Avalon Acoustics Isis manuale d’uso

D ESIGNED BY N EIL P ATEL FOR A V A LON A COUSTICS This product is cert ified to meet the requirement s of the European Un ion (EU) Electromagnet ic Compatibility (EM C) Di rective (89/336/EEC ). Because the permanent magnets attached to the loudspeaker drivers produc e magnetic fields, i t is recommended that the p roduct not b e positioned in ver[...]

Table of Contents 1 Introduction ............................................................................................................................ 4 2 Unpacking Instr uctions .......................................................................................................... 5 Introduction ..........................................[...]

9 Accuracy of Bas s Reproduction .......................................................................................... 33 Introduction .......................................................................................................... 33 9.1 Sensitivit y to Time-Relat ed Informati on .....................................................[...]

4 1 Introduction is the most technologic ally adva nced h igh -energy transducer ever created. Our foc used research over a p eriod of four years ha s produced a range of advanc ements in ea ch aspect of loudspeaker perf orman ce. Proprietary conductors and magnetic technologies, as well as new techniq ues in cabinet construct ion, have bee n combi[...]

5 2 Unpacking Instructions Introduction Your A VALON A COUSTICS loudspeakers w ere shippe d in a two heavy- duty c rates to ensure t heir safe arrival. It is rec ommen ded to save these crates for possi ble future use. D ue t o the weight of the speakers, it will req uire two persons t o un -crat e them a nd position them for li stening. Plea se ar[...]

6 2.1 Opening the Crate The crate features a one -pi ece top assembly wh ich is fastened t o the crate bottom wit h screws around the low er perimeter. T o unpack, remove the screws a nd li ft th e upper port ion of the crate st raight up (this w ill require two people). Next, slide each spea ker part way off of the cr ate base so th at the plastic[...]

7 2.2 Installing the Grilles The grille assemblies are behin d a panel on t he outside of the speaker crat e. Remove the screws securing the panel, and then carefully pull the grilles straight out. The gri lles are i nstalled with friction fasteners and p ress int o p lace on the speaker ca binets. Please see Figur e 2.2. Orientation of the F elt A[...]

8 2.3 Replacing Grille Pins The grille pins i nstalled on the gri lle assemblies are fragil e and can be easily damaged. Should a ny of t he p ins break, you may repl ace t hem using t he following p rocedure. 1. Plac e t he gri lle a ssembly face -dow n on a p added surface (a towel or carpetin g). 2. Rem ove the damaged grille pin by pulling it s[...]

9 4. Carefully p ull the grille cloth awa y from the frame mounting hole. The mounting hole must be clear of all obst acles durin g pin inst allation. 5. Place the exposed en d of t he grille pin in the open mounting hole. Che ck to insure that th e grille cloth is not trap ped between the pin and frame. Use a small hammer and gently tap the new gr[...]

10 3 Wiring Instructions Introduction The crossover i s encapsula ted in a sealed, non-acc essible chamber in the bottom of the speaker cabinet, to minimi ze the effec t of vibrat ion on the components . The ISIS is equipped with high-quali ty binding posts for connecting the spea ker cables. Spade l ugs are recommended for ca ble termination s. Co[...]

11 4 Break-in Period Your new A VA LON A COUS TICS loud speakers have an initial b reak- in peri od. They will not perform t o their full sonic p otentia l when first in stalled in your system. This i s pa rtially due to a residual polarization of th e dielectri c mat erials used in the crossover capacitors and internal wiring. 1 As music is played[...]

12 5 Maximizing Performance These details are im perative to obtain ing optimum results from your A VALON A COUSTICS loudspeakers. Break- in The break -in period i s critical t o maxi mizing sonic performanc e and should take place before ot her adjustmen ts (see t he di scussion on page 11 ). T he break-in should begi n w ith t hree t o six hours [...]

13 Toe- In Adjusting the toe -in angle of th e speakers is useful in t ailoring t he sound to best mat ch the characteristic s of your system and li stenin g room. When t he speakers are fac ing stra ight forward, t hey tend to crea te a large, expansive so und-st age, pai nted w ith broad b rush strokes. A s they are rotat ed toward the listening [...]

14 First Reflection Points Since t he ear/b rain system tends to i ntegrate t he sound s arriving w ithin a 10 millisecond time wi ndow, it is important to control the early reflec tions arri ving from t he sidewal ls to th e list ening position. A hard -surfaced wall c an produce a strong frequency-de pendent reflection that can interfere with the[...]

15 6 Care of Your Loudspeakers Cabinet (Hardwood Finis h) A VALON A COUSTICS ’ hardwood finished loudspea kers are supplied w ith a special p olish and two lint - free polishing cloths, in order to properl y care for the h igh qual ity furnit ure lacquer . The foll owing polishing instructions should b e observed: IMPORTANT: Use the sup plied fur[...]

