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How do I set the crossover for 2 channel listening on my HT system?

My system consists of a Denon HT receiver powering a pair of B&W 805S speakers (and, unrelated to this question, B&W center channel and surround speakers) with a vintage M&K MX-350 THX subwoofer fed through the receiver’s LFE output via single subwoofer cable. In 2- channel mode the receiver is set for L/R front and subwoofer play only, using the Denon’s “Direct/Stereo” play mode. The signal is fed to the receiver via RCA interconnects from a stand-alone streamer (Bluesound Node 2i) and DAC (Topping D90).

The 805S speakers have an advertised frequency range of 49Hz–22kHz ±3dB. The subwoofer has a variable low pass filter adjustment ranging from 40 to 100Hz. The receiver’s speaker set-up settings allow a crossover setting in steps from 40 to 250Hz. The subwoofer’s phase adjustment has been properly set.

I understand a subwoofer crossover should roughly match a speaker’s low frequency capability, i.e., in my situation the M&K low pass should be set at approximately 49Hz. (I say roughly because the subwoofer crossover frequency is listed at +-6db whereas the speakers is at +-3db). But what effect is the crossover setting on the receiver having and where should it be set for 2-channel listening in my situation? Is the HT receiver’s subwoofer crossover setting controlling the signal to the subwoofer and either cancelling out or somehow multiplying the subwoofer’s independent crossover setting.   

sadbird
sadbird OP
22 posts
 

To bjp9738: Thank you for the clarification that the Denon crossover settings fo not apply to the LFE channel. I was concerned I was mutiplying or contradicting the settings if both the Denon's and M&K's were in play.

Based on what you said, if I am only listening to 2-channel stereo (thus only employing the FL/FR speakers and subwoofer and not the remaining surround sound speakers) there  apparently is no base management being used in the Denon. Under this circumstance I assume I should NOT set the low pass on the M&K to its highest setting but instead find an appropriate setting sounding best with the front speakers. Do I have this right?

(Also presumably when reverting to HT and using all speakers your advice to set the M&K high would then apply.)

bjp9738's avatar
bjp9738
64 posts
 

@dsands You didn’t say which model you have, but in most Denon AVR’s, if you have your Fronts set to Large, bass will never be sent to the subwoofer unless you set the subwoofer mode to LFE+Main, or you set the Fronts to Small. I do not believe there is any way to engage the subwoofer in the Denon and NOT use the Denon’s crossover settings.

So I think your best approach might be to set Fronts to Large, set sub mode to LFE+Main, and then set a crossover point of either 40Hz or 60Hz in the Denon for your Fronts and leave the M&K’s low pass at its max.

sadbird OP
22 posts
 

bjp9738:

Thanks for beng so generous with your time and information. The fronts are set to large and I'll follow your guidance regarding the settings on the receiver and sub and--to take a line  from russ69 above--set the sub to its max and then make any slight  adjustment until it sounds right.

I appreciate everyone's input. 

james633
889 posts
 

No matter how large my speakers are (cruelty my mains have two 8” drivers) I always crossover (highpass) at 60hz or more. I have found subs to be much better than anything short of super speakers below 60hz. 70-80hz will depend on the speakers/room as at 70hz and above tone of the sub comes more into play as it need to match the speakers. For small speakers like the 805 I feel 70hz is a good place to start but for most speakes 60hz is the magic number with a 24db slope.

trying to come in under you speakers without a highpass from the receiver will not be optimal. Also keep in mind the port is out of phase with the drivers so as you crossover higher the phase could change a bit.

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