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Post by bluescale on Sept 5, 2014 1:36:18 GMT -5
]LR filters sum flat at the crossover point with each side low/hi having the same phase. -6dB + -6dB = .5 + .5 = 1 BW filters sum with a 3 dB bump at the crossover point and aren't in phase. -3db + -3dB = .707 + .707 = 1.414 Okay, I get the part about the 3 dB bump at the crossover. I'm not sure I understand the part about phase. Is that what the decimal part of the equation above is referencing? When I set the distance for my sub, I did so by running a test tone at the crossover frequency, and adjusting it until I got the highest frequency response. Are you saying that when I did that, I wasn't really making sure they were in phase? If BW filters lead to speakers and sub(s) being out of phase, is there ever an application where they make sense? Is this a legitimate design choice on Emotiva's part, or a mistake? Are my rapid fire questions getting annoying? |
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Post by Chuck Elliot on Sept 5, 2014 2:17:22 GMT -5
]LR filters sum flat at the crossover point with each side low/hi having the same phase. -6dB + -6dB = .5 + .5 = 1 BW filters sum with a 3 dB bump at the crossover point and aren't in phase. -3db + -3dB = .707 + .707 = 1.414 Okay, I get the part about the 3 dB bump at the crossover. I'm not sure I understand the part about phase. Is that what the decimal part of the equation above is referencing? When I set the distance for my sub, I did so by running a test tone at the crossover frequency, and adjusting it until I got the highest frequency response. Are you saying that when I did that, I wasn't really making sure they were in phase? If BW filters lead to speakers and sub(s) being out of phase, is there ever an application where they make sense? Is this a legitimate design choice on Emotiva's part, or a mistake? Are my rapid fire questions getting annoying? I've give you a fuller explanation tomorrow, but for now neither what you did or Emotiva is in error. With Emotiva I just wonder why the crossover point seems to drift and would love to hear from them! |
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Post by igorzep on Sept 5, 2014 2:27:22 GMT -5
Can you explain the practical differences between the two? What makes Linkwitz–Riley crossovers superior to Butterworth? Like I said, I'm still learning about this stuff  . An article with good graphical explanation. |
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Post by igorzep on Sept 5, 2014 2:38:24 GMT -5
I also would like to know why these all appear to be Butterworth filters and not LR? All 12dB/octave ones, but not 24db/octave ones. Obviously they are Butterworth because when cascaded with another 12dB/octave Butterworth they will become LR4. They are assuming this cascading will happen (same as with THX). They are not for gentler crossovers as most unaware audiophiles would think and use it for Sure, I would like to see clear explanation in the manual too, as this would explain a lot of basic questions before they even asked, allowing to discuss more complicated and interesting topics... |
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Post by igorzep on Sept 5, 2014 2:45:41 GMT -5
With Emotiva I just wonder why the crossover point seems to drift and would love to hear from them! Look @ the 80Hz/12dB graph. If you level-align them the crossover will be dead on 80Hz. The small misalignment is because of the level. The mis-alignment in 24/12dB graphs is because 24dB slope is LR4, and 12dB slope is Butterworth, when you cascade it with another Butterworts at the same frequency (possible low-pass in the sub/natural roll-off in the satellite) it will end up with the complimentary LR4 curve. |
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Post by bluescale on Sept 5, 2014 4:01:27 GMT -5
With Emotiva I just wonder why the crossover point seems to drift and would love to hear from them! Look @ the 80Hz/12dB graph. If you level-align them the crossover will be dead on 80Hz. The small misalignment is because of the level. The mis-alignment in 24/12dB graphs is because 24dB slope is LR4, and 12dB slope is Butterworth, when you cascade it with another Butterworts at the same frequency (possible low-pass in the sub/natural roll-off in the satellite) it will end up with the complimentary LR4 curve. So is your suggestion that one should try a 12dB slope first rather than 24dB? |
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Post by bluescale on Sept 5, 2014 4:02:19 GMT -5
Can you explain the practical differences between the two? What makes Linkwitz–Riley crossovers superior to Butterworth? Like I said, I'm still learning about this stuff . An article with good graphical explanation. I was also just linked this article as well. www.rane.com/note160.html |
