My Apologies to ComfyCurt and Others Who Helped in the Past: "R" Series Crossovers?

[Mike LoManaco]

I needed to look back for reference on the thread I had begun some time ago regarding the "R" series bookshelves and their crossover points, but couldn't find time to dig through the pages, so please forgive me...

'Curt and others who were assisting: You had said that keeping my R20 mains, CSi center and R15 surrounds ALL on "80Hz" crossovers inside my Onkyo '605 was okay, did you not? Right now, all three speaker suites are crossed over at "80" in the Onkyo, with the "Low Pass Filter of LFE" on "120Hz" for maximum bass output -- is it okay to leave all of these on 80Hz?

[apphd]

I don't remember the thread you are talking about but since 80 Hz is a good starting point for most speakers, and so many others here gave you that freq. I would say yes to your question but think the 120 Hz on the sub is a little high. When you are listening to your set up do you hear the bass? In such a way you could point to the sub and say it is coming from there. You should have the sub set up so it blends with the rest of your speakers to a point you know it is there, but can not locate where it is coming from.

[kuntasensei]

120Hz is the ONLY proper setting for the LPF of LFE, since the LFE channel is spec'd for a 120Hz brickwall filter. Setting it to anything below that is truncating data from the LFE channel. That setting has zero effect on the redirected bass from the other channels, so it won't affect localization; you just won't be filtering out the harmonics in the LFE channel above 80Hz.

[apphd]

Thanks for more info kuntasensei. Wouldn't this depend on how the sub is connected to the AVR whether the subs LPF or the AVRs is being used? i.e sub connected via speaker level inputs and sub "off" in AVR wouldn't you want to use the subs LPF?

[messiah]

You can always do as apphd has said, and use the sub as the crossover. Use the Frequency adjustment on the back of the sub to dial it in. If you have more questions, just ask.

[kuntasensei]

Thanks for more info kuntasensei. Wouldn't this depend on how the sub is connected to the AVR whether the subs LPF or the AVRs is being used? i.e sub connected via speaker level inputs and sub "off" in AVR wouldn't you want to use the subs LPF?

The LPF of LFE setting on the AVR only affects the LFE channel. It is not a global low pass; that's controlled on a per-channel level by the crossover settings of the individual channels. The only time LPF of LFE should be set to 80Hz is for THX-spec'd subwoofers that aren't designed to reproduce anything above that. Onkyo sets LPF of LFE to 80Hz by default to maintain THX compliance, and this setting is NOT changed during any auto-setup, since there's no way to detect for it. It's simply a legacy of THX specifications.

A low pass filter on the subwoofer itself, on the other hand, affects everything you're sending to the subwoofer. The analog LPF on a subwoofer can also induce delay, which can throw off the proper distance setting of your subwoofer in the AVR. If you're using the crossover settings in the AVR at all, you should be turning the LPF on the subwoofer to its maximum setting to both get it out of the way (so you don't cascade the filters on the AVR and sub and create a gap in response) and to prevent any filter-induced delay.

Regardless, it's a minor niggle. There won't be a huge amount of audio in the LFE channel above 80Hz anyway and whether you notice a difference between 80Hz and 120Hz LPF of LFE settings depends greatly on the quality of your subwoofer and how critical a listener you are. However, setting the LPF of LFE to 80Hz needlessly truncates audio in a channel that is already brickwall filtered at 120Hz by its very nature (which is why it's the .1 in 5.1/7.1; it only holds 1/10th of the full bandwidth of the other channels). It will not be more or less localizable with either setting, but setting it to 80Hz will remove the above-80Hz harmonics placed in the LFE channel by the audio engineers, and these harmonics are largely what lends bass its perceived tone.

[Mike LoManaco]

I don't remember the thread you are talking about but since 80 Hz is a good starting point for most speakers, and so many others here gave you that freq. I would say yes to your question but think the 120 Hz on the sub is a little high. When you are listening to your set up do you hear the bass? In such a way you could point to the sub and say it is coming from there. You should have the sub set up so it blends with the rest of your speakers to a point you know it is there, but can not locate where it is coming from.

