KeithL
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Post by KeithL on May 3, 2020 14:07:45 GMT -5
A "timing chime" will help you align things... And it is also true that, because of the frequencies involved, the "impulse response" on a subwoofer does not require microsecond measurement accuracy anyway. However, I still prefer measuring the actual combined signal at the listening position, rather than trusting the math to work out right. (There are still too many variables... and, like it or not, you are not combining perfect measurements, taken with precision equipment, in an anechoic chamber.) If you really just want to time align the speakers... at a single frequency... Play a repeating click, like a metronone, from all the channels, in monaural, and adjust everything until you hear a single sharp clean click. Even better, do it first with only your left front and right front channels connected, and adjust those two for a perfect sharp click dead center. Then connect another channel, and adjust it until it lines up perfectly with the other two, and you again have a nice sharp click. Repeat this until all of the channels are playing and you hear a single clean sharp monaural click from all of them. It's even better, and far more precise, if you use some program that lets you see the click on an oscilloscope display. Then you can actually LOOK for a nice sharp click, with minimal ringing or spreading, and no obvious doubling (much like focusing a camera for the sharpest picture).
This is the equivalent of "nulling for errors', and is much simpler, and more precise, than fussing around with graphs and curves.
(Remember that what you're adjusting for is that the sound from all of your speakers arrives at the listening position at the same time - and this is the most precise way to do that.)
I would also point out that, as far as I'm concerned, people are WAY too fussy about things like frequency response... Sit in one spot, nail the microphone stand to the floor, mark all the speaker positions with masking tape, and you can get a very precise reading... And you'd better then be prepared to sit in one of those dentist chair things when you listen to the result...
But then, move something just a few inches, or have the humidity go up a bit, and it's going to be a dB or two different... This is far less of an issue with subs because very low frequencies and long wavelengths are involved... But this sort of fussy precision is still a losing battle...
Consider yourself lucky if you can manage a response that is flat within a few dB over a reasonably large listening area... And if you can get an impulse response that actually looks more or less like it's supposed to, with no major spreading, or flat out multiple peaks... (Or seriously think about headphones...)  Using an impulse test click, or a carefully calibrated chirp or sweep, is a great way for software to gather a lot of useful information, all at once. But it isn't always anywhere near the best way to collect information that a human is going to use to make manual adjustments.
We humans often find a simple test that collects exactly the information we need to be far more precise and simple to use.
Hey Keith thanks for chiming in. I do like your method and will give it a read. How does that method allow for impulse measurements and such? Seems like it would make it very complicated to time align the speakers vs just use ASIO to select the right speaker as it is meant to be used. To clarify I’m using these measurements to verify subwoofer design. Here is an overlay of the hornres and previously measured subwoofers from a different receiver.  This is what I am trying to recreate. Issue is it seems the LFE channel might have a bug. I will do some more digging and see if I can pinpoint exactly what is going on here and report it out to you. Something is Off for sure as I’ve done this so many times I can’t count but can’t get it to work here. REW can be set to play a timing chime at the beginning of every sweep that I think you can use for this. This is one area ive tried to learn more about. |
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Post by megash0n on May 3, 2020 14:16:08 GMT -5
That's an interesting question... and one with many nuances to it.
First off, as far as I recall, REW always measures one channel at a time... This is great for frequency response but more or less useless for combined impulse response from multiple speakers...
Second, even with ASIO, I would not be inclined to trust a computer to deliver multiple channels with precise enough timing for accurate impulse measurements. There are simply too many variables between the software, the ASIO driver, and the output. Superimposing those graphs assumes that you absolutely trust them to start at exactly the same point in time. I would also note that, in a room, your results are only going to be valid at exactly one spot in the room anyway.
Another factor is that, in a processor, there are multiple paths to the subwoofer.
For example, bass from the LFE channel goes straight to the sub, although there is a default low-pass filter in there.
However, with the bass management for the other channels, there are filters involved, each of which WILL introduce some phase shift. And the distance setting then adds to that a fixed time delay.
(Therefore, technically speaking, there will be no single solution that will be absolutely perfect for both LFE and bass managed content...)
The way I see it you have two choices....
