Not just a recommendation: actual mastering of 5.1 sound (120hz is the cutoff in content). I've got a big ole subwoofer and full range mains that get below 30HZ....but still have mixtures of center and surround speakers that can be measured just below 80hz. They still are in an environment folks say it's safe to add more padding in the bass extension. I would rather go above that and figure sound level....also phase adjustment can be a good factor as well (my subwoofer adjustment does have a dial for that....others can just have a switch).
Sub Bass?
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bigshot
Headphoneus Supremus
That’s just what my speakers recommended and the home theater sites I consulted said. It really doesn’t matter because 80 and 120 isn’t even an octave apart. You can set your crossover wherever you want.
The LFE channel is restricted to 120Hz but it has nothing to do with that being a recommended crossover point. In fact, that 120Hz cutoff was set (by Dolby) long before there was any consideration of consumer bass managed systems crossing over at 120Hz and simply because large commercial subwoofers would distort badly above that point.
Remember that a consumer bass managed system is a one way bass redirection. Freqs below the crossover point in the main channels are redirected to the LFE channel but nothing is redirected from the LFE channel to your main channels/speakers. Your subwoofer will play all the content/freqs in the LFE channel (up to the 120Hz cutoff), regardless of whether your crossover is set to 120Hz, 80Hz, 40Hz or anything else.
So where you set your crossover is entirely up to you, as bigshot says, although for best results, it should be dependant on the low freq performance of your main speakers.
G
71 dB
Headphoneus Supremus
Actually 120 Hz vs 80 Hz is a big difference! You need "twice as big" speaker enclosure to move the cut off frequency just a third octave. Also, the ability to hear the direction of the sound source at 120 Hz vs 80 Hz are different.
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samuelawachie
New Head-Fier
There are some gear and/or DSP software that do allow a user to low-pass the LFE though.
Even in foobar for instance, there’s a component Channel Mixer that has such options to high-pass mains and leave LFE intact, high-pass mains and low-pass LFE and full signal mains and bypass/full signal LFE.
There are options. I find that high-pass mains and low-pass LFE with satellite’s bass redirected to sub as well, works best for me. I set the low-pass filter to 80Hz
Even in foobar for instance, there’s a component Channel Mixer that has such options to high-pass mains and leave LFE intact, high-pass mains and low-pass LFE and full signal mains and bypass/full signal LFE.
There are options. I find that high-pass mains and low-pass LFE with satellite’s bass redirected to sub as well, works best for me. I set the low-pass filter to 80Hz
71 dB
Headphoneus Supremus
Except of course if a subwoofer isn't available (and configured OFF). Then LFE channel is redirected to the mains.
bigshot
Headphoneus Supremus
If your stereo is turned off no bass is directed anywhere!
That's a good way of putting it. The sub bass is more felt, but you really notice it when it is taken away. Some tracks will have a sub bass and a high bass in them
But why would you be using bass management to set a crossover frequency between your mains and subwoofer, if you don’t have a subwoofer?
G
71 dB
Headphoneus Supremus
Why indeed. You wouldn't, would you? I simply stated that one option for a system is to not have a subwoofer at all in which case the LFE channel is redirected to the mains.
sander99
Headphoneus Supremus
With my Yamaha RX-V771 - and many/most other surround receivers - I can set subwoofer off and the crossover frequency which in this case determines which frequencies from the center and surround channels (that are set to "small") are redirected to the main left and right speakers. I have large floorstanding mains and no subwoofer.
Obviously we were talking about bass management of a 5.1 system, not downmixing to stereo or some other system without a subwoofer.
G
71 dB
Headphoneus Supremus
Obviously bass management is needed regardless of what the system is. Nowadays 5.1 is just one option among many options. My own system is the "mid point" of 5.0 and 5.1 systems. The sub that goes to 25 Hz is passive and part of the mains with cut of at 50 Hz. I need to configure my system for a 5.0 system with very large mains. I have also set the cut off for center channel at 120 Hz and 60 Hz for rear speakers based on what gives the best soundstage cohesion, but all of this is for my speakers in my room acoutics with my speaker placement.
Obviously that’s incorrect. 5.1 was invented for cinema use without bass management.
Since the consumer release of 5.1, the vast majority listen to it down mixed to stereo. But I/we were specifically talking about 5.1 on at least a 5.1 system.
G
71 dB
Headphoneus Supremus
Well, in cinemas one isn't limited in regards of speaker system as one might be at home. Cinemas might do well without bass management, but I don't.
Why should I limit to what I am talking about according to what you are talking about? I would be parroting you adding nothing new to the conversation. Commercial 5.1 recordings is one thing, the speaker systems people have at home is another. To my understanding most people have pretty low quality speaker systems at home.
In real life people have God knows what speaker systems and there are various audio format available from mono to Atmos soundtracks. It is clear that without the possibility to configure the system properly there will be tons of problems. Most of my SACDs for example are not 5.1 but 5.0. LFE channel is for movies, not music.
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