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Building a home cinema?

Heres [some of] what you need to know:

Home cinema's are sometimes seen as the ultimate urban status symbol. Ideally this space has everything going for it: little natural light, away from the rest of the family's activities, and likely a space that gives you studs and cement to play with. It is also generally accepted that building a dedicated home cinema can raise the potential market value of your home - just like a gourmet kitchen... Consider it as more than entertainment - consider it as an investment.

First Things First

What do you need to think about when you're building a home cinema? First, how big will this room be? Determine the number of people you anticipate using the room for movies most of the time. If this is about to become THE Sunday football destination, you want everyone to be comfortable, right?

Next, What Feeling Do You Want Your Room To Create?

In my experience, this is an excellent place to involve the ‘CFO' of your home. Decide if this is going to be an intimate room for getting lost in movies, or the multi-purpose gaming, movies and music centre of your home. (In the industry, we call this the media room). Decide this with whoever will be using the room so you can create an experience everyone will enjoy.

With that vision in place, you can start laying out the budget. Here's a guide that I recommend:

  • 35 to 40% of the equipment budget to the 5.1-channel home theatre speaker system. Upgrade to 7.1 if you want if you have a large room with tiered seating.


  • 30% to 35% for the high definition video display (rear projection, or front projector and screen, flat-panel plasma or LCD, plus associated controls)


  • 20% to 30% for the electronics (AV receiver or AV processor and amplifiers, Blu-ray player)


  • 5% to 10% for cables, wiring, and miscellaneous materials


  • Labour for installation and system calibration will be dependant on your unique requirements

Choose the Correct Room Shape

Where possible, avoid square rooms and long narrow rectangular rooms because deep bass sound waves misbehave or "pile up" in square or extra-long rooms. They produce "standing waves," which result in areas with bass peaks where you'll hear way too much bass, and "nulls," where you'll hear virtually no deep bass. Sometimes these areas of too much or too little bass will vary every 30-40cm.

*This is where an investment in a design for your rooms layout for seating placement, screen size, speaker and subwoofer choices and their placement is money wisely invested...depending on the complexity of design required a typical design ranges from a few hundred dollars to a few thousand dollars...

Trying to fix the standing-wave problem after the fact using electronic band-aids like equalization or an AV receiver's auto-EQ program, regardless of claims, is virtually impossible.

Instead, opt for a rectangular shaped room where the dimensions (length, width and height) are not evenly divisible by a common denominator. For example, don't choose a room 8 x 4 x 2.4 m.; instead lay out dimensions of 7.5 x 4.3 x 2.4 m. That way, you'll minimize standing waves and the investment required to minimise their impact on your rooms sound quality and therefore enjoyment.

Keep the Room Size to Practical Limits

How many viewers do you expect to have? Figure out how many seats and what sort of seating you'll need - several rows of real theatre-type seats or a couple of couches plus some recliners? Then choose a room that accommodates the furniture and provides a reasonable viewing distance versus your preferred screen size [see note below]. Note that the larger you make your home theatre, the larger the speakers and more subwoofers you'll require, as well as having to investment more for bigger amplifiers.

Allot 50% or More of Your Budget to Speakers and Amplification

Don't blow your home theatre budget on a super-expensive video projector, screen and furniture, leaving little for home theatre speakers and amplification. In other words, match your high-definition visual image with a similarly high-quality soundscape from a fine home cinema surround sound system, otherwise you'll only be disappointed at the jarring disconnect of combining a brilliant picture with inadequate sound. If you invest $4000 on an HD front projection system, then consider spending the same amount on a 5.1-channel home theatre speaker setup and another $1200 to $2,000 or more (depending on the room size) on an A/V surround receiver or double that for a more flexible A/V processor and matching amplifiers.

Compute the Screen Size and Viewing Distance

Your seating distance versus screen size will determine your sense of picture clarity and detail as well as the quality of the viewing experience.

If you choose front projection, go to www.projectorcentral.com and use the Home Projector Calculator to figure out the desirable "throw" distance vs. zoom ranges for specific front projectors at various price points. Remember that standard DVDs are only 480i or 480p and no amount of "up-conversion" will magically turn them into high definition. They are NOT high definition, so you must have a reasonable viewing distance to get satisfying image clarity. You can sit much closer for true high definition TV images (720p, 1080i) or those from Blu-ray players (1080p), as close as twice the screen height measurement. If you watch a lot of standard broadcast TV (not HD), then figure on a seating distance at least three or four times the screen height for acceptable image clarity.

