Crossover Frequency in Subwoofer

Wharfedale Diamond 12.1 & 12.2 Speakers

rsriramtce

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Hi

Please help me understand crossover frequency in subwoofers. What is that crossover frequency.
How to adjust them.
Also the same appears in my amp too. Should i change both to same amount for good hearing experience??

Crossover adjustment is available for all speakers in my amp. But available physically in sub??
 

Analogous

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Hi @rsriramtce,
This is a important question for anyone with a subwoofer.
A well set up sub can enhance our experience of music (and AV if used in home theatre). I personally feel getting high quality low frequency right is more difficult than for mids and highs.
I know friends who gave up using subs as they were not able to get the set up correct.
Cross over setting is one of the steps in the process. Getting the position of the sub in your room is often suggested as a good beginning. Once this is done the crossover and other adjustments can be done. (It took me several listening session over nearly three days to get it to where I was satisfied).
here is some guidance from REL (one of the masters of Subwoofer technology):
I am not familiar with Sub settings in amplifiers. But here is a nice article that explains crossover frequency settings:
(Apologies if you only wanted help with understanding crossover freq. and you already knew about the other parts of subwoofer set up.)
 

liverpool_for_life

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Hi

Please help me understand crossover frequency in subwoofers. What is that crossover frequency.

The crossover frequency is applicable only to bass-managed systems. As a general simplification, frequencies at or below the crossover frequency are handled by the subs, while those at or above it are handled by the speakers that are being bass-managed.

Effectively, a high-pass filter (at the cross over frequency) is run on a bass-managed signal which is then routed to the speakers and a low-pass filter (at the cross over frequency) is run on that same signal which is then routed to the subs. However, the crossover is not a brick wall. So, depending on the slope of the filters (how much the signal is attenuated per octave), you will still have frequencies above and below the crossover frequency going to the subs and the speakers.

How to adjust them.
Also the same appears in my amp too. Should i change both to same amount for good hearing experience??

The crossover should ideally be in your AVR/processor.

Crossover adjustment is available for all speakers in my amp. But available physically in sub??

I'd imagine this is for subs that accept a high-level input i.e. the signal to the sub is not bass managed.
 

edjamesx

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Hi

Please help me understand crossover frequency in subwoofers. What is that crossover frequency.
How to adjust them.
Also the same appears in my amp too. Should i change both to same amount for good hearing experience??

Crossover adjustment is available for all speakers in my amp. But available physically in sub??
If you are setting cross over in AVR , then you dont need to set cross over in Sub.
The cross over setting in Sub helps when you feed the signal with direct stereo or mono signal to Sub instead of dedicated Sub woofer connection from AVR.

You can switch off cross over settings on Sub if u have option / or set the same cross over setting as u do on AVR - generally its 80 hz.
 

rpmahale

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Cross over or cut off frequency which divide the audio signal in two parts where specialised speaker are use to reproduce audio signal . In more techchanical term, it is called as Bass management usually found in AVR. In 5.1 mode audio signal is encoded in six different channels . 0.1 is dedicated channels to handle additional low end information i.e. below 100 Hz of the sound track which need separate powered speakers called as active subwoofer. Active subwoofer have its own internal amplifier design to handle low frequencies efficiently. Earlier its use was up to handling just 0.1 information but now days AVR manufacturers have given the flexibility to divert the other channels low frequencies in Active subwoofer , All 5 channels contained the information from 20 Hz to 20 KHz but all five speakers are not able to produce all information due to design or physical constraints more specifically the low frequencies. So this part of audio signal from all channels with individual cross over points is diverted to Active subwoofer channel. Now Active subwoofer reproduces 0.1 signal along with this diverted low frequencies from all channels. Usually other five channels are cross over on 12 to 15 % more on -3 db low frequency limit of the individual speaker for strong and more enveloped surround sound effects.
Advantages.....
1. Releases or share the load from AVR and let the AVR to function more efficiently.
2. Rich low frequencies presentation
3. More exciting and involved movies watching experience .
4. Music have more low end weight.

Disadvantage...
1. Expensive to own
2. Difficult in integration and positioning
3. weak soundstage in stereo
 

rsriramtce

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If you are setting cross over in AVR , then you dont need to set cross over in Sub.
The cross over setting in Sub helps when you feed the signal with direct stereo or mono signal to Sub instead of dedicated Sub woofer connection from AVR.

