Hi,I am looking at two subs.The first one has a 80hz high pass filtered output,the second one has a high pass unfiltered output,both have adjustable low pass filter.Can you please explain what this means? It will be used for two channel not home theater.Thanks much!
It sounds like to me that the unfiltered high pass is implying that it doesn't implement a crossover for your main speakers. I've found it's best to cross your sub over as low as possible (40hz-60hz) and center your sub in between your speakers. What are the subs your are looking at?
The distinction is that the first will pass the signal to your main speakers after extracting the bass below 80Hz which is diverted to the sub while the second passes the full spectrum of signal to your main speakers. This applies only if you connect your main speakers through the sub's connections. Either way, both subs have the ability to filter (remove) the signals above the LP filter setting from being reproduced by the sub.

Which you might choose and what connection options you have (are all these ins/outs speaker or preamp level?) are dependent on what other components you have.
Thanks Kr4,the ins/outs are preamp to amp not speaker.The sub without the highpass filter has no speaker option.
B Limo,The subs are SVS model SB12-NSD and the SB-1000.
So, the high pass is line level RCA. That's good because speaker level would imply a passive iron core inductor. Also on that model, it has no speaker level inputs where the SB-1000 does. That means if you want to use high pass, you need cables to and from, which could be quite a distance and limitation.

Personally, I like the idea of using a high pass on the main speakers, particularly if they're smaller satellites, but this seems kind of awkward. Could be done more directly with a Harrison Labs FMOD and a Y-splitter or a MiniDSP 2X4.

Why I like a high pass is that it sometimes makes integration easier and, often, the mains just aren't that good at bass. Don't want to get too technical. Comes down more to variables and implementation than anything else.
Nice, Yogiboy! I have an svs sub also and love it. Svs makes great subs. What are your main speakers and how big is your room and how much bass do you want?

I like to run my paradigm studio 20's full range, not crossed over, and I set the crossover on my sub between 40hz-50hz. This set-up sounds great to me with perfect integration. If I set my crossover on the sub any higher, the sound becomes slightly muddied.

I prefer to run my main speakers full range as to not introduce another crossover to them, and I just want my sub to pick up where my mains drop off. I also prefer centering my sub between the main speakers because bass for me, is somewhat directional. Placing it in the corner of a room makes it louder but less accurate.

That sb 1000 looks like a great sub for the money, and in my opinion, sealed boxed subs are better for music. The don't have the sheer output of a ported design, all things being equal, but they provide a tighter bass.
You can make life a lot simpler by going the REL route. Connect it to the speaker terminals of the amp and adjust LP filter below which you want to pass on the signal exclusively to the sub(s), dial in the sub volume and phase setting and no need to fuss over a Xcrossover etc.
All the best
B Limo,I have Harbeth P3ESR'S.My room is about 500sqft.I ordered one today,they have a 45 day in home trial with full refund if I don't like it,it's a no brainer to try it out.Thanks much for the info.
Did you order the 1000? Nice speakers by the way. I think a sub will fill in the bottom end and that you'll be really happy. Try centering your sub, run your speakers full range, cross your sub over at 40-60 hz and don't turn your sub up too loud. It will be a subtle change but I think you'll like it. It should fill in the bottom bass notes and give you more depth to your soundstage while sounding seamlessly integrated. I'm looking into a n aurelex subdude. You might want to check them out too!
B LIMO,I ordrered the SB12-NSD,thanks for the info.