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The REAL Problem of March Audio's Sointuva WG (Review, Measurements and Reinforcements with Klippel device)

OP
Nuyes

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So still no particular info on the tightening sequence/torque spec for the driver mounting? So many areas where the thread needs some cleanup/focusing overall, tho.
I apologize for the lack of timeline and precise content organization of the content of the thread.

Because of the sheer volume to be published in the post, and the lengthy our journey to analysis and repair by Sointuva WG.

Apart from that, let's talk about bolts.

Alan's claims about the bolt are 'completely' wrong.

1.Alan argued that distortion could be improved or increased by bolt torque.

2. He also responded to the owner's inquiry about leaking binding posts, saying, "Take it apart and seal it yourself." answered.

3. If the torque value recommended by the manufacturer is standardized and this is the manufacturer's know-how, he must disclose it to the customer exactly.


But that's impossible.
Totally wrong.


1.Because the insert nut structure of this speaker is mostly made of rubber, and the metal is about 3mm (0.11inch) at the end.

The bolt that goes into the insert nut rotates a few turns at the beginning and meets the metal parts, then the more tightened, the more the rubber is compressed and the speaker unit is fixed.

Alan, can you really provide an exact manufacturer recommendation for this (torque)?
If the manufacturer's recommended torque values actually exist, you are obligated to provide the exact torque values while demanding the seal to the customer.



2. Let's talk on the premise that there is a manufacturer's recommended value (if Alan's argument is correct).

If so, at least the fastening strength of each bolt should have been the same or similar.
 

MAB

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With respect, that is no different to the classic response from service agents "Oh this is the first problem we've ever had with X product. (yes, it's a standard BS line)"

The absolute vast majority of people who buy HiFi don't have the means, the knowledge, or the interest in measuring their gear. And neither should they. They base their decisions and place their trust in the manufacturer's statements and specifications.

Where products do not live up to their hype/specs and people have paid a ton of money for them, the situation deserves to be called out. Amir is way to kind IMO with a lot of gear where it clearly doesn't measure up, but he's likely got bigger/more fish to fry.

This Sointuva is not a disaster, but there are clearly facets of the product which don't live up to what was promised. I can see why the binding post issue occurred. Alan would have standard test bananas and would test every speaker. His plugs happened to be solid- he likely never used a hollow 4mm plug or a spade, so the problem with air pouring out was never discovered.

Danny at GR Research would have approved, because they are actually:
View attachment 215443

The rest of it, leaky tweeter-waveguide and resonance issues are probably only obvious due to the very low THD of the entire speaker. In a normal speaker, they would be swamped with other non-linearities. He made a speaker so clean, it highlighted stuff you'd never know about.

But, as usual, it was the dismissive, ducking and weaving and accusations of reviewer incompetence by March, that only served to make it worse. The doubling down, instead of stepping back and acknowledging someone's valid observations and points.
Well stated John.
You have pointed out that lots of big-name high-priced speakers have flaws similar or worse that this. Many of us have bought gear to find things like this from all sorts of manufacturers who should know better. I would have thought March would have understood these basics and bested them. Especially since it seems his target market includes ASR and similar forums, with similar inquisitive skills and criteria. Each one of these is such a small revision to address. And each is a bit of a face-palm since they indicate that no matter how much care has been put into these, they just aren't getting QC'ed in a meaningful way. Really looks like another 15 minutes of proper quality checklist, some solid core binding posts, a couple wire ties for crying out loud, and a recitation of righty-tighty while installing drivers would fix everything. These would be awesome I bet.

On another note... I do wonder how long the tweeters will last. I heard they were crossed over really low.
 

098765

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I apologize for the lack of timeline and precise content organization of the content of the thread.

Because of the sheer volume to be published in the post, and the lengthy our journey to analysis and repair by Sointuva WG.

Apart from that, let's talk about bolts.

Alan's claims about the bolt are 'completely' wrong.

1.Alan argued that distortion could be improved or increased by bolt torque.

2. He also responded to the owner's inquiry about leaking binding posts, saying, "Take it apart and seal it yourself." answered.

3. If the torque value recommended by the manufacturer is standardized and this is the manufacturer's know-how, he must disclose it to the customer exactly.


But that's impossible.
Totally wrong.


1.Because the insert nut structure of this speaker is mostly made of rubber, and the metal is about 3mm (0.11inch) at the end.

The bolt that goes into the insert nut rotates a few turns at the beginning and meets the metal parts, then the more tightened, the more the rubber is compressed and the speaker unit is fixed.

Alan, can you really provide an exact manufacturer recommendation for this (torque)?
If the manufacturer's recommended torque values actually exist, you are obligated to provide the exact torque values while demanding the seal to the customer.



