GRIMM Audio LS1c & SB1 DSP Speaker Review

[richard12511]

Ugly, overpriced and bass shy are too big of negatives.
This radiation pattern is the star of the show, makes me very curious to listen to them in a large room, I don't expect them to be very at ease in a studio configuration, or is there something I'm missing ?
Big thanx to the company for sending these, and of course thanx to our master reviewer.

Strongly disagree on them being ugly. Aesthetic preference seems far more individual than sonic preference. For me, these(especially in white) are probably in my running for the most beautiful speakers I’ve seen.

 

[Newman]

Those large radius side round-overs primarily benefit the tweeter (though they are large enough to benefit the midwoofer as well).

Notice that the tweeter is below the midwoofer. Now look at the bottom edge of the main enclosure. THAT's where the round-over is! It's where it would do the most good for the tweeter! Rounding over the top of the speaker would not be as beneficial.

(Since they did not skimp on anything else, my guess is that Grimm either tested a prototype with the round-over on top, or at least modelled it, before deciding it was unnecessary.)

I would think that, by the time a perpendicular upward wave from the tweeter has encountered the cone and negotiated its irregularities, any edge treatment at the top of the baffle is pointless.

cheers

 

[dtaylo1066]

Always nice to see an expensive, high-end product perform with excellence. If I win the lottery....

 

[capslock]

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.

In the original LS1, that is. The be and c versions are not available to the public, and the face plate / wave guide has been changed to something without those huge screw holes, too.

I wonder if they still use the original W22EX or have changed to the newer motor on the Excel series.

 

[OlsonSystems]

Did you model the x-over close to the original design?

In my understanding such a 8"+1" concept is pretty sensitive to crossover design and baffle geometry, and any tiny change in the transitional band has huge impact on the sound quality. Grimm seemingly is using some asymmetrical-slope concept, maybe to get a smoother transition in directivity. Both drivers are operating at the limits regarding their behavior outside their designated range.

I did. I used the exact crossover frequency and slopes. There was a bit of filtering required to get the tweeter response flat to start with before applying the crossover filters as the waveguide boosts the low end. A few notch filters were required to really crush the cone and dome breakup resonances as well. I used a Linkwitz transform to adjust the low end response of the tweeter and adjust the Q to form half of the LR 4th order high pass.

Here's a plot of the raw woofer, woofer with EQ and crossover and tweeter with EQ and crossover. Gated response is only valid over 200 Hz.

 

[Heinrich]

Here's a plot of the raw woofer, woofer with EQ and crossover and tweeter with EQ and crossover. Gated response is only valid over 200 Hz.

Not an inquiry, but did you also measure vertical towards up and a little bit to the sides, horizontally?

There's so much theoretical talk about this speaker, if it is beautiful, and how bass shy it is in all its excellence on paper.

But is such a wide dispersion really desirable? It realizes +/-100° (-6dB) roughly, while a KEF R series would do +/-50°. And if I read it right, the LS1 was ousted by the Kii, cardioid etc/, same developer?

It may also raise the question if the more discriminative test listening in mono is as easy as it sounds ;-) Such a wide speaker ;-) would feel better to the ears due to many reflections, less sharp, less empty in comparison to again a KEF R series.

Not the least, to put a speaker into a well filled ;-) bookshelf might have a similar effect as the wide baffle. But that is an antiquarian idea ;-) me thinks.

ps:
- may it be worthwhile to exchange the ceiling bounce with the floor bounce and vice versa; could be done via a software update
- the wiggles in the nearfield bass response in higher frequencies may originate in the residuals from the midrange speaker
- bass response, if meant to be anechoic, is perfect for room integration; distortion taken in percentage will drop by a factor of two or more in-room, and bass mangement will ask for extra subs distributed around the room anyway, as always, and then equalize to individual taste

 

[Arindal]

Here's a plot of the raw woofer, woofer with EQ and crossover and tweeter with EQ and crossover.

Looks absolutely reasonable to me from the point of filters. As Heinrch mentioned, the important question is how it will behave under vertical angles, as the band in which woofer and tweeter are both influencing the off-axis response, is pretty broad. So the concept is very sensitive to phase behavior and baffle geometry, particularly the distance between woofer and tweeter.

