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Discussion Starter #1
I am sure this has been discussed before,but I have used the MC 12 on a couple of installations.

Great results especially with the built in EQ.

Lexicon recommends an independent LFE subwoofer and stereo front subwoofers for best results.

I have integrated this recommedation on the first of the earlier installations,but noticed ( of course) that you lose the LFE woofer when listening to music? I would like to have all woofers woofing with music!

There has been some indication of the MC 12 "truncating" the bass fed to some of the fuller range channels depending on the crossover settings on the LFE and other speakers as well.

The current installation has 2 Infinite Baffle subs built into the crawlspace and fed into the room physically pretty close to the left and right front speakers. So I am thinking even though these are great potential LFE reproducers I am going to use them as the left and right subwoofers.

I do have 4(2 per channel) additional Boston Sub 10 f subwoofers built in the floor near the side channels,so I am going to use the Bostons as woofers for the side channels and feed the MC12 Full range side channel to a Behringer cx2310 electronic crossover. The crossover's low output will be fed to the sub10fs and the high to the smaller side channel speakers.

I am assuming with Bass management the MC12 should know what to do with the all the bass potential I have regardless of source? LFE when available will be directed to the front subs and the full range sides?

Any good reason to do this differently?

Thanks
 

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I think you're making this more complicated for yourself than it needs to be using external crossovers. It helps to keep a couple of points in mind:


- Any subwoofer connected to the "LFE" output receives ONLY discrete .1 channel content (no crossed-over bass from other speakers goes to that output). You should never use this output for anything other than dedicated LFE (as the name implies). Since the LFE channel is spec'd for 10 dB more headroom than other channels, it's helpful to put your most capable sub on this output.


- The "Sub L & R" outputs handle the crossed-over bass from the left and right sides of the room, respectively. They will also handle the LFE channel provided the LFE Sub is set to None in the speaker setup. The L&R subs do NOT have to be in the front of the room (in fact, there can be advantages to direct-to-sides placement, particularly when using the Bass Enhance feature)--what matters is that they be separated as far as possible on opposite sides to maximize the stereo bass.


- If you set any speakers as Large, then ALL crossed-over bass from the respective sides of the room will be routed to those speakers, and none of it will be sent to the L&R subs. (There was a later software mod that allows you to duplicate the crossed-over bass in the L&R subs, but this is not usually a good thing to do because you end up getting too much bass).


The bottom line is that if you set your sides to Large and use the external xovers, you might as well use the Lexicon's internal crossovers and do all the bass management cleanly in the digital domain--you'll still end up with the crossed-over bass being routed to whichever subs are connected to the Sub L & R outputs.


Hope this helps.


Cheers,

Philip Brandes
 

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Discussion Starter #3

Quote:
Originally Posted by Philip Brandes /forum/post/13012177


I think you're making this more complicated for yourself than it needs to be using external crossovers. It helps to keep a couple of points in mind:


- Any subwoofer connected to the "LFE" output receives ONLY discrete .1 channel content (no crossed-over bass from other speakers goes to that output). You should never use this output for anything other than dedicated LFE (as the name implies). Since the LFE channel is spec'd for 10 dB more headroom than other channels, it's helpful to put your most capable sub on this output.


- The "Sub L & R" outputs handle the crossed-over bass from the left and right sides of the room, respectively. They will also handle the LFE channel provided the LFE Sub is set to None in the speaker setup. The L&R subs do NOT have to be in the front of the room (in fact, there can be advantages to direct-to-sides placement, particularly when using the Bass Enhance feature)--what matters is that they be separated as far as possible on opposite sides to maximize the stereo bass.


- If you set any speakers as Large, then ALL crossed-over bass from the respective sides of the room will be routed to those speakers, and none of it will be sent to the L&R subs. (There was a later software mod that allows you to duplicate the crossed-over bass in the L&R subs, but this is not usually a good thing to do because you end up getting too much bass).


The bottom line is that if you set your sides to Large and use the external xovers, you might as well use the Lexicon's internal crossovers and do all the bass management cleanly in the digital domain--you'll still end up with the crossed-over bass being routed to whichever subs are connected to the Sub L & R outputs.


Hope this helps.


Cheers,

Philip Brandes

Thanks for the input! I am not sure what the 10db additional headroom offers me?It sounds like a bunch for movies anyway.

However I loose the really good bass these IBs can produce when listening to music.

