GRIMM Audio LS1c & SB1 DSP Speaker Review

[Mart68]

Very expensive beer?

We have that in UK and almost all our speaker companies went broke and got bought by the Chinese.

 

[Heinrich]

That has always been the Meyer modus operandi: a superficial appeal to engineering and evidence that falls apart with scrutiny. Ditto ATC, Harbeth.

I'm pretty much sure that the feedback is analog, because at least the woofer is analog. To say "from attosecond to attosecond" is just saying, not to be taken literally. It's legal in common conversation.

 

[gnarly]

I will call BS on Meyer Sound on this one. Feedback output microsecond by microsecond? That means the control system sampling rate is in the order of 1 MHz.

Lol...I never have a problem with calling any manufacturer's marketing claim BS !!!! Same goes for half the "engineering specs" that are all so often marketing inspired.

Heinrich may be right though about the servo maybe being analog, no clue. Afaict, Meyer's self-powered speakers are still all analog.

 

[TNT]

I wonder why they went for the north vertical diffraction additions?

//

 

[tifune]

One of the most tiresome trends on ASR right now is perhaps, ironically, this rise of technically-proficient yet pedantic, dogmatic and nihilistic users that tend towards an overly stringent definition of technical merit than evidence supports.

I vote "I asked chatGPT..." posts as a very close second.

Why is Finland making so many good speakers?

I asked ChatGPT:

"Finland is anechoic down to 20Hz so designers can quickly and easily hear aberrations without specialized equipment"

 

[TNT]

I didn't know that Finland was anechoic - well, I don't here much from them so maybe it's true,,,,

//

 

[Hidde]

I will call BS on Meyer Sound on this one. Feedback output microsecond by microsecond? That means the control system sampling rate is in the order of 1 MHz.

This is from the lecture notes of the Feedback Control Systems class at MIT OCW 16.30 (lecture 20). When the sampling (update) rate of the digital control system is 15× the required system bandwidth, the impact of processing delay on performance becomes insignificant. That means, if the servo sub works to 200 Hz, a sampling rate of 3000 Hz is all it needs.

Feedback Control Systems | Aeronautics and Astronautics | MIT OpenCourseWare

This course will teach fundamentals of control design and analysis using state-space methods. This includes both the practical and theoretical aspects of the topic. By the end of the course, you should be able to design controllers using state-space methods and evaluate whether these controllers...

ocw.mit.edu

View attachment 455325

While you highlight the pain points well, there are some more remarks.
Sampling essentially adds a delay of about Ts/2 yeah. The 15 times sampling is a rule of thumb for which it becomes feasible to build controllers, however higher sampling reduces the sampling latency and can thus improve control performance (can respond faster and thus achieve higher bandwidth/higher stability margin/higher gain.

Increasing sampling rate comes at a price though. As Fs increases the bandwidth that we actually use becomes smaller relative to the Fs. As a result we need more filter coefficients to filter at our desired frequencies and we have less time to do so! --> increased hardware cost.

Furthermore it assumes that the sampling latency is the dominant latency. Latency introduced in reconstruction filters of sigma-delta converters is not neglegible. Latency introduced by interfaces between ADC-DSP-DAC is not neglegible. To give some context, I believe the ADAU1777 is used in the SB1-dmf, it has a latency of 5us analog-to-analog (which is INCREDIBLY LOW, I have yet to find performance close to it).

 

[Esprit]

If the NFS can measure the M9
I trust it completely lol

Amir's next shed…

 

[Low325]

My first post and registered just to say thanks to Amir for the test of the LS1 and to everyone contributing to the thread - I learned a lot. Like many, I’ve always wanted to see beyond the manufacturer’s published data - Grimm has put out a decent amount of data and they are always consistent with their marketing. I landed on the LS1be/SB1 for my home listening enjoyment (a fool and his money ), and so far they’ve been great. No objective data to share…yet. But I trusted the process (toe-in, time delay, positioning after positioning) and found a pleasant listening experience surpassing what I achieved with previous setups - all personal attributes, and I think they look cool and have high WAF.

 

[sigbergaudio]

My first post and registered just to say thanks to Amir for the test of the LS1 and to everyone contributing to the thread - I learned a lot. Like many, I’ve always wanted to see beyond the manufacturer’s published data - Grimm has put out a decent amount of data and they are always consistent with their marketing. I landed on the LS1be/SB1 for my home listening enjoyment (a fool and his money ), and so far they’ve been great. No objective data to share…yet. But I trusted the process (toe-in, time delay, positioning after positioning) and found a pleasant listening experience surpassing what I achieved with previous setups - all personal attributes, and I think they look cool and have high WAF.

Despite a lot of differing opinions in this thread, I think you can rest assured that you have a pretty good setup with the Grimm!

 

[MattHooper]

My first post and registered just to say thanks to Amir for the test of the LS1 and to everyone contributing to the thread - I learned a lot. Like many, I’ve always wanted to see beyond the manufacturer’s published data - Grimm has put out a decent amount of data and they are always consistent with their marketing. I landed on the LS1be/SB1 for my home listening enjoyment (a fool and his money ), and so far they’ve been great. No objective data to share…yet. But I trusted the process (toe-in, time delay, positioning after positioning) and found a pleasant listening experience surpassing what I achieved with previous setups - all personal attributes, and I think they look cool and have high WAF.

Lucky you! I’m sure I’m not the only one who envies the fact you own the speakers!

 

[Low325]

Despite a lot of differing opinions in this thread, I think you can rest assured that you have a pretty good setup with the Grimm!

