Dynaudio Special 40 Upgrade: Big brand low quality ripoff or DIY Quackery?

[cwt]

On 08/04/2021 at 12:14 PM, kelossus said:

No one is questioning the accuracy of the measurements.  His whole critique is similar to what goes on at the Audio Science Review forum. They give you a million measurements to show a product is rubbish but never provide listening impressions before hand. That's what rubs me the wrong way.

Thats exactly where I went for other dynaudio measurements with similar peaky treble FR on this review ;  Dynaudio X14 Speaker Review | Audio Science Review (ASR) Forum

Amirs solution ? A narrow band peq around the crossover point  . Which raises the question of changing the intent of the speaker designer -another quandary well hashed already .. 

I like the fact that he uses the very latest equipment -Near Field Scanner System (NFS) (klippel.de)

; at least hard to equate what he says with others with sales to make I like to think 

[Darren69]

Anyone dont like their Special 40's after watching this, I'll give you five hundred for them. But be quick!! The arse will drop out of the market very quickly now, by this arvo it will only be three hundred!!

[Addicted to music]

21 hours ago, Al.M said:

I wouldn’t go for his total crossover overhaul but would change out the caps on the tweeter circuit to higher quality such as metal film units, which would be much lower cost and risk.

 

I’ve done that in speakers and found about a subjective 10-20% lift in tweeter clarity. The upgrade cost might be say $20 - 100 depending on how many in series caps are involved. Instead of changing the whole cap, one can use a cheaper but extremely high quality lower value 0.1uf cap piggy backed parallel to the existing one at about $10 each. Also, changing out $0.5-1 sand cast resistors on the tweeter path can make about 10% difference using $10 higher quality ones. There is one off them I the top let of pic below, might already be there.

 

If one doesnt like it, can be easily reversed by desoldering and virtually no sign of mods remain. The Bennic polypropylene caps in pic are about $5-10 each vs audiophile quality metal film versions that can be about $20-100. The Dynaudio low grade electrolytic caps can be about $3-10 each.

 

Other discussions here and my very rough interpretation of the crossover circuit schematic looks like my hand drawing. Perhaps others can improve on it https://forums.stevehoffman.tv/threads/dynaudio-special-forty.781463/page-3

 

 

i agree with you in  Changing the caps in series with the Tweeter.  However C5 is a high freq bypass to the bass driver so you’ll never here the benefits.  Always changed the components in series with the driver will likely make  the most change audibly...  Changing it to MKP whatever  make and sales pitch doesn’t necessary make it better, especially what’s regarded as “audiophile grade “ I’ve learnt that lesson well.   I hate to say it but some non polorised bipolar electrolytic does the job nicely, hence the reason why some one here on a previous post saids that the new mod sounded worst!  And the fact that the size and bulk of a bigger cap doesn’t do it justice as other electrical characteristics of MKP  come into effect.   
Note also it’s not the tweeter that’s the issue, it’s the non linear bass driver that shows up with several peaks he’s trying to flattened!   So he would have to change some of the values to knock out the 2nd peak.  

[Addicted to music]

13 hours ago, mjledme said:

I don't necessarily agree with Amir or have to diss him, but I hope to see his response to this, explaining the use of inductors to show the EMI of speaker cables...

 

 

And, if his point is that by using his updates you can transform the Special 40 to better speakers, that sounds not convincing to me at all...

There’s a perception that RF and EMI induced in speaker cables has an effect on SQ.   Unless you are living right next door to transmitting radio station or you have your gear near a microwave, or there is a fault with your equipment such as a RCA shielding issue and you’re using a moving coil cartridge on a Turntable,  the effects of speaker cables acting like an antenna that picks up micro volts: 1x (10) power of -6,  you’ll never hear it!   We are talking micro volts to volts required to move that driver, it’s will never happen as Amir has pointed out.   

[andyr]

15 minutes ago, Addicted to music said:

There’s a perception that RF and EMI induced in speaker cables has an effect on SQ.   Unless you are living right next door to transmitting radio station or you have your gear near a microwave, or there is a fault with your equipment such as a RCA shielding issue and you’re using a moving coil cartridge on a Turntable,  the effects of speaker cables acting like an antenna that picks up micro volts: 1x (10) power of -6,  you’ll never hear it!   We are talking micro volts to volts required to move that driver, it’s will never happen as Amir has pointed out.   

 

Well, just to let you know of an experience I had in my last house, Peter - about 15 years ago.  I upgraded from AKSA 100N+ modules on my bass panels to Hugh's subsequent 100w 'Soraya' modules.  When I switched them on ... I found I had a buzz coming from the bass panels (which wasn't there with the previous modules).

