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Over the years there has been a lot of debate over which speaker settings should be used with MCACC on Pioneer Receivers..
Pioneer (and some Audiophiles) have always recommended setting ALL speakers to SMALL..Crossover to 80Hz. and Subwoofer to YES..Of course there can be variations in the xover setting, which is dependent on the room and speaker requirements.

If one selects THX in the speaker settings, then the xover is automatically set to 80Hz..

For the most part..these are the settings that most people use..myself included..

The SMALL setting for the speakers is not determined by the physical size of the speakers, but relates to the frequency range that is handled by the front and surround speakers..
When the SMALL setting is selected, frequencies below 80Hz.(if that's the xover point used) are directed to the SW to ease the bass load on the front speakers..thereby improving the quality of reproduction from the front speakers.
This is their reasoning for using these settings...and it sounds quite logical..

The other side of the debate is that you don't need to use the SMALL setting, particularly if you have floor-standers for your fronts, because the bass drivers are quite capable of handling the lower frequencies at high volume levels and peaks without stress...There are even a number of small speakers these days, that are quite capable of handling low bass frequencies without difficulty..

My feeling is that the reason Pioneer in making their recommendations, are trying to cover all aspects of speaker performance within a wide range of speaker quality..

Individual owners of Pionneer AVR's who have used settings other than those recommended, have said that they prefer the sound performance of the settings they have made..Namely, changing the speaker setting from SMALL to LARGE..
Changing the SW setting from YES to PLUS allows lower bass frequencies ( below the xover cut off point) to be handled by both the fronts and the sub,,In some ways, it's actually providing more emphasis to the bass, particularly upper bass which is generally produced more by the LCR speakers than the sub..

One thing that I've found annoying at times is the lack of power and dynamics of orchestral theme music, played during the movie in both DVD's and Blu-rays..
This is certainly not the case with some movies..In particular the opening Star Wars theme and some other well known movies.
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I watch a lot of Sci-Fi and Action/ Adventure type movies, where there's always dramatic theme music and similar dynamic music played through the movie..
On occasions, that music sounds a bit "thin"..lacking body and oomph! when it is obvious that the movie at that point requires full bodied dynamic sound..
I've always put it down to post-production control variations between different studio's, but of late I started to question whether my audio system was performing at it's best..Namely my MCACC settings..

I have always been an advocate of following the recommended settings..ALL SMALL..Xover 80Hz. SW..YES..So I decided to bite the bullet and try some other settings..

I set the fronts to LARGE..Surrounds I left at SMALL and left xover at 80Hz..and set the SW to PLUS..I left the calibration for that pre-set as it was previously done..

I first switched on HDTV and immediately noticed that male voices sounded "fuller".. for want of a better word..I certainly couldn't tell if there were any other improvements because of their highly compressed audio signal..

I then put in a Blu-ray movie to get a better idea of any further improvements..I played "The Prince of Persia"..This is one movie where I felt that the orchestral theme was a bit thin..and was the type of music and movie that really needed some power and dynamics..I mean it sounded alright, but just lacked something..
Well, the opening theme blew me away this time!! It was full and enveloping for the first time..just like I expected it should sound.. with very clear drum beats and the individual instruments coming through strongly..What you might call full bodied!..and all through the movie the music sounded richer..

I then decided to play a Star Wars movie, wondering if that theme music would show any improvement..It did!!
Again..that music had even more body to it than I had ever heard before!

I've now played a number of my movies and have noticed significant improvements in some, while others just seem slightly better..for what ever reason..

I'm sure there are some audio systems which may perform better on the recommended settings, but if you feel that there is something lacking with your current MCACC settings, then I strongly urge you to try some other settings..You may be surprised at the results..
 

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The audible perception you’re talking about is highly dependent on the particular speakers (small vs. large) and the room (ditto).

For instance, I see your Behringer speakers advertise bass extension down to only 75 Hz. So I can see how running them full-range might help things sound fuller, as stacking a 24 dB/octave filter on top of, and at roughly the same frequency as, their natural acoustic roll-out could indeed make them sound “thin” and insubstantial.

However, the same speakers in a smaller room would generate greater perceived bass response and might sound “full” even with a “small” setting.

Conversely, if instead of the Behringers you had speakers with more prodigious bass output and/or extension, they would likely sound “full” enough even set to “small.” The crossover frequency and slope is merely an electrical signal. The functioning frequency and slope can easily be acoustically modified or skewed by the speakers capabilities, the room, or both.

So when people weigh in on the MCACC debate, it would be good to get an idea of the capability of their speakers compared to the size of their room (cubic ft., including any areas that the listening room opens up to). I’m going to hazard an educated guess that the fans of “mains set to large” are mostly folks with smaller speakers and/or larger rooms, and more-or-less the reverse for the fans of “mains set to small” position. This is similar to the full-range house curve I discussed in my house curve article, if not essentially the same thing.

The point is, it’s nice that you’ve found that setting your mains to large got you an improvement, but if you ever change your speakers, or move the system to a different room, you’ll probably need to re-evaluate things.

