GRIMM Audio LS1c & SB1 DSP Speaker Review

[Hayabusa]

The woofer is a Seas Excel W22. The tweeter a Seas 27 DXT (H1499).
The subwoofer is 10". It looks much like a Dayton RSS series driver. But could be something else.

And the subwoofer has a piezo accelerometer for the digital motion feedback.

 

[Pearljam5000]

Apparently there are 2 types of subs

 

[Davey]

And the subwoofer has a piezo accelerometer for the digital motion feedback.

Yes, which could be attached quite easily to an off-the-shelf driver that doesn't have one.
This driver could be something different. But that's what it looks like to me.

 

[Robbo99999]

KEF does something similar in many of its speakers to account for room gain. A strategic move to maybe help users get reasonably flat bass without EQ.

Yeah, it was the only logical reason I could see for that kind of a roll off. It does make the bass distortion measurements look better than they really are though here in this review, because the bass is just not on the same level of other speakers that are flat down to their more aggressive roll off point. So if you were being fair you'd bump up the response of the subwoofer part to be more anechoic flat and the distortion measurement of the bass under those settings would then be more comparable to other reviewed speakers in my eyes. I'm therefore thinking we shouldn't get too excited about how this speaker/sub measures for distortion in the bass.

EDIT: just read Amir's following post:

No. The "subwoofer" in this speaker is not a traditional sub. It is a component that becomes part of the speaker, taking it from 2-way to 3-way. Indeed, that is how you configure it in the software. As such, I tested it like any other full range speaker. In the case of the measurements, the speaker is 5 foot above the floor so even near-field, non-anechoic response is going to show response that is closer to anechoic than otherwise. Also, in that near-field graph, I adjust the height of each driver. They actual levels are not correct. They are just a guess on my part (in this case, matching them to the crossover frequencies).

To the extent we test all speakers with deep bass response the same way, they can all be compared the same way. This is the purpose of testing. To take out the environmental effects.

The thing to pay attention to here is the integration of so called 'sub' with the rest of the speaker system. This is what GRIMM is bringing to the table which you would not have with a stand-alone sub.

Finally, I listened to the speaker and noted in the review that deep sub-bass is not there as there is in other full range speakers. What it plays is exceptionally clean but it is at higher bass frequencies.

Well in that case I take back part of what I said earlier in this post, as it seems it's designed not to play low and would indeed need a sub to be paired with it anyway if you wanted to play low. But still, my point about the amount of measured distortion of the bass holds true - the bass is rolling off from 100Hz so is at a lower level than many other speakers tested so the bass distortion measurements still look better than what they really are, so to speak, if compared to other speakers that attempt linear bass extension. The fact this expensive speaker kind of needs a sub makes it a bit more of a mockery, to use a cruel word, but it's super expensive, so.

 

[AudioKC]

Which monitors/ speakers come close to the

LS1C but cost much less?​

I would say https://www.neumann.com/

 

[Hayabusa]

Yes, which could be attached quite easily to an off-the-shelf driver that doesn't have one.
This driver could be something different. But that's what it looks like to me.

does not sound easy to me?

 

[olieb]

does not sound easy to me?

Well, probably because it is not.
Here is a White Paper from the guy who did it ("it" being the SB1).

https://www.rmsacoustics.nl/papers/whitepaperMFBdesign.pdf

and his page

Audio Design Principles

Audio Design Principles of RMS Acoustics & Mechatronics

www.rmsacoustics.nl

From that the driver is probably a modified Seas L26.
And no, not even choosing the sensor is easy, let alone attaching it, if you do not want to end up with a noisy, non-linear or resonating system.

 

[Davey]

does not sound easy to me?

Attaching the sensor is easy. Doing all the rest of the implementation is where the work is. Obviously.
The question here is.....why is the distortion performance of the SB1 not better.....considering all the effort put into this aspect of the design?

It could be an L26 driver. But that has an inverted cap, and the Grimm/Amir photo's show a non-inverted cap. Plus, the surround does not look quite as substantial as the Seas L26. That's what leads me to believe it's a Dayton driver.
I could be wrong.

 

[IngMishael]

Which monitors/ speakers come close to the

LS1C but cost much less?​

This comes to mind - https://aaltospeakers.fi/en/product/aalto-9/

Aesthetics may not be for everyone though

 

[kemmler3D]

if you were being fair you'd bump up the response of the subwoofer part to be more anechoic flat and the distortion measurement of the bass under those settings would then be more comparable to other reviewed speakers in my eyes.

I don't really agree, the bass is what it is (apparently not very strong) but the distortion is a reflection of what you would actually hear in use. "How much distortion would this speaker have if you EQ'd it" would make it harder to compare different speakers.

Also, I'm not 100% sure the distortion measurements would get worse if you EQ'd this thing. The roll-off starts pretty high even for a small "sub" like this, I wouldn't be surprised if it still had some excursion in the tank, being built from presumably nice drivers, in which case you could get more output but with distortion increasing slower than SPL and lowering the distortion percentage a bit, maybe between 50-100hz.

 

[bachatero]

Why does the sub perform so poorly? The KH750 is almost a tenth the price, also uses a 10" driver, but extends down to 22Hz at -3dB and has tons of fancy DSP features.

