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post #1 of 13 Old 12-20-2014, 04:25 PM - Thread Starter
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Question Need help with EQ definition

Hey guys-
I know most of you are experts when it comes to this so I thought I'd ask so that I can get a better understanding on how to properly calibrate my home theater.

My current setup consists of a Pioneer Elite SC-71 hooked up to two Martin Logan Motion 40's (Bi-Amp). I've been tweaking the EQ on the SC-71 quite often but haven't hit the sweet spot yet. With that said, I was hoping some of you could shine some light on the frequencies available to me in the MCACC EQ setup:

Frequencies available to me from left to right:

63 hz
125 hz
250 hz
500 hz
1k hz
2k hz
4k hz
8k hz
16k hz
TRIM

I'd like a quick run down of what the frequencies control so that I can better understand my current setup to tweak it to my preference. I appreciate any help that can be given.

Thanks!

TV: Panasonic Viera VT50 55 | A/V Receiver: Pioneer Elite SC-71 | Speakers: Martin Logan Motion 40's (Bi-Amped) | Cables: AudioQuest Cinnamon HDMI Cables + AudioQuest Rocket 33's (split)
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post #2 of 13 Old 12-20-2014, 04:38 PM
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Do you mean what instruments are at those frequencies? There are charts that show what frequencies are covered by particular instruments:


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post #3 of 13 Old 12-20-2014, 05:23 PM - Thread Starter
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Originally Posted by mtn-tech View Post
Do you mean what instruments are at those frequencies? There are charts that show what frequencies are covered by particular instruments:

Sorry I should have been a bit clearer, I'm looking to optimize the sound for home theater use, basically get great vocals, highs, mids and lows. Not too bright but not too warm either, I just need some help to determine what these frequencies will basically control even though I know there are many ways to interpret them. Again, this is for home theater usage.

Thanks!

TV: Panasonic Viera VT50 55 | A/V Receiver: Pioneer Elite SC-71 | Speakers: Martin Logan Motion 40's (Bi-Amped) | Cables: AudioQuest Cinnamon HDMI Cables + AudioQuest Rocket 33's (split)
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post #4 of 13 Old 12-20-2014, 06:16 PM
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home theater geeks just recently did a interview regarding sound and standards apparently what has been a base reference is all wrong lucas films thx was supposed to standardize how ever what was made a standard was the equipment and not how the source was created and implemented so what your attempting to do is correct a bad source from the beginning all by ear and geuss work so what your trying to is attempt to correct bad sound with no reference and any reference your going to find is not going to be Acquret so basically your going to have to do everything by ear to tell you how bad the industry is one theater was found to have blown drivers there is a 250 page downloadble document that explains most of this
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post #5 of 13 Old 12-20-2014, 06:20 PM
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Quote:
Originally Posted by TL24 View Post
I just need some help to determine what these frequencies will basically control even though I know there are many ways to interpret them.
They tell you exactly what they control, that specific frequency and you can either boost or cut those frequencies. It's better to cut than to boost. Anyway without a measurement mic you'll never know what frequencies need attenuation and all you can do is is subjectively play around with it until you think it sounds good. No one on the internet can tell you what to set your EQ to because everyone's speakers and room are completely different.

Even though this video is aimed toward car audio the concept is the same. Pay attention to the Graphic EQ bits as that's what you appear to have from your post (I'm not familiar with Pioneer AVRs or MCACC).
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post #6 of 13 Old 12-21-2014, 10:53 AM - Thread Starter
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Originally Posted by |Tch0rT| View Post
They tell you exactly what they control, that specific frequency and you can either boost or cut those frequencies. It's better to cut than to boost. Anyway without a measurement mic you'll never know what frequencies need attenuation and all you can do is is subjectively play around with it until you think it sounds good. No one on the internet can tell you what to set your EQ to because everyone's speakers and room are completely different.

Even though this video is aimed toward car audio the concept is the same. Pay attention to the Graphic EQ bits as that's what you appear to have from your post (I'm not familiar with Pioneer AVRs or MCACC).
https://www.youtube.com/watch?v=GXIkWiB09rw

That's awesome man! Thanks for the link! I'll definitely be watching this video tonight and then calibrating my EQ based on the info in this video!


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TV: Panasonic Viera VT50 55 | A/V Receiver: Pioneer Elite SC-71 | Speakers: Martin Logan Motion 40's (Bi-Amped) | Cables: AudioQuest Cinnamon HDMI Cables + AudioQuest Rocket 33's (split)
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post #7 of 13 Old 12-21-2014, 12:35 PM
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Originally Posted by drwho2012 View Post
... lucas films thx was supposed to standardize how ever what was made a standard was the equipment and not how the source was created ...
Then how do you explain all the THX dvds of the dvd era???
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post #8 of 13 Old 12-22-2014, 06:44 PM
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Originally Posted by TL24 View Post
Hey guys-
I know most of you are experts when it comes to this so I thought I'd ask so that I can get a better understanding on how to properly calibrate my home theater.

