• 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!

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

Doodski

Grand Contributor
Forum Donor
Joined
Dec 9, 2019
Messages
20,745
Likes
20,757
Location
Canada
THREAD NOTICE: In the spirt of getting back to and keeping this thread on Topic. Any further comments about Bans will be treated as off topic and deleted. Continued posts will earn a Thread ban. Please and thank you for your understanding and assistance.
Just read your comment... Hope I didn't cross any line with my comment. :D
 

Doodski

Grand Contributor
Forum Donor
Joined
Dec 9, 2019
Messages
20,745
Likes
20,757
Location
Canada
After reading most of this thread, one piece of advise I'd offer to the maker is ... "measure twice, cut once". Hastily constructed products are bound to be a crap shoot as I'm sure you now realize. Your name is on the product and if you've got a small workforce doing assembly sometimes you've got to check what's happening in your name. If you are personally going from a-z in the build ... slow down and get it right. Stuff like this will kill you and your business like a heart attack.
That's what a QA/QC technician or engineer is for. I've been a QA/QC tech for downhole tools and it was constant observation and double checking product. It pays to have one if required.
 

Xulonn

Major Contributor
Forum Donor
Joined
Jun 27, 2018
Messages
1,828
Likes
6,311
Location
Boquete, Chiriqui, Panama
Driving other's traffic to your site? I can't resist posting this:

 

MAB

Major Contributor
Joined
Nov 15, 2021
Messages
2,135
Likes
4,779
Location
Portland, OR, USA
Just read your comment... Hope I didn't cross any line with my comment. :D
bugs-bunny-cross-the-line.gif

You deserve some slack!
 

beren777

Senior Member
Joined
Feb 25, 2020
Messages
339
Likes
589
View attachment 215174

If 380hz is inherent in the motor how did they even get this graph.

Isn't this infinite 'baffle' measurement?

It is a big disappointment with their decision to hide the problem with cheating. Or shall I say unprofessional method?

 

AudioJester

Addicted to Fun and Learning
Forum Donor
Joined
Jan 7, 2020
Messages
912
Likes
1,211
There are a number of boutique Australian speaker manufacturers. Osborne, Krix, Hulgich, VAF, Legend, Kyron, Lenard, Pitt and Giblin etc.
One generalised comment is they are usually exceptional build quality.
The quality of this speaker is disappointing.
 

DualTriode

Addicted to Fun and Learning
Joined
Oct 24, 2019
Messages
893
Likes
593
That depends on the degree of narcissism. What really bugs me is the degree of mistrust sometimes is shown here. Everybody is assumed the worst. Gene is bribed by manufacturers, Erin just wants to divert traffic. That's borderline paranoia and creates a toxic environment.

Be careful, "Borderline Personality Disorder" is reserved, it is a personality disorder all of its' own.

"Why don't you appreciate it more when I prove to you how wrong you are?" It gets personal. People get angry. A good sociopath learns to control his feelings and the feelings of others. This is called emotional maturity or EQ.

 
Last edited:

The_Lone_Funman

New Member
Joined
Jun 28, 2022
Messages
2
Likes
9
I don't really want to participate in the digression here, but thank Nuyes for his outstanding review, loudspeaker equivalent of very impressive differential diagnostics, translation, formatting and commitment. As well, though perhaps it goes without saying thank the fearless leader of ASR for hosting all this to his main reviews page. Nuyes I hope we see more from you in the future!
 

jhaider

Major Contributor
Forum Donor
Joined
Jun 5, 2016
Messages
2,822
Likes
4,514
I'm convinced with March Audio's response, they recognized the mistake of not sealing the binding posts. These things happen.

That does beg the question of why he’d spec a terrible garbage snake oil part that’s clearly not suitable to purpose, though.
 

fluid

Addicted to Fun and Learning
Joined
Apr 19, 2021
Messages
691
Likes
1,196
The exact cause was unknown.
All I could do was repeat as many different comparative measurements as possible.
As a result, various leaks were visually confirmed and resolved, and no problems were found in the passive radiator.

Adding an inner sound absorbing material was one of the things I could do, and it happened that it improved the symptoms.

And by adjusting the degree, I found the best setting possible (the goal is to allow the harmonic distortion of the problem band to increase proportionally with the output), and apply this to sample B as it is, and then sample B All I have to do is re-test to make sure it is not broken.

Aside from that, of course, both speakers had significant binding force leaks, so this is also one of the crux of the issue I raised.
There is enough measured data to discern the root cause of the peak in harmonic distortion in the bad sample. The Purifi Extended range driver can exhibit a resonance at that frequency when the driver is mounted in such a way that the mass spring oscillates. This is level dependent and why the distortion will not then follow a linearly increasing trend.

When the mass spring is damped or not excited there is no problem, evidenced by measuring the driver with the magnet on the table.

Adding the extra stuffing was not the right course as evidenced by the Impedance response, but the combination of that and however the driver was then remounted stopped the mass spring from being excited enough to cause higher distortion.

March's solution to mounting the Purifi driver to avoid exciting the oscillation was to use rubber well nuts and a specific torque pattern. Somehow in one speaker this has gone wrong and resulted in the distortion peak. Chasing that problem has highlighted the non sealed binding posts, this is a manufacturing defect but I think somewhat of a red herring in identifying the cause of the distortion peak.

Designing high performance speakers and tracing the true cause of issues is not a simple business. It is easy to change more than one variable at a time and come to an incorrect conclusion.
If 380hz is inherent in the motor how did they even get this graph.

