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Discussion Starter · #1 ·
I'm powering a 7.1 home theater system with a Pioneer Elite SC-75. One of the few settings auto MCACC doesn't change is the crossover for LFE to the sub.

I'm looking for advice on a good starting point for the crossover, as I tweak other things. By default, Pioneer chooses the THX standard of 80Hz. Here are the specs for my speakers, which are all from the same product line.


2 Surrounds and 2 Surround Back

Freq. Response (-3dB): 75Hz-20kHz

Sizes: 3/4", 4"


1 Center

Freq. Response (-3dB): 75Hz-20kHz

Sizes: 3/4", 4", 5.25"


2 Fronts

Freq. Response (-3dB): 36Hz-20kHz

Sizes: 3/4", 4", 8"


1 Sub

Freq. Response (-3dB): 25Hz-150Hz

Size: 12"


I currently have the 7 speakers set to "small" in MCACC. Again, I'm not looking for a definitive answer, just suggestions for a starting point or general criticisms/advice.
 

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Your front speakers go down to 36 hz, and you set them to "small"??....ROFL. THEY should be the main source of your mid-bass, not the MONAURAL source of the subwoofer. That THX 80 Hz default setting for the sub is bullsnort, and is not what you want with large front speakers.


1) You should set your subwoofer to operate only below 40 or 50 Hz. It should NOT operate any higher. Connect it not to the receiver, but the front speakers.


2) Your main speakers should be set to operate full-range. There should be no limits on their operation. Their natural low-frequency rolloff is self-limiting.


3) The surrounds and center are OK operating from 75 hz up.


Actually, I would just totally defeat the receiver settings and let everything run full-range. The smaller speakers will simply roll off naturally at lower frequencies, as they become less sensitive, and there is no reason at all to keep the lower frequencies from them. They simply are not responsive to those frequencies.


Only the subwoofer needs to be limited, by its own low-pass filter.
 

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Quote:
Originally Posted by commsysman  /t/1524826/crossover-setting-suggestions#post_24544173


Your front speaker go down to 36 hz, and you set them to "small"??....ROFL. THEY should be the main source of your mid-bass, not the MONAURAL source of the subwoofer. That THX default setting for the sub is bullsnort.

Since everything below about 100Hz is omnidirectional it is best to have frequencies played by the speakers BEST able to do so and from the location in your room that creates the best FR throughout the listening area.


The people at THX who have a bit of an understanding of movies have determined that 80Hz is appropriate. Most people on this site have found the same to be true in their own systems.

Quote:
1) You should set your subwoofer to operate only below 40 or 50 Hz. It should NOT operate any higher. Connect it not to the receiver, but the speakers. Set the rollof filter ON the subwoofer to 40 or 50 hz. Its job is to take over from the main speakers below thier lower limit. That is ALL it should be doing.

This is of course wrong.


The subwoofer should play everything that you are not sending to your other speakers.


80Hz is a good choice for your general crossover - if you followed the above advice then everything between 40Hz and 80Hz on all channels set to small would be lost.


Let the AVR do the crossover and just set the sub to its highest value.

Quote:
2) Your main speakers should be set to operate full-range. There should be no limits on their operation.

Although your mains are able to play quite low, the subwoofer can play everything below 60Hz better than they can. And if they are not playing these then both the amp and the woofers will be relived from these demanding frequencies.


Not to mention, that in most rooms, the ideal location for low frequency content is NOT the same location as your mains.


You should consider 80Hz as well for your mains, but you may find you prefer a setting at about 60Hz.


You should experiment to see what you prefer, and what integrates best with your sub.


Note that commsysman is not alone in his feeling that mains should run uninhibited. Again, you should experiment and see what sounds best in your environment.

Quote:
3) The surrounds and center are OK operating from 75 hz up.

80Hz is a good number for them, any higher and you risk sending directional frequencies to the sub.
 

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Quote:
Originally Posted by rick240  /t/1524826/crossover-setting-suggestions#post_24544224



80Hz is a good choice for your general crossover - if you followed the above advice then everything between 40Hz and 80Hz on all channels set to small would be lost.


