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Discussion Starter · #1 ·
I have upgraded to a Lexicon MC-12B which sounds great but I have lost bass output. I run a pair of 29-39CS+ subs driven by a Hafler XL-600 that provides 500watts/channel. Subs are next to each other rear corner loaded.


The MC-12 left sub output is connected to an RCA that is split to both Hafler channels. On the Lex sub=mono xover=70HZ LFE=on

All speakers have 80HZ crossover and lower response limits.


Previously using Audio Control Richter Scale xover40Hz Freq Response=1

No EQ. just via Lex=2

One sub=3

All values corrected.

MC-12 internal calibration tones to 75dB. What freq. is the sub cal tone?


Hz 1 2 3

17 81.5

20 79.5 73.5 70.5

25 83.5 76 76

31 92 86 77

40 94 88.5 77.5

50 71.5 75.5 69.5

60 74.5 69.5 55.5

70 69.5 60.5 59.5

80 74 72 71


What has happened to my 20Hz and below response? Do I have the Lex hooked up correctly? Where do I go from here?


Thanks,

Dave
 

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Dave,


"the Lex sub=mono xover=70HZ LFE=on "


Having LFE= ON means LFE channel bass is routed to the LFE output.... which you aren't using. Turn LFE = OFF and it re-routes LFE out the sub output.


Shawn
 

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Shawn's right. In your present configuration, you are sending your LFE info into the void.


Another observation: Y-splitting a mono sub output is only one of your bass management options. You might want to at least try the MC-12's stereo sub capability, with the subs on opposite sides of the room. This will also allow you to experiment with the Bass Enhance function. You have a lot of options--experimenting is part of the fun!


Cheers,

Philip Brandes
 

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I think the MC-12 uses the standard 40-80hz 1 octave band *noise* for the subwoofer calibration.


TV
 

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Discussion Starter · #6 ·
Thanks for the help;my bass is back :).


My room response has a few big humps at 40 and 50 HZ but the system sounds much better than it measures using the Granite Audio test CD. I was told by Don at Granite that this CD is best used for resonance testing purposes not freq. response. I didn't ask him how far off my results would be using a single tone per freq. Will a flat freq. response mean a really big improvement in sound or am I just torturing myself?


I have not have time to experiment with splitting the subs or bass enhance. I am concerned with additional cancellation/rom node issues with stereo subs. In a 10'9" x 24x 8" room will the 20-39CS+ subs approach reference levels if split?


This weekend I will probably be able to get a buddy to help me try different sub positions/combos/response measurement.


Dave


BTW, I think that this would be a great place for a new Lexicon gathering because it is much easier than the SMR forums to navigate.
 

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Dave,


When measuring also be sure you have Loudness OFF. That is a volume dependant EQ boost that is applied to the signal to compensate for how we hear. While it usually sounds very good (on a calibrated system) it would throw off your measurements.


Shawn
 

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I would gladly join a Lexicon gathering, as I worship my MC 12. I am such a fan that I had a mouse pad made with a picture of an MC 12 on it so that I could have it with me at work. I get lonely if I don't have an MC 12 or at least a picture of one in the room.

I even went so far as to buy a giant Lexicon sign from an Audio store which closed and put it in my living room.

I wear Lexicon T-shirts, which I had custom made.

____

Does the words: This man needs to get a life ring a bell.


I am a sadly addicted man.
 

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Dave,

"I have not have time to experiment with splitting the subs or bass enhance. I am concerned with additional cancellation/rom node issues with stereo subs."


You will get cancellation due to interference if your two subs are reproducing correlated signals, and they are separated by a significant distance, ie. you feed both of them the same signals, and place them in different parts of the room. Bass enhance decorrelates bass, and shouldn't cause the same kinds of interference. If you're going to go through the trouble of measuring your bass response, you may as well take the time to experiment with bass enhance.


--Andre
 

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Quote:
I even went so far as to buy a giant Lexicon sign from an Audio store which closed and put it in my living room.


I wear Lexicon T-shirts, which I had custom made.
Yeah, okay, but do you think it sounds good (in addition to just looking at the picture) :)


You're an even more ardent fan than I thought I possible :)
 

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Yes, I think it sounds fantastic. I love all the tweaking you can do with it. I guess this comes from my software engineering background. I really appreciate a good software program. And Version 1.1 is very well done.
 

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Discussion Starter · #12 ·
Andre,

That makes a lot of sense. This weekend I will experiment.


Farscape,

Nothing succeeds like excess.


