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Filtru ZOBEL stabilizare impedanta boxe

Posted: 20 Nov 2014, 17:07
by mik1976
Buna Seara

A folosit cineva filtru Zobel pentru boxe ?
Ma bate gandul sa imi confectionez asa ceva sau sa cumpar :
OCOS sau ENACOM ( inca ENACOM e un mister la interior)

http://www.6moons.com/audioreviews/ring/ring.html" onclick="window.open(this.href);return false;

OCOS are o rezistenta si un condensator inseriate dupa cate vad.
A construit cineva asa ceva in sistem DIY ?

Numai Bine ( si cat mai multe auditii)

Re: Filtru ZOBEL stabilizare impedanta boxe

Posted: 30 Nov 2014, 08:54
by puf
Din cate stiu eu reteua Zobel se utilizeaza ca un filtru pasiv direct la bornele difuzorului nu a incintei.
Rolul sau era de a compensa frecventa de rezonanta a difuzorului care duce la un raspuns foarte neliniar.
Incintele EI precum Meloman aveau in crossover retea Zobel pe fiecare difuzor.
Acum nu stiu cat de mult ajuta, orice adaugare poate sa aduca un castig la ceva si pierdere la altceva, adica un compromis care poate fi utilizat in functie de preferinte.

Re: Filtru ZOBEL stabilizare impedanta boxe

Posted: 30 Nov 2014, 11:11
by hondaru
Filtrul Zobel are ca scop si prevenirea intrarii in oscilatie a amplifului la frecvente foarte ridicate daca practic acesta este capabil de a reproduce aceste frecvente. Une amplifuri chiar se lauda cu raspuns in frecventa pana la 1 MHz! Producatorul acestor amplificatoare chiar stipuleaza in manual ca se pierde garantia daca nu se folosesc cabluri de boxe cu filtre incorporate. S-a constata practic o ridicare a regimului termic al amplifului in cauza la folosirea cablurilor fara filtru. Firma respectiva produce aparate hi-fi cu mult peste bugetul nostru al muritorilor de rand.
Ei nu au introdus acest filtru in amplificator pe motive de alterare a sunetului dar in schimb il vor montat pe cablu! Cei ce proiecteaza aceste aparate sunt conform declaratiilor oficiale niste ingineri de exceptie ce au la activ colaborari cu NASA deci probabil stiu ei ce stiu!
Daca tu in sistemul tau poti sesiza diferenta in sunet schimban 2 cabluri de boxe este posibil sa poti auzi si diferenta in sunet cu/fara filtrul mentionat, daca nu, ma cam indoiesc ce vei simti ceva la ureche....poate doar in buzunar pe banii cheltuiti cu acest proiect.

Re: Filtru ZOBEL stabilizare impedanta boxe

Posted: 02 Dec 2014, 08:50
by remoteviewer1
Tipul asta Alan de care amintesti tu (dizainaru), este putin ticnit, insa in sens bun pana la urma. El face fara indoiala boxe foarte bune, pe care le am si acasa (sh) insa, exista un mare INSA eu nu sunt de acord cu multe lucruri pe care le spune el referitor la celelalte componente ale sistemului audio, nu ma refer la boxe in domeniul in care pare a fi maestru.

In primul rand, el nu crede in cabluri de niciun fel, afirma raspicat ca totul e marketing si bullshit. In acelasi timp afirma ca toate cd-playere suna la fel si numai fraierii cheltuie bani pe componente scumpe, orice cd-player de la supermarket fiind mai mult decat ok pentru a-i pune boxele in miscare. In ultimul rand (din ce mi-am amintit eu) el crede ca lumea iroseste banii inutil pe amplificatoare scumpe, si chinezariile cu nume englez sunt mai mult decat suficiente pentru boxele lui cu sarcini usoare (aici nu as fi in totalitate de acord cu el, nu mi se par SHL5 niste modele de boxe usoare de dus).

Eu sincer, daca nu as fi avut constrangeri de bani, si as fi citit forumul inainte de achizitionarea boxelor, nu cred ca mai eram client Harbeth, probabil trebuia sa ascult boxele inainte si apoi sa ma conving, deoarece forumul respectiv nu cred ca ma reprezinta mai deloc ca si punct de vedere in general despre sistemele audio.

AAA, sa nu uit bomboana de pe tort, are si un filmulet prezentat pe ytb in care arata diferenta pe osciloscop :lol: :lol: :lol: , dintre semnalul de cd player (ce pare a avea sinusoida perfecta) si cel provenit de la un pick-up analogic (ce pare a fi murdar, plin de artefacte) si conclude glorios: cd-ul este superior vinilului :lol: :lol: :lol: .

Tot ce am scris mai sus, nu schimba cu nimic faptul ca boxele iesite din mana lui sunt bune, insa m-as intreba cum s-ar auzi boxele respective daca roscovanul incapatzanat ar pleca urechea si la audiofili... :?:, asa numai un pic. Tot ce este scris pe internet trebuie sa fie filtrat cu un mare filtru rational, deobicei realitatea e mult diferita...