2. Let's talk on the premise that there is a manufacturer's recommended value (if Alan's argument is correct).

If so, at least the fastening strength of each bolt should have been the same or similar.
I can not agree with you more Alan has no evidence to his claim also as he is a maker and president of manufacturer, he should take responsibility of suggesting the data and support to the consumer when problems happen but it hasn't been done....
 

restorer-john

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Alan's claims about the bolt are 'completely' wrong.

1.Alan argued that distortion could be improved or increased by bolt torque.

With respect, you need to be a little careful on this claim.

Loudspeaker driver to cabinet interfaces have been well known for many decades to be an area where significant issues can arise. The bolts, the way they are secured, torqued and seated all can and do make a difference and/or cause issues. I've lost count of the number of speakers I've worked on, where too much or too little torque can cause resonances in the drivers themselves. Very tight tolerance voice coil gaps can even be affected by incorrect or poorly tightened screws very subtly distorting the basket alignment.

If you've never had to deal with a resonance coming from inside a loudspeaker only to find it is the magnet/basket interface or a frame/cabinet vibration, then you haven't tested enough speakers.

Alan does have significant expertise in industrial engineering where extremely fine tolerances and vibration/resonances are analysed to minute levels. Whether or not that applies to his loudspeaker, that's another story. But I do think the purpose of this thread has been achieved and there is little to be gained by continuing to twist the knife on someone who cannot reply.
 

thin bLue

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Alan's new responses

Screenshot_20220629-162213_Gmail.png


This posting is based on request of Alan himself and Nyuse's request. article was first posted to the Korean community, and Nuyes also suggested "to post this to ASR to allow Alan to have a minimal defense".


-------------

I hope we can come up with a solution as a result of the essential mechanical and physical problem analysis, not personal mental analysis of each other.

Let's Keep testing and mkae more theoretical proposals and verifications.
 

YSC

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I hope we can come up with a solution as a result of the essential mechanical and physical problem analysis, not personal mental analysis of each other.

Let's Keep testing and mkae more theoretical proposals and verifications.
I do think this is on Alan's side, actually most of the potential customers couldn't care less about who can measure or mod/fix this speaker, but hope March can make the connector sealing and/or driver mounting/whatever causing all those leaks in the problematic sample in this post, I personally believe the screws/sealing could be a side effect of dilvery damage, you know how the deliver guys usually do to these heavy boxes;)

but if the manufacturer can double think/improve the mounting/ sealing process it's a win win for both his reputation and customer, I know the feeling when you waited for weeks/months to see the anticipated great speaker arrive, only to see 1 or even both of it was loosened/damaged and need to deal with warranty, worse still is when clearly one speaker is performing better than the other and the manufacturer is on a defensive mannar so you have to go extra just to get it fixed
 

Sokel

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The thing that I understand so far and worries me as purifi drivers are very popular is that apart from the minor flaws the distortion at 380Hz is not yet a solved matter.
So,is it an inherent flaw of the driver or of the speaker?Does anyone knows for sure?
 

Heesung

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The thing that I understand so far and worries me as purifi drivers are very popular is that apart from the minor flaws the distortion at 380Hz is not yet a solved matter.
So,is it an inherent flaw of the driver or of the speaker?Does anyone knows for sure?
In fact, OP is testing just that at this very moment. He is soon to reveal the results. Just wait and see.
 
OP
Nuyes

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Finally, something nice has arrived.

@SDC , thank you very much.

The Purifi X series driver has a 3rd harmonic distortion peak of 380hz, and unlike the nonlinear distortion of general motors, it has a property that it does not rise in proportion to the output.

And based on this, Alan makes the following excuses for the harmonic distortion of the Sointuva WG I reviewed.

"It was caused by the reviewer's arbitrarily overtightening the bolts."

I explain to you again.

I have measured and reviewed many speakers so far.
(About 80 or more.)

But I've never disassembled anyone else's speakers except for the Sointuva WG.

Do I look rude and crazy?

Or, do I look like a philanthropist who repairs everyone's speakers for free?


Until the first week of May 2022, the Sointuva WG was just 'one review speaker' to me.

However, something was noticed (THD) by members who subscribed to my review, and the owner of this speakers immediately reported it to Alan.

But Alan blamed the reviewer from the start.

Still, I persevered.

Because I understand that I'm in an unknown country in Asia, it is difficult to trust the data measured by anonymous reviewers...


'At least' "If there is a deviation when measured under the same conditions under the same conditions, wouldn't you be able to trust us?"

So I asked for Sample B, and the owner was happy to send me the rest of the speakers.

But again, Alan's attitude didn't change despite showing Sample A/B comparison results.


We all know.
A simple solution to this problem.

Alan should have been customer-friendly from the start.

Even if the reviewers don't believe it, the equipment and data should be.

But now I know that all these words are useless.


It's simple.
Let's prove it.






