I'm picking up an old Rockford-Fosgate sub in a couple of days. It's a BNIB series 1 SPPR-128, 12 inches, 8 ohms, for 20 bucks. Just wondering if anybody knows anything about this sub, which is apparently from about 1991 or 92. Good score? Dumbass newbie?

I'm wondering if I should be a bit concerned about the 8 ohms thing. Won't I be reducing the effective power of my amp considerably, and maybe would I not be better off sticking to something 4 ohms? I'll be driving it with a pristine Kenwood KAC-718 mono sub amp, 120 watts RMS--also 20 bucks. I've got one of those little Bassworx sealed boxes, about 1 cu. ft. I think. That was 60 bucks, along with some blue Pioneer thing in it. I might be able to step up to 1.25 and still have a little trunk space (wife). There's a decent-looking Scosche one on Amazon for about 38 bucks, with free shipping to my new US delivery address just across the border on Wellesley Island. Can you tell I'm trying to do all this on a budget?

I'm not looking to "pound hard"; and the whole SPL thing seems kind of silly to me. I want to, you know, listen to music, with tight, articulate, appropriate bass, and to free up my front and back speakers from having to deal with low frequencies they can't reproduce, so they can devote all their energies to the frequencies they can. Isn't that what a sub is for? I guess that makes me an SQ guy, huh?

Anyway, any thoughts on this Rockford sub? Anyone?

 

If the kenwood amp does 12o at 2 ohms, you will barely get anything out of it at 8, you know that right? Might be an awesome sub, might be a really good amp, just not a good match up.

 

Specs on the amp say 120 RMS AT 4 ohms, 160 at 2...so I'm right to be concerned, then? Is there any way to like, rig up a dummy load or something to bring the overall impedence down to 4 or even 2 ohms? Or I guess get a bigger amp? Yowch, this is even worse than home audio.

Amp concerns aside, though, any views on whether this old RF is a good sub?

 

BTW having more power gives you more control of your speakers, by running them with lots of power at medium input volumes gives you less distortion. You will also want some kind of crossover system for your in car speakers, be it in your headunit/stand alone crossover/one thats built into your amp, so that you can control which frequencies go to each speaker. If you have an amp that will put out 100 watts at 4 ohms then you need to match a 4 ohm load to the amplifier so that you can get the best efficiency out of your system (and not have amplifier power that you paid for and aren't using)

My thoughts on the sub? Unless you get 2 you won't have anything less than an 8 ohm load... My guess is you could probably find a used sub in a box for 50-75

 

I did, actually. Some blue Pioneer thing in one of those little (~1 cu. ft.?) Bassworx boxes for 60. Just thought the RF sounded too good to pass up at 20 bucks. Any thoughts on finding a way to reduce the impedence the amp sees?

I also may have a line on a new Kenwood sub (not sure what model or anything). The lady who sold me the JBL tweeters with inline caps (9000Hz HPF I believe) for $30 (which I may or may not wind up using) says her husband has one. I offered 20, but no word back yet.

 

The only way you will get 160rms will be to find a 4ohm dual voice coil sub that is rated for small power and wire it to 2ohms.

 

Is the logo on the dustcap a solid red diamond with an R in it? Does it say Series 1 on it? IIRC the SPPR was the entry level woofer from RF at the time. Retail was $89-99. Try the Pioneer and then the RF and keep the one you like better.

 

Yep to both on the dustcap thing. It also appears to be dual voice coil. At least there are two hookups on the back. Or maybe they're just for convenience? How do I deal with that with a mono amp? Any effect on my impedence problem? And any thoughts yet on whether I can do anything to mimic another 8 ohm load? Maybe some resistors or something? Maybe there's even some way I can bring the whole works down to 2. I don't know, that's why I'm asking.

 

Might be a dual 4 ohm sub, that way u can get a 2 ohm load. Check it with a dmm and see what u got. Does it say anything on it referring to impendance?

 

Doesn't say anything that I can see. It's still in Trenton. But it is 8 ohms. That's apparently what the 128 stands for: 12 inches, 8 ohms. Plus the seller confirms it. Says he was planning to run 2 but never did.