Regards,
Wayne
 

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I agree that it likely has to do more with the combination of room and speaker natural rolloff vs. any ideal crossover frequency. Even THX certifies differently for different rooms. Have you tried actually raising the crossover point? If the additional attenuation beginning around 80Hz thins the sound (which is already combined from the sub and mains meaning that is also the low pass point for your sub) the improvement might work in the opposite direction--letting the sub carry more bass/mid-bass frequencies--as well and theoretically ease the burden on the 6.5" driver enough to clarify the mids.
 

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It's important to remember that the receiver's amps play a large part in this as well. By having the crossover at 80Hz or the speakers set to 'small' you are reducing the load that the amps have to carry on those channels. This will give more overhead to the 81Hz and above range while the amp on the sub carries 80Hz and below. Most low end and mid-range receivers will struggle pushing the power to larger speakers or 4 ohm loads like my Axiom M80's and VP180. Even the new SC-57 that I reviewed earlier this month struggled when compared to the stand alone power amps.
 

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Discussion Starter #5
For instance, I see your Behringer speakers advertise bass extension down to only 75 Hz. So I can see how running them full-range might help things sound fuller, as stacking a 24 dB/octave filter on top of, and at roughly the same frequency as, their natural acoustic roll-out could indeed make them sound “thin” and insubstantial.
I have been under the impression that those speakers went down to 55Hz..I checked the specs. last night and they do indeed only extend to 75Hz..It's the 2031p speakers that go down to 55Hz..the ones I had originally intended to buy..
So what you say may well be right..
After seeing that they only went down to 75Hz..I realised that an 80Hz. xover to the sub, would be to low..so I raised the xover to 100Hz..The result of this seemed to produce a smoother transition between fronts and sub..
However, the same speakers in a smaller room would generate greater perceived bass response and might sound “full” even with a “small” setting.
I would classify my room as small..
The Behringers have always sounded "good"..but not excellent..so in my case the SMALL setting was not the best..

So when people weigh in on the MCACC debate, it would be good to get an idea of the capability of their speakers compared to the size of their room (cubic ft., including any areas that the listening room opens up to). I’m going to hazard an educated guess that the fans of “mains set to large” are mostly folks with smaller speakers and/or larger rooms, and more-or-less the reverse for the fans of “mains set to small” position. This is similar to the full-range house curve I discussed in my house curve article, if not essentially the same thing.
That may very well be the case..I can't recall off hand whether advocates of the LARGE setting were mainly using small speakers, but quite possibly..I do know of at least one who was using floorstanders, but again that doesn't always mean they have good bass extension..
 

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Discussion Starter #6
Have you tried actually raising the crossover point?
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When I first bought AVR..I did have the crossover set at 100Hz..At that time I preferred the sound when set to 80Hz.but it was in early days of understanding how MCACC worked..
After reading that the recommendation for the xover point was 80Hz. I left it at that!

As mentioned in the post above..I've now set the xover to 100Hz. with further improvement..
Thinking about it..I should now probably try that xover with the speakers set to SMALL and compare the two..particularly now that I have MCACC much more finely tuned than when I first set it up!
 

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For instance, I see your Behringer speakers advertise bass extension down to only 75 Hz. So I can see how running them full-range might help things sound fuller, as stacking a 24 dB/octave filter on top of, and at roughly the same frequency as, their natural acoustic roll-out could indeed make them sound “thin” and insubstantial.


Please correct me if I am wrong. Is the THX HPF (80Hz and up) not a 12dB/oct slope? Is the design not to work with the acoustic roll-off of THX speakers at 80Hz (typically 12dB/oct for sealed box) to become a 24dB slope?

However, the same speakers in a smaller room would generate greater perceived bass response and might sound “full” even with a “small” setting.
Prof's room (like my own) is small. I am not sure how the difference between 80Hz (HPF'd) and a natural acoustic roll off is so night and day. I wonder if Prof experimented with lowering the crossover from the THX 80Hz default back to 50Hz, rather than bi-pass HPF'ing altogether?

The idea of running full range + sub is OK if the LCRs can actually run "full range" (though even a friend's $7K flag ship VAF Research speakers can not run flat to 20Hz and why he uses HPF'ing). If they did, you would get a 6dB acoustic gain. In this case (no I've heard the actual system) Prof could not be getting that gain because his speakers roll off at 75Hz. That means 20~75 is not being heard from the LCRs. Wasted energy IMO. Tom Holman added subwoofers to the THX audio system so that the sound mixers could actually hear the low bass when mixing film sound. The natural rolloff of a cinema system in a baffle wall is about 40Hz. And the question of how important is that octave 20~40Hz became a concern because he could hear that on his own system at home and not in the dubbing stage. And we are talking almost 2 octaves here :scratch:

The way I see this is no difference to bi-amping a tower speaker without the use of an active crossover and relying on the internal passive filtering of the speakers.

