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"Official" Audyssey thread (FAQ in post #51779) - Page 2065

post #61921 of 70887
Quote:
Originally Posted by mogorf View Post

Quote:
Originally Posted by batpig View Post

Audyssey will almost certainly give you the runaround and deny that their technology could damage the sub by boosting it below its capabilities. During the measurement they calculate the lower limit (F3) of the sub and the filters taper off below that point to avoid boosting the sub below its lower limit. However, the subwoofer can still be boosted below this frequency due to the "normalization" problem that has been amply discussed in this thread (also something else which Feri will deny exists despite the large body of evidence).

Well, on a slow Tuesday here's some seed for thought I'm throwing in for further discussions:

A recent Q&A I had with Chris K. on the subject:

Q: Hi Chris et al,
I still occasionally come across forum threads where people claim Audyssey boosts low frequencies below the measured -3dB point of their subs and are worried about a possible damage. Some even show graphs taken off the pre-outs of their AVR’s sub-output as evidence showing huge boosts below 10-15 Hz even going down to 2 Hz. Others claim that the issue has been solved in newer AVRs and that is a problem of the past. While some think it’s related to normalization issues Audyssey implements as a final stage of auto-setup thus having such a hiccup at the very low end of the spectrum. Chris, is there any way to put an end to this “urban” legend” or there is something behind in the technology that you could share with us for better understanding? Thank you in advance as always.

A: I've seen these as well. MultEQ (all versions) is limited to a 9 dB maximum boost. Nothing more than that is possible. In the very early versions (many years ago) it was just left to do that and the natural roll off of the speaker that was much steeper would prevent any over boosting. In later versions there is a tapering method applied to stop the boost gradually as you go below the roll off point.

Calling all experts to chime in for further discussions, no "Chris is biased " comments please. smile.gif Also awaiting members to the discussion who had such issues that they have finally and permanently solved with explanation on how they solved it. smile.gif

 

Chris says the boost is maxed at 9dB. That's 8 times more amp power.  IMO he doesn’t answer the question. Boosting by 9dB below the F3 could certainly cause problems for many subs, as has been reported here time and again. Chris dodges the issue of normalisation causing the problem and offers no comment at all on that. I don't think it's an issue of Chris being 'biased' - he is doing what he always does - answering the part of the question that suits him and ignoring the part that doesn’t. I am not criticising him for this - he works under commercial restrictions - but it does mean that his answers are often less than useful IMO, especially when the question is linked to the 'secret sauce' as it is here.

 

Perhaps you'd care to go back to Chris and ask him to comment specifically on normalisation and how that might cause excessive boosts to be applied in, for example, a circumstance where a huge peak has been tamed, thus removing so much energy that a normalising boost has to be applied to 'normalise' the response in dB terms.  By 'normalising' in this way, it is entirely possible that the overall boost applied is too great for the sub in question to handle cleanly.  Ask Chris to specifically comment on normalisation and let's see what he says...


Edited by kbarnes701 - 5/8/13 at 3:12am
post #61922 of 70887
Quote:
Originally Posted by mogorf View Post

Quote:
Originally Posted by batpig View Post

Just look at this graph. It's not an "urban legend", it's a direct measurement. How do YOU explain this graph then?

Hi bp, it's not that I'd like to explain that graph, but on the contrary can you post some posts where people have reported that their subs were really damaged because of this issue? eek.gifcool.gif

 

Ooooh - you are wriggling there for sure, Feri! :)  Let's first try to agree that the graph is an accurate representation of what is happening, which means that Audyssey can, and does, boost excessively below the F3. It seems from your wriggle that you realise that is possible and that you cannot deny the objective evidence before your eyes.

 

So are you now in agreement with us that Audyssey can, and does, sometimes apply excessive boost due to normalisation?  Good.

 

Now, your next question was "can you provide some evidence of where subs were actually damaged?".  And I say, does it matter?  The point is that it is not clever to overdrive the sub way beyond its rated performance envelope. Would you want to try this out with your own sub?  I know I wouldn't. Your latest position seems to be "OK, you have shown me that it is indeed possible to drive a HB pencil deep into the human brain - but do you have any evidence at all that someone has done this with a real HB pencil and that it caused them harm?" Does the lack of that evidence negate the earlier evidence?

post #61923 of 70887
Quote:
Originally Posted by mogorf View Post

Quote:
Originally Posted by batpig View Post

Just look at this graph. It's not an "urban legend", it's a direct measurement. How do YOU explain this graph then?

