I'm done with the SMS-1, it limits the output of my Submersives - AVS Forum
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post #1 of 58 Old 01-02-2013, 03:15 PM - Thread Starter
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At our GTG the other night we found out something very interesting. We were testing the output capabilities of a single Submersive and something didn't seem quite right. Everyone has heard the Submersive many times and felt we should have been getting more output.

So, someone had the idea to remove the SMS-1 from the chain. Wow, huge difference.

Now, I didn't want to post anything definitive until I had some more time to test it out, because I knew that the SMS-1 needed to be close to 15 on it's volume, and we were well below it the other night. So, today I adjusted the gains on one of my Submersives so that it would be level matched with the speakers when the SMS-1 volume is at 15. I played to same scene, each time upping the volume until the db meter stopped going up.

I reached that point of no more db increase no matter how high the volume was pushed at reference on the master volume and the sub at +10.

Here was the readings from the omnimic using C weighted Slow:

PEAK: 117.4
MAX: 107


Next, I took the SMS-1 out of the chain and re-calibrated the speakers to match the Submersive.

Once again, I used the same scene (BTW, elevator drop/uzi scene from Underworld)

PEAK: 124.1
MAX: 113.3


That is a HUGE difference, and it is very obvious subjectively too.

Now, I say that I'm done with it the SMS-1, I may still use it for music but it is clear you should not use it for movies IMO.

You guys that have the sms-1 should test yours out, maybe it's just my unit who knows.
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post #2 of 58 Old 01-02-2013, 03:39 PM - Thread Starter
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I checked it multiple times to be sure....

master volume reference - check
sub out 10 hot on receiver settings - check
sms-1 volume 15 - check
speakers level same volume compared to subs with our without sms-1 using receiver test tones - check

I also went into the sms-1 menu to make sure I hadn't accidentally turned on a HPF or something, nope...
While I was in there I turned the night volume to 100 percent just to make sure it hadn't been activated some how.

Measured the scene one more time, same results. frown.gif

It's too bad, I like using the sms-1 for using different presets depending on my mood... oh well. Probably shouldn't have started this thread since I may end up selling it.... tongue.gif
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post #3 of 58 Old 01-02-2013, 06:14 PM
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carp why is your sub out on the receiver +10? That may be input clipping the sms-1?!?

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post #4 of 58 Old 01-02-2013, 08:09 PM
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Interesting. Funny enough when audyssey does it's thing with my setup it basically lowers the entire sub band by about 6db or so. I have to compensate by bumping the sub levels up quite a bit since I like them overall a bit hot.
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post #5 of 58 Old 01-02-2013, 08:20 PM - Thread Starter
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Quote:
Originally Posted by Archaea View Post

carp why is your sub out on the receiver +10? That may be input clipping the sms-1?!?

That's not what I'm saying. I meant the sub is being played 10 hot, not +10 on the receiver. When I calibrate I always calibrate to -10 with the subs, so 10 hot is 0 on the sub out volume.
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post #6 of 58 Old 01-02-2013, 09:25 PM
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Carp, strange you mentioned this. I just removed the sms-1 from my system because I wanted to see what XT32 would do with the 2 separate sub outs on my Integra as opposed to using the 1 SMS-1 sub in and daisy chaining my submersives. Now I did move my subs to new positions but damn my rooms a rocking now when I crank the bass up.

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post #7 of 58 Old 01-03-2013, 12:01 AM
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This is strange as I just recently demoed my subs with the SMS-1 in the loop and then took it out of the loop and didn't notice any change in output. It was a home theater demo as well with WoW pod scene, FOTP barrell roll, all the familiar bass torture tracks. I am going to try it again this week if I get home early enough.

Since both people who have noticed a difference both have submersives could there be a correlation there?

