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Studiomaster P7 In-Line Mixer

There's no shortage of in-line, low cost desks on the market — an odd time, you might think, for Studiomaster to launch their first in-line mixer. The P7, however, offers very worthy competition to the more established models, as Ian Gilby discovers.

Designed for the home recording and project studio market, the P7 is an in line 16:8:2 mixing console with MIDI muting. Rather than offering the user the option of different frame sizes, it is instead expandable in blocks of eight channels up to a maximum of 40 which, at mixdown, provides no fewer than 88 line level inputs. In addition to the eight routing busses, there are direct channel-to-tape switches so the P7 could be used with 16-track recorders or even 24-track if expander modules are fitted. The desk is unashamedly targeting the market currently served by the Soundcraft Spirit and Allen & Heath G3 and is not cosmetically dissimilar from either.

The great advantage of the in-line system format is that the monitor channels double as additional line inputs when you come to mix, effectively doubling the number of usable channel inputs. For those running sequencers with their multitracks, this is no minor consideration.

The P7 utilises a non-modular from of construction, the main worksurface being fabricated from a single sheet of steel. The input sockets are located towards the back of the top panel, which means you can get away without using a patchbay if you want to. Like its competitors, the console is grey with Studiomaster's own graphic styling retained around the controls. Plastic moulded end-cheeks complete the package and power comes from an external 2U PSU that can handle a fully expanded system. It also has no need for fan cooling which helps keep the noise at bay. A global phantom power switch sends 48V phantom power to the desk if required.


The channels all have line in plus tape in and out sockets on unbalanced jacks, an insert point on a stereo jack, and a balanced XLR mic input. 48V phantom power is switchable on each channel by means of recessed switches, which will help to prevent accidental operation, though if it is not required at all, it would be best to switch it off on the PSU. The master outputs are also presented on balanced XLRs, though these were omitted on the pre-production model sent for review.

The input swap switch is a familiar feature of in-line desks. While recording to the multitrack, the line inputs are routed through the input channels and out to tape via the Group faders. The outputs from the tape machine feed back into the monitor inputs so that the engineer can set up a rough working mix. Pressing the swap button routes the multitrack's outputs into the input channels and switches the line inputs to feed the monitor section. This would be the standard mixdown configuration.

The Mic/Line switch is accompanied by a 20dB pad which operates only on the mic input and the same gain control serves to control both mic and line levels. There are no dedicated Group output sockets on the P7 since each input channel has its own tape output. In other words, the Tape Out socket on channel 1 is actually the output for Group 1, and so on up to channel 8. This is repeated from channels 9 to 16 so that the second eight tracks of a 16-track tape machine can be addressed without need for repatching. Any channel can be isolated from the group routing by means of the Group/Direct switch which simply sends that channel signal back out of its own tape output and prevents that output being accessed via the routing switches on the other channels.

The 4-band EQ has sweep mids with 16dB cut on all bands. The high and low shelving control work at 12.5kHz and 60Hz respectively, while the two sweep mids cover 100Hz to 2kHz and 500Hz to 10kHz. Because there's dedicated EQ on the monitor you can assign the Hi and Lo controls to the monitor signal path. The sweep mids double as a full range equaliser for the input channel when the Hi and Lo controls are assigned to the Monitor path, again a common feature of pro inline desks. Though the controls are not detented, there is an EQ cut button.

Each strip has six auxiliary controls, three of which relate to the input channel and one to the monitor section. The other pair can be switched between the input and monitor signal paths as required. Aux 1-4 are post-fade while 5 and 6 are pre-fade. The latter are mixed together if no plug is inserted in the Aux 6 output socket, the idea being to allow a cue mix to be created using a mix of the input and monitor channels.

The monitor section is positioned between Aux 4 and Aux 5, and has both AFL and Mute/SIP buttons, the Mutes being connected to the MIDI muting system.

All the Mute buttons except those dedicated to the Aux sends operate either as a Mute or 'Solo In Place'. Pressing the button mutes the channel along with any auxiliaries assigned to that channel, and also send information to the MIDI mute computer which generates MIDI output note and velocity information.

That leaves the Pan pot, a row of routing buttons and the long-throw channel fader, all of which operate quite conventionally. Close by are the channel Mute/SIP and PFL buttons.


To the right of the desk is the master section which looks very much like that of a Soundcraft Spirit, except for the MIDI Muting control panel. There are eight Group faders, the stereo Master faders and the aux send and return controls, plus the usual talkback/oscillator section, stereo tape machine routing and the necessary monitor level pots.

