Frequently Asked Questions (FAQ)
Q: Why expert recommend 80Hz as the most ideal cross-over?
A: In a nutshell, the human auditory localization worked in mysterious ways…studies shown that anything below 80Hz, the sound will cease to be “directional”, the sound becomes harder to “localize” - i.e. it becomes omni-directional. This is commonly referred to as the low-frequency effect (LFE). What we want to achieve is that the high frequency effect will be directed to the speakers for reproduction - “directional” and the LFE will be reproduced by the subwoofer. Such distribution of high and low frequency will help to alleviate some of the speakers in the LFE reproduction…let’s face it, not all speakers are designed to do both high and low frequency very well…worse is not all our speakers are using the same make and model…dun even make me start with the Re-EQ and timbre-matching as advocated by THX…The best solution is to direct all LFE to subwoofer to prevent what we call, "double-bass’ or “muddy-bass”. Of course, I am discounting on the fact that there are times where properly calibrated (using phase control), one may experience an increase in headroom a smoother response. But this is rarely the case, unless your entire 5.1/7.1 systems are of the SAME BRAND. But we all know that SVS, Rythmik, Ken Kiesel etc made better subwoofer than say a matching one like Monitor Audio 5.1 system in a package.
Q: After calibration, Audyssey “recommends” a 40Hz roll-over for my Mains? I dun understand why is that so IF the above argument holds true?!
A: According to Audyssey, the roll-over at 40hz is actually “determined” by the AVR and not Audyssey. During the calibration process, the test tone generation for each speakers “send back” the information to the AVR to set the speaker roll-over at a certain range…based on the speaker capability. If you based your prediction solely on the “looks” like a tower speaker should have a lower roll-over since it is more capable to reproduce LFE at a certain range, then you might be wrong. I can safely say that we can choose to ignore it…As a general rule of thumb, for full range tower and bookshelf speakers, the ideal roll-over should be pegged at 60Hz - 80Hz while for a satellite speakers, it should have a range of 90Hz - 100Hz or higher.
ii) Ensure that the Low Pass Filter (LPF) is set to the highest. In my Onkyo AVR, the highest LPF is set at 120Hz. You may ask what about the LPF knob or switch at the back of the physical subwoofer itself? What does it do? Well, quite frankly, you need not worry about it…you can literally leave that alone. But just to ensure that the subwoofer will “listen” to the command from the AVR, flip the switch or turn the knob to the highest point and leave it there. The LPF switch at the back of the subwoofer is usually meant for 2.1 speaker setup where the stereo preamp may not have a LPF setting built-in. Most of the AVR these days DOES NOT need that as most have LPF setting built-into it.
iii) Ensure that the bass management is properly set in your AVR. Disable any LFE+Main function if you see this. Ensure you only select LFE Only for the bass management (see above for the rationale)
iv) Leave other settings intact - e.g. speaker levels and distance. Don’t mess with the distance and the speaker levels or you will indirectly screw up other settings like Audyssey Dynamic EQ.
v) Whilst reviewing the post-calibration results, ensure that the subwoofer level DOES NOT exceed +/-6db. A correctly calibrated subwoofer should have very little need for change to the level (SPL)…This is the reason WHY you need to dial in the subwoofer to be at 75db before the commencement of the calibration process - for newer models. For older model AVR, you need can use a SPL meter to measure the subwoofer sound pressure to be at 75db before commencing the calibration process. If you do not have a SPL meter, then you can adjust the gain knob at the back of your subwoofer to somewhere between 11 o’clock to 1 o’clock. So if the trim values showed an extreme negative figure of say -8 or -10. You probably have your subwoofer’s gain knob set too high. Lower it and re-run the calibration.
Q: Why is there such a huge difference in the distance measurement for my subwoofer? Did Audyssey screw up?
A: No. Audyssey did not “screw up”…In fact, Audyssey does not actually “measure” distance in its literal sense…what it does is measuring delay in signal that was send over from the speaker or in this case, the subwoofer to the listening position (where the calibration mic is located). The delay is due to the electrical delay inside the subwoofer. Recall when I mentioned that Audyssey uses correction filters? The use of filters will inevitably cause some “delay” in the signal. Hence a longer distance is used to “compensate” that…so it is perfectly normal to see a distance of say 5.5m away from the listening position when in actual fact, the physical distance is approximately 3.5m away. This helps to ensure that LFE complements ALL OTHER SPEAKERS in the array to ensure sound reaches the ears of the listener ALL AT THE SAME TIME.
Q: Why Audyssey sound different at my friend’s place?
A: Audyssey calibration “interacts” closely with your room modes…it is because of the room modes that is causing the difference in sound quality. What Audyssey tries to achieve here is to deliver the same level of auditory experience you hear in a dedicated showroom or perhaps your friend’s setup and deliver it to your home. Whatever settings especially the roll over fq for individual speakers…it is the result of interacting with you room…hence whenever you change some layout in your room such as addition or removal of a piece of furniture or even seating arrangement because you just got yourself a bigger couch…you will need to re-run Audyssey again to ensure optimum sound reproduction for your speakers.
Q: Why do my center channel always sound so soft after calibration? I always have to increase the gain for my center speaker and use dynamic volume (light) to compensate.
A: I am not surprised that you are having this center channel “too-soft” issue…as many home theater enthusiasts have experienced it at some point in time after the calibration. For me, there is NEVER AN ISSUE with the center dialogue. And nope, I did not engage in any Dynamic Volume as it will not yield good results…trust me, I have personally use it one time and abhor it! And you should not use that as far as possible.
For your problem, there are a few things you can try…but before that need to ask you a few questions:
Q1) Are the front left and right speakers the SAME MAKE as your center speaker?
Q2) How did you position your center speaker?
Q3) Did you do a “reference test” using either a SPL meter to measure and ensure that the pink noise (test tone) emanated from the AVR is about the same sound level? Do the “level” (or volume) sound uniform whilst cycling between the front left/right and center speakers?
Recall that I mentioned bringing your speakers at ear-level? This is ESPECIALLY important for the LCR. For the surrounds and surround backs, the concept at ear level need not be followed as after all, there are meant for “surround effects”…for the most part, the main SOUNDSTAGE lies with the LCR (Front left/right and Center speaker). So if you center speaker is pemphasized textlaced too low - say at your chest level, try to use something to elevate the angle to point towards you. If you pay close attention, almost all home theater setup have one or two common things or should I say “sight”…the center speaker is ALWAYS NOT AT THE IDEAL HEIGHT owing to the big TV/Projector screen…nobody want the center speaker to “block” the view, I get it. But that is a compromise here…So you can try out the following:
Solution 1: Elevate the center speaker to point at you.
Solution 2: Move your seating position further away from the screen, so that the center speaker points at you directly. And yes, you have to re-run the calibration again.
Solution 3: If moving your seating position is not possible due to space constraints, perhaps you can consider “elevating” the screen or your TV higher so that you can bring up the center speaker to ear-level. I know you neck is going to be strained…then adjust your recliner chair to a height where you can just lay-back at a comfortable angle. If you dun have a recliner chair, then you should consider getting one.
It is okay to increase the center speaker volume by a few dbs hotter than the rest. Remember getting the LCR right is crucial in a typical 5.1/7.1 setup. Next comes the subwoofer. With these two things solved…I guarantee you will get the best home cinematic experience of your life time.