HOME THEATER CALIBRATION - FREQUENTLY ASKED QUESTIONS

1. Why would my display need calibration?

2. Why would I need an audio calibration?

3. Why would I need design or consulting services?

4. Why choose AccuCal?

5. Please explain the calibration process.

6. What should I spend on cables?

7. Do I need a UPS or a surge protector?

8. What type of connection (cable) should I use?

9. Reference Quality Blu-Rays

1. Why would my display need calibration/setup?

Connecting displays properly can make a huge difference in picture performance.  Each setup will confirm or fix the connections used (cost of cables is separate).

Displays are shipped from the manufacturer with the colors set to sell on the showroom floor.  It is for this reason that most displays are not setup correctly from the factory. 

The color errors found in many displays are 20 to 40 percent excess in blue and 20 to 40 percent deficient in red and green.  They also frequently add something called edge enhancement to the picture that distorts the image and loses resolution.  Many displays also have too little or too much contrast in the image because the picture is too bright or too dark.  This will make the image look either washed out or cartoonish. 

In addition to this the DVD players, cable boxes and satellite receivers all have settings in them that effect the picture quality and may not output signals that match the standard levels. They also have various types of video connections many of which will not deliver the highest quality image. 

The display calibration process will reduce these errors along with others found in both the display and the source resulting in an image that will more closely match the original image giving you the highest quality picture that your equipment is capable of delivering.

The following is a comparison of typical pre and post calibration color performance.  These errors will cause the picture to look less realistic.  Excellent color performance is critical for a home theater experience that draws you into the experience.

The following is a comparison of the light output performance of a typical display before and after calibration.  These errors will cause a display to look washed out or cartoonish.

2. Why would I need an audio calibration?

Connecting audio equipment properly can make a huge difference in sound performance.  Each setup will confirm or fix the connections used (cost of cables is separate).

Surround sound systems found in most home theaters are very complex systems that attempt to recreate the sound environment found in a commercial theater or a music performance.  They do this by using multiple speakers that are placed around the listening environment.  These speakers are then used in concert to reproduce a multi-dimensional sound experience.  When done properly the home system can be as good or better than the theater.  Unfortunately, when things are setup poorly, which is generally the case, the surround sound experience is not very satisfying. 

Executing this well requires that each speaker blends in convincingly and is positioned reasonably with respect to the other speakers and the listener.  This requires careful placement of the speakers and proper adjustment of the various settings in the receiver or processor being used.  The settings that can be found there include things like time delays, speaker levels, speaker size, tone controls, equalization and subwoofer crossover frequency.  Without quality tools getting these anywhere close to correct is next to impossible for most people. 

The following is an example from a clients home.  The first graph is the average frequency response of a 5.1 surround system that was installed by "professional" installers who used the automatic setup feature found in a popular brand of receivers to complete the job.  The goal here is to have a frequency response that is generally smooth with some tapering of the high frequency response above 2k Hz.

In this case the client was very dissatisfied with his sound quality.  The system did not sound very high quality although he had spent a considerable amount of money.  It was also difficult to understand the dialogue.  Looking at the frequency response it is easy to see why this was the case.  The installers suggested solution to this problem was a more expensive brand of speakers.  The following solution required no equipment purchase.

Properly calibrating this system with quality test material and professional equipment resulted in the following average frequency response.  Note that the high frequency performance is greatly improved. 

This chart alone does not show all of the improvements that occurred, but it is a good indication of how dramatic the improvement was.  The system went from a very poor level of performance to a very convincing surround sound experience that delivered the full level of performance from the equipment that had been purchased.  The client was also given advice on what changes could be made that would give real improvements in sound performance if desired.

Without a detailed and thorough audio calibration using a quality microphone and sophisticated tools your system is likely to be delivering results that are far less than they could be no matter how much or how little was spent on the equipment.  Many people who are dissatisfied with their surround sound continue to change equipment when the real answer can frequently be found within the equipment they own if only they had it setup correctly. 

