Will this xo give me all the LFE's for movies?

[derrickdj1]

First, a little background on the subwoofer, if all speakers are set to small and the xo is lower than 80, does this effect the LFE? The Surround Sound Processor recieves a full range copy of all the speakers set to small, sounds OK. If the mains and center are xo at 40 and 100 for an extreme example, then all of the .1 info in the copies of the channels set to small have some of the .1 info thrown away. In this example, the info from 40 to 120 Hz is thrown away from the main channels that were low passed and so on for any channel with a xo of less than 80 Hz.

THX experimented with various xo's and came up with 80 Hz? THX determined that the 4th order xo of 80 Hz was good since there is little LFE from 80-120 Hz. I had to ramble this around my head a few times because I thought a xo of 40 was in the best interest of my big tower speakers. Now it seems like holes all over the place depending on the xo. Now the difference between the center and the mains leave a hole of 60 in the front stage. The front three channel in the system normaly recieve all the same amount of bass. So, the balance between the mains and center is not optimal.

Now I am getting hit with rotten eggs. Wait, various xo's incresase the dynamic range of the system and account for the different size speakers and locations in the room, right. Now this get's confusing. You would need expensive equipment to really see what the SSP is doing to measure the effects in your theater. There are some Mark Levinson systems with a xo and slope for each channel, but that is out of my price range.

So, from my understanding, setting signal xo of 80 seems to be the best to get consistent bass response from all the channels. Now, if the mains are full range it seems better to set them to Large and not use a small setting with different xo's with some low xo point. I believe high passing tower at 80 Hz is not wasting them and most likely benefit their dynamic range. Just trying to get some interesting discussion going, lol.[]

[Rich_Guy]

I just posted this in the Emotiva Forum, I'll post it here.

Crossover settings of course depend on the speakers being used. A big misconception comes from the speaker settings LARGE/ SMALL

basically

LARGE = no subwoofer is being used, no crossover is used, speakers are used full range

SMALL = subwoofer is used, crossover is used.

When using a sub the SMALL is selected and the best crossover point for blending the speaker and subwoofer is selected.

The THX recommendation is 80hz but depending on the speaker there may be a better crossover point. Generally select a point where your speaker handles good bass and just higher than the speakers bass begins to fall off.

80hz makes a good general setting but speakers that produce good bass may sound better set lower and speakers which don't have much bass may work better with a higher crossover setting.

Myself with my current speakers I use 60hz on my fronts and center and I use 70hz on my surrounds. This choice was made by knowing the specs of my speakers and experimentation and comparison listening.

When using your receiver/processors crossover settings you don't use any crossover on the sub itself. The sub settings vary usually they are OFF, LFE Mode or the subs crossover may be turned all the way up, etc, but you don't use the subs crossover as you are already using the crossover at the receiver or processor.

[Youthman]

It is my understand that you should set your xover on your sub to the highest setting (typically 120Hz) and then in your receiver, set your xover setting for your mains (ex 80Hz). This will send anything 80Hz and below info for the mains to the sub. The reason you leave your sub xover at 120Hz is because of the LFE channel. You would be missing out on any frequencies in the LFE channel from 80Hz to 120Hz (ex during explosions, gunshots etc).

[Youthman]

I just pulled up pics of the rear of my subs and realized on the RSW-15, I had it set to internal xover and a setting about 80Hz. I just switched it to "Disable LFE Mode". [:$]

And here is the back of my Velodyne HGS-15. I have the xover set to "In" and the dial turned up to 120Hz. I imagine I could switch the X-Over to "Out" and it would tell the sub not to even worry about using the Internal X-over in the sub.

[derrickdj1]

I am all for bass management. The redirected bass does go to the sub. But, if the channel xo is to low, some of the LFE is discarded. I know many systems still sound great when this is done. When I worte this post, I was just thinking about how we can maximize our systems performance. I will say one thing, it is my personal opinion that the Khorn and the Jubilee are exceptions when talking about full range speakers. Anytime a speaker can produce 124 db with only one watt is remarkable. I did not even want to touch phase issues and standing wave problems with multiple sources putting out bass.

Youthman, if you ever want to hear what I am hearing, we can swap a sub and I will try our that RSW 15, he he.

[Quiet_Hollow]

if all speakers are set to small and the xo is lower than 80, does this effect the LFE?

No.

So, from my understanding, setting signal xo of 80 seems to be the best to get consistent bass response from all the channels.

The crossover point of 80Hz is typically the best yes, but only using THX components setup according to THX placement guides does it mean you actually set the subwoofer and speaker filter points to the same value.

