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GRIMM Audio LS1c & SB1 DSP Speaker Review

Rate this speaker system:

  • 1. Poor (headless panther)

    Votes: 10 3.2%
  • 2. Not terrible (postman panther)

    Votes: 20 6.4%
  • 3. Fine (happy panther)

    Votes: 112 36.0%
  • 4. Great (golfing panther)

    Votes: 169 54.3%

  • Total voters
    311

amirm

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This is a review, listening tests and detailed measurements of the GRIMM Audio LS1c active DSP speaker and its companion SB1 subwoofer. It was sent to me by the company. Speakers cost US $26,500 in the tested finish (pair). Companion SB1 sub costs US $12,750 for the set, brining the total to $39,250 (other finishes cost a bit more/less).
GRIMM LS1c Studio Monitor Speaker active dsp sb1 subwoofer review.jpg

This is one gorgeous and unique looking speaker! It nicely crosses the bridge between bland studio monitors and home speakers. Innovative mechanical engineering is employed to ship the speaker safely in multiple parts that you put together. Clever things such as magnets on side columns that attach to the sides of the main unit put a smile on your face. As does the SB1 subwoofer which tightly slides into the bass of the speaker, making it look like it is built in. Grill is provided for it although probably still not safe with kids and pets around.

Here is a closer look at the sub:
GRIMM LS1c Studio Monitor Speaker SB1 Subwoofer Review.jpg


The wiring is optimized for the sub with short cables provided to pass both digital data and power:
GRIMM LS1c Studio Monitor Speaker AES EBU Signal Path IO Measurements.jpg


Control ports can actually carry digital data which is the utilized to complete the system with LS1i USB which as a DSP bridge and configurator:
GRIMM LS1c Studio Monitor Speaker Anechoic LS1i USB controller streamer dac.jpg

Plug the this into the USB port of your computer and it shows up as a DAC. A control panel then provides simple interface for changing inputs and such. On that front, on my high dpi laptop, the buttons overlapped a bit. There was a bit of work also to figure out that this is what you have to do to select inputs. I wish there was a physical selector on the speaker so I could do that easier.

Both the speaker and subwoofer are sealed. Amplification is provided courtesy of Hypex amplifiers.

One of the problems using studio monitors with digital audio is how to handle volume control. GRIMM nicely solves that with the LS1r controller:
GRIMM LS1c Studio Monitor Speaker AnechoicLS1r remote controller volume review.jpg

The rotary controller is a joy to use. I would sit there and keep adjusting the volume for the fun of it. :) I understand there is a remote control which I did receive. The long included locking RJ45 cables do the job but deter from the clean look of the system.

These are optional extras. LS1i USB costs US $1,200 and the LS1r, $US 1,650.

While it is possible to use the speaker in 2-way configuration, I went for the 3-way setup with the SB1 subwoofer. System was tested as a whole on Klippel Near-field scanner. I have shared my measurements with the company but have not heard of they see any issues with them.
EDIT: Company responded post review here: https://www.audiosciencereview.com/...dsp-speaker-review.63015/page-33#post-2319711

GRIMM Audio LS1c and SB1 Subwoofer Measurements
As usual, we start with our computed anechoic family of frequency responses:
GRIMM LS1c Studio Monitor Speaker Anechoic CEA2034 Frequency Response Measurements.png

Other than some tiny variations, the on-axis response is almost perfectly flat. We can see that the blue early window directivity is essentially a copy of that, with a tinies of dip at crossover frequency of 1.5 kHz. There is little droop in that, or the power response for that matter, implying wide directivity (shown later). Usually with good directivity, we sacrifice wide response but we seem to have both of them here, indicating some clever engineering.

Here is the early window broken out:
GRIMM LS1c Studio Monitor Speaker Anechoic CEA2034 early window Frequency Response Measurements.png

If you want to reduce the slight dip, use a ceiling absorber or have high ceilings.

The combination of flat on-axis and similar early window results in excellent predicted in-room response:
GRIMM LS1c Studio Monitor Speaker Anechoic CEA2034 Predicted in-room DSP Frequency Response Me...png

Typical of studio monitors, the slope is rather shallow. Will be interesting to see if the speaker gets penalize for this in the preference score.

Near field response of the drivers shows very good response with only stand-out being low level resonances from the sub:
GRIMM LS1c Studio Monitor Speaker driver subwoofer Frequency Response Measurements.png


Distortion is very well managed both at 86 and 96 dBSPL:
GRIMM LS1c Studio Monitor Speaker THD Distortion DSP Measurements.png

GRIMM LS1c Studio Monitor Speaker THD Distortion Percentage DSP Measurements.png


I went up to 100 dBSPL and all of a sudden, saw a new resonance:
GRIMM LS1c Studio Monitor Speaker THD Distortion DSP 100 dBSPL Measurements.png

It may be a measurement, error, I am not sure. The sweep certainly sounded clean still.

