Bypassing passive speaker subwoofer?

[Gackt]

Hi,

So I'm saving up for subwoofer upgrade (PB/SB 2000 SVS), but in the meantime, I already have two vintage subwoofer, Cerwin Vega SW-12B and HT-10D) both are enough for now.

This two subwoofer have big crossover inside. I know for a fact that recapping the crossover can sometime improve/fix the sound. My Wharfedale 9.6 was missing treble, change the cap, voila, the speaker sing again.

But before I recap this subwoofer, I have an idea to just bypass the crossover. I'm using Denon X1400H for my home theater, and I think the two sub out from Denon already sending a proper signal (bass) so I should be able to by pass the subwoofer crossover right? Sending a direct signal from Denon x1400h sub out -> amplifier (which is a vintage amplifier, 100watt, 10-50khz response frequency) -> subwoofer (without crossover).

Thoughts? Thanks

 

[homebrew]

If you bypass the crossover in the sub, you'll be feeding a full range signal to the subs and the satellite speakers. While a passive crossover is better than none at all, the best solution is a separate outboard active crossover, and power amplifiers for the sub woofers. Since you say you're savings for an SVS sub (wise choice), best sit tight and keep what you have.

 

[Gackt]

If you bypass the crossover in the sub, you'll be feeding a full range signal to the subs and the satellite speakers. While a passive crossover is better than none at all, the best solution is a separate outboard active crossover, and power amplifiers for the sub woofers. Since you say you're savings for an SVS sub (wise choice), best sit tight and keep what you have.

Thank you for your reply. I don't see why X1400H would feed full range signal? Is the Subwoofer out feeding the full range signal? If this the case then you are right. But I always assume that the subwoofer out on AVR actually only out certain range ( the bottom rest of the crossover set up from initial set up).

 

[spark1]

Thank you for your reply. I don't see why X1400H would feed full range signal? Is the Subwoofer out feeding the full range signal? If this the case then you are right. But I always assume that the subwoofer out on AVR actually only out certain range ( the bottom rest of the crossover set up from initial set up).

Yes, sub-out is not a full range signal. And I don't see how doing what you are planning would affect "satellite" speakers.

That said, if your subwoofer(s) have a variable low pass crossover, losing it might make blending with your main speakers more difficult.

Also, I would verify the sub-out filter frequencies in the manual for your AVR.

 

[Stuart Pedaso]

Hi,I already have two vintage subwoofer, Cerwin Vega SW-12B and HT-10D) both are enough for now.

But before I recap this subwoofer, I have an idea to just bypass the crossover. I'm using Denon X1400H for my home theater, and I think the two sub out from Denon already sending a proper signal (bass) so I should be able to by pass the subwoofer crossover right? Sending a direct signal from Denon x1400h sub out -> amplifier (which is a vintage amplifier, 100watt, 10-50khz response frequency) -> subwoofer (without crossover).

Yes, that should work.

Your Denon's two line level sub outputs have configurable low pass frequency settings ranging from 80Hz to 250Hz. Configure and feed those outputs to an external stereo amplifier to power the subs and you no longer need the subs' internal crossovers.

A couple of things to consider.

If your main speakers are larger and you want full range from them while augmenting low bass with the subs, set subwoofer mode to "LFE+Main." That ensures the sub line level outputs will send an audio signal for the subs in all circumstances. Otherwise set your main speakers to "small."

Also if you want to feed both voice coils of each CV subwoofer from the external amp, it will need to be stable into 4 Ohms.



Alternately, you can connect the voice coils in series if need be.

 

[Gackt]

Yes, that should work.

Your Denon's two line level sub outputs have configurable low pass frequency settings ranging from 80Hz to 250Hz. Configure and feed those outputs to an external stereo amplifier to power the subs and you no longer need the subs' internal crossovers.

A couple of things to consider.

If your main speakers are larger and you want full range from them while augmenting low bass with the subs, set subwoofer mode to "LFE+Main." That ensures the sub line level outputs will send an audio signal for the subs in all circumstances. Otherwise set your main speakers to "small."

Also if you want to feed both voice coils of each CW subwoofer from the external amp, it will need to be stable into 4 Ohms.

View attachment 2163667

Alternately, you can connect the voice coils in series if need be.

Thanks for confirming, clear as a day. Your image is spot on, but I'm acctually using two amplifier, so each amplifier driving 1 passive sub. No particular reason, I just have old amp lying around and their response frequency is not bad 10hz-40khz so they should be able to reproduce whats coming in from denon x1400h. Thanks again!

 

[opnly bafld]

@Gackt

No reason to bypass the crossover, the CV low pass is high and has a shallow slope, it will just supplement the low pass from the Denon's sub out.

 

[homebrew]

Thank you for your reply. I don't see why X1400H would feed full range signal? Is the Subwoofer out feeding the full range signal? If this the case then you are right. But I always assume that the subwoofer out on AVR actually only out certain range ( the bottom rest of the crossover set up from initial set up).

Didn't register you were running the sub from an AVR sub out that's probably fixed at 80 hz. Brain fart!

 

[spark1]

Didn't register you were running the sub from an AVR sub out that's probably fixed at 80 hz. Brain fart!

Not fixed. See above.

And in most cases, subwoofers don't play a role in filtering the signal to the main (satellite?) speakers. High-pass filters in subwoofers are not the norm.