60hz is dead in my room. Help


I suggest doing the sub crawl and finding a better location in your room for your sub placement. That may very well solve your problems. After trying that you may want to consider buying a 2nd sub for more even bass response throughout the room across more listening positions. Finally, there is downloading REW and getting a mic so you can take measurements and then getting a minidsp so you EQ. 

My case might not have been as bad as yours, but I solved it by a combination of doing the subwoofer crawl & dual subs.

I've tried every spot on the room I can put a sub by doing the crawl. Where it is is the best spot everywhere else. Every spot I've tried 60 hz is dead right down the middle. I use to have a velodyne SMS-1 I think it's called but nothing helped it at 60. I'm using multeq xt32 and it's got it sounding great but nothing can fix the 60 hz with EQ or placement. I think I need to go treatment but I have no idea how or where to place it. It's very confusing.


It's bad enough I was playing a 60hz tone and it was at 95db and I would move the meter 2 feet to the spot and it dropped to 68. I muted the sound and the Meter didn't change it stayed at 68. It's like witchcraft.


I'm also not sure a second sub would help since placement doesn't effect it. Plus I can't afford another svs pb 13 ultra. I was hoping one of them would be enough.


Is there a way to test where treatment would help the most to get rid of a problem like this?


^ that's something I have no idea about. Hopefully somebody will chime in with some help though. 



Quote:
Originally Posted by bevofrancis  /t/1517372/60hz-is-dead-in-my-room-help#post_24345451


I've been fighting a terrible dead spot all the way down the center of my room length wise. Its from the ground to about 3 1/2 feet high from one end if the room to the other right down the center and it's about 3 feet wide. There is literally no sound at 60hz. It could be 100db and you move your head 2 feet and it's completely gone.


My room is 24 x 13 with 8 foot ceilings.


What are my options to try and cure this. There really is no way I can set the room up that doesn't put me in this dead zone one way or another without me sitting also right against the wall.


Treatments? Spots to put it first?


Any help would be great. Ask any questions you like and I'll try and answer in as much detail as I can.

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It is normal for the center of the room to behave badly. It is recommended that you never place your seating at the 1/2 way points in a room.


What do you have for programs to measure the FR of the speakers in the room?

Reads like you badly need a second sub on the opposite wall.


My understanding, when two waves of the same frequency run into each other (reflections) they cancel each other out, creating a null in the process.


This can be cured by adding an equal second sub and placing it on the opposite wall.



Quote:
Originally Posted by J_Palmer_Cass  /t/1517372/60hz-is-dead-in-my-room-help#post_24345646


It is normal for the center of the room to behave badly. It is recommended that you never place your seating at the 1/2 way points in a room.


What do you have for programs to measure the FR of the speakers in the room?

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I'm sitting in the middle of the width but in the front 1/4 of the room. All I have to measure with is my ears and a radio shack spl meter.

Depending on how badly that null bothers you, you could just get another sub which covers that frequency. You don't have to buy another PB13 just to take care of 60 Hz null, you might look at a Hsu MBM-12 which was designed to tackle issues exactly like this. The Premiere Acoustics PA-150 also has huge 60 Hz output, but it may not be quite as tight, plus it has quite a bit more distortion for the same loudness levels as the PB13, so it doesn't match up as well.

Another way to look at it, does anybody sit in the null while watching movies? Just saying, if not, who cares? The point, sound management is about the listening positions and not the part of the room where nobody cares.


(trying to be encouraging here)



Quote:
Originally Posted by bevofrancis  /t/1517372/60hz-is-dead-in-my-room-help#post_24345741


All I have to measure with is my ears and a radio shack spl meter.

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You'll never get it right without measurement software, and you'll never get it right with just one sub. The reason is that what gives you the best result broadband results in that 60Hz null, so you need a second sub placed to that its maximum output at the LP is at 60Hz to fill the hole. Finding the right spot is a hit or miss proposition without measuring gear.



Quote:
Originally Posted by Bill Fitzmaurice  /t/1517372/60hz-is-dead-in-my-room-help#post_24346881


You'll never get it right without measurement software, and you'll never get it right with just one sub. The reason is that what gives you the best result broadband results in that 60Hz null, so you need a second sub placed to that its maximum output at the LP is at 60Hz to fill the hole. Finding the right spot is a hit or miss proposition without measuring gear.

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I'll try and use the software this weekend. I've got a friend that had a pb 12 plus sub. Maybe I can talk him into upgrading and selling me his.

Dual subs, a microphone, and software .... It is the only sane way to deal with this problem. Personally I had a great deal of benefit simply moving my seating position back about 6". The other comments are right... the middle of the room sucks (literally).


Room treatments are unlikely to kill a null of the magnitude you are talking about. I have plenty of room treatment and still have certain nulls.

I would bet at least 95% of guests in home theaters could care less about the exact acoustics of the room and would not even notice or listen critically.


This is certainly the case with my crowd who might plop themselves on the side or corner of the room or whatever...


I would suggest optimizing the owner's position above all other considerations since that is likely who will be using the home theater for any "critical" listening.


If the rest of you guys have a group of audiophile buddies then you are either really lucky to have a group of friends that share your interests... Or you and your friends are all nerds... Or both!



Quote:
Originally Posted by bevofrancis  /t/1517372/60hz-is-dead-in-my-room-help#post_24345451


Spots to put it first?

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Can you try putting the sub in the null (midpoint of room width)?



Quote:
Originally Posted by sdurani  /t/1517372/60hz-is-dead-in-my-room-help#post_24355618


Can you try putting the sub in the null (midpoint of room width)?

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Wont this just lead to another null elsewhere? I would guess you still need another sub at least