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Discussion Starter · #1 ·
I understand how bass management works to redirect information away from the speakers to the sub, and this question isn't about that. The question is regarding the LFE channel.


If I set my crossover to 50hz in my Pioneer 94TXH will I be throwing away the 50hz-120hz information that is LFE exclusive?


FWIW, there is no LFE crossover setting in the 94, only speaker crossover settings.


Thanks
 

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Discussion Starter · #3 ·
Thanks Simon,


Looks like from my manual (
that I did not catch that), that setting my crossover lower will indeed cut off the LFE above it.


Thanks for the link. I do have Avia, which has a LFE only sweep, as indicated in that thread, so I will try it out for myself tonight.
 

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BTW, just to nitpick, it's not really a LFE channel, but a LFE signal (hence why it only gets a decimal value of '.1' in the channel designations - e.g.: 5.1; 6.1; 7.1; etc...).
 

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Quote:
Originally Posted by PIRSQUARED /forum/post/18250306


BTW, just to nitpick, it's not really a LFE channel, but a LFE signal (hence why it only gets a decimal value of '.1' in the channel designations - e.g.: 5.1; 6.1; 7.1; etc...).

Not to nitpick, but that doesn't make any sense at all.


It is most certainly a seperate channel. LFE is encoded on DVDs and BRs as a seperate channel. If you connect a SACD, DVD-A or BRP via anlaog interconnects, the LFE channel needs it's own interconnect. LFE is encoded on DVDs and BRs as a seperate channel.
 

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Quote:
Originally Posted by Easyaspie /forum/post/18250491


Not to nitpick, but that doesn't make any sense at all.


It is most certainly a seperate channel. LFE is encoded on DVDs and BRs as a seperate channel. If you connect a SACD, DVD-A or BRP via anlaog interconnects, the LFE channel needs it's own interconnect. LFE is encoded on DVDs and BRs as a seperate channel.

Indeed, and to add to why it got the .1 instead of a full channel is because it only contains a small portion of the audio spectrum, 120hz and below and that that is not directional audio. That is the reason why it is called .1!
 

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Some receivers have an LPF setting. I have yet to understand it's usefulness.


I think most receivers lack this, and the receiver will "do the right thing" with regards to LFE.
 

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Quote:
Originally Posted by MichaelJHuman /forum/post/18250549


Some receivers have an LPF setting. I have yet to understand it's usefulness.

There has been discussion in the past and examples where the LFE channel contains content well above the bass frequencies. I don't think there is anything in the specs that limits the spectrum of the LFE channel. Therefore, it's just a good practice to low-pass filter the LFE channel.
Quote:
I think most receivers lack this, and the receiver will "do the right thing" with regards to LFE.

I don't know for sure, but I think that probably all/most receivers are low passing the LFE. A long time ago when there were only global X-over frequencies (ie same X-over applied to all channels) the entire spectrums of all the small channels were added to the LFE and then a single low-pass filter was applied.


The explicit LP filter for the LFE channel seemed to appear when separate X-overs could be applied to individual small channels where I think all the low-passed contents were added together and therefore a separate LFE filter is needed.


Ed
 

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Discussion Starter · #9 ·
So I did some testing yesterday and sure enough, Pioneer cuts off the LFE at whatever you set the speaker crossover at. I guess I will go with 80hz (which is probably the best for my speaker anyway) over the 50hz I was toying with.
 

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Quote:
Originally Posted by simon_templar_32 /forum/post/18249844

http://www.hometheaterhifi.com/volum...rs-9-2002.html

http://www.avsforum.com/avs-vb/showthread.php?t=991439


FWIW, from the 94txh manual description of crossover setting (fn2 on page 48):


"This setting decides the cutoff between bass sounds playing back from the speakers selected as LARGE, or the subwoofer, and bass sounds playing back from those selected as SMALL. It also decides where the cutoff will be for bass sounds in the LFE channel."
Quote:
Originally Posted by ******* /forum/post/18255983


So I did some testing yesterday and sure enough, Pioneer cuts off the LFE at whatever you set the speaker crossover at. I guess I will go with 80hz (which is probably the best for my speaker anyway) over the 50hz I was toying with.

That is a pretty poor design on Pioneer's part.


Mike Human alluded to a "LPF". In Denon, Onkyo/Integra AVRs (and probably others) the Low Pass Filter for the Low Frequency Effects channel (LPF for LFE) is separate and unrelated to the crossover chosen between the main speakers and the subwoofer. The speaker crossover can be set to any value supported by the AVR. The LPF can be set to any value supported by the AVR (but recommended to be 120 Hz). The speaker crossover in these AVRs does not affect the upper limit of the LFE and no LFE material is lost between the speakers crossover setting and the LPF for LFE. In other words, the sub will play back all material from the speaker crossover on down and all LFE material up to the LPF upper limit (120 Hz).
 