Thanks App,

That "120Hz" setting is NOT a crossover frequency for the sub -- it's a setting that Onkyo uses on their receivers for "filtering out" hum in the LFE signal and such...120 is the default factory setting, and from what I understand, the setting is correct at this value as the other member mentioned; the "LPF" stands for LOW PASS FILTER...

As for the other speakers, are you saying keeping all of them on 80Hz is okay?

[Mike LoManaco]

120Hz is the ONLY proper setting for the LPF of LFE, since the LFE channel is spec'd for a 120Hz brickwall filter. Setting it to anything below that is truncating data from the LFE channel. That setting has zero effect on the redirected bass from the other channels, so it won't affect localization; you just won't be filtering out the harmonics in the LFE channel above 80Hz.

That's what I thought, Kunt; supposedly, Onkyo recommends not touching this setting unless bass localization is really apparent or there is some unwanted hum from the LFE signal...

So, 120Hz should be left alone, yes? (For LPF of LFE)

[Mike LoManaco]

The LPF of LFE setting on the AVR only affects the LFE channel. It is not a global low pass; that's controlled on a per-channel level by the crossover settings of the individual channels. The only time LPF of LFE should be set to 80Hz is for THX-spec'd subwoofers that aren't designed to reproduce anything above that. Onkyo sets LPF of LFE to 80Hz by default to maintain THX compliance, and this setting is NOT changed during any auto-setup, since there's no way to detect for it. It's simply a legacy of THX specifications.

My Onkyo is not a THX certified model -- Onkyo sets the LPF of my model to "120Hz" as default...

A low pass filter on the subwoofer itself, on the other hand, affects everything you're sending to the subwoofer. The analog LPF on a subwoofer can also induce delay, which can throw off the proper distance setting of your subwoofer in the AVR. If you're using the crossover settings in the AVR at all, you should be turning the LPF on the subwoofer to its maximum setting to both get it out of the way (so you don't cascade the filters on the AVR and sub and create a gap in response) and to prevent any filter-induced delay.

Regardless, it's a minor niggle. There won't be a huge amount of audio in the LFE channel above 80Hz anyway and whether you notice a difference between 80Hz and 120Hz LPF of LFE settings depends greatly on the quality of your subwoofer and how critical a listener you are. However, setting the LPF of LFE to 80Hz needlessly truncates audio in a channel that is already brickwall filtered at 120Hz by its very nature (which is why it's the .1 in 5.1/7.1; it only holds 1/10th of the full bandwidth of the other channels). It will not be more or less localizable with either setting, but setting it to 80Hz will remove the above-80Hz harmonics placed in the LFE channel by the audio engineers, and these harmonics are largely what lends bass its perceived tone.

So, are you saying leave the LPF of LFE setting where it is on 120?

[kuntasensei]

80Hz is good for all of your speakers. And yes, leave LPF of LFE at 120Hz, for the reasons I previously stated. The hum thing that Onkyo stated is a non-issue, since most subwoofer hum would be 60 cycle noise from poor power or a ground loop problem, which the LPF of LFE wouldn't correct anyway.

Typically, I recommend that people set their per-channel crossovers at least a half-octave above each speaker's lower -3dB point. You can find the lower -3dB point of each speaker in Polk's specs, then multiply that number x 1.5 to get a general idea of where the best crossover point is. However, with your particular speakers, that point is going to pretty much be near 80Hz... which is fine, considering setting it any lower would just further tax your 605's amp section and setting it any higher increases the odds of localizing the subwoofer (by passing significant audio above 80Hz to the sub). Also, using different crossovers for various channels introduces its own issues with room integration, so it's usually best to stick with one setting for all channels unless you want to get REALLY anal about placement/distance/EQ'ing.

[Mike LoManaco]

80Hz is good for all of your speakers. And yes, leave LPF of LFE at 120Hz, for the reasons I previously stated. The hum thing that Onkyo stated is a non-issue, since most subwoofer hum would be 60 cycle noise from poor power or a ground loop problem, which the LPF of LFE wouldn't correct anyway.

Thank you!