The system changed as we were progressing. We were going to use the Boston woofers for right and left and the clients existing 12 year old Velodyne(15") for the LFE. The interior design team nixed that idea.No big boxes on the floor.

One of our techs is IB freak (Cult of the Infinitely Baffled) and suggested the crawlspace below allows for an ideal rear wave absorber. So we bought 4 15" woofers (XBL2 technology included) for a 2 woofer per manifold arrangement.

A QSC amp supplies 1200 watts per channel into the 2 ohm load for each pair of woofers.

Have not heard it as yet,but you have to be optimistic? Especially after the EQ does it's work.

So rather than use the smaller Bostons as LFE I decided to add them to the sides,but did not want to leave the smaller side speakers getting full range output from the MC12. So I added the crossover. It is actually ridiculously inexpensive! Based on your description of the bass management, I think I am going to set the bass on the side channels to a 30hz cutoff. The Bostons are probably limited below that. If I am thinking correctly than the 30 and below info from the side channels will be fed to the front left and right speakers which should get down to 20hz without too much strain?
 

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I'm not completely following this, but it sounds like you have multiple subwoofers...if that's the case and you can position at least two on opposite sides of the room, then as I said I think you're better off running those out of the MC-12 Sub L & R outs. Do not set any speakers to Large and do not use the outboard crossover--it may have been ridiculously expensive but it introduces analog domain anomalies and there's no way it will sound better than using the crossovers in the MC-12. Set the crossovers at a reasonable frequency based on what the speakers can actually handle. The MC-12's bass management is among the most sophisticated out there--why try to do an end run around it?


Cheers,

Philip Brandes
 

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Discussion Starter #5
The problem is that the side channel speakers are not really full range on their own.They are Boston Acoustic VRI 793 (3 way) in wall speakers;using 8" woofers in an hard to predict drywall enclosure. I would like to high pass those at around 50hz or 60hz. All the described woofers are (cut) built in to floor from the crawlspace,so no moving them around.

The (2) IBs are cut into the floor directly in front of the right and left side of the screen.The 4 (2 per channel) Boston sub10fs which are designed to built in the floor, are near the side walls on either side of the room. I want to add them to the system.As mentioned they are not going to produce below 30hz very easily. I thought combining them with the VRI 793s on the side channel outputs of the MC12 would work.

Again ,the problem is the MC12 does not have any "high pass" to keep below 60hz information out of the VRI 793s while allowing the Sub10fs go lower. Thats where the Behringer comes in.

I could combine(y) both the IBs and the sub10fs on the left and right sub outs? Again I would be forcing the Sub10fs to go lower than they are capable? I am attaching a picture of the room as it is being finished,the sub10f woofer as well as a picture of the IB from the crawlspace.

This is fun anyway you arrange it?


 

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Quote:
Originally Posted by ddingle /forum/post/13011733


I am sure this has been discussed before,but I have used the MC 12 on a couple of installations.

Great results especially with the built in EQ.

Lexicon recommends an independent LFE subwoofer and stereo front subwoofers for best results.

I have integrated this recommedation on the first of the earlier installations,but noticed ( of course) that you lose the LFE woofer when listening to music? I would like to have all woofers woofing with music!

There has been some indication of the MC 12 "truncating" the bass fed to some of the fuller range channels depending on the crossover settings on the LFE and other speakers as well.

The current installation has 2 Infinite Baffle subs built into the crawlspace and fed into the room physically pretty close to the left and right front speakers. So I am thinking even though these are great potential LFE reproducers I am going to use them as the left and right subwoofers.

I do have 4(2 per channel) additional Boston Sub 10 f subwoofers built in the floor near the side channels,so I am going to use the Bostons as woofers for the side channels and feed the MC12 Full range side channel to a Behringer cx2310 electronic crossover. The crossover's low output will be fed to the sub10fs and the high to the smaller side channel speakers.

I am assuming with Bass management the MC12 should know what to do with the all the bass potential I have regardless of source? LFE when available will be directed to the front subs and the full range sides?

Any good reason to do this differently?

Thanks

I have the Lexicon MC12-HD and am using 2 Gotham subs both wired for both HT as well as 2 channel listening. My main preamp for audio however is the Audio Research Ref 3. IMO the Lexicon is great for most things but not for music.