You can switch off cross over settings on Sub if u have option / or set the same cross over setting as u do on AVR - generally its 80 hz.
Exactly
So when attaching directly to amp crossover setting is not used.the amp will manage the crossover to sub. If no amp then it is only for the speakers connected to the output of subwoofer if available. That’s understood. Thanks a lot
 

ankitbhargava

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Exactly
So when attaching directly to amp crossover setting is not used.the amp will manage the crossover to sub. If no amp then it is only for the speakers connected to the output of subwoofer if available. That’s understood. Thanks a lot
to make it simple
set the crossover frequency on Sub to max
set the crossover frequency to 80 hz (most common case) in AVR, test the system with various crossover points in AVR
 

sandeepmohan

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Adding my two cents on the subject after fiddling with my first sub woofer. Do note that this particular method is when you let the AVR do bass management. Some modern sub woofer brands let you electronically manage this from the plate amplifier controls on the sub woofer. Sub woofer connected using LFE input.

I am doing this on a old Denon 3312 AVR so some parameters while not labeled the same on other brand of receivers, can relate or match to something similar on your AVR settings. I had the sub woofer set to ON and not to Auto Stand by, as the sub woofer would switch off when the input voltage was too low from the LFE feed from the AVR.

My speakers are an old pair of B&W DM308 floor stands, a CC3 center channel and a Welling WS8 sub woofer. I do not have surround speakers.

I had my sub woofer gain set to the 12am position and the High Cut or Crossover set to max or 150Hz. Many have suggested this approach and its a good way to start.

I let Audyssey do its thing and then changed some parameters on the AVR later to over ride what auto calibration had done. My main speakers are crossed over at 60Hz (They can play down to 48Hz) and Center channel at 80Hz.

Denon AVR's allow for some finer control for bass under a category called "Bass" or "Bass Management" with parameters called Sub Woofer Mode and LPF for LFE. I set the former to LFE + Main and LPF for LFE at 80Hz. That is the lowest it goes for me. I did want my main speakers to handle some low frequency cause I know they can.

Audyssey set the sub woofer gain on the AVR at -10.5db. That's just 2 points above the lowest level, -12db.

My reference tracks were Oblivion for movies and Pearl Jam's Not for you and Nothingman track from the album Vitalogy. Both these tracks are not the best for exploring bass but they have enough bass on them to know if your sub is set up right. For me, it was familiarity with the movie and music that made me use these are reference tracks. You want to spend time listening.

When I first hit play, I was a disappointed. I could not hear the sub playing in the room. I tried to convince myself it was indeed playing but it was not. I checked the sub woofer driver and it was indeed vibrating. Just not audible, even if I turned up the gain a little more. I had left the gain at the 2pm mark. I then flipped the Phase to Reverse and wolla, we have bass. Now I could hear the sub but it was making its presence felt a bit too much. Ideally, it should disappear in the room, especially with music. Movies do have their dedicated .1 sub bass sound track which plays deep. This was audible too now. I slowly dialed the gain down a bit. It is closer to the 1pm mark now. I've not hit the sweet spot but I know I am close to it. A tiny bit further reduction in gain is probably all thats needed. Experiment with the sub woofer gain control and try with a wide range of music. Its alright if you want the sub to play louder at times, just don't let it take over the bass frequencies cause then it starts to boom and bloat. No harm in turning it up for some fun with movies.
 
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Analogous

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Adding my two cents on the subject after fiddling with my first sub woofer. Do note that this particular method is when you let the AVR do bass management. Some modern sub woofer brands let you electronically manage this from the plate amplifier controls on the sub woofer. Sub woofer connected using LFE input.

I am doing this on a old Denon 3312 AVR so some parameters while not labeled the same on other brand of receivers, can relate or match to something similar on your AVR settings. I had the sub woofer set to ON and not to Auto Stand by, as the sub woofer would switch off when the input voltage was too low from the LFE feed from the AVR.

My speakers are an old pair of B&W DM308 floor stands, a CC3 center channel and a Welling WS8 sub woofer. I do not have surround speakers.

