# Don't always trust the auto calibration



## TomFord (Jul 15, 2014)

Have noticed a trend in talking with friends & HT guys online about the auto calibration on the receivers. Quite a few of them aren't setting the crossover points anywhere near where they're supposed to be. Was helping a guy find a replacement Klipsch driver for his sub (don't ever set your sub above 75% gain. Like him you won't be able to notice hardly any difference & your likely to blow it like he did) & his Auddessy always set his back left & right at 200 Hz when the frequency range of the speakers started in the low 50's (55 I believe) asked him to move his left & right surround speakers to the left & right rear to be sure it wasn't faulty speakers/connection & the Auddessy set them at 200 Hz again. He was amazed at the improvement of switching it to 60 then 80. Neighbor had the same issue with his front highs being set at 150 Hz. Frequency range on them starts at 46 Hz & has no business being set to 150. Been a bit surprised at the lack of knowledge and the blind faith put behind a quality name like Auddessy or AccuEQ. 
Recommend looking up the specs of each speaker & checking to see if it's calibrating near the beginning of the range. Also, if your front L & R are smaller than 8' & you have a sub don't set them on full band. The sub is built for the first 3 octaves, let it do its job, plus when you set a speaker too low your shortening the life on it & or getting a lesser quality than what your gear can produce. Be surprised if many of the L & R out there could even hit 30 Hz if they're not 8'. Last try all your crossover points at 80 Hz which is what THX recommends & it sounds great on mine. 

These are just recommendations, do what sounds best to you & use your gear however you want. Just wanted to give you guys a heads up on the calibration errors


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## Kal Rubinson (Aug 3, 2006)

TomFord said:


> Have noticed a trend in talking with friends & HT guys online about the auto calibration on the receivers. Quite a few of them aren't setting the crossover points anywhere near where they're supposed to be. Was helping a guy find a replacement Klipsch driver for his sub (don't ever set your sub above 75% gain. Like him you won't be able to notice hardly any difference & your likely to blow it like he did) & his Auddessy always set his back left & right at 200 Hz when the frequency range of the speakers started in the low 50's (55 I believe) asked him to move his left & right surround speakers to the left & right rear to be sure it wasn't faulty speakers/connection & the Auddessy set them at 200 Hz again. He was amazed at the improvement of switching it to 60 then 80. Neighbor had the same issue with his front highs being set at 150 Hz. Frequency range on them starts at 46 Hz & has no business being set to 150.


Of course, one should not take any random result as authoritative but the problem is that such programs are proffered as simple and fool-proof and they are not. Nonetheless, when Audyssey or another auto-EQ system does this, there is almost always a reason due to room/setup anomalies or careless use. Finding out WHY is the only way to, ultimately, get it right and that generally requires more knowledge and tools than is possessed by the average user.

Still, just setting the crossover from 200Hz to 60/80Hz is hardly an ideal solution since it means that the intervening frequency band is not equalized.


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## willis7469 (Jan 31, 2014)

Good point Kal. To elaborate, that's because audyssey will EQ above the crossover it's set. If you raise the crossover point, it still applies all the filters. If you lower it, the benefit will be fuller sound from that speaker, but the new frequency range won't have any EQ filters applied. Audyssey sets my mains to full, but I usually cross them at 50. I'm trying 80 now. So far so good. For example if it were reversed, and audyssey set my mains to 80, and I rolled them down to 50, the range between 50 and 80 would be "un" eq'd.


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## bigk_54 (Nov 26, 2010)

Tom, awesome write up seeings how I've been banging my head on the wall for a 2-3 weeks now! I've been playing with levels and configurations in all my spare time

Check my thread out, would love to know your thoughts 
http://www.hometheatershack.com/forums/system-setup-connection/97401-established-system-set-up.html


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## tonyvdb (Sep 5, 2007)

Agree, the auto calibration wont always get it right however what is more important is to make sure you have the placement of the mic correct. Many many people do not do it right. 
Room acoustics can play a huge part in what the mic "hears" even though the speaker may go down to 60Hz does not mean that the in room response is going to reproduce that at the listening position.


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## willis7469 (Jan 31, 2014)

I wonder if Toms neighbors height channels were set at 150hz because height channels don't operate full range? Anybody?


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## NBPk402 (Feb 21, 2012)

Audyssey was setting my front 3 channels to anywhere from 150Hz to 250Hz. I ended up solving the problem by ditching my crossovers, and bi-amping the speakers. I ended up lowering the gain on my Horns, and raising the gain on my Bass Bins until I got my crossover to 80Hz.


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## Peter Loeser (Aug 11, 2012)

tonyvdb said:


> Agree, the auto calibration wont always get it right however what is more important is to make sure you have the placement of the mic correct. Many many people do not do it right.
> Room acoustics can play a huge part in what the mic "hears" even though the speaker may go down to 60Hz does not mean that the in room response is going to reproduce that at the listening position.


Agreed 100%. A speaker can perform drastically differently in a room than it does on paper (usually in an anechoic environment). The room correction software knows nothing about the speaker specs, and therefore can only work with what it hears as Tony says. Room size/shape, sub/speaker/mic placement, and acoustics will all impact the results. Some anomalies can't be corrected electronically, so the software must decide the best solution that can be done with DSP given the info it has. Room correction is a quick and easy way to extract better performance from a system with a fixed layout, for those who do not have the tools, time, or interest to do a manual analysis of their system in their room. It's not going to make an un-treated room with a less than ideal layout sound like a studio. They generally work pretty well, but should not be considered a substitute for proper speaker placement and room treatment.


