GRIMM Audio LS1c & SB1 DSP Speaker Review

[amirm]

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?

They stated to me that their evaluation was non anechoic. Indeed their only measurement shows bass response as "simulated."

 

[bachatero]

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

But is it even half as good?

 

[Duke]

I just wonder why they chose to not put a round over on the top of the speaker.

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.)

Imo very innovative and well thought-out configuration, not to mention the superb execution of the concept.

 

[kemmler3D]

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.

+1 to this, I bring it up fairly often, inharmonic sounds often have significant content all the way down to 20hz. The fact that most instruments don't play notes with fundamentals that low doesn't mean nothing goes that low. Even cymbals have some content at 20hz if they're not highpassed.

 

[Sokel]

+1 to this, I bring it up fairly often, inharmonic sounds often have significant content all the way down to 20hz. The fact that most instruments don't play notes with fundamentals that low doesn't mean nothing goes that low. Even cymbals have some content at 20hz if they're not highpassed.

A "P" sung a certain way with close mic can reach as low as 15Hz.
So...

 

[Robbo99999]

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.

You only quoted part of my post, I had done an EDIT where I was referencing one of Amir's responses where he was saying it's not really a sub, it's just supposed to be in the same vein as a 3 way speaker, so I ended up taking back comment that the "sub" should be turned up, but I did still comment that distortion measurements in the bass are still misleading if you just look at them in isolation, because it's not really producing much bass in comparison to a lot of speakers as it's rolling off starting at 100Hz. So essentially I'm saying don't get wowed by the bass distortion results because it's not producing much of it to start with, which is disappointing for such an expensive product.

 

[bmc0]

Some are expressing doubts that the subwoofer module was active. I'm quite certain, based on the measurements, that the SB1 was in fact working. The clearest evidence is in the negative vertical angles:

Since the reference point is somewhere around the woofer and tweeter, the subwoofer is closer to the (virtual) mic for vertical angles around -90° compared to 0°. The level below ~50Hz rises accordingly, with the maximum being around -130° in this particular case.

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.

 

[audiotron]

Would you pick these over the Salon 2?

 

[kharan]

But is it even half as good?

Define good. I'm sure that with boundary reinforcement it is flat and offers enough bass and SPL for most rooms. And it does this without detracting too much from the general aesthetics of the speaker, it still looks like a stand as opposed to an extra box.

 

[Lars Risbo]

An additional interesting fact is that the bass is not omnidirectional in the same way in an anechoic chamber.

Here is an anechoic measurement (20-50hz) of a ported speaker. Drivers + port pointed at the microphone is in red, pointing away is in green.
Additionally, this speaker is typically flat to at least 25-30hz in-room, while in the anechoic measurement we see 10dB drop from 50hz to 20hz even when pointed at the microphone.

View attachment 452414

what distance was used? if far away then it should be fairly omni (higher order spherical modes decay very fast with distance )

 

[al2002]

For those interested in DIY motional feedback: https://piratelogic.nl/

 

[sigbergaudio]

what distance was used? if far away then it should be fairly omni (higher order spherical modes decay very fast with distance )

2 meters.

 

[Arindal]

I used the PEQ filters in the miniDSP and haven't spent the time to develop FIR filters or employ the transconductance amps.

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.

 

[olieb]

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.

What part of a wide, generously rounded geometry will be sensitive to small changes?
The crossover is LR4 plain and clean, augmented with a phase linearisation.
From Putzeys' White paper:

First, both drivers are EQ’ed flat (again, within reason) over a frequency window well beyond their final operating range. Next, LR4 filters are applied. I must confess to an unconditional preference for Linkwitz-Riley crossover filters. I find it amazing that for an art like crossover design that has been practiced for so many years, it has taken so long before someone finally took time to sit down and work out the correct way of doing it. There is no excuse for anything less than full phase coherence between drivers so that they cross over at -6dB. It just doesn’t get any better. Ever. 4th order roll-off will produce approximately 2nd order electrical slopes, which is enough for power handling.
Next, delay the tweeter to align it with the woofer. A sure-fire way of telling whether the first step has worked is when the delay corresponds exactly to the horizontal distance between the voice coils. After all, the first step removed group delay caused by the natural roll-off.
Finally, the icing on the cake. The sum of an ideal LR4 system is a second order all-pass with a Q of 0.7. In order to avoid the problems associated with correcting phase exactly, build an inverse all-pass filter based on theoretical ideal. This filter will be non-causal so there’s a good reason for using FIR. The step response of this system is precisely what we wanted: no pre-echo, nearly minimum phase.

 

[Littletycoon]

We had the LS1s from the beginning ( they were like everything ) much cheaper back then, Bruno Putzeys first speaker design, I have heard that when Bruno showed his next prototype Eelco and Guido weren’t convinced and Kii was born.
Transparent speakers but never bass monsters.View attachment 452183

Very interesting listening position, I wonder how it sounds

 

[Littletycoon]

I guess the price is simply not competitive anymore (they used to be much cheaper when they came out).
Nevertheless, on HighEnd Munich (few years ago) they blasted me away with a Rammstein demo.
I really can feel with Amir - they have some magic and they can sound like a revelation in terms of naturalness.

Unfortunately to me they don't sound different to gallo strada speakers. But that's probably due to my lack of..........(Still trying to figure this out)

 

[amirm]

Would you pick these over the Salon 2?

You all have a way of putting me on the spot. If I had to have them in the living room, yes. Otherwise, the bass response from the Salon 2 is superior so I would still buy it but would be a tough fight with Genelec 8361a.

 

[amirm]

(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 think the flat top makes the speaker much prettier than if they had the roundover there. So if it was not needed technically, then it was the right call.

 

[beefkabob]

I'd take the Genelec and go 5 speakers for the $$$

 

[PristineSound]

You all have a way of putting me on the spot.

You can always faithfully count on us doing that