Typically, I recommend that people set their per-channel crossovers at least a half-octave above each speaker's lower -3dB point. You can find the lower -3dB point of each speaker in Polk's specs, then multiply that number x 1.5 to get a general idea of where the best crossover point is. However, with your particular speakers, that point is going to pretty much be near 80Hz... which is fine, considering setting it any lower would just further tax your 605's amp section and setting it any higher increases the odds of localizing the subwoofer (by passing significant audio above 80Hz to the sub). Also, using different crossovers for various channels introduces its own issues with room integration, so it's usually best to stick with one setting for all channels unless you want to get REALLY anal about placement/distance/EQ'ing.

Thank you, again!

So, 80Hz across the board it is, and 120Hz on LPF...:)

[comfortablycurt]

That's what I thought, Kunt

LMAO! That may not be the best way to abbreviate kuntasensei's name.;):p



Personally, I find 80hz to be a much better XO point for the sub in my system. With it set higher I found that too much information was coming through the sub, and in some instances, even dialogue(think James Earl Jones).

With your speakers set at 80, and the sub set at 120, it could create an undesirable boost in the 80-120hz range, since both the speakers and the sub are reproducing those frequencies.

You're the one listening to it though, so you've got the last call on it.;)

[kuntasensei]

Curt... I think you're misunderstanding what LPF of LFE is. It ONLY AFFECTS THE LFE CHANNEL. There's no "undesirable boost" whatsoever, because he is using an 80Hz crossover for all the main channels regardless. In other words, if all his channel crossovers in the AVR are set to 80Hz and LPF of LFE is set to 120Hz, the AVR filters all the other channels except the LFE channel at 80Hz then sums this together with the unaltered LFE channel for output to the subwoofer. You can set LPF of LFE to anything you want and it won't change the 80Hz crossover of the other channels one jot. It definitely doesn't alter dialogue, because there's no dialogue in the LFE channel.

A lot of people make the mistake that LFE equals "subwoofer". LFE is the low frequency effects channel. There is no LFE OUTPUT on any AVR, just a subwoofer output, which is the sum of the LFE channel AND redirected bass from the other channels (which is what's controlled by the per-channel crossovers).

As for "the speakers and the sub are reproducing those frequencies", that's ALWAYS the case in the crossover range. Crossovers aren't a sudden transition from speaker to sub. Typically, the crossover point is the point where the speaker and subwoofer are outputting that frequency in equal amounts. For example, if you set a channel's crossover to 80Hz, any 80Hz sound you play will be coming 1/2 from that channel and 1/2 from the subwoofer. That's why you always want to set your crossover slightly above the speaker's lowest significant output (which is why I recommended a half-octave rule above to give room for a smooth transition with no gap in frequency response). Even with an 80Hz crossover, your speaker is producing some sound at 50Hz, albeit reduced as the bass is handed over to the subwoofer. Likewise, the subwoofer is reproducing audio above 80Hz, albeit at a reduced level that, when summed with the bass from the channel itself, creates a flat response (which is why proper distance settings in your AVR are so important - to keep the subwoofer and other channels in phase so there's no cancellation). The speed of this transition is called the crossover's slope. Look up Linkwitz-Riley filters for more information on how one transitions to the other.

This is why it's important to set the crossover/LPF on your subwoofer itself to its highest setting - to get it out of the way so the crossover in the AVR can provide a smooth transition. A lot of people make the mistake of thinking "I set the crossover on my receiver to 80Hz, so the one on the subwoofer also needs to be 80Hz." This creates a problem known as crossover cascading, where you're essentially filtering the crossover range twice, creating a huge gap in response. DON'T DO THIS.

So, long story short, it's as I said before: The only RIGHT way is 80Hz crossovers for all the main channels, LPF of LFE at 120Hz, crossover on the subwoofer turned to its maximum (both to get it out of the way so it doesn't cascade with the AVR's filters, and to prevent filter-induced delay that will throw it out of phase with the other channels). It will not create any boost in the 80-120Hz range, and in fact will PREVENT a reduction of sound in that range.

[comfortablycurt]

I understand prefectly well what the LFE is.

When the main speakers are crossed at 80hz, and the subwoofer at 120hz though, they are both reproducing those frequencies without any rolloff. They're both coming through strong, at full signal. In my personal experience, this creates a very undesirable boost in the 80-120 range.

