Is a Cerwin Vega cva 121 powered sub good for home theatre surround sound?

BBT91945, read the question, this is a POWERED sub. He won't need a separate amplifier for it. Read the question before you answer it. You shouldn't expect a subwoofer to produce midrange tones. That is why it is called a SUBwoofer, it produces tones below what a standard woofer produces. It is impossible to know how to advise you when you give us no information about your other equipment. 21 inches is mighty large for home theater.

Actually no, this would not be a good sub for home theater and here is why... Frequency Response: 35 Hz - 135 Hz (±3 dB) For home theatre to be truly enjoyed, you need subsonic frequency capability and this doesn't even come close with a cutoff at 35 Hz. Getting down to subsonic at all isn't an easy task and doing it with low enough distortion to make it effective is far more difficult still so it's not really going to happen with any typical commercial sub. However, you can certainly do a lot better than 35 Hz! That's terrible!!! Sure it would boom the heck out of the house but not at truly low frequency. Despite comments by some, the CVA121 isn't overkill for HT in any respect. There is no such thing as having too much capacity, only having too much. Gains need to be set properly so bass isn't over ridding everything else but unlimited capacity would be ideal so there is simply no such thing as having too much capacity. The problem is with this sub that it just can't get low enough. Ideally you wouldn't even cross into the sub above 40 Hz or so and this sub stops working almost at the point it needs to start working. For it's designed application...Rock music etc, it's perfect because that type music seldom gets below 40 Hz. For HT, getting down to single digit Hz would be ideal and anything less than the low 20's is just unacceptable. You need to look at companies like SVS. This http://www.svsound.com/products-sub-box-pb13ultra.cfm will work much better for HT than that thing you are looking at. Especially if you use at least two of them. Again, it's not that the CVA121 is overkill or low quality or any of those issues, it's just that it's not appropriately designed for HT. It works best in the wrong frequency range. The SVS will serve you much better or even better still, you could do a custom design if you are handy with the hands and don't mind DIY. With DIY there are no limits, I personally use twenty four 15" subs in my HT (now you know why I say a single 21" isn't overkill) and I have flat response to 13 Hz. I'm currently working on a "sub-subwoofer" to get down to 7 Hz. It will have the effective surface area of almost 100 15" woofer cones. So not overkill, the CVA is just not right for HT. mk

Cerwin Vega are not a very good speaker. There are not many subwoofer that are rated more than 300 watts. If you want that much power you are going to have to pay for it. Look at the DJ or commercial use, like a JBL subwoofer with a dual 15" but they are only rated at 500 watts. Keep in mind that all sub woofer only handle 150HZ and below, You also need a high rated power amp to push those speakers. Hope this will help you out.