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Quote:
Originally Posted by ******* /forum/post/18255983


So I did some testing yesterday and sure enough, Pioneer cuts off the LFE at whatever you set the speaker crossover at. I guess I will go with 80hz (which is probably the best for my speaker anyway) over the 50hz I was toying with.

No worries, according to the hometheaterhifi article linked to above, THX found very little content between 80 & 120hz in any media.
 

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Quote:
Originally Posted by Easyaspie /forum/post/18256379


No worries, according to the hometheaterhifi article linked to above, THX found very little content between 80 & 120hz in any media.

That article is 6 years old. A lot of things have changed since then: Blu-Ray, lossless audio codecs, etc.
 

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Quote:
Originally Posted by bluesky636 /forum/post/18256445


That article is 6 years old. A lot of things have changed since then: Blu-Ray, lossless audio codecs, etc.

So do you have any verifiable proof or links that sound engineers started to put any appreciable amount of content in the LFE channel between 80 and 120hz in the last 6 years?
 

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Quote:
Originally Posted by Easyaspie /forum/post/18270703


So do you have any verifiable proof or links that sound engineers started to put any appreciable amount of content in the LFE channel between 80 and 120hz in the last 6 years?

Why should that matter in practice? With modern sources and modern equipment, an LFE crossover should be at 120Hz while the crossover for the redirected should be set according to the speakers and room acoustics.
 

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Quote:
Originally Posted by Easyaspie /forum/post/18270703


So do you have any verifiable proof or links that sound engineers started to put any appreciable amount of content in the LFE channel between 80 and 120hz in the last 6 years?

No, but I can definitely hear a difference in the LFE content in some BDs between a LPF LFE of 80 Hz vs 120 Hz. And as Kal says, if the defined upper limit to LFE is 120 Hz, why arbitrarily chop it off at 80 Hz?
 

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Quote:
Originally Posted by Kal Rubinson /forum/post/18270900


Why should that matter in practice? With modern sources and modern equipment, an LFE crossover should be at 120Hz while the crossover for the redirected should be set according to the speakers and room acoustics.

I agree.


But evidently some AVRs low pass the LFE output to whatever X-over setting you have your mains set to. So in that case any LFE content above the main X-over frequency and below 120hz is lost.


See the crux now?
 

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Quote:
Originally Posted by bluesky636 /forum/post/18271163


No, but I can definitely hear a difference in the LFE content in some BDs between a LPF LFE of 80 Hz vs 120 Hz. And as Kal says, if the defined upper limit to LFE is 120 Hz, why arbitrarily chop it off at 80 Hz?

Again, I agree. It is, IMHO, a design flaw of certain AVRs. However the point I was making is that any negative audible effects of an AVR that chops the LFE at the main X-over point, are in all likelyhood, very minimal if audible at all provided you don't set the X-ver too low. Anything 80hz and above should be fine.
 

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Quote:
Originally Posted by Easyaspie /forum/post/18277533


I agree.


But evidently some AVRs low pass the LFE output to whatever X-over setting you have your mains set to. So in that case any LFE content above the main X-over frequency and below 120hz is lost.


See the crux now?

Like I said earlier, that is a very poor design to do it that way. In the OP's case, if MCACC tells him to set the crossover at 50 Hz, LFE becomes almost useless. Unless LFE is somehow routed to the mains, which I doubt is the case. In my opinion, Denon and Onkyo do it correctly. Don't know about other manufacturers.
 

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Quote:
Originally Posted by bluesky636 /forum/post/18277584


Like I said earlier, that is a very poor design to do it that way. In the OP's case, if MCACC tells him to set the crossover at 50 Hz, LFE becomes almost useless.........Denon and Onkyo do it correctly. Don't know about other manufacturers.

Agreed.



But nobody should be setting a X-over based on a speaker's low frequency limit anyway......regardless what MCACC, Audyssey, etc, etc tells them.


Most manufacturers probably do it right. I don't think my Integra or Rotel exhibit this, but I have never really tested for it.
 

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Quote:
Originally Posted by Easyaspie /forum/post/18278101


Agreed.



But nobody should be setting a X-over based on a speaker's low frequency limit anyway......regardless what MCACC, Audyssey, etc, etc tells them.


Most manufacturers probably do it right. I don't think my Integra or Rotel exhibit this, but I have never really tested for it.

Onkyo/Integra same thing, same way. Done right.
 
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