Try to tune the impulse response for JUST THE SUBS.... (assuming that, once you get all the subs to act like one ideal sub, you're going to trust the other stuff to be right).
Or try to do so for "the entire system".... (remembering that the adjustment that is perfect for bass managed content my not be equally perfect for LFE content and vice versa). (The FIRST option there would be my choice.... get the subs right and trust the system to handle the details beyond that.)
However, in either situation, I would not even bother to plot separate graphs, and then try to carefully "align" them. There are simply too many variables.... and too many unknowns... and too much opportunity for the theory to not match the practical results.
What I would do is to hook up all the subs... in whatever manner I will be using them...
And play whatever test signal I prefer through all of them at once... (For example, play a test album where someone goes Whack Whack Whack on a drum, or a nice series of impulse clicks....)
Then I would sit the microphone at my listening position... And look at the ACTUAL IMPULSE RESPONSE AT THE LISTENING POSITION WHEN I PLAY THE TEST SIGNAL....
And I would adjust the timing on the subs until it looks good (one peak, or least ringing, or whatever you consider to be the most important goal)....
Doing it this way effectively "eliminates all variables, both known and unknown, and allows you to actually adjust what you will be hearing".
Hey Keith thanks for chiming in. I do like your method and will give it a read. How does that method allow for impulse measurements and such? Seems like it would make it very complicated to time align the speakers vs just use ASIO to select the right speaker as it is meant to be used. To clarify I’m using these measurements to verify subwoofer design. Here is an overlay of the hornres and previously measured subwoofers from a different receiver. This is what I am trying to recreate. Issue is it seems the LFE channel might have a bug. I will do some more digging and see if I can pinpoint exactly what is going on here and report it out to you. Something is Off for sure as I’ve done this so many times I can’t count but can’t get it to work here. For clarity sake, we aren't suggesting to measure multiple speakers at once. Asio just allows you to "pick" Every channel instead of the method you describe of having to swap cables, distance, crossover settings, etc. |
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Post by geebo on May 3, 2020 15:33:39 GMT -5
The 2x4HD can be converted to Dirac 2 for $199 and a firmware upgrade. Thank you for the info, does Dirac 2 incorporate the new bass algorithm that you are aware of? As far as I know it's Dirac 2 only. Not sure if one would be able to purchase the add on bass module or not. |
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Post by megash0n on May 3, 2020 16:17:13 GMT -5
Thank you for the info, does Dirac 2 incorporate the new bass algorithm that you are aware of? As far as I know it's Dirac 2 only. Not sure if one would be able to purchase the add on bass module or not. This is kind of on the same lines as our questions regarding emotiva's platforms. If the Dirac 2.0 engine is the same whether it is the base or 5 different add-ons, then it should not matter. I thought the DDRC-24 was the one that can use Dirac. I assume the 2x4HD can be upgraded to this platform? I didn't dig in, but it looks as if both use the same Sharc processor. Probably just a rebadged it for a higher price. |
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Post by bluescale on May 3, 2020 17:28:58 GMT -5
I'm sure we are just crossing wires because we aren't in a room talking this over. But, an LFE encoded signal is not the same as the LFE channel. The LFE channel could be configured as lfe or mono. In my opinion, you aren't concerned whatsoever in an lfe encoded signal. That should do what it does regardless. When selecting the ASIO driver channel that is directly tied to the center sub, a basic pcm audio sweep from 20hz to 200hz or so should be played. Nothing encoded. If this is the case, and you are still getting a crossover applied, then something is broken or you are actually choosing the wrong channel. In my opinion. Yeah would be much easier in the same room lol. LFE encoded signal sent to the XMC shouldn’t change the REW reading no matter if set to mono or LFE. Bc even in mono the sub still controls the LFE signal. Only difference is in mono it’s being asked to also handle anything below crossover points of speakers. Problem is that’s not how it works here. When set to mono an LFE only signal only plays to the crossover. So for instance let’s say any channel has a crossover of 80. If I then send an LFE only signal to the Xmc2 it applies a crossover at 80. Nothing else should be in play here at all. That’s how ASIO and REW work Can you provide a screenshot of your settings in REW? Unfortunately, my REW laptop is down, so I can't show you how mine was configured, but I'm pretty sure I sent a sweep using HDMI 4 in ASIO, as was able to get this sweep on my XMC-1 (I haven't messed with it on the XMC-2 yet):  This is how you want it to look, right? |
