Can Audyssey Overdrive Your Sub? - AVS Forum
Subwoofers, Bass, and Transducers > Can Audyssey Overdrive Your Sub?
wingnut4772's Avatar wingnut4772 11:01 AM 04-18-2012
Have read that Audyssey can boost nulls - a lot- a no no from what I am told. Will Audyssey boost enough to actually ruin a sub driver?

JDEaston's Avatar JDEaston 11:59 AM 04-18-2012
I'm not sure if it would ruin one but I have seen it drive a sub into distortion, in a scenario where there was no distortion at the same level before being eq'ed.

People put to much emphasis on room correction software and not enough on quality speakers and good placement. The problem with audyssey sub eq is that it can force the sub to try and produce a frequency that it may not be capable of replicating at high spl. This usually happens with cheaper subs. Ironically, the better, more expensive subs tend to have a flatter response curve and don't really need eq, however they may benefit from it some.

Personally rather than spending an extra 2-$300 on an avr that can eq the sub I would take that cash and put it towards a good sub with a flat response curve. But from reading these boards I can see that a lot of people won't even give an avr a second thought if it doesn't have the newest flavor of audyssey.
wingnut4772's Avatar wingnut4772 12:16 PM 04-18-2012
Thanks. I have good subs. Hsu ULS 15s.
ccotenj's Avatar ccotenj 12:22 PM 04-18-2012
any sub that is put in a room "needs" eq....

buying a "more expensive sub" will not change that in any material way...
JimP 12:24 PM 04-18-2012
Quote:
Originally Posted by JDEaston View Post

...snip...Ironically, the better, more expensive subs tend to have a flatter response curve and don't really need eq, however they may benefit from it some.


Not really.....unless you intend on using it outdoors all the time.

Anytime you bring a subwoofer indoors, you add in room interaction to the mix. You're equalizing mostly to correct for the room.

Some higher end subs need some eqing too.
ccotenj's Avatar ccotenj 12:28 PM 04-18-2012
^^^

yup...

i would go so far to say that you are eq'ing almost entirely for the room when you are eq'ing the subwoofer region... room modes rule the low octaves...

yes they do, as much as i wish they didn't...
JimP 12:30 PM 04-18-2012
While we're at it.......the sub always measure the best when its in some impossible position that you can't leave it there.

....and yes, I had a recent experience with that. lol
wingnut4772's Avatar wingnut4772 12:42 PM 04-18-2012
I also had a Velodyne SMS1 sub equalizer so I'm aware of the necessity of a good Sub EQ. Because of the room , I have a pretty decent 5 deb null in the 40 hz area which I usually just live with. No boosting but I think Audyssey boosts it.
JDEaston's Avatar JDEaston 12:50 PM 04-18-2012
Quote:
Originally Posted by JimP View Post


Not really.....unless you intend on using it outdoors all the time.

Anytime you bring a subwoofer indoors, you add in room interaction to the mix. You're equalizing mostly to correct for the room.

Some higher end subs need some eqing too.

The last part of what you quoted from my post is pretty much in line with what your repeating..

I stated that even subs with a flat response can benefit from eq, but in the grand scheme of things the quality of the sub along with room acoustics are more of a determining factor than the type of room correction your using. Even the best room eq software won't overcome poor quality and placement. In fact it can overdrive the sub and force it into distortion, which I think is what the original poster was asking..
ccotenj's Avatar ccotenj 01:06 PM 04-18-2012
Quote:
Originally Posted by JimP View Post

While we're at it.......the sub always measure the best when its in some impossible position that you can't leave it there.

....and yes, I had a recent experience with that. lol

story of my life...
ccotenj's Avatar ccotenj 01:15 PM 04-18-2012
Quote:
Originally Posted by JDEaston View Post

The last part of what you quoted from my post is pretty much in line with what your repeating..

I stated that even subs with a flat response can benefit from eq, but in the grand scheme of things the quality of the sub along with room acoustics are more of a determining factor than the type of room correction your using. Even the best room eq software won't overcome poor quality and placement. In fact it can overdrive the sub and force it into distortion, which I think is what the original poster was asking..

for eq, in the grand scheme of things, the only determinants are room acoustics, and how the positioning of the sub affects the excitation of the room modes...

it would have to be a REALLY bad sub for inconsistencies in it's usable frequency range to have much of an effect once it is in a room... and if it was that bad, you are wasting your time even attempting to eq it... because it's junk...
JackOften's Avatar JackOften 04:55 PM 04-18-2012
Quote:
Originally Posted by wingnut4772 View Post

Thanks. I have good subs. Hsu ULS 15s.

