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

[Holmz]

Thie may not translate well… “but @Nuyes you make it difficult to not like your work.”

 

[diddley]

You are only a temperary guest on his site where he can do what he wants, cause he is paying for it and is so free to give us space to react and discuss.
And i feel that as a privelidge

 

[Holmz]

You are only a temperary guest on his site where he can do what he wants, cause he is paying for it and is so free to give us space to react and discuss.
And i feel that as a privelidge

I get the nuance, but like a clash song… the question is: ”Should I stay or should I go?”

 

[diddley]

I get the nuance, but like a clash song… the question is: ”Should I stay or should I go?”

He's gone. and i do miss The Clash, last weekend i had a Clash weekend with Combat Rock and Sandinista. Great music and lyrics. yeah miss those years and music.

 

[BDWoody]

What has a member's number of posts got to do with conflict of interest?

Unfortunately, he couldn't stick around.

Another sock puppet from a previously banned member. There is much butthurt out there.

 

[Jimbob54]

Unfortunately, he couldn't stick around.

Another sock puppet from a previously banned member. There is much butthurt out there.

I would never have guessed ;-)

 

[julbo]

Thanks @Nuyes for this thorough review and saving me from a potential buyer's remorse
I've considered the Sointuva and almost pulled the plug before the price bumped, eventually chose the DIY route and plunged head on into the Directiva r1 adventure

 

[MAB]

Your test to determine the natural frequencies of the dowels consisted of what is known as a free–free condition. When mounted as a brace in the loudspeaker cabinet, the dowel fitment will likely approximate a somewhat lossy clamped–clamped support condition. Interestingly, it turns out that the natural frequencies of the dowel under those two quite different support conditions are the same. For example, refer to Blevins (1979), "Formulas for natural frequency and mode shape", Table 8-1, Single span beams.

Thanks. Appreciate the reference.

 

[samysound]

Thank you for sharing useful information and knowledge.

Here is some material I'd like to add for clarification.


View attachment 215257


1. THD, which does not increase proportionally, is rather modest at about 2.82V.









2.You may remember I tested the Sointuva WG with a hermetic one.
It is CNC machined to the same size as Purifi's Passive Radiator with great precision.






View attachment 215259





And as a result I can find similar resonances as well.

The problem with the Purifi driver you mentioned is related to the peak of the 3rd harmonic at 380hz.

However, I found that both the second harmonic and the higher harmonic had peaks at a constant ratio.

This is similar to the room mode that occurs in the listening space.


Through simple calculations, we can see that the length of the space that generates the first resonance of about 400 Hz is about 43 cm (16.9 inches).

And, coincidentally, the height of the Sointuva WG is 45cm (17.7inch) according to the manufacturer's specifications.

Considering the thickness of the speaker enclosure, I thought that this could be the room mode resonance due to the internal floor height.

And if this is the resonance caused by the room mode, this resonance also cannot increase linearly with respect to the output.
This is because the internal structure of this speaker itself is not a perfectly rigid wall.

I thought this was a sufficiently possible scenario.

And, this is why I added sound absorbing material inside this speaker.





And below is the measurement data of sample B.
Similarly, it can be found that everything from the second harmonic to the higher order harmonic soars in a similar frequency band.


View attachment 215258







If the cause of the THD pointed out in the original article is the 380hz/3rd harmonic inherent to the Purifi driver, it cannot explain this symptom.






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


@amirm , I'm sorry for tagging you carelessly.

I leave this question because I haven't gotten used to the way this website works yet.

Starting this thread was a huge process for me, and so was the outcome.

So there are some missing steps. Just like in this post.


Is there any way for me to add this to the body of the thread?
I am afraid that all this will evaporate through my hasty action.

Hi

your initial post seems to indicate that one speaker tested fine (e.g. low level of distortion peak at ~380hz) while the other had a higher level of distortion. Since this test was done with both speakers in the factory configuration (same amount of stuffing from factory); how can you then attribute the 380hz 3rd harmonic too a characteristic of the speaker box dimensions?

