Crossover and Speaker Settings in Relation to Bass Management

Status
The first post in this thread is a WikiPost, and can be edited by anyone with the appropriate permissions.
Old movies tend to have 2 channel audio or even mono soundtracks. THere's not be an LFE channel anyway in association with such films.

If desperate, you could theoretically decode the source onboard the player and convey multichannel PCM to the AV receiver. Again, I'm not sure as to whether the AVR would then downmix any inclusive LFE channel though?


You have to recognise that the LFE channel was never intended to be portrayed by conventional passiv speakers so the is no real incentive to provide provision to portray that channel in the absence of an active sub. You are lucky that they do mix it down into the front stereo channels on systems devoid of a passive sub. I'm not at all sure you'd be missing anything if mixing down multichannel soundtracks and hving to sacrifice the LFE channel though?

Again, if desperate then turn off all the speakers (sst to none) other than the stereo pair. This may in fact result in the LFE channel being mixed down into the stereo left and right channels?
 
Last edited:
Tried lexicon.set to 120hz for a movie, just too boomy.

Soundstage on 80hz and bass just cleaner not droaning all the time.

Interestly looking through marantz av7705 manual.it has LPF and subwoofer crossover setting.

So wonder if the setting in mc-8 is one of those, it doesn't state lpf, so perhaps it's one of those possky sub crossover and maybe log is hidden but still always set at 120hz?
 
Sorry, but what have you set to 120Hz on the Lexicon? The crossovers would be at 80Hz and not 120Hz. You have no control over the LFE channel.


I'd only be repeating what I've already postd if I tried explaining this to you.


Do not use an LPF of LFE filter to limit what is being output to your sub. This filter only applies to the LFE channel and is not a crossover. It should be left set to 120Hz regardless.

Audyssey Labs:
The LPF filter for the LFE channel should always be set to 120 Hz. Any other setting is wrong. This filter has nothing to do with speaker roll offs and crossovers. It is a filter that is applied only to the separate LFE track found in 5.1 content. That material is authored to have content up to 120 Hz.

The crossover filter are a separate matter. They consist of a highpass and lowpass filter that is applied to the signal sent to each speaker. They are determined after the in-room measurements find the roll off points of each speaker.

 
Last edited:
Screenshot_20200411-110706.png
 
Maybe the Lexi does not have a lpf .1 channel management setting, how old is it? .1 movie content shouldn't being played anyway in stereo mode although the sub can still be used, in which case it should crossover at what you have your main L/R speakers at I.e 60hz. Maybe, there lies the problem, the Lexi crosses over on what you have the sub crossover set at and needs to be manually changed if being used in stereo for music? Or perhaps it has a mode that bypasses sub crossover setting for stereo and crosses over where you have mains crossover set?
 
With Marantz, lpf is set at 120hz only for that .1 lpf channel content, otherwise speakers and subs crossover at what has been assigned for speaker crossovers
 
It does however appear by your manual picture that I would set the sub to crossover at your lowest crossover for the speakers, since no LFE LPF management and without that id hazard 120hz would be too high for music?
 
Does setting all speakers to 80hz and sub at 80hz sound any better (or 60hz -100hz)?
 
Yes. Tried 80hz for everything, sounds a lot better than having sub at 120hz.

Course speakers sound bad at 120hz like.littlr.bookshelf speakers
 
If a receiver has no dedicated LPF of LFE setting then that device has no means by which to filter the LFE channel. It is common to not have such a filter and many AV receiver lack such a filter. THe LPF of LFE as ansolutely nothing at a;; yp do with crossover filters and is only applicable to the LFE channel when and if present. Likewise. the crossover filters have no effect upon the LFE channel and are only applicable to the frequencies at and below their settings relative to the speakers designated as SMALL that they are associated with.

On the Lexicon, use either the THX option or the 30 to 120Hz option. The THX option equates to setting all the speakers as being SMALL with a crossover of 80Hz while the second option allows you to define exact;y what the crossovers for the speakers designated as being SMALL should be.

The LFE channel is a discrete channel whose ceiling is 120Hx, hence why you should not filter it and discard any of its conent below 120Hz. The LFE channel is not subject to the crossover filters and even if there is an LPF of LFE option then this should always be left at 120Hz.
 
Last edited:
Does setting all speakers to 80hz and sub at 80hz sound any better (or 60hz -100hz)?


Doing so is incorrect. The only filters that should be in used are those onboard the AV receiver. You are discarding aspects of the LFE channel if you set the sub's own filter below 120Hz. THe crossovers onboard the AV receiver determine at which point to redirect frequencies away from the passive speakers designated as being SMALL to the sub for the sub to handle. THe LFE channel is set to the sub automatically and is not influenced by the crossovers.


There's no legimate reason to filter the LFE channel or reduce its scope. Its ceiling is 120Hz.


Even onboard receivers that have an LPF of LFE option, this is left set to 120Hz.


