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Discussion Starter · #1 ·
I need help narrowing down the Frequency range in which a null occurs with my SVS PB-13U, having no knowledge of how to use REW. (I suspect that I will need to find out how in order to fix the problem anyway.)


Three significant examples of the shortcoming are:


(1) The Bourne Ultimatum (HD DVD) -- The Moped Scooter Detonation: Absolutely no bass during the explosion until it cuts to Nicky (Julia Stiles), at which point a large amount of deep bass gives the room some after-shake.


(2) Iron Man (Blu-ray) -- (1:47:00) Iron Monger Launches a Rocket at a Bus, Blasting Iron Man into the Air: There is a complete lack of bass here from when the bus is hit all the way through Iron Man getting blasted into the air by the explosion. Tony getting hit with a motorcycle minutes prior is also missing any bass (he could have been hit with a feather for all I could tell
). The same effect, or lack there of, also occurs another few minutes earlier when Iron Man chest blasts Iron Monger to save a car full of kids (no bass accompanies the blast).


I found the Rocket hitting the bus timestamp in the Master Bass/Waterfall thread, but I had trouble interpreting what range was the culprit.


Again, the SVS PB-13 produces plenty of the deeper bass. Earlier in the film, there was plenty of bass accompanying the tank explosion, Iron Man's landing, and the Jet Chase. Iron Man going supersonic feels like an earthquake, and the subwoofer generates similar earthshaking results in scenes such as the revealing first shot of The Dark Knight.


(3) Vantage Point (Blu-ray) -- The First Explosion (and, for the most part, the subsequent versions of the same explosion): The initial explosion itself is completely lacking in any bass until the deep after-rumble bass sets in.


*(All three movies used their respective Dolby TrueHD audio tracks with Late Night manually Disabled. The PB-13's Room Compensation was set to Small.)*


I'm sure that this null impacts many more movies, but explosions that fall completely flat, unfortunately, really grab one's attention in the wrong sense.



In what bass frequency range does my problem seem to reside?



-----------


Other Setup Details:

-Room Dimensions: (W X L) 16' X 15' w/ Vaulted ceiling.

-Subwoofer Placement: 5' from the left corner and 1' from the back wall.

-Main Seating Position: A sofa with 1' between it and the back wall.

-Openings: (H X W) 6' 8" X 5' 2" opening into kitchen area located in the back right corner of the room.
 

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Maybe this was the director (or sound teams) intent for these scenes? I didn't know a null could be so large as to totally excise an entire range of LFE content so it would seem it was not there.



I have noticed this a bit too with certain films. For the big explosions you expect the matching audio component but it is not there, meanwhile in the same film, someone could turn their head in slow motion and the whole room is shaking.


I would listen to a bit more movies with explosions if you already haven't to see if it is just a product of sound design.


For what it's worth, I have been puzzled with Iron Man as well. It gets all these accolades for audio and people swear by it, but for me I feel a few scenes in it are anemic with the bass. Notably the end explosion and as you mentioned the fight in the street traffic.
 

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Discussion Starter · #3 ·

Quote:
Originally Posted by kirbybreezy /forum/post/16860184


Maybe this was the director (or sound teams) intent for these scenes? I didn't know a null could be so large as to totally excise an entire range of LFE content so it would seem it was not there.



I have noticed this a bit too with certain films. For the big explosions you expect the matching audio component but it is not there, meanwhile in the same film, someone could turn their head in slow motion and the whole room is shaking.


I would listen to a bit more movies with explosions if you already haven't to see if it is just a product of sound design.


For what it's worth, I have been puzzled with Iron Man as well. It gets all these accolades for audio and people swear by it, but for me I feel a few scenes in it are anemic with the bass. Notably the end explosion and as you mentioned the fight in the street traffic.

Thank you for your feedback.


I hope it is artistic intent, as I have been altering room compensation, moving the subwoofer, and re-calibrating with Audyssey MultiEQ XT many times due to these scenes.



I know that my setup currently has very little midbass impact, and a higher crossover of 100hz for my mains wasn't able to solve this. I temporarily placed my old JBL 12" sealed subwoofer in right near field and gained a great deal of midbass back, but it did nothing to aide the three scenes I noted above.
 

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It's hard to say exactly, but when you have dimentions that are multiples of one another, you have room modes that will wreak havoc with a desired flat or close to flat response.


The room mode calculators online can't really calculate for a vaulted ceiling but you have two dimentions close together, 15 x 16 feet. This is not great. Is one of the other dimentions on the vaulted ceiling 8 foot on one side?


The only real way to find out what you are experiencing is to measure the sub outside ground plane with RoomEQ wizard and then measure inside. Compare the two traces, and you can see what the room is doing.
 

