Your Room Hates You!
What is the most important component in your Hi Fi or Home Cinema system? Is it the Amplifier, Speakers, Source machines, or your display device? Well your answer to that question should read, none of the above. The most important component to any sound system is the room in which it is used. The physical space where your system is employed will have some positive effects on the sound, but in the vast majority of cases it will add detrimental sound waves, reflections and null points which can muddy the sound and cause boom and distortion. Combatting these effects requires the correct placement of speakers and electronics, along with room alterations like dampening boards, bass traps and sound dispersion treatments. Let’s face it, there is no such thing as the perfect room, and even specifically designed spaces for audio playback can introduce problems, albeit maybe with not the same degree of seriousness. In a poor room, you could spend thousands on the world’s best components and still have a final sound which is no better than a £100 mini system. So how do we combat acoustic problems in dedicated cinema rooms and living rooms alike? Well if you value your marriage, sound treatment on the walls is a no go, and more than likely you will also have to compromise on speaker and subwoofer positioning. So the only other option you will have is to use sound equalisation.
The use of EQ has been employed for many years in professional circles. Where sound systems are added to a room, a sound engineer is also on hand to make sure the EQ is a perfect match for that space so the system can perform at its best. However in the consumer market, and certainly in the world of the audiophile, EQ has never really been accepted as a solution, usually because the products available over the years have added more problems than they have solved. With general Sound equalisers they can correct the frequency response in a limited bandwidth but cannot correct the time domain of the signal. General EQ using fixed or even adjustable bands won’t correct an issue, either, as they can add phase problems which will affect the overall tonal balance of the sound (sometimes referred to as smearing or muddying).
However, in recent times we have seen some products hit the consumer market which help correct certain issues within the domestic listening room. An item like the Behringer Feedback Destroyer Pro has been an AVForums favourite for a number of years as a way to equalise your subwoofer within the listening room. There are other products like Velodyne’s SMS1 which performs the same tricks as the BFD, and system solutions from Lexicon and Meridian, all available at an extra cost, but none of them are as flexible, or have as much processing power as the unit we are reviewing here.
One name which has started to appear recently on integrated amplifiers, from the likes of Denon and Onkyo, is Audyssey. This system promises to fully EQ your cinema room by using the software built in the amplifiers and a small microphone. This approach works well, but as you will appreciate such software in budget to high end integrated amplifiers will not be overly powerful, but will make an excellent attempt to get your room sounding as good as it can within these limitations.
So what is Audyssey and what exactly does it attempt to do?
Remember the name Tomlinson Holman? Most Home Cinema enthusiasts will know that Mr Holman was the inventor and designer of Lucasfilm’s THX sound system, and in some circles it is even claimed that Holman is the namesake of the system (Tomlinson Holman eXperiment), although Mr Lucas may have something to say about that.
Holman and Chris Kyriakakis set out to determine the negative effects that room acoustics have on sound and in that process, design technology that would correct almost every room. They founded Audyssey Laboratories with other researchers and after five years of intensive development, funded by the National Science Foundation in the US, the University of Southern California (USC) based team designed the Audyssey MultEQ products.
Both co-founders of the company have won almost every prestigious award in their given field from an Oscar for Holman’s THX work to the 2006 World Technology Award for Kyriakakis. After reading both men’s biographies you soon realise just how experienced and influential both are in the field of acoustics and sound design.
Both men are behind the development of the Audyssey sound equalisation techniques and because they are software based, it allows the technology to exist at various levels within the market. Currently there are four versions of MultEQ available for consumer use.[img=products.gif width=126 align=right watermarkit=no]
The Audyssey Family Tree
The baby of the family is Audyssey EQ, a system of basic software correction based within an all in one system that is provided with its own speakers. With these Home Theatre in a Box items as well as some Television sets, Audyssey works with the manufacturer and tests the systems in their labs to precisely measure the performance in a typical room. The EQ software removes distortion from the units’ speaker system as well as the typical room environment so it can produce the best possible sound in the circumstances and it’s claimed better than comparable systems on the market.
Next up is 2EQ which as you can correctly assume from the name, takes two measurements inside the room before calculating the distances and frequency responses and applying them to your system. This technology is available in some budget Integrated amplifiers and receivers.
From here we move to MultEQ which can be found in mid to high end receivers and amplifiers. This time the system works out everything based on six position measurements as well as using mid-level resolution filters for satellites and subwoofers.
Finally we have MultEQ XT which is a split specification between two implementations for use. First is the most powerful version of MultEQ available on high end receivers and amplifiers. It uses the same technology as the third example but this time ups the number of measurements to eight positions within your listening bubble.