Also, I have definitely heard dialogue through my subwoofer with the XO set higher. My girlfriend and I were watching The Lion King sometime back, which has James Earl Jones as the voice of Mufasa. We were cracking the hell up because Mufasa's voice was coming through the subwoofer and pounding on the floor...lol

I've tried my setup with the sub set at 120hz, and I found it to sound utterly terrible. With 80hz across the board, it sounds fantastic. I don't think there is a "right" or "wrong" setting, as you're suggesting. Everyones setup, and personal tastes are going to vary. If there was a right or wrong setting, it would be fixed, and wouldn't be adjustable. It's adjustable so that people can tailor it to their own tastes.

[reeltrouble1]

when I saw the title of this thread I gotta say I felt a bit ill.

carry-on.

RT1

[Mike LoManaco]

LMAO! That may not be the best way to abbreviate kuntasensei's name.;):p

LOL...LOL...you're right! But I totally meant no harm by it; I was merely abbreviating the name...

Personally, I find 80hz to be a much better XO point for the sub in my system. With it set higher I found that too much information was coming through the sub, and in some instances, even dialogue(think James Earl Jones).

With your speakers set at 80, and the sub set at 120, it could create an undesirable boost in the 80-120hz range, since both the speakers and the sub are reproducing those frequencies.

You're the one listening to it though, so you've got the last call on it.;)

Well, as K. said, the LOW PASS FILTER setting is different from the main channel crossover settings -- I know 120 should be left alone in the LPF area, but all the other speakers in the system I am wondering if they should be set to "80Hz" all around for rolloff, as you originally suggested....

[comfortablycurt]

Well, the suggestion of leaving it at 120 goes against basically everything I've ever read on the subject. In my experience it sounds like crap with it set that high. Do what sounds best to you, but I'd suggest you experiment with different XO settings for the sub.

The standard suggested setting for LPF that I've ALWAYS read is 80hz. It's been the best in my setup as well. I'm still failing to see how that setup isn't going to create an undesirable boost in the 80-120 region. With the HPF of the speakers set at 80, and the LPF of the sub set at 120, you have both of them reproducing those frequencies. This is going to make that region a lot louder and muddier sounding.

[kuntasensei]

When the main speakers are crossed at 80hz, and the subwoofer at 120hz though, they are both reproducing those frequencies without any rolloff. They're both coming through strong, at full signal. In my personal experience, this creates a very undesirable boost in the 80-120 range.

WRONG. The rolloff is handled by the CROSSOVERS on the AVR being set at 80Hz. It isn't just a high pass filter. Data above 80Hz in that case is not being sent to the subwoofer "at full signal". With a Linkwitz-Riley crossover (which is what crossovers in AVRs are designed to emulate), in the crossover range you're both reducing the amount of audio in the channel itself and increasing the amount in the subwoofer as frequency drops. The crossover slope determines the speed at which this transition is made. Linkwitz-Riley crossovers ensure that frequency response remains flat as this transition is made, with the crossover gradually handing off the bass to the subwoofer without any phase reversal that would cause cancellation. If you set your AVR's crossovers to 80Hz and then also apply the low pass filter on the subwoofer's amp at 80Hz (not the LPF of LFE), you are reducing audio from about 50-100Hz that is SUPPOSED to be reproduced by the subwoofer to prevent gaps in frequency response. Applying a second filter on the subwoofer simply MURDERS frequency response across the crossover range, and will give you at least a 3dB drop at 80Hz (which essentially halves the sound that SHOULD be there). It may sound good in your room because of room-induced acoustic issues... but it's still, on a very simple and technical level, WRONG.

Also, I have definitely heard dialogue through my subwoofer with the XO set higher. My girlfriend and I were watching The Lion King sometime back, which has James Earl Jones as the voice of Mufasa. We were cracking the hell up because Mufasa's voice was coming through the subwoofer and pounding on the floor...lol

You might have heard dialogue through your subwoofer because of the acoustics of your room or phase cancellation issues (which can be caused by improper distance settings or poor phase alignment between the subwoofer and other speakers). In your room, you're cascading the filters to correct a perceived boost in frequency across the crossover range... which is fine for you, because it's your system. It doesn't change the fact that if you're having to use the LPF on the subwoofer to fix that problem, the root cause is your speakers themselves not producing the proper amount of bass in that range of frequencies as the transition from the other channels to the subwoofer occurs.

