"Viraj la dreapta" - Ce rost are un preu phono MM in 2017?

[hpavictor]

Subiectul Paraset era important ... da' daca ai permis ca trolul ala sa-si bata joc de subiect , voi proceda si eu ca el .

[ex.escu]

Posesorul de cd viseaza la :

 

N= 6n + 1,8 (db) unde n= 16,pentru 16 bit.

N= 97,8 db ,teoretic.

Practic la nivele reduse,sub -50 db dac-ul are probleme cu distorsiunile ,la fel la nivele de la 0 la -12 db ,si dinamica reala ajunge la nivele de 40 db, e drept fara zgomot de fond.

Multi vor spune "blasfemie",dar cele de mai sus din pacate sunt reale ,unele performante se obtin in detrimentul altora.

Craciun fericit si auditii placute!

[dark_angel]

Posesorul de cd viseaza la :

 

N= 6n + 1,8 (db) unde n= 16,pentru 16 bit.

N= 97,8 db ,teoretic.

Practic la nivele reduse,sub -50 db dac-ul are probleme cu distorsiunile ,la fel la nivele de la 0 la -12 db ,si dinamica reala ajunge la nivele de 40 db, e drept fara zgomot de fond.

Multi vor spune "blasfemie",dar cele de mai sus din pacate sunt reale ,unele performante se obtin in detrimentul altora.

Craciun fericit si auditii placute!

De la 70dB la 97dB e ceva diferenta fiind o scara logaritmica, asta fiindca ai ales 16b :P ca la 24b deja batea la ochi

Ce distorsiuni baga un DAC sub 50dB? In foaia de catalog a lui tda1541 in pag.8 vad altceva. Si totusi are vreo 30 de ani de cand a aparut pe piata, nu e chiar din zilele noastre.

Il las pe TraianB sa te intrebe daca ai masurat si cum ai ajuns la aia 40dB gama dinamica reala.

 

 

Subiectul Paraset era important ... da' daca ai permis ca trolul ala sa-si bata joc de subiect , voi proceda si eu ca el .

Daca il deschideai la bodega nu se mai intampla asta.

[hpavictor]

Mda , nu comentez activitatea moderatorului de acolo ...

[sesebe]

Posesorul de cd viseaza la :

 

N= 6n + 1,8 (db) unde n= 16,pentru 16 bit.

N= 97,8 db ,teoretic.

Practic la nivele reduse,sub -50 db dac-ul are probleme cu distorsiunile ,la fel la nivele de la 0 la -12 db ,si dinamica reala ajunge la nivele de 40 db, e drept fara zgomot de fond.

Multi vor spune "blasfemie",dar cele de mai sus din pacate sunt reale ,unele performante se obtin in detrimentul altora.

Craciun fericit si auditii placute!

 

Asta poate s-o intimpla la DAC-urile filterless, cu iesirea directa fara filtrare la iesire, eventual si fara oversampling cum e moda printre puristii audiofili dar la un DAC bine facut nu are cum sa se intimple.

Astept o explicatie si demonstratie mathematica, eventual si cu masuratori.

La DAC-ul meu am facut masuratori cu un analizor spectral de genul acesta (R&S®FSW4) si nu se intimpla asa ceva, deci astept o demonstratie din partea ta.

E usor sa sustii ceva verbal, sa mai si demonstrezi e mult mai greu, deci astept demonstratia.

Editat Decembrie 24, 2017 de sesebe

[hpavictor]

Te invit sa folosesti mai mult respect in adresarea catre @ex.escu ...

Cu siguranta am avea toti de castigat de pe urma unor explicatii detaliate , insotite de argumente tehnice de mare valoare .

Multumesc anticipat !

[ex.escu]

Subiectul a mai fost discutat,am postat atunci un articol din Radiohobby 2/1998, scris de un profesionist,Dl.N Suhov, in care erau " demontate" unele mituri audiofile,inclusiv acesta.

[franzm]

La pagina 18.

