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High-pass in sub to satellites not working? Or am i stupid? (B&W ASW600 sub)

Slyman

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Dear audioscientists

Today i tried experimenting with my 2.1 setup which consists of an B&W ASW600 subwoofer trying to get the bass settings correct. It looks like this:

asw600.jpeg


I just connect the sub by speaker wire from my amp, and the satellites through the sub. Anyways I found out to my big surprise that - although the manual states it - that it does not high pass to the satellites. How? By noticing that the low end of my satellites doesn't change volume at all while either turning the Low-Pass Filter knobs or by powering the subwoofer off. That is there seems to be no reduction of bass in my satellites whatsoever i do with the sub.

The problem is, that the manual clearly states that the output (both from speaker wire and line) is high-passed! And at this point i'm unsure wether i don't understand what a proper crossover is, or if my subwoofer is faulty.

I would think it goes like this in my setup with speaker wire: Full range from amp to sub -> sub playes below setting (lets say 80hz) -> 80hz+ get sent to the satellites. But i tested and there seemed to be no diminishment of bass frequencies whatsoever.

So now i'm really confused. Does the crossover simply not work and high pass properly? Or do i have a very naive understanding of how it should high/low pass? But then again what even is the reason for the manual and all the fuss if in the end the only option is to put the low pass where your satellites drop off manually?

Any help is appreciated!

PS. This even gets more stupid because my amp (NAD C326BEE) has subwoofer outs, which i guess is like just an RCA output below a random mid-bass hz freq, but still puts full range output through its speaker outputs... And now i'm not sure if i should just connect from the AMP to satellites directly with a RCA to the sub, or like i've done previously with speakerwire through the sub, the sub having the same configurations in both settings lmao.

So am i stupid? Is there kinda like a high-pass switch i can't see? Or is it that hard to find something that crossovers like you would expect it without getting a 20 kg receiver?

Edit: My satellites are Mission 753 floorstanders which are bass-light but goes down to 40 +-3 db still.
 
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DWPress

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I'm not exactly sure what all the switches like "EQ" and the "In/Out" do, the rest of your assessment is correct- that the sub should be implementing the high pass either with speaker wire or line in BUT:

You have the high pass filter set at 60Hz, can your satellites go down that low? Some smaller speakers even have a hard time getting down to 80Hz.
 
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Slyman

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I'm not exactly sure what all the switches like "EQ" and the "In/Out" do, the rest of your assessment is correct- that the sub should be implementing the high pass either with speaker wire or line in BUT:

You have the high pass filter set at 60Hz, can your satellites go down that low? Some smaller speakers even have a hard time getting down to 80Hz.
Thanks for your reply. My satellites are floorstanders that go down to 40hz +-3 db.
 

DVDdoug

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I just connect the sub by speaker wire from my amp, and the satellites through the sub. Anyways I found out to my big surprise that - although the manual states it - that it does not high pass to the satellites. How?
I'd guess the high-pass only works with line-level connections and the speakers connections just pass-through. A passive speaker-level crossover would have to be separate from the line-level active crossover.

Or is it that hard to find something that crossovers like you would expect it without getting a 20 kg receiver?
You can get an active crossover or a MiniDSP.
 
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Slyman

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I'd guess the high-pass only works with line-level connections and the speakers connections just pass-through. A passive speaker-level crossover would have to be separate from the line-level active crossover.


You can get an active crossover or a MiniDSP.
Well i thought so too but the manual states both in pictures of setups and on the last page that the speaker wire connection is high passed. But then it gets more spooky because is it then always high-passed the same indepedent of the frequency setting as long as the crossover i activated? In my mind the crossover should change so if i only listened to my satellites that if i turned the crossover from 60 up to 150 it would play much less bass/low-mid frequencies right?
 

DonH56

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@Slyman : The speaker-level high-pass connection does not use the active filters built into the subwoofer. The phase, frequency, and volume controls only affect the subwoofer in this case, so no effect on the speaker-level outputs. According to the manual (p70) the high-passed speaker-level output is a simple first-order 80 Hz fixed filter for 8-ohm speakers, which means it is probably just a single series capacitor of about 250 uF.

From the manual: High Pass Filter Speaker level: Passive 1st-order at 80Hz (8Ω load)

HTH - Don
 
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Slyman

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@Slyman : The speaker-level high-pass connection does not use the active filters built into the subwoofer. The phase, frequency, and volume controls only affect the subwoofer in this case, so no effect on the speaker-level outputs. According to the manual (p70) the high-passed speaker-level output is a simple first-order 80 Hz fixed filter for 8-ohm speakers, which means it is probably just a single series capacitor of about 250 uF.

From the manual: High Pass Filter Speaker level: Passive 1st-order at 80Hz (8Ω load)

HTH - Don
Ah beautiful. I tried googling 1st order high pass filters and must admit that i reached the boundaries of my audio knowledge in these searches. So does that mean that the satellites just get a "fixed filter" from 80hz? As in... like a one-size fits all shelf EQ preset that reduces lows?
 