01.jpeg



These are 12 mm (0.47 inch) solid aluminum baffles, each precision cut by CNC.


02.jpeg
03.jpeg




I used 75g/m2 density paper, as squeezing the baffle and unit as-is and the paint on the front of the unit could peel off.


04.jpeg
05.jpeg





It compresses very strongly.

The wooden block you see over there is a 'speaker stand' that I made myself for Arendal's 1961 Tower speaker.

So it's quite heavy, thanks to the internal bulkhead with multiple layers of bracing.


Also, I was afraid that there would be various criticisms of the experimental environment, so I tightened the clamps as hard as I could.



06.jpeg




This is the first measurement point.

Nearfield measurement of the unit diaphragm.



07.png
08.png















09.jpeg


This is the second measurement point.

between the magnet and the frame.




10.png
11.png



I still don't see 'something' at 380hz.



So, again, I'll try to find out what voltage the problem is at.



12.png
13.png




Diaphragm nearfield measurement.

Second harmonic distortion is perfectly normal.

However, you can see that the 3rd harmonic distortion suddenly decreases around 2.83V.

I wondered if this had something to do with the resonance Purifi was talking about.


Next.


14.png
15.png




between the magnet and the frame.


15.png




bingo!

At the junction of magnet and frame
Third harmonic distortion shows strange symptoms.


16.png




It rises proportionally up to a certain voltage and then peaks.

That's 3.65V.


I resumed the measurement with 3.65V.



17.png
18.png





Diaphragm nearfield measurement.



19.png
20.png





between the magnet and the frame.




1. When measuring THD for each voltage of 380hz using the DIS module, an abnormality of the 3rd harmonic distortion was found between the magnet and the frame.
This backs up the facts about the Purifi driver.

2.This shows the 3rd harmonic distortion peaks, but I couldn't find the 2nd harmonic distortion peaks near 380hz anywhere on the diaphragm or frame.

3. When measuring between the frame and the magnet, a peak of 3rd harmonic distortion was found at about 450hz (3.65V), but this is about -59dB at the maximum.


4. Distortion, which was the core of the problem raised in the thread's original post, is centered around 400hz, and the second harmonic distortion takes the peak first.


Back to the point,

To some of the issues presented by reviewers and customers, Alan replied, "This is clearly a driver-specific characteristic of Purifi and is found in all Purifi speakers."

Is that true?
 

Sokel

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Seems that the Purifi is not so pure,is it?How can that be,specially if is known matter to the company?
And if there is a solution should that be written in the product PDF?
Strange things...
 

Thomas_A

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Accelerometer measurements of the loudspeaker cabinet walls, have that been done? I’ve had speakers with audible distortion corresponding to peak vibrations of the cabinet. Sandwich construction with 9+9 mm MDF and special damping glue solved it.
 
OP
Nuyes

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The reason I have no choice but to keep using this thread is:

1.Alan tells speaker owners that it's all the reviewer's responsibility.
- no. I have never disassembled a speaker until I got approval from the speaker owner.
This is the manufacturer's responsibility as the problem appeared even when the speaker was not disassembled.

2.Alan slandered me not only to the speaker owner, but also to other prospective buyers. (This is obviously true.)



I think...
As a reviewer, it's okay for me to be insulted and slandered.
Because I have to take responsibility for my actions.
Even if it's not a 'problem'.
Anyone can swear at me, and I'm fine.

But Alan is blaming the reviewers for everything other than the obvious problems (the leaking in the binding post).

In other words, their products are still taken to mean 'perfect'.


Alan, I know you are reading this post.
Live an honest life with no shame.
Don't deceive your customers.

I know you are an aeronautical engineer, and I respect that knowledge and experience.

And Spinorama data from Sointuva WG was enough to excite me and everyone else.

Why are you trying to ruin everything yourself?

It could be a problem with the shipping process.
Or it could be something else we haven't imagined.

And failing to uncover it doesn't prove your incompetence.
Because most people, including myself, know the Sointuva WG is a superior speaker in almost every characteristic.

You should have been kind to the owner and me from the start.
 

098765

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Finally, something nice has arrived.

@SDC , thank you very much.

The Purifi X series driver has a 3rd harmonic distortion peak of 380hz, and unlike the nonlinear distortion of general motors, it has a property that it does not rise in proportion to the output.

And based on this, Alan makes the following excuses for the harmonic distortion of the Sointuva WG I reviewed.

"It was caused by the reviewer's arbitrarily overtightening the bolts."

I explain to you again.

I have measured and reviewed many speakers so far.
(About 80 or more.)

But I've never disassembled anyone else's speakers except for the Sointuva WG.

Do I look rude and crazy?

Or, do I look like a philanthropist who repairs everyone's speakers for free?


Until the first week of May 2022, the Sointuva WG was just 'one review speaker' to me.

