Grimm LS1 Speaker Series

“This speaker is explicitly for those who want the most neutral and transparent sound reproduction ... no corners were cut”

"The Grimm LS1be will blow you away. Supremely realistic, it may be the end-game speaker you have been yearning for!"

General Introduction

A good monitor combines a high degree of accuracy with untrammeled musicality. There aren’t many of those around – common wisdom has it that you can have one or the other but never both. The LS1 is the first monitor to prove conventional wisdom wrong.

By integrating top quality digital signal processing, converters and amplifiers in one of the speakers’ legs, we were able to apply technical strategies no one had used before. As a consequence, the LS1 is not just a loudspeaker, but a complete audio system that only needs an analog or digital line source to perform.

True accuracy is about getting all the bits in the right place: not losing anything, not adding anything either. The LS1 offers this accuracy, reproducing a truly musical recording accurately, with all beauty intact. At the same time, the LS1 will also reproduce any imperfection, giving you all the information you need to get it right. These qualities make the LS1 an ideal monitor for both mastering and mixing.

Looking at the design, the box is much wider than it is deep, the small (14 litres) sealed box is designed to provide an effective baffle down to around 250Hz. It is suspended between two half cylinders that combat diffractions and function as an integral two-legged floor stand. An 8” magnesium woofer and a 1” dome tweeter divide the work between them. Smart use of DSP via a Computer Aided Calibration process during production linearizes the frequency response and allows for a controlled bass response down to 35 Hz.

Housed in one of the two legs are a 48/76-bit DSP, digital I/O, AD/DA, the same clock circuit as our CC1 master clock and the drive electronics, encompassing two 180W Class D power amplifiers of the groundbreaking Hypex NCore type.

Housed in one of the two legs are a 48/76-bit DSP, digital I/O, AD/DA, the same clock circuit as our CC1 master clock and the drive electronics, encompassing two 180W Class D power amplifiers of the groundbreaking Hypex NCore type.

The concept of the LS1 draws maximum benefit from intelligent application of DSP technology. An IIR crossover imposes exact LR4 acoustic slopes crossing at 1550Hz, and the phase is subsequently corrected using an idealised inverted all-pass filter, resulting in a maximally linear phase response without any pre-echo’s. This removes the “digital loudspeaker sound signature” typical of the more ubiquitous impulse inverted FIR designs.

Despite their compact size, the floor standing speakers are clearly intended as main monitors in mastering studios and mixing rooms that have space to put free-standing speakers. The DSP controlled analog subwoofer output allows for easy integration with stereo subwoofers, for those that need high SPL performance below 40 Hz. By selecting our SB1 or LS1s subwoofer, perfect integration with the main system is obtained, effectively turning the LS1 into a threeway system. The MU1 music player or LS1r remote offer convenient control of all functions inside the LS1.

The LS1be

The Audiophile Reference Flagship

Our new flagship product LS1be takes the already impressive performance of our LS1v2 loudspeaker to the next level.

Our aim was to improve transparency even further by focussing on “authority, control and flow”. To achieve this we worked on lowering distortion and extending the linear audio band. We added a new Beryllium tweeter, which was co-developed with Seas. It extends the frequency range and has 9 dB less distortion than our original tweeter. Furthermore we lowered jitter, improved the power supplies, employed some exclusive component selection and decided on silver power supply wiring for the finishing touch.

“We improved transparency even further by focussing on “authority, control and flow”.”

At the low end of the frequency spectrum, we obtained an even bigger improvement. Our newly developed Digital Motional Feedback SB1 subwoofer has an impressive 30 dB lower distortion, which means the bass area is now just as transparent as the mid and treble.

Of course, just like with our other LS1’s, the LS1be frequency response is linearized through smart use of DSP via a Computer Aided Calibration process during production.

The LS1be can be controlled by the MU1 music player, or by the LS1r controller and the LS1i USB interface, well known from the LS1. The cabinet can be ordered in a stylish ‘Hi-Macs’ artificial stone finish or in our traditional bamboo veneer look.

The LS1a

The Studio Monitoring Solution

The LS1a offers our LS1 series quality at a reduced price. All LS1’s embody our vision that ultimate sonic transparency can only be reached by integrating all components of the playback chain into one system. Only then, we have full control over the interaction of electronics, loudspeaker units and the acoustic behaviour of the cabinet. Grimm Audio’s deep knowledge about circuit design and component choice can then be optimally exploited.

“The LS1a possesses all the essential qualities and therefore performs at a true reference level in all key areas.”