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post #8 of 58 Old 01-03-2013, 03:12 AM
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Quote:
Originally Posted by carp View Post

Now, I didn't want to post anything definitive until I had some more time to test it out, because I knew that the SMS-1 needed to be close to 15 on it's volume, and we were well below it the other night. So, today I adjusted the gains on one of my Submersives so that it would be level matched with the speakers when the SMS-1 volume is at 15. I played to same scene, each time upping the volume until the db meter stopped going up.
I reached that point of no more db increase no matter how high the volume was pushed at reference on the master volume and the sub at +10.
The SMS-1's level is at Unity Gain, (output = input) when the Volume is set to 15... WITH NO EQ APPLIED. However, if you add some boosts and cuts, you need to reset the volume for Unity Gain. 15 is probably no longer the Unity Gain point. If most of your EQ bands are cuts, you need to raise the overall volume to compensate. The best way to test it is to play an LF noise signal and switch the EQ in and out while checking the levels with an SPL meter.

Before you remove your SMS-1, be sure you have the correct level setting. It's probably NOT 15.

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post #9 of 58 Old 01-03-2013, 06:30 AM
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Quote:
Originally Posted by mjaudio View Post

This is strange as I just recently demoed my subs with the SMS-1 in the loop and then took it out of the loop and didn't notice any change in output. It was a home theater demo as well with WoW pod scene, FOTP barrell roll, all the familiar bass torture tracks. I am going to try it again this week if I get home early enough.

Since both people who have noticed a difference both have submersives could there be a correlation there?


do you play your equipment 10dB above reference like carp? tongue.gif

the problem seemed legit, but at levels far far far above normal.

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post #10 of 58 Old 01-03-2013, 08:29 AM
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Quote:
Originally Posted by carp View Post


I reached that point of no more db increase no matter how high the volume was pushed at reference on the master volume and the sub at +10.
Here was the readings from the omnimic using C weighted Slow:
PEAK: 117.4
MAX: 107
Next, I took the SMS-1 out of the chain and re-calibrated the speakers to match the Submersive.
Once again, I used the same scene (BTW, elevator drop/uzi scene from Underworld)
PEAK: 124.1
MAX: 113.3
 

 

Quote:
Originally Posted by Archaea View Post


do you play your equipment 10dB above reference like carp? tongue.gif
the problem seemed legit, but at levels far far far above normal.

Actually, Carps output at +10db wasn't even above reference. His max output for that particular scene was 113.3db. Reference is at least 115db. 

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post #11 of 58 Old 01-03-2013, 08:33 AM
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Is this the difference between having EQ engaged and not engaged? Did you add EQ back in when you removed the SMS-1? That higher peak could just be that, a peak in the response where the SMS-1 did not have that. I always get lower spl numbers with EQ engaged and then turn the gain up if I want the same numbers.

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post #12 of 58 Old 01-03-2013, 08:54 AM
 
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Quote:
Originally Posted by dominguez1 View Post

Actually, Carps output at +10db wasn't even above reference. His max output for that particular scene was 113.3db. Reference is at least 115db.

My understanding, reference for subwoofers is 105dB with an additional +10dB headroom for subwoofers so the subwoofer system needs to be 115db capable but only expected to hit 105dB. Love flexible standards.

At home we have a "temple" standard. At ~95dB room volume (-10db on the volume control), the wife places her fingers on her temples. Hence creation of the "temple" standard. tongue.gif

(And why are they called "temples?")

-
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post #13 of 58 Old 01-03-2013, 09:07 AM - Thread Starter
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Quote:
Originally Posted by craig john View Post

The SMS-1's level is at Unity Gain, (output = input) when the Volume is set to 15... WITH NO EQ APPLIED. However, if you add some boosts and cuts, you need to reset the volume for Unity Gain. 15 is probably no longer the Unity Gain point. If most of your EQ bands are cuts, you need to raise the overall volume to compensate. The best way to test it is to play an LF noise signal and switch the EQ in and out while checking the levels with an SPL meter.
Before you remove your SMS-1, be sure you have the correct level setting. It's probably NOT 15.
Craig

Hey Craig, the preset I used was #6 which doesn't apply any eq, that way I could be sure that I was measuring the same frequency response as when I took the SMS-1 out of the chain.

