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post #31 of 96 Old 08-23-2017, 09:48 AM - Thread Starter
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Originally Posted by LastButNotLeast View Post
The "problem" is that "small room" acoustics are very different from cinema dubbing stages. There is deep bass content in movies now that you'll never hear in a theater, but which can add dramatically to the experience in a home theater. But you have to go lower than 25Hz.
But now we're not talking about mid-bass, so, back to your point: when I added one MBM (Behringer 1200D), it made a big difference. When I tried to integrate a second, it just cancelled the effect of the first. So I use one.
Which is why measurements, experimentation, and patience are so important.
Michael
Hi Michael, thanks for the input. Is there any chance you have before MBM and after MBM FR we can see? I'm just curious as to how those look with what you describe.

Forgive the inconsistent fonts below that occurred with all the pasting I was doing.

I posed several questions on this to the mixing engineer. The engineer's response and descriptions are long and thorough, addressing much of what you mention and much more. If I wasn't bound to relay it only by paraphrasing it, I'd just post his entire comments. But I promised to abide by his conditions. I can quote SMPTE from his emails.

SMPTE says this about the LFE:

"The bandwidth of the low-frequency effects channel on a modern sound-track extends from 5 Hz to 120 Hz. A linear sub-woofer acoustic response is desirable from approximately, 25 Hz to 120 Hz. The 120-Hz sound-track cut-off is extremely steep, so a suitable sub-woofer need have little response above 125 Hz.

Many rooms have one or more dominant resonant frequencies within the low-frequency effects channel bandwidth. If not damped, this can lead to a characteristic low-frequency “ringing” every time the sound-track contains low-frequency information. Most cinema B-chain processors have at least one parametric equalizer for use within the sub-woofer bandpass. After adjustment, the response between 25 Hz and 120 Hz shall be flat to within + 3 dB. "

The engineer points out that many recordings of natural events that are layered together into final sound FX may have elements of VLF in them that are left in. He confirms that dubbing stages seek to be linear from 25Hz to 120Hz, they allow the subs and room roll off naturally below 25Hz. Therefore, there is no "spec" for below 25Hz, therefore no standard for monitoring VLF below that. So the reality is that some mixes and engineers are including VLF content, but what is there below 25Hz might be totally arbitrary and coincidental. My specific group of questions about VLF content were answered this way:

"To the question of whether there is information below 25Hz on the soundtrack, the answer is: Definitely.
To the question of whether it's intended or meant to be there, the answer is: Probably, but not always.
I was then prompted with another question which expands on the question of intention: Is the VFL meant to be the main point of sound? The answer is: Almost never/rarely."

The last comment is him speaking to the professional imperative that we as filmmakers always have.

So, if your system can reproduce content you find down deep, that's fine. Just know that it may be intentionally there, a happy surprise, or even undesirable to the filmmakers if it slipped through unnoticed.

I don't have a dog in the race, professionally, since my department is camera. I was given this advice:

"My advice for folks caught up in the enthusiasm over infrasonics would be to make sure they have a system that is replicating as best it can the performance and reference level calibrations found on the dubbing stages where the content is created and judged by the creative team."

That's what I follow. I'm happy with that (for now).




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post #32 of 96 Old 08-23-2017, 09:54 AM - Thread Starter
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@Scott Simonian --I remember you participating in that 2014 discussion.
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post #33 of 96 Old 08-23-2017, 10:00 AM
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Hahah! Yes and probably being my usual jerk-wad self.


My stances on ULF have soften over the years.
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post #34 of 96 Old 08-23-2017, 11:01 AM - Thread Starter
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Hahah! Yes and probably being my usual jerk-wad self.


My stances on ULF have soften over the years.
I think that my hearing would "soften" with much time spent in your room!
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post #35 of 96 Old 08-23-2017, 11:11 AM
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I think that my hearing would "soften" with much time spent in your room!
I have a volume control that happens to not be superglued down to 11.


But sometimes...
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post #36 of 96 Old 08-23-2017, 12:02 PM
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Hi...If the S1S subs are the current S1SEX, they are THX Ultra2 certified which means they will reach 20Hz for sure in a chamber. The older S1S, IIRC, were THX Ultra certified, and started unloading at about 35Hz presuming room gain. Still, they are capable of very high performance. Four of those in any room under 9000 cu feet would do very well with placement and EQ.

