tune in-set a subwoofer

[InVeNtOr]

about a year ago it was finally brought to my attention to buy a spl meter and tune my speakers in or balance them, if thats the better word. what i still don't know is how to tune in or set the subwoofer. my confusion is, when you do the test tone and all the speakers hit the same db level, what db level does the subwoofer have to hit? i redid my speakers last night but when it came to making the sub hit the same mark, my entire living room shook. does the subwoofer have to be at some relative db level or do you set it to your liking?

thanks for the new information

[kevinmi]

I'm sure you will get some tech guys to tell you how to set everything correctly, but for me I use the ear method. Set it to your own preference and be done with it. Over-tweaking will drive you mad! -kevin

[SWL]

I'm sure you will get some tech guys to tell you how to set everything correctly, but for me I use the ear method. Set it to your own preference and be done with it. Over-tweaking will drive you mad! -kevin

Amen!![]

[InVeNtOr]

so the K.I.S.S. method works best, i take it.

[Islander]

Getting the SPL meter is the first step. Along with the receiver's test tones, that's all you need to balance the main-range speakers with each other. To match the sub to the other speakers, it's very helpful to have a source of tones below 200Hz, down to 20Hz or so. There are tone generators, but a test CD or DVD is all you really need.

Sit at your listening position with the meter and see what it shows you. The more knowledgeable forum members may jump in and point out the weaknesses in this basic technique, but it will get you in the ballpark.

It's a good idea to make up a chart and note the readings at each frequency, because it'll take quite a few tests to get the sub properly dialed in. First do a test run without the sub, so you see the response of the speakers and the room. You may want to use what you learn to find the ideal position for your main speakers. This would be the distance from the walls that gives the smoothest bass response, with the minimum of peaks and dips.

You'll also find where the low-end response of the speakers starts to trail off. It may be somewhat higher than the specs would have you believe, but that's what the sub is there for. As a starting point, set the sub crossover in the receiver around the point where the speakers are down 3-5dB. Set the rolloff or hi-cut control on the sub itself all the way up and make your adjustments with the receiver. Set the sub's volume or level control around the 10 o'clock position and adjust its volume from the receiver as well. As for the phase setting, I'll let someone more experienced explain that more clearly than I could.

When you run your test tones, you don't need to use high volume. 80-85dB is plenty. Your aim is to have a relatively flat or even response from 200Hz down to as low as your sub will put out in your room. Depending on the sub's abilities and the room's size, it will probably roll off around 25-30Hz. Since a 4-string bass guitar's lowest note is at 40Hz (a 5-string bass's extra string lets it go down to 30Hz), that should be enough for most music, other than some organ or electronic music.

You will have some peaks and dips in any case, but do your level and hi-cut adjustments to try to minimize them. If there's a dip or peak around the point where the speakers and the sub meet, adjust the sub's hi-cut up or down as needed.

When you've got it all set, the sub's sound should not be obvious. An acoustic or electric bass should sound realistic, not too light or too heavy. The numbers are all very well, but how it sounds to you is what's important.

Finally, some may disagree with me on this, but I think that a correctly dialed-in sub should work equally well with music or movies. If the music sounds natural, the explosions and earthquakes will also sound the way the director wanted them to sound.

Hope this is helpful.