GRIMM Audio LS1c & SB1 DSP Speaker Review

[kharan]

Not at all. Blade 2´s directivity index is much higher compared to d.i. in the lower mids, more or less continuously increasing, while Kii´s is pretty constant below 1.5K and a bit alternating above, with a notable hump around 2K which is indicative of lobing issues.

When judging directivity, I recommend not to stare at d.i. graphs, but compare octave-broad bands or a bit broader beginning with the fundamental band which is increasingly localizable (300-800Hz), with different reflection windows separated. It is more helpful when trying to roughly predict reverb tonality.

I prefer when you use numbered frequency bands rather than terms like brilliance or even treble. Every online source points to slightly different frequency bands for each terms. Sometimes large differences too, I've seen treble referred to as frequencies going as low as 2000 Hz.

That aside, if you take the 400-800Hz octave, the DI for the 800-1600 Hz octave, or even the DI on the 1600-3200 Hz octave for the Blade is closer to that of the DI in the fundamental octave (400-800) than on the Kii.

And to be blunt you can't achieve constant DI under 1.5k extending down to the bass region without some cardioid like effect.

It is not necessarily sounding bad under any condition, but experience is telling me that this particular pattern in a typical living-room environment with reflective side-walls, reflective ceiling, rear wall nearby, is producing a tremendously colorated reverb reflection and reverb pattern, very lower midrange-heavy, dull, lame, detached from phantom sources, artificial.

If that's your experience, this is perfectly respectable, but it would take a lot more than personal experience to make a factual claim.

You mean ´evenly colorated´ or ´continuously decreasing in level´? I see no indication why reverb that shows a decreasing level of harmonics from octave-band to octave-band, should be anyhow desirable. I would rather say it is sufficiently colorated to not being recognized as the same tonal pattern as the direct sound, by our brain.

That said, I am personally not a fan of Grimm or Kii either, but I can't imagine them to sound anyhow similar to the Blade, and under disadvantageous conditions they tend to show some kind of brilliance-rich reverb (3-6K elevated) whenever I heard them.

I wouldn't expect either the Grimm or the Kii to sound similar to the Blade either, they measure very differently.

But I do a question. There are design constraints that are practically unavoidable, midrange drivers start beaming at 600-800 Hz, tweeters start way too wide at 2000 Hz unless they are waveguided. So either you have a DI shape that is two plateaus with further narrowing when the tweeter starts beaming itself with a non waveguided tweeter, or you have a constantly narrowing DI with a well integrated waveguide.

For the low mids section, if you want to avoid spreading, you either go very wide, which doesn't seem to be a very well liked design from an aesthetic standpoint, or you go cardioid, I don't think you can manage to control dispersion in this area with a classic design.

So the question is along the lines of what kind of DI would you like to see in a domestic speaker, and how do you see that concept taking shape? If possible at all, a speaker design that fits into most homes rather innocuously, not too large, passive (because the market still seems to not enthusiastic about active designs).

 

[Arindal]

I prefer when you use numbered frequency bands rather than terms like brilliance or even treble. ...

That aside, if you take the 400-800Hz octave, the DI for the 800-1600 Hz octave, or even the DI on the 1600-3200 Hz octave for the Blade is closer to that of the DI in the fundamental octave (400-800) than on the Kii.

Accepted. So take D.I., as well as averaged reflection windows, at 400Hz, and compare it to the 800-2,000Hz band, and the 2,000-5,000Hz band and 5,000--7,500. The relative level of these bands does not only represent reverb tonality, but also contributes to the direction from which reverb is perceived (see theories by Blauert, Zwicker, Fastl). Particularly the rear half-sphere (dubbed rear-wall reflections) and around 90deg (side wall reflection) frequency response pretty accurately represents the tonality of the reverb, which is lacking energy in the region of 6-12dB compared to the fundamental bands, in case of such a slim speaker you have a very pronounced steep step in the rear space due to diffraction between 1K and 3K. That is what I call colorated.

And to be blunt you can't achieve constant DI under 1.5k extending down to the bass region without some cardioid like effect.

You actually can, at least down to the lower midrange bands which our brain is capable of distinguishing between direct and indirect sound (beginning around 300Hz as a rule of thumb). Fairly large midrange horns, midrange line arrays, very big midwoofers, dipoles - there are several ways to do it.

If that's your experience, this is perfectly respectable, but it would take a lot more than personal experience to make a factual claim.

The data proving colorations is in the spinorama, it is factual. We can discuss based on personal experience, to which extend it is critically audible and what it does, but my experience is pretty much matching what is to be predicted from the data and what in studio monitoring is the requirement for a very long time.

There are design constraints that are practically unavoidable, midrange drivers start beaming at 600-800 Hz, tweeters start way too wide at 2000 Hz unless they are waveguided. So either you have a DI shape that is two plateaus with further narrowing when the tweeter starts beaming itself with a non waveguided tweeter, or you have a constantly narrowing DI with a well integrated waveguide.