 

Hugh told me to put a 3nF cap across the spkr BPs on the back of the amp case - it seemed that the higher roll-off point of the Soraya design allowed RFI picked up by the spkr cables .to affect the final fb loop.  The cap drained this RFI to bround - and the problem went away.  (Hugh subsequetly added the 3nF cap to his circuit!   )

 

Andy

 

[Addicted to music]

1 hour ago, andyr said:

 

Well, just to let you know of an experience I had in my last house, Peter - about 15 years ago.  I upgraded from AKSA 100N+ modules on my bass panels to Hugh's subsequent 100w 'Soraya' modules.  When I switched them on ... I found I had a buzz coming from the bass panels (which wasn't there with the previous modules).

 

Hugh told me to put a 3nF cap across the spkr BPs on the back of the amp case - it seemed that the higher roll-off point of the Soraya design allowed RFI picked up by the spkr cables .to affect the final fb loop.  The cap drained this RFI to bround - and the problem went away.  (Hugh subsequetly added the 3nF cap to his circuit!   )

 

Andy

 

If you just changed amplifier modules and there seem to be a “buzz” doesn’t mean that your speaker wire is picking up “RF” far from it,  It wasn’t there b4, so why is there now after the module change? Every thing else is the same is it not?   If there was such a magnitude causing a “buzz”  you should be able to determine the freq via a scope and told you it’s coming from the “amp module “.  Hugh told you to place a 3,5nf cap across the speaker output terminal and it minimises it  tells me the the module was oscillating,     He then places a cap to reduced the “buzz” saids to me that one of the output device was  corrected, or he’s moved the HF point of the amp to limit the bandwidth so the oscillation is minimised.    It’s all in the design and the tolerances of the components...  I’m not being critical but the thing about low component count is that some components need assistance to guard against “self destruction”   The data sheet will tell you how to get the most out of that device,  such as;  use a cap in series with this value resistor to reduce the chances of self oscillating etc however in “audiophile land” less is best . 

Edited April 11, 2021 by Addicted to music

[muon*]

Andy explained the reason in his post.

 

Edit: actually It's Hughs explanation via Andy, and that's good enough for me.

Edited April 11, 2021 by muon*

[andyr]

2 hours ago, Addicted to music said:

If you just changed amplifier modules and there seem to be a “buzz” doesn’t mean that your speaker wire is picking up “RF” far from it,  It wasn’t there b4, so why is there now after the module change? 

 

 

AIUI, Peter - it was bcoz the new amp modules had an upper roll-off point of 80+kHz instead of 40kHz.

 

Before ... the roll-off point was low enough that the RFI picked up in the spkr cables didn't bother the amp.

 

Andy

 

[Al.M]

8 hours ago, Addicted to music said:

I hate to say it but some non polorised bipolar electrolytic does the job nicely, hence the reason why some one here on a previous post saids that the new mod sounded worst!

Agree with no guarantee of improvement but should give it try to to see if can improve. Bennic caps are generally average sounding.

 

Also, the issues discussed here about average quality, low cost crossover parts and average implementation is not uncommon in many high price and end speakers.

[Addicted to music]

5 hours ago, andyr said:

 

AIUI, Peter - it was bcoz the new amp modules had an upper roll-off point of 80+kHz instead of 40kHz.

 

Before ... the roll-off point was low enough that the RFI picked up in the spkr cables didn't bother the amp.

 

Andy

 

Hugh uses different device and he knows and I know that the devices he uses can be very unstable,  He should have limit the modules to roll of at 40khz if not close to audio 20khz .  It’s like I said, it’s a technique called bandwidth limiting that also limits slew rate,  usually using a low pass filter in the input or placing small value caps close to the gate and source of the output device.  All to prevent self oscillation, that can lead to destruction.   It has nothing to do with RF freq that ranges from 100khz to 1000MHz and above  that’s picked up by speaker cables, you can’t hear 40khz or above let alone greater than 100khz and above so it’s not RF that you ar hearing as you describe “buzz”Your issue with those modules are self induced and not via RF via speaker cables!  

Edited April 11, 2021 by Addicted to music

[andyr]

9 minutes ago, Addicted to music said:

it’s a technique called bandwidth limiting  usually ... or placing small value caps close to the gate and source of the output device.

 

The amp circuits I mentioned use transistors - not mosfets.

 

I just took his advice, Peter - and that solved my problem.

 

Andy

 

[Addicted to music]

36 minutes ago, andyr said:

 

The amp circuits I mentioned use transistors - not mosfets.

 

I just took his advice, Peter - and that solved my problem.

 

Andy

 

You really didn’t have a choice.

 

Depends on the transistors he’s using, and because it’s a transistor even less so to be effected by “RF” not all are stable in the audio region.  It depends on the design,  SIlicon chip uses the same Onsemi transistors for there power amp design, the same as the Magtech and has a serious output filter in place to keep it stable.  No such filter in a Magtech but that’s not why I bought one. 

Edited April 11, 2021 by Addicted to music

[muon*]

RF the cause, the oscillation being the result?