They are the older S1S the newer one uses the 2242H, the newer ones have more power handling than the older 2245H but the 2245H extends lower so I bet by the time I'm done with the NU3000DSP it'll play way down.


Looks like a fun project.
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What is that huge black processor in the middle of the image?
That is the Onkyo PR-RZ5100 preamp, I just got it. It is their top of the line.
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post #37 of 96 Old 08-23-2017, 12:16 PM
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Originally Posted by LastButNotLeast View Post
when I added one MBM (Behringer 1200D), it made a big difference. When I tried to integrate a second, it just cancelled the effect of the first. So I use one.
Have the cones facing each other in phase, or stacked if that isn't possible. Then this problem should be resolved.
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post #38 of 96 Old 08-23-2017, 12:51 PM
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It would be great if Hollywood could include the original cinema track on the disc's, or atleast an unmolested 7.1.X downsample. Instead of forcing enthusiasts to listen to the crappy "home mix" version aimed at people with Bose modules, the Dolby track only takes up like what, an extra ~500mb on the disc?

Most DIY'ers on this site are flat to 12-18hz, if not single digits; and have been for years (At least their subs, that is...)

My entry level Velodyne from 2001 was rated for 23hz and that was only $500 from BestBuy.
It's not like the infrasonic technology doesn't exist or is cutting edge.
Many SVS's hit 16hz, although not at the same level as a DIY system.

As for mid-bass, that is easily solvable by adding 3 1899 or some jbl/jtr's, or some pa-460's on the cheap-end.

As i already said: many people like to feel the U157 explosions killing them, and that takes a lot of wooferage, power and power-handling/efficiency. Most system's aren't beefy enough (at any frequency.)
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post #39 of 96 Old 08-23-2017, 01:20 PM - Thread Starter
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Originally Posted by BassThatHz View Post
It would be great if Hollywood could include the original cinema track on the disc's, or atleast an unmolested 7.1.X downsample. Instead of forcing enthusiasts to listen to the crappy "home mix" version aimed at people with Bose modules, the Dolby track only takes up like what, an extra ~500mb on the disc
I addressed this subject with the mixing facility engineer, too. In addition to the theatrical mixes they are one of the providers of the home theater mixes.

Generally the home theater mixes are created by the same mixers who create the main mixes. Sometimes, though, depending on schedules, a second mixer steps in. Often facilities bid the home theater as part of their package to get the main mix.

Usually these mixes are done in smaller rooms at the facility that are really just smaller dub stages or are stages that also do broadcast mixes. These rooms have dimensions that are more that of a large home space than a large cinema.

Many facilities use Genelec 1032s or similar in a near to midfield arrangement. Often the image is presented on a television rather than a projector for the home theater mixes. This means the speakers are not behind a movie screen (though may be soffit mounted behind grille cloth) and their locations reflect imaging around a tv screen which creates a different sonic imaging scenario when compared with behind the screen loudspeakers. Depending on the room however there may also be a behind the screen system available.

Besides the Genelec 1032s, facilities may cater to mixers who have a specific preference for a certain high quality home theater type speaker from any number of manufacturers.

We also asked if part of the home mix process is to check the LFE with and without bass management to make sure there isn't a low bass pile-up due to electrical vs acoustic summing. His response was that, yes, this is done and the mixers have the option to toggle in and out of bass managed or discrete mode as they see fit.
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post #40 of 96 Old 08-23-2017, 02:57 PM
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I addressed this subject with the mixing facility engineer, too. In addition to the theatrical mixes they are one of the providers of the home theater mixes.

Generally the home theater mixes are created by the same mixers who create the main mixes. Sometimes, though, depending on schedules, a second mixer steps in. Often facilities bid the home theater as part of their package to get the main mix.

Usually these mixes are done in smaller rooms at the facility that are really just smaller dub stages or are stages that also do broadcast mixes. These rooms have dimensions that are more that of a large home space than a large cinema.

Many facilities use Genelec 1032s or similar in a near to midfield arrangement. Often the image is presented on a television rather than a projector for the home theater mixes. This means the speakers are not behind a movie screen (though may be soffit mounted behind grille cloth) and their locations reflect imaging around a tv screen which creates a different sonic imaging scenario when compared with behind the screen loudspeakers. Depending on the room however there may also be a behind the screen system available.