As noted, directivity is quite wide, probably the widest I have measured:
GRIMM LS1c Studio Monitor Speaker horizontal beamwidth Measurements.png


Woofer nicely blends into the tweeter, after which it starts to beam somewhat. For most of the range, you have similar levels of response to sides of the speaker and then some!
GRIMM LS1c Studio Monitor Speaker horizontal directivity Measurements.png

The round edges essentially eliminate diffraction errors as evidenced by clean (relatively speaking) trend from red to white. Little jaggedness is to be seen.

Vertical has the similar issues of 2-way speakers although by placing the tweeter below woofer, you are much more likely to be sitting at optimal angle:
GRIMM LS1c Studio Monitor Speaker vertical directivity Measurements.png


The shocker, in a good way, came in the form of waterfall:
GRIMM LS1c Studio Monitor Speaker CSD Waterfall Measurements.png

As you see, the response stops on a dime and that is that. I don't think I have ever tested a speaker that was this good.

And fans of step response can rejoice in how the overall response is as if there is only one driver player:
GRIMM LS1c Studio Monitor Speaker Step Response DSP Measurements.png


GRIMM LS1c & SB1 Subwoofer Listening Tests
Due to size and weight of the speaker system, I chose to listen to it in our living room as opposed to dedicated music space. This is a very large space with 30+ feet ceilings. It is also highly reflective. Boy did the combo shine in this environment. I always start with female vocals and here, I was hearing an effect I had not experienced before: the vocals would separate out tonally and spatially from the rest of the band in the most delightful way. The halo was quite large around the (single) speaker I was listening to as well, making for a wonderful experience. This was still there somewhat with male vocals but really, there with females. Maybe it is the wide directivity. I am not sure but whatever it was, it put the LS1c+SB1 combo in a class by itself.

It is spring here and my allergies are bad which usually serves to reduce my high frequency response. That disclaimer stated, I found the tonality wonderful with zero need to modify anything so I sent the EQ team on a well deserved vacation. High frequency clarity was out of this world in the way those notes would shimmer and tell you they are there in only right amount.

Sub-bass response was fine meaning it was there with controlled/very mild level of distortion. Go up a few hertz though, and this SB1 would make you sit up and take notice. Not because it stood out but because while being fully integrated, it could pump out serious bass and upper bass notes that were ultra clean.

Despite evaluating just one speaker, I could sit there and listen for hours and hours. Indeed I did fair amount of that without either our dogs or my wife complaining! :)

Conclusions
It is a breath of fresh air to see a speaker be different from looks to functionality yet provide what we expect as far as ideal response. Not only the objective response is there, the combination of LS1c and SB1 delight this reviewer in ways he has not experienced. The integration provided through the external accessories it not to be underestimated in the way you can just plug everything and start playing and controlling the system without a glitch or any issues whatsoever.

Does the system look like a $45,000 one? Probably not. But the experience, considering that it includes everything you need from amplification to DAC and subwoofer, it within what can be justified. For some people at least, myself included. :) The number of times I have been sad to let a speaker go can be counted on one hand. One more finger was utilized to include the Grimm Audio LS1c system.

It is my pleasure to recommend the LS1c and SB1 subwoofer plus its control accessories.
------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Attachments

  • Grimm LS1c and Sb1.zip
    61.2 KB · Views: 115
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LS1- Technical Specifications

Audio inputs: 1 x stereo analog line level 3 x AES/EBU 44.1- 192 kHz 1 x USB: PCMupto384kHz/24bit (DXD), DSD64 & DSD128
Frequency response: 20 Hz- 20kHz+/-3dB (unsmoothed!) 30 Hz- 20kHz+/-0.5dB (unsmoothed!)
Deviation from minimum phase: <10 degrees
Amplifier power: LS1 250 &100Watt (per side), LS1s Sub 500 Watt (per sub), SB1 Sub 500 Watt (per sub)
MaximumSPL: 105 dB
Signal to noise ratio: 114dB (unweighted)
Height, width, depth: 1150mm x 520mm x 160mm
5 year limited warranty on material and workmanship

No specs supplied for SB1
 
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Here is my take on the EQ.
Please report your findings, positive or negative!

For the score rational your journey starts here
Explanation for the sub score
The following EQs are “anechoic” EQs to get the speaker right before room integration.
If you able to implement these EQs you must add EQ at LF for room integration, that is usually not optional… see hints there.

The raw data with corrected ER and PIR:


Score no EQ: 5.5
With Sub: 7.3

Spinorama with no EQ:
  • not smooth
  • some directivity error
Grimm LS1c No EQ Spinorama.png


Directivity:

Better stay at tweeter height
Horizontally, better toe-in the speakers by 10/15deg and have the axis crossing in front of the listening location, might help dosing the upper range.

Grimm LS1c 2D surface Directivity Contour Only Data.png
Grimm LS1c LW data.png



EQ design:

I have generated two EQs. The APO config files are attached.
  • The first one, labelled, LW is targeted at making the LW flat
  • The second, labelled Score, starts with the first one and adds the score as an optimization variable.
  • The EQs are designed in the context of regular stereo use i.e. domestic environment, no warranty is provided for a near field use in a studio environment although the LW might be better suited for this purpose.
  • Already has a sub...