Note that commsysman is not alone in his feeling that mains should run uninhibited. Again, you should experiment and see what sounds best in your environment.


/quote]



How is "everything between 40 and 80 hz" going to be lost, when the front speakers are operating between 40 and 80 hz?


That makes no sense at all. The front speakers are where those frequencies should come from.
 

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Quote:
Originally Posted by commsysman  /t/1524826/crossover-setting-suggestions#post_24544239

Quote:
Originally Posted by rick240  /t/1524826/crossover-setting-suggestions#post_24544224



80Hz is a good choice for your general crossover - if you followed the above advice then everything between 40Hz and 80Hz on all channels set to small would be lost.


Note that commsysman is not alone in his feeling that mains should run uninhibited. Again, you should experiment and see what sounds best in your environment.


How is "everything between 40 and 80 hz" going to be lost, when the front speakers are operating between 40 and 80 hz?


That makes no sense at all. The front speakers are where those frequencies should come from.

everything between 40 and 80Hz ... on all channels set to small


since those frequencies are omnidirectional, and the subwoofer plays them best - they should come from the subwoofer


You are entitled to your opinion, and to share it. I am entitled to disagree, and share that opinion.


PS Apologies for the derisive comment - I removed it.
 

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Discussion Starter · #7 ·
Thanks for the thoughtful advice. I appreciate the time both of you put into your answers. Delving more into the manual for my receiver, I find that I have three options.


1)

Set crossover to X and set all speakers to "small".

Result: All frequencies below X are routed to the sub instead.


2)

Set crossover to X, set front speakers to "big" and the others to "small".

Result: All frequencies below X which would have gone to the others are routed to the sub instead. The fronts continue to receive the full range.


3)

Set crossover to X, set front speakers to "big", set the others to "small", and set the sub to "plus".

Result: All frequencies below X which would have gone to the others are routed to the sub instead. The fronts continue to receive the full range. The sub also receives frequencies below X that go to the fronts.


I guess there's some disagreement on what X should be. From your answers and those in other threads, I find suggestions ranging from 50-120Hz. I also find people suggesting (and arguing over) the first two options Considering the options above, which would you choose for my setup? Would you try the same starting value of X for all three configurations, or would you go lower with the first one?
 

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Unfortunately your AVR only has a single crossover setting - so you can't choose different values for the different speakers.


Also, the only person who can decide which of these will sound best to you in your environment is you.


So try all three - I suggest 80Hz; much higher and sounds from the sub will start being directional.
 

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You can try different crossover points, from 80hz down to 50hz. The higher the x point is, the likely to get directional frequencies from the sub, too low, then you can fully take advantage of the sub. Keep in

mine, with different xover points, you need to adjust your speaker distance, as different frquecies will change the phase between the front and your sub.
 

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Quote:
Originally Posted by daveizdum  /t/1524826/crossover-setting-suggestions#post_24544119


.................the crossover for LFE to the sub.

If the setting you are describing is simply the LFE low-pass setting, then this setting is a low-pass filter that is ONLY applied to the LFE channel info and nothing else. The "crossover" settings that are applied to the speaker channels and subwoofer are a completely different set of settings and their bass management is completely separate. If that's not what you meant by "crossover for LFE to the sub", then ignore the rest of this post.


The LFE channel can contain info as high as 120Hz. In most cases setting the LFE low-pass to 120Hz is fine and many AVRs default to this setting. However, some AVRs do default this LFE low-pass setting to 80Hz. "Why?" is not exactly clear although there are some here who DO advocate setting it to 80Hz on AVRs that default the LFE low-pass to 120Hz. There has been some discussion of this and the "why?" in threads here in the past. You may want to search for these.
 

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Quote:
Originally Posted by daveizdum  /t/1524826/crossover-setting-suggestions/0_100#post_24544119


I'm powering a 7.1 home theater system with a Pioneer Elite SC-75. One of the few settings auto MCACC doesn't change is the crossover for LFE to the sub.

I'm looking for advice on a good starting point for the crossover, as I tweak other things. By default, Pioneer chooses the THX standard of 80Hz. Here are the specs for my speakers, which are all from the same product line.


