AVIA Note: Subwoofer Calibration (1 Viewer)

[CameronS]

If a speaker is set to "large" its low bass content will not be sent to the subwoofer output. Remember this!

Not sure why, but when my Sony 30ES receiver's speaker settings are set to "Large", the very low bass is still sent to the subwoofer.
"Soundfield Off" sends no bass from the mains to the sub.
I leave my mains set to Large because the Small setting routes too much high frequency bass to my sub.
I could be wrong, but I think the settings of "small" and "large" only change the crossover frequency on some older Sony receivers.
Owners of either the Sony 50ES or 30ES please feel free to chime in!
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The HTF Lowest Post Champion!
[Edited last by Cameron Seaman on September 10, 2001 at 10:50 PM]

 

[Guy Kuo]

Could well be true. Not all receivers have identical bass management. At least you can tell what is actually happening with the tones.
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Guy Kuo
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Ovation Software, the Home of AVIA DVD

 

[John Cain]

Terrific info folks..

- John

 

[Gregg Loewen]

Another thread worthy of putting in the Archieves
Guy, when is the need Avia coming out??
Gregg

 

[Lou Sytsma]

Excellent post Guy!

Is there any rule of thumb as far as phase settings go?

For instance having your sub in a corner behind your main speakers - chances are they will be in phase. OTH if your sub is along a sidewall halfway down the room it would be 90 degrees out of phase and at the other end of the room the sub would be 180 degrees out of phase.

These examples are a gross oversimplification I realize. Or does the environment of one's HT room play a bigger role in phase settings?

 

[Guy Kuo]

So far as phase, if the system has the subwoofer and speaker distances (or delays) correctly set in the receiver, the phase of the subwoofer will usually be normal. However, it is best to test using the subwoofer phase tests in AVIA to verify and adjust phase.

The instructions suggest having an assistant adjust the sub phase while you sit at the primary listening position. The phase position which yields the least cancellation between the main speaker and sub is the one desired. If you don't have an assistant, it is reasonable to use an SPL meter mounted at the listening position and adjust phase to achieve the highest reading. If you have a sub which only has two phases 0 and 180 degrees and the two positions yield identical results, the sub may possibly be at 90 degrees phase and it wouldn't matter which position you leave phase. It is possible to fine shift phase using the subwoofer distance control but that would require some experimentation.

 

[Jerry Gracia]

Excellent stuff!

It's threads like these that make visiting this site worth the while.

 

[DaveLenhert]

Exellent info Guy!!

However one question remains...

Why is it necessary to pre-compensated the LFE by -10 dB? Is it simply a result of all recievers base management boosting the signal by 10db or is it that most DVDs boost the LFE by 10db?

thanks

dbl

 

[Kevin C Brown]

Guy- I think that I know, and you even had this in your 1st post, that the very process of crossing over between the sub and mains, can induce a phase variance.
And also, using an EQ. (I.e., *any* filtering whatsoever, can change phase.)
For example, I have measured the distance to my mains and sub meticulously, yet I still have to put in a -120 degree phase adjustment on my sub to get it in phase with my mains. (180 out + 60 in.)
(I have done the one-person, squinting-eye method of adjusting the continuously variable phase knob on my sub while looking at the SPL meter at my listening position.)
My sub is in the corner, behind my left main speaker. I use all "small" with an 80 Hz crossover to all my speakers. And I'm also using a BFD.
Great info and post! I for one, really appreciate your presence on this forum!

 

[John Cain]

This one really needs to stay near the top..

Fantastic info here..

-- John

 

[Guy Kuo]

Thanks, John. It is heartening to see info in a thread being used. Every once in a while one feels like the really good and info juicy posts that take a long time to write end up garnering very little attention. You watch them scroll of into oblivion with nary a response and wonder why you took the time to write. It's ones like this that give the occasional impetus to stay on the forums.

As to why the LFE test signal needs the -10 dB recorded level.... It is because the receivers are supposed to boost the LFE by 10 dB automatically on playback. This allows the LFE track to have a greater dynamic range. It is part of the system design and your receiver should do that unless you go into the menus and intentionally set the LFE to -10 dB (10 dB softer than normal). So in order for an LFE test signal to play back at the same SPL as a test signal on the main channels, you have to record it 10 dB softer.

 

[Christian Speights]

I love you guys!

I have been running my speakers at "Large" and calibrated accordingly. Looks like I have some tweaking to do this weekend.

Great stuff! Thanks.

 

[Dennis B]

Guy,

Great post. AVIA was well worth the wait.

Thanks,

Dennis

 

[Sonnie Parker]

Guy,

We highly recommend setting all speakers to "small"

I'm trying to understand this with my setup. I use the Sony TA-E9000ES and if I set my mains to "small" the lowest x-over point I can set is 99hz for the mains. This means my x-over point on my sub will be very high. Of what I can gather from many a fine post is that the x-over on the sub should be set to 40-50hz if possible. If I did this I'd have a gap between that 40-50hz and the 99hz. In this case I don't believe the "small" setting would work for my mains.

Maybe Sony will upgrade that option as they did for the LFE x-over points.

SP

 

[Kevin C Brown]

Sonnie...

I use the Sony TA-E9000ES and if I set my mains to "small" the lowest x-over point I can set is 99hz for the mains.

Incorrect. The TA-E9000ES can go as low as 40 Hz (and maybe even lower, I never checked. I have used 80 and 60 Hz before on this pre/pro). Do you have the latest software? You should try to get a hold of at least 1.18c. 2.01 is the latest released in the states, and 2.5 has been released in Japan. Check out the following for more info...
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[Bruce N]

Sonnie, I agree with Kevin. I have a TA-E9000ES and it definitely has adjustable crossovers for main, center and rear that can be set as low as 40Hz in 10Hz increments.

That being said, I still think the 80Hz crossover point is best for my Definitive BP30s.

Bruce

 

[Sonnie Parker]

Sorry fellows,
I was getting the EQ section of the Sony confused with the x-over section. (The lowest frequency you can adjust is 99hz-unless I'm still confused.) You are right....my upgrade to the 2.01 version does allow x-over down to 40 hz now. Duh me!
Btw, this has got to be one of the best post in the forum. Thanks Guy!
What a salesman! I had to go and buy the AVIA DVD.
SP

 

[Bob_M]

Hi Guy,

How will Avia compare to the new HOME THEATER TUNE-UP disk you did for S&V.

Thanks Bob

 

[Kevin C Brown]

Bruce N: A man after my own heart!
I use 80 Hz for BP-30s too. Although we could probably get away with 60... (I use 80 for all of mine.)

 

[Barry Barnes]

Am I correct that the AVIA discs' lowest frequency sweep is at 20 Hz? My Sub is still going strong at 20 but that's as low as the test disc seems to go. Are there deeper test tones in there somewhere that I'm missing?