• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Is the LXmini by Siegfried Linkwitz the answer for home audio?

Shazb0t

Addicted to Fun and Learning
Joined
May 1, 2018
Messages
643
Likes
1,230
Location
NJ
D

Deleted member 2944

Guest
All this shows is that you misunderstand how the Klippel works. It's not clever.
No, that's a straw man.
Rather, it's the interpretation of the results where discussion is appropriate. (I would think that should be obvious by now.)

And all of this assumes that multiple NFS testers would achieve the same objective measurements to begin with.

Dave.
 

maverickronin

Major Contributor
Forum Donor
Joined
Jul 19, 2018
Messages
2,527
Likes
3,308
Location
Midwest, USA
No, that's a straw man.
Rather, it's the interpretation of the results where discussion is appropriate. (I would think that should be obvious by now.)

Readers can do that for themselves...

And all of this assumes that multiple NFS testers would achieve the same objective measurements to begin with.

Probably won't be an issue as long as it's not too cold out...

https://www.audiosciencereview.com/...eumann-kh80-dsp-monitor-measurements-3.14637/
 
OP
A

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,423
Likes
7,940
Location
Brussels, Belgium
ASR can be an odd place sometimes.

For those insisting on a NFS test, what do you think that this test will show that is not already known from SL’s outdoor measurement and significant explanation of the design on his website?

Michael

Siegfried finished these speakers two years before he passed away.

Now i’m not saying that he was in no condition to design a speaker back then, but Incase he missed something subtle but obvious, the measurements can guide owners towards a solution.

It’s like asking why would you sequence the human genome if you could just study the human body physiologically.
 

maverickronin

Major Contributor
Forum Donor
Joined
Jul 19, 2018
Messages
2,527
Likes
3,308
Location
Midwest, USA
For those insisting on a NFS test, what do you think that this test will show that is not already known from SL’s outdoor measurement and significant explanation of the design on his website?

It will certianly add less than measurements of a completely unknown design, but making a database for apples-to-apples comparisons has definite value.

If we're going to use that a a standard Amir might as well skip a lot of other speakers which already have published measurements from somewhere else.
 
D

Deleted member 2944

Guest
I would not have any issue if some other LXmini owner decided to contribute a speaker to Amir for NFS testing. It won't be me though. :)
You can beat me up for my stance on this. I'm totally fine with that.

Dave.
 

NTK

Major Contributor
Forum Donor
Joined
Aug 11, 2019
Messages
2,656
Likes
5,819
Location
US East
Measurement is not the problem. Interpretation of the data is.

In section 10 of Dr. Olive's paper on the preference score model, he discussed its limitation. There isn't a good model to relate the perceived spatial attributes of a speaker with its measurements. Listeners have strong preference to perceived spaciousness, and this is the area where panel and Linkwitz's speakers seem to be good at.

Olive Preference Score Paper.JPG Toole Loudspeakers and Rooms.JPG

References:
https://www.researchgate.net/public...e_Ratings_of_Around-Ear_and_On-Ear_Headphones (Todd Welti linked to the wrong, but in this case, right, paper.)
https://www.academia.edu/27512185/Loudspeakers_and_Rooms_for_Sound_Reproduction_A_Scientific_Review
 

mdsimon2

Major Contributor
Forum Donor
Joined
Oct 20, 2020
Messages
2,477
Likes
3,315
Location
Detroit, MI
Not to get in a pissing match over when some died but it was 4 years not 2.

There is plenty of well reasoned discussion on OPLUG regarding modifications to the design. The trade offs in this design are well understood.

I doubt that the NFS will provide any additional insight but as Dave said if someone wants to build / donate a LXmini for NFS testing I wouldn’t mind the additional data. However, the lack of a NFS test is not going to keep me from enjoying the LXminis, YMMV.

Michael
 

MrPeabody

Addicted to Fun and Learning
Joined
Dec 19, 2020
Messages
657
Likes
942
Location
USA
So just to get it out there, i'm not an expert or anything close to that. so take whatever I say here with a grain of salt, I'm just discussing what I understood from different speaker building/purchasing trends and processing it all together.

This discussion is also for home audio, and i also mean typical everyday person home audio. So the 1% here with giant mansions this discussion doesn't apply to you.

Also, this discussion is also for people who want to share their audio experience with other people. It does not apply to people with audio rooms with one chair in the 'perfect spot', this is a discussion to have a very wide 'perfect spot' (thus the 'home audio' in the title) so more than person can enjoy the 'perfect spot'.