I've tried my setup with the sub set at 120hz, and I found it to sound utterly terrible. With 80hz across the board, it sounds fantastic. I don't think there is a "right" or "wrong" setting, as you're suggesting. Everyones setup, and personal tastes are going to vary. If there was a right or wrong setting, it would be fixed, and wouldn't be adjustable. It's adjustable so that people can tailor it to their own tastes.

I'm not arguing that on YOUR system, it doesn't sound better. Your room has its own unique combination of speaker placement, acoustic issues, reflections, etc. that will alter the sound, plus you have your perception of how it SHOULD sound. It's your system - set it up however you want. But if someone comes here to the forum and asks what the right way to do it is, THERE IS A RIGHT WAY TO DO IT. This is why we have guidelines to recreating the intended audio in the home environment, and why mixing studios are so carefully phase and time aligned and set to industry standards. The recreation of this in the home is the goal.

You want to start with the proper settings first and then do critical evaluation of your room's acoustics. Cascading the crossover in the AVR with the LPF on the subwoofer creates so many system integration problems that there is no way in hell he will get flat response across that range... unless by some million-to-one miracle his room has the exact acoustic signature for that to work. For him to find out, he should set things up the way you're supposed to - the way dictated by very basic acoustic principles determined by how crossovers work, both in AVRs and in your speakers themselves (and I hardly think you would argue that the crossover in your speaker that transitions from tweeter to woofer is reproducing all frequencies in that range the way you're implying they would in the AVR/sub setup). Giving bad advice that goes against this very basic audio theory based on the acoustics of YOUR individual room and speaker placement is just bad form.

But I ain't mad at ya', Curt! Do what you gotta' do! Though if you have a SPL meter, I could send you a disc of test tones that would totally show you the nightmare situation you're creating by cascading a third filter on top of the AVR's crossover (which is already a high-pass/low-pass filter configuration).

[kuntasensei]

Here are a few resources, so you don't have to take my word for it:

From Polk: "If your subwoofer does not have an LFE input, use either the L or R line input (a Y splitter is optional) then turn the "low pass" control as high as it will go." Source.

From Bigpicturesound: "If your home theater receiver or processor allows you to adjust the crossover settings independently for your speakers, then generally speaking, you should use the crossover settings in your receiver or processor and set the subwoofer's own "crossover bypass" control to "bypass" (assuming it has one)." Source.

From Axiom Audio: "But you do want to set the subwoofer’s crossover to its maximum rotation so you remove it from the circuit. This is done to avoid "cascading" two crossovers, which might cause uneven and erratic deep bass output. . .The only occasion where you will need to use the subwoofer’s built-in crossover control is when you are not using a line-level "Sub Out" connection from an A/V receiver." Source.

From Secrets Of Home Theater And Hi-Fi: "The crossovers of "Bass Management" are exactly that: crossovers. The signal sent to the subwoofer does not magically stop at a given frequency, and vice versa for the speaker. The output of the two cross over each other. As with the crossover from a tweeter to a woofer, the summation of the two components must be correct if we want any semblance of high fidelity." Source.

Look at the charts here to understand how crossovers work for subs and what the LFE channel is.

From Dolby Labs: "So, generally, what I've told people is, if you've set the bass redirection up properly in the receiver, and there's nothing but a crossover point, just a dial, just make sure it's all the way up, and then you can't go wrong." Source.

[kuntasensei]

Also, from p. 45 of the Onkyo TX-SR605 manual: "If the subwoofer has a low-pass filter switch, set it to Off or Direct."

[Mike LoManaco]

But does this conclude that I should leave the speaker crossovers at 80Hz across the board on the 605 and the LPF of LFE on 120?.....:(

[comfortablycurt]

Dude...I have an SPL meter. My response is pretty flat across the board. That's why it's setup the way that it is.;)

As you said though...attribute it to room acoustics.