 

So the symptom of the noise heard from oscillation is the result of the RFI?

Edited April 11, 2021 by muon*

[Addicted to music]

15 minutes ago, muon* said:

RF the cause, the oscillation being the result?

 

So the symptom of the noise heard from oscillation is the result of the RFI?

external RF rarely causes oscillation, and if it did you wouldn’t be able to hear it!   Some components and circuit arrangement can self oscillate, if you hear a “buzz” it’s in the audible hearing freq not RF!   some designers refuse to follow data sheet guidelines and therefore introduce instability.   Audible “buzz” can also be caused by component tolerances,  I had to use a high cap value to get a output device stable, sometimes you need to go against the grain to get things to work.  If you work with opamps, some can’t be rolled in to the circuit of a different opamp because it has specific requirements.  Most audio opamps, in fact  all that are used for audio are heavily compensated so they stay stable. 

Edited April 11, 2021 by Addicted to music

[muon*]

I'll go with whatever Hughs explanation is, his amp, his design, he knows.

[LHC]

Since the OP started with a video from GR Research, here is another video from them discussing speaker cable audibility (and addressing ASR even).

 

 

[muon*]

He also does up a cheap pair of sony speakers and gets something very nice for the money.

[Addicted to music]

8 hours ago, LHC said:

Since the OP started with a video from GR Research, here is another video from them discussing speaker cable audibility (and addressing ASR even).

 

 

I assume The flat earthers that he’s referring to is ASR.  At least Amir shows you what is measured and what can be done than sit infront of a camera mumbling on about it and then starts selling speaker cable...for 17mins 

[NIN]

As a newbie for HIFI hobby.

 

I believe that we should keep a modest view on our development of science of human beings especially for HIFI audio technology.

 

The relationship between, electronic measurement, sound mesurement and perspectives of audiances are still not researched enough, that doenst mean it cant be, just maybe in terms of science, it is not that beneficial as researches on medicines or such.

 

That is why lots of people say investments on cables and power units are totally bullsh*t, but as a audiophile I can clearly tell the difference, even the measurement is the same.

 

In conclusion, weather a pair of speakers are good or bad, depends heaviliy on general public of audiances, and even some "professinals" say your speakers are not good, it doenst mean they are not good. I believe that Dyaudio are selling them with "speacial" in their names for solid enourgh reasons. I have seen few reviewers on youtube with quite "unique" view on some products, and I don't care much for what they say.

 

I wouldnt bother to upgrade my gears by someone saying they are not good in their measurements, as it is very subjective statement and not being tested by the market.

 

It is like once there was a magic liquid for petrol being sold on the market and the company claimed it is so powerful and mix it in the petrol in your car and you can save 20% petrol cost. If it is cheap and that effecitive why dont the petrol companies use that? If special 40 is such a rubbish and Dyaudio can improve it largely with $200 extra cost, why dont they fix it and charge for extra $500?

Edited April 12, 2021 by NIN

[muon*]

On 10/04/2021 at 12:31 PM, Al.M said:

 

 

 

 

 

Wow!

Is that really the cross over in a $6000 stand mount speaker?

[LHC]

13 hours ago, Addicted to music said:

I assume The flat earthers that he’s referring to is ASR.

I afraid you assumed correctly. He even heard that is an insult to 'true' flat earthers   . . 

[muon*]

27 minutes ago, LHC said:

I afraid you assumed correctly. He even heard that is an insult to 'true' flat earthers   . . 

The ASR cult are not known for their humour

 

Yeah, the real flat earthers objected to his use of the term

 

I like Danny, he uses measurements where they are and can be useful, but is not limited by them.

[broadz]

On 07/04/2021 at 5:52 PM, Addicted to music said:

One of the reasons why you should never design an amplifer around a set of speakers...  

Tell that to Bose

[Steffen]

20 hours ago, muon* said:

 

Is that really the cross over in a $6000 stand mount speaker?

 

That must be the $4000 version.  I hope for $6000 you also get L5, R6, C7 and PTC protection

 

[Decky]

On 11/04/2021 at 10:50 PM, LHC said:

Since the OP started with a video from GR Research, here is another video from them discussing speaker cable audibility (and addressing ASR even).

 

 

 

Nirvana had only one guitar  - unless he is talking abut a different band. Also, he is "demystifying" one religious belief with another - so typical. They are all false prophets - listen  to me - I have the only truth! 

 

I just do not understand who started with this crazy concept that ears are a legitimate measurement instrument, and even that they are more accurate than measurement microphones. Seriously! 

 

In the original video on moding the dyns - he did some decent work but conveniently forgot to comment on increased distortion from the tweeter after pushing it to work close to its resonant frequency. Oh, I forgot - his ears did not detect any distortion, right! 

Edited April 13, 2021 by Decky