I had my sub woofer gain set to the 12am position and the High Cut or Crossover set to max or 150Hz. Many have suggested this approach and its a good way to start.

I let Audyssey do its thing and then changed some parameters on the AVR later to over ride what auto calibration had done. My main speakers are crossed over at 60Hz (They can play down to 48Hz) and Center channel at 80Hz.

Denon AVR's allow for some finer control for bass under a category called "Bass" or "Bass Management" with parameters called Sub Woofer Mode and LPF for LFE. I set the former to LFE + Main and LPF for LFE at 80Hz. That is the lowest it goes for me. I did want my main speakers to handle some low frequency cause I know they can.

Audyssey set the sub woofer gain on the AVR at -10.5db. That's just 2 points above the lowest level, -12db.

My reference tracks were Oblivion for movies and Pearl Jam's Not for you and Nothingman track from the album Vitalogy. Both these tracks are not the best for exploring bass but they have enough bass on them to know if your sub is set up right. For me, it was familiarity with the movie and music that made me use these are reference tracks. You want to spend time listening.

When I first hit play, I was a disappointed. I could not hear the sub playing in the room. I tried to convince myself it was indeed playing but it was not. I checked the sub woofer driver and it was indeed vibrating. Just not audible, even if I turned up the gain a little more. I had left the gain at the 2pm mark. I then flipped the Phase to Reverse and wolla, we have bass. Now I could hear the sub but it was making its presence felt a bit too much. Ideally, it should disappear in the room, especially with music. Movies do have their dedicated .1 sub bass sound track which plays deep. This was audible too now. I slowly dialed the gain down a bit. It is closer to the 1pm mark now. I've not hit the sweet spot but I know I am close to it. A tiny bit further reduction in gain is probably all thats needed. Experiment with the sub woofer gain control and try with a wide range of music. Its alright if you want the sub to play louder at times, just don't let it take over the bass frequencies cause then it starts to boom and bloat. No harm in turning it up for some fun with movies.
@sandeepmohan, That’s a nice step by step guide to setting up a Sub. Your narrative brings out the fact that it takes some care and effort in setting up a subwoofer, but once you are there (or nearly there) it adds/brings a special magic to the audio experience and music that we did not realise was missing before. The extra effort needed to set a SW up may be one of the reasons many give up on SWs too soon. Your write up will hopefully help some FMs to persist and discover this special feeling.
It would help visualize your set up better if you could share the approximate size of your room and the placement of the SW relative to the floorstanders.
I take it that you did not have to move the sub around (room crawl) to find the best position as you used Audessey?
 

sandeepmohan

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@sandeepmohan
I take it that you did not have to move the sub around (room crawl) to find the best position as you used Audessey?
This is the best I can do.
Room Dimensions : 14ft*12ft*7.8ft (L*W*H)
Its your typical home setup. In my case its like a U arrangement and an open plan space so not a sound friendly setup. Floor is hard wood.
The sub woofer is in a corner but a good 1.5ft away from the wall, side and back. Bottom ported.
No, I did not do a room crawl. The sub is placed right beside the front right main speaker
Seating is 9ft away from the speakers.
 

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Analogous

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This is the best I can do.
Room Dimensions : 14ft*12ft*7.8ft (L*W*H)
Its your typical home setup. In my case its like a U arrangement and an open plan space so not a sound friendly setup. Floor is hard wood.
The sub woofer is in a corner but a good 1.5ft away from the wall, side and back. Bottom ported.
No, I did not do a room crawl. The sub is placed right beside the front right main speaker
Seating is 9ft away from the speakers.
@sandeepmohan, thanks for taking the trouble to draw this and post.
I can imagine the challenges of getting the best out of a open plan space. Most rules and measurements will not be applicable and it’s literally “going by the ear”
Good to know you are close to the sweet spot after your painstaking adjustments.
Enjoy the music!
 

Analogous

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Here is a very informative podcast on subwoofing from the designer of SVS Subs. He addresses all the questions I can imagine related to set up, integrating, room gain, placement, high and low level outputs, phase correction, standing waves, setting cross over frequencies, and more.
I found this really useful.
 

ssf

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This is what I have been following in my setup.