Hi bp, it's not that I'd like to explain that graph, but on the contrary can you post some posts where people have reported that their subs were really damaged because of this issue? eek.gifcool.gif

 

But can you explain that graph, if normalisation is not causing the self-evident boost. What is your explanation?

post #61924 of 70887
Quote:
Originally Posted by mo949 View Post

Batpig, I'll try it when I mess with my room with the high pass.

Morgorf, you've proven to be a bit slow, arrogant, and one sided so its hard to take your suggestions seriously even if you happen to be right and the solution is to put the subwoofer where my coffee table normally sits - its room correction software and I've followed all the setup guidelines so my setup is within spec, even the audyssey employee recognizes this and doesn't ask me to move the subwoofer all around the living room. You've also never answered my question on why you wanted the transcript of my audyssey conversation and the person I spoke to, but maybe that's just your reading skills...

 

You have to remember that for Feri, Audyssey is akin to religion :)  I wouldn’t dismiss his suggestion though. I am fairly sure that you are experiencing a genuine problem and that Audyssey is the cause of it. However, based on the potential explanations offered in the thread, it would, IMO, be worthwhile to move the sub to a different location, even if you cannot keep it there permanently, just to prove or disprove if it is the 'normalisation theory' that is your problem. If the sub's position is causing a large boost at a certain frequency, it is possible that Audyssey is applying a lot of cut to that boost and then it has to raise the average overall dB level to compensate. That would give the effect you are experiencing, and also explain why it goes away when you turn Audyssey off.

 

I appreciate you have followed all the setup guidelines, but it's important to remember that Audyssey cannot work magic. There may be various combinations of equipment, rooms and placement that catch Audyssey out sometimes and yours may be one of them. Temporarily relocating the sub will verify it one way or another, and if the problem goes away when the sub is in a different place, it may help you to achieve a permanent solution. Sometimes moving a sub by a few inches can make a difference, and that my be feasible in your domestic situation without causing too much WAF grief.  Just a thought...

post #61925 of 70887
Quote:
Originally Posted by mo949 View Post

So, is 3 1/2 feet to the side of a corner and 3" from the wall, still considered 'corner placement'? I can get closer to the corner, but not further away than that.

 

Is that the current location or the suggested new location for the purpose of the test? 

 

You might also consider putting the sub in a totally different spot just for experimental purposes. I think that at this stage we are not trying to suggest a permanent, good spot for the sub, but rather trying to establish if the sub's location is causing the problem. 

post #61926 of 70887
Quote:
Originally Posted by mogorf View Post

 You bet Keith will stay alert and will add the resolution to the FAQ he is so excellently taking care of.

 

I haven't forgotten - I am waiting to see if there is a resolution to this particular case before drafting a FAQ answer, but one on potential normalisation issues will certainly be forthcoming...

post #61927 of 70887
Quote:
Originally Posted by D Bone View Post

Hey batpig, can you explain to me what you mean by "it's the normalization of the subwoofer channel after equalization"?

Thanks in advance!

 

Not batpig, but my last few posts in this thread possibly explain that in more detail. Briefly, how Audyssey works is that it listens to the FR in the room and tries to achieve a flat response (well flat as defined by Audyssey's target curve) by applying boosts and cuts where it encounters dips and peaks. If there is a particularly huge peak, or peaks, somewhere in the lower end of the frequency range, Audyssey might make big cuts in order to flatten the response. But those cuts might be so big that they remove sufficient energy that the overall dB level in that region is now lower than it should be. So to bring it back up to where it should be, Audyssey applies 'normalisation', which means it boosts the dB level. It is this boost that is controversial and the cause of speculation that it can result in the subwoofer being asked to play louder than it is designed to, at those frequencies in question. This could overdrive the sub and potentially damage it.

