Need some help to understand these papers (FDA, multiamping)

[Gabs]

Hello,

Would somebody help me to figure if it's scam, snake oil or not ?
Sorry, the papers are in french.
The guy seems to really know what is doing, and as a newbie I'm often lost, but his statements seems right.
I had an Alientek D8 (FDA) with Cabasse speakers. But after it broke, I decided to buy Presonus active speakers.
I know that Vanatoo impemented FDA in their speakers : http://vanatoo.com/
But I'm not sure if FDA is going in the right direction.

Here are the papers : please read from 1 to 4
http://morphosis-audio.com/Actualites.html

Thank you very much !

 

[Kal Rubinson]

But I'm not sure if FDA is going in the right direction.

What is FDA? In this context, of course.

 

[Gabs]

Oh sorry. Maybe I could say a system from the digital source to the ears with the less possible electronical steps that manipulate (and degrade ?) the (sound) data. Let's say in order to have a "transparent" system.
It seems that Full Digital Audio stands for this purpose. But I'd may mistaking.

 

[Kal Rubinson]

Oh sorry. Maybe I could say a system from the digital source to the ears with the less possible electronical steps that manipulate (and degrade ?) the (sound) data. Let's say in order to have a "transparent" system.
It seems that Full Digital Audio stands for this purpose. But I'd may mistaking.

I had a hard time finding any information on FDA and very little on Full Digital Audio. Doesn't seem to have much penetration aside from car audio (Clarion) and 1-2 other websites. AFAIK, NAD has done some of this.

 

[Gabs]

Thank you for your help.

Amps
Alientek D8
FX-Audio D802 and D2160
SMSL Q5 Pro and AD18
Quloos QA690

And active speakers : Vanatoo T0 and T1

It seems that there are two major components :
- XMOS for the usb connection
- and a chip that is not a DAC

It seems there are two major manufacturer of FDA chips :
- Texas Instruments which is american : http://www.ti.com/lit/ug/slau376a/slau376a.pdf
- SMT Electronics wich is italian/french : http://www.st.com/resource/en/datasheet/cd00043329.pdf

Some manufacturers add analog circuit for headphones output and phono input. So no "pure "FDA" but hybrid ones.
And the french guy (of the paper) explains that multi-amplification with the right active filters (DSP), and more important the right assembling of speakers permits the graal of beating the most advanced analog systems for a fraction of the price.

 

[Gabs]

I found this. This is just the amp with usual speakers

 

[Gabs]

I also found this :
https://cdn.tgdd.vn/Files/2016/06/22/845324/cong-nghe-s-master-digital-amplifier-la-gi-3.jpg
S-master digital amplifier (Sony)

 

[Gabs]

And I just found that the "Marantz M-CR510" is also a "FDA" amp

 

[Gabs]

Last for today : FDA seems related to Class-D

 

[Gabs]

https://www.qobuz.com/ie-en/info/hi-res-guide/comparison-four-digital-amplifiers178041

 

[oivavoi]

I read the first and the last newsletter, and skimmed the other two. Definitely doesn't look like a scam. Seems legit. His main design goal is to achieve phase coherence through digital crossovers (a mixture of IIR and FIR filters), an approach which seems to be increasingly in vogue (check out the Kii Threes for example, or writings on the subject on the blog The Rational Audiophile). He also seems fairly well-read in psychoacoustics, which is reassuring.

The one area he doesnt seem to devote much attention to - which is often deemed important by "rational audiophiles" - is even dispersion with frequency. But his speakers might nevertheless sound good of course.

Difficult to know how these sound without auditioning them, but if you buy it as a DIY kit and it doesn't cost too much (any price given?), it seems to me like a fairly good offering. Wouldn't spend very large sums on them without auditioning them first, though.

 

[oivavoi]

Btw, I don't think he talks about FDA? What he mentions is "FDH" - filtrage digital hybrid - by which means a crossover filter which is a hybrid of the two most common crossover filter types, IIR and FIR.

EDIT: my mistake, he does actually mention FDA. But don't get a hangup on that. What amplifiers to use is the least important thing in a system like this. The important things happen in the speakers, the crossovers etc.

 

[Gabs]

Thank you very much for your help.
As far as I remember, the price of the system is around 2500€ without the subwoofer.
For me it's a lot, but if it is that good, I have to listen to it.

 

[Gabs]

And the guy wrote this about FDA : http://audiolalies.blogspot.fr/2015/03/derriere-le-micro-exactement.html
and that : http://audiolalies.blogspot.fr/2015/05/retour-sur-le-fx-audio-d802.html

 

[oivavoi]

Thanks, interesting.

2500 euros is not an insignifcant amount. I would also guess that you would need the sub to really get the best from this system. Small woofers which are forced to play deep bass usually generate so-called intermodulation or doppler distortion. On the other hand this system includes everything, so you only need a digital source and you're good to go. Can you get better sound for 2500 or 3000 euros? Possibly yes - for example if you build one of Linkwitz' creations yourself and use cheap amps (if you like the airy dipole sound), or if you put together a DSP-based DIY horn system (if you like the more direct horn sound). But only based on what he writes in the articles, I would also expect his system to sound better than most of the conventional systems you can get for a similar amount of money. You will have to listen and decide for yourself!

 

[FrantzM]

Hi

I am also interested. Not ready to just plunk 3000 euros ... without first listening but I seem to buy his premises. I however have a differentr view on low frequncy reproduction , mine is aligned with the works of the Welti, Devantier and Earl Geddes. Optimum bass in my experience seems to require multiple subs in most rooms... else .. I like the premises. Would have loved to see more measurements to back-up his claims.. Again more innovation coming from France/Europe while the rest of the High End community march stodgily toward more cables, exotic material etc (Europe is also home of one of the most famous and high performance grounding boxes ....)

The interesting thing is how far ahead John Dunleavy has been. To this day a serious listen to any Dunleavy design , from Duntech to those bearing his name will let you know.
I guess the proof is in the audition,. in the meantime I would like to see measurements, max SPL, THD, IM, etc ... Not much so far..

 

[Gabs]

Thank you very very much for your help "oivavoi" !

high performance grounding boxes ....

What ? ahahah

I fear auditionning a system not in my place, with my source. Even I know that I really need to listen to it.
And actually that what"s missing, measurements !
As the system seems really new, maybe we have to wait a little for the first benchmarks to be published.
When I will find something, for sure I will post it here !

And thank you FrantzM, because I found this. I have to study it !
https://pdfs.semanticscholar.org/00da/51387c572cfd27c0256cb15e44e976a1a72e.pdf

 

[Arnold Krueger]

Hi


I guess the proof is in the audition,. in the meantime I would like to see measurements, max SPL, THD, IM, etc ... Not much so far..

The attachment may be a helpful guide. The updates in green relate to a discussion of this issue on another forum.

The problem with listening evaluations that they are almost always performed with all kinds of very strong biases active. For example, level matching and actually comparing the identical same music are almost never done. Then there are the typical massive dead spots between auditions.

 

[Gabs]

Hi,

FYI :
http://patatorz.com/2018/03/11/syst...oute-du-10-mars-2018-sur-lyon/comment-page-1/

best regards

 

[Rene]

Hi,

FYI :
http://patatorz.com/2018/03/11/syst...oute-du-10-mars-2018-sur-lyon/comment-page-1/

best regards

FYI: It seems an FDA or Fully Digital Amplifier is one in which a PCM digital signal is converted directly to a pulse width modulated high frequency signal at high current and voltage.
So in effect, it is a power DAC.

This is in distinction to analog PWM power amps such as Hypex and IcePower in which the signal stays always in the analog domain.