Re: Filtru ZOBEL stabilizare impedanta boxe

Posted: 02 Dec 2014, 12:29
by momolo
viewtopic.php?f=1&t=13&start=150" onclick="window.open(this.href);return false;
doru wrote:Mai jos, pentru cine are rabdare, se poate citi un comentariu referitor la expozitia de la Munchen, al designer-ului sef de la Harbeth. Mi s-au parut niste aprecieri extrem de interesante, in special asupra boxelor, venite de la un producator de boxe oarecum atipic pentru vremurile de astazi.
La respectiva expozitie de altfel a prezentat si noul model Harbeth, denumit Super HL5 Plus: http://www.harbeth.co.uk/library/pr/May14-Munich.pdf" onclick="window.open(this.href);return false;

Having looked around the vast Munich MOC exhibition halls (up from three to four this year) the visitor is immersed in a complex theatre of scientific fact, self deception and willful marketing BS. Does it matter? Not really: it's all harmless stuff, and neither is it going to extend nor shorten ones life by years, nor make one a better, kinder person. It certainly can make you poorer though and take you further from natural sound, as you would hear in the flesh.

We all know that electro-mechanical loudspeakers, (like their brothers, pickup cartridges) will always have personalities to one degree or another: that's a given. Are those sonic personalities dominant now that we've had 100 years or so to perfect the e-m transducer? Yes and no. It would be wrong for me to meander around as an unpaid critic, castigating other designer's hard won efforts, especially as they seem to have found customers for their products, and I assume those customers are delighted, but one or two overall sonic characteristics struck me from a brief non-scientific tour, as they have done before. I'll share them with you for what its worth, merely to keep at the back of your mind for when auditioning any loudspeakers:
1. As a general observation, some of the biggest, most advertised, most reputed brands make the most colored sounds
2. Horn speakers, with very few exceptions, sound like a megaphone, but there are just one or two so well designed that they sound intriguing
3. Many listeners seem to have, to my mind, a strange interchangeable relationship between soundstage size and soundstage coloration (aka sonic quality). More on this later
4. Big speaker generally produce a bigger soundstage
5. The more drive units covering the midrange, the worse the sound
6. An array of small bass/midrange drive units somehow does not produce the 'weight' of a smaller number of larger diameter drivers
7. Some otherwise well integrated and sweet sounding speakers using interesting and unconventional drive units (in the mid/top) are crying out for more 'warmth' in the lower registers, which if they had, would propel them into greatness
8. Loudspeaker brands that successfully market primarily or exclusively to the pro-audio market (but have ambitions to enter the domestic arena) made some of the most colored, unpleasant, pinched, peaky sounds at the show. They were dreadful
9. Most exhibitors play far too loud
10. Most exhibitors do not select music which shows off the best of the speakers they are demoing
11. There is no positive correlation between price and performance beyond a certain ceiling. A Eur. 100,000 speaker may actually be worse - far worse - sounding than a 10,000 speaker. Of those Eur 100,000 speakers, the beautiful cabinets, the things you are paying and arm and a leg for, actually cost only about 3% of the selling price and the drive units even less
12. Visitors are very influenced by speaker size. Huge loudspeakers big enough to fill a normal room may well produce a mediocre and painfully coloured sound (when they reproduce certain musical notes), but the sheer size of the speakers and the logistic effort and cost to bring them to the show can win over the most analytical, educated, rational and cultured mind (see also 3. above)
13. The public, generally, have a very short audio memory and (seemingly) cannot deconstruct what they hear as they hear it. This is a serious problem, because without being able to hop between demonstrations recalling the key elements of previous exposures, those technicolour sonic experiences collapse into a monochrome ghost memory within seconds. After an hour of demo after demo, everything sounds the same. Maybe? I find that the differences actually become amplified in my mind
14. Styling has zero correlation with sound quality
15. Nobody cares where products or piece parts are manufactured in a global interconnected world
16. There is increasing brand consolidation and the pace of this will doubtless increase
17. I rarely heard classical music
18. All the demo rooms (cabins built for the show) boomed and had a range of coloration issues that made decent demos touch-and-go depending upon the music, how many bodies were in the room to soak up sound and especially, how loud the system was played
19. Sales staff must have become progressively deaf as the day passed, because they compensated by increasing the replay volume
20. Audio-only surround sound has been (sadly) almost forgotten, yet a little rear-channel sound can beneficially open-up the sonic experience on classical music if the speaker characteristic are matched all around the listener
21. Home theatre centre channel is far too 'dark' on the movies I heard, with American actors very close to the microphone
22. HT using flat, natural speakers (like the SHL5plus in the REL room) can sound comprehensively enthralling at the right replay level
23. Most/all 'monitor' type speakers are used on stands that are domestically acceptable but technically too short for the intended best sound (tweeter is way below ear level)
24. Continental speaker designers may (this is gut feel, not fact) design with the reference axis (best drive integration) between the bass/mid and tweeter not on axis with the tweeter. This would mandate a very tall stand for the best sound
25. The more exotic the bass/mid driver cosmetics, the harder and more colored the sound
26. 12" (300mm) drivers only work properly in the midrange and bass. They cannot be expected to produce clean, natural sound in the upper midrange, and they do not. That is wholly predictable by science whatever twaddle the marketing boys come up with
27. The Chinese are making copies of old-style BBC LS series monitors which are (superficially) cosmetically remarkably close to the original 70s/80s models and very inexpensive, devaluing the concept of the BBC licence, which is, anyway, legitimately available to anyone who applies and pays the small fee, irrespective of experience or geographical location
28. There were no new, interesting, cone materials likely to outperform existing materials, and two exhibitors who displayed their so-called new materials last year have disappeared (as I predicted) because we reviewed and dismissed those candidates over twenty years ago
29. As a general comment, whilst many speakers produced bass, very few produced an engaging warmth in the lower registers. Cellos sounded far too much like violas
30. Several non-Harbeth owners commented that their existing speakers just did not integrate properly unless they were seated far from them, too far for convenience. A Harbeth trademark is that regardless of whether you use your Harbeths like headphones (try it - very addictive: huge soundstage!) or in the far field, the sound quality does not change. That is really a defining characteristic of the way we design
31. Visitors who are impressed by large speakers forget that there is no certainty that such will work harmonious in the domestic room
32. It would be unwise to use a brief opportunity to audition a loudspeaker at a trade show under unfamiliar conditions as a substitute for a proper listen at a dealers or at home
33. The contribution of the electronics, cables, stands, room and music in any demo cannot be mentally separated, so drawing conclusions about the speakers alone is risky. Despite this, it is easy to hear visitors comment, upon entering a demo room that the reason the sound is good/bad/ugly is inextricably linked to one element of the equipment chain on demo, typically the cables or mains filter
34. Most contemporary loudspeakers have too much high frequency energy
35. An exhibitor may, with justification, modify his equipment to provide a best possible sound under the far from ideal conditions of a trade show
36. The leakage of sound from competing exhibitors stimulates the fight or flight response: I find that just being in that noisy environment is extremely tiring because of the heightened awareness. I live and work in almost complete silence