Besides the Genelec 1032s, facilities may cater to mixers who have a specific preference for a certain high quality home theater type speaker from any number of manufacturers.

We also asked if part of the home mix process is to check the LFE with and without bass management to make sure there isn't a low bass pile-up due to electrical vs acoustic summing. His response was that, yes, this is done and the mixers have the option to toggle in and out of bass managed or discrete mode as they see fit.
The best example of a mix that was not messed with is from The Avengers: Age of Ultron, it has what seems to be an un-messed with mix.
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post #41 of 96 Old 08-23-2017, 03:33 PM
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Perhaps some of the 'lack' of midbass can be attributed to thermal compression, low directivity, early reflections.

Here's a few articles to ponder:

http://media.soundonsound.com/sos/ju...s/monitors.asp

http://media.soundonsound.com/sos/ju.../monitors2.asp

An acoustically large source will not sound the same as a smaller source, even if the frequency response is the same.

Ask your doctor if DIY is right for you. Side effects of DIY may include anxiety, elevated blood pressure, lightheadedness, rapid heartbeat, skeletal muscle flaccidity, euphoria, psychological dependence, insomnia, confusion, blurred vision, implusivity, uncontrolled or repeated movements.
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post #42 of 96 Old 08-23-2017, 08:24 PM
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Originally Posted by Cam Man View Post
Hi Michael, thanks for the input. Is there any chance you have before MBM and after MBM FR we can see? I'm just curious as to how those look with what you describe.
Sorry, I don't keep old data.

Michael

Did you really need to quote that entire post in your reply?
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post #43 of 96 Old 08-26-2017, 12:22 PM
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My condolences.

You shoulda went 4-way active sealed. My mains are flat from 2Hz to 40kHz


I'm 100% sure that if I took it outside the sweep would be even smoother...
and that's just my mains, my subs and MBM's are beefier (and ran about 15db hotter...)

Who wants to run their LCR's 15db hot @4khz just to get some more mid-bass, when you CAN HAVE dedicated MBM's for that task?

The tonality of the LCR needs to be flat from DC to Infinity, otherwise things will sound "rolled off", or bloated if you try to apply a house curve to the LCR's or try force ported's below their tuning.

Some people like their bass to kill them. Even a single SEOS can kill your ears, but try killing your ears at 20hz... that's no easy task, even for 8 horned 18's! Never enough bass. MOAR!



Are your mains ported? at 50hz?
As I understand, ported boxes have a phase shift below tuning, so I wouldn't be surprised that forcing it to play to DC might cause all sorts of phase/SPL/driver issues. Sealed doesn't have this issue, it only bottoms out earlier. Everyone needs 32 sealed 32's. Just add more... Problem solved!
Please share if you would. You have your monster mains tuned flat. What range do your mbms play and how many db over the flat mains? Pure curiosity as i see u knowing more than most w your capability. Does the added midbass cause any other frequencirs to be harder to hear?
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post #44 of 96 Old 08-26-2017, 12:30 PM
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We also asked if part of the home mix process is to check the LFE with and without bass management to make sure there isn't a low bass pile-up due to electrical vs acoustic summing. His response was that, yes, this is done and the mixers have the option to toggle in and out of bass managed or discrete mode as they see fit.
If I am going to run the LR channels and LFE to my MBM's would this create "acoustic summing" referenced above?

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post #45 of 96 Old 08-26-2017, 12:34 PM
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If I am going to run the LR channels and LFE to my MBM's would this create "acoustic summing" referenced above?
How is that possible to run both LR and LFE to the MBM? Or do you mean you will switch between them?

Edit I think I see what you were saying is you will just run LFE to your MBM and cross over the LR as normal.

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post #46 of 96 Old 08-26-2017, 12:37 PM
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Originally Posted by Cam Man View Post
I addressed this subject with the mixing facility engineer, too. In addition to the theatrical mixes they are one of the providers of the home theater mixes.

Generally the home theater mixes are created by the same mixers who create the main mixes. Sometimes, though, depending on schedules, a second mixer steps in. Often facilities bid the home theater as part of their package to get the main mix.

Usually these mixes are done in smaller rooms at the facility that are really just smaller dub stages or are stages that also do broadcast mixes. These rooms have dimensions that are more that of a large home space than a large cinema.

