Dual Subs

[edubb5]

Originally Posted by Big Daddy

This question has been asked and answered in multiple threads. With two subwoofers, it is best and easiest to have identical subwoofers from the same manufacturer. However, with a little patience and experimentation, you can make two different subwoofers work with each other. The bass response in a room can be very uneven. Depending on the position of the sub or your listening position, you may experinece cold and hot spots. This due to interation of low frequency sound waves with the room boundaries and creation of standing waves. An easy solution is to use two subwoofers. In almost all cases, two subwooferes are preferred to one. Placement of the two subs is very important. Research has shown that the best positions for tow subs are:

1. Middle of the side walls.
2. One in the middle of the front wall and one in the middle of the rear wall.
3. The two right and left front corners.
4. When you have different subwoofers and one is stronger than the other one. Put the bigger (better) sub up front in a corner and put the smaller subwoofer on the side or behind your sofa (a few feet away). With this arrangement, the bigger sub up front will give you deeper and lower frequency bass sound and the smaller sub will give you the upper frequency and louder bass sound.

It is very important that you adjust the level of each sub independently.

1. On the back of the subs, turn their levels to 50%-60%, no higher than 75%.
2. On the back of the subs, turn their crossovers all the way up to their maximum point. You set the crossover in the receiver.
3. In the receiver's menu, set all speakers to SMALL.
4. In the receiver's menu, set the crossovers of all the speakers to 80Hz. You can deviate from 80Hz depending on the low frequency extension of your speakers. Make sure the crossover is always set at least 10Hz-15Hz higher than the minimum frequency response (+-3dB) of your speakers.
5. In the receiver's menu, set the crossover frequency of the LFE channel to 120Hz.
6. In the receiver's menu, set the level of the subwoofers to zero.
7. Turn off one subwoofer.
8. Play the test tones through the subwoofer that is on and measure its response with an SPL meter or your ears. Adjust its level on its back (not the receiver) so that you get approximately 75dB.
9. Turn on the other subwoofer and turn off the previous subwoofer.
10. Run test tones through it and adjust the level on its back so that you get approximately 75dB.
11. Now, turn on both subwoofers and do not touch the levels on their back.
12. Run the calibration program again or use an SPL meter.
13. If you are using an SPL meter, when the time comes to adjust the subwoofers, move the SPL meter slighly to the right and slightly to the left and average the dB level that it registers.

Hopefully this will work. If you move the subwoofers or move your listening position, don't be surprised if the level of the subwoofers change drastically.

Read A Guide to Subwoofers (Part II). Post #2 in that thread discusses positioning and the importance of using identical subs.

Should the Spl meter be turned toward the speakers? Or Up? Like a sound mic for Mcacc or Audyssey