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Post by geebo on May 3, 2020 17:52:05 GMT -5
As far as I know it's Dirac 2 only. Not sure if one would be able to purchase the add on bass module or not. This is kind of on the same lines as our questions regarding emotiva's platforms. If the Dirac 2.0 engine is the same whether it is the base or 5 different add-ons, then it should not matter. I thought the DDRC-24 was the one that can use Dirac. I assume the 2x4HD can be upgraded to this platform? I didn't dig in, but it looks as if both use the same Sharc processor. Probably just a rebadged it for a higher price. Pretty sure the DDRC-24 and the 2x4HD are the same hardware. The first is sold with the Dirac firmware and the latter can be upgraded to the DDRC-24. I think their UMIK-1 is also a requirement to use it with Dirac. www.minidsp.com/products/dirac-series/2x4hd-to-ddrc-24 |
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Post by megash0n on May 3, 2020 18:03:23 GMT -5
Yeah would be much easier in the same room lol. LFE encoded signal sent to the XMC shouldn’t change the REW reading no matter if set to mono or LFE. Bc even in mono the sub still controls the LFE signal. Only difference is in mono it’s being asked to also handle anything below crossover points of speakers. Problem is that’s not how it works here. When set to mono an LFE only signal only plays to the crossover. So for instance let’s say any channel has a crossover of 80. If I then send an LFE only signal to the Xmc2 it applies a crossover at 80. Nothing else should be in play here at all. That’s how ASIO and REW work Can you provide a screenshot of your settings in REW? Unfortunately, my REW laptop is down, so I can't show you how mine was configured, but I'm pretty sure I sent a sweep using HDMI 4 in ASIO, as was able to get this sweep on my XMC-1 (I haven't messed with it on the XMC-2 yet): This is how you want it to look, right? Those are pretty |
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Post by megash0n on May 3, 2020 18:04:48 GMT -5
This is kind of on the same lines as our questions regarding emotiva's platforms. If the Dirac 2.0 engine is the same whether it is the base or 5 different add-ons, then it should not matter. I thought the DDRC-24 was the one that can use Dirac. I assume the 2x4HD can be upgraded to this platform? I didn't dig in, but it looks as if both use the same Sharc processor. Probably just a rebadged it for a higher price. Pretty sure the DDRC-24 and the 2x4HD are the same hardware. The first is sold with the Dirac firmware and the latter can be upgraded to the DDRC-24. I think their UMIK-1 is also a requirement to use it with Dirac. www.minidsp.com/products/dirac-series/2x4hd-to-ddrc-24Makes sense. If I end up having to use minidsp, I'll probably get the bigger one to be able to continue using a balanced connection since my amps like those better. |
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Post by kahodges1721 on May 3, 2020 18:14:27 GMT -5
A "timing chime" will help you align things... And it is also true that, because of the frequencies involved, the "impulse response" on a subwoofer does not require microsecond measurement accuracy anyway. However, I still prefer measuring the actual combined signal at the listening position, rather than trusting the math to work out right. (There are still too many variables... and, like it or not, you are not combining perfect measurements, taken with precision equipment, in an anechoic chamber.) If you really just want to time align the speakers... at a single frequency... Play a repeating click, like a metronone, from all the channels, in monaural, and adjust everything until you hear a single sharp clean click. Even better, do it first with only your left front and right front channels connected, and adjust those two for a perfect sharp click dead center. Then connect another channel, and adjust it until it lines up perfectly with the other two, and you again have a nice sharp click. Repeat this until all of the channels are playing and you hear a single clean sharp monaural click from all of them. It's even better, and far more precise, if you use some program that lets you see the click on an oscilloscope display. Then you can actually LOOK for a nice sharp click, with minimal ringing or spreading, and no obvious doubling (much like focusing a camera for the sharpest picture).
This is the equivalent of "nulling for errors', and is much simpler, and more precise, than fussing around with graphs and curves.