 

The reason Chris's answer to Feri's question is not helpful is that Chris only comments on the dB boost/cut that Audyssey applies during the actual equalisation. IOW, Audyssey can only boost by 9dB max when it is trying to deliver the flat frequency response just mentioned above. But that is not what we want to know - as batpig points out to Feri, what we are concerned with in this particular discussion is the normalisation boost, which is applied after EQ

 

HTH.

post #61928 of 70887
Quote:
Originally Posted by ezrangel View Post

Hello guys, i need an opinion.
I started building a new room in my new apartment. It's gonna be a small room: 540 x 282 cm, (sorry, I cant think in imperial units!). It's not high either, maybe 260 cm. I was looking for solutions on how to escape from the sensation of a small theater room. I found out that Audyssey DSX, with height and wide channels, can cause the feeling of an expanded room! I have been reading a lot on Audyssey site and a lot of recomendations from Chris Kyriakakis, mostly saying how importante wide channels are, and like they should be close to 60 degree angle to the center.
Well, here goes my problem...
As the room is almost twice lengh as it is wide, the front channels are not going to be 30 degrees from the center (60 from each other) as recomended, but only 18 degrees. And the wide channels might be at a 60 degree angle, but they will be very close to the listening position and sorround speakers.
The room was supposed to be, inicially, a 7.1 room. The surrounds and surround back are dipolar. I'll show you a diagram for you to see how close the wides are gonna be to the LP and surround. Sorry for the bad scan!


A and B are the places where the wide channel speakers are supposed to be!

Theorically, it should work... any thoughts?

Thank you very much for any assistance!

 

 

In Imperial the room is about 17.5 feet by 9 feet. My first comment is that you are probably sitting too far away from the screen. Here is a useful viewing distance calculator:

 

http://myhometheater.homestead.com/viewingdistancecalculator.html

 

What size screen will you be using?  I'd use the calculator to establish the best distance from the screen for your main viewing position and then make the diagram again, showing the angles that now result from the new seating position. 

 

Can you also tell us if you will be applying acoustic treatments to the room and whether it will be used just for movies or if you will also be listening to 2ch music there as well?

 

If you treat the room well, it can 'disappear' more or less completely and the physical size will no longer be too much of an issue. FWIW, your room is quite a bit bigger than my own, and my room sounds incredibly spacious, when required by the movie content to do so (eg a scene in a large aircraft hangar). It also sounds very small and claustrophobic when required to by the movie content (eg a scene in a small interrogation room).  The result of the treatment is that the walls just 'disappear'.

post #61929 of 70887
Quote:
Originally Posted by sdurani View Post

Your wide speakers, side speakers and rear speakers seem all bunched together. Without any meaningful separation they'll become a blurry mess.

How much are you willing to move your seating and speakers?
That is the main problem, the back of the room has a lot of speakers together.
Maybe I can move the couch 4 inches to the front, but that´s it! How would you recommend moving the speakers?
Quote:
Originally Posted by kbarnes701 View Post


In Imperial the room is about 17.5 feet by 9 feet. My first comment is that you are probably sitting too far away from the screen. Here is a useful viewing distance calculator:

http://myhometheater.homestead.com/viewingdistancecalculator.html

What size screen will you be using?  I'd use the calculator to establish the best distance from the screen for your main viewing position and then make the diagram again, showing the angles that now result from the new seating position. 

Can you also tell us if you will be applying acoustic treatments to the room and whether it will be used just for movies or if you will also be listening to 2ch music there as well?

If you treat the room well, it can 'disappear' more or less completely and the physical size will no longer be too much of an issue. FWIW, your room is quite a bit bigger than my own, and my room sounds incredibly spacious, when required by the movie content to do so (eg a scene in a large aircraft hangar). It also sounds very small and claustrophobic when required to by the movie content (eg a scene in a small interrogation room).  The result of the treatment is that the walls just 'disappear'.
My screen is going to be 106¨ 2.4:1 (250 x 104 com). It´s within THX and SMPTE recommendations. But yes, by the calculator, I could move closer.
The room wil be used for movies in 70% of time and 2ch stereo for about 30%.The stereo sound is important for me.
Yes, I intent to do some acoustic treatment, but still dont know what. If you have any comments on that, I would be pleased!
post #61930 of 70887
I think this clears up a good bit in a discussion in another thread here at AVS.
post #61931 of 70887
Quote:
Originally Posted by ezrangel View Post


That is the main problem, the back of the room has a lot of speakers together.
Maybe I can move the couch 4 inches to the front, but that´s it! How would you recommend moving the speakers?
 