Part 1: Tonal Balance VS Stereo image.

This is the main compromise for people that want to have a wide sweet spot, most people purchase a wide directivity speaker that radiates equally over a wide surface so that tonal balance is maintained for everyone (flat off and on-axis response).

While this is a very interesting proposition, the stereo image suffers dramatically. the moment someone is not sitting at the center between the two speakers, the stereo image instantly collapses towards the speaker you're closer to.

View attachment 108291

While both volumes are somewhat equal, the time it takes for the sound to reach our ears is not the same. sound arrives quicker from the speaker you're closer to. this causes a shift in our perception of the sound and the image collapses to the speaker we're sitting nearest to. The SPL from the pic above represents perceived loudness.

Well how about speakers with narrow directivity (flat on-axis response)? Well this is the other side of the compromise. When you sit off center, the volume from the speakers decrease. and the farther off-axis that you sit, the worse the tonal balance become.

However, just like wide directivity, the sound from the speaker you're sitting closer to arrives before the speaker that you're sitting far away from.

Under optimal conditions, one can trade time of the sound for the intensity of the sound so that the stereo image doesn't collapse to one speaker when someone sits closer to one speaker over the other.

Basically, the center position would be just 15° off axis to both speakers (or whatever the speaker can handle without severely affecting the tonal balance). so a person sitting left center would be on axis to the speaker on the right, and 30° off-axis to the speaker on the left. This way both speakers are perceived as equally loud and center image is maintained.

View attachment 108301

With a narrow directivity speaker, if the path to the further away speaker is the most on-axis path, then center image is maintained for all people sitting equally on the horizontal plane (the sofa).

However, this is all hypothetical and many people find time intensity trading too complicated and not very practical to do in their own room and with their own speakers. Not to mention that tonal balance is not perfectly maintained to people sitting off center.

Part 2: The LXmini by Siegfried Linkwitz, is it the answer for proper stereo image and tonal balance to a wide audience?

The LXmini is a DIY speaker with a very very wide directivity that promises flat on-axis and off-axis response. the LXmini also prevents the sound image from severly collapsing (some collapse ofcourse still happens) to the speaker you're sitting closest to.

View attachment 108308

Briefly, the LXmini uses an upward firing woofer, which is omni-directional. and right above it is a dipole (a bare full range driver) that radiates to the front, and also to the back (in the opposite polarity). the Full range driver is basically an oscillating plate with the baffle removed.

When you cross an omnidirectional driver with a dipole driver, the negative phase of the dipole (radiation behind the fullrange driver) cancels the radiation to the back produced by the omnidirectional driver. The resulting response is a carotid frequency response, which is wider than a dipole, but less wider than an omni.

330px-Cardiod_animation.gif


View attachment 108309

So basically the LXmini is an omnidirectional speaker at the low frequencies, a cardioid at the middle and a dipole at the high-end.

the pole behind the full-range also works to scatter the sound towards the listener at the high (dipole) end.

The result is (Acording to Linkwitz) a very wide dispersion speaker that radiates the entire room (except the wall behind the speakers), and the recipient percieves a stereo image that is not hard bounded by the speakers, the stereo image spreads smoothly between the speakers and extends well beyond the edges of the two speakers. Also the auditory scene is not very crunched to one speaker when you sit off-axis on the horizontal plane.


What are your thoughts on this? Do you agree that the LXmini seems like a good solution to achieve a good stereo image and tonal balance?

I very much enjoyed your write-up and appreciate you for taking the time to do it. It gave me a perspective for the LXmini that I hadn't previously had.

You did a pretty good job at identifying the conflict between good stereo imaging vs. flat frequency response, for multiple listeners in different locations in a typical room. I did not quite follow your reasoning for why the LXmini would be ideally suited for mitigating this conflict. Perhaps it is, but I didn't understand why you were saying that it is. This may be a very complex thing that would require an inordinately complex analysis, to do justice to the question. I'm not sure.

