Welcome, Guest
Username: Password: Remember me

NOTE: This is a "Community" forum. Please be mindful that community members are here to help as part of a community effort. We therefore appreciate your effort in keeping this forum a happy place!

If you have a specific issue (e.g. hardware, failure) and want help from our support team, please use our tech support portal (Support menu - > Contact Us).
Thanks a lot of your help in making a better community.

TOPIC:

Dirac advances settings 10 months 2 weeks ago #51508

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269

Hi, when you say "divide" do you mean just subtract one from the other?

Without dirac shouldn't the reading you get just be a flat 0db?


No, I mean divide. 'A/B' in REW trace arithmetic. Measurement A with Dirac on and measurement B with Dirac off.

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51509

  • asx77
  • asx77's Avatar Topic Author
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 326
  • Thank you received: 39
I've just had a look at REW and see the menu/control panel you mean. Yes agree this is more accurate than looking by eye at the output meters. Quicker too!

The only confusion I still have is the "divide" rather than "subtract"

If with dirac offI get a -12db
And with dirac on I get -8db
The boost is 4db subtract g one from the other. Dividing gives me a % value. Or is it just REW terminology?

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51510

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269
Filters applied in the frequency domain are multiplicative (as opposed to a convolution in the time domain). So:

Dirac_on_spectrum = Dirac_off_spectrum X Filter.

Hence if you want to calculate the filter you want to divide. Note this approach also shows the phase changes by
Dirac if you're interested.
The following user(s) said Thank You: asx77

Please Log in or Create an account to join the conversation.

Last edit: by Ultrasonic.

Dirac advances settings 10 months 2 weeks ago #51511

  • asx77
  • asx77's Avatar Topic Author
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 326
  • Thank you received: 39
Lol I can't help but be interested. Right that's my job for later!

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51512

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269
Thinking about this, the reason what you see looks like an addition rather than a multiplication is because you're looking at a dB scale.

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51513

  • asx77
  • asx77's Avatar Topic Author
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 326
  • Thank you received: 39
Actually one other question. So the mic has to remain in the same position when the measurements are taken but will the filters appear the same regardless of where the mic is placed? So if it close to but not exactly in my favourite listening spot does it matter?
Thanks

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51514

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269

will the filters appear the same regardless of where the mic is placed?


Essentially, yes. What will vary with position is the signal-to-noise as a function of frequency which will change the result slightly, most significantly close to minima of the spectrum.

The comparisons you made previously will have been affected in exactly the same way.

Try a couple of locations and compare if you're really curious. I'll be honest I never have. Bear in mind that none of this is to try to get the most accurate result possible but I think it's easily good enough for the purposes here.

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51515

  • asx77
  • asx77's Avatar Topic Author
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 326
  • Thank you received: 39
Yes I think your approach makes perfect sense now I understand a bit better.

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51518

  • 9radua1
  • 9radua1's Avatar
  • Offline
  • New Member
  • New Member
  • Posts: 15
  • Thank you received: 4

How does Dirac secure headroom if not by volume calibration?


It doesn't, hence the advice in this thread. I'm not saying this is smart but it's the truth.

As you don't seem to be believing me, here are some other threads on this topic, starting with one with advice along similar lines from miniDSP's devteam:

www.minidsp.com/forum/dirac-series-suppo...-preventing-clipping

www.minidsp.com/forum/shd-series/16778-s...stortion-2-ch-purity

www.minidsp.com/forum/dirac-series-suppo...nd-internal-headroom


Ok, I read through those threads. Dev team’s answers are a bit convoluted. Maybe a language barrier. In any case, it seems that the different products don’t employ the same gain structure.

With the 22D, dev says “Dirac will makeup the level afterwards”. What does that mean if not some sort of compensating gain setting internal to Dirac?

Are you working with the SHD? In my SHD it is clearly audible, that before I run the Dirac Live Calibration Tool, the gain level is higher. After I make the filters and load them into the SHD, the gain is lower by about 10 dB or so. Also, when I rerun the calibration tool, the gain level shifts. That’s why it seems to me that it depends on the measurements and/or the volume settings inside the Dirac Tool.

I suspect that if someone would max out the volume settings in Dirac and make all measurements just below clipping level, then there would be an increased risk of clipping the output as well.

I have used the SHD in many rooms on many speakers and amps. I have never experienced clipping. Before that, I used the VST plug-in version of v1 or v2. There, I did experience clipping, but that could be stopped by attenuating the plug-in volume slider. I just can’t imagine Dirac hasn’t some sort of automated setting in the calibration tool for securing something like 10 dB headroom or more.

Anyway, I will write to Flak about this and get an answer.

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51519

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269
I believe my comments apply to Dirac v2 and v3 on all miniDSP platforms. I only have personal experience of running Dirac on an SHD but the recent posts in the threads I linked to definitely apply to at lease the DDRC24 as well.

Please Log in or Create an account to join the conversation.

Last edit: by Ultrasonic.

Dirac advances settings 10 months 2 weeks ago #51520

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269

I just can’t imagine Dirac hasn’t some sort of automated setting in the calibration tool for securing something like 10 dB headroom or more.


I don't know how you can even question it based on what I linked to.

In terms of whether you've experienced it - do you run your miniDSP at 0 dB master volume, and with no attenuation applied within the plugin on either inputs or outputs? Note it will also only become apparent on recordings with signals close to the digital peak level.

