I thought I'll write some update on my subwoofer case. Little over a year ago I bought PB-13 Ultra with new Sledge amp. I then wrote here about the noise floor of the amp. I also discussed with my supplier and SVS and they said it's a feature. I was pretty unhappy with the noise but there was nothing to be done. Sub itself is great so I didn't want to return it either. In the beginning of this year I read from the internet that SVS has made a second generation amp which is quieter. So I contacted my supplier asking if my amp could be replaced. They replied that they don't usually change amps since there was nothing wrong with the original but in this case they decided to make an exception. I just had to return the original amp at my own cost but that's nothing. Getting the new amp took little longer than I hoped. After about two months or so and some emails I finally got it. The new amp is definitely not dead quiet either but quieter than the old one. Now I can't hear the noise to my listening position which is very nice. So this case took longer than expected but the result was acceptable. Now I'm pretty happy with the sub. Here are some noise measurements I made from both amps.
- <1 from the woofer: 51 dB
- 12 from the woofer: 40 dB
- Background noise: 36 dB
- <1 from the woofer: 43 dB
- 12 from the woofer: 38 dB
- Background noise: 37 dB
I used class 1 SPL meter, Norsonic 131, but it's still pretty difficult to measure such levels since they are so close to the background noise. Still the new amp is less noisy. According to these measurements the original was also according to design (<50 dB @ 12) but I'd say it was still too loud.
Now I have a question for you guys. I'm not sure if this is the right place but let's try. Below is a picture of my set-up and REW measurements. I took frequency responses from all seats on my couch. Center seat, which is obviously the sweet spot, has a nasty dip at 30 - 60 Hz range. However, left and especially right seat have better FR. I would guess that the dip is caused by standing wave between side walls. So what do you think, would it help to have second sub on the left side of center speaker? I tried to put my sub in that place but FR was similar to current position. Does 1+1 equal 1 in this case? I have one old sub (REL Q150E) and I tried to make measurements with two subs but the old one is so different that I'm not sure if those results can be trusted. Any ideas how to get rid of that dip in my FR?Attachment 241335Attachment 241336