Anyone suggesting that this results in adverse effects is talking bullshit. I say this because the LFE channel isn't continually using its full 120Hz range and the 80 to 120Hz aspect of it is basically headroom included to allow for a very gradual roll off. Most of the LFE channels cntent will be in the frequencies below 80Hz.
 
Last edited:
I've already told you subwoofer own is setting on the back panel is disabled. Svs SB Ultra 13.

Setting 120hz for the sub on the lexicon as seen in that screenshot sounds bad. It sounds best following instructions, for example mains 60hz, all other bookshelf to 80hz, sub 60hz. Or all 7.0 to 80hz, sub to 80hz. I could tell the subwoofer was on when set to 120hz, and those frequencies stood out from the soundstage. Watched "Fury"

Interesting once I get a new AV pre which have specific LPF, ie marantz 7705 default is 120hz. If it sounds boomy then the same problem, a flawed bass management system. And I'll change LPF to 80hz
 
otherwise speakers and subs crossover at what has been assigned for speaker crossovers


No, the sub's filter should not be set to whatever you've set you crossovers to! The sub's own filter is surplus to requirements and should either be set to a setting that bypasses it such as an LFE mode for example or it should be set to its maximum possible setting to avoid it interferring with the already filtered output from an AV receiver. THe AV receiver should be the only device filtering the output to the sub and the AV receiver is the device dealing with the bass management.
 
Last edited:
I've already told you subwoofer own is setting on the back panel is disabled. Svs SB Ultra 13.

Setting 120hz for the sub on the lexicon as seen in that screenshot sounds bad. It sounds best following instructions, for example mains 60hz, all other bookshelf to 80hz, sub 60hz. Or all 7.0 to 80hz, sub to 80hz. I could tell the subwoofer was on when set to 120hz, and those frequencies stood out from the soundstage. Watched "Fury"

Interesting once I get a new AV pre which have specific LPF, ie marantz 7705 default is 120hz. If it sounds boomy then the same problem, a flawed bass management system. And I'll change LPF to 80hz


Yeah, but you keep ignoring everything else I keep trying to convey to you and you keep onsisting that you need to try filter the output from the receiver so that you discard aspects of the LFE channel.

Leave it alone!

If you are having issues with the bass then it has sod all to do with the LFE's 120Hz ceiling. I'd suggest you investigate the room's acoustics.


The 80 to 120Hz aspect of the LFE channel is simply a roll off and isn't causing bass boom in anyone's setup.
 
Last edited:
Dante, I'm talking specifically on his setup and the picture he posted regarding the subs crossover, all of my posts are in regard to this setting in the lexi not the subs own settings.
 
No, the sub's filter should not be set to whatever you've set you crossovers to! The sub's own filter is surplus to requirements and should either be set to a setting that bypasses it such as an LFE mode for example or it should be set to its maximum possible setting to avoid it interferring with the already filtered output from an AV receiver. THe AV receiver should be the only device filtering the output to the sub and the AV receiver is the device dealing with the bass management.

I know that but his Lexi has a specific sub setting xover which appears NOT to be the descrete LFE channel I.e like on a Marantz bass management. He has also stated the subs own management is defeated.
 
Yes. Tried 80hz for everything, sounds a lot better than having sub at 120hz.

Course speakers sound bad at 120hz like.littlr.bookshelf speakers

I posted a link toba spreadsheet earlier in this thread which might help you check the nulls out in your room and possible remedies regarding positioning. There is also REW room sim but to be fair I found the spreadsheet better
 
Question is this, why is the lpf of lfe (if it is?) affecting stereo music, it shouldn't. The speakers should crossover where it's set to I.e on my Marantz for sake of simplicity 80hz, whilst the dedicated lfe channel is set and left at 120hz and DOES NOT affect stereo music. Of course subs own bass management is OFF. Hence I asked if the Lexi does bass management or high freq cutoff differently. Is it sending 120hz to the sub FOR ALL and not just the descrete .1 channel?

what affect does FULL have if set for the sub IN the Lexi?
 
Last edited:
The exact point I've been attempting to make. Besides this, the LFE channel isn't continually consisting of frequencies in the range 80 to 120Hz. The mix uses that extra range to facilitate an LFE channel roll off in order to avoid abrupt cutoffs ar 80Hz. Even if not using an LPF of LFE to lower the LFE cutoff below 120Hz, you'd still not experience bass boom relative to the 80 to 120Hz aspect of the LFE channel because most mixes are not utilising that additional range in the manner you appear to think it is being used.
 
If a receiver has no dedicated LPF of LFE setting then that device has no means by which to filter the LFE channel. It is common to not have such a filter and many AV receiver lack such a filter. THe LPF of LFE as ansolutely nothing at a;; yp do with crossover filters and is only applicable to the LFE channel when and if present. Likewise. the crossover filters have no effect upon the LFE channel and are only applicable to the frequencies at and below their settings relative to the speakers designated as SMALL that they are associated with.