With non-THX gear, the actual acoustic crossover region and filter settings will rarely be the same. [8]

ie. Setting the low pass filter (or "crossover") knob on a subwoofer amp does not mean the system is necessarily crossing over at that specific frequency.

More often than not, you'll end up with the subwoofer low-passed much lower than 80 Hz and the mains high-passed just a bit higher, with the system summing correctly at ~80Hz...so long as everything is in phase there.

[derrickdj1]

More often than not, you'll end up with the subwoofer low-passed much lower than 80 Hz and the mains high-passed just a bit higher, with the system summing correctly at ~80Hz...so long as everything is in phase there

Interesting point Quiet Hollow. My understanding is that the bass from speakers set as small can be duplicated in the LFE channel. Once speakers have been xo, the signal sent to the sub has been phased shifted. Adding this shift to the LFE and there will be peaks and dip in the bass reproduce by the subwoofer. I am sure that many systems sound find reguardless of this, but is it maximizing the performance of the system?

I run my system as a THX to take advantage of the sharp slopes. IMHO, the more xo's used, the more problems for total system integration. Also, when setting up the sub and playing with the phase control, we are only getting the best sound at the xo, for the most part.

I was thinking, the avr can send bass from the other speakers to the sub, but .1 or LFE can't be sent to speakers set as small. If the speakers are xo to low, that .1 or LFE is being thrown away. This brings into question on the flat out NO answer.

[willland]

I was thinking, the avr can send bass from the other speakers to the sub, but .1 or LFE can't be sent to speakers set as small. If the speakers are xo to low, that .1 or LFE is being thrown away. This brings into question on the flat out NO answer.

I don't think so. The LFE(.1) is a completely different channel specifically recorded in movie soundtracks to be sent to your speakers/subwoofer combo regardless of individual crossover settings. If you set all your speakers at 80Hz(THX), the .1 will be sent to your speakers(above 80hz) and to your subwoofer(below 80Hz). If you were set to your mains say at 50Hz, the .1 channel info will go to mains and or the sub above 50Hz and to subwoofer only below 50Hz.

Excerpt taken from Wikipedia which I know is not the end all of factural information but the way I understand LFE:

Bass management

Surround replay systems may make use of bass management,
the fundamental principle of which is that bass content in the incoming
signal, irrespective of channel, should be directed only to
loudspeakers capable of handling it, whether the latter are the main
system loudspeakers or one or more special low-frequency speakers called
subwoofers.

There is a notation difference before and after the bass management
system. Before the bass management system there is a Low Frequency
Effects (LFE) channel. After the bass management system there is a
subwoofer signal. A common misunderstanding is the belief that the LFE
channel is the "subwoofer channel". The bass management system may
direct bass to one or more subwoofers (if present) from any
channel, not just from the LFE channel. Also, if there is no subwoofer
speaker present then the bass management system can direct the LFE
channel to one or more of the main speakers.

Low Frequency Effects (LFE) channel

Because the low-frequency effects
channel requires only a fraction of the bandwidth of the other audio
channels, it is referred to as the ".1" channel; for example "5.1" or
"7.1".^{[citation needed]}

The LFE is a source of some confusion in surround sound. The
LFE channel was originally developed to carry extremely low "sub-bass"
cinematic sound effects (with commercial subwoofers sometimes going down
to 30 Hz,
e.g., the loud rumble of thunder or explosions) on their own channel.
This allowed theaters to control the volume of these effects to suit the
particular cinema's acoustic environment and sound reproduction system.
Independent control of the sub-bass effects also reduced the problem of
intermodulation distortion in analog movie sound reproduction.

In the original movie theater implementation, the LFE was a separate
channel fed to one or more subwoofers. Home replay systems, however, may
not have a separate subwoofer, so modern home surround decoders and
systems often include a bass management system that allows bass on any
channel (main or LFE) to be fed only to the loudspeakers that can handle
low-frequency signals. The salient point here is that the LFE channel
is not the "subwoofer channel"; there may be no subwoofer and, if there
is, it may be handling a good deal more than effects.^[20]

The way I perceive LFE is that no .1 info will be lost regardless of crossover settings unless signal is lower than your subwoofer can produce.

Bill

[Quiet_Hollow]

My understanding is that the bass from speakers set as small can be duplicated in the LFE channel.

LFE is not the same as a re-routed signal from the mains. That the LFE signal combined with the remainder of the system's low-passed material can both pass through the "subwoofer out" on almost every AVR, is a source of great confusion.

Once speakers have been xo, the signal sent to the sub has been phased shifted. Adding this shift to the LFE and there will be peaks and dip in the bass reproduce by the subwoofer. I am sure that many systems sound find reguardless of this, but is it maximizing the performance of the system?

You lost me there.

I run my system as a THX to take advantage of the sharp slopes.