Expert advice along with detailed measurements can pinpoint where a system could be improved when that is a goal.  These improvements may consist of many things, but suggestions can include modifying the room furnishings, altering the placement of some speakers or adding/replacing some equipment.  Unless someone skilled in the art visits your home and then measures and listens to your system it is impossible to give accurate advice on how your system can be improved.

Download a presentation on my perspectives about audio by clicking here.

3. Why would I need design or consulting services?

These services will address your purchase and installation considerations.  The equipment you choose and how it is installed will limit your performance and determine your cost.  Things that we can help with include:

• Room Acoustics

• Speaker Positioning

• Listener Positioning

• Audio and Video Equipment Selection

• Minimizing Installed Cost

• Maximizing Performance

We will work with you to determine the best products and solutions that fit your needs.

Examples of room acoustics design results follow:

4. Why choose AccuCal?

The primary reason to use AccuCal versus others is the certainty that you will get the best results possible from your equipment.  All ISF and THX calibration services are not of the same quality.  We also offer more services for audio and video than you will find anywhere else in the market.  We do not take jobs where we do not believe the equipment will benefit from this service.  If you have poor gear we cannot make it great.  We also do not charge when we find equipment that cannot deliver reasonable results.  AccuCal is not going to be the fastest or the cheapest, but we do try to be the best.

All of the measurement equipment used are the finest available on the market delivering fabulous consistency and quality.  Quality tools are not inexpensive or common.  We have tested many of the other tools on the market and have found serious problems.  If you calibrate a system with lower quality tools you are going to get poor results.  You have a significant investment in your equipment.  We also have tools that are proprietary and unique to this industry to allow us to achieve superior results.  Why should you not have your system performing at its optimum capability? 

The skill and desire of the person working with your system is also very important to the process.  We treat everyone's system like it is our own and constantly strive to improve our service offering.  We schedule enough time for each job to be certain everything is as good as it can be.  Some of this skill is derived from working with professionals on the equipment and production side of this business.  Some is derived from months of study and experimentation.  The rest is from over 25 years of experience solving technical problems as a degreed engineer.  Because of this many of the tools and techniques used are proprietary to AccuCal.  Doing this right requires not only great tools, but experience and an understanding of what good sound and picture performance is.  If you don't know what you are shooting for you cannot tell what compromises to make.

Here are some words of wisdom on this subject from an expert who I have met and respect:  Brian Vessa, executive director of digital audio mastering at Sony Pictures Entertainment , "SMPTE standards and recommended practices help to minimize variations, but cinema sound quality today is highly dependent on the skill, talent, training, and hearing acuity of the adjusting technician.”  The same could be said for video quality as well.

Our purchase advice is our honest opinion because we do not benefit from these suggestions.  We can help you select the best equipment for your budget and ensure it is performing properly in your home.  Many audio and video products on the market have serious software errors, performance and reliability problems.  Why not let us help you avoid them and benefit from our experience of working with hundreds of different audio and video products a year?

Read the reviews for further proof of the quality of this service.

5. Please explain the calibration process.

This process begins by booking an appointment to visit your home.  A thorough calibration requires between 4 and 8 hours to typically complete depending on the services purchased and the specific equipment to be calibrated.

    Video

The first step is to view actual program material.  This is useful in demonstrating the initial performance and determining where the system may be deficient.

The second step is to review the connections being used and modify the setup if it is not appropriate.

The third step in calibrating video is to take a detailed set of measurements that quantify the initial system performance.  This serves two purposes.  It documents how the system was performing before calibration for later comparison and it highlights where the current system is deficient.

The fourth step is to adjust each input in use on the display so that the picture color, contrast and resolution are the best that they can be.  This is done using trained eyes to verify solutions and spot problems, a spectroradiometer to measure the color and intensity of light and a signal generator to generate test patterns that are used to adjust the display.

The fifth step is an examination of each source (DVD, Satellite...) on the display to verify that it is sending the correct information to the display.  The source or the display is adjusted when any problems are found.  This step requires reference material (Avia Pro...) in the proper format or a signal generator feeding the source to verify the source is properly configured.