I set my unit up after 3 hours of sleep and a cursory read of the manual. Since then I have been really pleased with the sound. I did find that with the movie Sniper that DPLII did a better job than Lex7. The dialogue in a scene was "smeared" across the front soundstage while DPLII did not make this error.


I do have another confession to make. Last night after re-watching Crimson Tide I was really impressed with the MC-12's sound. I heard things that were never their before. After the movie I re-read the bass management section of the manual and accidentally discovered that I had been using the wrong mode. I was using Lex 7 instead of the 5.1 Lex 7! What a bonehead move. It was late and I only had 5 minutes to listen with the correct mode but needless to say this unit will only get better if I set it up properly.


This is gonna be good....


Dave
 

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Have you tried experimenring with the 5/7 Speaker switch? Or the 5 speaker enhance setting on the L7 modes?
 

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Discussion Starter · #14 ·
The 5 speaker enhance is ON but where is the 5/7 speaker switch? I only have 5 speakers configured. My dealer informed me that I shouldn't use rear for a 5.1 system. Even though my surround speakers are behind me I switched them to sides as he suggested. The rears are set as none.


Just finished watching Swordfish again. Great sound. My front speakers have dissapeared and the soundstage extends past my room's walls. This is a different league than my B&K or the Proceed AVP that I demoed.
 

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Dave,


"The 5 speaker enhance is ON but where is the 5/7 speaker switch? "


Right on the remote but since you only have 5 speakers it doesn't matter.


"My front speakers have dissapeared and the soundstage extends past my room's walls."


Try it with the full seven speakers sometime!


Shawn
 

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A few things which have been brought up:


The 5/7 switch is one of the small buttons on the remote around the arrow keys. It only works if you have 7 speakers and you want to find out what going back to 5 speakers sounds like.


When using a 5 channel setup, ideally the surround speakers would be to your sides instead of behind you. I think this is what your dealer meant. If your speakers are more behind you than to the side, you might want to set them up as rears instead of sides.


The consensus on 5 speaker enhance is to leave it on at all times independent of the number of speakers in use. This has something to do with Logic 7 processing.


The "plain" Logic 7 modes (film, music & TV) only work with 2 channel sources while the 5.1 Logic 7 modes are for multichannel sources. The MC-12 should automatically select whatever 2 channel (Logic 7) or multichannel (5.1 Logic 7) mode you have defined as default for that input. You should use a digital connection (single optical or 75-ohm coax cable) between your DVD player and the MC-12 for movies. Normally if a multichannel Dolby Digital signal is present (most movies) you will not be able to select one of the "plain" Logic 7 modes, only the 5.1 modes. I am not sure why you were able to switch during the movie. I don't think everything is configured properly for that input.
 

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Quote:
Originally posted by quattro98
When using a 5 channel setup, ideally the surround speakers would be to your sides instead of behind you. I think this is what your dealer meant. If your speakers are more behind you than to the side, you might want to set them up as rears instead of sides.
This isn't necessarily ideal, as it leaves a huge hole in the rear soundfield. In 5.1 speaker setups, a very popular placement is to put the surrounds at 110 degrees instead of directly to the sides (even when using dipoles). This helps fill in the gap behind (though not completely), but somewhat at the expense of stable side imaging (which benefits from direct-to-side placement). The point being that there is no way to get a continuously immersive soundfield with only 5 speakers--there will always be holes somewhere. Which is why Lexicon has always implemented sides and rears for surround use.


Quote:
I think this is what your dealer meant. If your speakers are more behind you than to the side, you might want to set them up as rears instead of sides.
Actually, I think his dealer was still following the guidelines for the original DC-1 software, which required you to use the sides, rather than the rears, when using only one pair of surrounds. However, that requirement was changed quite some time ago, and the current software in all the Lexicon processors will automatically compensate regardless of which physical connection you're using. So it really doesn't matter which you use, as long as you configure the unused speakers to NONE.

Quote:


The consensus on 5 speaker enhance is to leave it on at all times independent of the number of speakers in use. This has something to do with Logic 7 processing.
Exactly right--this is why this parameter defaults to ON even when using 7 speakers, and ON it should stay.

Quote:
The "plain" Logic 7 modes (film, music & TV) only work with 2 channel sources while the 5.1 Logic 7 modes are for multichannel sources. The MC-12 should automatically select whatever 2 channel (Logic 7) or multichannel (5.1 Logic 7) mode you have defined as default for that input. You should use a digital connection (single optical or 75-ohm coax cable) between your DVD player and the MC-12 for movies. Normally if a multichannel Dolby Digital signal is present (most movies) you will not be able to select one of the "plain" Logic 7 modes, only the 5.1 modes. I am not sure why you were able to switch during the movie. I don't think everything is configured properly for that input.
I don't think he said he was able to switch, only that he realized he was listening to the 2.0 L7 mode. This was probably because he failed to select the 5.1 Dolby Digital track on the DVD menu (some discs default to the 2.0 Dolby Surround mix). But you're right, there is no way to toggle the MC-12 between 2.0 and 5.1 Logic 7, as the MC-12 will autodetect the format and load the appropriate effect for that source.


