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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42563

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But Dirac can't (or can it?) adjust the time difference between each element of a 3-way channel. That is, unless you use more Dirac channels.

I'm just thinking maybe that is the reason why 7 channel sounded better and with correct delay adjustments 5 ch would be as good. Who knows.. I'm definately going to try with 7 Dirac channels.


I believe the delay on the Dirac Live tab is just showing the overall delay for that channel - but I also believe it can adjust delay/phase independent of frequency within that channel. This is why I think it can work on driver groups per Dirac channel...

But, I don't think it can adjust delay/phase independently for different drivers at the same frequency (crossover regions) on the same channel - which is why I think assigning each driver it's own Dirac channel is beneficial if the drivers are at different path lengths from the listening position... Improved coherence in the crossover regions.

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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42564

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But Dirac can't (or can it?) adjust the time difference between each element of a 3-way channel. That is, unless you use more Dirac channels.

I'm just thinking maybe that is the reason why 7 channel sounded better and with correct delay adjustments 5 ch would be as good. Who knows.. I'm definately going to try with 7 Dirac channels.


I believe the delay on the Dirac Live tab is just showing the overall delay for that channel - but I also believe it can adjust delay/phase independent of frequency within that channel. This is why I think it can work on driver groups per Dirac channel...

But, I don't think it can adjust delay/phase independently for different drivers at the same frequency (crossover regions) on the same channel - which is why I think assigning each driver it's own Dirac channel is beneficial if the drivers are at different path lengths from the listening position... Improved coherence in the crossover regions.


This is a question of mine too. I'd love to hear @devteam chime in on Dirac's capabilities in this area.

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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42569

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Dear All

Great news! We've now finally figured out how to squash that annoying "low level" error bug.. :-) It was a miscommunication between the software and our DSP core. Please go to the user downloads section and grab the latest plugin (v1.6). You only need to
a) Install the new plugin / It will automatically reload your xml config as it's just an upgrade.
b) Synch to the unit so you're live
c) Click "Restore" -> "Upgrade DSP Program"
It will solve this annoying little warning :-)

Also note that we upgraded the "MCU firmware" for a bug on the subwoofer volume control. To fix this issue, make sure to upgrade the firmware as per the user manual (i.e. using the SD card to upgrade the unit).

Have fun and a big shout out to all the great feedback we've been receiving from @TimoJ, Naiku and denver8me4dinner. Make sure to increase their Karma for their feedback. :-)

DevTeam
miniDSP, building a DSP community one board at a time.
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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42570

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But Dirac can't (or can it?) adjust the time difference between each element of a 3-way channel. That is, unless you use more Dirac channels.

I'm just thinking maybe that is the reason why 7 channel sounded better and with correct delay adjustments 5 ch would be as good. Who knows.. I'm definately going to try with 7 Dirac channels.


I believe the delay on the Dirac Live tab is just showing the overall delay for that channel - but I also believe it can adjust delay/phase independent of frequency within that channel. This is why I think it can work on driver groups per Dirac channel...

But, I don't think it can adjust delay/phase independently for different drivers at the same frequency (crossover regions) on the same channel - which is why I think assigning each driver it's own Dirac channel is beneficial if the drivers are at different path lengths from the listening position... Improved coherence in the crossover regions.


This is a question of mine too. I'd love to hear @devteam chime in on Dirac's capabilities in this area.



Okay


But Dirac can't (or can it?) adjust the time difference between each element of a 3-way channel. That is, unless you use more Dirac channels.

I'm just thinking maybe that is the reason why 7 channel sounded better and with correct delay adjustments 5 ch would be as good. Who knows.. I'm definately going to try with 7 Dirac channels.


I believe the delay on the Dirac Live tab is just showing the overall delay for that channel - but I also believe it can adjust delay/phase independent of frequency within that channel. This is why I think it can work on driver groups per Dirac channel...

But, I don't think it can adjust delay/phase independently for different drivers at the same frequency (crossover regions) on the same channel - which is why I think assigning each driver it's own Dirac channel is beneficial if the drivers are at different path lengths from the listening position... Improved coherence in the crossover regions.




So having separate channels for each driver is ideal, as Dirac will be able to set a delay that’s targeted at the acoustical center of that driver.

If a speaker pair is used on a single channel Dirac will decide how to delay that based on the transfer function of what it sees as a sum of the two drivers, it doesn't know how many speakers are on any given channel. It looks at the response of that channel either as a individual or a sum of more than 1, it will look for what it needs to do to get the transfer functions to work best between the two channels. It’s going to try to make them match each other.

Some parts it will ignore and some parts it will correct. If two speakers are on a single channel it may or may not use convolution to get a better alignment on the speakers.

It can create a all pass for the entire channel where it may move the phase in a way the aligns the drivers, it may decide there alignment is good enough to use as there distance apart isn’t severe enough to have to. But again it doesn’t know how many speakers are on any channel.

But does it align them.....well to a degree yes. But that’s not what it’s looking for. It’s trying to make the impulse invertible and trying to make the response (time domain and frequency domain) match each other on both stereo channels.

It has a finite amount of processing power to do some of its corrections. So I believe it makes the best use of its abilities within the given processing power at hand and makes the best use of it.
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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42577

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So having separate channels for each driver is ideal, as Dirac will be able to set a delay that’s targeted at the acoustical center of that driver.

What about if you first use separate Dirac channels, check how it sets the element delays and then use those to set the output channel delays for single channel system (with suitable calculations so that only the time difference between one channel elements is used) ? I think I'll try also that, someday...

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Last edit: by TimoJ.

