GRIMM Audio LS1c & SB1 DSP Speaker Review

[Hayabusa]

Who said anything about fulfilling the same "requirements"??
My only premise was using the same three drivers.
You fellas are reading between the lines and getting tangled up in whataboutism.

 

[IngMishael]

Who said anything about fulfilling the same "requirements"??
My only premise was using the same three drivers.
You fellas are reading between the lines and getting tangled up in whataboutism.

That is unfortunately how every thread devolves into for products some people feel strongly about on here. Just becomes a circle of "no, this is it!" and "no, it is this rather."

 

[boXem]

Who said anything about fulfilling the same "requirements"??
My only premise was using the same three drivers.
You fellas are reading between the lines and getting tangled up in whataboutism.

Did not get that the debate was about adding wheels to grandmothers, sorry to be out of subject.

 

[Davey]

That is unfortunately how every thread devolvesinto for products some people feel strongly about on here. Just becomes a circle of "no, this is it!" and "no, it is this rather."

Questioning and second-guessing of speaker designs happens daily on ASR. That's not necessarily a bad thing.
I've read this entire thread. A lot of thoughts on the speaker design itself.......on the testing results......whether Amir was operating it correctly.....alternative configurations......etc, etc. All good discussion.

 

[Pearljam5000]

What advantages does the LS1C has compared to let's say the Geithain
RL901K that costs about half and is 16 inch and is coaxial?
Plus it looks much cooler but that's subjective

 

[YSDR]

What a waste of space under the mid-high box to have such a small (and therefore very inefficient) subwoofer enclosure!
Moreover, placing a woofer that way (vertically moving voice coil) is not the best choice for linearity and long-term reliability.

 

[a4eaudio]

....debate...grandmothers...

I don't think there has been any debate. Straw Men aren't usually accepted as a valid debating tactic.

I'd love to hear valid reasons (in an appropriate thread) related to engineering and physics, that would suggest why one human being could use a dome tweeter, a cone midrange, and cone subwoofer, to design a good looking and high-performing speaker but yet for some reason no other human beings could do the same. Unless the argument was simply about active vs passive, which has some validity but is a boring debate.

 

[olieb]

What advantages does the LS1C has compared to let's say the Geithain
RL901K that costs about half and is 16 inch and is coaxial?
Plus it looks much cooler but that's objective

These things look like walking robots from Dr Who, I like it.
From the looks I would think that the polars in mids and highs are a lot less smooth than less wide than the LS1.
The LS1 is a slick speaker with great engineering but it is much too expensive. The Geithains are no doubt far better value for the effort that goes into them and I would love to see them reviewed by @amirm, but I am afraid it will not happen any time soon.

 

[boXem]

Unless the argument was simply about active vs passive, which has some validity but is a boring debate.

That's at least how I understood it.

What advantages does the LS1C has compared to let's say the Geithain

It can be easily carried anywhere.

What a waste of space under the mid-high box to have such a small (and therefore very inefficient) subwoofer enclosure!

The sub is an add on to a speaker that can be carried anywhere. Electronics are in the feet, if you fill this space, that doesn't work anymore.

 

[Pearljam5000]

That's at least how I understood it.


It can be easily carried anywhere.

The sub is an add on to a speaker that can be carried anywhere. Electronics are in the feet, if you fill this space, that doesn't work anymore.

Why would I need to carry it?

 

[boXem]

Why would I need to carry it?

Ask Grimm, it's part of the requirements described in their paper.

 

[Juhazi]

These things look like walking robots from Dr Who, I like it.
From the looks I would think that the polars in mids and highs are a lot less smooth than with the LS1.
The LS1 is a slick speaker with great engineering but it is much too expensive. The Geithains are no doubt far better value for the effort that goes into them and I would love to see them reviewed by @amirm, but I am afraid it will not happen any time soon.

Looks pretty good to me...

musikelectronic geithain gmbh - RL 901K

 

[gnarly]

Would you spend 2 minutes reading the paper about the speaker, it would become obvious to you that a passive solution could not fulfill the requirements.

I assume you mean the original LS1 'whitepaper'. If so, given that one of the design requirements was to be as close to linear-phase as possible, then of course passive can not meet that requirement.

That said. and switching gears, the paper has always felt to me to be more of a marketing piece, than a technical paper.
i think while it makes very valid points about obvious FIR misuses, it also uses very overblown examples ('trainwrecks') to support their LS1 processing solution.
I question why present such overblown, bad-practice examples, other than for making splash.

Further, the technique in the paper of using an inverse-all pass via FIR to eliminate the phase rotation of a standard LR 24 crossover surely works.
But it is no different than using a linear-phase crossover to begin with, on top of the same IIR filtering needed either way for the drivers. A linear-phase crossover and reasonable driver corrections could of been used in "non-trainwreck" examples. (which would have made a much more valid basis for technical comparison to their electrical filter phase correction solution).

