Crossover?

[Active Speaker]

Where should I crossover? My speakers only have 8 inch woofers, but they are flat down to 20 hz.

[Sorny]

Have you verified via SPL meter that your speakers are actually flat to 20Hz??? Try playing a tone at like 60Hz and try for around 80dB on the meter. Then, play a 20Hz tone and see how far down the output really is (remember to use the correction factor since the SPL meter is off down low).

The number of speakers that can actually play flat to 20 is pretty slim and can be counted on your fingers and maybe your toes. MANY speakers claim flat to 20, but most are being VERY "optimistic" (nice way of saying they lie through their teeth). Hell, most subwoofers can't do 20Hz with any authority...

Sorny

[Dudley]

I would start at a little higher than 80db, just to make sure low frequency backround noises etc have less effect on the lower readings. Also not the quality of the sound. When you are playing a 20 Hz tone is there a lot of port noise, or bottoming noise, or other distortion? This distortion can raise the level on the meter, even though it is not 20 Hz.

[Active Speaker]

I think that I perceived a "paper fluttering" sound at 20 hz, but it was definitely flat at 20 hz. I have two issues I'm currently dealing with: 1) I can't crank it up due to my wife & daughter sleeping (the only time I can even get to my system!), and 2) I have a buffered passive preamp which seems to limit the ultimate volume level of my system (although I have never tried to hit over 90 db because I just got a spl meter, & I never realized just how loud that actually is); I do all of my listening "nearfield", plus my room is fairly small anyway, so cranking it up is unnecessary.

[Rob Babcock]

80 hz is a good place to start. I won't argue if you say your speakers can go that low- a transmission line can give you bass that low with that size of driver, buy you aren't likely to be able to rattle the china. Dynamics will be a problem. Your speakers will be a lot happier if you filter that deep bass out- that will give you better dynamics and cut IM distortion way down.

If you don't listen really loud, you might even try X-ing over as low as 60 hz. This will minimize localization problems you might have with your sub. Hsu's are quite musical in addition to being very muscular- you shouldn't have any problem X-ing over as high as 80-90, but I wouldn't go any higher lest you begin to hear the sub distinctly.

[Active Speaker]

I believe that the normal crossover for the 500 watt amp is 51 hz; what do you think of that, Rob?