Bi-amping with passive filters and you have -
1. Amp 1 sends 20~20K and the passive LPF uses 20~3K with everything above 3K being wasted.
2. Amp 2 send 20~ 20K and the passive HPF uses 3K~20K with everything below 3K being wasted.

Add an active crossover and you knnow have -
1. Amp 1 sends 20~3K powering the woofer.
2. Amp 2 send 3K~ 20K powering the tweeter.

There is possibly some in-band gain and no power wastage.

In Prof's case, the AVR is sending 20~20K, but the speaker only plays 75~20K. The SW gets 20~80 + LFE, so there is a slight double at at 75~80Hz, but no real gain.

Just my 2 cents worth.
 

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I know for myself Ive re run Audyssey several times as I have made changes and every time it sets all my speakers to full range. Ive always re adjusted them to 40Hz and find that is the magic number that makes everything sound good. All of my speakers can do 40Hz (except my centre) with ease and as I am running my mains off an external amp this never seems to cause issues.
Ive also tried the 80Hz settings and also find it "thin" sounding.
 

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Discussion Starter #9
It's important to remember that the receiver's amps play a large part in this as well. By having the crossover at 80Hz or the speakers set to 'small' you are reducing the load that the amps have to carry on those channels. This will give more overhead to the 81Hz and above range while the amp on the sub carries 80Hz and below. Most low end and mid-range receivers will struggle pushing the power to larger speakers or 4 ohm loads like my Axiom M80's and VP180. Even the new SC-57 that I reviewed earlier this month struggled when compared to the stand alone power amps.
That's a good point Dale..Giving more overhead to the receiver would certainly help with high levels and peaks..
But I have to say that I've never experienced any overload conditions or excessive distortions, regardless of the xover point..and I play my movies pretty loud!
In fact my room is quite "dead" acoustically speaking.. so much so that all my speaker levels are in the +dB. range (Fronts at +4.0dB and surrounds at +6.0dB!) when set at 75dB..Admittedly my surrounds are very inefficient speakers! :R..
 

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Ive also tried the 80Hz settings and also find it "thin" sounding.
Then might suggest that there is a level mismatch. The idea of adding a Sub-woofer is to extend the frequency response of the main woofer. As a result, it takes the load of the main woofer and allows it to play cleaner - less distortion, greater dynamic range and with a wider frequency response. If you measure your LCR levels to +75dB, what level are you setting the SW to?
 

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I set my PB13u to 85db, I like it a bit hotter.
 

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lol, I like my bass :) Thats probably why my sub bottomed out during transformers DOTM :whistling:
 

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lol, I like my bass :) Thats probably why my sub bottomed out during transformers DOTM :whistling:
Go play WAR OF THE WORLDS and see if you launch it. I can't believe all those guys on A that claimed they blew up their SVS subs with that film.
 

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Please correct me if I am wrong. Is the THX HPF (80Hz and up) not a 12dB/oct slope? Is the design not to work with the acoustic roll-off of THX speakers at 80Hz (typically 12dB/oct for sealed box) to become a 24dB slope?
I agree with you. While I don't have a Pioneer or even a THX receiver, mine was clearly built with a 24db/oct low pass on the sub but a 12db/oct high pass on the rest of the SMALL speakers that were designed to go with the receiver. I also believe this is the intent with THX settings.

I now have Klipsch RF-82 mains that I've measured response to 40 Hz (-6db or so) in my large room. I'm setting the speakers to small because, when set to large, it's difficult to eq a smooth LF response in room. (I only have eq on sub channel).

Because the speakers extend lower than intended with this receiver, I still get quite a bit of extension out of the mains on a 12dB/oct crossover.

If you have speakers with less low end extension, I could see how you might prefer the lower effective crossover slope with mains set to Large and natural speaker roll-off. A little effective eq bump in mid bass perhaps...

-V
 

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The idea of running full range + sub is OK if the LCRs can actually run "full range" (though even a friend's $7K flag ship VAF Research speakers can not run flat to 20Hz and why he uses HPF'ing). If they did, you would get a 6dB acoustic gain. In this case (no I've heard the actual system) Prof could not be getting that gain because his speakers roll off at 75Hz. That means 20~75 is not being heard from the LCRs. Wasted energy IMO.
I disagree with you here. 12dB/Oct roll off at 75Hz does not mean that 20-75 Hz is not being heard from the mains. There is still appreciable energy below 75Hz that will be played through these speakers. I've measured it myself on my own speakers.
 

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My Pioneer VSX23TXH has additional frequency shaping capability which I use depending on the mains that I use. I make changes to the EQ while in the MCACC setup particularly in the area of the SW crossover. In addition after MCACC has been completed I make pluses and minuses using the "tone" controls ie: bass treble + plus or - minus 6, settings. The frequency adjustments with the Pioneer receiver are almost limitless . . . . below 63Hz.
 

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Go play WAR OF THE WORLDS and see if you launch it. I can't believe all those guys on A that claimed they blew up their SVS subs with that film.
Hmmm, Ive watched it twice and it did not bottom out. Super 8 is another film that got very close.
 
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