16 7 Warranty Your A VA LON A COUST ICS loudspeakers ar e w arranted to th e origin al, registered purchaser aga inst defec ts in workmanshi p and materials for a peri od of three years from t he date of first purchase, pro vided th at the enclosed r egistration card is returned to the factory within s even days of the purchas e date. If the regist[...]

17 Warranty Statement 1. A VALON A COUSTICS warran ts the materials, workmanship , and proper functioning of thi s product for a period of t hree years to t he origi nal regi stered purchaser, pro vided th at the completed registration card is returned to A VALON A COUSTICS within seven days of the date of pu rchase. If the registrat ion card is no[...]

18 6. The above w arrant y is the sole warran ty gi ven by A VA LON A COUS TI CS , and is in lieu of all other warranti es. A ll impl ied wa rranties, including w arranties of merchanta bility or fitness for an y part icular purpose shall be stric tly limit ed in duration t o t hree years from the date of shi pment from t he factory, and u pon the [...]

19 8 R o o m A c o u s t i c s a n d S p e a k e r P o s i t i o n Introduction The listening room forms the final link of the playback system, as imp ortant as any ot her c omponent in t he chain. Just a s an o therwi se superb system is handicapp ed by an inferior p re -amplifi er (for example ), so can a well-mat ched system be hindered by poor [...]

20 An Optical Analogy Let us use a vi sual a nalogy to aid our underst andi ng of acoustic s. I magine that you are in a room that is lit only by a candl e in its center. There is (approximately) a unifor m amou nt of light c ast in all di rections. I f a large mirror is held closely to candle, one h alf of t he room becomes darken ed, while t he o[...]

21 8.1 Standing Waves The parallel surfaces of most li stenin g rooms can lead t o a potential problem in the low frequencies. A sound wave ca n be repeatedly reflect ed from opposing surfaces, back and forth. If the distance betw een t he surfaces is an integral multiple of one-ha lf the sound wavelen gth, a st anding wave w ill be set up. This me[...]

22 8.2 Flutter Echo These parallel, reflect ive surfaces can also produce a different audi ble problem. If th ere is l ittle a bsorption at high er frequencies, a m usical transient containin g high frequencies, such as a hand clap or t he strike of a percussion instrument, ca n be heard bouncing repeatedly bet ween the surfaces. Called flutter ec [...]

23 8.3 Early Reflections Another sit uation t hat c an reduce t he subject ive qualit y of reprod uced s ound is the presen ce of early reflecti ons. B y earl y reflect ions, w e are ref erring t o reflected sound waves th at reach the listen er with in 10 t o 20 mill iseconds of the direct signa l from the loudspeaker. When a reflected sound reach[...]

24 Avoiding Early Reflecti ons The speed of so und is a pproximat ely one foot (30 cm) per millisecond. Therefore, t o p reserve t he n atural soundstage on your recordings , there should be no reflect ed sounds arriving at the listening positi on w ith a path length l ess than t en feet (3 meters) longer th an the di rect path from speak er to lis[...]

25 Since the floor i s wit hin 5 feet of the speak er, it is b est to have a carpeted fl oor to absorb floor reflect ions. A t hick, den se carp et and pad will absorb lower frequencies more eff ectively tha n a thin one. Due t o their c omplex structure, carpets and p ads of natural material s, such a s wool and jut e, will exhibit a more uniform [...]

26 8.4 Bass reinforcement By bass rei nforcement , w e mea n t he effect of t he room boundarie s on the propagation of sound. It is widely kn own that speaker placement relative to the floor an d walls ca n affect the relative amount of bas s t hat the system produces. To make this in teraction more clear , let us refer t o the opti cal analogy of[...]

27 By pr operly select ing the dist ances to eac h surface, we can extend the in - room bass response of th e speaker much deeper t han it s anechoic response. Please see Fig ure 8.5. This i s because t he bass reinforcement provides a boost which i s complement ary to t he bass roll -off t hat w ould be present in an anechoic chamb er. Figure 8 .4[...]

28 Conversely, improper placement o f the loudspeakers can re sult in une ven frequency re sponse. This results in di minished bass quality. Please refer t o Figure 8.6. As fr equency increases and wavelengt h becomes more similar to t he distance to the boundary, the phase differen ce between origi nal and reflected wa ves in creases, a nd the air[...]

29 There are typicall y three reflect ive surfaces near eac h speak er: the floor, the rear wa ll, and the side w all. Each of th ese surfaces produces its own reflection, and hence its own cancellation an d reinforcement . By properl y selecting the dist ances t o each surface, we can provide a uniform a nd extended bass response. Conversely, impr[...]