But none of your components are THX. It's a moot point.

IMHO, the more xo's used, the more problems for total system integration

You're confusing crossover points with filter settings. That was my point from the previous post. They are two separate terms.

Also, when setting up the sub and playing with the phase control, we are only getting the best sound at the xo, for the most part.

Yup. [Y] That's the idea.

I was thinking, the avr can send bass from the other speakers to the sub, but .1 or LFE can't be sent to speakers set as small. If the speakers are xo to low, that .1 or LFE is being thrown away. This brings into question on the flat out NO answer.

Right. I misunderstood you.

[Rich_Guy]

The way I perceive LFE is that no .1 info will be lost regardless of crossover settings unless signal is lower than your subwoofer can produce.

Bill

Correct, the .1 or LFE channel is always directed to the subwoofer. The crossover at each speaker only decides how much of that speakers channel should be directed to the subwoofer instead of that speaker (or group of speakers if there is only one crossover instead of one per speaker).

So turning the subs crossover to OFF, LFE Mode or turning it all the way up, etc. no LFE sound should be lost at least none wich the subwoofer is capable of producing.

By using a good crossover setting at each speaker no bass will be lost at that channel as any bass that speaker cannot produce or cannot produce well will be directed to the sub instead. With low frequencies that are not very directional this cannot be detected, however as frequencies get higher you begin to notice where they are coming from.

[The Dude]

On the Velodyne, if you turn the crossover to out would it all so turn off the high pass, or just the low pass. I have a Velodyne 18 dual servo, with the same setup. Why did you set your high pass to 80hz if you want the LFE signal to go to it, which wouldn't 80hz cut it off.

[derrickdj1]

The premise of this post was to find out if the redirected bass discarded .1 info. The .1 is a dedicated channel for studio engineers to put the LFE in from 3 Hz to 120 Hz. The .1 channel which as a filter(not a xo) controls the content of that channel. In my extreme example, mains xo at 40 and center xo at 100, what goes to the LPF? It seems the prevailing argument is that all the bass and LFE from the mains and center in the example is sent to the LPF. From most of the things that I have read, the information on what actually happens to the .1 signal is pretty vauge and many of the sources only refer to redirected bass and not the .1 or LFE signal.

Their is a noticeable difference running my system with the THX settings compared to not doing so. Even though the speakers are not THX certified. The avr is THX select 2 certified so it can apply the THX xo/slopes for a cleaner sound,notably in the bass quality. The main difference for the speakers are the THX requirements for directivity, on/off axis response and some other criteria. As far as speakers, I think the Klipsch are just as good for HT as Logitech which as the THX certification, lol.[]

A special thanks to all of the forum members that shared their knowledge and experience on this subject.

[The Dude]

The premise of this post was to find out if the redirected bass discarded .1 info. The .1 is a dedicated channel for studio engineers to put the LFE in from 3 Hz to 120 Hz. The .1 channel which as a filter(not a xo) controls the content of that channel. In my extreme example, mains xo at 40 and center xo at 100, what goes to the LPF? It seems the prevailing argument is that all the bass and LFE from the mains and center in the example is sent to the LPF. From most of the things that I have read, the information on what actually happens to the .1 signal is pretty vauge and many of the sources only refer to redirected bass and not the .1 or LFE signal.

Their is a noticeable difference running my system with the THX settings compared to not doing so. Even though the speakers are not THX certified. The avr is THX select 2 certified so it can apply the THX xo/slopes for a cleaner sound,notably in the bass quality. The main difference for the speakers are the THX requirements for directivity, on/off axis response and some other criteria. As far as speakers, I think the Klipsch are just as good for HT as Logitech which as the THX certification, lol.

A special thanks to all of the forum members that shared their knowledge and experience on this subject.

Thanks for sharing your findings. When you say noticeable difference, was it a good difference or bad. I would assume good, but you never know.

[Zen Traveler]

The premise of this post was to find out if the redirected bass discarded .1 info. The .1 is a dedicated channel for studio engineers to put the LFE in from 3 Hz to 120 Hz. The .1 channel which as a filter(not a xo) controls the content of that channel. In my extreme example, mains xo at 40 and center xo at 100, what goes to the LPF? It seems the prevailing argument is that all the bass and LFE from the mains and center in the example is sent to the LPF....

I'm not real sure what you are getting at but the Low Pass Filter on the sub should be set at 120...Then again, if you set your LPF lower than 120 Hz you may lose some of the LFE, but not what is directed from the other channels.

[derrickdj1]

Thanks for sharing your findings. When you say noticeable difference, was it a good difference or bad. I would assume good, but you never know.

I like the system better running it as THX. The bass is tighter, dialogue is excellent.