Dynaudio Special Forty - Review & Measurements by Erin

[amirm]

Yeah, just quoting what they posted. Their biggest speaker Is the Confidence 60

146 lbs, 64 inches

Thanks for finding that. Seems like someone was defending building the Jupiter system!

146 pounds is OK. 64 inches may be right at the edge of past what is possible.

 

[tktran303]

This old thing was released in 2017, or earlier IIRC.

It’s an update for the classical 6.5” 2 way bookshelf release to coincide with Dynaudio’s 40th anniversary,

Sadly there’s nothing innovative or new under the sun with this speaker.


At least with the JBL 4329p that Erin reviewed before this you get a wireless connectivity and built in amps, and a bigger 8” midwoofer and DSP for more extended bass and higher output. Despite having better directivity matching in the crossover, even the wave-guided tweeter couldn’t reach down to hand over to the mid-woofer; so the JBL features the same (or worse) cone breakdown and shows the cone resonance and cone/surround edge mismatch causing resonances 500-1000Hz and the little hole.

You picks your poison…

 

[wwenze]

I'm starting to wonder if it is possible that we have subjective preference targets for speaker FR and directivity.

After all the "start wide then let the woofer narrow and then let the tweeter go wider at XO frequency and then go narrow again" was the standard practice of speakers in the past. The frequency also coincides with headphone target curve that I wonder if headphone target curve is like that because we listen off-axis.

 

[VintageFlanker]

I'm starting to wonder if it is possible that we have subjective preference targets for speaker FR and directivity

We do:

 

[tktran303]

Just a slight hiccup; do we really know what the ideal slope is?

Is the 7dB tilt between 20Hz and 20Khz for the KH420 ideal?

Or 6dB?
Or 8dB?


More or less?

And what if it was mastered on speakers that measured more like the old insert-speaker-X here.

I wonder if the ITU, NHK or Fraunhofer or other organisation should set a mastering reference.

Which one has the better spin?

Feel free to criticise both; because they are both my speakers.

I wonder whether it depends on the room, the listening (program) material and listener preference?

 

[Soniclife]

This is due super conservative spec for NFS. I was very worried about this prior to purchase but the local rep assured me that the stand can handle far more than that. And they were right. I have put 110 pound/50 Kg speakers on the post with zero concern. It is extremely solid but just not wide. So I augment it with a larger plate. Unless one gets into 200+ pounds, I would not worry about it. Strange that they have not realized this after getting the unit.

It might be a legal caution thing, if the manufacture only specs 5kg and a worker gets injured they could be invalidating their insurance.

 

[Matias]

From Dynaudio

https://www.facebook.com/DynaudioGroup/photos/a.254075897969470/4201505769893110

We actually have a NFS and used it for verification and improvement of the measurement setup for Jupiter. In the daily work we prefer to use the measurement system in Jupiter due to the following reasons:

1. It takes about 6-10 hours to get a measurement with the same accuracy we can achieve in Jupiter in approximately 20 mins.

2. We have found that loudspeakers with multiple acoustic sources (drivers and ports) require bespoke measurement setups specific to the speaker being measured. Investigating the required setup takes time and needs to be repeated for individual speaker models.

3. The height the NFS can measure is limited so we can’t measure our tallest speakers.

4. The requirement for material handling and leaving the lifting equipment attached for any speaker that weighs more than 5 kg is problematic. We have to make custom harnesses for each speaker to avoid acoustic reflections from the lifting equipment (very important for high frequency measurements).

In short we can get similar results with the NFS compared to Jupiter, it just takes significantly longer and is quite impractical with regards to the material lifting. We have spent quite some time looking at the measurement differences between differing measurement systems and we think Jupiter gives us the accuracy we need in a reasonable time frame

With the cost and space of their Jupiter room in the millions IIRC, they could have bought 10x NFS and run projects in parallel. Low resolution on prototypes, high resolution on release candidates. Who is faster now?

Also if they have both and still release such a speaker, what are they using it for anyway? Look at Ascend, also got an NFS and are releasing stellar speakers since.

