# 'do-you-have-a-THX-subwoofer' AVR setting



## THX-UltraII (Nov 19, 2008)

THX certified AVRs commonly have a setting in the speaker/THX preferences that says 'Do you have a THX certified subwoofer' (question/setting can look different on various brands/model but this is what Onkyo calls it). I m looking for an answer what the difference is when putting it on YES or NO.

I AM NOT looking for an answer to put it on YES if one has a THX cert. subwoofer and NO if one does not, but I want to know the (detailed) discription what the setting does to the (subwoofer) sound/frequency or whatever else it does.

thanks!


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## The_Nephilim (Mar 3, 2010)

Well I dont have a detailed Explanation but Basically THX is just someone elses idea of what sounds good..

Some engineers from Lucas Arts, put together equipment that would meet a certain specification.. and if the Manufacturer of said equipment develops some AV Equipment they send it off the THX and then it goes through rigorous testing to get the certification..I am sure it is more detailed then some other specs like maybe better internals and such but you get the idea..

Basically it is like a Stamp of approval from THX..I am sure the THX stuff sounds great but hey most stuff does..I wouldnt say if it is NOT THX Certified that it is ..

IT is that these devices meeet the Stamp of Approval from some engineers at THX and companies pay money to have the THX Branded on their equipment..end result you pay more too.. I dont think the THX Stuff would sound any better or worse then comparable NON THX Stuff.. it just doesnt have that cool THX Logo on it..


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## rab-byte (Feb 1, 2011)

I may be wrong but I think the sub will need to have range from 120-20hz at +/-?db from some distance. I know THX crosses LFE over at 80hz but I'll bet it starts rolling off from the mains higher then that.


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## THX-UltraII (Nov 19, 2008)

The_Nephilim said:


> Well I dont have a detailed Explanation but Basically THX is just someone elses idea of what sounds good..
> 
> Some engineers from Lucas Arts, put together equipment that would meet a certain specification.. and if the Manufacturer of said equipment develops some AV Equipment they send it off the THX and then it goes through rigorous testing to get the certification..I am sure it is more detailed then some other specs like maybe better internals and such but you get the idea..
> 
> ...


I know what THX is and I know the history of it etc.
Read my post again: I want to know what the option does


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## The_Nephilim (Mar 3, 2010)

Well basically if you Read my post I said I do not have a Detailed explanation sorry for giving you a little backround..

But if you ask me THX is just snake oil and setting it to yes if you have a THX Certified sub probally does just set it at the speciied paramaters set by the THX Engineers..


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## Barleywater (Dec 11, 2011)

I believe you've got all the fundamentals down at this point for answering question yourself: 

The subjective approach is to listen to the two settings and come to opinion if they sound different, and in what ways.

And the analytical approach, for which you have extensive mentoring: Measure the difference. Remove all settings (store settings that you've been working on first). Connect sub output of AVR to soundcard, and make measurement for each setting, THX sub on, and THX sub off. Analyze results in REW. This will show you exactly behavior of THX setting.

Regards,

Andrew


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## Todd Anderson (Jul 24, 2009)

I think when you tell your AVR "yes" is automatically sets your crossover to 80hz, no?


As a side note, I drive a Lincoln navigator as a rental recently and the center dash had a big "THX Certified Audio" badge.

In no way shape or form was the car's audio system anything special, that's for sure.


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## THX-UltraII (Nov 19, 2008)

Barleywater said:


> Connect sub output of AVR to soundcard, and make measurement for each setting, THX sub on, and THX sub off. Analyze results in REW. This will show you exactly behavior of THX setting.


Very good suggestion. thxz


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## fokakis1 (Feb 29, 2012)

> I m looking for an answer what the difference is when putting it on YES or NO.


From my Onkyo owner's manual:

"If you’re using a THX-certified subwoofer, set the THX
Subwoofer setting to Yes. You can then apply THX’s
Boundary Gain Compensation (BGC) to compensate the
perceived exaggeration of low frequencies for listeners
sitting very close to a room boundary (i.e., wall)."

From what I've read, it has been stated that BGC applies an EQ that rolls off the low end.


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