The fact still remains though, that this is THE FIRST time I have ever heard anyone make the suggestions that you're making.

[kuntasensei]

Dude...I have an SPL meter. My response is pretty flat across the board. That's why it's setup the way that it is.;)

Yes, but only for your room... and because of the way you're doing it (essentially using the low pass on the subwoofer as an EQ to fix room-induced frequency problems), you're truncating the LFE channel and likely throwing out bass from several of the other channels. You're using the sub's LPF, which is very broad in bandwidth (and likely a 24dB/octave slope) when you should be using a parametric EQ to precisely correct your subwoofer's in-room response independently from the other channels. You're also throwing off the proper distance/delay setting of your sub by layering another filter on top of the existing crossover in the AVR, which can alter phase. This is why the crossovers in AVRs are designed to mimic analog Linkwitz-Riley filters - they minimize phase issues/cancellation as the transition from one driver to the other occurs.

There are three potential causes of your problem that you should have checked into before messing with the LPF on the sub:

1) Your sub is out of phase with your center channel, causing cancellation somewhere in the crossover range that biases the sound toward the sub (and causes bass in dialogue to localize to the sub). To check, set your crossovers to 80Hz and LPF on the sub to its maximum then play test tones from 50-100Hz and write down the SPL levels. Then, flip the sub's phase switch (or reverse it 180 degrees if you have a variable phase control) and re-run the tones. Leave it on the phase setting that gives you the strongest response near 80Hz. You can also bump subwoofer distance up and down and re-run the tones to see if a different delay gives you better phase correlation between the center and sub.

2) You've got a nasty room-induced null near the crossover range (~80Hz) for at least your center channel that is causing you to perceive more bass from the subwoofer than you should. The only way to test for this is with bass sweeps/test tones encoded to each individual channel so you can assess each speaker's frequency response. Dialogue issues are typically center channel issues. I have a DTS-CD that I mixed and encoded with test tones in each of the channels so I can assess each channel on its own and compare to tones in the LFE channel only so I can see cancellation on a per-channel basis.

3) Instead of using the LPF on the sub, try turning the crossover for the center channel down a bit. Though 80Hz is a good guideline, if you've got room-induced reinforcement or nulls, you can mitigate localization problems by reducing that individual channel's crossover. If your AVR allows, try 70 or 60Hz for the center and run bass sweeps to see if that smooths out response. Doing so is preferable to using the sub's LPF because the digital crossovers in the AVR exhibit no phase shift, whereas the analog LPF on the subwoofer can alter phase. By correcting the response of one channel with the sub's LPF, you may be destroying the phase relationship with the sub and the other channels.

[kuntasensei]

But does this conclude that I should leave the speaker crossovers at 80Hz across the board on the 605 and the LPF of LFE on 120?.....:(

Yes, for your speakers, 80Hz is a good crossover point and the LPF of LFE on the AVR should ALWAYS be set to 120Hz unless you're using a THX-certified subwoofer which is designed for THX spec'd performance (as one of the Secrets articles above should have confirmed). Any good subwoofer should give you consistent response up to at least 120Hz so it can support the other channels, which is necessary even with the other channels crossed over at 80Hz. Older AVRs didn't give you the option, instead low-passing the entire subwoofer output globally based on the other crossovers (so if you set even a single channel to 50Hz, it low-passed the entire summed output at 50Hz, throwing away most of the LFE channel in the process). AVRs with independently adjustable crossovers and LPF of LFE don't exhibit this problem, so you can properly pass the entire LFE channel to your sub and still cross the other channels over at a lower non-localizable frequency.

Still, as I've said before, the difference between 80Hz and 120Hz LPF of LFE settings will only be noticeable on maybe 5% of content, since most audio mixers tend not to put info above 80Hz in the LFE channel. This setting doesn't affect sound redirected from the other main channels AT ALL.

[comfortablycurt]

Just to be clear, I'm not using the LPF on the sub. I'm using the LPF on the AVR. The AVR's LPF is set to 80, and the LPF on the sub is turned all the way up to get it out of the signal path.

I'd be interested in getting a disc with these test tones on it. Where might I get one?