 

Keep in mind that as you move the listening position forward, the effective angle with the front left and right speakers increases as well.  So you have a trade-off between being too close to such a large screen, and good sound imaging (for both movies and music).

 

If I were doing it, I would move the listening position forward until the stereo imaging for the front speakers was improved, which would also improve the rear surrounds (since they would be further away).  Then I would place the Wides closer to the front of the room, looking for the best compromise between the 60-degree Audyssey recommendation (which you are not likely to be able to achieve) and the best sound.  Once the sound is optimized for your room, I would consider right-sizing the screen, based on how far away the listening position is.  Sitting closer to a smaller screen is roughly equivalent to sitting further away from a big screen.

post #61932 of 70887
ezrangel,

Here's the placement guide for the wide speakers from Audyssey that might work better in your setup;

"The ideal location for the Wide speakers is along the side walls at 60° out from the center channel. To find the right spot, measure the distance from the center speaker to the left speaker. Then double it. That's where the Left Wide speaker should be placed. Repeat for the right side. The idea is to separate the Wides from the main left and right speakers so that their content is clearly coming from a different (wider) direction."

http://www.audyssey.com/blog/2010/05/a-practical-guide-to-audyssey-dsx
post #61933 of 70887
Patrick, the OP's left and right speakers are practically against the side walls, so it would be difficult to accomplish what the guideline recommends.
post #61934 of 70887
Quote:
Originally Posted by kbarnes701 View Post

Not batpig, but my last few posts in this thread possibly explain that in more detail. Briefly, how Audyssey works is that it listens to the FR in the room and tries to achieve a flat response (well flat as defined by Audyssey's target curve) by applying boosts and cuts where it encounters dips and peaks. If there is a particularly huge peak, or peaks, somewhere in the lower end of the frequency range, Audyssey might make big cuts in order to flatten the response. But those cuts might be so big that they remove sufficient energy that the overall dB level in that region is now lower than it should be. So to bring it back up to where it should be, Audyssey applies 'normalisation', which means it boosts the dB level. It is this boost that is controversial and the cause of speculation that it can result in the subwoofer being asked to play louder than it is designed to, at those frequencies in question. This could overdrive the sub and potentially damage it.

The reason Chris's answer to Feri's question is not helpful is that Chris only comments on the dB boost/cut that Audyssey applies during the actual equalisation. IOW, Audyssey can only boost by 9dB max when it is trying to deliver the flat frequency response just mentioned above. But that is not what we want to know - as batpig points out to Feri, what we are concerned with in this particular discussion is the normalisation boost, which is applied after EQ

HTH.

Got it! Thanks for the time to respond. smile.gif
post #61935 of 70887
And just to be clear, this "issue" is not something that you should ever really worry about. IF it is real (and it's still not conclusive that it is) it's extremely rare, triggered by some unusual combination of circumstances (room acoustics, subwoofer position, etc).

I say this just because I want to head off any spiral from "lurkers" suddenly growing worried about potential damage to their systems. I know how internet forms work, somebody mentions some obscure problem and then the paranoia spreads smile.gif
post #61936 of 70887
Quote:
Originally Posted by ezrangel View Post

Maybe I can move the couch 4 inches to the front, but that´s it!
Well, that's not going to help. I was going to suggest something more radical, like moving the seating a couple meters forward.
Quote:
Originally Posted by ezrangel View Post

How would you recommend moving the speakers?
If you blow across an empty Coke bottle, you can get that small chamber to resonate. Enlarge that space to your 540x282 cm room, and that chamber will still resonate (produce strong peaks & dips at certain frequencies). For your room width, those frequencies will be at 61Hz, 122Hz, 183Hz, 244Hz and 305Hz. You can eliminate the first one by placing your subwoofer at the middle of room width, either on the front wall and/or middle of the back wall (if you have a 2nd sub). The rest of those width resonances can be cancelled by spreading your front L/R speakers 188cm apart. This will give you smoother sound across your entire seating.