You can have a look at my photos and a description of how I solved the problem here

http://forum.audiogon.com/cgi-bin/fr...927&read&3&4&5


Essentially I do not bring any LFE or sub signal out of the Lexicon. Rather I bring Left and Right Main out of the Lexicon into the Processor input (aka theater throughpass) of my Ref 3. I then bring a pair of main outputs into my Lamm ML 2.1 amps and then to my Wilson X-2 speakers. I bring a second set of main output cables into my Gotham subs. Essentially I am running two loads in parallel and to prevent overworking my Ref3 the main outs to the Gothams are patched through a Musical Fidelity Tube Buffer which has an input impedance of 470 KOhms.More description of what I did can be read here

http://forum.audiogon.com/cgi-bin/fr...flup&584&4#584



Therefore for HT I use the Lexicon as the preamp and for audio I use my Ref3.


Lexicon calls this "Full + SubS"
 

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You should be able to go into the custom settings and set your X-over's for subs and LFE. Also you can turn the LFE on or off depending on each device you have. It is time consuming to set-up this way for Satellite and or Cable,DVD,CD,Tape,etc...but I hope you understand that this the best way for each device you have in regard to analog and or digital inputs.
 

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I do not see you gain much but complexity and issues in crossover at 50-60 hz to subs that are only capable to maybe 30 hz. Part of the rationale for a separate LFE was to allow more headroom for the sub by not taxing it with the derived bass of the other speakers. I would suggest canning the Boston sub10fs for this project. Use the Lexicon crossovers for the bass management and use the IB's as left and right subs with no separate LFE sub. They should be highly capable of handling both the derived bass and LFE duties.


Regards,

Will
 

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Discussion Starter #9

Quote:
Originally Posted by Will Gibbons /forum/post/13015188


I do not see you gain much but complexity and issues in crossover at 50-60 hz to subs that are only capable to maybe 30 hz. Part of the rationale for a separate LFE was to allow more headroom for the sub by not taxing it with the derived bass of the other speakers. I would suggest canning the Boston sub10fs for this project. Use the Lexicon crossovers for the bass management and use the IB's as left and right subs with no separate LFE sub. They should be highly capable of handling both the derived bass and LFE duties.


Regards,

Will

The sub10fs are pretty capable deep bass producers,but not like the much larger woofers used for the IB.

The bass management magic from the MC-12 seems key to success here? I am pretty sure adding (down to 30hz) bass from the sub10fs positioned at different points in the room is going to help the overall room bass response compared to the IBs alone. Especially from different seating positions? So since I have them already cut into the floor, I might as well add them to the mix.

I do not recall the MC12 having an option for different speaker arrangements(LFE on or off) per input? Certainly the EQ counts on the speakers staying the same for it's desired effect?
 

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Adding additional subwoofers in fixed locations does not insure more even bass response in the listening area. Most of us have limitations on which location(s) we can locate our subs, but some flexibility is the norm. With prepositioned and fixed speaker & sub locations, the listening area itself may have to be a bit more flexible, especially if the planned seating occupies a null. You can pre-model the room for anticipated response, but testing and measuring with furnishings in place will be necessary. Judicious use of acoustic treatments would probably be advised. The better the room, the better the total results with EQ would be.


Good luck,

Will
 

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"I do not recall the MC12 having an option for different speaker arrangements(LFE on or off) per input? Certainly the EQ counts on the speakers staying the same for it's desired effect?"


For cross over set up there is THX set-up and Custom set-up, on custom set-up you can turn your LFE on and off.


Why would you not be able to do a custom set-up per input..? this is something that Lexicon has provided in the past even before the MC-1.


I run an Infinite baffle for my main LFE now and 2 SV-subwoofers for my left and right and can run exactly what you are trying to achieve. Be it Dolby,DTS,Logic-7 or 2-channel everything can be designed to your preference.
 

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Discussion Starter #12

Quote:
Originally Posted by ybsane /forum/post/13017197


"I do not recall the MC12 having an option for different speaker arrangements(LFE on or off) per input? Certainly the EQ counts on the speakers staying the same for it's desired effect?"


For cross over set up there is THX set-up and Custom set-up, on custom set-up you can turn your LFE on and off.


Why would you not be able to do a custom set-up per input..? this is something that Lexicon has provided in the past even before the MC-1.


I run an Infinite baffle for my main LFE now and 2 SV-subwoofers for my left and right and can run exactly what you are trying to achieve. Be it Dolby,DTS,Logic-7 or 2-channel everything can be designed to your preference.

Thanks for the input!

I have always used the same "Custom" speakers settings for all inputs? I am assuming the EQ would only work effectively on the "custom" setting it was adjusted in? So in order to take advantage of the EQ, I have to leave the custom settings the same for each input?