I would regard both solutions to result in a severely flawed reverb/reflection tonality, maybe not as bad as the Blade, but noticeable. But no-one is saying that a standard 2-way monitor with 2,000Hz crossover frequency, is the only possible loudspeaker concept on this planet. There are midwoofers bigger than a 6.5", for example a 12" or 15", starting to narrow below 300Hz, so exactly what is ideal in terms of directivity (of course requiring lower crossover freq and practically a more refined 3-way concept).

what kind of DI would you like to see in a domestic speaker, and how do you see that concept taking shape?

As living rooms are rather reverberant and listening distances in the mid-field area, a more or less constant d.i. between 5dB and 8dB, without a tendency in either direction, or a bit higher for bigger rooms, seems to be the ideal solution when achieved between 300 and 7,000Hz.

Cardioid for the lower part of this range, is surely the most elegant way to go, and can be for example combined with other techniques, such as horns (GGNTKT), waveguide (D&D) or big woofers (MEG) to achieve constant directivity. There are others way, like line sources, arrays, midrange horns, dipoles. I am personally reserved when it comes to very broad baffles, such as used by Grimm, or planars. As wavelengths differ significantly over such a vast frequency range (300-7,000Hz), combining several techniques in a smart way, seems to be the way to go.

If possible at all, a speaker design that fits into most homes rather innocuously, not too large, passive (because the market still seems to not enthusiastic about active designs).

Such is already available, expect for the ´passive´ prerequisite (I think we can ignore the enthusiasm for passive concepts in a thread about an active solution):

 

[kharan]

Accepted. So take D.I., as well as averaged reflection windows, at 400Hz, and compare it to the 800-2,000Hz band, and the 2,000-5,000Hz band and 5,000--7,500. The relative level of these bands does not only represent reverb tonality, but also contributes to the direction from which reverb is perceived (see theories by Blauert, Zwicker, Fastl). Particularly the rear half-sphere (dubbed rear-wall reflections) and around 90deg (side wall reflection) frequency response pretty accurately represents the tonality of the reverb, which is lacking energy in the region of 6-12dB compared to the fundamental bands, in case of such a slim speaker you have a very pronounced steep step in the rear space due to diffraction between 1K and 3K. That is what I call colorated.

That's questionable, because musical instruments should have different radiation patterns for their fundamentals and their harmonics. In general they should even follow the higher frequencies, narrowing directivity pattern, with some added lobing because instruments are not designed to not lobz.

Now, I'm not saying speakers should follow the directivities of acoustic instruments, but I don't think that harmonics should have the same directivities when reproduced through a speaker system is a given.

You actually can, at least down to the lower midrange bands which our brain is capable of distinguishing between direct and indirect sound (beginning around 300Hz as a rule of thumb). Fairly large midrange horns, midrange line arrays, very big midwoofers, dipoles - there are several ways to do it.

To be frank, those systems mostly exceed what people are ready to have in their homes. Except for dipoles, but those also come with their own issues.

The data proving colorations is in the spinorama, it is factual. We can discuss based on personal experience, to which extend it is critically audible and what it does, but my experience is pretty much matching what is to be predicted from the data and what in studio monitoring is the requirement for a very long time.

We do agree on the data, but that it is heard as colouration is your personal anecdote, I have no reason to not believe that how you heard it, but l have no reason to believe that is a generalized preference.

I would regard both solutions to result in a severely flawed reverb/reflection tonality, maybe not as bad as the Blade, but noticeable. But no-one is saying that a standard 2-way monitor with 2,000Hz crossover frequency, is the only possible loudspeaker concept on this planet. There are midwoofers bigger than a 6.5", for example a 12" or 15", starting to narrow below 300Hz, so exactly what is ideal in terms of directivity (of course requiring lower crossover freq and practically a more refined 3-way concept).

Of course, there are other speaker designs, but something with a 15" midwoofer has necessarily a smaller target market than a tall and relatively thin column. Even a 10" like the SourcePoint V10 column widens at 400 Hz.

As living rooms are rather reverberant and listening distances in the mid-field area, a more or less constant d.i. between 5dB and 8dB, without a tendency in either direction, or a bit higher for bigger rooms, seems to be the ideal solution when achieved between 300 and 7,000Hz.

Cardioid for the lower part of this range, is surely the most elegant way to go, and can be for example combined with other techniques, such as horns (GGNTKT), waveguide (D&D) or big woofers (MEG) to achieve constant directivity. There are others way, like line sources, arrays, midrange horns, dipoles. I am personally reserved when it comes to very broad baffles, such as used by Grimm, or planars. As wavelengths differ significantly over such a vast frequency range (300-7,000Hz), combining several techniques in a smart way, seems to be the way to go.