You can definitely overdrive ULS-15's with Audessey, especially with dynamic volume engaged. Nice thread on bottoming out with Audessey over at the Hsu forums. Yes, I was a victim with my dualdrive as Audessey figured out I could reach 15 Hz or lower and boosted that range a tad bit too much and would cause a knock in real low frequency scenes. No damage to my ULS's however.
the_abbot's Avatar the_abbot 05:14 PM 04-18-2012
Yes. Audyssey can overdrive subs. I had a problem with it overdriving my last sub. Dyn EQ caused bottoming out.
bsoko2's Avatar bsoko2 05:33 PM 04-18-2012
I don't like Audyssey.
kesando's Avatar kesando 05:48 PM 04-18-2012
Quote:
Originally Posted by JimP View Post

While we're at it.......the sub always measure the best when its in some impossible position that you can't leave it there.

....and yes, I had a recent experience with that. lol

I can attest to that. I was looking for a second spot in my apartment where 20-30 hz performance was best. It turned out that the spot was in front of my front door!

I cant imagine pushing a PB12plus out of the way everytime I left for work in the morning.
craig john's Avatar craig john 06:24 PM 04-18-2012
Quote:
Originally Posted by wingnut4772 View Post

Have read that Audyssey can boost nulls - a lot- a no no from what I am told. Will Audyssey boost enough to actually ruin a sub driver?

The phenomenon you describe is not Audyssey boosting nulls in the low frequencies. It is caused by the "volume normalization process" that Audyssey invokes. It is described here: http://www.avsforum.com/avs-vb/showt...2#post16972252 and explained here: http://www.avsforum.com/avs-vb/showt...2#post16982682

Quoting from those two posts:

Here is a graph that depicts what is going on:

Trace colours:
Red = Line level calibrated with Audyssey off to create a reference line for the following trace
Green = Line level with Audyssey on
Aqua = in room noise floor measurement
Blue = In room measurement with Audyssey off
Purple = In room measurement with Audyssey on


  • The green line, which represents the Audyssey filters, should be close to the inverse of the blue line, except here the green line represents the composite filters for all measurements fuzzy logic adjusted, whereas the blue line is the response at a single location.

  • The fact that the green line doesn't go horizontal until around 10 Hz suggests that Audyssey calculated the lower -3 dB roll-off in that very low range.

  • The fact that the green line crosses the reference red line at 60 Hz is result of normalization. Normalization adjusts the filter level up or down to set the area between the green and red lines above 60 Hz to the upper limit, equal to the area between the green and red lines below 60 Hz to the lower limit.

  • Prior to normalization the left-most portion of the green line sat on top of the red reference line.

  • Since the entire frequency spectrum per channel is not considered when normalizing the levels, the before and after Audyssey average SPL levels will not measure precisely equal, but nevertheless they will sound about the same level.

Craig
hometheatergeek's Avatar hometheatergeek 07:03 PM 04-18-2012
Hi wingnut4772, Pete and Dr. Hsu recommends that you set the ULF trim to the 50Hz setting....run Audyssey then after the auto cal is finished you can set the ULF trim back to 16Hz. It seems to help Audyssey from not boosting the low end as much.
kesando's Avatar kesando 05:52 AM 04-19-2012
Is it true that XT32 mostly fixes this problem?
Gov's Avatar Gov 06:07 AM 04-19-2012
Quote:
Originally Posted by bsoko2 View Post

I don't like Audyssey.

Audyssey XT32 is the "shiznitz"!!!
wingnut4772's Avatar wingnut4772 06:25 AM 04-19-2012
Quote:
Originally Posted by bsoko2 View Post

I don't like Audyssey.

Me either!
wingnut4772's Avatar wingnut4772 08:33 AM 04-19-2012
Quote:
Originally Posted by hometheatergeek View Post

Hi wingnut4772, Pete and Dr. Hsu recommends that you set the ULF trim to the 50Hz setting....run Audyssey then after the auto cal is finished you can set the ULF trim back to 16Hz. It seems to help Audyssey from not boosting the low end as much.

Thanks.
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