Many facilities use Genelec 1032s or similar in a near to midfield arrangement. Often the image is presented on a television rather than a projector for the home theater mixes. This means the speakers are not behind a movie screen (though may be soffit mounted behind grille cloth) and their locations reflect imaging around a tv screen which creates a different sonic imaging scenario when compared with behind the screen loudspeakers. Depending on the room however there may also be a behind the screen system available.

Besides the Genelec 1032s, facilities may cater to mixers who have a specific preference for a certain high quality home theater type speaker from any number of manufacturers.

We also asked if part of the home mix process is to check the LFE with and without bass management to make sure there isn't a low bass pile-up due to electrical vs acoustic summing. His response was that, yes, this is done and the mixers have the option to toggle in and out of bass managed or discrete mode as they see fit.
Ty for posting this discussion! Its great to get some definitive answers on how and why. Great thread and discussion.
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post #47 of 96 Old 08-26-2017, 12:38 PM
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How is that possible to run both LR and LFE to the MBM? Or do you mean you will switch between them?

Edit I think I see what you were saying is you will just run LFE to your MBM and cross over the LR as normal.
it would be a Y adapter from my LR pre-outs to a Y adapter with my LFE. The signal being sent would be LFE/Left-front/Right-front. This way I could get 45Hz to 160Hz. I don't want to run my LR crossovers at 40Hz. They can theoretically handle it but I'm not sure I'm into that. If I do keep my crossoers at 40 then I can run the MBM's through the LR pre-outs and then set up an LPF around 140Hz.

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post #48 of 96 Old 08-26-2017, 12:39 PM - Thread Starter
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If I am going to run the LR channels and LFE to my MBM's would this create "acoustic summing" referenced above?
I'll get a detailed answer for you.
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post #49 of 96 Old 08-26-2017, 02:00 PM - Thread Starter
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it would be a Y adapter from my LR pre-outs to a Y adapter with my LFE. The signal being sent would be LFE/Left-front/Right-front. This way I could get 45Hz to 160Hz. I don't want to run my LR crossovers at 40Hz. They can theoretically handle it but I'm not sure I'm into that. If I do keep my crossoers at 40 then I can run the MBM's through the LR pre-outs and then set up an LPF around 140Hz.
I know I'm kind of drive-by shooting to get an answer to your question. Forgive me. Here is the response from my colleague who was involved in the discussion with the mixing engineer. He used the acronym "SSP" meaning surround sound processor in your AVR/AVC.

See what you can make of that for now. Forgive, but I don't have the time to dive in with you today.

"The short answer is that what he describes would not be acoustic summing in the sense I was using the term, since he would be sending an electrical sum of the L/R main channels and LFE to subwoofers and MBMs.

Based on his description, I'm not entirely sure what his goal is. It seems that he is concerned about crossing his L/R mains at 45 Hz due to concerns over the output capability. If this is the case, the preferred solution is typically to raise the crossover frequency to something like 80 Hz. If this is undesirable for some reason, he can add another woofer cabinet to the L/R by using an external crossover. He would set the SSP crossover to 45 Hz, then run the L/R outputs into the external crossover which is set to 160 Hz. The high-pass from the external crossover would go the L/R main amplifiers, while the low-pass would go to the L/R MBM amplifiers. He doesn't mention the center; if it is the same type speaker as the L/R, something similar should be done to it. The center typically handles more power than the L/R.

LFE would be handled by the subwoofers, and the bandwidth on the top end (typically 80 or 120 Hz) would be set by the SSP (most SSPs allow the LFE low-pass to be adjusted independently of the mains crossovers).

We did this for a large dealer showroom where the dealer wanted a Triad THX-certified sound system. The Triad Platinum LCR would have easily handled the room, but was not THX. The Gold LCR was THX, but lacked the woofer power for the room size. To remedy this, we inserted a 10" Bronze subwoofer in the baffle underneath each Gold LCR with a crossover at 120 Hz. The main subwoofer crossover for the whole system remained at 80 Hz, and the LFE channel was low-passed at 80 Hz."
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post #50 of 96 Old 08-26-2017, 05:46 PM
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it would be a Y adapter from my LR pre-outs to a Y adapter with my LFE. The signal being sent would be LFE/Left-front/Right-front. This way I could get 45Hz to 160Hz. I don't want to run my LR crossovers at 40Hz. They can theoretically handle it but I'm not sure I'm into that. If I do keep my crossoers at 40 then I can run the MBM's through the LR pre-outs and then set up an LPF around 140Hz.
I can tell you from experience that if you try combining your L&R with a Y adapter it will not work and then adding in the LFE will only make it worse and possibly damage something. Also it will make all your stereo channels mono or that is what happened when I tried it. I didnt realize it until I tried listening to a stereo imaging test track and it was all mono. I was like what the heck? I figured out why don't Y 2 stereo channels together

