Summary: Unbelievable sub. I have had crazy systems in the past. This sub paired with the alpine 6x8 two ways in four doors and alpine tweeters in the front. All run off the alpine 5 channel v9. I had a custom down firing box built for it that fits UNDER half of my back seat. Wasn't really expecting a lot.
Summary: Very impressive shallow mount subwoofer. I am NOT a fan of alpine subs normally. This driver is however a cut above the other subs Alpine offers. It is very clean and accurate. It also has very good output.
Summary: I have a 2012 Chevy Malibu and had an Alpine SWR-12D4 in a full size sealed box that took up half my trunk space. We've had a new addition to our family and soon realized the box and the baby stuff was not all going to fit. I needed something smaller but still wanted some thump.
Summary: Well I can't say its the company fault but I got a swr-t12 with a cracked magnet / heat sink. So I took pictures never plugged it in and I got to wait a ~2 weeks for it to clear up and got another one. It sounded mediocre (in sealed box of ~0.8cu ft) Powered by a moderate Alpine PDX-M6.
Summary: I would not even compare this to a standard type r. I bought this for truck. It lasted maybe two months. After it blew on the song Late Night Tip, the speaker was dented. Looked like someone had punched it in.
Summary: For a thin single 12 inch sub I'm extremely happy with the performance. I installed it behind the seat of a crew cab F350 in a custom made box. I matched it with an Alpine PDX-5 amp on the sub channel, it has plenty of power!