[kuntasensei]

Just to be clear, I'm not using the LPF on the sub. I'm using the LPF on the AVR. The AVR's LPF is set to 80, and the LPF on the sub is turned all the way up to get it out of the signal path.

I'd be interested in getting a disc with these test tones on it. Where might I get one?

So you know... if you're hearing any difference in dialogue bass by changing the LPF of LFE setting, it's completely psychoacoustic. You're hearing it because you think you should. The AVR's LPF of LFE does not filter the bass redirected from the other channels or the entire global summed output as it is passed to the subwoofer pre-out; IT AFFECTS JUST THE LFE CHANNEL, and it does so BEFORE the other channels are summed together and sent to the subwoofer out. You can set it to 80, 100, 120... won't change bass redirected from the center channel (or any other channel than the LFE channel) by a single decibel.

I never found a retail disc with per-channel 20-120Hz tones, which is why I mixed and encoded one myself. You could, however, verify what I'm saying if you have Avia, since its test tones are located in the main channels and it has 40-80Hz band-limited tones for each channel (which would show you that LPF of LFE doesn't alter the level of the test tones at all).

[megasat16]

Mike, you must be hell of confused. I know I am. And it came from the guy with 8 subs in the same room. :D

I wanted to follow what you guys are saying but I give up. I don't understand the LPF of the LFE.

LPF = Low Pass Filter (Frequency).

LFE = Low Frequency Effects (known as the sub channel)

So, if you set a frequency for the LFE channel, I think it can simply be called LFE frequency? What difference does it make to call it LPF of LFE?

Just to make simple things simple and complex things simple, use the same frequency at your AVR for the speakers to be the same as that on the LFE channel (i.e. if you don't want your speakers playing over 80Hz, use the Crossover frequency for that speaker at 80Hz, all the frequency below 80Hz will be passed to the LFE channel.)

At your LFE channel, you can either set 80Hz or a little more or less such as 70/75Hz to 85/90Hz (just play with it). But you should not set the frequency too lower (such as 60Hz / 50Hz in LFE channel) from your Speaker Crossover Frequency because you'll be losing most of the information between that two frequencies and thus creating a gap in sound.

If your subwoofer has the frequency dial, you can set it to higher or all the way up or (use bypass) than what's being set on your LFE to make sure it'll play what's coming from LFE channel.

[megasat16]

Just to be clear, I'm not using the LPF on the sub. I'm using the LPF on the AVR. The AVR's LPF is set to 80, and the LPF on the sub is turned all the way up to get it out of the signal path.

I'd be interested in getting a disc with these test tones on it. Where might I get one?

Curt, there are test tones CD on the net. Google "Test Tone CD". AVS has a thread about it.

[kuntasensei]

I wanted to follow what you guys are saying but I give up. I don't understand the LPF of the LFE.

LPF = Low Pass Filter (Frequency).

LFE = Low Frequency Effects (known as the sub channel)

I cut the rest to illustrate where the problem we're having in this thread may lie. LFE does equal Low Frequency Effects. It's the .1 in 5.1/6.1/7.1 surround, named .1 because that channel takes 1/10th of the bandwidth of the other channels. LFE does NOT equal "sub channel" and is completely independent of the subwoofer output on your AVR.

The only time that the subwoofer output sends only the LFE channel to your sub is when all other channels are set to FULL RANGE (i.e. no crossover in your AVR). If any of the channels are crossed over in the AVR, the redirected bass from those channels is combined with the LFE channel (which is given a +10dB boost during decoding) and then the sum of this is passed to the subwoofer output.

"LPF of LFE" is Onkyo's term for a low pass filter in the AVR that is applied ONLY to the LFE channel on a digital level before this channel is summed with managed bass to be sent to the subwoofer output.

Just to make simple things simple and complex things simple, use the same frequency at your AVR for the speakers to be the same as that on the LFE channel (i.e. if you don't want your speakers playing over 80Hz, use the Crossover frequency for that speaker at 80Hz, all the frequency below 80Hz will be passed to the LFE channel.)