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Post by igorzep on Sept 5, 2014 4:37:07 GMT -5
So is your suggestion that one should try a 12dB slope first rather than 24dB? My suggestion is to always use 24dB roll-off for sub except the case if the sub have it's own LPF that cannot be turned off. And as the mains are always getting 12dB HPF roll-off, they should be crossed over close to the natural roll-off of the speaker (it's F3). Or, if you are setting it significantly higher - just target the response with corresponding roll-of by means of PEQ or Dirac target curve editor (actually always equalize every speaker to that target). |
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Post by urwi on Sept 7, 2014 14:22:02 GMT -5
My suggestion would be to measure the in room response and choose what works best. The discussion about how certain electrical filters sum is helpful in understanding how filters sum but it is pretty much useless when it comes to choosing the correct settings for the subwoofer-satellite splice. I would be far more helpful if bass management would offer a very wide variety of crossover slopes and independent cutoff frequencies for each speaker channel. Currently the cutoff for low and high pass are linked. Look @ the 80Hz/12dB graph. If you level-align them the crossover will be dead on 80Hz. The small misalignment is because of the level. The mis-alignment in 24/12dB graphs is because 24dB slope is LR4, and 12dB slope is Butterworth, when you cascade it with another Butterworts at the same frequency (possible low-pass in the sub/natural roll-off in the satellite) it will end up with the complimentary LR4 curve. So is your suggestion that one should try a 12dB slope first rather than 24dB? |
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Post by sme on Sept 9, 2014 1:55:10 GMT -5
My suggestion would be to measure the in room response and choose what works best. The discussion about how certain electrical filters sum is helpful in understanding how filters sum but it is pretty much useless when it comes to choosing the correct settings for the subwoofer-satellite splice. I would be far more helpful if bass management would offer a very wide variety of crossover slopes and independent cutoff frequencies for each speaker channel. Currently the cutoff for low and high pass are linked. I totally agree with this, and would add that the room enters the equation in a big way. My current "crossover" configuration consists of: - 24 dB/octave LPF on subs at 120 HZ
- 12 dB/octave HPF on mains at 120 Hz (these two are provided by my Denon AVR's "crossover" choice of 120 Hz.)
- "optimized crossover" filter applied by Audyssey Pro (approximately 12 dB/octave HPF from 80 Hz down)
- socks stuffed in the ports of my front channels *after* the Audyssey run
The reason I added the socks was because, even with the combination of the other filters, my mains were still producing too much bass in the listening area that adversely interferes with my subs well below 80 Hz and particularly at 63 Hz, where my room has a strong resonance. The two subs that handle sound > 50 Hz are placed closer to the listeners and provided a smoother response than the mains do above 80 Hz. I choice 120 Hz crossover for the time as a compromise. Perhaps I will lower it again some day when I have bass absorption installed.
Another thing that needs to be chosen using measurements is the sub delay (aka distance). Note also that the sub delay and crossover are interdependent, so a good sub delay with one crossover may give poor results when used with another crossover. To my knowledge, neither Audyssey nor Dirac are capable of consistently choosing a good sub distance. The optimum delay is not necessarily the delay that time-aligns the impulse response peaks. In fact, the optimum may be ill-defined in many cases. Ultimately it requires considering the combined responses of each mains channel with the sub channel(s) at all the listening locations. There are different ways of weighing these things. My approach is to give more weight to the front stage speakers, particularly the center speaker. I often listen to music using Dolby PLIIx with the channel width set to 2, and since a lot of musical bass is panned dead center, this sends most bass to the channel that plays it best.
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Post by htguy on Sept 21, 2014 22:10:55 GMT -5
Hey guys,
I know you where asking for dual subs to be eq together however some may not want both sub outs to be eq as one. For example if you have a transducer (ie butt kicker or Crowsen) you normally do not want any Eq so one mono sub out can be for that and the other sub out for your single sub where you may want eq. If Emotiva does allow for the two sub outs to be eq together hopefully they make it as an option to the user so one can choose to eq subs together or not.
