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With Bruno Putzeys on the team, amplification would obviously involve class D. In the current LS1 production run, Ncore modules deliver around 120 watts per driver to render the LS1 internally bi-amped. With the 400-watt UcD-powered LS1s added, the system becomes actively tri-amped. So we arrive at a wide-baffle fully active phase-coherent three-way studio monitor. Unlike most studio monitors however, the LS1 does not look like a pro speaker. The combination of shallow cabinet, slender legs and blond wood make this loudspeaker very salonfähig and of modest dimensions at 115cm height, 16cm depth and 52cm width. This is not yer average big black ugly pro box. But it is a monitor intended for professional use in a recording or mastering studio.


So we asked ourselves, what makes a monitor a monitor? A studio monitor is designed to be honest to the bone and accurate only to the input signal. Placement should be easy and allow it to go on top of the mixing console thus parked in the near field. Larger monitors often end up built into the front wall. Coloration is shunned, active bi-amplification preferred and ruggedness mandatory. The studio space should have no influence on the sound the engineer works with. When such a studio monitor gets transferred to a home environment however, it soon appears to be too directional, needs to be driven too hard and exhibits problems with room interference. In short, a loudspeaker designed for a pro studio should stay in the recording studio. Know thy place!

With Grimm Audio’s much subtler styling not least by deploying that wide baffle, the LS1 on paper would seem suitable for use other than just the recording studio which already embraces this design wholeheartedly. The wide baffle claims that it’s possible to create a private bubble which keeps the rest of the room out. If and how much of that quality would be factual was going to be our assessment when Eelco and Guido brought over a pair of LS1 with LS1s subs to our place. The large box containing both disassembled LS1 speakers filled the back of Guido’s Citroen Xantia to capacity. Two other boxes with the subwoofer and a third with auxiliary accessories completed the delivery. Just like with any Ikea assemblage, we first laid out all the bits and bobs on the floor to get an idea of what was what. A clear assembly guide with adequate pictures made putting the speakers together easy. Our loaner had all metal parts except for the bottom plate sprayed in a brown paint that gelled with the cabinet’s light bamboo veneer in surprisingly attractive fashion.

For assembly it was advised to place the speaker cabinet flat on a table. Now check the serial number of the cabinet and that on the intended legs to be attached. They should match as one of those legs contains the firmware settings which match that particular pair of drivers. Remember the mild DSP. Make sure the connectors at the bottom of one leg faces in the desired direction and that the cable with the 6-pin connector dangling from the cabinet’s bottom sits on the correct side as the active leg has the corresponding receptacle. After connecting the cabinet to the active leg, both legs can be aligned and snap to the cabinet’s metallic sides with three powerful neodymium magnets. And when we say powerful we mean really powerful. For extra insurance a screw is provided to lock the top of the cabinet to the legs. On their tops two further magnets grab the semi-circular cover lid.


With both legs affixed, the heavy bottom plate bolts on next to provide stability once everything goes vertical but also to rigidify the entire construction. Repeat for the other channel. [Fact-checking the review prior to publication, Eelco added that the bottom plate has since grown thicker and heavier and now has provisions for mounting spikes.] Now we moved the speakers to their approximate final locations. There they would receive their subwoofers. Each fits nicely between the legs and contacts the base plate directly without any viscoelastic damper. The Grimm LS1 sets up in a master-slave config. The master speaker receives the source input signal and transfers the other channel data to the slave via CAT5 wire to eliminate conventional speaker cables. The CAT5 wire specifications relies on four twisted pairs to minimize crosstalk. RJ45 plugs terminate that cable.

Connection was easy. First we made provisions for the power supply. From the wall we ran a Grimm power cord to the IEC input of each subwoofer. These are equipped with not just a power inlet but outlet as well to power the monitor via a short power loop cable. Next we ran a length of CAT5 from the designated left master speaker’s Digital Thru/Control Thru connector to the right speaker’s Digital in 2/Control In receptacle. As we only had two speakers, the chain now had to be terminated with the provided RJ45 loop-back connector (the CAT5 connectors also accept Neutrik Ethercon plugs for an even sturdier connection). A short balanced cable connected both LS1 via their Sub Out XLR to the corresponding subwoofer.