The problem with having your speakers only 188cm apart is that you could end up with a really pinched soundstage. The way to avoid that is by moving your seating forward and/or moving the speakers towards the seats. For example: you currently have a tiny 36° soundstage; moving 2.25m from the speaker plane would give you a 45° soundstage and moving 2m from the speakers would result in a 50° soundstage. You can see where I'm going with this: if you want anything close to the speaker angles that Audyssey recommends, your entire set-up would occupy only the front half of your room. That would give you much more consistent spacing between your fronts, wides, sides and rears. Currently you have your fronts far away from you and the rest of the speaker pairs clustered around your seating, with a big open gap in between.
post #61937 of 70887
Quote:
Originally Posted by batpig View Post

And just to be clear, this "issue" is not something that you should ever really worry about. IF it is real (and it's still not conclusive that it is) it's extremely rare, triggered by some unusual combination of circumstances (room acoustics, subwoofer position, etc).

I say this just because I want to head off any spiral from "lurkers" suddenly growing worried about potential damage to their systems. I know how internet forms work, somebody mentions some obscure problem and then the paranoia spreads smile.gif

+1. smile.gifcool.gif
post #61938 of 70887
Quote:
Originally Posted by kbarnes701 View Post

The reason Chris's answer to Feri's question is not helpful is that Chris only comments on the dB boost/cut that Audyssey applies during the actual equalisation. IOW, Audyssey can only boost by 9dB max when it is trying to deliver the flat frequency response just mentioned above. But that is not what we want to know - as batpig points out to Feri, what we are concerned with in this particular discussion is the normalisation boost, which is applied after EQ

HTH.

Keith, this "normalization" issue sounds to my layman ears like the "low frequency boost" issue that IgorZep was lamenting a while back in the Onkyo 818 thread. I'm just curious, as a potential buyer of product with Audyssey... not trying to stir the pot. smile.gif My apologies if the two issues are not related.
post #61939 of 70887
Quote:
Originally Posted by batpig View Post

And just to be clear, this "issue" is not something that you should ever really worry about. IF it is real (and it's still not conclusive that it is) it's extremely rare, triggered by some unusual combination of circumstances (room acoustics, subwoofer position, etc).

I say this just because I want to head off any spiral from "lurkers" suddenly growing worried about potential damage to their systems. I know how internet forms work, somebody mentions some obscure problem and then the paranoia spreads smile.gif

 

LOL - good point bp!

post #61940 of 70887
Quote:
Originally Posted by BarracudaDelGato View Post

Quote:
Originally Posted by kbarnes701 View Post

The reason Chris's answer to Feri's question is not helpful is that Chris only comments on the dB boost/cut that Audyssey applies during the actual equalisation. IOW, Audyssey can only boost by 9dB max when it is trying to deliver the flat frequency response just mentioned above. But that is not what we want to know - as batpig points out to Feri, what we are concerned with in this particular discussion is the normalisation boost, which is applied after EQ

HTH.

Keith, this "normalization" issue sounds to my layman ears like the "low frequency boost" issue that IgorZep was lamenting a while back in the Onkyo 818 thread. I'm just curious, as a potential buyer of product with Audyssey... not trying to stir the pot. smile.gif My apologies if the two issues are not related.

 

I followed Igor's posts with interest but without coming to a definite conclusion. IIRC he was saying that the problem he was experiencing was 818-dependent. Also, Igor was reporting the boost in the satellite channels not the subs, so it is likely not a normalisation issue at all.

 

Although I am certain that the issue is real (it has been described too often to be a figment of the imagination I think), as batpig says above, don't worry about it. It is rare and only happens with certain combinations of equipment and placement. The benefits of XT32 in general vastly outweigh the slim possibility that this will affect you. 

post #61941 of 70887
It makes me wonder if this *issue* could also happen on the main channels too. For example a 4.5" bookshelf woofer that naturally rolls off at 100hz, but Audyssey finds it to roll off at 60hz in room, could it do the +9db thing at say 100-150hz, even with a user changed 80hz x-over? If so, I doubt the speaker in my example is designed to handle those boosted frequencies at loud SPLs?
post #61942 of 70887
batpig, you were absolutely right,...the speculation has begun! OMG eek.gif
post #61943 of 70887
Quote:
Originally Posted by D Bone View Post

It makes me wonder if this *issue* could also happen on the main channels too. For example a 4.5" bookshelf woofer that naturally rolls off at 100hz, but Audyssey finds it to roll off at 60hz in room, could it do the +9db thing at say 100-150hz, even with a user changed 80hz x-over? If so, I doubt the speaker in my example is designed to handle those boosted frequencies at loud SPLs?