The second implementation of MultEQ XT is what we are reviewing, here. A stand alone unit that normally has to be installed by your dealer, and which uses state of the art MultEQ Pro software and set up kit. It allows up to 32 positional measurements of the listening position and because it uses a PC or lap top for the calculations, you have some serious processing power for the software to solve the mathematical problems, and create the perfect response for your room. Once you have finished, and are happy with the result, the PC then downloads the settings to your box and that’s it - all set up and perfect!
The sound equaliser is a normal width unit which can be rack mounted if required, and sits between your AV processor and amplifier. It is a rather neat design with a sleek aluminium front panel, with two small LEDs at both ends, and an EQ button in red. That’s it. There is nothing more to the front panel and the stylish looks will fit in with any AV system you connect it to.
Moving to the rear panel and things look a little busier. Here you will find 8 analogue audio inputs and 8 analogue audio outputs, a USB port, Rs232 port, an on/off switch and a three pin power connector socket. So it looks busy, but not overly so.
The most important part of this unit is not the actual box but the installers’ kit bag. The bag contains a high quality microphone stand, numerous XLR to XLR male and female cables, an installation manual, a calibrated microphone and a calibrated microphone pre-amp, a USB 2.0 cable and the all important MultEQ Pro software CD-ROM.
You will have noticed that I mentioned the word calibrated when referring to the Microphone and that is very important. Before being shipped to the dealer, the software CD, Microphone and microphone pre-amp are all calibrated by Audyssey to a set standard, and numbered as such so you know that the components here are all matched. This helps with the integrity of the measurements taken by the microphone and the software.
The software and manual go hand in hand on your first installation attempt and both are intuitive to follow and understand. The software takes a matter of minutes to load up onto your lap top or PC. You can’t run along and get lost, either. The software works in steps and will not allow the next step to be performed until you have successfully completed the last thing you were doing.
Most people who invest in this unit will have their dealers set it up for the room calculations and then just leave the unit alone. However for those who like to do things on their own, or who are constantly changing their equipment in their room (such as reviewing equipment), you can purchase the set up kit along with the unit at an extra cost.
Let’s get one thing clear right from the start - this is not going to take hours and hours of your time. Unlike, say the BFD, which requires serious time investment to get the best results, the Audyssey software and set up techniques are a lot easier to follow, and the end results are simply staggering. But more on this later.
First up are the loading of the software, breaking open the installer’s kit and assembling the microphone stand and cables. The microphone will be positioned in the listening area, not just at the sweet spot, but across all the listening positions of the room, creating what they refer to as a bubble. The really important thing here is that you get as many positional measurements across this area as possible. In my room I measured a total of 27 positions across three listening positions. The reason for so many is to give the software the best possible results, and plenty of them, so it can accurately calculate the response and timing results, and then give you the best calculated response curve for your room (and each speaker).
So let’s start at the very beginning. I positioned myself at the door of my room, next to my equipment rack and to the right, just behind the front speaker array. This position meant that I was out of the listening position yet close enough to the rack so I could plug in the USB cable and microphone pre-amp and sit next to my lap top. If you have a dealer install the unit, they will log into the Audyssey website and create an account for your job. This will mean that all your results can be uploaded to the site and you receive a nice certificate that visually displays the before and after results of your room.
You have a couple of set up screens to go through with the software. This allows you to select what each of the eight channels will be assigned to. Called zone configuration you have eight drop down menus, each positioned next to a channel. The default settings are identical to most AV processor input and outputs, and will not need changing.
Channel 1 – Left front
Channel 2 – Right front
Channel 3 – Centre
Channel 4 – Subwoofer
Channel 5 – Left Surround
Channel 6 – Right Surround
Channel 7 – Left Back Surround
Channel 8 – Right Back Surround
You can change any of these Channels by clicking the drop down and selecting the desired output from the list. The Audyssey also allows you to use two zones separately so you can have a 5.1 system in one room and a 2.0 system in another. Channels 1-4 have higher resolution filters than the remaining channels for satellite speakers and you are advised to use channels 1-4 for those.
Next up is to connect the AV Processor to the unit. You do this as normal and from the list above, however you do not plug in channel 1 at this time, this is left for the calibrated microphone during set up. You then connect the output from the Audyssey to your amplifier, or in my case my active speakers directly. Once you have done this, and switched the amplifier on, connect the calibrated microphone to input 1, and you are ready to get started by selecting a zone. In my case I was using a 5.1 system so I selected zone 1. However if you do want to have the extra channels running a separate stereo set up in another room, you can select that from this point in the software.
