Axiom Home Page Forums General Discussion Technical Questions Question about Subwoofer Cross-overs

My HK AVR125 has a fixed 100 Hz (at least I can find no way to adjust it) subwoofer cross-over. My question is this: does it make sense to buy a sub with an adjustable x-over (e.g., the EP175 I'm considering)? It seems to me that if I set it higher than 100 Hz, it wouldn't output anything at all since the receiver will only be sending it anything < 100. And if I set it lower than 100, I would effectively be filtering anything between that setting and 100. Thanks in advance.

double check the manual, cause i think you might be able to adjust the x-over. but not positive, so i could be wrong on that. but, you are right, if you adjust the sub x-over to anything under 100Hz, then you will just be "filtering" or losing the frequency inbetween.

and almost ALL subs will have their own x-over settings. the best thing to do is turn it to its highest setting, that way its internal x-over is basically taken out of the mix, and the x-over in the receiver will take over. so, to answer your question, "does it make sense to buy a sub with an adjustable x-over?".... YES, it does. like i was saying, they all have them, and it gives you more versatility for in the future in case you upgrade.

just remember to set the dial on the sub to its highest seting, and you will be good to go.

bigjohn

I think you may be confused about how the crossovers on the sub work. If you set the sub higher than 100 Hz (ie, 120 or 160 Hz), it will still be fed everything below 100 Hz by the reciever, and will not filter any of it. If you set the sub cross to below 100 Hz (say 60 Hz), it will filter out everything above 60 Hz (roughly speaking, JohnK), so you'd be missing out on the 60 Hz-100 Hz range. Basically, the sub crossover and the receiver crossover do the same thing, so you generally want to get the sub's out of the way by turning it up all the way.

OK, that makes sense. Thanks. As you guys suggested, I could take the sub x-over out of the mix by just setting it to > 100 Hz and be where I am today - just with a better sub.

And I'm pretty sure the AVR125 does not have an adjustable setting. The manual is pretty clear, and there is no setting I could find on the panel. This is going to prevent me from tweaking and finding the right mix with the M3s I plan to buy. Anyone know where the M3s tend to start rolling off?

>>Anyone know where the M3s tend to start rolling off?

Looks like -3dB somewhere around 70-75 Hz, although crossing over at 100 would actually give you smoother response. Here's a link to the response plots from a Soundstage review :

http://www.soundstagemagazine.com/measurements/axiom%5Fm3ti/

Couldnt he use the High Level inputs and get the crossover down to 80?