GRIMM Audio LS1c & SB1 DSP Speaker Review

[Arindal]

All the red marks are at pronounced edges that will produce diffraction in some band.

I had data from anechoic measurements and can say, things are not as easy. For example the top end of the bridge-baffle is curved in a particular way so the distance between the tweeter and any point of the edge greatly differs over a pretty broad window. This is causing the diffraction to be spread over several frequency bands and interference dips caused by edge diffraction to be cancelling each other out.

The only measurable edge diffraction is indeed caused by the side edges of the bridge, as seen from the tweeter. As the bridge is not extended towards the top end, this effect is not as strong as expected, but creating a certain narrow-banded cancellation dip on axis, around 3.5K. If I recall the concept correctly, it is EQ´ed on axis leading to a very narrow broadening of dispersion pattern in order to correct diffuse field perception. It is not audible as tonal coloration.

Surround/basket of the woofer as well as the edge of the cabinet are basically invisible for any soundwave created by the 3 drivers. The tweeter sound sees an edge as early as it reaches the side edges of the bridge, and midrange as well as woofer are only operating as cardioids or within the range of higher directivity index due to diaphragm size.

And directivity is going up and down too, if one takes the 45° polar as some evidence.

45deg is not a good indicator for directivity. Pretty much anything can happen in this region and you would not be able to predict the rest of the polar behavior. If you do not have a spinorama or d.i. calculation, FR at 70, 110 and 180deg combined tell a much clearer picture.

The cardioid pattern from the mid I only believe if someone shows a spinorama. If a cardioid would be so simple as to put a plank in front of a thick indentation then many things would be simpler.

I have measured the midrange cardioid under side angles and it definitely works as intended (will check if there are measurements publicly available). Note that the cardioid is not created by the bridge itself but by a combination of different, pretty dense foam rings glued onto the midrange´s basket from behind. Obviously some sort of allpass/attenuation flow resistor forming a cardioid pattern from what would naturally be a dipole.

A passive cardioid is that simple, ask @sigbergaudio - It is just not commonly used because it is setting a limit to the max SPL and the lower cutoff frequency of the midrange alike as it might run into an unwanted acoustic short circuit or dipole behavior the lower frequency gets.

 

[kyuu]

This thread is a good example of why I am hesitant to send speakers either to Amir or Erin, because 100 random people who don't really know what they're talking about pop out of the woodworks to analyse the results as if they're acoustical engineers (while they're obviously not).

Not sure I see the harm? Besides, since you're around you can correct anyone who's spouting nonsense.

 

[boXem]

Besides, since you're around you can correct anyone who's spouting nonsense.

Having gone through this, that's unfortunately not always the case.

 

[mcdn]

This thread is a good example of why I am hesitant to send speakers either to Amir or Erin, because 100 random people who don't really know what they're talking about pop out of the woodworks to analyse the results as if they're acoustical engineers (while they're obviously not).

The Grimm is interesting but it was always a bit of a science experiment in wide dispersion and linear phase. I've no doubt it sounds fabulous as I love wide dispersion, but like others I'd prefer some proper bass for the money, and the distortion performance just hasn't kept up with more recent designs at much lower price points.

Even your smallest sub has twice the volume and more than double the displacement of the Grimm one, so you wouldn't get complaints about its output, which really is the thing that has the crowd here triggered.

 

[mcdn]

Having gone through this, that's unfortunately not always the case.

There are always idiots. But you got a golfing panther, a happy panther, and two glowing recommendations from Amir with very positive comments from him and from most posters. Is that not mostly good for you and your business?

 

[Frank Dernie]

These same three drivers put in a conventional box and married to a solid passive crossover design would yield 99% of the audible performance of the Grimm. For a LOT less money!

 

[thewas]

Let's take a look at the terrible frequency response. If you were to look at the scale, you would see that the ripple is +/-1dB in the worst case - I mean the Geithein. This is supposed to be interference at edges, but a plausibility check is not offered; you could calculate the hypothesis and then superimpose it on the data.

I had data from anechoic measurements and can say, things are not as easy.

I have detailed anechoic data from a famous model of them which I unfortunately am not allowed to publish here and they show that there is some significant smoothing on their website data (which isn't really a big issue in my opinion) but also significant directivity issues that cannot be seen well by them publishing only 0 and 45° curves, several large variations in their horizontal radiation from +-30° to +-70° (-6 dB) even in the 500 to 5000 Hz band (vertical is even messier).