The next option page in the software set up is the room dimensions, and you are asked to provide the width, length and height in three separate boxes. This calculates the square foot coverage of your listening room and is used as the first reference point for the software.
Once I was all set up, with the microphone in the correct position at the first point, it was a simple press of the mouse and the first cycle of test pulses where emitted from each speaker, one after the other. At this point the software will tell you if your speakers’ polarity is correct and this is where the unit confused me! I use Mackie HR624 active THXpm3 speakers, these are self powered with the amplifiers built into the speaker cabinet. However, the software was telling me that 3 of them where the wrong polarity. So after manually checking each and every speaker and checking with someone who has used the unit extensively, it was decided that this was just an anomaly with the software. The person I checked with, Neil Davidson, our podcast roundtable technical guru and industry all rounder, mentioned that even his multi thousand pound sound meter gets this wrong from time to time so I stopped panicking and went back to the set up.
The set up from here really is just a case of running the test pulses, letting the software save the filter, then moving the microphone to the next position and repeating the process. It is important that you get as many positional measurements as possible to allow for the best possible result when the final calculations are done. You are given a maximum of thirty two such positions. During the measurement cycles, the sound emitted may get louder on some channels than on others. Audyssey say this is because they have designed the test tone to play a series of full bandwidth signals to measure the rooms response and because it doesn’t use pink or white noise, the final measurements are a good indicator of the rooms signal to noise ratio as it doesn’t pick up background noise as much. Audyssey also calculates the optimum bass crossover frequency for each speaker based on all the positional measurements. It is claimed that the most accurate method of determining the correct crossover frequency is through the room measurement, because the room acoustics will affect how far down each speaker can play in your given room and position. Because the system measures over multiple listening positions it determines the optimum crossover that provides the best blend between the subwoofer and satellites based on complex amplitude and phase results. This means that the calculations take into account what your speakers capabilities are so they are not overdriven, and as a result the crossovers may be different for each speaker based on these complicated calculations. The end result though should be a seamless blend of sound that arrives at any of the listening positions in time and free from room resonance and distortion.
After measuring all of your positions it is now time for the software to do its thing and first of all return its detection results. At this point you are given a screen which tells you the exact distance to within ¼ inch of each speaker. You must then enter these results to you processors set up menu for speaker distances. In most cases the processor will not give you the exact distance like that on the audyssey software. In this case you should round up to the nearest selection point given. You may find that because of low level noise that the human ear can not hear (but the microphone may have picked up), the subwoofer distance may be out, sometimes by a couple of feet. However such is the power of the software you should only enter the exact distance the audyssey gives you, as the measured distance in the software will in fact be correct.
The detection page also gives you the correct crossover frequencies for each speaker, however not all processors will allow you to dial in each speakers result. In this case your processor will probably bunch the crossover of two or more channels together, so you should select the highest from the drop down menu possible for your front channels and do the same for the rears. If you are still unlucky in this regard and can only select one crossover for the entire 5 channels you should use the first crossover point that Audyssey gives you for the centre channel on the detection page.
Once all that is set up and correct you are given 4 target sound curve options to try out on the system. You can do this by selecting the desired curve and then playing material on the system and selecting the on /off switch in the software to compare before and after results. The Audyssey software calculates an EQ filter for each channel including the subwoofer. The purpose of these filters is to achieve a particular frequency response within the entire measured listening area for each speaker and creates a target curve for your room. Audyssey state that contrary to popular belief a target curve that is totally flat from 20hz to 20khz is not always the one that will produce the correct sound. The reasons given are that loudspeakers are much more directional at higher frequencies than they are with low ones. This means that there has to be a balance of room and direct sound to attain the correct response curve.
Overall the software uses clustering of certain frequencies which have the same characteristics or fuzzy logic as they call it. This is said to be far more accurate at determining the most appropriate correction for all listening positions. To go into more depth about the whole science that Audyssey preach then log on to www.audyssey.com
Once I was happy that I had covered everything in detail and gone though all the steps correctly, I chose response curve number 1 which is designed for THX based systems, and downloaded the filters to the Audyssey unit. Here are the results for each channel. Top is before, below is after in each picture.
(Note : the subwoofer volume looks low on the graph, this is not the case in practice.)
As you can see from the above pictures, the measured results and then the correction added are just staggering. The major difference here is the subwoofer channel, look at the before and then the after results, let me tell you I am now getting a bass response that is unbelievably good to listen to, and a mid range from the system that just never existed previously. You know something is good when you break out the old test DVDs and CDs.