(Remember that what you're adjusting for is that the sound from all of your speakers arrives at the listening position at the same time - and this is the most precise way to do that.)
I would also point out that, as far as I'm concerned, people are WAY too fussy about things like frequency response... Sit in one spot, nail the microphone stand to the floor, mark all the speaker positions with masking tape, and you can get a very precise reading... And you'd better then be prepared to sit in one of those dentist chair things when you listen to the result...
But then, move something just a few inches, or have the humidity go up a bit, and it's going to be a dB or two different... This is far less of an issue with subs because very low frequencies and long wavelengths are involved... But this sort of fussy precision is still a losing battle...
Consider yourself lucky if you can manage a response that is flat within a few dB over a reasonably large listening area... And if you can get an impulse response that actually looks more or less like it's supposed to, with no major spreading, or flat out multiple peaks... (Or seriously think about headphones...) Using an impulse test click, or a carefully calibrated chirp or sweep, is a great way for software to gather a lot of useful information, all at once. But it isn't always anywhere near the best way to collect information that a human is going to use to make manual adjustments.
We humans often find a simple test that collects exactly the information we need to be far more precise and simple to use.
REW can be set to play a timing chime at the beginning of every sweep that I think you can use for this. This is one area ive tried to learn more about. Keith I agree that the o scope measurements will indeed be better but I guess we have different views on the time alignment of speakers. I’ve done the click method a long tome ago before I got into REW. And for subwoofers I’ll agree that looking for positive summation across all seating positions will yield better results better overall results then trying to mathematically time align using REW. When dealing with horns it’s a bit trickier to do it by ear since you have phase shifts around tuning and looking at the impulse is super helpful for getting multiple subs to play nice without literal hours wasted. Not something you can really deal with by ear unless you have a ton of time on your hands. With mains I’ve found that to get the best imaging for listening all listening positions is to take multiple measurements and even toe the left speaker in basically pointing at the right seat and left seat for the right speaker. This really widens the sweet spot. In reality we could prob have a super awesome conversation about the different methods of audio theory and have a few glasses of whisky while doing it! Sounds like a killer night but that’s not really the issue I was trying to bring to light. The issue is trying to bring to light is that when you send an LFE signal (hdmi4) from REW no crossover setting should be in play...period. I should be able to carry the LFE signal up to the applied internal crossover (which is it 150? Can you confirm)I also agree that while REW might not be the most reliable and perfect software it’s pretty amazing for what it is. To get the measurements I sent above the only thing that was changed was swapping the XMC temporarily for my marantz in a different room. Changing nothing else it worked as expected so I know it’s not a setting issue. I would be the first to admit if it was something I was doing but I’ve been using REW for many years and have a very good grasp on its capabilities and limitations. I follow the audio theory REW forum nearly daily and I can’t recall a single issue where LFE was applying a crossover or playing incorrectly. So same computer same minidsp only swapping the receiver and setting LFE frequency to 250 boom works perfectly as expected. Also note the the measurements were taking about 3 inches from the mouth of the horn to eliminate the room nodes and really get a good comparison of the build to the hornres response. My concern here is that if I set the crossover to all my speakers to say 60 or 80 or wherever blends the best is that the LFE that is being sent is being filtered and not being sent up to the 120hz that movies are typically mastered at. Above this post is exactly the graph I would expect that shows a very nice frequency response all the way to whatever LFE crossover is applied into the xmc1 he was using. What I’m seeing is looks to be a filter is being applied around 60-80 attenuating the signal that shouldn’t be. |
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Post by foggy1956 on May 3, 2020 18:15:26 GMT -5