[hpavictor]

Aici aveti un extras :

 

 

[dark_angel]

Dragi tovarsi si pretini (cum spunea un nene la inceputul cuvantarii sale multi ani in urma) sa lasam politetea deoparte ca nu suntem la vreun cenaclu literar sau la vreo serbare de 9 mai sa tinem cont si de grade. In articolul ala agenturilii pardon autorul zice cam asa:

 

 

Another common "audio confusion" is that the CD supposedly provides a larger dynamic range than an analog compact cassette (KK).
In this case, the quantization noise formula NkB is given as the main argument: NkB = 6N + 1.8 [dB], where N is the level of quantization.
For CD, N = 16 is applied, hence the theoretical level of quantization noise is Nkv. CD = 6x16 + 1.8 = 97.8 dB. With someone's light hand, this value is taken as the dynamic range of the CD. Given that the best QC signal / noise ratio (without noise reduction systems) of the order of 55 dB, and the conclusion of more than 40 dB benefit CD. But we must not forget that the principles of analog KK and digital CD are radically different, that's why the methods for measuring KK are incorrect for estimating the dynamic range of CDs. In KK, the dynamic range at the bottom is really determined by the noise level, but this does not mean that the situation is the same for the CD '. Looking at Fig. 4, which depicts the typical dependencies of the coefficient KK of nonlinear distortions KK and CD in the signal level function, , that in the analogue recording Kni decreases monotonically with decreasing level, while the digital recording increases, tending to 40% (as the relative size of the "Step" of quantization increases). And if the analog recording in the distortion spectrum is dominated by not very cutting hearing 3 ... 5 harmonics, then the digital case is much worse than the combinational components do not form a harmonic series habitual for hearing and their effect becomes clearly noticeable even at levels of about 1%. It is easy to verify that at signal levels of the order of -50 dB and below, CD distortion passes the threshold of permissible 1%.
That is, from below, the dynamic range of the CD is limited not by quantization noise, but by nonlinear distortion. And out of 97.8 theoretical dB, only 50 dB remains. But that is not all! When KK is overloaded, the nonlinear distortions are proportional to the square of the recording level (with an increase in the level of 2 times the harmonic coefficient increases only 4 times) and therefore their short-term increase on the signal peaks is imperceptible by ear. At CDs, when the nominal input level of the analog-to-digital converter (ADC) is exceeded by only 2 ... 3dB, the nonlinear distortions increase tens of thousands of times, so in real equipment digital recording for nominal takes a level of 12 ... 15dB (i.e. to the peak of the real musical signal) is less than the limiting input for the ADC. As a result, only 35 ... 37dB of real is left from the initial 97.8dB, which is 20dB LESS than KK. That is why, despite the subjective absence of "Spike", many phonograms reproduced from CD lead to quick fatigue and have a noticeably worse "depth of stereopanorama" than the same phonogram reproduced from analog vinyl records (modern records made with Direct Metal technology Mastering is highly appreciated by audiophiles and provides a dynamic range of 60 ... 65 dB) or a quality KK.