This will get into it more. http://www.rane.com/note109.html

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post #51 of 96 Old 08-27-2017, 08:14 AM
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I can tell you from experience that if you try combining your L&R with a Y adapter it will not work and then adding in the LFE will only make it worse and possibly damage something. Also it will make all your stereo channels mono or that is what happened when I tried it. I didnt realize it until I tried listening to a stereo imaging test track and it was all mono. I was like what the heck? I figured out why don't Y 2 stereo channels together

This will get into it more. http://www.rane.com/note109.html
You would need a mixer likely to take care of this.
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post #52 of 96 Old 08-27-2017, 09:59 AM
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You would need a mixer likely to take care of this.
Yeah, the article I linked explains what is needed. I didn't buy anything as I was just messing with my desktop computer setup a long time ago and trying to get a mono signal with parts I had on hand. I see they sell combiner boxes cheap, mixers are a little more money but I didn't look into it as I didn't need it.

From what I understand there is still a negative effect to your stereo separation from using those boxes.

"this Note has to do with applications where you want to sum two outputs together and you want to continue to use each of these outputs separately. If all you want to do is sum two outputs together and use only the summed results (the usual application), skip this section.

The problem arising from using all three outputs (the two original and the new summed output) is one of channel separation, or crosstalk. If the driving unit truly has zero output impedance, than channel separation is not degraded by using this summing box. However, when dealing with real-world units you deal with finite output impedances (ranging from a low of 47 ohms to a high of 600 ohms). Even a low output impedance of 47 ohms produces a startling channel separation spec of only 27 dB, i.e., the unwanted channel is only 27 dB below the desired signal. (Technical details: the unwanted channel, driving through the summing network, looks like 1011.3 ohms driving the 47 ohms output impedance of the desired channel, producing 27 dB of crosstalk.)"

These are what I came across though with a quick google. Not sure how well they will work for combining 3 sources like TJ wants to do. @tjcinnamon if you try it let us know how it works for you.

https://www.amazon.com/Galaxy-Audio-.../dp/B005GJCA6M

https://www.amazon.com/Galaxy-Audio-...6XTBYVBDQVJVY9

http://www.mcmelectronics.com/product/555-0678

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post #53 of 96 Old 08-27-2017, 06:41 PM
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I know I'm kind of drive-by shooting to get an answer to your question. Forgive me. Here is the response from my colleague who was involved in the discussion with the mixing engineer. He used the acronym "SSP" meaning surround sound processor in your AVR/AVC.

See what you can make of that for now. Forgive, but I don't have the time to dive in with you today.
This is great and certainly opens up some possibilities.

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"The short answer is that what he describes would not be acoustic summing in the sense I was using the term, since he would be sending an electrical sum of the L/R main channels and LFE to subwoofers and MBMs.

Based on his description, I'm not entirely sure what his goal is. It seems that he is concerned about crossing his L/R mains at 45 Hz due to concerns over the output capability. If this is the case, the preferred solution is typically to raise the crossover frequency to something like 80 Hz.
@bscool had a great point, Given the placement of these MBM's (which are basically 12" subs with an HPF at 40Hz), I think running the LFE and R to the right MBM and the LFE and L to the left MBM would be desired.

I am concerned about running my Paradigm 75F's with a 40Hz crossover. They can handle 50 really well, I don't trust them at 40Hz. I would prefer to run the crossover at 80Hz which I why I was thinking of putting the LFE in conjunction with the front channel

MBM signal = ((LFE 20 to 120Hz) + (crossed over LCR 20 to 80Hz) + (L or R signal 80 to 200Hz)) with LPF at 160 and HPF at 40Hz. Total signal received is 40Hz to 160Hz

without the LFE, I'll lose some content that would traditionally go to a higher signal sub, without the LR content I lose everything above the 80Hz crossover. If I had to choose, I think I would get rid of the LFE channel. But the goal here is to get 40 to 160Hz.