For sound we decided to go all digital to start with. As a result the channel switch had to be set to correspond to the inputting speaker’s left/right location. The LS1 arrives with software whose latest iteration can be downloaded from Grimm’s website. This enables the user to configure the system and perform basic control tasks such as volume setting. For setup communication between computer and LS1—Mac or PC—two converters were needed at the time of our review. Subsequently a single USB/CAT5 interface box with precision clock became available. We still had to connect a USB/MIDI converter which then connected to a MIDI/CAT5 converter. It seemed a bit awkward but save for the extra box and cables, it worked without a hitch.

With the latest version software running on a laptop, we started to configure the LS1 system. As it was originally designed for professional use, some software features are not directly applicable for home audio purposes. However some fiddling with for instance subtracting overlapping left and right channel signal called side and thus only having differential stereo data at hand was enlightening. The very first thing to do was set the volume to a low value. You never know. Left and right settings, balance and studio matrix-related reference settings were left at default. Under the mute button exact channel-specific attenuation values are added. The zoom function is intended to detect noise and hum during recording sessions and adds an extra 20dB of gain whilst active. The dim function attenuates by 10 or 20dB depending on setting. Under the software’s general tab one selects the proper MIDI driver for one’s Mac or PC.


It also assigns Sim button functionality. This can simulate a small or ported speaker, a feature clearly intended as a mastering tool for pro audio. The LS1 tab offers left/right or inverted settings and an excursion limiter to protect the drivers from damage caused by extreme signals with an adjustable LED indication. The next setting proved crucial. We already mentioned the ‘bubble’ type dispersion which Grimm is about. With the Toe-in Angle setting the type of bubble becomes selectable. Here we have the preferred 45° value or an alternate normal 30° hifi angle. The 45° setting creates a wide sweet spot as the left/right speaker outputs cross 50 - 100cm prior to the traditional sweet spot. [Eelco added that a software revision downloadable from the website has since made some minor changes whose screen shots might differ from ours.]

Settings for analog input attenuation, low-cut frequency (40Hz default), bass boost and the brightness of the white LED which forms the dot on the ‘I’ of the laser-cut logo at the front of the LS1 cabinet can be made as well. All parameters are saved in the LS1 master’s memory together with the appropriate firmware. In order to integrate a subwoofer to perfection another software tab offers corresponding adjustments.


Next to No-Sub there is a choice for the LS1s Grimm sub or a third-party version. Choosing the Grimm sub automatically sets gain to 0dB, delay to 0 milliseconds, crossover frequency to 80Hz and low-cut to 20Hz. For non-Grimm subwoofers these parameters can be changed as desired. The final settings concern the remote for just two selectable parameters - display brightness and either dim or mute when the assigned button is pressed.


This remote is special and not your average off-the-shelf generic infrared. It’s a hard-wired wooden box with a large LCD display and equally large multi-function wheel on top just a bit like a giant iPod scroll wheel. Once operational, the Mac or PC used during the configuration phase should be disconnected whence the now vacant CAT5 socket connects the remote.


With the since launched USB interface this need for swapping became obsolete. All major remote functions are at the user’s disposal but the most used is obviously the volume control. But that’s not all. This remote is more than just a remote. Its inputs also provide computer audio relief from Mac or PC. All source signals get routed via the CAT5 output to the LS1 master unit. From this it must be crystal that source location is expected to be near the listener, i.e. at the side of the room and not between the loudspeakers. Else a cable snake pit is the inevitable result. However it’s possible to control the remote by remote. This only reads funny as the hard-wired remote accept control from a standard IR remote. We however preferred to use Grimm’s large physical wheel.