By making some rational choices we were able to offer this quality at a significantly reduced price.

Compared to the standard LS1, the LS1a has a non-magnesium woofer, a lighter foot plate, a lacquered cabinet, plus we skipped some of the labor intensive modifications and the individual acoustic calibration of each LS1 cabinet.

What stayed are the low distortion and extremely linear amplitude and phase response (achieved through Computer Aided Calibration during production). And of course the form factor that makes positioning close to a wall possible without wall reflection interference.

The LS1a has versatile connections for analog and three digital AES/EBU sources. With the optional USB audio interface, any computer can become your audio source. The LS1r controller or a MU1 music player allow for convenient control of volume and source selection.

An LS1a covers the full frequency range as an elegant two way system. By adding an LS1s or even SB1 subwoofer set, the LS1a becomes a very low distortion three way loudspeaker that can handle all music styles in any size room.

This speaker serves as the ideal reference for artists and music lovers alike.

LS1be Features

Magnesium Seas woofer

Unique wide dispersion Beryllium tweeter

Unidirectional down to 250 Hz

DSP controlled frequency curve

Well-behaved off-axis response

Digital and analog audio inputs

64/128 fs DSD & DXD playback via USB

Filtered analog subwoofer output for SB1

Remote control of volume and source

Super low distortion NCore Class D circuit

Optimised NCore amplifiers

Upgraded components

Heavy footplate

Hi-Macs™ cabinet

Bamboo or lacquer finish

Optional Nano legs version

5 year limited warranty

LS1v2 Features

Magnesium Seas woofer

Seas DXT tweeter

Unidirectional down to 250 Hz

DSP controlled frequency curve

Well-behaved off-axis response

Digital and analog audio inputs

Filtered analog subwoofer output
Fail safe excursion and thermal limiter

Remote control of volume and settings

Super low distortion NCore Class D circuit

Optimised NCore amplifiers

Heavy footplate

Bamboo or lacquer finish

Optional Nano legs version

5 year limited warranty

LS1a Features

Polypropylene Seas woofer

Seas DXT tweeter

Unidirectional down to 250 Hz

DSP controlled frequency curve

Well-behaved off-axis response

Digital and analog audio inputs

Filtered analog subwoofer output

Remote control of volume and settings

Super low distortion NCore Class D circuit

NCore amplifiers

Lacquer finish

Optional Nano legs version

5 year limited warranty

Grimm Subwoofer Series

SB1 Subwoofer

The SB1 is a technological marvel. By applying Digital Motional Feedback’, a control technology from the renowned Dutch high-tech industry, it became possible to achieve exceptionally low levels of distortion and full dynamic control.

At frequencies below 100 Hz loudspeaker drivers need to move a vast amount of air and therefore have high excursion levels. The result is that all conventional loudspeakers exhibit a rising distortion in the bass region. In electronics, feedback is used to minimize distortion.

To apply feedback in electromechanical systems like an active loudspeaker, an acceleration sensor needs to be mounted on the cone to monitor its motions. This so called “Motional Feedback” technology has been presented a few times before in history but the
precision and control as found in the Grimm Audio SB1 is unique.

By applying smart digital processing and current drive, the low distortion of the already high-performance aluminum woofer is further reduced by as much as 30 dB, solving all problems that are related to low frequency resonances and distortion.

LS1s Subwoofer

Adding the LS1s sub to an LS1 turns it into a unique phase-coherent three-way system.

Although the LS1 on its own can play down to 40Hz with quite impressive power, the bottom octave down to 20 Hz is hard to reproduce with a two-way loudspeaker system. A dedicated driver for frequencies below 70 Hz solves this.

The low system distortion offered by the LS1s will appeal to those who like to listen at higher sound levels and to those who are in search of low distortion in general.

As a bonus the LS1s sub can be taken off the footplate and placed in the optimum position for low frequency reproduction, which is not necessarily also the optimum spot for the main loudspeakers.

The LS1s is based upon a very high quality Peerless
woofer and a 500W Hypex amplifier.

Digital Motional Feedback in the SB1 offers exceptionally low levels of distortion.

Rob Munnig Schmidt, designer of DMF

LS1 Series Specification

Audio inputs :
1 x stereo analog line level
3 x AES/EBU 44.1 - 192 kHz
1 x USB: PCM up to 384kHz/24bit (DXD), DSD64 & DSD128
Frequency response :
20 Hz - 20 kHz +/-3dB (unsmoothed!)
30 Hz - 20 kHz +/-0.5dB (unsmoothed!)
Deviation from minimum phase :