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If this is undesirable for some reason, he can add another woofer cabinet to the L/R by using an external crossover. He would set the SSP crossover to 45 Hz, then run the L/R outputs into the external crossover which is set to 160 Hz. The high-pass from the external crossover would go the L/R main amplifiers, while the low-pass would go to the L/R MBM amplifiers. He doesn't mention the center; if it is the same type speaker as the L/R, something similar should be done to it. The center typically handles more power than the L/R.

LFE would be handled by the subwoofers, and the bandwidth on the top end (typically 80 or 120 Hz) would be set by the SSP (most SSPs allow the LFE low-pass to be adjusted independently of the mains crossovers).
The idea of an external crossover is a good one and opens some possibilities to me. The primary issue for me would be that I don't have my fronts going to an external amp. The MBM subs are going AVR, AMP, SUBs whereas my fronts are AVR to speaker. Meaning putting them on an external crossover would be tough. So my input signal for the mains is Speaker wire and for the subs is an RCA pre-out.

I'll mull this solution over.

I'd be interested if it's possible to mix both the LFE and Mains together? With my AVR anything below the crossover goes to the LFE.

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post #54 of 96 Old 08-27-2017, 06:46 PM
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I can tell you from experience that if you try combining your L&R with a Y adapter it will not work and then adding in the LFE will only make it worse and possibly damage something. Also it will make all your stereo channels mono or that is what happened when I tried it. I didnt realize it until I tried listening to a stereo imaging test track and it was all mono. I was like what the heck? I figured out why don't Y 2 stereo channels together

This will get into it more. http://www.rane.com/note109.html
That's good advice. Given the placement of the MBMs (12" subs @ 40+Hz) they are right next to my mains. So I wouldn't mix the LR but I am considering putting an adapter for the L+LFE and R+LFE respectively.

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post #55 of 96 Old 08-27-2017, 06:57 PM
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Yeah, the article I linked explains what is needed. I didn't buy anything as I was just messing with my desktop computer setup a long time ago and trying to get a mono signal with parts I had on hand. I see they sell combiner boxes cheap, mixers are a little more money but I didn't look into it as I didn't need it.

From what I understand there is still a negative effect to your stereo separation from using those boxes.

"this Note has to do with applications where you want to sum two outputs together and you want to continue to use each of these outputs separately. If all you want to do is sum two outputs together and use only the summed results (the usual application), skip this section.

The problem arising from using all three outputs (the two original and the new summed output) is one of channel separation, or crosstalk. If the driving unit truly has zero output impedance, than channel separation is not degraded by using this summing box. However, when dealing with real-world units you deal with finite output impedances (ranging from a low of 47 ohms to a high of 600 ohms). Even a low output impedance of 47 ohms produces a startling channel separation spec of only 27 dB, i.e., the unwanted channel is only 27 dB below the desired signal. (Technical details: the unwanted channel, driving through the summing network, looks like 1011.3 ohms driving the 47 ohms output impedance of the desired channel, producing 27 dB of crosstalk.)"

These are what I came across though with a quick google. Not sure how well they will work for combining 3 sources like TJ wants to do. @tjcinnamon if you try it let us know how it works for you.

https://www.amazon.com/Galaxy-Audio-.../dp/B005GJCA6M

https://www.amazon.com/Galaxy-Audio-...6XTBYVBDQVJVY9

http://www.mcmelectronics.com/product/555-0678
There are impedance factors with just the RCA signal? I don't know much about that kind of stuff... yet.

Would I still need one of these devices if I were to combine 2 signals (LFE+R) and (LFE+L) respectively.

NAD 758 v3 with Dirac 7.4.4 + Rotel 976 + Panamax M5300-PM
Paradigm Prestige 75F's + 55C; 8x Paradigm CI Pro P65-R's
DIY MBMs: VRK Build thread + 2x Rotel 981 (bridged)
Sub: 2x Rythmik LVX12 + MiniDSP
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post #56 of 96 Old 08-27-2017, 07:37 PM
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Originally Posted by tjcinnamon View Post
There are impedance factors with just the RCA signal? I don't know much about that kind of stuff... yet.

