I'm experimenting with a bi-amping setup. The active crossover used is an a/d/s/ 642ix car electronic crossover. It has a feature that allows it to feed subwoofer signal, i.e. bass lower than 80 Hz filtered by subwoofer channel low-pass, to main speakers. The main speaker is a floor-standing type with two 10-inch woofers per side. The subwoofer signal would be set to MONO operation. My question is whether I need to use a "band-pass" filter on the woofers of the main speaker. Or can I use the main speaker as a full-range speaker? Because the subwoofer signal is set to mono and will be fed to the main speakers, I'm concerned that the stereo bass of the woofers and the mono bass of the subwoofer signal will interfere with each other.
System configuration:
(A) Run the main speaker as a full-range.
Tweeter = 5 k - 20 kHz
Midrange = 500 - 5 kHz
Woofer = 20 - 500 Hz
Subwoofer (fed to the woofer) = 20 - 80 Hz
(B) Apply a band-pass filter to the woofer.
Tweeter = 5 k - 20 kHz
Midrange = 500 - 5 kHz
Woofer = 80 - 500 Hz
Subwoofer (fed to the woofer) = 20 - 80 Hz
Which option should be chosen? Please advise.
System configuration:
(A) Run the main speaker as a full-range.
Tweeter = 5 k - 20 kHz
Midrange = 500 - 5 kHz
Woofer = 20 - 500 Hz
Subwoofer (fed to the woofer) = 20 - 80 Hz
(B) Apply a band-pass filter to the woofer.
Tweeter = 5 k - 20 kHz
Midrange = 500 - 5 kHz
Woofer = 80 - 500 Hz
Subwoofer (fed to the woofer) = 20 - 80 Hz
Which option should be chosen? Please advise.
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Two questions...
Why would you fed subwoofer signal back to main speakers? Liberating the main speakers from low frequencies reduces their distortion. You are trying to do the opposite.
Whats wrong with mono subwoofer? Below certain frequency, 80hz for sure, bass is not localized, as our head is too small, resp.ears too close. Two satelites with one sub works just fine. There is benefit in having multiple subs, but that is totally unrelated.
Why would you fed subwoofer signal back to main speakers? Liberating the main speakers from low frequencies reduces their distortion. You are trying to do the opposite.
Whats wrong with mono subwoofer? Below certain frequency, 80hz for sure, bass is not localized, as our head is too small, resp.ears too close. Two satelites with one sub works just fine. There is benefit in having multiple subs, but that is totally unrelated.
Are the main speakers as capable as the sub in the 20-80hz region? If so the you would effectively have 3 subs in the room all in different locations, that can work well and help smooth out the response but it can also create exactly what you don't want.. a hole in the response at the listening position if you don't have the option of moving all the "subs" around the room to thier ideal locations.
One of the benefits of adding a sub to a system is to take the load of reproducing those LF frequencies away from the main speaker, this usually allows them to play louder and/or cleaner, and with a separate sub you can position it in the room for best LF response in the listening position without compromizing the stereo image from the mains.
One of the benefits of adding a sub to a system is to take the load of reproducing those LF frequencies away from the main speaker, this usually allows them to play louder and/or cleaner, and with a separate sub you can position it in the room for best LF response in the listening position without compromizing the stereo image from the mains.
The best way to send lowest frequencies to main amps and speakers starts with not removing them in the first place.
The active crossover has this feature. So, I’d like to try it.
I’m afraid that the main speakers themselves reproduce stereo bass. Feeding mono bass to the main speakers may cause interference, something like bass cancellation. I’m not sure.
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Yes, the main speakers can reproduce bass as low as 28 Hz.
I believe you have misunderstood. I don't have a subwoofer in my system. However, the active crossover allows me to use the main speakers to reproduce bass instead of subwoofers.
What is the source of the sub-woofer signal?
If, it's derived from the L/R signals then just disable the subwoofer band pass ( or ignore it ) and run the woofers down to 20Hz... that is, apply only the 500 hz low pass filter to the woofers. There really is not much to be gained by mono'ing the bass signals across both main L/R speakers, IMHO. Use the crossover as a three way, not a four way.
If, OTOH, the subwoofer signal it's derived from a different input channel, as in LFE, then run (a).
To emphasize bass. The output of the main speakers will consist of its own bass and the addition bass from the low-pass filter.
I guess a high shelf filter at 80Hz, implemented on both channels to the main system, would bring what you want, without concerns about mixing mono and stereo signals. But if you'd want to use the sub out (I really wonder why), you have to sum the mono line signal properly with both stereo signals. That, to me, would require a stereo buffer stage summing amp. A low impedance (relative to the input of the amps) resistor summing network, in order not to introduce crosstalk in the stereo signal, could work depending on the output power of your active crossover. Still, to me that makes no sense.
This is interesting.
I still wonder that if I mix the mono bass, the subwoofer signal, with the stereo bass, the main speaker’s woofer, will they interfere each other and cause something like bass cancellation, or destroying stereo image?
Of course, both signals will be summed. Anything up to + or - 120 deg phase shift will cause no real problem, more will lead to gradual cancellations. And since the circuit will be voltage-driven, two full level signals will just deliver one full level signal. If one signal e.g. is 6dB higher than the other, the sum will be that of the higher.
Most music ís recorded mono under about 100Hz anyway, apart from SFX in the (re)mix. So as long as you use the buffer stage, I see no real problems.
Most music ís recorded mono under about 100Hz anyway, apart from SFX in the (re)mix. So as long as you use the buffer stage, I see no real problems.