Yeah would be much easier in the same room lol. LFE encoded signal sent to the XMC shouldn’t change the REW reading no matter if set to mono or LFE. Bc even in mono the sub still controls the LFE signal. Only difference is in mono it’s being asked to also handle anything below crossover points of speakers. Problem is that’s not how it works here. When set to mono an LFE only signal only plays to the crossover. So for instance let’s say any channel has a crossover of 80. If I then send an LFE only signal to the Xmc2 it applies a crossover at 80. Nothing else should be in play here at all. That’s how ASIO and REW work Can you provide a screenshot of your settings in REW? Unfortunately, my REW laptop is down, so I can't show you how mine was configured, but I'm pretty sure I sent a sweep using HDMI 4 in ASIO, as was able to get this sweep on my XMC-1 (I haven't messed with it on the XMC-2 yet): This is how you want it to look, right? Very nice sweeps |
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Post by kahodges1721 on May 3, 2020 18:17:53 GMT -5
Yeah would be much easier in the same room lol. LFE encoded signal sent to the XMC shouldn’t change the REW reading no matter if set to mono or LFE. Bc even in mono the sub still controls the LFE signal. Only difference is in mono it’s being asked to also handle anything below crossover points of speakers. Problem is that’s not how it works here. When set to mono an LFE only signal only plays to the crossover. So for instance let’s say any channel has a crossover of 80. If I then send an LFE only signal to the Xmc2 it applies a crossover at 80. Nothing else should be in play here at all. That’s how ASIO and REW work Can you provide a screenshot of your settings in REW? Unfortunately, my REW laptop is down, so I can't show you how mine was configured, but I'm pretty sure I sent a sweep using HDMI 4 in ASIO, as was able to get this sweep on my XMC-1 (I haven't messed with it on the XMC-2 yet): This is how you want it to look, right? Yup exactly that’s how it should look. That’s what I’m not getting here. Now granted I’m not taking measurements at my MLP and no REW filters are being applied to smooth it since I’m comparing the model to the build but frequency response is dead on what I’m saying should happen but doesn’t. |
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Post by bluescale on May 3, 2020 19:05:15 GMT -5
Can you provide a screenshot of your settings in REW? Unfortunately, my REW laptop is down, so I can't show you how mine was configured, but I'm pretty sure I sent a sweep using HDMI 4 in ASIO, as was able to get this sweep on my XMC-1 (I haven't messed with it on the XMC-2 yet): This is how you want it to look, right? Yup exactly that’s how it should look. That’s what I’m not getting here. Now granted I’m not taking measurements at my MLP and no REW filters are being applied to smooth it since I’m comparing the model to the build but frequency response is dead on what I’m saying should happen but doesn’t. I wish my laptop was working so I could do a quick test for you. I don't have time right now to fire up my projector, install and configure REW on my HTPC, and run the test. I'm *supposed* to be working on a paper at the moment. If you get a moment, provide the screenshot of your REW configuration before running the sweep. Hopefully we can spot something there, and it's not a bug in the bass management of the processor. |
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Post by bluescale on May 3, 2020 19:10:56 GMT -5
Can you provide a screenshot of your settings in REW? Unfortunately, my REW laptop is down, so I can't show you how mine was configured, but I'm pretty sure I sent a sweep using HDMI 4 in ASIO, as was able to get this sweep on my XMC-1 (I haven't messed with it on the XMC-2 yet): This is how you want it to look, right? Those are pretty Thanks, man. I've spent a lot of time on this room. The entire ceiling is basically a giant bass trap, which went a long way toward correcting a lot of the problems I was facing. I also have a lot of bass trapping in the front of the room. It's not the prettiest room in the world. It's very utilitarian, in fact. But since the room is *only* used as an theater room, once the lights are off, I can't see any of the panels/traps anyway. |
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Post by kahodges1721 on May 3, 2020 19:20:57 GMT -5
Yup exactly that’s how it should look. That’s what I’m not getting here. Now granted I’m not taking measurements at my MLP and no REW filters are being applied to smooth it since I’m comparing the model to the build but frequency response is dead on what I’m saying should happen but doesn’t. I wish my laptop was working so I could do a quick test for you. I don't have time right now to fire up my projector, install and configure REW on my HTPC, and run the test. I'm *supposed* to be working on a paper at the moment. If you get a moment, provide the screenshot of your REW configuration before running the sweep. Hopefully we can spot something there, and it's not a bug in the bass management of the processor. Here are the setting used for the test.   If you have a keen eye you can see that I ran sweeps on every speaker in order to apply some PEQ to them in the Xmc2. Everything works just as expected except the LFE. In order to get it to work I had to set the center to small and raise the crossover up to 200hz even when the sub is set as LFE. No matter what I did the crossover applied to the center channel was being applied to LFE signals which is not how it should work. If I set the center to large and the center sub to LFE it still maintained the crossover that was previously applied before switching to large. It’s quite odd for sure but something is a miss. |