My current setup consists of a Pioneer Elite SC-71 hooked up to two Martin Logan Motion 40's (Bi-Amp). I've been tweaking the EQ on the SC-71 quite often but haven't hit the sweet spot yet. With that said, I was hoping some of you could shine some light on the frequencies available to me in the MCACC EQ setup:

Frequencies available to me from left to right:

63 hz
125 hz
250 hz
500 hz
1k hz
2k hz
4k hz
8k hz
16k hz
TRIM

I'd like a quick run down of what the frequencies control so that I can better understand my current setup to tweak it to my preference. I appreciate any help that can be given.

Thanks!
The purpose of an "equalizer" is to "equalize" all frequencies so they are all played back at "equal" volume. To properly use an equalizer, you need to know what frequencies in your system are being played back unequally to the other frequencies. Then you can target those frequencies with the equalizer.

For example, in the following graph:



... there is a large peak at 40 Hz, a deep depression at 90 Hz and then a wide peak from 100 to about 160 Hz. To "equalize" this graph to get all the frequencies at equal volume, you would need to cut the levels of the 40 Hz peak, boost the levels of the 90 Hz depression, and broadly cut from 100 to 160 Hz. If you did this, the resultant graph would look something like this:



This is still not a "flat curve, with all frequencies being played back "equally loud" but it is a big improvement over the original graph. In the original, the discrepancy between the loudest frequencies and the softest frequencies is over 25 dB. In the EQ'd graph, the discrepancy has been reduced to less than12 dB.

Note that the deepest depression at 90 Hz has been improved, but it still is the worst part of the graph. This is because deep depressions in the frequency response are caused by cancellations, where a reflected soundwave combines with another reflected soundwave, but the 2 waves are out of phase with each other. In that scenario, the negative side of one wave will cancel the positive side of the other wave, and the result is... no wave. This is what happening at 90 Hz in the original graph.

How does this impact your use of the "equalizer" in your Pioneer receiver? First, you need to realize you need knowledge of your system's frequency response before you can improve it. Unless you have perfect pitch, and you can perfectly identify the frequencies that are out of balance in your system, (which seems unlikely since you are here asking for specifically this kind of help), the only way to identify these problems is to *measure* them. There are lots of systems that can help you measure your system. Pick one and use it.

Second, you need to realize that your "equalizer" is a "graphic" equalizer. The frequency bands are "fixed" and you can't change them. Also, widths of the filters, (i.e., the range over which the filters affect the response), are fixed and you can't change them. So, using the example of the graphs above, you can't take the band at 63 Hz and move it to 40 Hz to cut the 40 Hz peak. Also, you can't take the filter at 125 Hz and make it broad enough to cover the whole range of the peak above and below 125 Hz. You don't even have a filter at 90 Hz, so you couldn't boost that range, even if it could have a beneficial effect.

Bottom line, an octave-based graphic EQ, such as the one in your Pioneer receiver, is essentially worthless as an "equalizer." At best, it's a glorified set of tone controls. Without a complete set of in-room measurements of your system, you're basically just taking a "shot in the dark" whether the application of the "EQ" filters are actually beneficial, or whether they even address the actual problems that exist in your system.

With your Pioneer receiver, you would be much better off using the on-board MCACC system with the Standing Wave Multipoint. That system actually measures the frequency response of your system in your room. The filters in that system are automatically adjustable for frequency and width, and they have a much better chance of correcting the actual problems that exist in your system in your room.

Only in-room system measurements will tell you exactly how well either system will work.

Craig
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Last edited by craig john; 12-22-2014 at 06:56 PM.
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post #9 of 13 Old 01-02-2015, 10:03 AM
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without a measurement mic you'll never know what frequencies need attenuation and all you can do is is subjectively play around with it until you think it sounds good. No one on the internet can tell you what to set your EQ to because everyone's speakers and room are completely different.
Right - if your AVR doesn't display its room correction results graphically (if it only has "auto" room correction with no display) then you need to measure your system's response IN YOUR ROOM with a calibrated mic and software to show you the results - then it will be obvious what frequencies need to be adjusted. The MiniDSP mic and free REW software are the best / easiest place to start - you just need a computer and there is a lot of help here on AVS on how to use it / interpret the results.
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post #10 of 13 Old 01-02-2015, 07:45 PM
 
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Originally Posted by drwho2012 View Post
home theater geeks just recently did a interview regarding sound and standards apparently what has been a base reference is all wrong lucas films thx was supposed to standardize how ever what was made a standard was the equipment and not how the source was created and implemented so what your attempting to do is correct a bad source from the beginning all by ear and geuss work so what your trying to is attempt to correct bad sound with no reference and any reference your going to find is not going to be Acquret so basically your going to have to do everything by ear to tell you how bad the industry is one theater was found to have blown drivers there is a 250 page downloadble document that explains most of this
The Home Theater Geeks show you referenced has been largely discredited (at least the two fellows with SMPTE who were on the show) on this forum for their lack of understanding of industry standards, specifically, the X-curve they so roundly derided. However, if they actually understood what it was all about, they'd have had a very different view. Those two shows were an unfortunate shambles.