But is such a wide dispersion really desirable? It realizes +/-100° (-6dB) roughly, while a KEF R series would do +/-50°.

The underlying concept is a wide but frequency-independent dispersion. That makes a lot of sense, if the room is treated accordingly, with reduced/delayed side wall reflexiveness being key to get an excellent result.

I would not express dispersion characteristics in degrees of a window, particularly not without stating the frequency band for which this is valid. The speaker you named might show +-50deg of listening window at 3K but something close to omnidirectional or +-180deg @500Hz and +-30deg @6K which are all relevant for perceiving reverb and reflections. The result will be a tonally imbalanced indirect soundfield which the Grimms avoids.

 

[mcdn]

It does strike me that the measured results are almost exactly what you'd get from a 10" sub driver in that enclosure size (15L or 0.5cubic feet?) with no DSP to boost the low end. f3 of 50Hz, f10 30Hz.

@amirm do you recall the extension setting you used? There are several available, maybe you had it on the highest one?

 

[berjine]

I would be curious to see it compared to the GGNTKT M1/M3, same idea of flat and wide dispersion but with cardoïd directivity as a bonus

 

[olieb]

But is such a wide dispersion really desirable? It realizes +/-100° (-6dB) roughly, while a KEF R series would do +/-50°. And if I read it right, the LS1 was ousted by the Kii, cardioid etc/, same developer?

I was contemplating the very same question. I own the R3 and I like it a lot. But you never know what you are missing, right?
The R3 has the better vertical directivity because of the coax, but the horizontal pattern is considered to be of more importance and the vertical lobing of the LS1 does not seem to be a problem. Horizontal directivity will dominate the earlier reflections and the later decay will be a result of power response.

I checked the numbers to get a better picture.
I averaged over whole octaves and looked for the angle where the SPL reached -3dB and -6dB in each band.
This is my result (from Amir's measurement numbers)

HORIZONTAL	Grimm LS1	Grimm LS1	Kef R3	Kef R3
frequency	-3dB	-6dB	-3dB	-6dB
0.5-1kHz	70°	100°	70°	120°
1-2kHz	70°	90°	50°	70°
2-4kHz	80°	90°	40°	60°
4-8kHz	40°	80°	30°	50°

So the LS1 is not only very wide but the horizontal polars are very close together too. Up to 4kHz the beam width is essentially constant! And above the speaker still is narrowing only a bit. The DXT is a heck of a tweeter.
And the higher directivity from the baffle down low does show too, even above 500Hz.
The difference is bigger than I thought (and than the full DI would have me believe).

So, is it desirable? Well I do not know. In mono certainly, in stereo possibly and it might depend on the room.

 

[Arindal]

I would be curious to see it compared to the GGNTKT M1/M3, same idea of flat and wide dispersion but with cardoïd directivity as a bonus

Have listened to all three over the course of a few weeks and they sound surprisingly different despite similar measurements and geometry.

My explanation would be that the compression-loaded horn of the GGNTKT and the dome tweeter of Grimm just sound fundamentally different. The other main difference is the directivity index with the Grimm being close to a huge baffle speaker with rounded edges while the GGNTKT combines broad baffle and cardioid cancellation which as a matter of consequence gets you a much higher (and pretty consistent) overall direcitivity index.

 

[tktran303]

Why is the harmonic distortion rather high in the sub-bass range? That I'm not so sure about. Puzzlingly, in the 60-100Hz range at 96dB, all harmonics seem to be 5-10dB higher than in Grimm Audio's measurements without the subwoofer module.

It’s never quite clear to me how the NFS calculates the harmonic distortion. I’m sure it uses an (exponential) sine sweep.
But does it in 3 seconds, 12 seconds or longer? And is the mic on the reference axis at at 1m?

I once asked Erin and it’s wasn’t clear how it was done. Perhaps it’s during the NFS’ routine and he’s away in another room?

I mean it the whole spin takes a long time; who could blame him for not sitting there and watching it through the process.

Whenever I take bass distortion measurements at 1m, it’s never quite the same as bass distortion measurement from a ground plane or anechoic chamber, or in the nearfield of the drivers.