On the Lexicon, use either the THX option or the 30 to 120Hz option. The THX option equates to setting all the speakers as being SMALL with a crossover of 80Hz while the second option allows you to define exact;y what the crossovers for the speakers designated as being SMALL should be.

The LFE channel is a discrete channel whose ceiling is 120Hx, hence why you should not filter it and discard any of its conent below 120Hz. The LFE channel is not subject to the crossover filters and even if there is an LPF of LFE option then this should always be left at 120Hz.
exactly and I think that his Lexi does not have a lfe channel management so therefore do you recommend that he still sets the sub xover IN HIS amp to 120hz for stereo music or set it at 80hz if all of his other small speakers are set for simplicity to 80hz? Id guess 80hz since he stated its less boomy. I am not disagreeing with you but pointing out his amp may not have a lfe channel setting.
 
Last edited:
As to configuring the Lexicon and the specifics of that device, maybe ask in a thread that deals with that device or open a new topic in the relavant section of the board?

Other than this, you shouldn't be using an LPF of LFE to limit the LFE channel to frequencies below 120Hz.
 
exactly and I think that his Lexi does not have a lfe channel management so therefore do you recommend that he still sets the sub xover IN HIS amp to 120hz for stereo music or set it at 80hz if all of his other small speakers are set for simplicity to 80hz? Id guess 80hz. I am not disagreeing with you but pointing out his amp may not have a lfe channel setting.


If the Lexicon is devoid of an LPF of LFE feature then the only way of limiting the LFE channel's range would be via the sub's own onboard filter. This would also not be advisable though and isn't the recommended way to setup a system.


Most AV receivers lack an LPF of LFE and it shouldn't be an issue because you shouldn't theoretically be using such a filter to limit the LFE channel or decrease it to frequencies below 120Hz. It is recommended to set the LPF of LFE to 120Hz even if a device has such a filter.
 
Last edited:
@rccarguy, it sounds like you're describing cascading crossovers: Guide to Subwoofer Calibration and Bass Preferences - AVS Forum | Home Theater Discussions And Reviews

This is something I've been playing with myself (although my processor doesn't allow the setting of an LPF on the LFE) with fair success.

The point is that, while @dante01 is correct, using an LPF lower than the maximum of the LFE channel does cause LFE channel information to be lost, the amount of content in the LFE channel between 80Hz and 120Hz isn't much, is often replicated in the LCR, can losing it can actually improve things. A lot of "ifs" and subjectives in there, I know.

Setting the LPF on the sub would only really have any advantage with n.0 channel if the filter types or slopes in the receiver and the sub are different or the crossover in the receiver isn't working correctly. Otherwise you're just replicating the same filter.
 
I’d like a sanity check on my new setup as I changed my LCR speakers and reran Audyssey. It sounds awesome but looks a little strange in the config!

Audyssey tries to set the LCR to large and 40hz (I manually set them to small and 80hz). It sets the Sub distance to over 3.4m when it’s actually no more than 2.4m. It sets weird numbers for the surrounds, back and atmos speakers (Which I increase to 120hz, 200hz respectively).

Audyssey Setup:
65182278-9A86-4724-81ED-1621F3ACD618.jpeg37A7880A-2CF2-4273-9B38-BD88C7C373B1.jpeg2B9D2A02-8E44-4B49-83EA-6249D5631F91.jpegEC94056A-7151-4244-95FC-9ED148ED1BC0.jpeg

Manually tweaked afterwards:
56842DEC-7562-4E08-8F13-A7CF99E45D69.jpeg19FEEFDB-41BA-42E5-BD62-5A139AEBF4B5.jpeg98FD44EF-736D-438F-9740-A20F972FEBF4.jpegE0B840D8-307F-474B-A642-CFCD31C5C6F7.jpeg4F092489-1A27-4E5D-BCB7-378D4EBFF269.jpeg357363F4-78A1-432F-B4F1-425A19CF4248.jpeg

Speakers: M&K 750 THX LCR, Surrounds M&K K4 Tripoles, Surround Backs Kef Eggs 2005, Atmos x 4 Cambridge Audio Minx, Sub XTZ 1x12, Amp Denon X6400H.

Other details: Physical controls on Sub are manually set to max 160hz crossover, LFE bypass On, volume knob set to min (see below).

On Amp all Denon limiters like Dynamic volume are off. Weirdly the Denon sub volume configuration only gets to 76db if I turn the XTZ volume knob right the way down to minimum! Anything else and the Denon sees it as to loud.

Now it does sound bloody amazing 😉 but it looks odd so thoughts?
 
Status
The first post in this thread is a WikiPost, and can be edited by anyone with the appropriate permissions.

The latest video from AVForums

Is 4K Blu-ray Worth It?
Subscribe to our YouTube channel
Back
Top Bottom