Cross Over Accuracy On Receiver

[Mlee]

Looking for some advice here please...

I have a Yamaha RX-V630 / 5560 receiver with Cerwin Vega AT-10's on the front - I have set all speakers to "small" and left the bass up to my STF-3. My issue is that I can hear test tones in the +125hz (up to 150hz) range comming from the STF-3, the Yamaha's manual suggests that the 90hz and lower material will be sent to the sub. I can also hear lower than 90hz (down to 40hz) in the mains which tells me that the receiver's cross over is not accurate. When I turn the sub's crossover to "In" it definately filters out the higher frequency sound and I think sounds cleaner...

This goes against the recommendations that I have read on this site, but in my case where the crossover seems to have much leakage on either side would it make sense to supplement with the crossover set to in?

[david_da_kine]

Crossovers are not "cliffs" - they attenuate something like 20dB per octave. For you 90 Hz crossove point, the sound will be reduced 20dB at 45 Hz (main speaker) and at 180 Hz (sub). It is normal to hear sound above and below the crossover point.

[Retread]

Originally posted by Mlee
Looking for some advice here please...

I have a Yamaha RX-V630 / 5560 receiver with Cerwin Vega AT-10's on the front - I have set all speakers to "small" and left the bass up to my STF-3. My issue is that I can hear test tones in the +125hz (up to 150hz) range comming from the STF-3, the Yamaha's manual suggests that the 90hz and lower material will be sent to the sub. I can also hear lower than 90hz (down to 40hz) in the mains which tells me that the receiver's cross over is not accurate. When I turn the sub's crossover to "In" it definately filters out the higher frequency sound and I think sounds cleaner...

This goes against the recommendations that I have read on this site, but in my case where the crossover seems to have much leakage on either side would it make sense to supplement with the crossover set to in?

I have a Pioneer VSX-D912 and have been running some tests using the Digital Video Essentials 6.1 full-bandwidth pink noise tracks and TrueRTA spectrum analyzer.

With the front and center speakers set to Large, the speakers disconnected, and the spectrum analyzer directly connected across the receiver terminals, I get a basically flat spectrum.

With the front and center speakers set to Small, I get a roll-off of 12 dB per octave, but there is a long knee beginning at about 200 Hz. At 100 Hz, the output is down about 5 dB, after which it takes the linear (with octave) slope. It's fairly common to specify roll-off at the -3 dB point, so these numbers would be consistent with that practice.

What the Yamaha does, I can't say, but I suspect they are specifying at the -3 dB point and have either a 12 or 24 dB per octave roll-off.