There are four pairs of Group faders, each fader with its own PFL button, and a Group to L/R button serving each pair. This routes the Group to the stereo mix for subgrouping during mixing. All the Group outputs and the master stereo output have insert points and all the aux sends have their own master level controls. Aux 1 to 4 have Mute buttons connected to the MIDI mute system and aux sends 5 and 6 have AFL buttons.

The four aux returns are stereo, with 2-band EQ, level and Pan controls, as well as an Aux 6 control allowing the effect to be fed into the cue mix. All returns have full routing facilities.

Metering is by 16-step LED meters for the Group and Left/Right outputs and, as is quite common, the Right meter also shows the PFL level. The PFL (Pre Fade Listen) signal is quite independent of any fader setting, and is often used in the studio to optimise the channel input gain while recording.

An internal electret mic drives the talkback system, and may be routed to the Group or to Aux 6 outputs. The test oscillator provides 1 kHz and 10kHz tones, feeding the Group outputs. A recessed oscillator button prevents accidental operation.

Provision is made for the connection of two stereo tape machines — there's a nice touch in that there are routing buttons allowing the signal from either machine to be dubbed to the other. One set of 2-track connectors is on quarter-inch jacks, with the others on phono sockets. Either 2-track machine can be routed to the monitors.

There are two pairs of monitor outputs allowing the user to switch between alternative monitoring systems, the headphone output following the control room monitor signal.

The MIDI control panel is built around a 2-digit display window and a surprisingly small number of buttons. This also controls the Solo In Place mode and the novel PIN number security system. On powering up, the machine locks up with all the mutes switched on until a 4-digit security code is entered. After three wrong attempts, the machine will freeze up for two hours before you can try again. The facility can also be turned off, should you not want to be bothered by it every time you switch on.

MIDI muting is the simplest form of automation, and though many modern desks also offer level automation this costs rather more to implement.

The Studiomaster MIDI muting system uses 'soft' switching to avoid clicks when mutes are turned on or off and can be assigned to any of the 16 MIDI channels. Because there's also muting on the monitor channels, and four of the aux sends, the P7's automation extends to any secondary line inputs being fed in during the mix. There are two ways of implementing auto-muting systems; via an external sequencer using MIDI, or via an onboard system that allows the user to manually step through a hundred user-defined 'scenes'. A scene is a recording of all the mute positions on the desk at the instant when the scene was stored. A useful extra feature is the ability to store and recall four mute scenes directly from the four Mute Bus buttons — great if you only need one or two mute changes during a specific mix.

The user who has a sequencer with tape sync might opt to use the MIDI system, as this is completely automatic when programmed and is not restricted to a finite number of mute configurations or scenes. It is possible to call up a scene by means of a MIDI Program Change command, but recording the mute data directly to the sequencer offers far greater flexibility. Whenever a mute button is pressed, a MIDI Note On message is sent, followed an instant later by a Note Off. The mute on/off status is determined by the note velocity: 96 means mute on and 32 means mute off. When played back from the sequencer, the mixer will automatically mute and demute the channels exactly as recorded.

Many muting systems work on a similar principle, but they all have the failing that MIDI can't look into the past if you start the tape half way through a song — should the mutes be on or off? To get around this, mute data is also output as Controller dumps which are transmitted as regular bursts. These may be recorded to the sequencer, along with the note data, and are later read back by the mixer whenever the tape is started. The P7 scans for this data for a few seconds after the tape is started, and then goes back to using note information. The Controller data simply duplicates the note information when it is first recorded, but you edit note data on the sequencer, it could become outdated. In this case, new Controller information can be generated by filtering out the original Controller data on the sequencer and playing the mix data back through the mixer. The P7 then generates fresh Controller data and note information, which can be re-recorded on a spare sequencer track.

The Solo-In-Place facility is also to be found in the MIDI control section; pressing the master SIP button shifts between SIP or Mute operation. In SIP mode, depressing a Mute/SIP button silences all the other channels unless they are set to Solo Safe. Solo Safe enables effects and suchlike to remain active so that checking an instrument or voice will solo it with its effects and in its correct stereo position. SIP buttons should not be used during mixdown, as they affect the main stereo output and not just the control room monitor feed.