Quote:
Originally posted by DaveN
I did find that with the movie Sniper that DPLII did a better job than Lex7. The dialogue in a scene was "smeared" across the front soundstage while DPLII did not make this error.to switch during the movie. I don't think everything is configured properly for that input.
It wouldn't be a problem with the Input Configuration. Smearing across the L-C-R is a symptom of a time alignment problem; most likely you need to fine tune the center speaker distance. A handy way to optimize this is to use the L7 Music mode while listening to a mono source (this will spread center-steered content across the L-C-R). While in this modes, try varying the center speaker distance setting a little bit above and below its current setting; when you get it right, you should hear the center image snap into focus, indicating your center is properly time-aligned with your left and right fronts.


Cheers,

Philip Brandes
 

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Well I must admit I never knew that the 5 Speaker Enhance mode should allways be left on. The manual was not entirely clear on this point at all. I assumed it was only needed if you only had 5 speakers, but since I had 7 I rarely used it. So now I have to turn it on and watch some of my favorities again and see the difference.

___

Thats what I love about this device, so many options!!!!

____

Too bad there is not a "recommended setting FAQ" somewhere for the MC-12. It deserves one.
 

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Discussion Starter · #19 ·

Originally posted by Philip Brandes



This isn't necessarily ideal, as it leaves a huge hole in the rear soundfield. In 5.1 speaker setups, a very popular placement is to put the surrounds at 110 degrees instead of directly to the sides (even when using dipoles). This helps fill in the gap behind (though not completely), but somewhat at the expense of stable side imaging (which benefits from direct-to-side placement). The point being that there is no way to get a continuously immersive soundfield with only 5 speakers--there will always be holes somewhere. Which is why Lexicon has always implemented sides and rears for surround use.


Sometimes we have to live with the cards that we have been dealt. My room cannot physically support side speakers. My "rears" are 7.5 feet behind me and placed about 8 feet apart. I will measure later.




Actually, I think his dealer was still following the guidelines for the original DC-1 software, which required you to use the sides, rather than the rears, when using only one pair of surrounds. However, that requirement was changed quite some time ago, and the current software in all the Lexicon processors will automatically compensate regardless of which physical connection you're using. So it really doesn't matter which you use, as long as you configure the unused speakers to NONE.


That is how I initially had it configured.



I don't think he said he was able to switch, only that he realized he was listening to the 2.0 L7 mode. This was probably because he failed to select the 5.1 Dolby Digital track on the DVD menu (some discs default to the 2.0 Dolby Surround mix). But you're right, there is no way to toggle the MC-12 between 2.0 and 5.1 Logic 7, as the MC-12 will autodetect the format and load the appropriate effect for that source.


I remember just using the mode button on the remote to switch from L7 film to 5.1 L7. I'll try again.



It wouldn't be a problem with the Input Configuration. Smearing across the L-C-R is a symptom of a time alignment problem; most likely you need to fine tune the center speaker distance. A handy way to optimize this is to use the L7 Music mode while listening to a mono source (this will spread center-steered content across the L-C-R). While in this modes, try varying the center speaker distance setting a little bit above and below its current setting; when you get it right, you should hear the center image snap into focus, indicating your center is properly time-aligned with your left and right fronts.


I thought that everything sounded fine in the 5.1L7 mode. If I can find the Sniper scene again I will experiment this weekend.


A FAQ setup like Steve B. did for the Theta CBII would be very helpful.


Best regards,

Dave
 

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Quote:
Originally posted by DaveN


I remember just using the mode button on the remote to switch from L7 film to 5.1 L7. I'll try again.
This can't happen--one or the other mode will not be available, depending on the source content.

Quote:


I thought that everything sounded fine in the 5.1L7 mode. If I can find the Sniper scene again I will experiment this weekend.
In the 5.1 L7 mode, the center info is discrete and will likely be routed entirely to the center speaker, so you will not hear slight mismatches in time alignment. That is why I said to adjust using a mono PCM source (like a news program) through L7 Music (with Front Steering set to Music), because this will split the content across the three channels. Because the distribution is more pronounced in this mode, it is easier to hear (and adjust) time alignment problems.


Cheers,

Philip Brandes
 
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