*Most screen manufacturers recommend a minimum of 2 times the screen height to a maximum of 6 times the height...THX specification recommends 3.68 times the height as an ideal seating distance.

Can You Live With Front Projection?

Can you live without front projection!?

A big theatre-like widescreen image has terrific impact, but using a front projector requires a dark room (and I mean totally dark) or the projected image can look washed out. Ambient room light falling on the screen will cause poor blacks and loss of shadow detail. If you are willing to arrange your room so that it can be totally darkened - not too hard in most dedicated home cinemas - then a compact DLP or LCD front projector is affordable and convenient, with quite stunning picture quality. Within limits, a zoom lens lets you adjust the image size to suit the viewing distance and fit the screen. If there is usually ambient light in the room, or you prefer to watch TV and movies with some lights on, consider a projector with high light output or a large plasma or LCD TV - they offer much brighter, higher contrast images than a low specified/priced projector...but again a Cinema like experience demands a BIG picture.

*Of course you can use your plasma/LCD for daytime viewing and your projector for night time viewing.

Remember to Include the Cost of a Screen for Front Projection

Using the wall for projection purposes is possible with some special and fairly expensive paints manufactured for the purpose, but a dedicated screen will produce much better contrast and image brightness. If you want the screen to be electrically lowered or raised out of sight, budget at least $1,000 - $2,000 for a retractable screen. Manually raised or lowered or fixed screens can be significantly less.

Be sure to experience our ‘Cinemascope' acoustically transparent screen for the ultimate home cinema experience

Plan on gyprock or wood-paneled walls and a timber or carpeted floor

Avoid poured concrete floors and walls, which may cause boomy and exaggerated bass and degraded sound quality. If the floor is concrete, ideally plan on covering it with a wood sub-floor and carpet to provide some absorbency. Likewise, cement-block walls should be covered with studs and gyprock or wood panels.

Isolation of sound, between rooms, has become more easily and cost effectively realised with products from Green Glue and Quietglue products.

Consider Your Room Décor as Acoustical Treatment

If you consider using a normal mix of absorbent and reflective surfaces--upholstered furniture, carpet or rugs, perhaps some draperies--and some variation in wall surfaces, then you shouldn't need to budget for room "treatments" or absorbers for your home cinema room, unless there are unusual factors at play (walls of glass, inflexible interior design rigidity). Bookcases or similar furniture will do nicely to prevent hard, aggressive reflections that may diminish sound quality. A room that has too many hard surfaces and is too reflective may inhibit dialog clarity and cause some occasional harshness in the treble; one that is too absorbent may diminish the natural sense of spaciousness that speakers can yield when there are some natural side-wall reflections.

As a general rule, factor 25% surface treatment for absorption and 25% for diffusion.

The goal is to achieve a frequency balance in your room...easier said than done, but worth every effort involved!

Again, be sure to experience our showroom dedicated cinema with it's acoustic treatment to fully appreciate the impact it has on your enjoyment of music, HDTV, games and movies.

Don't Hide Floorstanding or Bookshelf Speakers Inside Custom Cabinets

Speakers already have their own enclosures (cabinets), and are carefully engineered to perform at their best in a freestanding location, unencumbered by special custom cabinets, nooks, custom shelving, or concealed in elaborately constructed cubbyholes behind special grilles. Without following specific design criteria and acoustic treatment this extra cabinetry will degrade and change the neutral transparent tonal balance of the speakers. At the least, deep bass performance will be boomy or hollow-sounding, and the midrange and treble tonal balance may become noticeably nasal or muddy and congested.

And, resist the Urge to Use In-Ceiling Speakers!

The next time you are in a surround sound cinema, look up at the ceiling. There are no surround speakers on the ceiling. Instead, the surround speakers line each side wall of the theatre (plus a couple of extra surrounds on the rear wall).

There are several reasons for this. The first is that Dolby and dts 5.1-channel movie soundtracks are mixed with the surround speakers to each side because human hearing is extra-sensitive to sounds arriving from each side and in front of us (that's why our external ear structures are cupped to collect and focus lateral and front-arriving sound). The effects of surround envelopment and directional cues are much more profound and convincing coming from the side. Our hearing is not as sensitive to spatial cues and sounds arriving from overhead and behind us.

