using Sub as crossover (speakers)

[lawrence131]

Been looking for a small desktop amp to drive a bedroom 2.1 system and most of the popular ones only have stereo output. 
 
http://www.ebay.com/itm/SMSL-Q5-Pro-Pure-Digital-HiFi-Amplifier-USB-Fiber-Coaxial-Optical-Audio-Power-/221785133239?hash=item33a36c90b7:g:~mQAAOSw5ZBWH1bF
 
this one seems like a nice one with a lot of features including a sub-out, but I confirmed with manufacturer that even using the sub-out on it does not apply HPF for the front LR.  None of the sub-$300 small desktop amps I can find has built-in crossover features.
 
In general, is it better to use the speaker-level input and speaker level output of a decent sub to let it do the crossover for you if your amp can't do it?  The most popular desktop amps, even higher end ones tend to be stereo only since most users looking for portability are interested in just stereo output,  Or would it be better to use the sub-out on an amp like the one listed above and just let the speakers run full range and lose some power trying to push the frequencies already covered by the sub (<80hz).
 
i have a decent budget sub that has the built-in crossover with speaker level in and out to pair with this setup -  
 
http://www.newegg.com/Product/Product.aspx?Item=N82E16882290130&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-TechBargains-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=227502&SID=direct_cat_Newegg_0110_24202
 
(I wasn't even sure if the speaker in and out on these mid level subs were filter at all.  If you set the crossover at 80hz, does it set a HPF for the fronts or is it just a pass through when using speaker level input and output on these subs?).

 

[Wombats]

I have the exact same question with the exact same receiver/amp. It's such a shame the AD18 doesn't have crossover control of some kind. It would be 100% perfect.

Can somebody answer this question? For me specifically, I pre-ordered the ELAC B6.2 speakers. They go down to 44hz, but would they maybe perform better if they were filtered to 60hz or 80hz? Would it be worth passing through the subwoofer to get this crossover capability that is not provided by the receiver?

And also, do most subwoofers actually filter the output for the speakers, or just pass it through without any changes?

 

[Wombats]

Spent a bunch of money; found out the answer to this question the hard way.

• Most subwoofers do not do a high pass filter to the speakers even if the sub has speaker out plugs. My PL-200 II, for example, does not filter the speaker output. The crossover works only as a low pass filter for the sub. If I pass my speakers through my sub, I can adjust my sub crossover anywhere from 30hz to 100hz, but the speakers try to play full range no matter what. If you think your subwoofer has a high pass filter to the speakers; double check. It probably doesn't unless it's really fancy.
• The SMSL AD18 does not do any crossover or filtering of any kind. It outputs full range to the speakers and to the subwoofer. It's a real shame. I hope SMSL or some other company comes out with a receiver that does everything the AD18 does including crossover settings.
• A crossover setting is really necessary. I can run my ELAC speakers at full range and have the sub play up to 80hz and it sounds ok... but not amazing. You can hear when the speakers kick in and that specific part of the low frequencies get too loud. It's really best to have a good crossover setting with high-pass and low-pass if you can get it.

 

[Elecroestatico]

yeah subs dont cut the frequencies for the main speakers, most subs just let the entire full spectrum go to the speakers.