DonH56

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Ah beautiful. I tried googling 1st order high pass filters and must admit that i reached the boundaries of my audio knowledge in these searches. So does that mean that the satellites just get a "fixed filter" from 80hz? As in... like a one-size fits all low EQ preset?
Yes, just a single setting, and it is even worse because it depends upon the impedance of your speakers at the crossover frequency. Speaker impedance (in ohms) varies wildly so without knowing exactly the impedance you cannot tell the exact crossover frequency. The Mission 753 specs say it is nominally 6 ohms, so the crossover frequency will be different, about 106 Hz if it is exactly 6 ohms. But I doubt it is exactly 6 ohms at that frequency... The only way to know for sure the actual crossover frequency is to measure your system.
 
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Slyman

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Yes, just a single setting, and it is even worse because it depends upon the impedance of your speakers at the crossover frequency. Speaker impedance (in ohms) varies wildly so without knowing exactly the impedance you cannot tell the exact crossover frequency. The Mission 753 specs say it is nominally 6 ohms, so the crossover frequency will be different, about 106 Hz if it is exactly 6 ohms. But I doubt it is exactly 6 ohms at that frequency... The only way to know for sure the actual crossover frequency is to measure your system.
Great. Thanks you truly are a don! I couldn't have hoped for a better answer.

May i perhaps ask lastly, that i see the "Line level: Active 3rd-order at 80Hz". Does that imply an active crossover using the line input/output that depends on (1) phase, (2) freq and (3) volume? Or is it just a similar a 3 bell EQ fixed at 80hz or likewise?

Edit: Or i can maybe rephrase would using the line level allow me to use the high-pass like you would expect in a crossover?
 
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DonH56

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Great. Thanks you truly are a don! I couldn't have hoped for a better answer.

May i perhaps ask lastly, that i see the "Line level: Active 3rd-order at 80Hz". Does that imply an active crossover using the line input/output that depends on (1) phase, (2) freq and (3) volume? Or is it just a similar a 3 bell EQ fixed at 80hz or likewise?

Edit: Or i can maybe rephrase would using the line level allow me to use the high-pass like you would expect in a crossover?
I do not know what "3 bell EQ" means.

To me, "active 3rd-order at 80 Hz" implies a fixed, third-order (18 dB/octave) high-pass filter at 80 Hz. So roughly -3 dB at 80 Hz, -18 dB at 160 Hz, -36 dB at 320 Hz, and so forth. It seems a little strange that it is not coupled to the low-pass filter but that's the way it reads. I did not read the manual carefully; it seems a bit hard to follow and leaves out details. It mentions setting the low-pass filter to match the response of you main speakers. The text to me implies that it does not affect the line out, but I am not 100% sure, and do not have any of this equipment. My read is that the frequency knob, phase switch, and volume knobs appear to be only for the input of the internal amplifier driving the subwoofer itself.

If you have active speakers, or the NAD has preamp out/power amp input jacks (I did not look), then you could insert the subwoofer's HPF in the loop to roll off the signal to the mains. E.g. preamp out -> subwoofer line in -> subwoofer line out -> main amp in. That would create the HPF side of an active crossover as you say, with the subwoofer's LPF providing the other (low) side.

I could not find anything in the NAD's manual about the sub outputs except they are there. :(
 
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Slyman

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I do not know what "3 bell EQ" means.

To me, "active 3rd-order at 80 Hz" implies a fixed, third-order (18 dB/octave) high-pass filter at 80 Hz. So roughly -3 dB at 80 Hz, -18 dB at 160 Hz, -36 dB at 320 Hz, and so forth. It seems a little strange that it is not coupled to the low-pass filter but that's the way it reads. I did not read the manual carefully; it seems a bit hard to follow and leaves out details. It mentions setting the low-pass filter to match the response of you main speakers. The text to me implies that it does not affect the line out, but I am not 100% sure, and do not have any of this equipment. My read is that the frequency knob, phase switch, and volume knobs appear to be only for the input of the internal amplifier driving the subwoofer itself.

If you have active speakers, or the NAD has preamp out/power amp input jacks (I did not look), then you could insert the subwoofer's HPF in the loop to roll off the signal to the mains. E.g. preamp out -> subwoofer line in -> subwoofer line out -> main amp in. That would create the HPF side of an active crossover as you say, with the subwoofer's LPF providing the other (low) side.

I could not find anything in the NAD's manual about the sub outputs except they are there. :(
Ok. Understood. Once again thank you very much for your advice! I guess coming from music production we're very spoiled in modern day DAWs when it comes to filtering and audio processing whilst audio hardware is a bit more hardcore!

Thanks for your input and knowledge. It really helped. Big respect!
 
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