 

[OlsonSystems]

I have lusted after this speaker for years. Reading the white paper made me a fan of the wide baffle. Great to see this review. A few months ago I realized I had the parts required on my shelf and could modify one of my old speaker builds into this configuration. I loaded a stock DXT tweeter in place of the previously mounted midrange and tweeter in the baffle of my failed 2018 contest speaker. So in a few hours I had an ugly DIY version. Using a miniDSP and a couple of Dayton amps I was in business. The tweeters required several filters to get a flat response. Passive crossovers need not apply. I was pleasantly surprised with the first listen. I think this design may be the best sounding speaker I have yet to build. I used the PEQ filters in the miniDSP and haven't spent the time to develop FIR filters or employ the transconductance amps. The good news is that with a few thousand in parts (woofers are maybe $550 and tweeters are ~$100 at Madisound ) I was able to get what I think is a very enjoyable clone. I have yet to pair them with a woofer box. I hope to have a buddy build me a more elegant version of the enclosure as I'm not a skilled wood worker.

 

[thewas]

Looking at this photo I remembered that back when they were released Grimm used to toe them in at 45° in audio shows so the acoustic axes would meet in front of the listener, which would mean their measurement reference axis horizontally is at 15°:

Source: https://www.grimmaudio.com/wp-content/uploads/Manual-LS1-EN-V3.00.pdf

 

[Davey]

@OlsonSystems
That's a cool project. Well done.
If you build a follow-on version I would suggest centering the drivers so the polar response is symmetrical. And put the drivers closer together.
Something very much like this (except a dipole version) was considered by Siegfried Linkwitz about twenty years ago to improve the Orion design. (He ultimately went a different direction.)

 

[Vuki]

No. The "subwoofer" in this speaker is not a traditional sub. It is a component that becomes part of the speaker, taking it from 2-way to 3-way. Indeed, that is how you configure it in the software. As such, I tested it like any other full range speaker. In the case of the measurements, the speaker is 5 foot above the floor so even near-field, non-anechoic response is going to show response that is closer to anechoic than otherwise. Also, in that near-field graph, I adjust the height of each driver. They actual levels are not correct. They are just a guess on my part (in this case, matching them to the crossover frequencies).

To the extent we test all speakers with deep bass response the same way, they can all be compared the same way. This is the purpose of testing. To take out the environmental effects.

The thing to pay attention to here is the integration of so called 'sub' with the rest of the speaker system. This is what GRIMM is bringing to the table which you would not have with a stand-alone sub.

Finally, I listened to the speaker and noted in the review that deep sub-bass is not there as there is in other full range speakers. What it plays is exceptionally clean but it is at higher bass frequencies.

Grimm seems to be pretty serious company. Do you really believe they would declare frequency response of the speaker as "30 Hz - 20 kHz +/-0.5dB" if it measured like in this review?

 

[OlsonSystems]

Davey

www.audiosciencereview.com

I started with the drivers centered but then changed it up. The horizontal offset was carefully calculated to produce a very flat on axis response from the original speaker that used a very wide dispersion midrange that illuminated the baffle edges. With this offset the peaks produced by one cabinet edge are some what canceled by the dips produced by the other cabinet edge. With the 4" half round this is a very small effect. I will have to load this new configuration back into Boxsim or VituixCAD and see how it looks.

The woofer box wall prevented me from locating the tweeter in this mockup any closer to the woofer.

 

[beefkabob]

Ugh, I dislike when this talking point is brought up. As someone who plays piano, I can assure you that most piano repertoire does not use the lowest A. Further, the bass strings for the lowest notes on all but the largest of concert pianos have so much harmonics that you hear those more than the fundamental.

Still, at this price point I don't think it's unreasonable to expect this speaker to be able to cover down to 20Hz competently considering there is vastly cheaper equipment that can do so.

I know that most piano pieces don't use the lowest note, but the point stands that there is potential information, and often information, in the low end of bass for all genres. At least that's what my spectrum reader says.

 

[Heinrich]

Also, I'm not 100% sure the distortion measurements would get worse if you EQ'd this thing.

The room, the floor especially, will alter the output dramatically. It will lift the bass output, without increasing distortion.

I have lusted after this speaker for years. Reading the white paper ...

Our DIY buddies could simulate the outcome of a variety of possibilities. I would opt for a 8" bass, a 6" midrange, and a 1" tweeter a la DXT x/over at 1200Hz to at least gradually mitigate the problem with vertical lobing.
The secret sauce is not in the drivers ;-) A wide baffle speaker is best arranged against a backwall, an on-wall / at-wall speaker, left and right around a corner.

With this quite simple concept DIY really shines. And, not the least, Grimm would not lose their wealthy customers, to the contrary.

 

[kharan]

Why does the sub perform so poorly? The KH750 is almost a tenth the price, also uses a 10" driver, but extends down to 22Hz at -3dB and has tons of fancy DSP features.

It's about half the volume, what do you expect?

 

[beefkabob]

I know that most piano pieces don't use the lowest note, but the point stands that there is potential information, and often information, in the low end of bass for all genres. At least that's what my spectrum reader says.

I should add that a great way to tell is to put in filters on the sub, which is easy with certain SVS subs and the app. If I put a 24db filter to cut 40 hz down, I notice a difference in a lot of music. At 60hz it's a big difference. At 80hz it's a huge difference in pretty much everything. This holds true when the sub level is matched by ear but also when it's matched by Dirac.