Anyway, I will write to Flak about this and get an answer.


Who?

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51529

  • 9radua1
  • 9radua1's Avatar
  • Offline
  • New Member
  • New Member
  • Posts: 15
  • Thank you received: 4


I don't know how you can even question it based on what I linked to.

In terms of whether you've experienced it - do you run your miniDSP at 0 dB master volume, and with no attenuation applied within the plugin on either inputs or outputs? Note it will also only become apparent on recordings with signals close to the digital peak level.

Anyway, I will write to Flak about this and get an answer.


Who?


Sorry, I meant Flavio. The guy from Dirac support that’s on all the forums (maybe not this one?)

He answered:

Flavio Fellah commented:

Hello,
yes, in the hardware products the manufacturer assigns appropriate headroom.

I expect that it's something like 10 dBs but miniDSP can answer precisely


That fits with my experience that there’s around 10dB of headroom automatically inserted somewhere in the floating math before the Dirac filters. If this is not correct, would be nice to have @devteam comment here.

You asked if I’m running the SHD at full volume when experiencing this. Yes and no. It doesn’t matter what the SHD master volume is at, the attenuation is the same. That also fits with what Dev team said in the thread you linked to, that the master volume is separate from the gain structure around the filters.

PS. I’m running 1.19 firmware, 1.13d2 plug-in.

Please Log in or Create an account to join the conversation.

Last edit: by 9radua1.

Dirac advances settings 10 months 2 weeks ago #51530

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269

Sorry, I meant Flavio. The guy from Dirac support that’s on all the forums (maybe not this one?)


Sadly no, nobody from Dirac support posts here. At least not while declaring this status.

He answered:

Flavio Fellah commented:

Hello,
yes, in the hardware products the manufacturer assigns appropriate headroom.

I expect that it's something like 10 dBs but miniDSP can answer precisely


I'm afraid that whilst Flavio may hope and expect that miniDSP hardware provides headroom, it does not. Note that Flavio clearly didn't know what miniDSP hardware does. I feel the information in the links I provided shows this, most specifically the example of at least one person who have experienced distortion 'fixed' by providing the required headroom. I have seen others.

You asked if I’m running the SHD at full volume when experiencing this. Yes and no. It doesn’t matter what the SHD master volume is at, the attenuation is the same.



What I asked was whether you run your miniDSP at 0 dB master volume, and with no attenuation applied within the plugin on either inputs or outputs. This matters as you're not going to have an issue if you are routinely applying sufficient attenuation anyway.

I care about this as I don't want other users to be mislead. I'm totally with you that what you think happens would be logical but sadly it is not reality.

Please Log in or Create an account to join the conversation.

Last edit: by Ultrasonic.

Dirac advances settings 10 months 2 weeks ago #51533

  • 9radua1
  • 9radua1's Avatar
  • Offline
  • New Member
  • New Member
  • Posts: 15
  • Thank you received: 4

I feel the information in the links I provided shows this, most specifically the example of at least one person who have experienced distortion 'fixed' by providing the required headroom.


Just for clarity, that was not the SHD, but the older DDRC-24.

My experience is with the SHD. I thought it was the same for all Dirac units, but as I said after reading the threads, I see that @devteam indicated different gain structures in the units.

So it may very well be that the DDRC can clip somehow, while the SHD doesn’t. And even if there’s a 10dB or more headroom in the SHD, it could theoretically still clip if the filters surpassed that on rare occasion.

Maybe we should hop over to ASR and have one of those guys measure and test for headroom. Or find Amir’s original thread and ask, if he noticed any headroom when he measured the SHD a while back. Otherwise we’re just pedaling anecdotal evidence.

Please Log in or Create an account to join the conversation.

Dirac advances settings 10 months 2 weeks ago #51534

  • Ultrasonic
  • Ultrasonic's Avatar
  • Away
  • Platinum Member
  • Platinum Member
  • Posts: 1454
  • Thank you received: 269

Just for clarity, that was not the SHD, but the older DDRC-24.


Actually no. I've just just had a quick look at the threads I linked you to and @jmcomp124 was reporting distortion issues with his SHD Studio (which I'd expect to behave identically to the SHD). @Tonn_J has also reported a similar issue with his DDRC-24 though.

I thought it was the same for all Dirac units, but as I said after reading the threads, I see that @devteam indicated different gain structures in the units.


All of the posts I have seen from @devteam relating to this issue require the user to provide the necessary headroom somewhere within software settings. I have not seen a single post to indicate automatic attenuation that is not visible to the user. Please post a link if you've seen otherwise.

Maybe we should hop over to ASR and have one of those guys measure and test for headroom. Or find Amir’s original thread and ask, if he noticed any headroom when he measured the SHD a while back. Otherwise we’re just pedaling anecdotal evidence.


Please do and report back. I occasionally browse ASR but don't regularly post there. If someone had a way to directly look at the digital or analogue outputs this could be tested for safely. I could easily generate a condition where I'd expect digital clipping to occur but I'm not going to risk damaging my speakers by trying it.

You never answered my question about your own experience though. Do you routinely run your SHD at 0 dB master volume and with no input or output attenuation within the plugin?

Please Log in or Create an account to join the conversation.

Moderators: devteam