Nope. As stated above, the LFE channel is designed to carry 1/10th of the bandwidth of the other channels (usually stated as 20Hz-120Hz, where Dolby applies a brickwall filter... though the LFE channel often carries bass below 20Hz). The ONLY way to pass this entire channel without cutting any of it off is to set LPF of LFE to 120Hz.

At your LFE channel, you can either set 80Hz or a little more or less such as 70/75Hz to 85/90Hz (just play with it). But you should not set the frequency too lower (such as 60Hz / 50Hz in LFE channel) from your Speaker Crossover Frequency because you'll be losing most of the information between that two frequencies and thus creating a gap in sound.

Setting the LPF of LFE below the crossovers of the other channels will NOT lose any information from the other channels or cause frequency gaps from those channels. It will only reduce the level of audio placed in the .1 channel of the mix. All redirected bass, as determined by the other channels' crossovers, will be passed through unaltered no matter what you set LPF of LFE to on the receiver.

If your subwoofer has the frequency dial, you can set it to higher or all the way up or (use bypass) than what's being set on your LFE to make sure it'll play what's coming from LFE channel.

This is sort of true, but you're still confusing "LFE" with "subwoofer output". The two are not the same thing.

[megasat16]

I cut the rest to illustrate where the problem we're having in this thread may lie. LFE does equal Low Frequency Effects. It's the .1 in 5.1/6.1/7.1 surround, named .1 because that channel takes 1/10th of the bandwidth of the other channels. LFE does NOT equal "sub channel" and is completely independent of the subwoofer output on your AVR.

The only time that the subwoofer output sends only the LFE channel to your sub is when all other channels are set to FULL RANGE (i.e. no crossover in your AVR). If any of the channels are crossed over in the AVR, the redirected bass from those channels is combined with the LFE channel (which is given a +10dB boost during decoding) and then the sum of this is passed to the subwoofer output.

"LPF of LFE" is Onkyo's term for a low pass filter in the AVR that is applied ONLY to the LFE channel on a digital level before this channel is summed with managed bass to be sent to the subwoofer output.

Nope. As stated above, the LFE channel is designed to carry 1/10th of the bandwidth of the other channels (usually stated as 20Hz-120Hz, where Dolby applies a brickwall filter... though the LFE channel often carries bass below 20Hz). The ONLY way to pass this entire channel without cutting any of it off is to set LPF of LFE to 120Hz.

Setting the LPF of LFE below the crossovers of the other channels will NOT lose any information from the other channels or cause frequency gaps from those channels. It will only reduce the level of audio placed in the .1 channel of the mix. All redirected bass, as determined by the other channels' crossovers, will be passed through unaltered no matter what you set LPF of LFE to on the receiver.

This is sort of true, but you're still confusing "LFE" with "subwoofer output". The two are not the same thing.

Ok, I am going to give it a shot to see what I am missing.

During Remastering of the movie, LFE is encoded into the normal 7 channels as it would appears to be in real life. Now, if you have all Full Range Speakers, all speakers could be set to Large and plays the entire frequency for each 7 channel (i.e. from 20Hz to 20KHz) and you can turn the subwoofer channel OFF.

You don't need to connect .1 channel or subwoofer to get any LFE effects if you have all 7 full range speakers?

What you are saying is that movies have LFE from all channels (below 120Hz) combined and encoded 10dB HOT into the sub channel (.1 channel)?

Now, I am confused as Hell since you are saying this is done at the remastering and not by the AVR? I think it's done by the AVR based on how you set it up?

I think that's why the AVR lets you either turn the Subwoofer out (for LFE based on whether you used Large or Small Speakers) to be either turn on or off. But I guess it's an AVR dependent feature.

Actually, I am not confused about LFE and subwoofer output. I said LFE out = subwoofer out for those who don't have opportunity to use LARGE setting or full range speakers. When they use small speakers (small setting) in the AVR, LFE encoded into mains, and surround channels are passed down to the subwoofer channel (.1 channel) based on what speaker channel is set to LARGE or SMALL and what crossover frequency is set for that channel.

I am not famaliar with Onkyo term for LPF of LFE. It's very confusing when you have Low Pass Filter setting for Low Frequency Effect when I think it can simply be called Low Pass Filter Frequency or LFE frequency for subwoofer.