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Reviewer: Marja & Henk
Financial Interests: click here
Sources: PS Audio PWT; PS Audio PWD; Dr. Feickert Blackbird/DFA 1o5/Zu DL-103; Phasure NOS1 DAC [in for review]
Streaming sources: XXHighEnd; iTunes; Devialet AIR
Preamp/integrated/power: Tri TRV EQ3SE phonostage; Audio Note Meishu with WE 300B (or AVVT, JJ, KR Audio 300B output tubes); Yarland FV 34 CIIISA; Qables iQube V1; Devialet D-Premier; Hypex Ncore 1200 based monoblocks; Trafomatic Kaivalya
Speakers: Avantgarde Acoustic Duo Omega; Arcadian Audio Pnoe; Vaessen Aquarius
Cables: complete loom of ASI LiveLine cables; full loom of Crystal Cable cables; Nanotec Golden Strada #79 nano 3; Nanotec Golden Strada #79; Nanotec Golden Strada #201;
Power line conditioning: Omtec Power Controllers; PS Audio Powerplant Premier; PS Audio Humbuster III;
Equipment racks: ASI amplifier and TT shelf
Sundry accessories: Furutech DeMag; ClearAudio Double Matrix; Nanotec Nespa #1; Exact Audio Copy software; iPod; wood, brass, ceramic and aluminum cones and pyramids; Shakti Stones; Manley Skipjack; Blue Horizon footers [in for review]
Room treatment: Acoustic System International resonators, sugar cubes, diffusers
Room size: ca. 14.50 x 7.50m with a ceiling height of 3.50m, brick walls, wooden flooring upstairs, ca 7 x 5m with a ceiling height of 3.50m, brick walls and concrete floor downstairs.
Price of review item: €24,990 incl. 21% VAT for the 3-way, €17.990 incl. 21% VAT for the 2-way

Grimm Audio is a Dutch company who initially focused on delivering high-quality gear to the professional recording market. The name derives from Eelco Grimm, a sound engineer by profession who also teaches at the Media and Technology faculty of Utrecht’s School of the Arts. Because he had the best surname of all people involved, the company bears his name. Why a product from a pro company would now show up in the 6moons pages aiming at high-end music lovers you’ll discover reading on. Besides Eelco the Grimm team consists of the Tentlabs core members Guido Tent, Bruno Putzeys and Peter van Willenswaard. Tentlabs alone should ring a bell as they’re well known for their DIY modules of shunt regulators, precision clocks, CD player kits and the new b-line of turnkey components. Bruno Putzeys’ name is said in the same breath as class D, UcD and now Ncore. Peter van Willenswaard is officially retired but a source of great knowledge with vast experience in analog and digital audio. This core team is assisted by a group of both younger and more mature engineers whenever needed.

Guido & Eelco
Eelco’s passion for music and technology is the necessary glue which binds and steers this bunch of willful hardcore technicians in the right direction. Physical results from their collaborations can be found in many recording studios around the world and are highly praised. The Grimm Audio AD1 converter facilitates conversion of analog sources directly to the 1-bit DSD format at 2.844MHz. In a world of many such converters, the Grimm version sticks out by using discrete circuitry and no off-the-shelf converter chips. Other signature elements are the precision clock responsible for ultra-low jitter and the overall design which defeats all manner of electromagnetic interferences at the drawing board. A correct circuit board layout to start out with always beats fighting any EMI with subsequent patch-ups. Of course there are shunt voltage regulators and a choke-filtered power supply as well. Tentlabs, remember?


Unlike most pro designs, the AD1 is clad in wood. Besides this converter, there’s also the standalone clock module CC1. With this an entire studio setting can be synchronized at the lowest possible clock jitter rate. Grimm Audio’s experience with power supplies is found in the power supplies for various tubes microphones. To connect everything requires cables. In pro environments those do not come in 1 or 2 meter lengths. Thus quality and price are very different than what music lovers know or accept. Cable microphonics kill any recording as do unduly high resistance, inductance or inadequate shielding.

When the Dutch Wisseloord studios meant to  update their wiring, Grimm devised the TPR pro version of their existing TPM cables for high-end use. After experimenting with this cable in auditions, the studio ordered 50.000 meters—yes 50 kilometers—to completely rewire their facility. It must be obvious that high-end audiophile cables with their often exorbitant prices are anathema at such quantities. This also raises general questions about high-end cable’s actual quality but that’s a discussion for another day.

Back to Grimm Audio, they aren’t merely about high-quality hardware. Software too is an intrinsic part of their expertise and specific to the Level series of plug-ins for digital audio workstations aka DAWs and applications for Mac and PC. These software suites give insight into loudness levels or set loudness levels to normalized values. Here Grimm does not join the Loudness Wars which kill off recorded dynamics or better stated their crest factors. Quite the contrary, Eelco is a contributing member to a European Broadcast Union committee which drafts new rules which commercials and programs on radio and television should adhere by to refrain from deafening viewers and listeners alike.

This gets us to the subject of this article, the Grimm LS1 loudspeaker. It is here that everything mentioned above pools together. The LS1 is not merely a loudspeaker but an active loudspeaker system. To be fair, Grimm Audio more specifically terms it a monitor, not just a loudspeaker. This means that music produced by the speaker is to be completely accurate to the source. Accurate to the source also implies that it measures correctly. And we all know how claims about a piece of audio gear measuring correctly needn’t be synonymous with sounding good in a musical sense. Here Grimm counters by stating that the LS1 is “the first loudspeaker to combine utmost musicality with unprecedented accuracy”. To execute such a bold claim requires a strong hand. And that hand belonged to Bruno Putzeys who did most of the design and development work.

When Eelco and Guido delivered the LS1 loudspeaker system to us, they explained their philosophy about reproducing music in depth and in particular the role of the loudspeaker. It all starts with the ability of a speaker to accurately reproduce a recorded acoustical event in a different environment. The question is whether that’s a realistic goal. For a recording two microphones—for argument’s sake we’re talking stereo basics—sample a real three-dimensional sound field. After that signal passes through numerous electronics, two loudspeakers emit two interfering spherical sound fields. Our brain now interprets those two interfering fields as a combination of strongly correlated and decorrelated sound sources. Two strongly correlated sources make our brain think of a single fixed location. If the original recording puts one instrument slightly to the right, the associated correlated recorded data delude the brain into thinking that the instrument sits right of center. For the desired stereo phenomenon to arise relies all on psychoacoustics. Without the brain’s assistance there is no illusion (or imaging in audiophile lingo).

That’s one obvious challenge. The next is the room wherein playback takes place. All manner of early reflections and reverberations wreck havoc with the original signal. They add spurious cues that never existed in the original recording. Wearing his recording engineer’s hat, Eelco cited just one example of a big band whose soloist on duty points his instrument straight at the microphone. In the recording that soloist sounds nicely dry or direct against the wetter more reverberant indirect or reflected backdrop of the other brass instruments. When reproduced in the average listening room, things change dramatically. The room’s addition of early reflections and its own acoustic reverb signature completely alters the outcome especially with omnidirectional speakers.