 

I really, really wouldn't sweat this....

post #61944 of 70887
Quote:
Originally Posted by mogorf View Post

batpig, you were absolutely right,...the speculation has begun! OMG eek.gif

 

Did you ask Chris yet about normalisation applied after the EQ process (as opposed to filter creation during it)?  If you persist with it, he might actually answer! :)

post #61945 of 70887
Quote:
Originally Posted by batpig View Post

Quote:
Originally Posted by mo949 View Post

Hello Batpig, if my subwoofer rolloff is normally 6db per octave below my subs f3 (if Im saying this right), then will a 9db boost to this region essentially be running my sub above spec?

the audyssey gentleman has been very nice and forthright about my issue I believe. He did say that if the sub is verified to be in working order that audyssey could be boosting regions that my sub cannot handle. My last question to him was pretty much just asking whether that meant audyssey was simply placing my f3 at a lower point than it actually is. What do you think?

I don't really know if there's a clear-cut answer to your first question. Although I would bet the roll-off is steeper than 6dB/octave.

So the initial roll-off below 18hz is 6db/octave based on what the manufacturer told me. The only thing we determined for a fact is that signals are being sent below 18hz at an amplification that is causing the spider coil to slam into something (believe he said cone) and that is what was causing the 'rattling'. He did go on to say it was something that would quickly damage the sub regardless if it was only a few seconds at a time if left unchecked. Disabling audyssey 'fixed' it for now. I don't know why anyone would let their sub get damaged once they started hearing what I was hearing....

As i said, when my part gets here (parts express had it on backorder) I'll update with my further experimenting. I miss the sound audyssey provides me in the mean time.
post #61946 of 70887
Quote:
Originally Posted by kbarnes701 View Post

I really, really wouldn't sweat this....

FAR from sweating, just curious is all.
post #61947 of 70887
Quote:
Originally Posted by kbarnes701 View Post

Quote:
Originally Posted by mo949 View Post

So, is 3 1/2 feet to the side of a corner and 3" from the wall, still considered 'corner placement'? I can get closer to the corner, but not further away than that.

Is that the current location or the suggested new location for the purpose of the test? 

You might also consider putting the sub in a totally different spot just for experimental purposes. I think that at this stage we are not trying to suggest a permanent, good spot for the sub, but rather trying to establish if the sub's location is causing the problem. 

Hi Kbarnes - thanks for your reply (and previous help). So that is the current location. I call it a corner since it is near one, but it is by no means actually in the corner. Also, all spots that I place the mic have clear line of sight to the sub's front firing speaker and I run the test at night to avoid overhead air activity in the day. I will be putting it in a different spot, rerunning audyssey, rerunning the base sweep and will report my findings. I am waiting on my highpass filter and will have a full evening of experimenting once it gets here. I have a very simple straightforward 5.1 setup - i have no doubt I'll find a solution that works; whether its elegant or not is another question.
post #61948 of 70887
Quote:
Originally Posted by batpig View Post

And just to be clear, this "issue" is not something that you should ever really worry about. IF it is real (and it's still not conclusive that it is) it's extremely rare, triggered by some unusual combination of circumstances (room acoustics, subwoofer position, etc).

I say this just because I want to head off any spiral from "lurkers" suddenly growing worried about potential damage to their systems. I know how internet forms work, somebody mentions some obscure problem and then the paranoia spreads smile.gif


i've used audyssey now for 3 years and this is the first time its ever happened to me. It worked great with my budget klipsch subs. Kind of sucks that its my first real premium sub that can handle such low frequencies that it happens on.