Thanks! The opinions that were shared that drew attention from the datapoints were very much real (at least in my room) in terms of bass output/reach were the challenges I experienced here in my home. But after working to address them as best I can, to me, it is a sound that is more presenting, instant and where things are not overly emphasized.

Some room issues to deal with but will be enhancing sonics with further acoustical treatments that I can move in and out. Hoping to satisfy my curiosity with some amateur measurements once I obtain a digital interface that I can properly use. Hope to share these if I can get around to it.

Oh yeah and I ordered some longer cables to try to reposition the SB1 around the room too. Fun times ahead.

Lucky you! I’m sure I’m not the only one who envies the fact you own the speakers!

The LS1 were kind of tricky to finally demo (amongst the other good ones; kii, dutch&dutch, ggntkt) not so much in the way that they are bespoke or exotic-unobtainium passives - they are far from that…they’re in the field and was hoping to avoid visiting a recording studio which obviously does not emulate a domestic space let alone intimidating. Though funny enough, this setup would be more at home in a studio. I also wanted to see how it could be conveniently controlled (MU1) and what limitations/enablements were designed with it so waiting patiently to do so was a long time to endure. But thanks!

 

[youngho]

There is an interesting Stereophile review with Eelco Grimm: https://www.stereophile.com/content/grimm-truth-eelco-grimm-grimm-audio-page-2

 

[Duke]

There is an interesting Stereophile review with Eelco Grimm: https://www.stereophile.com/content/grimm-truth-eelco-grimm-grimm-audio-page-2

I found Eelco Grimm's explanation for why 40 degrees of toe-in worked well with his wide-body speakers to be quite educational.

Briefly, by pushing the baffle step much lower, the wide-body format enables reduced sidewall interaction down to a considerably lower frequency than would be the case with a narrow-faced speaker.

Thanks for the link!

 

[Arindal]

by pushing the baffle step much lower, the wide-body format enables reduced sidewall interaction down to a considerably lower frequency than would be the case with a narrow-faced speaker.

My understanding of his comment would be that the wide and rounded baffle rather pushes the baffle step to a lower frequency than a slim baffle. I agree with him that a coherent tonal balance of early reflections is advantageous for imaging and localization, but the baffle shape is rather a measure to keep this constant over the localizable frequency bands, i.e. retaining a wide and at the same time constant directivity pattern above 250Hz (measurements are suggesting it is a bit higher in reality but still well below 500Hz)

The problem, though, is the wide pattern. At 60deg horizontally from speaker axis, the effective sound pressure level is hardly attenuated, so a traditional toe-in of 30deg, with side walls in fair proximity, would result in tonally balanced but pretty strong early reflections. Under studio conditions this might mean additional absorption or diffusion. To effectively suppress these reflections under more lively conditions like at home, you need to toe-in even more to a point the side wall reflection area is ´not seeing´ the +-90deg horizontal window of the speaker.

 

[MattHooper]

I found Eelco Grimm's explanation for why 40 degrees of toe-in worked well with his wide-body speakers to be quite educational.

Briefly, by pushing the baffle step much lower, the wide-body format enables reduced sidewall interaction down to a considerably lower frequency than would be the case with a narrow-faced speaker.

Thanks for the link!

YES!

That part for me was the most eye-opening.
I’m going to quote it here:

—————————————

van Bakel: I'm beginning to see your point about toe-in. Drive it home for me.


Grimm: Sure. So if you toe in a standard narrow loudspeaker, the frequencies above 650Hz will be directed away from the nearby sidewall due to the effect described above. But all energy below 650Hz will still find its way to that wall. Because these mid frequencies have a strong impact on the stereo picture, you will get a blurrier image in the mid frequencies and a more focused image in the higher frequencies. The result is a lack of stereo definition. The highs become narrow, but they sound separated from the rest of the frequency band. To counteract this problem, many audiophiles place their narrow-baffle loudspeakers parallel with the walls. That way, the reflection receives about the same frequency balance as the direct sound. This is a good decision, though it comes at a price, because now the full frequency band suffers from a reflection that impacts the stereo image. But at least the sound is spectrally coherent.

————————————-

That made so much sense to me and described exactly what I have perceived for years of using generally narrow baffle speakers in my room!

His description of how the higher frequencies take on a certain character - more prominent, more focussed, but sort of detached from the body of the sound - is something I’ve often perceived when I’ve tried to use more toe-in.
(and it’s not only my own speakers. It’s what I’ve heard over and over in other rooms with other narrow baffle speakers, stores, etc., when more extreme toe-in is used).

So I’ve always favoured my speakers either facing forward or with fairly modest toe in (depending on my seating distance).

 

[Juhazi]

The difference between narrow and wide box (Grimm, SF Stradivari and monkey coffins) is not huge, but relevant.

"Baffle step" happens when sound waves don't smoothly bend around the baffle, radiation pattern shifts gradually from omni- to monopolar, causing axial spl to rise towards higher frequencies. Respectively off-axis spl ("energy") is reduced towards highs.

Polar map example

 

[Neadych]

Isn't this just a two-band with a near-field subwoofer, like Genelec 8350 and 2 pcs 7370?
What is their maximum direct sound distance in the mid-high range?
Wouldn't it be preferable to have a Neumann 420 midfield or similar Genelec from 3 m.

 

[totti1965]

Isn't this just a two-band with a near-field subwoofer, like Genelec 8350 and 2 pcs 7370?
What is their maximum direct sound distance in the mid-high range?
Wouldn't it be preferable to have a Neumann 420 midfield or similar Genelec from 3 m.

…. or a Geithain RL 921K or a Geithain RL 901K!

 

[Neadych]

The woofer distortion appears worse than the Neumann 150, although it is already cut off for the subwoofer.