Secrets Product Review

SVS SB12-Plus Subwoofer

Part III

November, 2006

John E. Johnson, Jr.


On the Bench

I was able to get a maximum of 116 dB at 1 meter, using our standard combination frequency test tone of 20 Hz, 31.5 Hz, and 50 Hz. That is a lot of power!

For such a reasonably small subwoofer, there is plenty of output at 20 Hz. THD+N is 12%, which is lower than I thought it would be. I really could not hear any harmonics at less volume, which is where consumers are more likely to have it set.

At 25 Hz, and 100 dB, a little more than 10% THD+N.

By 31.5 Hz, THD+N was less than 10%. It is suggested by many engineers that 10% THD+N is the audible threshold for deep bass.

At 40 Hz, THD+N was now quite low, at less than 4%.

And, at 50 Hz, just about 2%.

The unadjusted room response (yellow line) is pretty flat to about 40 Hz, then starts to roll off. I turned on the crossover and adjusted the PEQ to flatten the response to what it was at 30 Hz, shown in the red line. So, this single band PEQ is very handy. You might want to get one of those Behringer ECM8000 microphones (you also need a 48 volt power supply) I mentioned a while back, and use the free download program Audio Analyser to set your room response. This is a difficult to do using just an SPL meter, although that is better than nothing.

I adjusted the PEQ so that there was a slight downward slope from 40 Hz to 80 Hz, to take into account the slope of my ribbon speakers' roll-off.


I might normally say that I was pleasantly surprised at the performance of SVS' latest subwoofer, the SB12-Plus, but, although it was very pleasant, I am not surprised at all. SVS has consistently released fantastic products, and this one is no exception. If you have a big room and a budget to go with it, then buy something like their PB12-Ultra/2 which will have your neighbors running for their air raid shelters. Even that one is only $2,000, which is incredible for its performance. But, if you have a limited budget, and yet very much want to have a subwoofer that will just have you running for an air raid shelter, but not necessarily your neighbors, put the SB12-Plus on your short list.


- John E. Johnson, Jr. -

Copyright 2006 Secrets of Home Theater & High Fidelity

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