Isn't this infinite 'baffle' measurement?

It is a big disappointment with their decision to hide the problem with cheating. Or shall I say unprofessional method?
This is a most unfair comment, particularly when aimed at a manufacturer that provides a high level of data about their drivers to consumers. Be wary of letting dissatisfaction with March flow over.

The distortion occurs when the driver is mounted in such a way that the mass spring oscillates. The need for careful mounting is the price to pay for making a driver capable of such high excursion and low bass in a small form factor.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
44,368
Likes
234,386
Location
Seattle Area
The distortion occurs when the driver is mounted in such a way that the mass spring oscillates. The need for careful mounting is the price to pay for making a driver capable of such high excursion and low bass in a small form factor.
Then it should have been in some kind of app note. Not having it means people don't know to deal with it.
 

Chrispy

Master Contributor
Forum Donor
Joined
Feb 7, 2020
Messages
7,751
Likes
5,910
Location
PNW
The mechanic in me is fascinated by what the proper tightening sequence and torque is for the mounting bolts....
 

SDC

Senior Member
Joined
Oct 3, 2019
Messages
328
Likes
508
Location
S.Korea
Yes I read that. But I don't get the point. Are their baffle made of SUS or something? They grounded the motor for Measurement? Is it normal for manufactures to ground the unit completely for their datasheet? It is first time I see such problem but as a costumer I don't feel comfortable.
 

SDC

Senior Member
Joined
Oct 3, 2019
Messages
328
Likes
508
Location
S.Korea
Yes I read that. But I don't get the point. Are their baffle made of SUS or something? They grounded the motor for Measurement? Is it normal for manufactures to ground the unit completely for their datasheet? It is first time I see such problem but as a costumer I don't feel comfortable.
Anyway I ordered 200*200 Al6061 test baffle for it so I'll see it in person
 

fluid

Addicted to Fun and Learning
Joined
Apr 19, 2021
Messages
691
Likes
1,196
Then it should have been in some kind of app note. Not having it means people don't know to deal with it.
Sure but sometimes smart people don't imagine that an obvious problem to them isn't so to everyone. Why GPS devices no longer tell you to make an immediate U turn.
Yes I read that. But I don't get the point. Are their baffle made of SUS or something? They grounded the motor for Measurement? Is it normal for manufactures to ground there unit completely for their datasheet? It is first time I see such problem but as a costumer I don't feel comfortable.
I think you misundertand, grounding in this context doesn't mean electrically, it means allowing the reaction forces to be physically grounded. It is rigidly mounting the driver by the frame that causes the problem. Order some rubber dampers or mount the driver by the magnet.

See this here from Linkwitz
https://www.linkwitzlab.com/frontiers_2.htm#N
 

SDC

Senior Member
Joined
Oct 3, 2019
Messages
328
Likes
508
Location
S.Korea
Sure but sometimes smart people don't imagine that an obvious problem to them isn't so to everyone. Why GPS devices no longer tell you to make an immediate U turn.

I think you misundertand, grounding in this context doesn't mean electrically, it means allowing the reaction forces to be physically grounded. It is rigidly mounting the driver by the frame that causes the problem.

See this here from Linkwitz
https://www.linkwitzlab.com/frontiers_2.htm#N

No I do understand is means mechanical grounding. But the IB test I know is consisted of test baffle, driver mounted to it, and baffle wings. And If baffle-motor is resonating and causing problem why is it not seen on the Purifi datasheet?
 

YSC

Major Contributor
Joined
Dec 31, 2019
Messages
3,194
Likes
2,570
Reading through all those derailing posts and come back to the topic: the speaker looked nice, priced reasonably with the SOTA drivers, and measured well when built correctly. With the logical finding of the OP in a random pair of speakers discovering so much location where he can improve after measuring and detecting a defective unit is underwhelming for QC. Personally I loved how this looked and measured, if only March did go beyond his defensiveness in every single unit I might buy it in near future for a venture into the passive world. But sadly his very defensive attitude on reply keeps me away. I can’t gamble that money on a crapshoot on the speaker being both well built, and that I don’t have the Klippel to easily detect these kind of defect.

Now I guess if I really love the purifi driver I might be better off buchardt A500 special edition
 

Axo1989

Major Contributor
Joined
Jan 9, 2022
Messages
2,804
Likes
2,806
Location
Sydney
That depends on the degree of narcissism. What really bugs me is the degree of mistrust sometimes is shown here. Everybody is assumed the worst. Gene is bribed by manufacturers, Erin just wants to divert traffic. That's borderline paranoia and creates a toxic environment.
I perceive a degree of that also. It isn't sufficient to outweigh the value of this forum, but I would (and hopefully do) take more care choosing and posting words to that effect.

I'd also say that accusations are often projection, so they cause me to be more circumspect wrt the veracity of a poorly-worded or overstated accusation/inference. I discount the OP somewhat: there is some interesting data that I appreciate, but analysis and inference shows some carelessness.
 
Last edited:

fluid

Addicted to Fun and Learning
Joined
Apr 19, 2021
Messages
691
Likes
1,196
But the IB test I know is consisted of test baffle, driver mounted to it, and baffle wings. And If baffle-motor is resonating and causing problem why is it not seen on the Purifi datasheet?
Most likely because they isolated the driver from the baffle with damping or mounted it via the magnet, or they measured it at an SPL level where the resonance wasn't excited.
 
Top Bottom