Such is already available, expect for the ´passive´ prerequisite (I think we can ignore the enthusiasm for passive concepts in a thread about an active solution):

View attachment 514781

I'll give you the GGNTKT, I really like this concept, and I've even commented in the past that it's one of the only speakers that achieves near full range constant directivity while looking like it could fit in a living room.

But like I said, it also uses a wide baffle, it's active, uses active cancellation of rear waves, all of this make it a harder purchase for a lot of audiophiles despite its decent enough looks.

 

[Littletycoon]

What is odd in the picture?

https://www.hoerzone.de/shop/lautsprecher/ggntkt/ggntkt-model-m3-paar.html?srsltid=AfmBOoogbYxVc-BwoY6ZjFhOFGPTWukQ61R-H7WezmanE8UnqE5yztPk

 

[Arindal]

Now, I'm not saying speakers should follow the directivities of acoustic instruments, but I don't think that harmonics should have the same directivities when reproduced through a speaker system is a given.

So, if you think that a loudspeaker´s directivity should not approximate natural instruments´ directivity (which would be a ridiculous prerequisite given the vast variety of the latter, so I certainly agree) and not approximate linear tonality either, which exact directivity behavior would be ideal for loudspeakers in your understanding? And why should this be preferred over a balanced/linear reverb tonality (frequency bands below 300Hz and above 7K aside), based on which psychoacoustic theories or practical experiments?

In general they should even follow the higher frequencies, narrowing directivity pattern, with some added lobing because instruments are not designed to not lobz.

To be frankly honest, I do not understand what you want to express. Should in your view loudspeaker directivity approximate musical instruments´ directivity, in terms of narrowing down and lobing?

If yes, could you please give me a hint how to reproduce a recording like the following in a tonally balanced way including the reverb:

It is medium-sized organ (pretty broad directivity, if not omnidirectional) plus trumpet (very narrow directivity, narrowing down even further with frequency). Am I right in my assumption that your directivity concept cannot be applied to two different instruments at the same time, not to speak of an orchestra?

those systems mostly exceed what people are ready to have in their homes.

These concepts might not be as popular for home use, but I do not see the difference in terms of size and living room integration when it comes to examples like:

(Voicepoint)

(P&G)

but that it is heard as colouration is your personal anecdote, I have no reason to not believe that how you heard it, but l have no reason to believe that is a generalized preference.

It is not a personal anecdote. It is congruent with what in pro audio has been figured out a long time ago, and found its way into reference guidelines for studio control rooms, both in terms of in room frequency response and rigorous RT60 tolerance bands down to 200Hz (in order to avoid midrange-heavy reverb).

And I am sorry, but how would you call a situation in which SPL in the brilliance and treble bands >3K is attenuated 5dB or more compared to the lower midrange fundamentals, other than ´colorated´?

 

[MattHooper]

In case anybody’s interested, here’s a video review that just came out of the Grimm speakers.

Having followed this reviewer for a little while now I have found that he is very articulate in describing the technical details, what it’s like setting up and living with the product, and especially the way he’s able to put “what it sounds like” into words. Which is what I care about. (he has reviewed speaker speakers that I’m familiar with and I found his descriptions bang on to how I perceived the speakers as well).

Basically, he finds the speakers to be, in his experience, fabulous in terms of precision and resolution of the characteristic of different recordings. He preferred them to the Kii Audio Three that he reviewed earlier in his recent series investigating active speakers.

 

[sigbergaudio]

He just did a long and interesting interview with Eelco Grimm as well:

 

[hvbias]

In case anybody’s interested, here’s a video review that just came out of the Grimm speakers.

Having followed this reviewer for a little while now I have found that he is very articulate in describing the technical details, what it’s like setting up and living with the product, and especially the way he’s able to put “what it sounds like” into words. Which is what I care about. (he has reviewed speaker speakers that I’m familiar with and I found his descriptions bang on to how I perceived the speakers as well).

Basically, he finds the speakers to be, in his experience, fabulous in terms of precision and resolution of the characteristic of different recordings. He preferred them to the Kii Audio Three that he reviewed earlier in his recent series investigating active speakers.

I wish he would have went more into the differences with Kii 3 as he had them in the same room (I think he just said they were also excellent or something along those lines). Also being very heavily biased towards electronic music makes it hard to gauge how they'd sound on real acoustic instruments.

 

[sigbergaudio]

I wish he would have went more into the differences with Kii 3 as he had them in the same room (I think he just said they were also excellent or something along those lines). Also being very heavily biased towards electronic music makes it hard to gauge how they'd sound on real acoustic instruments.

There is a conclusion video of shorts coming from his "are active speakers the future" series. There may be a bit more with regards to comparisons or at least talking about differences there.