I still enjoy listening to them as they clever tuned so that issues are not really annoying but from measurement POV they are far from SOTA.

 

[boXem]

There are always idiots. But you got a golfing panther, a happy panther, and two glowing recommendations from Amir with very positive comments from him and from most posters. Is that not mostly good for you and your business?

What's good for business is visibility, as long as the product is not a complete technical failure. On this specific forum, pricing is an (the most?) important factor to ensure a boost in sales. The awards and positive comments were mainly good for me as a person, since it was a recognition for my work.
I would (and certainly will) do it again, I was simply responding to the idea that participating allows to correct nonsense. As you just wrote, idiots won't change their mind and arguing with them is a lost battle from the beginning.
But we are out of subject, sorry.

 

[Heinrich]

I have detailed anechoic data from a famous model of them which I unfortunately am not allowed to publish here ... from measurement POV they are far from SOTA.

And again, as you write the above in reply to @Arindal, you are most probably referring to a Gaithein speaker, that @olieb meant to diss bevcause of edge re/diffraction. This all meanders a bit.

So, you do *not* mean the LS1, thank you.

I'm with @sigbergaudio - I once for the fun of it, as I thought, published a DIY design experiment and got dissed in an instant. I had no spinorama ;-) And everything else was against good manners and tradition - which cannot be. I asked for it, my bad.

 

[Frank Dernie]

As you just wrote, idiots won't change their mind and arguing with them is a lost battle from the beginning.

This has been my experience too in my area of experience. People who are completely confident but not competant are not swayed by fact and disappointingly common in the internet era.

 

[thewas]

And again, as you write the above in reply to @Arindal, you are most probably referring to a Gaithein speaker, that @olieb meant to diss bevcause of edge re/diffraction. This all meanders a bit.

So, you do *not* mean the LS1, thank you.

Yes, that's why I quoted the part where you wrote "you would see that the ripple is +/-1dB in the worst case - I mean the Geithein".

By the way it is not Geithein or Gaithein but Geithain, like the town where they are made.

Geithain - Wikipedia

en.wikipedia.org

 

[Arindal]

they show that there is some significant smoothing on their website data... but also significant directivity issues that cannot be seen well by them publishing only 0 and 45° curves, several large variations in their horizontal radiation from +-30° to +-70° (-6 dB) even in the 500 to 5000 Hz band (vertical is even messier).

That complies more or less with the data I had. There are angles under which you have a lot of narrow banded FR issues and even some which look like a directivity error. Looking at the broader picture, i.e. the listening window and the averaged SPL under all angles, it looks relatively smooth with the exception of that 3.5K band.

I still enjoy listening to them as they clever tuned so that issues are not really annoying but from measurement POV they are far from SOTA.

If you refer to SOTA as ruler-like FR graphs without any ripples, you are certainly right. I tend to side more with those developers regarding averaged FR over certain windows of angles and frequency bands to being more important, as the narrow-banded imperfections are rather unlikely to really cause tonal errors.

For example, the decreasing directivity index of the Grimm in the lowest band of the tweeter playing alone (2-5K) looks rather subtle on most of graphs, but in an improperly treated room I always find this band to be audibly dominating.

 

[thewas]

There are angles under which you have a lot of narrow banded FR issues and even some which look like a directivity error

They not only look but they are significant and wide directivity errors but like every brand Geihain has its fans which tend to see its results from more pink glasses than from other brands.

If you refer to SOTA as ruler-like FR graphs without any ripples, you are certainly right. I tend to side more with those developers regarding averaged FR over certain windows of angles and frequency bands to being more important, as the narrow-banded imperfections are rather unlikely to really cause tonal errors.

I prefer brands which do both well.

For example, the decreasing directivity index of the Grimm in the lowest band of the tweeter playing alone (2-5K) looks rather subtle on most of graphs, but in an improperly treated room I always find this band to be audibly dominating.

I see the slightly decreasing directivity rather from 1 to 3 kHz and the Geithain has a much larger decrease from 2 to 5 kHz.

 

[staticV3]

Sure, and why not go all the way and make a three-way speaker? The physical space under the speaker is there, as I pointed out in #56.