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## TomFord (Jul 15, 2014)

Bigk, sure thing. Wis I had help 5 mon the ago when I started, so I'd be happy to. Just send me a private message if I don't get you an answer by tomorrow 

Cal - "Still, just setting the crossover from 200Hz to 60/80Hz is hardly an ideal solution since it means that the intervening frequency is not equalized"

Cal are you only referring to systems without a subwoofer? Could you clarify? Doesn't make sense the way I read it. Even without a sub where the beginning of the signal that's audible, 20-30 or 20-40Hz depending on the quality of your front speakers is handled by the sub IF your front L & R are not set to full band. If they are set to full every other speaker (let's say they rest are set at 80Hz which is what they should be at for most in my opinion) in your system sends everything that's asked of it below 80Hz to the front L & R channels. Another reason few should have them set to full band, not many can handle that range nor the volume of it. What isn't equalized? They're are only 2 scenarios. 1st is your sub or mains can't handle producing the low bass of 20-30Hz. 2nd is they can. Regardless of the settings those are the only two outcomes. Sure, adjusting settings can help with the discrepancy but it's 1 of the 2 scenarios nonetheless. What's not equalized?

Read more: http://www.hometheatershack.com/for...ays-trust-auto-calibration.html#ixzz3IivREXUe


willis7469 said:


> Good point Kal. To elaborate, that's because audyssey will EQ above the crossover it's set. If you raise the crossover point, it still applies all the filters. If you lower it, the benefit will be fuller sound from that speaker, but the new frequency range won't have any EQ filters applied. Audyssey sets my mains to full, but I usually cross them at 50. I'm trying 80 now. So far so good. For example if it were reversed, and audyssey set my mains to 80, and I rolled them down to 50, the range between 50 and 80 would be "un" eq'd.


Do you have a sub?

Never owned Audyssey. Does it adjust or set anything aside from distance, crossover, and level calibration? Don't believe it does, yet my apologies if incorrect. I don't understand how 50-80 would be "un eq'd", how do you mean? Is it making an adjustment that no other auto calibration sets? If it set your mains at 80 & you switched them to 50, given your speakers can produce that which most can, nothing should be un eq'd. The subwoofer would simply be passing off what it produces at 50Hz opposed to 80Hz for the mains, not the other channels . If you didn't have a sub this wouldn't apply as it would force you to set it at full brand, completly ignoring what the mains can produce. 
I don't mean how they spin the description so ridiculously in the advertising that probably has Joe Consumer saying "I don't know what that means, but yeah" Like how is says something like "measures over 10,000 points in your listening place" all its doing is transmitting a signal and measuring what that signals level at the listening point where the microphone is placed vs what it transmitted from the speaker. If it had a camera, transmitted lights using a variation of waves like gamma which you couldn't do, or if it used radio waves which it does along with magnetic fields (what an MRI does) to do actual imaging then I'd defer. That fancy description of measing 10,000 points can be easily outdone. Go yell at your neighbor, if he's 2 houses down & can hear it you just measured at least 100,000 points. Know the Auddessy & other brands help, especially those new or uneducated in home theater. Too many defer to its simplistic methods when a few hours of research with a true understanding and the majority of people are better than any auto calibration


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## Andre (Feb 15, 2010)

MultEQ measures the roll off of the speaker in your room. It doesn't matter what the spec sheet says. The room and speaker position change the low frequency performance. So, MultEQ will stop applying correction below 150 Hz in your case. If you move the crossover lower than that then MultEQ will not be applying correction below it. Sound will still play, but we don't recommend doing that.

https://audyssey.zendesk.com/entries/438840-Changing-the-cross-over-settings-after-running-Audyssey


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## willis7469 (Jan 31, 2014)

Hi tom. Yes, I actually am using 3 subs in my system with a 4th to follow soon. 
Just to be clear, Audyssey does all the measurements you mentioned. It also does EQ for a flat response. That's why the majority of us rely on it. That's NOT to say one should use it blindly. The un-eq'd" statements were with that in mind, and why that is, is because when audyssey "does its thing", it will only EQ above the point at which it has set its crossover. That's why it doesn't matter if you raise the crossover after the cal. All the filters will still be in place. If you lower it however, the range between where audyssey set the crossover, and a new "lower hz" entry(rolloff range notwithstanding) won't be equalized by Audyssey. I hope that was more clear an explanation.


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## willis7469 (Jan 31, 2014)

Tom, here's some good reading. Plenty of links to side track you. Lol. You mentioned not having audyssey, so I thought this might shed a little light. It's proof of why you should use audyssey, why you shouldn't trust it blindly, and how to use it to it's potential.


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## Kal Rubinson (Aug 3, 2006)

TomFord said:


> Bigk, sure thing. Wis I had help 5 mon the ago when I started, so I'd be happy to. Just send me a private message if I don't get you an answer by tomorrow
> 
> Cal - "Still, just setting the crossover from 200Hz to 60/80Hz is hardly an ideal solution since it means that the intervening frequency is not equalized"
> 
> ...


Here's the point. 
1. Run Audyssey and it sets the crossover to 200Hz and EQ's down to 200Hz but not below.
2. Afterwards, you reset the crossover to 80Hz. The result is that Audyssey will EQ the speaker only down to 200Hz and it will EQ the sub only up to 80 or 120Hz. The range in between is not EQ-ed.


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## chashint (Jan 12, 2011)

I am not necessarily 'all in' on any of the room correction schemes but they are better than nothing and give the average consumer the ability to at least set levels and distances.
My experience with audessey and MCACC is, both set the crossover too low or identify speakers as full range when they are not so there's no crossover.
All in all it's probably better to weight the algorithm that direction that the other direction. 
By this time I would think the sound mix would take into account surround speakers and even front mains are not full range (even in theaters) and the bulk of frequencies 80Hz and below would simply be on the LFE channel.


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