The picture with the three bunnies is interesting. By placing the two speakers very far apart, two speakers with narrow directivity, aimed inward toward the center of the listening area, can resolve the conflict for multiple listening positions. But, and this but is a big but, the distance separating the two speakers has to be great, in comparison to the width of the collective listening area, such that the two distances will be very nearly equal, for all of the listeners, and such that all listeners are situated within the narrow directivity angle of the speakers. Maybe this works in a room that is very wide and short, but then only if the listeners don't object to the exaggerated stereo effect you get with one speaker located way over to one side and the other speaker located way over to the other side. Personally, I would not like this. For me, the resolution to this conflict is to do the opposite: place the two stereo speakers closer together, as close together as need be in order that the two distances will be nearly the same, for all listening positions. Depending on the particulars of the room, this may imply the need for the dispersion to be reasonably good, possibly but not necessarily a little bit better than what is offered by some modern speakers where directivity is increased at the low end of the tweeter range.

When I look at the off-axis response plots of the LXmini, one thing that gives me some concern is the way the high-frequency response becomes unusually erratic when just modestly off axis, i.e., by thirty degrees, and then worsens as you move further off axis. The presumptive explanation for this is that the driver used for the high frequencies is too large. It may have an adequately flat on-axis response, but off axis, the difference in the distance, from the listener to the near edge of the cone vs. the far edge of the cone, is well in excess of the wavelength. As such, it is to be expected that this full-range or mid-range driver would exhibit erratic off-axis response in higher frequencies. If I intended to place this speaker near a side wall, or for anyone to listen to it while located off to one side, I would possibly have some concern about this.

In his original version of this speaker (Pluto), he used a smaller 2" full-range with an inverted metal dome, manufactured by Aura. He seemed very happy with that driver, and it seemed to be a primary motivating factor for him to pursue that design. Here is a quote from his presentation of the Pluto 2.1:

"No changes were made in the tweeter selection. The Aura driver is instrumental to the omni-directional PLUTO concept since this tweeter allows for a low 1 kHz crossover frequency and uniform radiation over large off-axis angles up to several kHz due to its small external dimension. I am not aware of another equally well suited driver for this application."

That's a pretty definitive statement, and certainly does say something about the suitability of the larger driver he used in the LXmini. So why the change to the larger driver? He discussed his reasoning for this change, on the "Design" page for the LXmini:

"PLUTO is essentially omni-directional up to about 3 kHz. At higher frequencies the 2" tweeter becomes ever more forward firing. I postulate that if less of the large reflecting surface behind the speakers is illuminated with sound, then the stereo imaging will also be less affected. Thus to be less placement sensitive a loudspeaker should minimize radiation to the rear and be forward directional."

Perhaps this makes sense, but as I read it, the sense I get is that he is saying that the larger midrange is less directional at frequency than the smaller, which is obviously not correct. To me, this is an example of trying to come up with an ostensible rationale when not wanting to discuss the true rationale. With either of the two full-range drivers, there is a gradual transition from the pattern being dipole due to cancellation at the sides, vs. the pattern being dipole due to the natural directivity of the driver. It isn't apparent to me why it would be critically important where this transition occurs. I think that there is little question that the major difference would be with the smoothness of the treble response, particularly for off-axis locations, but even for on-axis listeners. He also switched to a different woofer, and moved the crossover point lower. I can't help but wonder if the lower crossover point was made necessary by the behavior of the metal cone woofer, and if the lower crossover point is what drove the decision to switch from the 2" Aura driver to the larger full-range used in the LXmini. The true answer will never be known.

I've been a fan of Linkwitz for many years, and have been fascinated by his approach to loudspeaker design. But with the LXmini, my sense is that whatever benefits there may be to the dipole radiation pattern of the full-range driver, those benefits wouldn't likely make up for the uneven treble response, which is evident in the on-axis curve, above about 5 kHz. It is an interesting speaker for sure, and for people who want to dabble in some easy DIY speaker building, it would be a fun project for sure. I haven't looked into it enough to know whether all the stuff you would need to build the Pluto is still available, but if so, I would consider building it rather than the LXmini.
 

phoenixdogfan

Major Contributor
Forum Donor
Joined
Nov 6, 2018
Messages
3,294
Likes
5,070
Location
Nashville
I've given some thought to building these. I already have four channels of amplification and a miniDSP 2x 4 HD, so it would just entail buying the plans from the Linkwitz family and ordering a kit from Madisound. Even if I don't like them as a main system, I'm sure they would be viable as surrounds.
 

phoenixdogfan

Major Contributor
Forum Donor
Joined
Nov 6, 2018
Messages
3,294
Likes
5,070
Location
Nashville
I dont get why people are so scared of measurements?
If it measures "poorly" it wont effect your enjoyment, just more data for everyone.
I am on my 3rd Linkwitz design.....
Sometimes measurements can be a deal breaker. I very much doubt any listeners on this forum will be auditioning any Zu's anytime soon. :p
 

ooheadsoo

Active Member
Forum Donor
Joined
Aug 14, 2020
Messages
198
Likes
163
The fear is not of the measurements, the objection is to the rigid interpretation of Harmon/Toole/Olive, i.e. anything that falls outside of a singular model of directivity is automatically frowned upon.