Something like:


Minus the baffle shape. Keep the GRIMM Audio LS1c shape, which I think is nice and probably also functional.

GGNTKT M3 basically:

 

[Pearljam5000]

For those who can't read measurements
Which one of them is as good or better than LS1C (without the subs)

 

[Sokel]

The funny thing at this thread is that we compare the BOM of the speaker with its price, as if all the hard work to reach such a result is for free

By the same mindset, what is the actual silicon price of a $100 ESS chip? A few cents?
Why no one is complaining about that?

The speaker was designed with certain goals in mind, that's easy to see.
It's also fairly dated so comparisons with newer ones which may very well stepped at its design is unfair.

 

[olieb]

For example the top end of the bridge-baffle is curved in a particular way so the distance between the tweeter and any point of the edge greatly differs over a pretty broad window.

The curve basically follows the woofer radius. And therefore the difference in tweeter edge difference will be smaller than with a straight edge. I do not see a reason to invoke the application of superior wizardry here. That said, this might be a good solution, if the diffraction from the different edges cancel out to a (high) degree.

This is causing the diffraction to be spread over several frequency bands and interference dips caused by edge diffraction to be cancelling each other out.

This will happen only at certain points in space, not everywhere. This shows in the off axis behaviour and that is the reason why the 45° polar is evidence for the directivity behaviour (to some extent).

Surround/basket of the woofer as well as the edge of the cabinet are basically invisible for any soundwave created by the 3 drivers.

Amazing, this seems a special form of sound then, as typical waves "see" all kinds of edges, especially the sharp and big ones. The best way to minimise it is an infinite baffle or as a substitute a big round surface or a super small baffle (but the Geithains are neither).
It is possible to balance the cancellations and other interference in space to some degree, but the diffraction is there. And it is the art of engineering to make the best possible balance.

I have measured the midrange cardioid under side angles and it definitely works as intended (will check if there are measurements publicly available).

There seems to be other data, as @thewas mentioned. But not to the public.
Interestingly enough, Geithain speaks about "cardioid" up to 300 Hz and no mentioning of the mid being cardioid n their page. So it its not even clear what is "intended".
A true cardioid has a beam width -6dB of 90° BTW, so it is a very wide pattern.

That complies more or less with the data I had. There are angles under which you have a lot of narrow banded FR issues and even some which look like a directivity error.

What is in your opinion the cause of such "FR issues" under specific angles? If it is not a result of diffraction, what else is there?

@Heinrich
I did not "diss" the Geithains, that is pure nonsense on your side. I did not hear them, I have not seen much (or independent) measurements and I only commented about the picture: I kind of like the looks and made the remark that this form produces (more) diffraction than the LS1. Astonishing that people want to change physics if someone mentions the slightest spot on their precious.

 

[Purité Audio]

This, we stopped stocking them purely because of the cost/value proposition, Grimm admitted they were targeting the ‘oligarch’ market which isn’t wrong and certainly not today unusual .
Keith

 

[Blockader]

View attachment 453600View attachment 453601
For those who can't read measurements
Which one of them is as good or better than LS1C (without the subs)

LS1C is better for home use. Wide directivity gives better spaciousness, tonal richness and as Sean Olive puts it, wide directivity speakers disappear better in rooms. This is coming from a 8361 owner.

 

[Heinrich]

@Heinrich
I did not "diss" the Geithains, that is pure nonsense on your side. I did not hear them, I have not seen much (or independent) measurements and I only commented about the picture: ...

You did, and more important, how is it related to the LS1, which also shows (in the measurement) ripple at unexpected frquencies:

The FR shows the dips and peaks in all bands (above 2kHz in particular) . And directivity is going up and down too, if one takes the 45° polar as some evidence.
It seems to be exactly the case that Putzeys describes: Edge diffraction (from narrow baffles) that comes about as coloration to a certain degree, only that the Geithain do not have a truly narrow baffle.
The cardioid pattern from the mid I only believe if someone shows a spinorama. If a cardioid would be so simple as to put a plank in front of a thick indentation then many things would be simpler.

This, we stopped stocking them purely because of the cost/value proposition, Grimm admitted they were targeting the ‘oligarch’ market which isn’t wrong and certainly not today unusual .
Keith

Obviouly not all of us are oligarchs.