New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42578

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The point I was trying to make is that I believe the delays displayed on the Dirac Live tab are not the only delay/phase adjustments it is performing. I think that delay displayed is just the overall delay applied to that channel but I believe it can adjust delay/phase for specific frequency groups also within that channel as needed to achieve it's goal. Like for instance it can correct for the phase rotation the xover filters on the outputs induce. I would think these adjustments need to be different for the LP/HP drivers which is why I think assigning a discrete Dirac channel to each driver is beneficial.
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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42579

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Great news! We've now finally figured out how to squash that annoying "low level" error bug.. :-) It was a miscommunication between the software and our DSP core. Please go to the user downloads section and grab the latest plugin (v1.6).


Excellent news, will download that shortly.

I would think these adjustments need to be different for the LP/HP drivers which is why I think assigning a discrete Dirac channel to each driver is beneficial.


This is why I wish I had just 1 more Dirac channel!! I think at some point I am going to try a tune with a Dirac channel per driver but not using rear fill, likely ending up with 3 presets stored - a 5 channel, a 7 channel with rear fill and a 7 channel without rear fill.

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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42580

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This is why I wish I had just 1 more Dirac channel!! I think at some point I am going to try a tune with a Dirac channel per driver but not using rear fill, likely ending up with 3 presets stored - a 5 channel, a 7 channel with rear fill and a 7 channel without rear fill.


Also try rear fill with just one Dirac channel. Adjust channel delays and try what Dirac does with both rear speakers playing. It might be good enough for fill...
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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42581

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Also try rear fill with just one Dirac channel. Adjust channel delays and try what Dirac does with both rear speakers playing. It might be good enough for fill...


Thanks, that is actually a great suggestion. In my case the only difference in my rear fill is the L/R levels, crossovers & TA match between them both, so it's almost a waste to give each their own channel, but then to combine the mids / midbass together.

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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42582

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The point I was trying to make is that I believe the delays displayed on the Dirac Live tab are not the only delay/phase adjustments it is performing. I think that delay displayed is just the overall delay applied to that channel but I believe it can adjust delay/phase for specific frequency groups also within that channel as needed to achieve it's goal. Like for instance it can correct for the phase rotation the xover filters on the outputs induce. I would think these adjustments need to be different for the LP/HP drivers which is why I think assigning a discrete Dirac channel to each driver is beneficial.



Correct , ;)

However I don’t think it’s goal is to “flatten phase” Perseus. But yes it can remove crossover phase and other phase issues, more room related issues. The end result is uniform phase on both left and right channels. You can’t hear a phase issue unless there’s another speaker playing the same thing that has different phase. So it will make whatever changes it can calculate based on what it measured to make both sides match each other. So yes some of the phase on crossovers would be adjusted , but it might ajust the rest of the response around the inband if it calculates it to do it that way with less processing power. Either way is same thing....it depends how the speakers are “phased” when measured and a whole bunch of other variables :dry:


Imagine a single filter that does everything instead of a series of peqs or phase eqs :huh: ,

I’ve measured the response of Dirac using REw in a loopback many times it took awhile to make sense of what its doing. I wanted (expected) flat phase (0 or -360) all the way through the magnitude and it wasn’t so , there was still wraps and downhill (even with time of flight removed)

But the left and the right side were almost exactly the same .....that’s what makes it sound so good. And there wasn’t any radical flips it was smooth , just not “flat” .

Hope that makes sense

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Last edit: by denver8me4dinner.

New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42584

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Bug fix on version 1.6 works perfectly, no more annoying low level message. :)

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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42595

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And plugin's subwoofer level display still doesn't work correctly. Now it seems to jump to 8dB after adjusting...

It actually works, you have to do a firmware upgrade with the sdcard, not a DSP upgrade via the plugin.
But the way it works is a little confusing. It effects to the output level (of selected channel/s) exactly at the same place as the output sliders. But adjusting via the subwoofer setting is "hidden" i.e. not shown in the output level settings. So you could have there channel output set to +12dB and still have adjusted the same channel to -20dB via the subwoofer function.


I think it's still buggy. Or maybe I just don't get the logic behind it...
I set it to 0dB and adjusted the output of my sub channel to -5dB (via the output slider tab). At this time the sub display was still showing 0dB. I then did a Dirac calibration and started the plugin again. And now the sub display showed -5dB. I think it should still show 0dB since it's supposed to show a "hidden" setting, not the output slider setting.

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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42596

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Finally did another Dirac calibration, with 5 Dirac channels. This time I was sitting inside the car. Much better than last time. Now also Dirac delays make more sense than last time i.e. sub is at 0ms when last time it had 5ms delay... Imaging is good, center is stable and the best part is that bass (mostly from the sub) comes from the center of the dash and stays there even if you move around in your seat. I did use 48dB LR filtering for the sub. Also found a smaller laptop that fits and sits perfectly to the space between the gear lever and the armrest. Operating the computer is much better now.

I did notice that the system now has a little more hissing noise, even when the CDSP's output volume is turned down. Only pressing mute cuts it. Not sure how Dirac could effect to this since it's before the output level adjustments. Need to do more testing and tweak amp input gains a little lower.
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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42597

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best part is that bass (mostly from the sub) comes from the center of the dash and stays there even if you move around in your seat.


It was a memorable revelation when I was able to get this in my car :)

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New automotive Dirac Live: CDSP 8x12 DL 3 years 5 months ago #42598

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It was a memorable revelation when I was able to get this in my car :)


I have owned many DSP's, before this I had (still have) PXA-H800, but was never able to get bass to stay in the dash if you moved around, there was always "something" coming from the back if you turned your head. Then again, the system maybe was not fully optimized but now with few minutes of Dirac you get better results than with hours of tuning :)
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