If you want to duplicate the cinema experience and hear the surround soundtrack the way the director and audio engineers intended, put your surround speakers on the side and rear walls of your home cinema. Furthermore, multichannel music recordings played with surround speakers are also more convincing with side-mounted surrounds. It's the delay of the lateral-arriving reflected sounds that tell our ears and brain the "size" of the acoustic space we are in, so placing your surround speakers to each side, above ear level about 1.6-1.8 m or so off the floor will best duplicate how we hear ambience in real performance spaces.

There you have it! A few simple rules to help you make your home cinema all you want it to be for you, your family and guests.

Of-course compromises can, or sometimes, have to be made...knowing which compromises to make is the key to the successful outcome for your home and budget.

And the sales pitch?

Superior products, experience, knowledge, and the results of it's application, is what you have on your side when you engage Mcleans to be your home cinema provider.

To contact Bill Mclean call 1300 995 448

sales@mcleans.info


 

 

Home Cinema Display Calibration

Calibrating the display device in your Home Theatre system optimises your equipment to provide the highest possible level of performance and return on your investment.

 

Why Calibrate?

Display devices in Home Theatre Systems are the last link in a carefully managed chain that begins on a Movie Set or TV Production studio. Directors and Cinematographers spend millions getting the ‘look' just right for their final content. Fortunately Movie and TV Production is engineered to standards for Chromaticity,Colour Temperature and Gamma. Unfortunately most consumer displays do not reproduce these standards well without individual adjustment to account for manufacturing variations and the characteristics of your source equipment.

Calibrating a display to these standards ensures you see exactly what the director intended. A calibrated display appears natural, lifelike and is ‘easy' to view. Most significantly, the natural appearance greatly improves the immersion effect that you strive for when purchasing a display for your Home Theatre System.
 
 

How is the Display Calibrated?

Display calibration requires specialised equipment. Using the highly regarded Milori Colorfacts Professional system teamed with the GretagMacbeth Spectroradiometer. The spectroradiometer is unique in this field as it is able to accurately calibrate displays of any technology. The instrument is designed for both direct measurements from the screen of a display or reflected light from a projector screen.

The basic process for display calibration involves the use of a colour sensor to measure directly from the screen of your display. Various Test Patterns are then shown on the display and adjustments are made in the User and Service Menus to adjust your display to match industry standards and provide the highest level of performance within the capabilities of your display. At the completion of the calibration, a report is created recording the final values and measured performance for your reference.

Calibration can also include adjustments to the focus, convergence, black level, gamma characteristics and other factors depending on the type of display.

Calibrations are performed by an experienced Imaging Science Foundation (ISF) Certified calibrator who is also an Electronic Engineer who understands the technology behind your display.
 

Benefits

  • Natural and lifelike image with accurate skin tones

  • Optimised Black level and Contrast Ratio

  • Reduced banding and noise in image

  • Longer life for Plasma, and CRT displays due to correct drive of the phosphors

  • Improved focus and Convergence for a sharper image

 

Contact Bill Mclean

sales@mcleans.info

1300 995 448

Hi-Fi - Tubes: Terms & Types

Analog playback has had a resurgence, here is some information about Tubes:

Tube Terms and Types
Because tube-based electronics are also part of analog's comeback, you may need to be familiar with the terms used to describe tube amplifiers and their performance. Here is a summary of some popular tube types and term from Cary Audio:

12AU7: a miniature nine-pin medium-gain dual triode vacuum tube. The 12AU7 is popular in hi-fi vacuum tube audio as a low noise line amplifier, driver and phase-inverter used in vacuum tube push-pull amplifier circuits.

12AX7: a miniature dual triode vacuum tube with high voltage gain. The 12AX7 was originally intended as replacement for the 6SL7 family of dual-triode amplifier tubes for audio applications. The tube is praised for its distinctive sound, and its wide use in guitar amplifiers has caused it to be one of the very few small-signal vacuum tubes to continue in production since it was introduced. The 12AX7 vacuum tube is used extensively in preamplifier circuits.

EL84: Sometimes called the 6BQ5, the EL84 is a vacuum tube of the power pentode type. It has a nine-pin miniature base and is found mainly in the output stages of amplification circuits, most commonly in guitar and stereo amplifiers.


EL34: The EL34 (6CA7) is a vacuum tube of the power pentode type. It has an octal base and it is found mainly in the final output stages of an amplification circuit. The EL34 was widely used in higher-powered audio amplifiers of the 1960s and 1970s, and it continues to be very popular in vacuum tube hi-fi products today, including many Marshall guitar amplifiers because of its greater distortion (considered desirable in this application) at lower power than other octal tubes such as 6L6, KT88 or 6550.