The sixth step is a review of actual video or film material to verify that the picture performance meets your expectations.

The final step is to provide a file of the before and after calibration measurements along with a detailed list of display and source settings for future reference.  Suggestions for possible improvements to your system will also be made at this time.

During this process you can participate and see the improvements as they are made.  Detailed verbal explanations of the adjustments are also provided if desired.

    Audio

The first step is to listen to reference material.  This is useful in demonstrating the initial performance and determining where the system may be deficient.

The second step is to review the connections being used and modify the setup if it is not appropriate.

The third step is to take a detailed set of measurements that quantify the initial system performance.  This serves two purposes.  It documents how the system was performing before calibration for later comparison and it highlights where the current system is deficient.

The fourth step is to adjust the settings in the receiver/processor, speaker positions and subwoofer settings.  This is done using trained ears to verify solutions and spot problems, a reference microphone, test tones, RTA and FFT audio analysis tools.

The fifth step is a review of reference material to verify that the audio performance meets your expectations.

The final step is to provide a file of the before and after calibration measurements along with a detailed list of settings for future reference.  Suggestions for possible improvements to your system will also be made at this time.

During this process you can participate and see the improvements as they are made.  Detailed verbal explanations of the adjustments are also provided if desired.

6. What should I spend on cables?

A better question would be - "Can cables make a difference?".  Sure they can.  Bad video and audio cables do exist, but for the most part quality cables do not need to cost you a fortune.  You need a cable that can carry the signal and has connectors that will work well.  Don't expect different brands of cables to transform your systems performance to another level unless they are defective or of very low quality.

Here is a link to a video on this subject that explains these things well Video Demo.

Here is a link to HDMI Cable Test results.

7. Do I need a UPS or a surge protector?

UPS systems are generally not necessary and are not recommended for most applications.  Many UPS systems also do not generate clean power.  Ones that do an excellent job tend to be very expensive.  The backup power capability may be desirable on some devices and a UPS can be used if an additional level of reliability is required, but do not assume that the UPS will be delivering clean power.  An example of a type of device where reliability of power may be desired is a PVR/DVR recording device.  Purchase of a small UPS to only power these devices is recommended.

Surge protectors are recommended for all of this equipment.  This can protect your investment from a possible lightning strike or power problem.  Whole home surge protection along with local equipment protection is the preferred method.

Voltage regulators are not generally necessary except in large apartment buildings or areas with known power problems.  The same companies that make surge protectors also supply voltage regulators.

8. What type of connection (cable) should I use?

This is actually a fairly complex problem and one where many mistakes are made.  The primary problem is that many choices are available so the possibility for mistakes is large.

    Audio Connections:

*-Depends on the implementation
**-Analog only
***-Lengths may be exceeded with special equipment

Dolby Digital/DTS/CD Quality Audio

Various digital audio connections are available today that are excellent for this type of audio.  For most people the optical (TOSLINK) connection is a simple and easy way to get high quality sound.  This connection is found on most DVD players and cable boxes.  This uses a fiber optic cable to transmit the sound from the source to your receiver.  This connection is immune to ground loop problems and electrical interference.  Other high quality digital connections that can be used for audio are HDMI, coaxial and i.Link (IEEE-1394, Firewire).

HDMI is a connection that can contain the audio and video data stream.  This can be an excellent connection if you do not encounter some of the common problems.  Using HDMI for audio can have some problems with some sources (cable, satellite) due to various problems with how this standard is implemented.  This will usually result in no sound or picture when they occur.  This connection type is best used for audio when it is directly connected to the receiver.  When connected to a display and then to the receiver/processor it is unlikely that the audio data stream will be in the original format.

i.Link is a connection that can contain the audio and video data stream.  This can be an excellent connection if you happen to own devices that support it, but most do not.  This type of connection can also be used for higher quality audio formats like DVD-Audio or the soon to be released DTS-HD or TrueHD surround formats.