One can not help but mention two more "Hits" on KK - from the digital compact cassette DCC and the MD mini disc. Since the introduction of DCC (1989) and MD (1993), Philips, the developer of DCC, has been trying to convince audiophiles that it will completely replace KK in 1-2 years. With a similar statement, but already in relation to MD, there was also Sony - developer MD. But ... time passed, and KK is still the prevailing household media of audio programs with the ability to record.
Moreover, if in the beginning the DCC format was supported by the global giant Matsushita and a number of other well-known companies, today DCC produces only Philips, and even a few models (against the background of dozens of KK models). Sony, also dejected by the subjective evaluation of the sound quality, conducted by the German magazine "Audio", as a result of which MD was ranked last with 45 points out of 100 after dividing 1-2 places of CD player (85 points) and KK-tape recorder (85 points), and those who took the 3-4 places in the turntable of vinyl records (80 points) and DCC (80 points), began feverishly improving the system of compression of digital audio data, as a result of which 4 (!) versions of the ATRAC compression algorithm
1- ATRAC 4.5. It's time to remember that 16-bit level quantization is used in DCC and MD, as well as in CD, but in order to reduce the flow of data recorded on the medium, digital compression using algorithms PASC (Precision Adaptive Subband Coding) and ATRAC (Adaptive Trapsform Acoustic Coding), reducing the flow of digital data from 2 Mbit / s to 384 kbit / s and 300 kbit / s, i.e. and DCC, and MD fundamentally less accurately reproduce the sound than the CD. The forecast is a thankful business, but for the sake of justice, let's recall the fate of another (theoretically superior in quality CD) format R-DAT, which at the time of its appearance in 1987, also projected the place of the heir of KK. Indicative in this sense is a fairly accurate prediction of the author of these lines, published in "Radio radio 89". While almost all foreign and domestic press wrote that by 1991 R-DAT completely replaced KK, it was, perhaps, the only publication in which R-DAT was assigned a modest place, except in semiprofessional recording studios (p.175 "Radio radio 89").
Another "audiomif", which I would like to "debunk" in this article, relates to the highly respected and world-famous firm Oolby. Here I must say that Ray Milton Dolby is my idol, and all his activities are a worthy example of engineering skill. But ... and there are spots on the sun, there are serious drawbacks in Dolby systems.
Compared to its predecessors - dynamic filters that work only on playback - Dolby compilers are certainly a huge step forward, because working "Mirror" in the recording and playback modes, they theoretically have to ensure the identity of the duplicated playback signal to the original one. But many "Rumors" note that Dolby still noticeably breaks the spatial saturation of sound, and so-called "purists" prefer to put up with the thorn of the magnetic tape, just to not "chew" the sound with the inclusion of Dolby. There are numerous statements of hundreds of cassette tape recorders equipped with Dolby B, Dolby C, Dolby S systems that allowed me to establish the main reason for these drawbacks: the inadequacy of the magnetic recording / reproducing channels (KMZV) of real tape recorders.
The fact is that the Dolby company has a so-called. "Bilinear" compression-expansion characteristic, at which there are several characteristic fracture points, and for the ideal restoration of the hedgehog signal, the compressor's point-of-merge in the recording mode and the expander in the make-work mode must coincide. In practice, this means that the transmission coefficient of the LMC should be exactly one (or 0dB). The actual tape recorders are not ideally adjusted at all and the compression-expansion characteristics are "shifted", as a result of which a "pit" or "hump" appears on the total amplitude-amplitude characteristic, and at the most inappropriate segment of the recording levels from -30 to -10 dB, responsible for the correct transmission of the reverb "tails" of a musical signal. In the case of the "pit", these "tails" simply disappear, and in the case of the "hump" dynamically protrude, hence the loss of spatial saturation.
There is another drawback in Dolby systems - even with linear AFC of KMZV, the difference in its transmission factor from 1 leads to a dynamic disruption of the instantaneous frequency response, and especially to the PFC, which also violates the naturalness of the sound, "smearing" the stereopanoram into one or the other channel. The reason - in the use of the so-called. filtering technology sliding band - "sliding strip", well masking the modulation noise, but, unfortunately, while the frequency response and PFC strongly depend on the signal level.
Here I would like to note that out of more than a dozen types of compander-type noise suppressors (Dolby B, Dolby C, Dolby S, High Com, Higx Cell 2, ANRS, SuperANRS, AORES, USMA, dbx, etc.) to the "imperfections" of real CMVs was not widely distributed in household tape recorders (mainly due to the successful promotion of Oolby systems in this market), but one of the most well-known in the professional technology compander dbx of the American company DBX (David Blatskter eXcellence), lnc. This compander has two unique properties - a deciline (linear in decibel scale) compression-expansion characteristic and independence of amplitude-frequency characteristic and PFC from the signal level.
As a result, the non-unity of the transmission coefficient of a real CMV does not violate the linearity of the total amplitude characteristic (only the average volume changes, which is easily compensated by the usual volume control), and instant AFC and PFC remain intact (namely, they are responsible for the accuracy of the music panorama playback). Among the undoubted merits of dbx are also high noise reduction efficiency (up to 35 ... 40 dB versus 10 - 20 - 24 dB for Dolby В-С-S), and not only on high ("SHIP"), but also on medium and low (network background, flicker-noise tape and amplifiers, low-frequency transient interference from the adjacent track zap and si) frequencies. As the experts say, "Dolby subjectively reduces noise, and dbx completely removes them." In Fig. 5 for comparison, the spectrograms of the noise of a cassette tape recorder without noise-suppression and with the noise suppressors turned on are graphically depicted. Anticipating the question about the circuitry of dbx, I note at once that the "native" dbx scheme is quite complex and requires the use of several specialized ICs sold only under license DB, lnc.
But for me in recent years, based on the algorithm of dbx, it was possible to create a dbx-compatible compander, called the Universal Compander. Stereovaraint UNIKOMPa 7 comprises non-deficient domestic circuits and provides any bobbin or cassette recorder dynamic range twice (at decibels) greater KMZV own dynamic range. Those. if the actual tape provides 40 dB, with 80 dB will UNIKOMPom if 45 dB, with 90 UNIKOMPom will etc. Unfortunately, the scope of this article does not allow us to dwell in more detail on the algorithms and circuitry dbx + UNIKOMPa, but I am interested to inform that the description and the UNIKOMP scheme are planned for publication in Radiohobby.

