I have seen several different ones on the net and I am wondering if even better results could be achieved. This entire disk never sounded correct in the past. Thats two bass or kick drum hits per second. You hear differently than the sound level meter does…trust your ears, not the meter. Looking at the diagram above this is around 65dB so the -6dB point relative to that is around 40Hz. To find the acoustical rolloff you need to try and fit a straight line to the frequency response measurement.
And it works very well. Since I have no other equipment to verify my results with, I can only go with what I have. Many people get confused by polarity and phase. If the nulls are just a few db's then a little boost is Ok, and I do stress little. But remember, the only difference you should hear will be in the frequency range, not the loudness. You are in for a unique audio experience.
Since consumer equipment operates sort of backwards, when you increase the distance setting of the sub you are adding delay to all the other channels. Windows 7 and Windows Vista feature a more thorough way to demonstrate how the speakers are set up, including a stereo test. Something that I now know was being covered over by that severe peak at 63Hz that I had. It matches the output of the source unit to the input level of the amplifier and features Gain Matching to prevent clipping the input. My bass was now almost ruler flat according to the meter and the Rives tones and I only had to boost ever so slightly at a few points. Rives doesn't mention it so maybe I am worrying for nothing but it would be a comfort for people like me to know. Theoretically speaking a 6dB filter has 90 degrees of phase shift at the crossover frequency and each extra 6dB adds 90 degrees, so a 12dB filter is 180 degrees out of phase and so on.
This is completely wrong. Again, without these tones I would have never of known this. While the recordings themselves are all superb, they are of a different enough flavor to keep you on your toes. Therefore the test is essentially a waste of time with more modern subs, but I have included it here anyway. Fun bass, sample music, and dynamic snippets. Even if you later put the sub where your spouse suggests, you will have first learned whats actually best.
There is of course delay in a sub. I attached long cords on my sub, placed the offending 63Hz tone on repeat and started moving my sub around the room until I got the tone into a more manageable range. If you have compact satellites, set the low pass filter to 120Hz to start. Then adjust the delay setting for smoothest frequency response at and around the crossover frequency. The good news is; there is help and it is affordable. If the reverberation time in your room is 1. Notice all the peaks and dips holes.
The voiceover tells you the frequency you have reached. If your main speakers are bookshelf designs or in-wall, set the low pass filter in the 80Hz range. In other words, you should add a subwoofer to your main speakers to extend the frequency range of your system toward lower frequencies, not increase its bass level. That is my second complaint. Practically the delay caused here is significantly lower than the delay caused by the crossover. You will hear a difference though, as each kick offers a different depth. After going through the rest of the tones out to 20Khz I found out my room wasn't to bad, aside from the expected few nulls and a peaks.
When setting the phase setting by ear, play some music not a movie that has a walking but repetitive bass line. With more than five octaves separating the bass range from this frequency, imagine the bass boost! For one the crossover between mains and sub is not a brick wall. Guess what: these tracks are from 1993 and are completely analog. Quite many pros and cons for each. There is no delay in the subwoofer due to its heavy cone. Once it was facing down this all but disappeared on the low frequencies. All you'll find doing that are the modes at that single frequency.
Flipping the polarity switch for a check gave the blue line. Now the bass seemed natural and balanced and I could clearly hear every note change and nuance on the stand up bass. Then spray paint with flat black barbecue paint and you will have a professional port seal. In essence we cannot tell where a sound at these frequencies is coming from. Therefore if you turn the volume down on the sub s , you can use this test to determine absolute timing of other parts of the system. You will hear a sine wave start at 150Hz and gradually decrease to 1Hz over the course of 60 seconds.