Coaxial S/PDIF is a digital connection that contains the audio data stream.  The capabilities of this connection are very similar to TOSLINK, but this uses a 75 ohm RCA connector instead of an optical cable.  This type of cable is susceptible to ground loop problems and electrical noise, but it does have the potential to have a slightly better sound performance than an optical connection because it skips the conversion to and from optical.  This type of connection is recommended for short connections when it is supported by both the source and the receiver.

Various analog connections are also available to transfer the audio from a source to the receiver/processor.  The best of these would be the multi channel outputs that require 6 or more RCA connections.  The worst would be your standard red/white stereo RCA connection. This may result in a loss of flexibility and/or quality and is not generally recommended unless DVD-Audio or SACD is required.  This type of connection is susceptible to ground loop problems and electrical noise.  This type of connection may be required if recording audio is desired.

DVD-A/SACD/DTS-HD/TrueHD Audio

This is where things get more complex.  The typical optical and coaxial connection used for audio does not support these higher resolution formats.  You are now forced to use one of a few connection types to take advantage of these improved formats.  This type of data can be sent in two forms.  The first is the raw un-decoded data stream.  The second is a high resolution decoded PCM stream.  The PCM stream has the benefit that the receiver/processor does not have to handle the various encoding methods.  This burden is placed on the source (DVD player, HD-DVD player...) when a multi-channel high resolution PCM stream is used.

HDMI and i.Link are the most common methods found that will allow the source to send this information digitally to the receiver for proper handling.  Either one is highly recommended for this if it supports all the desired sound formats and is compatible with your equipment.  HDMI version 1.1 will support a multi-channel high resolution PCM data stream.  HDMI version 1.2 adds support for SACD.  HDMI version 1.3 adds the ability to send all of these high resolution formats un-decoded.

Proprietary digital links also exist that support these formats.  They are also recommended if it supports all the desired sound formats and is compatible with your equipment.

Analog connections are unfortunately the most common way to transmit this information to most receivers sold.  This may result in a loss of flexibility and/or quality and is not generally recommended unless the other connection types are not available.  This type of connection is susceptible to ground loop problems and electrical noise.

Video Connections:

*-Lengths may be exceeded with special equipment

Video comes in several types of digital and analog connection types.  Digital connections are generally preferred over analog, but some displays may not support each type equally well making the best choice more complex than the audio connections.  All of the following recommendations assume that the display will use each input to its best advantage.  Unfortunately, this is rarely the case.

The best video connections transmit the picture information using a digital format that results in no loss of picture details.  These include HDMI, SDI, i.Link (IEEE-1394, Firewire) and DVI.  As long as the source and the display both support the connection anyone of these can be used to get the best quality image possible.  i.Link offers the additional advantage of being able to control the source from the display through an interactive menu system.  HDMI and i.Link can also carry the audio information which can be an advantage or disadvantage.  Some limitations with this are known to exist in various sources which can reduce or hinder the transfer of quality audio using these.  Digital connections may also be required to send the highest quality image by copy protection systems found in some source devices.

The next best video connection type are those that allow the most information to be sent from the source to the display using an analog connection.  These include component and RGB connections.  Both of these use multiple wires to get the information to the display.  RGB is typically the best when supported by both the source and the display.  A component connection is a three wire connection usually labeled YPbPr or sometimes incorrectly as YCbCr.  A RGB connector is a multi pin connector like that found on a computer monitor.  The benefit to RGB is that it can bypass a step of signal conversion and several possible conversion errors that can occur with component video.

The remaining choices are composite and S-Video.  It will depend on the source and the display as to which of these actually performs better.  The S-Video should in theory be better, but many implementations are poor.  An S-Video connection is a small round plug with four pins.  Because of the size of the connector and the number of conductors a quality S-Video cable is more problematic than other video cables in general.  A composite video connection is a single RCA connection usually labeled video and colored yellow.  This type of connection may be required if video recording is desired.

9. Reference Quality Blu-Rays

The following are films I have watched that have spectacular audio and video quality that will show your home theater systems level of quality and are also fun to watch.

• Australia

• The Bourne Ultimatum

• Cars

• Casino Royale

• The Dark Knight

• King Kong

• Ratatouille

• Spider-Man 3

• Transformers