30 8.5 Summary of Recommendations Now that we have l ooked at some of the common problems of listening rooms, as well as their cures, let us summarize our findings an d recommendations . Flutter Echo and Standing Waves These situat ions are the result of the r oom having parallel, reflecti ve surfaces . The potent ial probl ems are indep endent of [...]

31 Speaker Placement Although yo ur A VALON A COUST ICS loudspeakers may be placed in a w ide variety of positi ons rel ative to t he walls of the ro om, it is sti ll wise to experiment a bit t o achieve optimal results. The suggested mini mum distances for the I SIS are 3 feet from one wall (side or rear ), and 5 feet from the other ( all dist anc[...]

32 8.6 A Listening Room Example In order to make these points more c lear, an example of a room l ayout is given in Figure 8 .9, illustrat ing the prin ciples we have given. Figure 8 .9 - Examp le listening room. The area ar ound th e spea kers is free o f o bjects that would produce ea rly reflect ions. A tapestry is hung opposite t he draperi es [...]

33 9 Accuracy of Bass Reproduction Introduction We have all ha d the experienc e of list ening to spea kers w ith poor bass quality. Perhaps th e ba ss was muddy, or ill- defined. Possibly the b ass was exaggerated or bl oated. In any case , th ese type of distorti ons ar e distracting and can keep us fr om en joying the full meas ure of t he perfo[...]

34 9.1 Sensitivity to Time-Related Information It is wi dely known t hat the human ear/b rain system is ext remely sensit ive to time-rel ated distortions. This can be understood when one reali zes that directional a nd spatial information is provided by in ter - aural ti me (and phase) differences. During t he period of man's evolution, t he [...]

35 9.2 Rationale There i s an old sayin g, " There's no such th ing as a free l unch." There are many trade-offs in spea ker design, as in almost any ar ea one can th ink of. I n t his case, th e tra de off is b etween transient response and anech oic frequency response (the speaker 's frequenc y response in an anech oic chamber[...]

36 9.3 Measurements of Audio Equipment It should be recognized that mea surements are not th e final arbit er of sound quality of audio comp onents. Oft en ti mes a measuremen t st andard has evolved because i t is easil y perf ormed, or bec ause it is easily rep eatable, or it has shown some lin k to certa in audible characteristics. Unquestionab [...]

37 Loudspeaker Measur ements Returning to loudspeakers , a similar situation has developed. Although nobody listens t o music in an a n echoic chamber, l oudspeaker meas urement s are commonly p erformed in them. 3 Although various proposals h ave be en made for performing low frequency meas urement s in a more realistic setting, there has been no [...]

38 Designing for Accur ate Bass Reproduction How, t hen, does one arrive at the goal of a loudspeaker tha t p rovides tonal accuracy in the listeni ng room? The an swer, i n la rge part , comes in t he f orm of th e digi tal computer . It is possible to creat e a mat hematical model of a listening room, and predi ct the response of a give n spea ke[...]

39 9.4 Listening Qualities We have s een how many speaker systems store re sonant bass energy , resulting in ringing and poor transien t accuracy. N ow we w ill turn our attention to the listening experien ce, an d describe how th ese measurable properties correlat e with our subjecti ve impressions. There are tw o main factors w hich affect subjec[...]

40 Transient Response E ffects A speaker with poor transient response w ill store energy, rel easing it aft er the initial musical t ransient has passed . This ca uses a loss of det ail and obscures important musical informati on. A l so associated w ith poor t ransient response is a narrow- band resonance, whic h can empha size specific notes. Whe[...]

41 9.5 Important ISIS Recommendations Built as an ident ical p air of transducers, ISI S ret ains one di fference between right and left c hannels that is notew orthy. Very low freq uency bass coupl ing with the room is selecta ble in one of tw o orientations. Even serial num bers should be pla ced as the left chan nel, wh ile odd serial numbers ar[...]

42 10 Features  Advanced light w eight driver diaphragm materials minimize energy storage and time -domain dist ortion.  Each driver in dividually tested and m atched for op timum performance .  Smooth, wide polar resp onse for superl ative ima ging capab ilities.  Moderate impedanc e ch aracteristic allows for ideal interface wit h any[...]

43 11 Specifications Driver Complement 1" Concave Diamond D iaph ragm tweet er 7" Concave Cerami c Midrange 2-13" Nomex-Kevl ar Composit e Woofers All drivers uti lize propriet ary neodymium ma gnetic technologies. Sensitivity 90 dB Impedance 4 ohms nominal Frequency Response 20Hz to 45kHz Recommended Amplifier Power 75 to 750 w atts[...]

44 12 Notes[...]