Seems more likely that it is related to the issues identified with mounting and torque of the woofer?

thanks!

 

[YSC]

Hi

your initial post seems to indicate that one speaker tested fine (e.g. low level of distortion peak at ~380hz) while the other had a higher level of distortion. Since this test was done with both speakers in the factory configuration (same amount of stuffing from factory); how can you then attribute the 380hz 3rd harmonic too a characteristic of the speaker box dimensions?

Seems more likely that it is related to the issues identified with mounting and torque of the woofer?

thanks!

I think the OP have stuffed something in the internal volume so the internal wall reflection is kind of reduced?

 

[samysound]

I think the OP have stuffed something in the internal volume so the internal wall reflection is kind of reduced?

yes, but according to the OP, both the speakers were measured in the "as-received" condition from the factory (with the same amount of stuffing) and only one of the speakers showed the raised 380hz peak while the other did not.

The stuffing was added to the speaker that had the raised 380hz peak; however, the woofer was also re-mounted for the speaker. So it may not have been the additional stuffing that improved the 380hz issue. It may have actually been the re-mounting of the woofer that changed this behavior. Since several things were changed between measurmeents, it is difficult to isolate the actual cause of the measurement discrepancies.

 

[bennybbbx]

the distortion measurement with continous tones let all speakers look mostly good. better is burst measure. the CEA 2010 burst can show the true. maybe you do such a burst at the critical frequency with speaker. the newest REW 5.20.9 since some days out have all features to do good compares. you can use the scope and generator and compare the loopback with the measure signal waveform of the burst. for this need near to speaker to minimize room reflections 1 - 5 cm away from speaker.

CEA 2010 look also bad with too much EQ . the burst is a fix frequency but a eq with much Q and much gain change the transient burst also in frequency .so its important to measure without any EQ.

I have attach a rew file with the setting that need to use the scope in REW. channel 1 is the input of microphone channel and channel 2 is the loopbacked signal for verify.

room reflections can only see at end of the burst and are very few. if there are some damping problems in speaker this can see

a good CEA 2010 burst of the slate fibre woofer of focal alpha 65 evo red line . the focal invert the signal so i need use - ch1 and so color is diffrent

this kali lp 6 speaker i think stereo width is very few in compare to other. here can see it shift the frequency. really strange because the burst have same frequency all the time. but i do lots of measures diffrent frequencies but result stay same

frequency shift happen also when use EQ

here are some results with EQ. there is no speaker use. i put the output for aktive speaker to input of usb soundbox

this is with dirac correction(which i think it sound bad in clarity and stereo) maybe thats the reason

this is linear phase

this is normal EQ (minimum phase)

 

[krabapple]

apparently the bolt torques were not altered by the owner or tester. see post by @Nuyes in response to my question:

I meant, "I'm really not sure if this is what you [PeteL] meant, so I am asking you if this is what you meant"

But thanks anyway.

 

[hmt]

the distortion measurement with continous tones let all speakers look mostly good. better is burst measure. the CEA 2010 burst can show the true. maybe you do such a burst at the critical frequency with speaker. the newest REW 5.20.9 since some days out have all features to do good compares. you can use the scope and generator and compare the loopback with the measure signal waveform of the burst. for this need near to speaker to minimize room reflections 1 - 5 cm away from speaker.

CEA 2010 look also bad with too much EQ . the burst is a fix frequency but a eq with much Q and much gain change the transient burst also in frequency .so its important to measure without any EQ.

I have attach a rew file with the setting that need to use the scope in REW. channel 1 is the input of microphone channel and channel 2 is the loopbacked signal for verify.

room reflections can only see at end of the burst and are very few. if there are some damping problems in speaker this can see

a good CEA 2010 burst of the slate fibre woofer of focal alpha 65 evo red line . the focal invert the signal so i need use - ch1 and so color is diffrent

View attachment 215333


this kali lp 6 speaker i think stereo width is very few in compare to other. here can see it shift the frequency. really strange because the burst have same frequency all the time. but i do lots of measures diffrent frequencies but result stay same

View attachment 215334


frequency shift happen also when use EQ

here are some results with EQ. there is no speaker use. i put the output for aktive speaker to input of usb soundbox

this is with dirac correction(which i think it sound bad in clarity and stereo) maybe thats the reason

View attachment 215335


this is linear phase


View attachment 215336

this is normal EQ (minimum phase)

View attachment 215339

Imo it makes no sense to really draw conclusions of room EQ with measurements taken from a few cm away. Of course it will change the impulse in some way at the eqed frequency. That's what EQ is supposed to do.