In its main areas of performance, the P7 behaves much like any other mid-priced console — it turns in a very reasonable noise performance, crosstalk between channels is reassuringly low, and there is plenty of flexibility. The Studiomaster EQ has a reputation for musicality which translates into smooth, predictable operation with no tendency to make things sounds harsh unless high levels of EQ are applied. The individually switchable phantom power on each channel is also a nice touch on such a low priced console. Ergonomically the console conforms pretty closely to the accepted in-line monitoring, split-group format that dominates the home and project studio mixer market. The only problem I would point to (one that is shared by others) is that the panel screening seems unnecessarily busy.

As pointed out, some of the controls that you'd expect to have centre detents don't have them, but as the EQ has a bypass function, I don't feel this is too serious. All the same, I don't know why they didn't put them in. There's also no way to discriminate the master control room level knob from the others and even the legending is a little confusing — I feel this particular control should always be made larger or different in some way, as it's the one you have to dive for most often.

The Direct routing system works exceptionally well, and in addition to extending the mixer for work with 16 and 24-track machines, it also allows the user to opt for a minimum signal patch when only one channel needs to be fed to one tape track.

The fact that the EQ and some of the aux sends are assignable means that on mixdown the number of useful inputs is doubled and that's not counting the four EQ'able stereo returns, which may also be used as additional line inputs.

The MIDI muting uses a serial/parallel dual-FET switch circuit which provides very good off isolation and enables the switching to be made soft to prevent clicking. Essentially, the switches turn on and off over a period of several milliseconds which has the effect of a very fast fade in or out. Purists will argue that such FET circuits introduce a little harmonic distortion while switching, but the period of switching is far too short for that to be noticeable, and it is certainly a better option than a click should you switch while a signal is present.

The MIDI muting system is reasonably straightforward, and the concept of using Controller information to update the console when starting a sequencer-driven mix part way through a song is a good one, even though it does take up a little more sequencer memory. Those with insufficient memory can opt to choose a longer catch-up time by setting the Controller information to be less frequent, or it can be turned off altogether leaving the mutes running purely on note information. I also like the fact that mutes are provided on four of the Aux sends.

For simpler mixes, the on-board snapshot system works fine, though a footswitch option to step through the patches might have helped — and for very simple mixes, the ability to assign up to four snapshots directly to buttons provides a quick and effective solution.


No mixer ever built is right for everyone, but given its price and features I feel that Studiomaster have come up with a very competitive product that delivers a hell of a lot of mixing power at a very low cost. By adopting the in-line format and adding the Group Direct buttons, Studiomaster have ensured that recording is not limited to 8-track but could easily be extended to 16 or 24-track — ideally by adding one or more expander modules for 24-track use. Indeed, the very expandability of the P7 gives it the edge over some of its competitors as nobody likes to have to sell a piece of gear when all they really need is the same but bigger. Fitting the expander modules is a simple DIY job — even an editor could do it — though it can be undertaken by a dealer if you feel unsure.

The security number feature is novel, though its value as a deterrent relies on potential thieves knowing it is fitted — there's no external warning. Though there are relatively few combinations, the time-out feature makes it difficult to hack and there's no simple hardware bypass either.

The more cynical might say the P7 is trying to cash in on the market opened up by the Allen and Heath G3 and Soundcraft Spirit Studio — the cosmetics certainly lean that way — but the circuitry inside is pure Studiomaster.

True, Studiomaster are late in embracing the in-line monitor concept, but I'm sure they've had their own reasons for taking their time and it has allowed them to learn from other people's mistakes. Whatever the reason, this is a very impressive mixer at a very attractive price. At the time of writing, Studiomaster denied that they were working on an automated version of the P7 — but then they would, wouldn't they? A P7 with fader automation would certainly be an attractive product.

Further information

Studiomaster P7 £2583.82 inc VAT.
8-channel expansion modules £969.38.

Studiomaster, (Contact Details).


FOR: Vice-free muting system; assignable EQ; expandability; no PSU noise; well though-out audio path; security function.

CONS: No scene change footswitch option; styling is a little "me too".

COMMENTS: A surprisingly good performer with plenty of routing flexibility and a practical MIDI muting system. Ideal for the home studio owner on a budget who wants lots of inputs and good basic sound quality at minimum cost.

Also featuring gear in this article

Previous Article in this issue

The Orb

Next article in this issue

Optical: Illusion Or Reality?

Sound On Sound - Copyright: SOS Publications Ltd.
The contents of this magazine are re-published here with the kind permission of SOS Publications Ltd.


Sound On Sound - May 1993

Gear in this article:

Mixer > Studiomaster > P7

Review by Ian Gilby

Previous article in this issue:

> The Orb

Next article in this issue:

> Optical: Illusion Or Reality...

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