be an extremely inconvenient task, especially when attempting simultaneous overdubbing. I really missed not having any form of continuous level metering on the groups and had to constantly check levels on the multitrack recorder itself.
The necessity to rack-mount the mixer, for the purpose of the review, in an upright rack, prevented me from undertaking any serious use of the faders, but I'm sure this would not be a problem when the mixer is positioned at a suitable angle ie. less than 45 degrees.
I initially approached the Multimix as a recording mixer intended for multitrack work. It soon became blatantly obvious however, that it is less than ideally suited to such use. It appears to be a glorified PA mixer with several amendments to make it suitable for video post-production work or even outside broadcast applications for those on a limited budget, such as schools and colleges.
Even when viewed as such, I still can't help thinking that there are much better buys around for the asking price of almost £1000!
The Hill Multimix is expensive for what you get in terms of facilities, but quality-wise, it is a very good unit. If it was considerably less expensive and didn't have such an air of compromise about it, then perhaps it would prove a worthwhile purchase. However, if you're looking for a good value, quality mixer to help you record, then you'd do better to consider one of the other mixers already reviewed in HSR. Recording in my view should be fun - with the Hill Multimix it isn't!
The Multimix retails at £977.50 including VAT.
If you'd like more information, contact: Hill Audio Ltd. (Contact Details).
Review by Ian Gilby
Previous article in this issue:
Next article in this issue:
mu:zines is the result of thousands of hours of effort, and will require many thousands more going forward to reach our goals of getting all this content online.
If you value this resource, you can support this project - it really helps!