"Official" Audyssey thread (FAQ in post #1) - Page 1971

Quote:

Originally Posted by mogorf 

 

Nope, there is no sucha thing in Audyssey Land as "ideal range" within the "proper range". Within the max allowance any dB value is ideal. 

I don't think that is quite right, Feri. For example. a sub trim set at -14dB is within range, but it is far from ideal. A trim of -14dB will mean that the sub gain is set very high - possibly even into or approaching clipping the sub's amp. As there is no value in having the sub gain set so high, it makes far more sense to reduce it and to allow the AVR trim to rise a little, towards the 'neutral' setting of 0dB. Similarly a sub trim set at +11 means the sub gain is set very low, again for no particularly valuable reason. 

It says this in the FAQ:

"You may want to consider this comment from Ed Mullen, Director of Technology at renowned subwoofer manufacturer SVS:

"A general rule when level matching the subs and the speaker channels is to run the gain hotter at the subs and the AVR sub trim level cooler. That keeps the AVR sub signal clean and allows upward adjustability to run the sub hotter if needed."

In other words, it may be better to turn UP the volume control on the sub so that the AVR sets your trim lower (i.e. to a bigger minus figure)."

I think that is good advice. Keeping within the +/- 3.5dB range allows more flexibility to change the trim levels for whatever reason and also ensures that neither the AVR nor the sub itself are approaching their limits.

So while you are technically correct in what you say, I think there are good reasons to avoid extremes in the trim settings and so does Chris K as it happens: "If MultEQ reports high negative trims (e.g., –12 dB) for the subwoofer, then you should turn the level control further down and run MultEQ again." ;)

Quote:

Originally Posted by batpig 

I remember someone in this thread measuring their SW pre-out and noting that, with extreme *positive* sub trim settings, that the sub channel output from the receiver was actually experiencing some digital clipping. Although the vast majority of reports are of extreme *negative* trims, this is one reason to strive to avoid extreme positive trims.

I have direct experience of that. In my formative months in this hobby I ran Audyssey (MultEQ at that time) and for whatever reason I had set the sub gain to the level recommended by the sub manufacturer - the sub was nothing special -  a 10 inch 300 watt affair - for initial listening. My Audyssey trims came in at +10, so in my innocence I assumed, as this was below the maximum setting, I was good to go. I ran the system like this for one day. And then I noticed, on certain passages with loud bass, terrible distortion emanating from my sub. I had been clipping it for hours without realising it and I had destroyed it. Lesson thoroughly learned. This is why I disagree with Feri's view that so long as the trim is set anywhere in the range, it is good to go. My own experience shows it isn't. Incidentally, my retailer exchanged the sub under warranty for me, which I thought was 'above and beyond' being as I had destroyed it through abuse. After replacing the sub, I raised its gain by a large amount and ran Audyssey again - this put me in firm negative trim territory and I ran that sub like that for well over a year. And then I discovered this thread :)  All anecdotal I know but it ties in with what you say above.

Quote:

Originally Posted by jlpowell84 

can someone explain in a literal sense what audyssey does in the bass equalization calibration?

The short answer is, it's proprietary closely-guarded information so nobody knows. But we can do better than that - have a read of this FAQ section and see if it answers your question:

H. MultEQ: What Is It, How Does It Work?

The basic answer is that Audyssey sets the levels and distances (delays) of each speaker and then uses a mic to 'listen' to the room and then creates a set of inverse filters to counteract room-induced problems - eg peaks at certain frequencies. Some people believe it also has a beneficial effect on reflected sound issues too, but that is deep in the 'secret sauce' and subject to discussion ;)

Quote:

Originally Posted by Selden Ball 

A quibble about part of the subwoofer trim level discussion: if the voltage output of the receiver's subwoofer channel is too low, it might not trigger the sub's Auto-on function when the low frequencies in the sound track have a rather low volume. The higher voltage output by the receiver when the subwoofer channel's trim level is in the +/- 3dB range helps to avoid this problem.

Another good reason to stay 'in the zone', Selden...