If you do have the issue, you'd know it by a mechanical rattle when low effects from movies happen. Dont believe music plays below 20hz, but IDK.
post #61949 of 70887
Quote:
Originally Posted by mo949 View Post

So the initial roll-off below 18hz is 6db/octave based on what the manufacturer told me. The only thing we determined for a fact is that signals are being sent below 18hz at an amplification that is causing the spider coil to slam into something (believe he said cone) and that is what was causing the 'rattling'. He did go on to say it was something that would quickly damage the sub regardless if it was only a few seconds at a time if left unchecked. Disabling audyssey 'fixed' it for now. I don't know why anyone would let their sub get damaged once they started hearing what I was hearing....

As i said, when my part gets here (parts express had it on backorder) I'll update with my further experimenting. I miss the sound audyssey provides me in the mean time.

Mo, lets take a step back from the Audyssey argument for a second. First off, the cone will never actually slap the spider as they are connected together, rather it will hit the spider landing. and/or backplate. A few questions though:

1) Have you pulled the driver to look in the box and see if there is anything else that could be getting in the way and causing this tapping?
2) If you did, did you check the voicecoil leads and see if they might be tapping the cone on larger excursion passages?
3) If you haven't done these things I would strongly suggest trying this. I know it is some work, but sometimes box stuffing can even get between the driver's cone and the motor structure and cause issues. I have also had the VC leads get stretched before and cause tapping on several other drivers in previous setups.

If you do pull the driver, while it is out of the box, try tapping on the cone lightly and work your way all the way around the outside of the cone, tapping about every 3 inches and see if you hear any additional "tapping" coming from inside the driver. This could mean that the woofer is not seated correctly in the gap.

Just some additional things that you could possibly try out if you feel comfortable enough doing so. Beats just sitting on the sub worrying about it biggrin.gif
post #61950 of 70887
Quote:
Originally Posted by beastaudio View Post

Quote:
Originally Posted by mo949 View Post

So the initial roll-off below 18hz is 6db/octave based on what the manufacturer told me. The only thing we determined for a fact is that signals are being sent below 18hz at an amplification that is causing the spider coil to slam into something (believe he said cone) and that is what was causing the 'rattling'. He did go on to say it was something that would quickly damage the sub regardless if it was only a few seconds at a time if left unchecked. Disabling audyssey 'fixed' it for now. I don't know why anyone would let their sub get damaged once they started hearing what I was hearing....

As i said, when my part gets here (parts express had it on backorder) I'll update with my further experimenting. I miss the sound audyssey provides me in the mean time.

Mo, lets take a step back from the Audyssey argument for a second. First off, the cone will never actually slap the spider as they are connected together, rather it will hit the spider landing. and/or backplate. A few questions though:

1) Have you pulled the driver to look in the box and see if there is anything else that could be getting in the way and causing this tapping?
2) If you did, did you check the voicecoil leads and see if they might be tapping the cone on larger excursion passages?
3) If you haven't done these things I would strongly suggest trying this. I know it is some work, but sometimes box stuffing can even get between the driver's cone and the motor structure and cause issues. I have also had the VC leads get stretched before and cause tapping on several other drivers in previous setups.

If you do pull the driver, while it is out of the box, try tapping on the cone lightly and work your way all the way around the outside of the cone, tapping about every 3 inches and see if you hear any additional "tapping" coming from inside the driver. This could mean that the woofer is not seated correctly in the gap.

Just some additional things that you could possibly try out if you feel comfortable enough doing so. Beats just sitting on the sub worrying about it biggrin.gif

lol, you are braver than me and I put 'cone?' because im not technical and might have mangled the object being slammed into. I obviously think your highpass idea is the way to go and sunfire agrees that should work. To clarify what we tested though:

The only thing we did to make sure the sub was working within spec was to set the receiver to reference volume, disable the audyssey room correction, and then run the bass sweep from 0-100hz. We then repeated the test at lower volume. In both instances the sub rolled off with no audible rattle.

Once Audyssey was renabled the rattle happened from 10hz through just over 15hz. That's how we isolated it to the 'software boost'.

I asked if I should even be worried since its not all the time (i mean its not even every movie). He said in this instance yes I should be worried and then gave a technical explanation that I barely understood about electromagnetic field and something trying to leave it and hitting another thing.....in my vocab it was something hitting something - i remembered 'spider coil' since it was such a unique word biggrin.gif

appreciate your help
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AVS › AVS Forum › Audio › Receivers, Amps, and Processors › "Official" Audyssey thread (FAQ in post #51779)