# Standing Wave control question - Q and ATT



## Guest (Sep 27, 2008)

Hello All,

Just signed up with the forum...actually just found this site! I have been an HT enthusiast for a few years and frequented most other sites and always happy to find another!

I tried posting this same question on another site and got no replies so I figure I would try here...

I have a Pioneer Elite receiver that has MCAAC (auto room setup)

One of the features is Standing Wave control. I have heard some people say that this feature should be turned off...any thoughts ?

My other question is when moving the speakers around, adding room treatments, and changing listening position - the Q value and ATT changes all the time. My question is, can you gauge the severity of the standing waves by the info provided on this screen? The Q values are rarely the same, but every once in a while all 3 frequencies will have a Q value of 9.8 (which seems to be the highest)....is this a good thing or bad thing ?

Thanks


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## thxgoon (Feb 23, 2007)

Well a quick google turned up no reliable explanation of what 'standing wave control' actually does. My guess is that it's a portion of MCACC that specifically looks for room related anamolies in the lower frequencies and applies eq to them. As for turning it off... try it both ways, whatever sounds best to you is always the correct setting :T

Standing waves are generated by room boundaries and are eliminated by acoustic treatment which can be anything from furniture to curtains. The Q (I'm assuming based on eq systems) adjusts how many frequencies around the center frequency are affected by the eq, while the ATT (I'm guessing this stands for attenuation) is the level of reduction in signal for that range of frequencies. The MCACC optomizes these setting depending on the reading it gets during the auto setup process so it would make sense that the values change when you move the mic or room treatments.

A good way to evaluated the severity of standing waves is to look at the level of correction being applied. Large correction impies large standing wave problems and vice versa. Hope that helps.


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## Guest (Sep 28, 2008)

Hey thanks for the info...

So... from your last sentence:

"A good way to evaluated the severity of standing waves is to look at the level of correction being applied. Large correction impies large standing wave problems and vice versa. Hope that helps"

... I take it when all three frequencies being adjusted have a Q of 9.8....that's a bad thing....


I play alot of first person shooters on the 360 and having rock solid imaging and nice soundstage are paramount to anything else in my theater room....Since I first got my new reciever I have been experimenting with speaker positions/distances/toe-in/angles....listening distance....surround heights...etc...etc...I have probably ran the MCAAC setup routine 500 times over the last year:dontknow: so seeing all 9.8's pop up on the MCAAC was like hitting all 777 on a slot machine...thought I found the magic spot in the room where the freq response was perfect....turns out just the opposite :unbelievable:

I have learned quite a bit and trial and error really applies...I was familiar with all the recommended starting points about equilateral triangles and monopole surrounds should be 90-110 degrees and 2-3 feet above ear level etc...turns out that the most immersive and SEAMLESS panning experience in my environment put the surrounds about 120-130 back degrees and slightly higher than ear level. I wish I would have tried this sooner! In the past all other experimentation was closer to the recomendation.

Anyways thanks for the info and I really like your room, looks dynamite! How much to build one of those subs? I was thinking of getting an HSU VFT-2 MK 3 but may DIY.


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## thxgoon (Feb 23, 2007)

dkolacz said:


> ... I take it when all three frequencies being adjusted have a Q of 9.8....that's a bad thing....


Honestly I don't know. It would depend on what your receiver is using to reference those number on. Q could also mean something much different as in this wiki article.



> Anyways thanks for the info and I really like your room, looks dynamite! How much to build one of those subs? I was thinking of getting an HSU VFT-2 MK 3 but may DIY.


Thanks! I built them for just under a thousand for both subs and the amp. IMO if you have the tim you can't go wrong with DIY. There's lots of help on this site too.


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