Quote:

Originally Posted by djoberg 

Okay, I just got off the phone after speaking to a CS rep in technical support at Onkyo for approximately 20 minutes. The guy *seemed* to be a genuine techie and know his stuff (at times, that is) and his final advice to me was to turn the calibration level down on the sub (in the AVR) AND turn my gain down on my SVS sub. I told him the AVR level was at +11.5dB and the sub gain was at 2/3 and he recommended setting the AVR sub level to as low as I wanted to be based on what I was hearing and to turn the sub gain down to 12 o'clock. I told him that was just "treating the symptoms and not the cause of the problem" and he agreed, but he said, quite dogmatically, "Audyssey is not by any means a perfect calibration system. You can calibrate your speakers with the same set up (i.e. same speakers, same room, same placement of furniture, etc.) 6 times and come up with 6 different outcomes." I told him I had, in measure, experienced that in the 7 or 8 calibrations I did yesterday, but that there still had to something wrong with either my sub or the AVR's sub out if one has to set the gain so high to achieve a satisfactory sub level. He then said, "Audyssey's mic may be having a hard time with your sub for whatever reason," and then he told me that he didn't believe anything was wrong with the Onkyo (or my sub) and not to worry about it. He even went on to say that there are a lot of people that call in and complain about Audyssey and that they're not satisifed with what they're hearing, and they end up doing what he's telling me to do...set my trim levels and sub gain to my liking. He did agree that the sub gain should NOT be set past the 12 o'clock setting but as long as I was able to get the trim levels to below +12dB in some of my calibrations I should be alright. He ended our conversation by trying to assure me that he didn't believe any damage could be done to either my sub or the AVR in light of what I've experienced.We'll see about that (or maybe not...maybe I'll just return the unit).

I am going to *try* what he said and believe my ears. My goal is to have a seamless blend between my sub and other channels (like I did with my Pioneer) without compromising the performance of my PC12-NSD, so we'll see what happens.

Typical useless manufacturer support person. All that 'advice' is BS. 

More BS. You can indeed get slightly different results from each calibration, usually because the mic is not in the same locations each time. But this will not apply to distance and levels. If you make 1000 measurement runs, and don't move the mic at all, you will get exactly the same level and distance settings every time. The experience you are having is not an Audyssey problem (unless your mic is damaged but it is hard to see how it sets the other speakers correctly if that is so) - it is a sub or an AVR problem. If you look back through the 60,000 posts in this thread, you will not find one single instance of Audyssey setting a sub at +12dB when the sub gain is set correctly. (I have actually read all 60,000 posts believe it or not, as have several other 'regulars' here). So the question is, is it the sub or the AVR?  Given that you never had these problems with your old Pioneer, my money is on the AVR and I personally would return it while you can. It may be a blessing in disguise - you may decide to hang fire on replacing that Pioneer until you can get an 818 with MultEQ XT32....

Quote:

Originally Posted by mogorf 

Quote:

Originally Posted by kbarnes701 

I don't think that is quite right, Feri. For example. a sub trim set at -14dB is within range, but it is far from ideal. A trim of -14dB will mean that the sub gain is set very high - possibly even into or approaching clipping the sub's amp. As there is no value in having the sub gain set so high, it makes far more sense to reduce it and to allow the AVR trim to rise a little, towards the 'neutral' setting of 0dB. Similarly a sub trim set at +11 means the sub gain is set very low, again for no particularly valuable reason.

Keith et all,

Let's dig a bit deepeer into this sub trim phenomenon. Firstly, let's just look at the sub level adjustment schemes of Audyssey because that may be a bit different than the setting of the satellites that do not have a gain control knob.

Ok, so, what is the ultimate goal of Audyssey's sub level setting? To achive 85 dB SPL in the LFE channel at the tip of the Audyssey mic sitting at the MLP at seated ear heigth with a -30 dBfs test signal sent out through the subwoofer. Right?

Then, what is a gain knob on the back side of the sub? A gain knob on the plate amplifier is basically just a small potentiometer (variable resistor) that allows adjusting the incoming signal to the amplifier so that the amplifier will work well with the subwoofer driver.

Now let's go back to Audyssey trims. If the gain knob on the sub is turned down Audyssey has to increase the trim and if the gain knob is turned up Audyssey will have to decrease the trim. Why? Because in both cases the goal is to reach 85 dB SPL at the MLP. Typically Audyssey has a window of 24 dBs (Denons) to fit into this range. Where the trim will stop witin this range is not important, the only thing important is that SPL should be 85 dB at the MLP. On a second note, as you can see, this range does not have a center (or neutral value, as you say) or in other words a center value is not defined here, only the start (-12 dB) and the stop (+12 dB) levels are set up. This is why I said there is no ideal range within the full range, coz based on the above any trim value within the range of +/- 12 dB that is necessary to produce the reference level of 85 dB is OK. And there will only be one such level provided the gain knob is not touched.
Finally, in case the subwoofer is clipping it can never be attributed to the trim level setting of Audyssey, since Audyssey has done nothing else than setting up the subwoofer level to reference.

@Selden:

My sub also has that funny feature called auto-sleep, but I wan't my sub to be awake while I'm also awake, therefore I just simply turn that switch to OFF.

We'll have to agree to disagree on this, Feri. I think the case for staying within the +/-3.5dB range (approximately) is overwhelming, for the reasons I gave (and which Selden added to).