In addition in order to access all the woofers for cd playback(for example),none of the woofers can be connected to the LFE output of the MC12? If I turn off the LFE, anything connected to it is not functional. Or as usual am I missing something
 

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Discussion Starter #13

Quote:
Originally Posted by Will Gibbons /forum/post/13016718


Adding additional subwoofers in fixed locations does not insure more even bass response in the listening area. Most of us have limitations on which location(s) we can locate our subs, but some flexibility is the norm. With prepositioned and fixed speaker & sub locations, the listening area itself may have to be a bit more flexible, especially if the planned seating occupies a null. You can pre-model the room for anticipated response, but testing and measuring with furnishings in place will be necessary. Judicious use of acoustic treatments would probably be advised. The better the room, the better the total results with EQ would be.


Good luck,

Will

Appreciate the input!

No acoustic treatment happening in this multipurpose room. It is however a really big room. Ceilings are 15 to 20 feet. Non parallel ceiling as well. Hopefully the seating area doesn't end up in a null,but this big space hopefully will not have the typical small room humps.
 

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Ok, just got home and checked to see what mine actually does, DolbyDigital and DTS are the only sources that engage the LFE , other wise its just the stereo subs engaged. Keep in mind that with the SVS for stereo it sounds very good and until I got up close to the infinite baffle I could not tell they if where working or not because the bass from the SV-subs moved the driver a little.


But back to your question, the LFE only works that way with a Dolby or DTS 5.1 track.This what It could see by toggleing back and forth in the menu to see if it was on or not. Even if you check on for LFE, the system turns it off for non 5.1 sources.


I just found it on 5-46 in the manual..
 

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Dallas,


If you want "all woofers woofing" all the time, then don't use the dedicated LFE output. As the name implies, it is active only[/i] when there is a .1/LFE channel in the source material. So configure the LFE output to None and just don't use it. Simple as that. No need to make this unnecessarily complicated. You still have 2 subwoofer outputs that you can take advantage of, configured as stereo or dual-mono (may be a better choice when running those 2 outputs to more than 2 subs).


Sanjay
 

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Discussion Starter #16

Quote:
Originally Posted by sdurani /forum/post/13019248


Dallas,


If you want "all woofers woofing" all the time, then don't use the dedicated LFE output. As the name implies, it is active only[/i] when there is a .1/LFE channel in the source material. So configure the LFE output to None and just don't use it. Simple as that. No need to make this unnecessarily complicated. You still have 2 subwoofer outputs that you can take advantage of, configured as stereo or dual-mono (may be a better choice when running those 2 outputs to more than 2 subs).


Sanjay



Hi Sanjay! Thanks. So you are saying use the 4 Boston sub10fs and the Two IB woofer cabinets all together as dual mono output from the front left and right sub output of the MC12? Using y connectors of some sort?

Since the sub10fs would be "stretched" to be equalized to reproduce a 20 hz output, while the IBs would be handling the EQ with relative ease, would it make any sense (as discussed) to use the sub10fs as side channel woofers with a cutoff of 30hz?

Wouldn't the lower than 30 from the sides than be fed to the front left and right subs?

Kind of maximizing the use of bass management to get the most of all the woofers in the system?
 

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Dallas,


Yes, I was recommending using Y-connectors to send the 2 sub outputs to 4 subwoofers. You could use the external Behringer crossover to send content below 30Hz from the Bostons to the IBs, but that's adding more complication and additional A-to-D and D-to-A steps (I think the Behringer works in the digital domain).


With the dual-mono setting, you can Y one sub output to the Bostons and Y the other sub output to the IBs. While they'll be outputting the same signal, each sub output can be calibrated independently for level and time alignment as well as room EQ. So if the two bostons are placed symmetrically from the sweet spot (calibration location), then it's fine if they have the same delay. For levels and EQ, the system will see both Bostons as one subwoofer. Ditto the IBs: they will be seen as one subwoofer for the purposes of time alignment, levels and EQ.


I know this isn't optimal, but it is a way to get all woofers woofing all the time without setting up some sort of Rube-Goldberg contraption for low frequency routing. Keep in mind this wouldn't be necessary if you were using only 2 subs or willing to have a dedicated LFE sub that went silent when there was no .1/LFE channel in the source material. Not trying to discourage you, just pointing out that you'll have to live with some compromise to have all four subs active all the time.


Sanjay
 
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