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Post by geebo on May 3, 2020 19:31:43 GMT -5
I wish my laptop was working so I could do a quick test for you. I don't have time right now to fire up my projector, install and configure REW on my HTPC, and run the test. I'm *supposed* to be working on a paper at the moment. If you get a moment, provide the screenshot of your REW configuration before running the sweep. Hopefully we can spot something there, and it's not a bug in the bass management of the processor. Here are the setting used for the test. If you have a keen eye you can see that I ran sweeps on every speaker in order to apply some PEQ to them in the Xmc2. Everything works just as expected except the LFE. In order to get it to work I had to set the center to small and raise the crossover up to 200hz even when the sub is set as LFE. No matter what I did the crossover applied to the center channel was being applied to LFE signals which is not how it should work. If I set the center to large and the center sub to LFE it still maintained the crossover that was previously applied before switching to large. It’s quite odd for sure but something is a miss. Are you trying to apply PEQ to the sub outputs? Are you aware the PEQ is not working for the sub outputs? |
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Post by kahodges1721 on May 3, 2020 19:46:45 GMT -5
Here are the setting used for the test. If you have a keen eye you can see that I ran sweeps on every speaker in order to apply some PEQ to them in the Xmc2. Everything works just as expected except the LFE. In order to get it to work I had to set the center to small and raise the crossover up to 200hz even when the sub is set as LFE. No matter what I did the crossover applied to the center channel was being applied to LFE signals which is not how it should work. If I set the center to large and the center sub to LFE it still maintained the crossover that was previously applied before switching to large. It’s quite odd for sure but something is a miss. Are you trying to apply PEQ to the sub outputs? Are you aware the PEQ is not working for the sub outputs? No the only thing I was doing for the sub was verification of the build. I do all PEQ for subs in the mini dsp. I was planning on doing the rest of the system but got sidetracked trying to figure this issue out. Then I gave up and went and played a round of golf lol |
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Post by bluescale on May 3, 2020 20:05:44 GMT -5
I wish my laptop was working so I could do a quick test for you. I don't have time right now to fire up my projector, install and configure REW on my HTPC, and run the test. I'm *supposed* to be working on a paper at the moment. If you get a moment, provide the screenshot of your REW configuration before running the sweep. Hopefully we can spot something there, and it's not a bug in the bass management of the processor. Here are the setting used for the test. Yep, those settings are all correct, which isn't surprising since you've got a lot of experience with REW. Have you tried bypassing the miniDSP, just as a test? While it's unlikely, perhaps something's gone wonky there. If connecting the subs directly to the XMC-2 doesn't work, or if you can't do that for whatever reason, screenshots of your input and output settings on the miniDSP might be useful. I'm grasping at straws, since it all works fine with your old processor, but might as well look at the basics. I think your next step is to try a factory reset on the XMC-2 to see if that makes a difference. |
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Post by kahodges1721 on May 3, 2020 21:35:43 GMT -5
Here are the setting used for the test. Yep, those settings are all correct, which isn't surprising since you've got a lot of experience with REW. Have you tried bypassing the miniDSP, just as a test? While it's unlikely, perhaps something's gone wonky there. If connecting the subs directly to the XMC-2 doesn't work, or if you can't do that for whatever reason, screenshots of your input and output settings on the miniDSP might be useful. I'm grasping at straws, since it all works fine with your old processor, but might as well look at the basics. I think your next step is to try a factory reset on the XMC-2 to see if that makes a difference. I have not tried to bypass the mini dsp but this is the same minidsp I’ve been using for years and it would be very odd to see a lingering filter that comes and goes with the receiver. My amps for the subs do not have rca inputs and I do not have xlr cables long enough to bypass the minidsp currently but I really doubt that’s it. I’m away from my computer right now but can send some tomorrow. Basically I used an unused preset opened the PEQ to ensure no filters on any channel and then opened the filters and bypassed