NFS can't handle large speakers? Magico disagrees. Is that large enough for them??

 

[VintageFlanker]

Magico disagrees. Is that large enough for them??

I remember this impressive video...but... Did Magico published any Spin since?

 

[Matias]

I remember this impressive video...but... Did Magico published any Spin since?

Nope...

 

[NTK]

This Magico test would be acceptable if you only need to do it once in the product life cycle.

If you need the test results for product development, i.e. multiple iterations of tweak / re-test / tweak / re-test cycles, this test will become tiring very quickly.

 

[ctrl]

This Magico test would be acceptable if you only need to do it once in the product life cycle.

If you need the test results for product development, i.e. multiple iterations of tweak / re-test / tweak / re-test cycles, this test will become tiring very quickly.

But a professional speaker design these days shouldn't require an NFS for every iteration for things like the "multiple iterations of tweak / re-test / tweak / re-test cycles" you describe.

After the design parameters are set, you start with a simulation of the speaker. Depending on the level of detail of the simulation, this can even already show possible cabinet and BR port resonances and you can try out different variants directly on the computer.

The simulation provides at least a complete spinorama for each driver of the loudspeaker. This allows you to simulate the finished LS in advance in XO programs such as VCAD. If the simulation provides realistic electrical data (e.g. impedance, excursion,...) in addition to the acoustic data, you can even determine the possible component costs for a passive version in advance.

When the first prototype is built, then one can already track down most resonances via near-field and impedance measurements (done in a few minutes) and minimize them by iterative changes.

For the optimized prototype, a complete spinorama is then created for each individual driver (plus impedance measurements) and the final XO can then be created in the XO program, or the final version can be created iteratively through XO changes in XO simulation and listening tests of the real speaker with the different XO versions.

For the final speaker version it is enough to measure the on-axis frequency response, additionally the on-axis FR of the single drivers and if these matches with the XO simulation, the loudspeaker is ready.
If you want to be absolutely sure, you can also create a complete spinorama of the final LS (but if the XO simulation program is good, it is not really necessary) - If you are in possession of a Klippel NFS, you do this, of course

So if the development of the loudspeaker is well planned, for an X-way loudspeaker, you need X + 1 NFS cycles for the complete development.

 

[DSJR]

Dynaudio seem to have several 'sound balances' in each product family, the best possibly the still expensive cheaper ones (not so 'showy-impressive) amnd I suspect their pro range is different again, as is the Focus range. I heard these Special Forty's on one occasion and they didn't impress at all. Some cheaper Q Acoustics could sound better overall and they're well finished to boot! A dealer I know sell loads of Dynaudio's and like the upper mid 'edge' as it 'sounds more detailed' to them!

 

[Soniclife]

But a professional speaker design these days shouldn't require an NFS for every iteration for things like the "multiple iterations of tweak / re-test / tweak / re-test cycles" you describe.

After the design parameters are set, you start with a simulation of the speaker. Depending on the level of detail of the simulation, this can even already show possible cabinet and BR port resonances and you can try out different variants directly on the computer.

The simulation provides at least a complete spinorama for each driver of the loudspeaker. This allows you to simulate the finished LS in advance in XO programs such as VCAD. If the simulation provides realistic electrical data (e.g. impedance, excursion,...) in addition to the acoustic data, you can even determine the possible component costs for a passive version in advance.

When the first prototype is built, then one can already track down most resonances via near-field and impedance measurements (done in a few minutes) and minimize them by iterative changes.

For the optimized prototype, a complete spinorama is then created for each individual driver (plus impedance measurements) and the final XO can then be created in the XO program, or the final version can be created iteratively through XO changes in XO simulation and listening tests of the real speaker with the different XO versions.