2 Surrounds and 2 Surround Back

Freq. Response (-3dB): 75Hz-20kHz

Sizes: 3/4", 4"


1 Center

Freq. Response (-3dB): 75Hz-20kHz

Sizes: 3/4", 4", 5.25"


2 Fronts

Freq. Response (-3dB): 36Hz-20kHz

Sizes: 3/4", 4", 8"


1 Sub

Freq. Response (-3dB): 25Hz-150Hz

Size: 12"


I currently have the 7 speakers set to "small" in MCACC. Again, I'm not looking for a definitive answer, just suggestions for a starting point or general criticisms/advice.

In general, you want the crossover for your various channels set above the -3dB of the bass response of the speakers hooked up to those channels. If you have one crossover setting that works for all channels, you should have it above the -3dB point of all of your speakers. In your case, it should be above 75 Hz, since that is the -3dB point of some of your speakers. The reason for this is simple: By the time you are at the -3dB point, your speakers are already on the downward slope to nothingness, and cannot reproduce that frequency as well as those above that point. You want all of the frequencies reproduced for all channels, don't you? If you set it lower, you will have a dip in the response because the speakers are dropping off at 75 Hz. And if you use an EQ to boost those frequencies to avoid the dip, you will add distortion and have a more limited maximum volume, because those speakers cannot reproduce those frequencies very well. In your case, you might be able to get away with 80Hz, but that is a bit low for speakers with a -3dB point of 75 Hz. With your speakers, I would certainly not set it any lower than 80 Hz, as you are going to overtax your center speaker and your surround speakers, unless you listen only at low volumes.



Also, as you can see from the frequency response of your subwoofer versus your front right and left speakers, the subwoofer goes lower. You want the bass from those channels that is below 36 Hz, right? That is why they should be set to "small" and the deep bass redirected to the subwoofer. That way, you get the bass from those channels down to 25 Hz (in your case), before it is dropping off. [Of course, this is all neglecting room affects on the frequency response, but regardless of them, the principle is still the same: The main speakers drop off sooner than the subwoofer, so if you want as much of the bass as possible from the front right and left channels, you will direct it to the subwoofer.]



Your situation shows a reason why I recommend that people buy bookshelf speakers all around: If you set your crossover to 80 Hz (or higher), which is what will give you the best sound with what you have, you will have paid for bass capability in your main speakers that you are not using. There really is no point in spending extra for speakers that can go really deep when one is going to use a decent subwoofer. This, of course, is assuming that one sets things up properly, which many people do not.
 

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Quote:
Originally Posted by daveizdum  /t/1524826/crossover-setting-suggestions#post_24547277


I guess there's some disagreement on what X should be. From your answers and those in other threads, I find suggestions ranging from 50-120Hz. I also find people suggesting (and arguing over) the first two options Considering the options above, which would you choose for my setup? Would you try the same starting value of X for all three configurations, or would you go lower with the first one?

Partially, this depends on your subwoofer and the quality of bass it produces relative to your speakers, which is also partially dependent on the location of the speakers and sub.


I recommend using 80hz for a while with all the speakers set to small--until you get really comfortable with how your setup sounds. Then try experimenting with say 50 or 60hz. See which you like better. And for your surrounds and center, start with 80hz, but then try 100hz later on.


But I would ignore the suggestion to set your towers to large. This will typically route the LFE channel, the .1 in 5.1, to your main speakers. The LFE channel is meant to be reproduced by a subwoofer. Plus, speakers invariably have more distortion below their tuning point. If you have a decent sub, it should almost definitely be better at producing the lowest frequencies that your speakers can produce as it is designed to handle a deeper range of output.


What are the make/model of your speakers and subs? Did I miss that?
 

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Quote:
Originally Posted by cel4145  /t/1524826/crossover-setting-suggestions#post_24548210


But I would ignore the suggestion to set your towers to large. This will typically route the LFE channel, the .1 in 5.1, to your main speakers.



If configured as having a subwoofer connected, the LFE channel info will be sent to the subwoofer and the subwoofer ONLY. You know that.


 
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