Do adjustments in subwoofer crossover frequency affect subwoofer out?

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    Sam R.

    The Crossover setting will set the cutoff for the audio going out of the SUBW OUT. 

    IF you have the Settings > Player > Audio > Subwoofer switch set to ON, this cutoff point is applied to the main outputs as well (the rolloff you described)

    If this Subwoofer setting is OFF, the mains are unaffected by the Crossover setting. 

    Regards,
    Sam R.

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    Scott Beall

    Thanks for reply. Glad that the sub output is adjustable as well. What slope is the crossover? 

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    Sam R.

    12dB

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    Gglendon

    This is interesting. I didn't know the BLUOS affected both the sub-out and mains-out. So am I right in thinking that it really is instituting a complete cross-over between the main speakers and sub. Am I also correct in thinking, that as long as the sub's own cut off frequency is a higher frequency than that of the BLUOS setting, that further fine tuning of the sub could just be limited to its overall volume? I am thinking of getting a REL T 7X for use with the new POWERNODE that I have on order. 

    Gord G.

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    Craig

    I too find that interesting. I am still not sure I have the outputs and filtering correctly understood. I was under the impression that you cannot do anything to the subwoofer output. It is always on and always full frequency range with volume tracking with the BluOS volume control. If that is so you need to make adjustments directly on the subwoofer (gain/volume and frequency cutoff point.

    If that is true then I understand the subwoofer switch and frequency selection in BlueOS is only going to affect the mains output. It will adjust the low frequency point at which the mains will rolloff their output therfore releleaving the mains amplifier output from being used for the low frequencies being handled by the subwoofer.

    In the end if that is true and you are driving your subwoofer from the mains output youshould never select subwoofer on in BluOS as you will restrict bass information getting to the subwoofer.

    Looking for clarity.

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    Sam R.

    I'll try my best to clear it up. 

    Am I also correct in thinking, that as long as the sub's own cut off frequency is a higher frequency than that of the BLUOS setting, that further fine tuning of the sub could just be limited to its overall volume? I am thinking of getting a REL T 7X for use with the new POWERNODE that I have on order.

    Shouldn't affect volume, just the frequency cutoff. Typically volume and crossover adjustments are exclusive to one another (depends on design, but volume would be amplifying the voltage and crossover would be filtering through an analog electronic filter)

    Short answer: applying a crossover to an already crossover'd signal should not affect volume quality

    I was under the impression that you cannot do anything to the subwoofer output. It is always on and always full frequency range with volume tracking with the BluOS volume control. If that is so you need to make adjustments directly on the subwoofer (gain/volume and frequency cutoff point.

    Partly. The SUBW OUT of the BLS player is always fired up, but will not send full range - it is adjustable from 40Hz to 200Hz (at an early time it was hard set at 80Hz only, but now that is just the default).

    [...]the subwoofer switch and frequency selection in BlueOS is only going to affect the mains output.

    The Subwoofer switch will affect only the Mains out. The Frequency adjustment will affect the mains ONLY if the Subwoofer switch is on. The Frequency Adjustment will always affect the SUBW OUT. 

    In the end if that is true and you are driving your subwoofer from the mains output youshould never select subwoofer on in BluOS as you will restrict bass information getting to the subwoofer.

    This just piqued my interest. I don't know if you could really run the sub on the mains of a BLS player. Perhaps NAD (but the SUBW OUT design on an NAD amp is usually different), but the POWERNODE isn't designed to run a sub via the speaker terminals and you'll likely get a ground loop if you try. 

     

    TL;DR: 

    Subwoofer (On/Off) only affects the Main RCA or Speaker out. Set to ON will apply a high pass filter to the RCA and Speaker Out based on the crossover freq set. Leaving this in the OFF position will send full range out of the RCA and Speaker Outs. The SUBW OUT output (nor digital outputs on the NODE/VAULT) will not be affected by this

    Crossover adjusts the crossover point, between 40Hz and 200Hz. Anything below your set crossover will be sent out of the SUBW OUT of your player (active at all times). Only if the Subwoofer switch is set to ON, will the RCA/Speaker Out be affected (high-pass filter applied). 

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    Scott Beall

    That cleared up several points for me, but created one new one. So the subwoofer crossover “ON” setting does not affect the digital output? The crossover is applied only following DAC conversion and in the analogue domain and affects the RCA analogue main outs only? So digital out gets full range signal? I am using an external DAC/Active bookshelf and supplementing it with the subwoofer out to a separate active sub.

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    Craig

    Sam R. - you really cleared things up very nicely.

    Re - I don't know if you could really run the sub on the mains of a BLS player. Perhaps NAD (but the SUBW OUT design on an NAD amp is usually different), but the POWERNODE isn't designed to run a sub via the speaker terminals and you'll likely get a ground loop if you try.

    I should have specified this meant driving a powered subwoofer like a Bowers & Wilkins that can be driven with speaker level inputs. You hook it up to speaker output on the Powernode and continue from the speaker output on the subwoofer to the main speakers. In this case the subwoofer switch would be off on the Powernode and the subwoofer would be adjusted with the crossover and gain control directly on the subwoofer. 

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    Sam R.

    Scott - that's correct, digital outputs are unaffected by subwoofer switch, full range all the time (and unaffected by Tone Controls as well - we try not to make any changes to the digital outputs to the goal of providing digital content out as original as possible) 

    Craig - ah. Now that you mention it I have come across that before, once. 

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    Gglendon

    Wow, This is crazy. I love my Bluesound products but the lack of clarity in the documentation about how to use the sub out is difficult to understand. I assume Bluesound like to have a very minimal approach to the product to make it user friendly but I think there needs to be a dedicated FAQ or something from Bluesound about this. Is there any additional documentation other than "its a 12 DB crossover? Also, I assume the filter is DSP?

    But to sum up, let's be as clear as possible....

    1) The sub-out has a continually operating low pass filter that is set at the frequency indicated on the crossover setting and sub output is always on.

    2) The mains-out has a high pass filter applied to it when the sub setting is toggled "on" and its frequency is indicated by the crossover setting. 

    3) Digital out is always pure signal regardless of crossover or sub setting.

    Can someone from Bluesound confirm?

    Cheers,

    Gord

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    Jason Chiovitti

    So this doesn’t seem to be the case with the NAD M10 and I wonder if it is true about the C658 (on the way). With the M10 there is most definitely zero signal to the sub from the sub out RCAs when “No Subwoofer” is selected in the BluOS audio menu, and selecting 1 or 2 subs in the same menu does indeed low pass the sub and high pass the mains. I wish there was an option to Augment the sub bass, low pass the sub out but send full frequencies to the mains.

    Additionally, with other DSP crossovers there’s usually a low pass selectable frequency and a high pass selectable frequency so that you don’t cross both at the same freq. Doing that sums the levels at that frequency causing a bump. I assume BluOS’s crossover is taking this into account however?

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