THX never set a base (bass?) reference, so it's impossible for them to be wrong. THX/Lucasfilm didn't change any standards relating to what was recorded on film soundtracks. THX changed the capabilities of sound reproduction in theaters (and dub stages), but they were performance standards only, and not accepted industry wide. There were a certain number of THX theaters, and many dub stages conformed to THX specifications. For example, THX didn't impose or change the X-curve.

THX standardized on one piece of theater equipment only, the active crossover. Otherwise THX qualified theaters could be built with any equipment that hit their specifications.

As to "how bad the industry is"... theaters with blow drivers is neither new nor uncommon. It has nothing to do with THX, or the X-curve, but, aside from the 250 page document (have you actually read it?) what the SMPTE guys were suggesting would, in fact, likely blow HF drivers quickly around the country. That's how misguided they are with their so-called "report".

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Then how do you explain all the THX dvds of the dvd era???
THX attempted to get involved with the production of DVDs, and created some specific minimum specifications for them that included both audio and video. Their specifications fit within existing industry capabilities, and did not impose different or incompatible standards. A THX DVD is of course compatible with any player, it's just a set of minimum quality standards, nothing else. Think of a THX DVD as one that has been meticulously produced to have the best possible picture and sound.

Note to drwho2012: In 2015 we still are forced to end each sentence with a period (.) and begin each sentence with an upper-case letter. I know it's hard for a time lord to keep up with all the different customs, just thought you'd like to know how to get your posts to fit in better in this time. It helps them to be more easily understood by us less advanced beings.
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post #11 of 13 Old 01-02-2015, 11:54 PM
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lucas standardized equipment and how sound was supposed to be recreated but up lintel just recently the whole approach was off as to the how the sound was created in the first place was of there was a podcast on this subject additionally there is a 245 page downloadable report even if lucas films standardization was good the out recreation from the original source is off additionally often the theaters them selves were either off or broken in one case a theater had blown drivers being the sound system what started this investigation was the interviewee started to notice that at every premiere some one came in and tweak the sound system so he thought that this was odd if there is supposed to be a standard sound and everything had been set why was there constant adjustment so much like navigation with out correction a small error cause a catastrophe
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post #12 of 13 Old 01-03-2015, 06:56 AM
 
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Originally Posted by drwho2012 View Post
lucas standardized equipment and how sound was supposed to be recreated
The THX sound system had internal standards, but was not an "industry standard". It was optional, and voluntary. That's not what a standard is. Dolby, on the other hand, set criteria for standards in optical stereo soundtracks, 4 channel surround, noise reduction, B-chain equalization and reference SPL. Some of those criteria were adopted ast SMPTE standards. Tomlinson Holman then developed the THX criteria to which improved upon the capabilities of the theater sound system but did not change existing standards, including the target X-curve introduced by Dolby. The THX sound system addressed high frequency coverage, adequate bass extension and SPL capability, the crossover required to do that, theater acoustics and ambient noise, etc. Yes, they sound better than the typical theater, no THX didn't establish or change industry standards.
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but up lintel just recently the whole approach was off as to the how the sound was created in the first place was of there was a podcast on this subject
Production standards have not changed, and were not wrong. The podcast pointed out the sorry state of theater sound, but that has not changed in decades, and THX has had nothing to do with it. Blow speakers have been fairly common in theaters for 40 years. The SMPTE members in the podcast were primarily complaining about the existence of the X-curve, but their complaints about it reflected their complete misunderstanding of what the X-curve is and does. They advocate eliminating it, but that's impossible in today's theaters without blowing every HF driver in every theater, and would not improve anything.
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additionally there is a 245 page downloadable report
The number of pages in a document has nothing to do with its accuracy. Most of those pages are collected data, the problem is with the conclusions.
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Originally Posted by drwho2012 View Post
even if lucas films standardization was good the out recreation from the original source is off additionally often the theaters them selves were either off or broken in one case a theater had blown drivers being the sound system
This is not a problem with any industry standards, it's a theater maintenance and design problem. It always has been. Theaters don't think of sound systems as requiring any routine maintenance, and since that's an expense, they don't do it. Additionally, achieving THX certification is very expensive, partially because of the quality of the equipment required, mostly because to make a theater quiet and free of bleed from other theaters and HVAC noise takes expensive construction. Theaters have not see that improving their sound improves their ticket sales, and that's really why theater sound often is bad.
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Originally Posted by drwho2012 View Post
what started this investigation was the interviewee started to notice that at every premiere some one came in and tweak the sound system so he thought that this was odd if there is supposed to be a standard sound and everything had been set why was there constant adjustment so much like navigation with out correction a small error cause a catastrophe
Exactly, but again, the problem is procedural. If theaters paid a qualified technician to set the theater to match industry standards, and it was a THX which would show a commitment to quality sound, then after calibration the system should be locked, and no one else should be allowed to make adjustments. If the system were properly calibrated in the first place, there would be no need.