everything. These subs are on input 1 but output of subs are on input 1 and 2. Both show the same thing when measured individually by turning one off at a time in the minidsp. Input 1 typically defaults to a low pass at 1000 and input 2 defaults to a high pass at 1000hz so i would expect one to play correct and the other not play at all if that was forgotten...which I’ve done before for sure! Lol. Since it was affecting both I thought it may be something applied on the input but nope nothing there. I say all of this but there is a very important statement I made and that is the LFE channel follows the center channel crossover. So basically you can get it to work by moving the crossover to 200hz BUT the graph shouldn’t change based on any crossover since it’s the LFE signal. There isn’t a setting to change the LFE low pass from what I can see in the Xmc2 so sending the LFE should be the same every time. Now I know the next question is are you sure the LFE isn’t getting messed up and it’s sending the center channel instead...well I tested that also thinking the same. For example let’s move the crossover down to 60hz and send a sweep on LFE (hdmi4) from 0-1000 I would expect that if it was sending the center instead that after 60hz or at some point the center would pick up and start playing. It doesn’t only the sub plays as it should. Has anyone else ran REW sweeps using the Xmc2? I’m shocked there doesn’t seem to be as many as I expected. |
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ttocs
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Post by ttocs on May 3, 2020 23:36:32 GMT -5
Has anyone else ran REW sweeps using the Xmc2? I’m shocked there doesn’t seem to be as many as I expected. I just bought a miniDSP 2x4HD but haven't used it yet, so I don't have any experience with it. I've been following your journey in hopes of learning about what to expect. I can try something simple to begin with to see if I can help, but I would need to know what to do. I have a MacBook Pro so if a Windows computer is needed then that's gonna be a little tough. I've got some old ones running XP I can maybe use, but it's a bit sketchy. |
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Post by foggy1956 on May 4, 2020 6:04:45 GMT -5
Yep, those settings are all correct, which isn't surprising since you've got a lot of experience with REW. Have you tried bypassing the miniDSP, just as a test? While it's unlikely, perhaps something's gone wonky there. If connecting the subs directly to the XMC-2 doesn't work, or if you can't do that for whatever reason, screenshots of your input and output settings on the miniDSP might be useful. I'm grasping at straws, since it all works fine with your old processor, but might as well look at the basics. I think your next step is to try a factory reset on the XMC-2 to see if that makes a difference. I have not tried to bypass the mini dsp but this is the same minidsp I’ve been using for years and it would be very odd to see a lingering filter that comes and goes with the receiver. My amps for the subs do not have rca inputs and I do not have xlr cables long enough to bypass the minidsp currently but I really doubt that’s it. I’m away from my computer right now but can send some tomorrow. Basically I used an unused preset opened the PEQ to ensure no filters on any channel and then opened the filters and bypassed everything. These subs are on input 1 but output of subs are on input 1 and 2. Both show the same thing when measured individually by turning one off at a time in the minidsp. Input 1 typically defaults to a low pass at 1000 and input 2 defaults to a high pass at 1000hz so i would expect one to play correct and the other not play at all if that was forgotten...which I’ve done before for sure! Lol. Since it was affecting both I thought it may be something applied on the input but nope nothing there. I say all of this but there is a very important statement I made and that is the LFE channel follows the center channel crossover. So basically you can get it to work by moving the crossover to 200hz BUT the graph shouldn’t change based on any crossover since it’s the LFE signal. There isn’t a setting to change the LFE low pass from what I can see in the Xmc2 so sending the LFE should be the same every time. Now I know the next question is are you sure the LFE isn’t getting messed up and it’s sending the center channel instead...well I tested that also thinking the same. For example let’s move the crossover down to 60hz and send a sweep on LFE (hdmi4) from 0-1000 I would expect that if it was sending the center instead that after 60hz or at some point the center would pick up and start playing. It doesn’t only the sub plays as it should. Has anyone else ran REW sweeps using the Xmc2? I’m shocked there doesn’t seem to be as many as I expected. I'm hoping my xmc-2 shows this week, I run 2 subs through a 2x4 advanced, I will run a sweep as soon as I get things set up. What happens if you run a sweep on your left front speaker while that output from the xmc is plugged into your subs? |
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