Now, the other presets had some cuts and boosts (mostly cuts, very little boosting) but I wasn't using any of them for this comparison. I double checked to make sure no HPF was on and absolutely no eq applied.
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post #14 of 58 Old 01-03-2013, 09:10 AM - Thread Starter
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Craig, are you still using your sms-1? When you get a chance can you check it sometime make sure it's not happening to you?
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post #15 of 58 Old 01-03-2013, 09:11 AM - Thread Starter
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Quote:
Originally Posted by MKtheater View Post

Is this the difference between having EQ engaged and not engaged? Did you add EQ back in when you removed the SMS-1? That higher peak could just be that, a peak in the response where the SMS-1 did not have that. I always get lower spl numbers with EQ engaged and then turn the gain up if I want the same numbers.

Yes I was thinking the same thing, I better make sure I'm comparing apples to apples so I went with no eq at all.
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post #16 of 58 Old 01-03-2013, 09:14 AM - Thread Starter
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Quote:
Originally Posted by dominguez1 View Post

Actually, Carps output at +10db wasn't even above reference. His max output for that particular scene was 113.3db. Reference is at least 115db. 

It's kind of cool in a way though, I recently had my Submersives stacked in the same corner but today I'm shipping one off that I just sold. Now that I discovered this issue and have removed the SMS-1, my output is back to where it would be with dual Submersives stacked when I was using the SMS-1.
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post #17 of 58 Old 01-03-2013, 10:48 AM
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Quote:
Originally Posted by BeeMan458 View Post


My understanding, reference for subwoofers is 105dB with an additional +10dB headroom for subwoofers so the subwoofer system needs to be 115db capable but only expected to hit 105dB. Love flexible standards.
At home we have a "temple" standard. At ~95dB room volume (-10db on the volume control), the wife places her fingers on her temples. Hence creation of the "temple" standard. tongue.gif
(And why are they called "temples?")
-

I believe that 105db is at sustained levels of bass, but each channel should be able to peak up to 115db in the bass region. So in theory, all 7 channels could have peaks of 115db. If you bass manage (crossover) the bass of all of your channels to the sub(s), I believe the theoretical peak output for your subs go to 121db if all channels required that output at the same time.

 

So that would be the theoretical output of what your sub system should be able to reproduce for those brief dynamic peaks.

 

Someone correct me if I'm wrong...

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post #18 of 58 Old 01-03-2013, 10:52 AM - Thread Starter
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Quote:
Originally Posted by dominguez1 View Post

I believe that 105db is at sustained levels of bass, but each channel should be able to peak up to 115db in the bass region. So in theory, all 7 channels could have peaks of 115db. If you bass manage (crossover) the bass of all of your channels to the sub(s), I believe the theoretical peak output for your subs go to 121db if all channels required that output at the same time.

So that would be the theoretical output of what your sub system should be able to reproduce for those brief dynamic peaks.

Someone correct me if I'm wrong...

That's how I've always heard it Dom. What I don't know is which numbers to go on with the onmimic, peak or max?
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post #19 of 58 Old 01-03-2013, 10:56 AM
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Originally Posted by carp View Post


That's how I've always heard it Dom. What I don't know is which numbers to go on with the onmimic, peak or max?

Max. This is what your typical SPL meter reads. It is an RMS (root mean squared) measurement and is what we 'hear'.

 

Peak is the highest amplitude of the waveform, but has no time variable associated with it.

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post #20 of 58 Old 01-03-2013, 11:19 AM
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Quote:
Originally Posted by carp View Post

Craig, are you still using your sms-1? When you get a chance can you check it sometime make sure it's not happening to you?
If I am not mistaken I bought the SMS-1 that Craig was using. He was no longer using it since XT32 did the job well enough. Without getting into the details(Craig could explain the why better than me), I am using the SMS-1 with a SubMersive HP. We are using it to cut a MAJOR peak I have in my room that Audyessy was just making worse. I was able to watch a few movies without the SMS-1(before I knew I needed it). With the SMS-1 in the chain, I personally can not detect any "weakness" in the bass with my HP. I think we used preset 4 as a starting point because that looked pretty good. I am not saying that my case is the rule. In fact, I would say that I think my room is the exception for a lot of things. But for me, The SMS-1 works well and I can't say that I think it is confining the output of my HP. But, as always, YMMV.