1. Stereo (Stereo amp with speaker level connections to subwoofer)

I set the subwoofer crossover to around 10 Hz higher then my speaker low frequency range. If my main speaker goes down to 45 Hz then I set the subwoofer crossover to around 55 to 60 Hz.

2. Home theater

I let the HT receiver manage the low frequencies. Set the speakers to small and crossover to 80 Hz. In the subwoofer, if there is a defeat, then at the defeat setting, else at the highest setting of the crossover of the subwoofer.

The LFE (Low frequency effects) .1 channel is only for movies. This has a frequency range of 120 Hz and below. Earlier, the thinking was that this setting should always be at 120 Hz as any setting below it will not be produced by the subwoofer and that range of information will be lost as it will not be redirected to any other speaker. But now a days, people are experimenting with this setting from 80 Hz to 120 Hz to see which suits them best.

I don't use LFE + Main, just LFE.
 

Analogous

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set the subwoofer crossover to around 10 Hz higher then my speaker low frequency range. If my main speaker goes down to 45 Hz then I set the subwoofer crossover to around 55 to 60 Hz.
I was doing something similar. Then I listened to the podcast above from the designer of SVS.
Somewhere in this he explains why this overlap of frequencies from the main speakers and SW causes undesirable effects.
I am thinking this man’s entire career and time is spent on subwoofers. He probably know a bit more than I do on thi
Now I am hunting specs of my speakers and hoping the manufacturer has been honest about the effective frequency range.
I intend to set the crossover frequency of the SW accordingly to minimize overlap and then fine tune by the ear.
I only use the SW in my stereo set up and with speaker level (full range signal) connection.
 

OM_2K19

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In my experience, setting the crossover between 100-120Hz yields the most optimal result in case you have a driver, less than 6" on LCR/Surround speakers.
 

ssf

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I was doing something similar. Then I listened to the podcast above from the designer of SVS.
Somewhere in this he explains why this overlap of frequencies from the main speakers and SW causes undesirable effects.
I am thinking this man’s entire career and time is spent on subwoofers. He probably know a bit more than I do on thi
Now I am hunting specs of my speakers and hoping the manufacturer has been honest about the effective frequency range.
I intend to set the crossover frequency of the SW accordingly to minimize overlap and then fine tune by the ear.
I only use the SW in my stereo set up and with speaker level (full range signal) connection.
I set it 10 Hz above speakers LF range as I am doubtful of the speaker going that deep in the room. I don't mind a bit of overlap but I don't want a frequency gap. Frequency overlap is another reason why LFE + main should not be set in a HT system.

Informative podcast. I have not read any other expert disagreeing with what is said in the Podcast.
 

sandeepmohan

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Frequency overlap is another reason why LFE + main should not be set in a HT system.
I suppose this is applicable if you have two independent systems or two pairs of speakers. In my case, my HT is my stereo too. In over 20 years of listening to music, this is the first time I introduced a sub into the system and boy oh boy is it amazing. I did try LFE only but the sub does not wake up and according to the Denon manual, says it may not operate. I do have the sub over lapping but not without the fronts doing what they can so I have them crossed over at 60hz cause I do want them to deliver bass. While they are specified to go down to 48hz, I don't know what they really do. All I can say they, they deliver good enough bass by themselves. What I have is a system that wows me and won't wow my friends for sure and I guess this will apply to many. My sub is not shaking the room when Hellboy is fighting with the green monster. It makes its presence felt from time to time and with stereo, it just about steps in to the point that you don't know its working. I love it.

I guess sub woofers and sound are a very personal thing. My settings or set up won't work for others. Some want room shaking, chest slamming bass and I get that. Most appreciate stereo without a sub. For me, the cinema is a 10 minute drive and no home theater beats that experience.
 

ssf

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I did try LFE only but the sub does not wake up
If fronts are set to large and LFE is selected, the sub will not get any signal. If fronts are set to large and LFE+Mains is selected, fronts will get the full range and the sub will get the signals from the point of the crossover.

I guess sub woofers and sound are a very personal thing.
Agree. If you know what your settings are doing and you are happy with the results, that is all that matters.

These days I don't use a sub for two channel music. On the rate occasion that a need for a sub is felt for music, I use the HT in Auro 3D. This is much better for music than the other formats available. But I still prefer the chain with the DAC and the pre-power to bookshelfs without the sub for music.
 
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