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Discussion Starter · #1 ·
I've calibrated all my speakers flat, including the subwoofer. I remember watching Star Wars: Episode II - Attack of the Clones in a movie theater and the bass during the spaceship flyover scene that ends in an explosion at the beginning of the movie was very strong. If I watch that scene on my calibrated setup at full reference level, I don't get that kind of bass during that scene. I have to bump up the subwoofer about 3-6 dB higher to get that same feeling.


This got me wondering if the movie theater had its bass hot or if reference level for movie theaters is different from that of home theaters.
 

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You probably felt the midbass from the mains at the movie theater as well as the 18's they use. A good movie theater has lots of 18's and 15's that go down to 20-25 Hz. Using memory is very hard to do especially that long ago. If you liked the movie theater sound then you can just turn up the sub. What are your settings and did you watch at reference? Just make sure, I know you already said you did.
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by mike2060 /forum/post/17003853


Increase your subwoofer gain then recalibrate.

Do you mean reduce the subwoofer channel trim on my A/V receiver and make up the difference by increasing the gain on the subwoofer? If so, I already have the subwoofer channel trim set on the lowest setting (-12 dB) and have adjusted the subwoofer gain accordingly.

Quote:
Originally Posted by MKtheater /forum/post/17003886


You probably felt the midbass from the mains at the movie theater as well as the 18's they use. A good movie theater has lots of 18's and 15's that go down to 20-25 Hz. Using memory is very hard to do especially that long ago. If you liked the movie theater sound then you can just turn up the sub. What are your settings and did you watch at reference? Just make sure, I know you already said you did.

Yes, full reference level.

Quote:
Originally Posted by MKtheater /forum/post/17003889


BTW, was your 115 db's peaks from just reading from a SPL meter or corrected thru a computer?

Read through the digital RadioShack SPL meter at listening position.
 

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I have that dvd, I will give it a try at reference level and let you know.


Just wondering during low dialogue parts are you down into the 60s?
 

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Nobody asked the OP what subwoofer he had.


Regarding the AoTC scene; it is and should be very loud in scenes like that. I get over 120db peaks.
 

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Discussion Starter · #9 ·

Quote:
Originally Posted by Jesse S /forum/post/17006083


Nobody asked the OP what subwoofer he had.


Regarding the AoTC scene; it is and should be very loud in scenes like that. I get over 120db peaks.

I have a SubMersive.


If you are getting over 120 dB peaks, I assume you've calibrated your subwoofer about 6 dB hot as the max peak is suppose to be 115 dB.


By the way, what are you using to measure your peaks?
 

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I run my mains small (as virtually everyone should). That directs more signal to the sub than just the LFE channel.


Dolby spec calls for peaks of 105db in *each* channel and 115 in the LFE. 5 channels of 105db peak + 115db is not 115db.


I use the rat shack analog meter for SPL measurements.


You mentioned you run your sub trim at lowest (-12). I think it's better to run the sub level at it's midpoint and then adjust the gain on the sub. The way you have it gives you no room to lower the sub level at the receiver. Also, the signal level may be a bit low going to the sub.


And why calibrate flat on the sub? Run it hot if that's what sounds good. Nobody ever said flat was correct for LFE. The dolby setup guide for mixing studios even calls for the sub to be run hot when the monitors (main channels) are run as "small".
 

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Quote:
Originally Posted by Kain /forum/post/17006103


I have a SubMersive.


If you are getting over 120 dB peaks, I assume you've calibrated your subwoofer about 6 dB hot as the max peak is suppose to be 115 dB.


By the way, what are you using to measure your peaks?


The Dolby spec for LFE results in a maximum peak level of 115 dB SPL if your subwoofer is calibrated flat.


The subwoofer output jack provides you with LFE plus redirected bass. The subwoofer output jack signal level with the subwoofer calibrated flat could give you maximum levels of near 121 dB SPL peak (115 dB LFE plus another 6 dB for redirected bass).


I measure my peak SPL level with a RS Digital SPL meter set to fast, MAX, C-Scale. I use the data hold function so the meter will record the peak over a long time period.
 

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Discussion Starter · #12 ·
For those using the analoge/digital RadioShack SPL meter: are you using any correction figures for the measurements taken from your SPL meter or are you simply relying on what the SPL meter says?
 

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Discussion Starter · #14 ·

Quote:
Originally Posted by MKtheater /forum/post/17006337


I just read from the analog meter. I agree with the other guys, turn the LFE trim up and use the gain on the sub(turn that down). What is your crossover at?

My crossover is set at 80Hz for all speakers.


As for turning the trim up and subwoofer gain down, there is a reason why I have the trim set at the lowest setting. When I first setup my subwoofer, I had the trim level on my A/V receiver set to 0 dB and the gain on the subwoofer set to -24 dB. At full reference level, it would cause the clip light on the back of the subwoofer to flicker a bit during the flyovers on Attack of the Clones and a lot of flicking during the explosion. Then I reduced the trim on my A/V receiver to the lowest setting (-12 dB) and increased the gain on the subwoofer to -10 dB. This resulted in the same SPL. However, this time, during the flyovers (at full reference level) the clip light did not flicker at all with only minor flickering during the explosion.
 

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It sounds like you have it right, you just need another sub. I still can't believe your speakers hit 120 db's at these frequencies, that is really good. I would run them small and cross them over as low as the processor allows(maybe 30 Hz).
 

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Lab tests by hi-fi magazines that do thorough reviews show that some AVR's distort the subwoofer signal when the sub trim is set to 0 or higher, thus many folks such as the SVS staff recommend setting your AVR sub trim about 25% of the way up from the bottom so you avoid potential signal distortion yet still have some room for conveniently tweaking the sub level on the fly if program material warrants it. So for example if your AVR sub trim has a range of +/-12, you would ideally set it at about -6 and adjust the gain control on your subwoofer itself during calibration with Avia or whatever pink noise tones you normally use to set speaker levels.


Cheers,

Ross
 

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Quote:
Originally Posted by MKtheater /forum/post/17006337


I just read from the analog meter. I agree with the other guys, turn the LFE trim up and use the gain on the sub(turn that down). What is your crossover at?

In another thread OP complained about his submersive clipping so I think he should make sure his gain is high enough as I believe someone else had the same problem which they fixed by increasing the gain on the sub.


Edit: I see OP fixed his clipping problem by doing this.


I would also advise OP to get REW and use his SPL to measure his frequency response in his room as some dips at certain frequencies can certainly take away some of that punch he wants.
 

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Wow, that disc had insane LFE.


I hit 120 slow weighted uncorrected



Wife told me to get her some qtips..it made her ears...itchy....



Felt like my whole body was being pummeled..


I found high output LFE throught out the movie... interspersed nicely..the ship noises among the loudest...
 

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Discussion Starter · #20 ·

Quote:
Originally Posted by theelviscerator /forum/post/17007356


Wow, that disc had insane LFE.


I hit 120 slow weighted uncorrected



Wife told me to get her some qtips..it made her ears...itchy....



Felt like my whole body was being pummeled..


I found high output LFE throught out the movie... interspersed nicely..the ship noises among the loudest...

What does your setup consist of? How have you calibrated your subwoofer(s)? Flat or hot? If hot, how hot? Are you using a RadioShack SPL meter?
 
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