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Discussion Starter · #5 ·

Quote:
Originally Posted by michael hurd /forum/post/16860354


It's hard to say exactly, but when you have dimentions that are multiples of one another, you have room modes that will wreak havoc with a desired flat or close to flat response.


The room mode calculators online can't really calculate for a vaulted ceiling but you have two dimentions close together, 15 x 16 feet. This is not great. Is one of the other dimentions on the vaulted ceiling 8 foot on one side?


The only real way to find out what you are experiencing is to measure the sub outside ground plane with RoomEQ wizard and then measure inside. Compare the two traces, and you can see what the room is doing.

Thanks for your feedback.


I'll have to measure the vault some other time.


With the great number of topics in which RoomEQ Wizard is recommended, I'm surprised that I couldn't find an official thread to help newcomers.


Is there a comprehensive link to a list of materials needed (I have an analog RS SPL Meter) and how to use the basic functions?
 

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are the dynamic range control / limiting things on your hi def players OFF? (they should be)
 

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Go to Amazon and check out Bass Mekanik and play the samples of various sweeps and bass freq tones until you've determined where your nulls are located. BTW, there are other free sweeps and tones you can get off the internet as well. If your nulls are that absolute, it should be easy for you to determine by ear which freqs are affected.
 

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Usually the problem with something is the easiest and most overlooked. So you have ran the auto setup, but have you checked the crossover on the actual sub? It sounds like the subs crossover is set low enough you are not getting the upper bass frequencies out of the sub. Turn the crossover on the sub up all the way and try running your setup again.
 

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Quote:
Originally Posted by AEguy /forum/post/16860396


Thanks for your feedback.


I'll have to measure the vault some other time.


With the great number of topics in which RoomEQ Wizard is recommended, I'm surprised that I couldn't find an official thread to help newcomers.


Is there a comprehensive link to a list of materials needed (I have an analog RS SPL Meter) and how to use the basic functions?

Home Theater Shack (where you probably got REW in the first place) has a great support thread for REW, it also has a great manual...
 

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Quote:
Originally Posted by AEguy /forum/post/16860396


Thanks for your feedback.


I'll have to measure the vault some other time.


With the great number of topics in which RoomEQ Wizard is recommended, I'm surprised that I couldn't find an official thread to help newcomers.


Is there a comprehensive link to a list of materials needed (I have an analog RS SPL Meter) and how to use the basic functions?
http://www.hometheatershack.com/forums/rew-forum/
 

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Quote:
Originally Posted by michael hurd /forum/post/16860354


It's hard to say exactly, but when you have dimentions that are multiples of one another, you have room modes that will wreak havoc with a desired flat or close to flat response.


The room mode calculators online can't really calculate for a vaulted ceiling but you have two dimentions close together, 15 x 16 feet. This is not great. Is one of the other dimentions on the vaulted ceiling 8 foot on one side?


The only real way to find out what you are experiencing is to measure the sub outside ground plane with RoomEQ wizard and then measure inside. Compare the two traces, and you can see what the room is doing.


I think Michael is right on all accounts. The nearly square room can certainly present problems. Make the effort to learn to use REW. It is the best way to find out what's going on. A more expensive, but much easier alternative would be the Velodyne SMS-1. It is a bass tweaker's delight.


The seating position near the back wall is also a problem. That makes for very strong bass at certain frequencies and strong nulls at others.


Michael is also correct about using the proper filter setting on the PB13 for the 15hz tune! It is there for a reason.
 

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Discussion Starter · #13 ·

Quote:
Originally Posted by ribbit /forum/post/16860487


are the dynamic range control / limiting things on your hi def players OFF? (they should be)

I bitstream the Lossless tracks to my Onkyo 805 and make sure to switch the TrueHD Late Night function 'Off' every time I play a different Dolby TrueHD track. My Panasonic BD-50 is in the Quality audio setting, cancelling out the pop-up menu sounds in favor of sending the main tracks to the Onkyo for decoding.

Quote:
Originally Posted by monomer /forum/post/16860859


Go to Amazon and check out Bass Mekanik and play the samples of various sweeps and bass freq tones until you've determined where your nulls are located. BTW, there are other free sweeps and tones you can get off the internet as well. If your nulls are that absolute, it should be easy for you to determine by ear which freqs are affected.

This is another process I knew I would eventually need to do, but I've always been hesitant, worrying I might damage the subwoofer with the tones. I will do it cautiously, as it should be done.