To the extent either one of these techniques doesn't have fully acoustic complementary response through crossover on and off-axis, they both have the same pre-ring potential.
No difference.
The paper makes it sound like the electrical filter linearization is superior, with no pre-ring potential ....(like is often feared with linear-phase crossovers lol.)
That's clever technical marketing, imo.

Pls don't get me wrong...I think the Grimm paper has some excellent and accurate info..
But the way the info is presented, seems to be about inflated techno-selling. Which seems to be central to the marketing and pricing strategy.

 

[olieb]

Looks pretty good to me...

It does, but that is the graph from the manufacturer. These have the tendency to look quite flat and smooth somehow
Here are for comparison 100-10k in the same scale:
- top: on axis and 40° from Amir's measurement of LS1
- middle: Geithain's measurent of on axis and 45° of 901K
- bottom: Grimms measurement of on axis and power response of LS1

The only results I would take away here are
901K does not look bad at all
LS1 is much wider (which I actually meant when wrongly writing "smooth"), though it seems smoother too.
EDIT: And the Geithain will have edge/baffle difractions/reflections, as can be seen in the FR and probably in some of the polars too (maybe more so in those not shown?).

 

[Davey]

@boXem
There was a good bit of discussion regarding the white-paper, speaker, crossover, etc, many years ago when it came out.
One of many threads I can remember:

Understanding Grimm Audio XO

I find their approach is very interesting. http://www.grimmaudio.com/whitepapers/speakers.pdf 1. EQ the drivers beyond operating range to flat 2. Apply the intended crossover, eg. LR4. 3. Apply time delay. So far so good. But what about this 4th step, quote .. Finally, the icing on the...

www.diyaudio.com

The linear-phase crossover implementation wasn't innovative....even back then.
Certainly a linear-phase crossover (of this type) could not be constructed with a passive network. Nor did I suggest it could.

I don't really need suggestions to "spend two minutes reading the paper about the speaker." But thanks anyway.

 

[Arindal]

From the looks I would think that the polars in mids and highs are a lot less smooth than less wide than the LS1.

I would suspect the most measurable differences to be identified at angles around +-60...110deg horizontally where the Grimm shows a surprisingly wide dispersion pattern and the MEG a pretty much attenuated one. At +45 deg you just get a hint of that.

And the Geithain will have edge/baffle difractions/reflections, as can be seen in the FR

In which bands do you see them and where do you expect them to evolve from? If I understood the concept correctly, edge diffractions from the tweeter are used to form the directivity pattern, that is what the funnily shaped baffle plank in front of the woofer is for. Midrange and woofer are both cardioids with baffles narrower than the wavelengths they produce, so edge diffraction should not be much of an issue. Same with Grimm thanks to the rounded baffle.

 

[levimax]

One thing I missed over the decades in this hobby is the reason why most speakers changed from "Wide Monkey Coffin Style" to "Narrow Tower Style"? Was it all just aesthetics or was there a technical reason?

 

[olieb]

In which bands do you see them and where do you expect them to evolve from?

I would have thought this to be more than obvious. All the red marks are at pronounced edges that will produce diffraction in some band. Even if it might shape the directivity in some frequencies I doubt this can be done in all.

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.

 

[Heinrich]

... other than for making splash. ... inflated techno-selling. Which seems to be central to the marketing and pricing strategy.

...the Geithain will have edge/baffle difractions/reflections, as can be seen in the FR and probably in some of the polars too (maybe more so in those not shown?).

I would suspect the most measurable differences to be identified at angles around +-60...110deg horizontally ...

Well, here we have a case where we, as tinkerers without any formal training in the subject in question, have to explain to a university professor in the same subject what nonsense he is making. You can do it, but you can also leave it alone. Otherwise we like to refer to authorities and put their statements through the blender. No judgement, that's everyday human behaviour.

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.

But we also have - if the whole thing is correct - very bad interferences at the LS1. If you apply the method of at least asking for plausibility, you find that no, it is not given.

In any case, the measurements by steophile show none of this. I'm not going to start looking for the origin of the ripple in the NFS measurement method again. That would just be very tiring. I just want to say that steam talk doesn't do the speaker justice. For heaven's sake, many people like the LS1! It makes them happy. Have a nice day, and: bonne chance!

One thing I missed over the decades in this hobby is the reason why most speakers changed from "Wide Monkey Coffin Style" to "Narrow Tower Style"? Was it all just aesthetics or was there a technical reason?

Sure, the LS1's design is slightly retro. ( See 1958's Braun LS2 (sic!): http://www.braun-hifi-forum.de/userpix/10_l02_1.jpg )
I think the shift took place once smaller drivers became sufficiently capable and cheap, while the customers appreciated a small footprint.

 

[sigbergaudio]

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).