It’s a quandary.

@amirm - have you ever observed where the mic is when the 86, 96 and +/- 106dB harmonics are measured? Is it a 10-20 second sweep at the beginning, during, or at the end of the NFS robotic test sequence ?

 

[Arindal]

the vertical lobing of the LS1 does not seem to be a problem.

It is seemingly not such a problem under mid- or far-field conditions in well-damped rooms and vertically predictable listening position. Under nearfield conditions, in a more lively room, particularly with ceiling reflections, or with listeners moving freely, it might come into play.

 

[Purité Audio]

I would be curious to see it compared to the GGNTKT M1/M3, same idea of flat and wide dispersion but with cardoïd directivity as a bonus

I have made that comparison, Only M1 although I would like the M3’s here.

 

[amirm]

It’s never quite clear to me how the NFS calculates the harmonic distortion. I’m sure it uses an (exponential) sine sweep.

The distortion measurements are separate from NFS. They are no different than using REW except that I can use the robotic system to precisely position the mic. The sweep length (hence frequency resolution), frequency range, repeat, etc. are all programmable.

 

[amirm]

@amirm - have you ever observed where the mic is when the 86, 96 and +/- 106dB harmonics are measured? Is it a 10-20 second sweep at the beginning, during, or at the end of the NFS robotic test sequence ?

Again, this process has nothing to do with NFS. All distortion measurements are performed manually using the base Klippel measurement system. I measure at 1/3 meter but report at 1 meter (Soundstage does something similar). This balances reduction of ambient noise/reflections vs amount of SPL the microphone is subjected to. Results are non-anechoic. You can convert them to anechoic using another process which to me, is a bit messy so I don't bother. As a result, it slightly exaggerates some of the low frequencies. My room is quite large so the impact is not that big (as it is in Erin's setup).

I have made profiles for 86 and 96 dBSPL. For any other, I create a new profile and run it as I did here at 100 dBSPL. Level setting is done manually and you sort of have to eyeball it if the frequency response is not flat. I focus on 1 kHz as long as it is close enough to either side of the spectrum.

Due to near-field measurement distance, I start at tweeter axis but find tune vertically to get the most flat response. This, and above level setting create variability.

In general, you can't compare absolute level measurements between different people doing it. They are for comparisons of measurements performed by the same entity. Unusual issues such as resonances, etc. can be compared however. And correlation tends to be Ok to good among some entities.

 

[Koeitje]

Very good loudspeakers, but there is some steep competition from D&D and Kii.

 

[Purité Audio]

Yup imho when Bruno offered the prototype ( what was to become Kii) they should have grabbed it with both hands, Ls1 is definitely a decent speaker but the 8Cs kill them and easier/better actually in room, plus Grimm decided to oligarch their pricing.
Keith

 

[mar1o]

Yup imho when Bruno offered the prototype ( what was to become Kii) they should have grabbed it with both hands, Ls1 is definitely a decent speaker but the 8Cs kill them and easier/better actually in room, plus Grimm decided to oligarch their pricing.
Keith

The 8C is undoubtedly a top speaker and has its advantages. But the wide, controlled dispersion characteristic also has its charm, if you like it. Finally, don‘t forget that the LS1 is now a fairly old design. But as you can see, it's still anything but bad. Rather the opposite. It would be particularly interesting to compare the individual variants to get an idea of whether there are any significant differences. Perhaps aa LS1a can hardly be distinguished from the other versions even in the double-blind test?

 

[IngMishael]

Have listened to all three over the course of a few weeks and they sound surprisingly different despite similar measurements and geometry.

My explanation would be that the compression-loaded horn of the GGNTKT and the dome tweeter of Grimm just sound fundamentally different. The other main difference is the directivity index with the Grimm being close to a huge baffle speaker with rounded edges while the GGNTKT combines broad baffle and cardioid cancellation which as a matter of consequence gets you a much higher (and pretty consistent) overall direcitivity index.

The GGNTKT M3 also has a much narrower in room slope which almost always gets forgotten in assessments. It is almost nearing flat on axis in terms of PIR