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post #21 of 58 Old 01-03-2013, 11:27 AM
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Originally Posted by Archaea View Post

carp why is your sub out on the receiver +10? That may be input clipping the sms-1?!?
That or clipping the output of the receiver itself.
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post #22 of 58 Old 01-03-2013, 11:29 AM
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Quote:
Originally Posted by carp View Post

It's kind of cool in a way though, I recently had my Submersives stacked in the same corner but today I'm shipping one off that I just sold. Now that I discovered this issue and have removed the SMS-1, my output is back to where it would be with dual Submersives stacked when I was using the SMS-1.

Darn... Guess you are just going to have to tough it out with the 8 18's your going to be rocking soon.

Thinking about your set up, each piece of gear in your chain is applying some sort of EQ. XT-32 to SMS-1 to SubM, each of which can apply seperate EQ settings.

My question with the SMS is.... Does it apply a 6db cut when introduced into your signal chain from the onset? Meaning, if you were to "boost" a band +6db are you simply allowing the full signal from your AVR? Or is setting 6 intended to allow raw pass through?

I have no complaints from my SMS on this end, but I need to save up a but more for an OM in the near future.

I can say with confidence that the raw response of my LMS-U's definitely benifits from the SMS-1 implementation.
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post #23 of 58 Old 01-03-2013, 11:31 AM
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A few questions...

1) What receiver do you have?
2) What was the master volume set to when you noticed the subwoofer was no longer getting any louder
3) What was the SW channel output trim set to?
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post #24 of 58 Old 01-03-2013, 11:34 AM
 
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Quote:
Originally Posted by dominguez1 View Post

I believe that 105db is at sustained levels of bass, but each channel should be able to peak up to 115db in the bass region. So in theory, all 7 channels could have peaks of 115db. If you bass manage (crossover) the bass of all of your channels to the sub(s), I believe the theoretical peak output for your subs go to 121db if all channels required that output at the same time.

So that would be the theoretical output of what your sub system should be able to reproduce for those brief dynamic peaks.

Someone correct me if I'm wrong...

I'm not correcting you. My understanding, speakers are set to an 85dB sustained "AVERAGE" with +20dB headroom and subs (LFE channel information) are +10dB higher at 95dB plus 20dB for headroom or "peaks.".

THX Reverence Level.

"Experience Studio Clarity: THX Certified Receivers reproduce studio Reference Level, 85dB SPL with 20dB of headroom."

See: "Maximum Level"

"The 0 dB reference level represents an average 85 dB SPL and a maximum 105 dB SPL. The LFE (Low Frequency Effects) channel used by AC3 (Dolby Digital) and DTS is +10 dB higher. This means that the maximum output for bass peaks is 115 dB SPL. The purpose of the +10 dB gain for the LFE channel is to increase the dynamic range of bass events such as explosions, crashes, punches, and rumbles. This means when the volume is set to 0 dB that the subwoofer could be asked to produce an output of 115 dB SPL"

-.
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post #25 of 58 Old 01-03-2013, 11:35 AM - Thread Starter
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Quote:
Originally Posted by Stereodude View Post

That or clipping the output of the receiver itself.

Dammit guys I said this already but I'll try again, MY RECEIVER IS AT -10 WHEN CALIBRATED, so that means it is at 0 when the sub is 10 dbs hot.

My first post meant I was running the subs 10 dbs hot, NOT that the sub out volume was at +10 on the receiver.