On a separate note if you are using two subs then why not set up both subs with distance, phase, loudness via two subs out independent memories and then use a separate test signal with something like REW to give you your cuts and boosts and then just apply those same cuts and boost to both sub eq's? Wouldn't that be the same as eq'ing both subs as one?
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Post by bluescale on Sept 21, 2014 22:42:12 GMT -5
On a separate note if you are using two subs then why not set up both subs with distance, phase, loudness via two subs out independent memories and then use a separate test signal with something like REW to give you your cuts and boosts and then just apply those same cuts and boost to both sub eq's? Wouldn't that be the same as eq'ing both subs as one? It would when using the PEQ, but when Dirac is in place, how do you tell it to copy the same EQ settings to both subs? |
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bootman
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Post by bootman on Dec 18, 2014 9:26:27 GMT -5
It is pretty simple. Dual mono with independent level and distance and one combined EQ. If they don't feel that is important, then it should be stated why and also how Dirac will handle the EQ with the current config. I really do hate quoting myself but with Dirac now available and some preliminary results in with those trying to EQ two subs, I now feel it is relevant to jump start this thread. For those who want to start reading after the last firmware update gave the XMC dual mono EQ you can start reading here: emotivalounge.proboards.com/thread/37908/xmc-bass-management?page=8 |
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edrummereasye
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Post by edrummereasye on Dec 18, 2014 12:36:13 GMT -5
It is pretty simple. Dual mono with independent level and distance and one combined EQ. If they don't feel that is important, then it should be stated why and also how Dirac will handle the EQ with the current config. I really do hate quoting myself but with Dirac now available and some preliminary results in with those trying to EQ two subs, I now feel it is relevant to jump start this thread. For those who want to start reading after the last firmware update gave the XMC dual mono EQ you can start reading here: emotivalounge.proboards.com/thread/37908/xmc-bass-management?page=8I believe the "user-defined speaker grouping" in the $99 Dirac upgrade may be the answer... |
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Post by ansat on Dec 18, 2014 12:40:36 GMT -5
I really do hate quoting myself but with Dirac now available and some preliminary results in with those trying to EQ two subs, I now feel it is relevant to jump start this thread. For those who want to start reading after the last firmware update gave the XMC dual mono EQ you can start reading here: emotivalounge.proboards.com/thread/37908/xmc-bass-management?page=8I believe the "user-defined speaker grouping" in the $99 Dirac upgrade may be the answer... Possibly. I think having the ability to add / delay over the top of Dirac could also be a solution. Tony |
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Post by ansat on Dec 18, 2014 12:44:26 GMT -5
Also emotivalounge.proboards.com/thread/39650/xmc-dirac-multi-sub-prepare is relevant to this situation. So for my findings indicate that even if grouping was done, having an array of speakers time aligned perfectly will not result in a good measurement. Currently, I see lots of solutions that could help, but to get things right, I don't see a way to avoid an outboard dsp. Tony |
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tubby
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Post by tubby on Dec 18, 2014 14:12:59 GMT -5
I really do hate quoting myself but with Dirac now available and some preliminary results in with those trying to EQ two subs, I now feel it is relevant to jump start this thread. For those who want to start reading after the last firmware update gave the XMC dual mono EQ you can start reading here: emotivalounge.proboards.com/thread/37908/xmc-bass-management?page=8I believe the "user-defined speaker grouping" in the $99 Dirac upgrade may be the answer... I was thinking that as well but based on the FAQ it sounds like speaker grouping just applies the same target curve to each channel in the group but still treats the channels separately when testing and correcting. |
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edrummereasye
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Post by edrummereasye on Dec 18, 2014 15:44:23 GMT -5
I believe the "user-defined speaker grouping" in the $99 Dirac upgrade may be the answer... I was thinking that as well but based on the FAQ it sounds like speaker grouping just applies the same target curve to each channel in the group but still treats the channels separately when testing and correcting. Ouch. Perhaps not, then... |
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