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Can Audyssey Guarantee Flat Bass to Very Low Frequencies?

  • Yes

    Votes: 2 12.5%
  • No

    Votes: 14 87.5%
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Discussion Starter · #1 ·
The new Chane SBE-118 product page claims that "Simply run Audyssey or another advanced bass setup routine on your system including one or more Chane SBE-118s and you're done: Flat bass to very low frequencies, even in smaller spaces."


To me, this seems an untenable claim for any subwoofer as a generality given the quite different effects that a room and subwoofer placement could have on a sub's performance, much less for a sealed, passive subwoofer that has no internal EQ adjustment of its own (as might be present with some sealed sub with built in amps). At the very least, my understanding is that Audyssey does not EQ for nulls, which are present in a lot of rooms.


Now Jon Lane has flat out said my assertion is wrong:
Quote:
Originally Posted by Jon Lane  /t/1520548/home-theater-beginner-400-600-budget/30#post_24454150


Simply untrue - we provide maximum output levels by frequency band per industry standard.


Assuming you understand how dozens of dB are routinely injected into bass systems with less volume displacement then these, and assuming you understand Vd and typical native responses, and especially assuming you grasp room effects, we both know your assertion isn't the case.


We make no "bold statements" for products we simply know will do what we say they will. We make factual statements backed by data.

Am I completely off my rocker? Or is it generally accepted on the AVS subwoofer forum that Audyssey is not the guaranteed cure all for producing a "flat" response with any sub. Thus the poll. If manufacturers are going to start making this claim for their subs, then the poll that will show the range of overall opinion for newbies trying to make decisions about sub buying. And a general discussion seems helpful as well.
 

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cel 4145, cel 4145....... You misunderstood the reference and are taking things out of the context. Life does offer more than looking for every chance to bash this company. And don't bring up the past and past arguments, at some point you need to move forward. The subs have not even hit to market, just wait and then you can go on your rant.
 

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Discussion Starter · #3 ·

Quote:
Originally Posted by derrickdj1  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24456344


cel 4145, cel 4145....... You misunderstood the reference and are taking things out of the context. Life does offer more than looking for every chance to bash this company. And don't bring up the past and past arguments, at some point you need to move forward. The subs have not even hit to market, just wait and then you can go on your rant.

Sorry, I don't know what you are talking about "the reference." I'm interested in examining the audio science of this claim about Audyssey since I was told by the company I didn't know what I was talking about when I said it was untenable.So the subject of this thread is that claim, not me. If you have something to add to the audio science discussion of that claim, that's fine.
 

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I am not exactly sure what threads you guys are talking about, but some things to consider on this subject:
  1. Very few rooms will permit a flat response, whether the sub has it or not.
  2. There are plenty of post-audyssey responses that were shown to be pretty rough.
  3. Any sub with a non flat response will essentially be bottle-necked by the weakest region of its performance from the perspective of accurate playback.


Therefore the most efficient approach is for the sub to have the flattest response that can be natively had, pre-equalization, and that goes for any onboard processing in the sub's amp as well. The best approach from what I can see is to have multiple linear-response subs placed so that as little equalization is needed to get a flat response at the listening position. Flattening the response at listening position through multiples doesn't work if the sub's own response is wacky. The ideal system wouldn't use Audyssey or any EQing at all, but, of course, there is the ideal, and then there is the real world. I suppose ultimately if you can achieve a flat response in-room with a non-flat sub through a room correction EQ like Audyssey, that is great, but I have seen enough room responses, including my own system, where it's not the only tool I'd want to rely on for that goal.
 

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Quote:
Originally Posted by cel4145  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24455913


Am I completely off my rocker?
Maybe.


But as for the claim that Audyssey will give flat bass to very low frequencies, no. Even if it works fully parametrically and has at least ten bands assigned to the sub woofer pass band. and I don't believe that's the case, you can't EQ away room related peaks and nulls outside of a very small LP. That requires either multiple subs or a room with no ceiling and no walls.

I agree that the claims made on that site should get no more a reaction than "So?", because whatever advantages they claim for using Audyssey etc with their sub also apply to every other sub in existence.
 
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Discussion Starter · #6 ·

Quote:
Originally Posted by shadyJ  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24456464


I am not exactly sure what threads you guys are talking about, but some things to consider on this subject:
  1. Very few rooms will permit a flat response, whether the sub has it or not.

And that's the big thing right there to me. It's a bad marketing claim regardless of the sub's native frequency response performance. Then add in that the sub is a passive sealed sub, a lot of people would be in for a rude awakening if they took that advice and then measured the sub in their room.
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by Bill Fitzmaurice  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24456518


Maybe.

Thanks. LOL
Quote:
Originally Posted by Bill Fitzmaurice  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24456518


But as for the claim that Audyssey will give flat bass to very low frequencies, no. Even if it works fully parametrically and has at least ten bands assigned to the sub woofer pass band. and I don't believe that's the case, you can't EQ away room related peaks and nulls outside of a very small LP. That requires either multiple subs or a room with no ceiling and no walls.

I agree that the claims made on that site should get no more a reaction than "So?", because whatever advantages they claim for using Audyssey etc with their sub also apply to every other sub in existence.

I've never understood exactly how the EQ filters work in Audyssey MultEQ, even after Chris Kyriakakis's explanation . I can see that there is some acoustical modeling prediction in there, but is the filter concept a lot different from PEQ?
 