For the final speaker version it is enough to measure the on-axis frequency response, additionally the on-axis FR of the single drivers and if these matches with the XO simulation, the loudspeaker is ready.
If you want to be absolutely sure, you can also create a complete spinorama of the final LS (but if the XO simulation program is good, it is not really necessary) - If you are in possession of a Klippel NFS, you do this, of course

So if the development of the loudspeaker is well planned, for an X-way loudspeaker, you need X + 1 NFS cycles for the complete development.

Thanks for that. It's pretty much as I assumed a proper engineer would do it, but nice to have it layed out.

 

[NTK]

So if the development of the loudspeaker is well planned, for an X-way loudspeaker, you need X + 1 NFS cycles for the complete development.

The only way you can do that is when you don't innovate. I know. My entire professional career is in product design and development.

 

[ctrl]

The only way you can do that is when you don't innovate. My entire professional career is in product design and development.

I am only a hobby loudspeaker designer, in my developments the innovation usually takes place in simulation and the better the simulation, the more diverse the possibilities for innovation.

Of course, you have to carefully weigh the effort of simulation and building a new prototype, which has to be re-measured.

I just wanted to express that a professional loudspeaker manufacturer in the design of a speaker, due to today's possibilities, no longer has to complete every change to the speaker via the construction of a prototype and new measurements. Therefore, the 22h measurement time, as mentioned above with the example of Magico, does not occur too often when using today's possibilities.

@René - Acculution.com could certainly tell us more about today's speaker design possibilities (and has already)

 

[René - Acculution.com]

I am only a hobby loudspeaker designer, in my developments the innovation usually takes place in simulation and the better the simulation, the more diverse the possibilities for innovation.

Of course, you have to carefully weigh the effort of simulation and building a new prototype, which has to be re-measured.

I just wanted to express that a professional loudspeaker manufacturer in the design of a speaker, due to today's possibilities, no longer has to complete every change to the speaker via the construction of a prototype and new measurements. Therefore, the 22h measurement time, as mentioned above with the example of Magico, does not occur too often when using today's possibilities.

@René - Acculution.com could certainly tell us more about today's speaker design possibilities (and has already)

A baseline simulation that fits the initial prototype is the typical way to go. Here, measurements are extremely important, and the more the better. Standard, vacuum, loaded in different ways. Material values are then established as best we can. And then follows perhaps 10-50 virtual prototypes, with zero measurements taking place. The simulation will give a much better insights as to what is actually going on (when done correctly). And then hopefully just one final prototype in physical form. But that is probably not typical for most companies.

 

[restorer-john]

NFS can't handle large speakers? Magico disagrees. Is that large enough for them??

They fully Macgyvered it with four suspended cables and a base! Otherwise the whole thing would have collapsed in a pile of twisted aluminium.

Dynaudio can put any speaker, of any size in the Jupiter facility. They could develop and/or test massive PA speakers, huge arrays etc.

 

[fineMen]

Back to the speakers, KEF R3 Meta for 2.2k usd a pair is a far better measuring speaker and costs less. No brainer imo.

Exactly, as we now have a standard on speaker measurement and how to read it, there is no need to accept anything other than the best price/performance ratio in a given form factor. The many alternatives are obsolete.
The Dynaudio exemplifies on this. Low performance at high cost. Reason: unsolved, well known problems that other have solved perfectly. Perfectly means, there is finally no solid reason to do better. Let's support those companies that do their homework rather than other who exploit marketing tech.

So much on the 'no brainer'

 

[René - Acculution.com]

This would be an interesting case to take on. Special 45 for 2023 ;-) I don't think there was any pressure phase or step response shown, which would have been very informative as to evaluate the effect of sticking to first order filters.

 

[restorer-john]

Exactly, as we now have a standard on speaker measurement and how to read it, there is no need to accept anything other than the best price/performance ratio in a given form factor. The many alternatives are obsolete.
The Dynaudio exemplifies on this. Low performance at high cost. Reason: unsolved, well known problems that other have solved perfectly. Perfectly means, there is finally no solid reason to do better. Let's support those companies that do their homework rather than other who exploit marketing tech.

So much on the 'no brainer'

What are you talking about? Seriously. (this will be funny to hear your answer)