My pair is not in current use, but my build is much too shoddy to withstand shipping.
 
Last edited:

JeffS7444

Major Contributor
Forum Donor
Joined
Jul 21, 2019
Messages
2,347
Likes
3,507
My "problem" with LX-Mini is that I can't bear to part-out my Linkwitz Plutos! Pluto also have speaker-level inputs which is occasionally handy
 

AudioJester

Addicted to Fun and Learning
Forum Donor
Joined
Jan 7, 2020
Messages
912
Likes
1,211
I have not had the LX-mini for a long time. However, previous in room measurements of my LX521 have been pretty good.

So it is directivity measurements which dont fall into the Olive/Tool range? How should it be measured or interpreted then?
How do Sigfried's measurements differ with his deliberate design choices?
 
OP
A

abdo123

Master Contributor
Forum Donor
Joined
Nov 15, 2020
Messages
7,423
Likes
7,940
Location
Brussels, Belgium
I have not had the LX-mini for a long time. However, previous in room measurements of my LX521 have been pretty good.

So it is directivity measurements which dont fall into the Olive/Tool range? How should it be measured or interpreted then?
How do Sigfried's measurements differ with his deliberate design choices?

I think the LXmini intentionally radiates the room (instead of having a baffle or dampening potential reflections).

So when you cancel the reflections (with anechoic measurments) the directivity might look weird compared to typical speakers with baffles.
 

ooheadsoo

Active Member
Forum Donor
Joined
Aug 14, 2020
Messages
198
Likes
163
Perhaps this makes sense, but as I read it, the sense I get is that he is saying that the larger midrange is less directional at frequency than the smaller, which is obviously not correct. To me, this is an example of trying to come up with an ostensible rationale when not wanting to discuss the true rationale. With either of the two full-range drivers, there is a gradual transition from the pattern being dipole due to cancellation at the sides, vs. the pattern being dipole due to the natural directivity of the driver.
The 2" driver in the Pluto is monopole, not dipole. The 3" full range driver is dipole but the back wave is deliberately disrupted by the mounting mechanism. The crossover between woofer and full range also provides an overlap of cardioid dispersion, which is what provides extra rear wave cancellation below the dipole region. Oh, and the mini's woofer was built, by SEAS, to Linkwitz's spec originally for the Pluto to be crossed at 1khz. You're suggesting that it's good enough for the Pluto but not for the Mini.

@AudioJester Olive/Toole did not do extensive research into non-conventional dispersion, such as dipole and cardioid. It can be inferred that they were not in favor of it.

I would add that the LXmini, if built to plan, is not a design well suited to being shipped. The driver mounting mechanisms are not particularly robust. Some attachment modifications would be helpful to make the assembly/disassembly more modular.
 
Last edited:

ace_xp2

Member
Joined
Apr 5, 2020
Messages
62
Likes
61
As this spectre has been raised again, I'm curious, how do those with this speaker like it when playing decidedly not acoustic music? I'm much more in the home theater realm these days, and have waxed and waned with building a set of these vs. a more typical 5.25"/3"/.75" active three way.

ADD: Maybe amir would be okay with some minor construction upon arrival, say remounting the upper tube/lower stand and full range speaker if they were shipped disassembled?
 

phoenixdogfan

Major Contributor
Forum Donor
Joined
Nov 6, 2018
Messages
3,294
Likes
5,070
Location
Nashville
As this spectre has been raised again, I'm curious, how do those with this speaker like it when playing decidedly not acoustic music? I'm much more in the home theater realm these days, and have waxed and waned with building a set of these vs. a more typical 5.25"/3"/.75" active three way.

ADD: Maybe amir would be okay with some minor construction upon arrival, say remounting the upper tube/lower stand and full range speaker if they were shipped disassembled?
Another big plus of these speakers are that they could probably be disassembled easily and stored and/or moved without any problem. They certainly IMO take up less room than just about any high end design I know of.
 
Top Bottom