Setting distance SHORTER to align subs with the speakers?

Y

yepimonfire

Audioholic Samurai
I came across an interesting finding the other day when tweaking my subs. An audible suck out at around 50hz showed up in measurements, so I started tweaking the distance while measuring the spl at 50hz to see if that was the problem. Audyssey set the distance at 7.7', actual distance is 5.7', the distance I settled on the finally got rid of the null was 5' exactly. The crossover point (80hz) remained unaffected by the change.

Onto my question...

I've heard of having to set the distance further in order to align them properly, but shorter defies all logic to me. Any clue why that might be?

Sent from my LM-X210(G) using Tapatalk
 
TLS Guy

TLS Guy

Seriously, I have no life.
I came across an interesting finding the other day when tweaking my subs. An audible suck out at around 50hz showed up in measurements, so I started tweaking the distance while measuring the spl at 50hz to see if that was the problem. Audyssey set the distance at 7.7', actual distance is 5.7', the distance I settled on the finally got rid of the null was 5' exactly. The crossover point (80hz) remained unaffected by the change.

Onto my question...

I've heard of having to set the distance further in order to align them properly, but shorter defies all logic to me. Any clue why that might be?

Sent from my LM-X210(G) using Tapatalk
Interesting post. So Audyssey set the timing from the first arrival from the port and not the speaker. You have set the measured distance so the first arrival from the speakers is timed with the other speakers. Ported enclosures have this degraded transient response.

I would have thought that this is something Audyssey would have been able to sort out. But it is a really poor program so I'm not surprised.
 
mtrycrafts

mtrycrafts

Seriously, I have no life.
Interesting indeed. Did other frequencies get affected?
 
S

shadyJ

Speaker of the House
Staff member
Since the distance change needed to remove that null was so precise, what you did really was just move that null to another location. Yeah, you have moved that null out of that exact microphone location, but move the microphone a foot away in any other direction and the response gets wacky again. The only way to cure room modes below the transition frequencies is through a multiple sub system and maybe bass traps to a lesser extant. Audyssey is not a cure, and it is not a great solution to problems in bass frequencies unless you only listen with your head in a vice at a single location.
 
Y

yepimonfire

Audioholic Samurai
Since the distance change needed to remove that null was so precise, what you did really was just move that null to another location. Yeah, you have moved that null out of that exact microphone location, but move the microphone a foot away in any other direction and the response gets wacky again. The only way to cure room modes below the transition frequencies is through a multiple sub system and maybe bass traps to a lesser extant. Audyssey is not a cure, and it is not a great solution to problems in bass frequencies unless you only listen with your head in a vice at a single location.
I don't have nulls anywhere around the room now. This wasn't room related. If anything I have peaks at 50hz due to modal resonances as I near the boundaries, but no dips. Also not using audyssey for fr correction, just used it to set the levels.


Funnily enough, audyssey also screwed up the surround speaker distances, set one to 4.7' and the other to 4.1'.both are actually 4.3' exactly, and I made sure the mic was dead center.
Interesting indeed. Did other frequencies get affected?
Nope

Sent from my LM-X210(G) using Tapatalk
 

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