Quote:
Originally Posted by brandonnash /forum/post/16861037


Usually the problem with something is the easiest and most overlooked. So you have ran the auto setup, but have you checked the crossover on the actual sub? It sounds like the subs crossover is set low enough you are not getting the upper bass frequencies out of the sub. Turn the crossover on the sub up all the way and try running your setup again.

The PB-13U's crossover switches are all in the 'off' position and the PEQ frequency adjustments fully counter-clockwise. The crossover knob is turned fully clockwise to 120hz.

Quote:
Originally Posted by glaufman /forum/post/16861483


Home Theater Shack (where you probably got REW in the first place) has a great support thread for REW, it also has a great manual...

I didn't have REW in the first place.
Thank you.

Quote:
Originally Posted by AvGeek07 /forum/post/16861510


what scene chapter is that for iron,i never knew that and like to test that on my system. thanks

It's the last chapter before the end credits. For the Bus Rocket, proceed to 1:47:00.

Quote:
Originally Posted by penngray /forum/post/16861577

http://www.hometheatershack.com/forums/rew-forum/

Thank you for the direct link.

Quote:
Originally Posted by mojomike /forum/post/16861587


I think Michael is right on all accounts. The nearly square room can certainly present problems. Make the effort to learn to use REW. It is the best way to find out what's going on. A more expensive, but much easier alternative would be the Velodyne SMS-1. It is a bass tweaker's delight.


The seating position near the back wall is also a problem. That makes for very strong bass at certain frequencies and strong nulls at others.


Michael is also correct about using the proper filter setting on the PB13 for the 15hz tune! It is there for a reason.

I forgot to mention all my PB-13's settings in the original post, including that it is in 20hz tune.



I will be downloading and doing a lot of reading about and testing with RoomEQ Wizard.


Thank you to everyone who responded. While I don't know if the above mentioned scenes are artistic intent, I acknowledge the best way to make sure is to flattened out my PB-13's frequency response with the help of REW.
 

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Discussion Starter · #14 ·
Today was finally the day, and I was pleasantly surprised by the results. Now I know why IRON MAN going supersonic had so much bass.



The Attached measurements were taken by an Analog RS SPL Meter at my main seating position at ear height, which happens to be 16 inches from the rear wall of the room on the couch.


The Mains (JBL L820s -- in locations of which I am not fond) were set to crossover at 100Hz to my SVS PB-13 Ultra with room compensation off. Audyssey MultiEQ XT was also off.


Both measurements were conducted with '1M' 'Length' and '8' 'Sweeps' settings in RoomEQ Wizard for the best averaging results.


Between measurements 4 and 5, I had turned the receiver off and had to recalibrate the volume, causing a slight variance.


I'll be playing with the PB-13's parametric EQ to tame the 30Hz to 45Hz peak. I'm not sure what I will do about the 76Hz dip, but I will try lower crossovers and the phase knob.

 

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Cut that peak and it ain't bad. Still, I wouldn't think you'd miss much content with that FR.
 

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I don't think you are missing anything. I remember watching IronMan and commenting afterwards that there were scenes with absolutely no bass that should have had ample bass. My son thought the same thing. It's the film, not your room!
 

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It seems I remember some problems with Ironman and some processors, where the TruHD soundtrack triggered a filter in the processor/receiver. I think one of those affected was/is Integra 9.8. This is from memory. The Ironman thread in the BR forum should have the information.


Ron
 

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Discussion Starter · #18 ·
Thank you to all in this thread for helping me figure out that my worries are most likely artistic intent (Edit: My original post mentions manually turning off the Late Night mode during playback that many TrueHD tracks trigger) and for having me learn RoomEQ Wizard.


Here is a quick update on the 39Hz peak, which will be further corrected when I run MultiEQ XT in the next couple of days. The mains...need work.



Thanks again!



Crossover 100Hz:
 

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Quote:
Originally Posted by rboster /forum/post/16936445


It seems I remember some problems with Ironman and some processors, where the TruHD soundtrack triggered a filter in the processor/receiver. I think one of those affected was/is Integra 9.8. This is from memory. The Ironman thread in the BR forum should have the information.


Ron

I have the OnkyoPro 885, the equivalent of the Integra 9.8--I will have to go check that out
 

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Discussion Starter · #20 ·

Quote:
Originally Posted by Fatawan /forum/post/16936478


I have the OnkyoPro 885, the equivalent of the Integra 9.8--I will have to go check that out

If it's remote is similar to the Onkyo 805's, upon starting a movie with a TrueHD track, one should press the 'Late Night' button until the receiver indicates this feature is 'off.' The Iron Man Blu-ray and The Bourne Ultimatum HD DVD are both notorious for automatically triggering said feature, which is why I made a small note about manually checking this in my original post.
 
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