Setting Crossovers for Polk TSi series

You'll likely want to set them all at "small" so they can crossover to the sub.

I looked up your speakers on Amazon and the specs cited a low frequency limit of 34Hz for the mains, 35Hz for the surrounds, 53Hz for the backs and 48Hz for the center. An 80Hz crossover point will probably work just fine. It will give you enough overlap to achieve a smooth transition between the subwoofer and the other speakers.

If you can set the crossover point on the back channel independently of the others you might bump that one up to 100Hz. the claim of 53Hz low frequency cutoff frequency on a 5.25" driver with a rated efficiency of 89dB seems a little optimistic.

Oh, and either disable/bypass the crossover on the subwoofer or set it as high as it can go. The receiver will take care of all that business.

You are better off setting the upper f limit ON THE SUBWOOFER to around 80 Hz.

Otherwise it might double the other speakers and muddy up the sound.

The bass management in the receiver will take care of this. If the low pass filter in the subwoofer is set at 80Hz and the receiver implements an 80Hz low pass filter as applied by bass management the sub will roll off too fast. Additionally, the LFE channel can contain information up to 120Hz which would be filtered by the subwoofer if the low pass filter in the subwoofer is engaged.

You should set all of the speakers to small, and set the crossover to as high of a low pass cutoff as possible.

http://www.polkaudio.com/products/tsi400

I'm not the least bit impressed with the TSi 400 5.25" so-called woofer, floor standing enclosure or not. Putting a woofer in a larger enclosure can improve bass extension and efficiency, but it can't change the maximum undistorted SPL versus frequency.

An optimistic estimate of its capabilities for undistorted SPL based on a very optimistic number for woofer Xmax and cone area is:

Freq,Hz Max SPL, DB

10 61
20 73
30 80
40 85
50 89
60 92
70 95
80 97
90 99
100 101
110 103
120 104
130 106
140 107
150 108
160 109
170 110

As a mid-fi speaker I would recommend a crossover of 100 Hz.

As a high end speaker I would recommend a crossover at 170 Hz.

Your subwoofer is very much lower end mid-fi so 100 Hz is my recommended number. It's 10" driver again very optimistic estimate:

Freq,Hz Max SPL, DB

10 78
20 90
30 97
40 102
50 106
60 109
70 112
80 114
90 116
100 118
110 120
120 121
130 123
140 124
150 125
160 126
170 127

Probably not bad down to 40 Hz. for a mid fi system.

+1. Leave the crossover knob on the sub to 120hz