Would I still need one of these devices if I were to combine 2 signals (LFE+R) and (LFE+L) respectively.
Yeah from what I understand, from the article "a wye-connector used to mix two signals into one is being abused and may even damage the equipment involved.

Here is the rule: Outputs are low impedance and must only be connected to high impedance inputs -- never, never tie two outputs directly together -- never. If you do, then each output tries to drive the very low impedance of the other, forcing both outputs into current-limit and possible damage. As a minimum, severe signal loss results."

And that is what you would be doing by mixing R with LFE and L with LFE respectively. You are still mixing two low impedance output signals.

And if I am understanding correctly is still going to have a negative effect on the stereo separation. How much or how noticeable will it be? I do not know. At least if I am understanding it correctly from the article "The problem arising from using all three outputs (the two original and the new summed output) is one of channel separation or crosstalk" I think the LFE channel will still effect the L and R since you are combining the LFE with each channel separately. But I could be wrong but that is the way I understand it.


What about using the center channel + LFE since it is mono anyway and you don't have to worry about stereo cross talk issues? I would still use one of the combiner/mixer boxes.

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post #57 of 96 Old 08-27-2017, 07:53 PM
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Yeah from what I understand, from the article "a wye-connector used to mix two signals into one is being abused and may even damage the equipment involved.

Here is the rule: Outputs are low impedance and must only be connected to high impedance inputs -- never, never tie two outputs directly together -- never. If you do, then each output tries to drive the very low impedance of the other, forcing both outputs into current-limit and possible damage. As a minimum, severe signal loss results."

And that is what you would be doing by mixing R with LFE and L with LFE respectively. You are still mixing two low impedance output signals.

And if I am understanding correctly is still going to have a negative effect on the stereo separation. How much or how noticeable will it be? I do not know. At least if I am understanding it correctly from the article "The problem arising from using all three outputs (the two original and the new summed output) is one of channel separation or crosstalk" I think the LFE channel will still effect the L and R since you are combining the LFE with each channel separately. But I could be wrong but that is the way I understand it.


What about using the center channel + LFE since it is mono anyway and you don't have to worry about stereo cross talk issues? I would still use one of the combiner/mixer boxes.
I'm happy to use one of those mixers/combines.

How would center+LFE be different than Left+LFE?
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post #58 of 96 Old 08-27-2017, 08:19 PM
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I'm happy to use one of those mixers/combines.

How would center+LFE be different than Left+LFE?

My thought is the LFE is mono and center is mono, where left and right are stereos and you will be combining the left with lLFE and then the right with LFE so that will reduce the stereo separation between left and right since they are getting mixed with the LFE. But my line of thinking might be off. Maybe it wouldn't matter, you will have to try it and see if combining them with LFE effects it.

Use something like the test here or other test tracks and see what happens. Further down the page are 5.1 channel tests. https://www2.iis.fraunhofer.de/AAC/multichannel.html

And and the center channel is not mono but I am not sure how else to try to explain it and maybe it would be worse mixing the LFE and center.

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Last edited by bscool; 08-27-2017 at 08:23 PM.
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post #59 of 96 Old 08-28-2017, 11:10 AM
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Great discussion here!

Here's my input: Objectively my basement HT's FR has always measured relatively flat throughout the 30-120hz range, whether it be my Fusion, 15 towers running full range or with my LCR's xo @ 80hz to 4 x Marty's with HST18's upfront.

Subjectively, I noticed the lack of sound quality when I accidentally ran my f15T full range while listening to music. I began to experiment with the pro audio drivers ala pa460 by integrating them with the pa460's and the SQ in my experience was improved due to "quicker/punchier" bass.

In my case, I preferred to have tons and good quality 40hz+ which is I've implement nearfield ported pa460 in my setup - I can now independently adjust the midbass to taste without cranking the MV.
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post #60 of 96 Old 08-28-2017, 11:28 AM
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Please share if you would. You have your monster mains tuned flat. What range do your mbms play and how many db over the flat mains? Pure curiosity as i see u knowing more than most w your capability. Does the added midbass cause any other frequencirs to be harder to hear?
Sometimes i actviate my mbm's and sometimes i don't, usually i only activate them for horror or action or really loud music. I usually run them 5-15db hot, depending on source. As for the range I use 30-300hz (sealed).

For critical-listening I leave them off.
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