I'll add to that list if I think of anything.
Alan A. Shaw
Designer, owner
Harbeth Audio UK

Re: Filtru ZOBEL stabilizare impedanta boxe

Posted: 02 Dec 2014, 13:06
by remoteviewer1
Sunt cu totul de acord cu afirmatiile de mai sus ce se refera la Boxe, insa nu cu (unele) afirmatii cu privire la cabluri, amplificatoare si surse de pe HUG, ce este un forum destul de "inchistat"dupa parerea mea, si e normal sa fie avand in vedere ca e forum de producator de incinte si nu de altceva. Eu am ascultat zeci de amplificatoare si cd-playere si niciunul nu suna la fel, o fi urechile si partea de creier dintre (daca am asa ceva) ele de vina :lol: . Ei se lauda ca vor porni o revolutie pe acolo...In fine, asta nu schimba nimic din faptul ca omul stie ce face si are un succes formidabil, de care sunt beneficiar si eu indirect :mrgreen: .

Re: Filtru ZOBEL stabilizare impedanta boxe

Posted: 02 Dec 2014, 13:47
by momolo
Eu cred ca este cumva situatia ginecologului in relatia cu p_zda la modul general. Cand toata ziua asculti boxe, difuzoare, scule, o iei razna, am mai vazut cazuri. Poate si pentru ca nu-i pasa de cablaraie, amplifuri, playere cd, etc, a reusit boxe bune, poate se chinuie sa le faca sa placa urechilor in conditii vitrege. O fi omul putin dus cu pluta (artistii sunt in general cam toti tzacnitzi) dar ureche are, clar!
Si poate conteaza si cercetarea aia prin care s-a inventat difuzorul ala misto.

Re: Filtru ZOBEL stabilizare impedanta boxe

Posted: 02 Dec 2014, 20:04
by lordu73
Oricum, tipul n-a zis niciodata ca TOATE amplificatoarele suna la fel, ci ca TOATE AMPLIFICATOARELE BINE CONSTRUITE (de bun simt - nu orice chinezarie) suna la fel, si are chiar si un pariu lansat pe tema asta.
La cabluri, are cam acelas soi de comentariu, CABLURI DECENTE dar nu extravagante (a nu se folosi la colorarea sunetului).


Mai zice pe undeva ca analogicul "place" mai mult si pare mai detaliat din cauza dinamicii mai scazute a sunetului.