6L6: This tube is the designator for a vacuum tube introduced by RCA in 1936. At the time Philips had already developed and patented power pentode designs, which were fast replacing power triodes due to their greater efficiency. The beam tetrode design of the 6L6 allowed RCA to circumvent Philips' pentode patent. Further testimony for this vacuum tube's success would be even simpler: the 6L6GC version is still being manufactured and is used in guitar amplifiers, which makes the 6L6 one of the oldest tubes in the category.

6V6: The 6V6 is the designator for a vacuum tube introduced by RCA in late 1937. The 6V6 is a beam-power tetrode that is similar to its predecessor the 6L6. In the world of consumer electronics applications, the 6L6 was not suitable for consumer amplification because it required a lot of input power, which means it needs a robust power supply. With the introduction of the lower-powered 6V6, which required only half the power of the 6L6, the beam-power tetrode became a usable technology for consumer electronics companies.

300B: The 300B is a directly heated power triode using a four-pin base. The 300B was introduced in the late 1930s to amplify telephone signals. In the 1980s the use of 300Bs by audiophiles had grown. The 300B has high linearity, low noise and good reliability. It is often used in single-ended triode (SET) audio amplifiers. These SET amplifiers output is approximately eight watts, while a push-pull pair of 300Bs can output about 20 watts. The 300B is a musical tube that produces a natural harmonic structure with low noise, and a realistic sound.

KT88: The KT88 fits a standard eight-pin octal socket and has similar pin-out and applications to 6L6 and EL34 tubes. Technically, the KT88 has similar ratings to the 6550 which was designed for use as a servo amplifier. It is one of the largest tubes in its class and can handle significantly higher plate voltages than similar tubes; up to 800 volts. A KT88 push-pull pair in class AB1 fixed bias is capable of 100 watts of output with about 2.5 percent total harmonic distortion or up to about 50 watts at low distortion in home stereo applications. It has a clean and tight, punchy sound.

2A3: To true tube fans, the single-ended triode (SET) power amplifier and the 2A3 triode tube are the equivalent of Megan Fox. Many believe it has the best balance; a combination of audio charm and power compared to other power triodes. While power amps that use the 2A3 were rare just a few years ago, they are now plentiful.

Single-Ended Triode: A single-ended triode uses a single triode to produce an output. It is generally designed to operate in Class A, and many consider SET products to be classic because of their. Simplistic circuit designs.

Push-Pull: In a push-pull amplifier, engineers connect the power supply to the center-tap of the transformer, and a vacuum tube is connected to both the upper and lower end of the center-tapped primary circuit. This configuration allows the tubes to run on alternate cycles of the input waveform. A push-pull design requires at least two tubes to operate and most designs are run in Class AB for power and efficiency.

Triode: An electronic amplification device that contains three active electrodes. The term is usually applied to a tube with three elements: the filament or cathode, the grid, and the plate or anode.

Pentode: An electronic product that uses five active electrodes. The term most commonly used to describe a three-grid vacuum tube. One of the most popular pentode vacuum tubes is the EL34.

Ultra-Linear: A type of electronic circuit that is used in tandem with a four-element tube (tetrode) or pentode tube to a speaker. Audiophiles like ultra-linear operation because of its lower output impedance and distortion levels. Engineers can utilize an ultra-linear design with push-pull or single-ended amplifier concepts.

NOS: New old stock (NOS) is used to describe tubes that were manufactured decades ago, but never used. These vacuum tubes are no longer manufactured by companies under brands like RCA, GE, Sylvania, but they are coveted by tube enthusiasts.

Tube Rolling: When a person decides to change the sound of a tube amplifier by switching vacuum tubes to a different type/version. The idea behind the concept is that each different tube type has a different electrical characteristic and that by testing various tube types, you will find the Holy Grail of audio. Tube enthusiasts find the practice of tube rolling fun because of the dramatic and not so dramatic changes it makes to the tone of an amplifier.

Solid State vs. Vacuum Tube Rectifier: A rectifier converts alternating current (AC) to direct current. A vacuum tube rectifier has resistance, and the more current that travels through a tube rectifier, the more the voltage drops. When the voltage drops, the power of the amplifier also drops, which in turn makes a tube rectified amp sound "spongy" in the bottom end. A solid state rectifier has no internal resistance. It has a fixed voltage drop, and when an amplifier needs power at low frequencies, there's no limitation to its power. A solid-state amplifier has more headroom and audio enthusiasts describe their sound as punchy and articulate.