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Quote:
Originally Posted by cel4145  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24457144


Thanks. LOL

I've never understood exactly how the EQ filters work in Audyssey MultEQ, even after Chris Kyriakakis's explanation . I can see that there is some acoustical modeling prediction in there, but is the filter concept a lot different from PEQ?
I don't have Audyssey, so I don't know exactly what it does. I have MCACC, but I don't use it, I use a stand alone DSP. In any event, you need a lot of processing down in the low end, along the lines of the FBD that they recommend for use with REW. I'm inclined to think that Audyssey doesn't have ten or more parametric filters dedicated to below 80Hz.
 

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Discussion Starter · #9 ·

Quote:
Originally Posted by Bill Fitzmaurice  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24457222


I don't have Audyssey, so I don't know exactly what it does. I have MCACC, but I don't use it, I use a stand alone DSP. In any event, you need a lot of processing down in the low end, along the lines of the FBD that they recommend for use with REW. I'm inclined to think that Audyssey doesn't have ten or more parametric filters dedicated to below 80Hz.

Supposedly Audyssey MultEQ has 128x filter resolution multipliers for subs and 512x for the X32 versions, whatever that means. I guess we won't really know until their first patent runs out.
 

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I doubt that the number of taps on the eq is part of a patent. Trade secret. Patents are by definition fully public. Might as well wait for Coke to divulge their formula.


Whatever it is, its different from normal eqs, being fir rather than iir filters.


Whether the end result differs significantly is a different question.
 

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Quote:
Originally Posted by Bill Fitzmaurice  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24456518


Maybe.


But as for the claim that Audyssey will give flat bass to very low frequencies, no. Even if it works fully parametrically and has at least ten bands assigned to the sub woofer pass band. and I don't believe that's the case, you can't EQ away room related peaks and nulls outside of a very small LP. That requires either multiple subs or a room with no ceiling and no walls.

I agree that the claims made on that site should get no more a reaction than "So?", because whatever advantages they claim for using Audyssey etc with their sub also apply to every other sub in existence.

Bill, this statement is on target to not get a reaction of more than So. From reading the Chane site I gather their statement to be a general statement, that most people can get good results using Audyssey if they plan to not use anything else.. This statement was geared toward people that don't want to do tinkering with REW, Mini DSP or PEQ. Is any calibration system perfect. No, or there would not be so many. It is a well know fact that multiple subwoofers is the best way to get an even or as best that can be achieved response in a particular room. There really is not much to discussion. Maybe the thread should be on things to do to achieve a flat frequency response using multiple subwoofers, autocalbration, and advance DSP/PEQ. A thread based on this would be much more useful to the members.
 

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Discussion Starter · #12 ·

Quote:
Originally Posted by derrickdj1  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24457500


From reading the Chane site I gather their statement to be a general statement, that most people can get good results using Audyssey if they plan to not use anything else..

That's not what the statement says, though. It makes specific claims about "flat bass"--more than once. If it said something like "good bass," that would fit with what you have just said. Instead, the statement clearly refers to a specific type of frequency response.
 

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Quote:
Originally Posted by cel4145  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24457297


Supposedly Audyssey MultEQ has 128x filter resolution multipliers for subs and 512x for the X32 versions, whatever that means. I guess we won't really know until their first patent runs out.

It is an interesting topic.

Then I will do the tests to see MultEQ XT32 makes my Denon X4000. I will connect the subwoofer output directly X4000 Denon audio input of my sound card. I'll measure to see unfiltered Aduyssey really a flat signal is sent and then another with Audyssey filters activated. The LPF of LFE to 120hz will.


Necestio few minutes and when finished, put the results here. So we can know for sure how many Aplia XT32 filters. At least it does in my particular situation.


What do you think?


I'll do this, I wait a few minutes sitting.
 

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Here I have the results of what makes XT32 with 512x filters for the subwoofer.


The black line represents the linear response Audyssey OFF.

The green line represents the Audyssey filters applied to the subwoofer under the conditions of my team.


It seems that applying multiple filters, see How many in total?

 

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The limitation of this particular highly regarded calibration system and some of the other calibration systems is a good topic. As I have stated, this tread should have a different name if the limitation of this particular calibration system is under question. A dedicated thread to help forum members that want or trying to achieve a flat frequency response is a good topic.
 

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Discussion Starter · #16 ·

Quote:
Originally Posted by derrickdj1  /t/1521571/can-audyssey-guarantee-flat-bass-to-very-low-frequencies#post_24457672


A dedicated thread to help forum members that want or trying to achieve a flat frequency response is a good topic.

Good idea, but a different topic. I would encourage you to go start a thread on that topic.
 

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Now the results of Audyssey in my listening point.

Linea Black Audyssey ON.

Audyssey OFF Green Line.


The subwoofer I use, is to use as avatar, in 20Hz mode.




 

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I forgot.


My room is extremely small, 10 m2. The subwoofer too loud for the room. It is located in the corner.

The starting point without EQ, it's good. But with Audyssey is better, it seems that is working perfectly in my small room.


I'll take some pictures of spectrogram to see com compared before and after the EQ.
 

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Here is the spectrogram.

Audyssey OFF





Audyssey ON


 
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