 

[AudioJester]

I think the OP have stuffed something in the internal volume so the internal wall reflection is kind of reduced?

This kind of post is a big problem in this thread. People not reading and comprehending the sequence of events. This is also how the manufacturer has flipped things and claims the poor measurement was a result of speaker tampering/modification.

The OP has made it clear on a number of occassions that measurements were done on speaker as delivered. After not getting anywhere with the manufacturer, he then went about fixing it while carefully documenting the process.

 

[bennybbbx]

Imo it makes no sense to really draw conclusions of room EQ with measurements taken from a few cm away. Of course it will change the impulse in some way at the eqed frequency. That's what EQ is supposed to do.

I write about EQ because the answer from the speaker developer was. " we have a mitigation for this effect". if they use some L C eq is maybe not so good. this dirac screesnhot test only 1 frequency and it use no speaker with the dirac screenshot. i connect the cable that go to speaker to usb soundcard input. klippel have too such a tone burst measurement. https://www.klippel.de/fileadmin/kl...System/PDF/S44_TBM_Tone_Burst_Measurement.pdf

I think such a tone burst measure is usefull for this speaker. then can see what happen to the burst if it resonate because of the passive speaker.

 

[AudioJester]

Unfortunately, he couldn't stick around.

Another sock puppet from a previously banned member. There is much butthurt out there.

Am I the only one who finds it somewhat entertaining watching these guys pop back repeatedly with ridiculous posts?

Theses guys hate each other more than ASR - you should create a subforum for them where they can duke it out lol

 

[samysound]

6. Improvements

I sealed the tweeter parts.

View attachment 214831View attachment 214832View attachment 214833View attachment 214834View attachment 214835







Regarding insert nuts.
The insert nuts at the unit joint just fell out when pushed physically and thus caused leakage.

So I sealed it myself. (Picture below.)




View attachment 214836View attachment 214837







There are more issues I found during the improvement process.





View attachment 214838






Usual insert nuts have a tube at the end and seals a bit when it is pulled




View attachment 214839








But I found some insert nuts without those sealing tubes.


I cannot confirm whether or to what extent this contributed to leakage of enclosure but the inconsistent use of materials is enough to be criticized.

Another jaw dropping issue was that





View attachment 214840







Insert nuts should be installed like the picture above, but when I disassembled the other Sointuva WG piece which didn’t have an issue,



View attachment 214841






I found an unassembled insert nut.
A clear apology and follow up actions is required from the manufacturer.




Organizing the internal wiring.

View attachment 214842






The existing wiring was not fixed and might have caused a noise by vibration so...




View attachment 214843View attachment 214844






I organized it as above.

Hi, can you please post the emails/questions that were actually sent to the manufacturer? That would help with some context and the full picture for the manufacturers email responses you have shared.

 

[mga2009]

@Nuyes
Thanks for all the information and data!

Controversy aside, what is shown is that, even the smallest things (amount of filling, gap in the binding posts, uneven seal between waveguide and tweeter, loose cables, etc.) can -substantially- affect the performance of a speaker, even if its built with the very best parts (Purifi components and beryllium tweeter).

 

[samysound]

@Nuyes
Thanks for all the information and data!

Controversy aside, what is shown is that, even the smallest things (amount of filling, gap in the binding posts, uneven seal between waveguide and tweeter, loose cables, etc.) can -substantially- affect the performance of a speaker, even if its built with the very best parts (Purifi components and beryllium tweeter).

Im not sure you can really make that conclusion from the OPs study. The various variables (stuffing, sealing and driver mounting) were not sufficiently isolated in the testing.