Ok, that sounded angry - sorry!! eek.gifsmile.gif
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post #26 of 58 Old 01-03-2013, 11:40 AM
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Quote:
Originally Posted by carp View Post

Dammit guys I said this already but I'll try again, MY RECEIVER IS AT -10 WHEN CALIBRATED, so that means it is at 0 when the sub is 10 dbs hot.
My first post meant I was running the subs 10 dbs hot, NOT that the sub out volume was at +10 on the receiver.
Ok, that sounded angry - sorry!! eek.gifsmile.gif
That doesn't mean you're not clipping your LFE signal somewhere in the chain. For example, I can clip the SW output of my Pioneer Elite SC-05 with the SW level trim at 0 and the master volume at 0. You're probably clipping the input of the SMS-1 (or it's clipping its output), but it can start at the receiver's output.
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post #27 of 58 Old 01-03-2013, 11:46 AM
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Quote:
Originally Posted by BeeMan458 View Post

"The 0 dB reference level represents an average 85 dB SPL and a maximum 105 dB SPL. The LFE (Low Frequency Effects) channel used by AC3 (Dolby Digital) and DTS is +10 dB higher. This means that the maximum output for bass peaks is 115 dB SPL. The purpose of the +10 dB gain for the LFE channel is to increase the dynamic range of bass events such as explosions, crashes, punches, and rumbles. This means when the volume is set to 0 dB that the subwoofer could be asked to produce an output of 115 dB SPL".
Yes, but considering bass management and 7 channels at 105dB and a subwoofer at 115dB you get 117.3dB according to the dB calculator on this page.
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post #28 of 58 Old 01-03-2013, 11:52 AM
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Quote:
Originally Posted by dominguez1 View Post

Quote:
Originally Posted by BeeMan458 View Post

My understanding, reference for subwoofers is 105dB with an additional +10dB headroom for subwoofers so the subwoofer system needs to be 115db capable but only expected to hit 105dB. Love flexible standards.

At home we have a "temple" standard. At ~95dB room volume (-10db on the volume control), the wife places her fingers on her temples. Hence creation of the "temple" standard. tongue.gif

(And why are they called "temples?")

-
I believe that 105db is at sustained levels of bass, but each channel should be able to peak up to 115db in the bass region. So in theory, all 7 channels could have peaks of 115db. If you bass manage (crossover) the bass of all of your channels to the sub(s), I believe the theoretical peak output for your subs go to 121db if all channels required that output at the same time.

So that would be the theoretical output of what your sub system should be able to reproduce for those brief dynamic peaks.

Someone correct me if I'm wrong...

That's how I understand it.
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post #29 of 58 Old 01-03-2013, 11:59 AM
 
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Quote:
Originally Posted by Stereodude View Post

Yes, but considering bass management and 7 channels at 105dB and a subwoofer at 115dB you get 117.3dB according to the dB calculator on this page.

Not arguing on any level. In response, I'm just posting the facts as I understand them. Room gain and bass management? That's a whole "nother" story. I'm just posting in regard to what the THX reference standard is and everything else is outside my pay grade.

THX calls for a speaker average of 85dB with headroom and an additional +10dB bump for the LFE channel dynamics plus additional headroom. My comments are intended to address the simple of it all as opposed to trying to address room gain, bass management and the synergism of seven highly efficient (+95dB/1W/1M sensitivity) speakers banging away in unison while coupled to a pair of bad boy fifteen or eighteen inch subwoofers with over 2,400 peak watts behind the two subwoofers.

(High smile factor, low WAF)

It took a long time for me to get my wife to understand that I don't have the volume turned up as it's the sound engineer who's turning the volume up during the action sequences. I showed her that in the warehouse scene, when being chased by the bad guys, the protagonists whisper and then bombs start going off everywhere and the increase in volume is called dynamics, but I personally haven't turned the volume up. I hate dynamic compression. I want the full dynamic range from whispers to explosions.

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post #30 of 58 Old 01-03-2013, 12:03 PM
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Quote:
Originally Posted by sputter1 View Post

That's how I understand it.
Except that's not how the math works. 105dB*7 + 115dB = 117.3dB, not 121dB.
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