However, something was noticed (THD) by members who subscribed to my review, and the owner of this speakers immediately reported it to Alan.

But Alan blamed the reviewer from the start.

Still, I persevered.

Because I understand that I'm in an unknown country in Asia, it is difficult to trust the data measured by anonymous reviewers...


'At least' "If there is a deviation when measured under the same conditions under the same conditions, wouldn't you be able to trust us?"

So I asked for Sample B, and the owner was happy to send me the rest of the speakers.

But again, Alan's attitude didn't change despite showing Sample A/B comparison results.


We all know.
A simple solution to this problem.

Alan should have been customer-friendly from the start.

Even if the reviewers don't believe it, the equipment and data should be.

But now I know that all these words are useless.


It's simple.
Let's prove it.






View attachment 215482


These are 12 mm (0.47 inch) solid aluminum baffles, each precision cut by CNC.


View attachment 215483View attachment 215484



I used 75g/m2 density paper, as squeezing the baffle and unit as-is and the paint on the front of the unit could peel off.


View attachment 215485View attachment 215486




It compresses very strongly.

The wooden block you see over there is a 'speaker stand' that I made myself for Arendal's 1961 Tower speaker.

So it's quite heavy, thanks to the internal bulkhead with multiple layers of bracing.


Also, I was afraid that there would be various criticisms of the experimental environment, so I tightened the clamps as hard as I could.



View attachment 215487



This is the first measurement point.

Nearfield measurement of the unit diaphragm.



View attachment 215488View attachment 215489














View attachment 215490

This is the second measurement point.

between the magnet and the frame.




View attachment 215491View attachment 215492


I still don't see 'something' at 380hz.



So, again, I'll try to find out what voltage the problem is at.



View attachment 215493View attachment 215494



Diaphragm nearfield measurement.

Second harmonic distortion is perfectly normal.

However, you can see that the 3rd harmonic distortion suddenly decreases around 2.83V.

I wondered if this had something to do with the resonance Purifi was talking about.


Next.


View attachment 215495View attachment 215496



between the magnet and the frame.


View attachment 215496



bingo!

At the junction of magnet and frame
Third harmonic distortion shows strange symptoms.


View attachment 215497



It rises proportionally up to a certain voltage and then peaks.

That's 3.65V.


I resumed the measurement with 3.65V.



View attachment 215498View attachment 215499




Diaphragm nearfield measurement.



View attachment 215500View attachment 215501




between the magnet and the frame.




1. When measuring THD for each voltage of 380hz using the DIS module, an abnormality of the 3rd harmonic distortion was found between the magnet and the frame.
This backs up the facts about the Purifi driver.

2.This shows the 3rd harmonic distortion peaks, but I couldn't find the 2nd harmonic distortion peaks near 380hz anywhere on the diaphragm or frame.

3. When measuring between the frame and the magnet, a peak of 3rd harmonic distortion was found at about 450hz (3.65V), but this is about -59dB at the maximum.


4. Distortion, which was the core of the problem raised in the thread's original post, is centered around 400hz, and the second harmonic distortion takes the peak first.


Back to the point,

To some of the issues presented by reviewers and customers, Alan replied, "This is clearly a driver-specific characteristic of Purifi and is found in all Purifi speakers."

Is that true?
Nice measurements! Hope this will bring us closer to the solution.
 

Sokel

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Dear @Nuyes

Your country is amongst the ones with the most kind and respectful people,that was my experience when I visited.
Honesty and pride are very important to you and your people so I can understand your frustration.
And not only me I hope.
The only thing I want to tell you is to keep doing whatever you're doing with the same honesty and passion.
 

YSC

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Im afraid not, the experiment is incorrect. @Nuyes does not have knowledge of vibration measurement.
Maybe not really solving the problem, from my layman eyes the only thing I was disappointed is that the otherwise great speaker designer said there wasn't any issue, while one of the problematic speaker measured by OP exhibit the same thing to a more severe degree
 
OP
Nuyes

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Im afraid not, the experiment is incorrect. @Nuyes does not have knowledge of vibration measurement.
You are right.
I have no knowledge of vibration measurement.

However, the magnet-magnet HD in the Purifi driver, as claimed by Alan, has also been proven with microphone measurements in other reviews.

And Alan explains that it increases as it is firmly anchored to the cabinet, causing the distortion problem for the Sointuva WG presented in the text.

So I was just experimenting how much more it could increase when squeezed hard enough.

And it has been revealed that the aforementioned 380hz HD is a common problem of the Purifi X series.
 

098765

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Im afraid not, the experiment is incorrect. @Nuyes does not have knowledge of vibration measurement.
Because He is not measuring vibration perhaps? If you know well about measurements then please share your knowledge before just put down OP. I believe acoustic measurements too helps us in this situation to prove the point...
 
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