The first thing I did was play some music. I have a Lexicon MC1 in the reference system at the moment, and if I am really honest the music performance of this processor is not great. It sounds far too clinical at times and lacks any real sparkle. However switching the EQ on and off (using the default button on the front of the unit) provided all the evidence I needed that my room had been destroying my sound quality before I installed the Audyssey. Playing Annie Lennox: Cold (From the CD Diva) was a revelation. With the EQ active the soundstage was wonderfully wide with a large sweet spot as I changed chairs, that voice always anchored as close to centre as possible. And I was suddenly hearing things within the track that I never knew existed. There is an almost silent sigh after the first verse on the right hand side of the soundstage; I have never heard this before, ever!
The main thing that got me going was the mid range frequencies that obviously had been taking a holiday in my room for the last three years. Suddenly the whole sound had a warmth and kick that was never present beforehand, and a vocal from Lennox that was now something to get lost in. Did I mention the bass performance? Well again this is just another area that I obviously have been missing out on, big style! Just look at those result graphs above! Bass is now tight with no lag, and I am also tempted to say in time! That’s right, it stops and start on a dime, where in the past it would have a terrible lagging feel. Now the bass was what it should always have been - tight, tuneful and in time!
Now comes the fun part. Lets switch the EQ off and listen again. WOW, what a mess! I really can’t believe that I was happy listening to my system before this unit arrived; well I thought it was reasonable, but boy was I wrong! The soundstage collapses with a mushy bottom end and the vocal just doesn’t have that same creamy texture, the mid range gets completely lost and that sigh, I know it’s there now and yes I did hear it this time, but only just.
I decided to switch the Projector on at this point and introduce the Audyssey to my HD DVD collection.
First up was King Kong and the raptor race, as I settled back I began to wonder where that great sound had gone. I could hear no difference with the 5.1 track and was puzzled to say the least. At this point the penny dropped, the unit has a light on the far right side of the face plate, and this is green when the EQ is engaged and Red when it is not. Guess what?
So, after listening for 5 minutes I decided to switch the EQ on again. Now what I don’t want to do here is get all overboard and use words like, wow, fantastic, mind blowing, sensational or even life changing so I will use one word….Stunning! It now dawns on me that I am finally getting to hear my Mackie speakers and Velodyne subwoofer do what they can do, and my processor now sounds like the £5k unit it once was. The effect of having the room acoustics calculated and then applied in such a way has made a major difference to my listening environment. I am now getting the best out of my components; the room no longer vibrates at certain frequencies in a noticeable way and the major difference? Bass that kicks you in the chest and then runs away, like it should! And a midrange I never knew was possible! I am sorry dear reader but I have fallen in love and it’s for clean, crisp, dynamic and scintillating sound that is free from distortion and room inflicted problems, and the Audyssey is to thank for all that and more. I have spent the last 6 weeks transfixed with the sound and going through my software library like never before. I said I wasn’t going to get carried away, but I must apologise, this thing is just amazing!
What hits home the most is that I assumed my system was set up at its best in my dedicated room. I knew there were a few acoustic problems but always just accepted that. To have your eyes and more importantly your ears opened to what your system is actually capable of is a shocking, yet stunning experience. And you can see in the results photos my speakers were not overly bad in this room, but now the timing, phase and crossovers are perfect and with properly calibrated filters applied, that price tag for the Audyssey now looks like the bargain of the century!
- Stunning results which correct even the most difficult room problems.
- Ease of use in set up, very intuitive to master.
- Real time results so you can hear the difference the filters are making.
- Clearly the best room correction system on the market for both Home Cinema and Hi Fi.
- Price may put a few off.
- Needs to be used with a processor and amplifier.
Audyssey MultEQ XT Pro Sound Equalizer Review
I could have gone on with my results from the listening tests, but if what I have written above hasn’t made you curious in the slightest, I don’t know what will. In all seriousness this piece of equipment is probably the most important product to hit the market, yet. It is a truly mind blowing technology which has finally cured the biggest problem that anyone who loves hi fi and home cinema has - their room.
I cannot stress enough that you really should get to a dealer and check this magic box out now! Don’t even consider buying another piece of equipment until you hear this unit, this will be the biggest and most cost effective upgrade you will ever make to your system……period.
The Audyssey system truly is an industry changing product; you could see that at a recent trade show where most manufacturers seemed to be running scared and in denial. The power and flexibility, along with its simple set up and stunning performance envelope will change the way many of us approach building a system in the future. For everyone else, you don’t know what you are missing. The Audyssey MultEQ Pro is a reference quality product that is set to change room acoustic problems for good, and let us all enjoy our movies and music in the best way possible, and in stunning detail!
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