Score EQ LW: 6.3
with sub: 7.5 (?)

Score EQ Score: 6.9
with sub: 7.8 (?)

Code:
Grimm LS1c APO EQ LW 96000Hz
May202025-101758

Preamp: -4.10 dB

Filter 1: ON HPQ Fc 26.6 Hz Gain 0.00 dB Q 1.35
Filter 2: ON PK Fc 59.9 Hz Gain 2.60 dB Q 1.05
Filter 3: ON PK Fc 1807.5 Hz Gain 0.78 dB Q 0.98

Grimm LS1c APO EQ Score 96000Hz
May202025-101758

Preamp: -4.10 dB

Filter 1: ON HPQ Fc 25.0 Hz Gain 0.00 dB Q 1.49
Filter 2: ON PK Fc 62.2 Hz Gain 3.04 dB Q 1.06
Filter 3: ON PK Fc 1469.6 Hz Gain 1.02 dB Q 1.31
Filter 4: ON PK Fc 5489.9 Hz Gain -1.27 dB Q 0.92

Grimm LS1c EQ Design.png

Spinorama EQ LW
Grimm LS1c LW EQ Spinorama.png


Spinorama EQ Score
Grimm LS1c Score EQ Spinorama.png


Zoom PIR-LW-ON
Grimm LS1c EQ Zoom.png


Regression - Tonal
Grimm LS1c EQ Regression.png


Radar no EQ vs EQ score
Improvements?
Grimm LS1c EQ Radar.png



The rest of the plots is attached.
 

Attachments

  • Grimm LS1c APO EQ Score 96000Hz.txt
    262 bytes · Views: 76
  • Grimm LS1c APO EQ LW 96000Hz.txt
    209 bytes · Views: 81
  • Grimm LS1c 2D surface Directivity Contour Data.png
    Grimm LS1c 2D surface Directivity Contour Data.png
    490.4 KB · Views: 108
  • Grimm LS1c 3D surface Vertical Directivity Data.png
    Grimm LS1c 3D surface Vertical Directivity Data.png
    422.9 KB · Views: 98
  • Grimm LS1c 3D surface Horizontal Directivity Data.png
    Grimm LS1c 3D surface Horizontal Directivity Data.png
    416.1 KB · Views: 110
  • Grimm LS1c Normalized Directivity data.png
    Grimm LS1c Normalized Directivity data.png
    373.5 KB · Views: 111
  • Grimm LS1c Raw Directivity data.png
    Grimm LS1c Raw Directivity data.png
    617.1 KB · Views: 112
  • Grimm LS1c Reflexion data.png
    Grimm LS1c Reflexion data.png
    189 KB · Views: 117
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Pleased to see a good dsp use. Seas drivers are really good, specialy the excel rang is amazing. Do you have a picture of the sub woofer?
 
Very interesting, thanks.

One question:
The sub bass level is quite below.
Is there a way to push the Sub up a few dBs ?
Would that make it flater below 100Hz ?
 
BTW, compare my measurements to that of stereophile:

0425-Grimm1fig1-600.jpg

They really need to correct for their near-field response error (the bump). It makes speakers like LS1c look bad for no reason.
 
BTW, compare my measurements to that of stereophile:

0425-Grimm1fig1-600.jpg

They really need to correct for their near-field response error (the bump). It makes speakers like LS1c look bad for no reason.
Yes, I was just looking at this plot.
They explain the difference is the cut out frequency:
nearfield response of the woofer with the low-cut frequency set to 20Hz (red), 40Hz (black), and 100.2Hz (blue)

But if I understand it correctly, that's without the sub.

With the sub, that should be more like this:
0425-Grimm1fig2-600.jpg


As is, the low bass response in your plots is surprising for a speaker at this price.
That's why I'm asking.
 
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Design and measurements warrant a "great" rating. There is just that little issue of 40K that I can't quite dismiss. There are powered monitors out there that cost well under 10K including separate subs that perform as good as these. That lower extension these produce will probably also be an issue in most rooms since sub placement is fixed with these.
 
That lower extension these produce will probably also be an issue in most rooms since sub placement is fixed with these.
Oh the sub is not attached to the speakers. You can put them anywhere and use longer cables.
 
Clearly an excellent product, but there's a lot of strong competition at (and considerably below!) that stratospheric price point, e.g. a Kii Three BXT setup -- with its huge low end capability and highly advanced DSP -- goes for literally many thousands of USD or Euros less: Kii Three BXT with Kii Control
 
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I just wonder why they chose to not put a round over on the top of the speaker.
 
Oh the sub is not attached to the speakers. You can put them anywhere and use longer cables.
That is great but kind of defeats the purpose of my idea of what this speaker is supposed to be which is a semi full range smallish powered speaker. I think it succeeds at that and is very nicely done. Well at least until sticker shock sets in.:eek:
 
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