 

Cu alte cuvinte ne arata 2 poze, una cu o spectrograma scoasa chipurile cu un echipament AP(Audio Precision) dar fara sa dea date despre ce DAC vorbeste, unde anume a masurat. Apoi mai compara si cu o caseta digitala, cu minidisc-ul si putina istorie a ceea ce inseamna Dolby.

Cam subtire exemplul asta....

[sesebe]

Dacă traducerea reprezinta toată explicația, atunci nu prea valorează nimic, e numai abureala.

Cine a lucrat cu analizoare spectrale știe ca rezultatul depinde forte mult de felul cum setezi aparatul. Nu se dau nici un fel de informații despre aceste setări deci.....

Mai era o chestie care mi-a atras atentia: la semnal de - 50db și chiar mai mic distorsiunile sint sau trec de 1%. O SITUAȚIE FOARTE NORMALA pt ca 1% corespunde la 40db iar dacă scazi din 96db cit are Cd-ul 50db îți ramine 40db adică exact 1% în procente.

 

Numai abureli realizate exact în genul aburelilor audiofile. Dacă găsesc ceva scris într-un articol, nu iau nimic de bun pina nu analizez eu informațiile și demonstrațiile din acel articol - indiferent cine a scris articolul. Dacă nu reușesc insist, și caut informații suplimentare pe subiect pina înțeleg exact ce se intimpla.

Sa te arunci cu capul înainte și sa iei de buna orice informație primita este cel mai rău lucru posibil și se vede și în viata socio-politica din RO.

[hpavictor]

E un punct de vedere relativ , fiecare apreciază ce și cum poate .

[dark_angel]

Nu e tradus tot articolul, am tradus ce mi s-a parut relevant dpvd al CD-ului, in rest explica diferente intre conectori auriti, cabluri scumpe si sunetul lampa vs. trz, din ce am inteles (pe diagonala). Iar figura 3 cu sigla AP nici macar nu este iesirea vreunui DAC, ci a unui amplificator cu tuburi sa arate ca are si armonici de ordin superior nu numai primele 2-3....

[sesebe]

Nu e tradus tot articolul, am tradus ce mi s-a parut relevant dpvd al CD-ului, in rest explica diferente intre conectori auriti, cabluri scumpe si sunetul lampa vs. trz, din ce am inteles (pe diagonala). Iar figura 3 cu sigla AP nici macar nu este iesirea vreunui DAC, ci a unui amplificator cu tuburi sa arate ca are si armonici de ordin superior nu numai primele 2-3....

Pai dece nu ai spus despre asta de la început ca nu mai pierdeam timpul citind și încercând sa înțeleg ce vrea sa spună acolo. Este vorba clar despre audiofili și poveștile lor nemuritoare.

Nu-i zona mea de interes!

[dark_angel]

"Pozna" asta (preluata de aici) a lui tda1541 o fi prea rusinoasa pt. iubitorii de vinyl si/sau casete?

 

Nu stiu ce cd-player rusesc cu DAC08 o fi testat rusul nostru dar daca o fi fost vreun Philips nu trebuia macar sa aiba aliura celei de mai sus?

In loc sa lase un grafic logaritmic si pe verticala rusul nostru a cam dat-o la intors punand pe verticala niscaiva distorsiuni si s-a cam oprit la 0.06% ca altfel ii iesea din ecran ... Nu vi se pare cel putin ciudat?