I realize the podcast was alarming to many. That was it's intension. However, both podcasts and the conclusions in the 250+ page paper have been largely dismissed by the industry as impractical and not based on a complete understanding of the problem. Yes, the found a lot of theaters that didn't match the standards. That's not a problem with the standards, it's a problem with the theaters just not caring enough to spend what it takes to get it right. One of the paper's fundamental conclusions is that the X-curve is at fault. The X-curve may not be precisely correct, but the error are tiny compared to theater's lack of compliance to it. As a standard, if theaters were properly equalized to that curve, theaters would sound much more consistently like the the dubbing stage. The data in the paper showed that the measured theaters simply don't equalize properly, or permit unqualified individuals to change their theater EQ based on random opinions.
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I 100% agree drwho2012 please use "proper" grammar on this forum.

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Note to drwho2012: In 2015 we still are forced to end each sentence with a period (.) and begin each sentence with an upper-case letter. I know it's hard for a time lord to keep up with all the different customs, just thought you'd like to know how to get your posts to fit in better in this time. It helps them to be more easily understood by us less advanced beings.
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Originally Posted by drwho2012 View Post
lucas standardized equipment and how sound was supposed to be recreated but up lintel just recently the whole approach was off as to the how the sound was created in the first place was of there was a podcast on this subject additionally there is a 245 page downloadable report even if lucas films standardization was good the out recreation from the original source is off additionally often the theaters them selves were either off or broken in one case a theater had blown drivers being the sound system what started this investigation was the interviewee started to notice that at every premiere some one came in and tweak the sound system so he thought that this was odd if there is supposed to be a standard sound and everything had been set why was there constant adjustment so much like navigation with out correction a small error cause a catastrophe
There is not much out there on THX home efforts, except this 10+ year old - September 09, 2004 -web page
http://www.audioholics.com/trade-sho...heater-program
Quote:
The THX Certified Home Theater specifications will include strict guidelines for room layout and design, acoustics, lighting, background noise, and equipment positioning and installation. To roll out this new initiative, THX will be partnering with the nation's leading system integrators and custom designers, as well as its manufacturing partners in the consumer electronics industry.
The THX Ceritifed Home Theater program...
  • Applies to dedicated home theaters only
  • Is best suited for new construction (not a limiting factor, however)
  • is available only to THX qualified designer/installer companies
  • Requires the use of THX Certified or approved products
  • Requires design review and approval by the THX Design office
  • Requires measured proof of audio and video performance using THX specified measurement techniques
  • Does not specify theater size or visual appearance except if they adversely affect THX performance standards.
Qualified Designer/Installer Companies...
  • Are selected based on a completed application and interview
  • Have a solid portfolio of completed dedicated home theater projects
  • Havecertification from THX, CEDIA, HAA, ISF, AIA, NHIA and other relevant organizations
  • Show proof of legal and financial responsibility
THX Provides...
  • Marketing materials for builders and prospective clients
  • Extensive online and offline promotions and advertising
  • A THX Certified Home Theater wall plaque and demonstration material for the client
  • Designer referral and system design services
THX Standards
Picture:
  • 16:9 > =36 degree horizontal viewing angle
  • native HD capable
  • Screen luminance > = 16ft lamberts
  • THX certified, acoustically transparent screen
Sound
  • Mid-band reverberant field pink noise < +/-4dBC between any two seating positions
  • No audible distortion playing program material at 115dBC
  • Background noise < =NC22
  • At least four surround speakers, two side and two back
User Interface
  • Remote controls with a logical user interface
  • All basic functions available with a single key stroke
Measurement
  • Video performance measurements taken using Sencore CP5000 quality gear or better
  • Audio performance measurements taken using four microphone spatial/temporal RTA techniques with 1/12 octave resolution or better.
The new program is almost certainly guaranteed to be a success with all of the high-end home theaters being built around the country (and the world for that matter). This is an idea and concept that has been long in the making (and was highly requested in the past). It's great to see THX expand into the home theater market in this way and add a whole new dimension to their line of certifications.
other
http://www.audioholics.com/audio-tec...eral-questions

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