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## nanoAVR DL bass management issue 7 years 11 months ago #17806

 john.reekie Offline Platinum Member Posts: 3778 Thank you received: 1593 Hi there, that isn't how it works. With your bass management turned on in the AVR, the nanoAVR DL will "see" and therefore equalize the combined response. As far as the nanoAVR DL is concerned, the crossover, sub, and speaker are all "one speaker." Hope that helps Please Log in or Create an account to join the conversation.

## nanoAVR DL bass management issue 7 years 11 months ago #17809

 sheraz Topic Author Offline Junior Member Posts: 26 Thank you received: 0 Hi there, that isn't how it works. With your bass management turned on in the AVR, the nanoAVR DL will "see" and therefore equalize the combined response. As far as the nanoAVR DL is concerned, the crossover, sub, and speaker are all "one speaker." Hope that helps Thanks for your response. So that I understand clearly your response, let's have a scenario to understand it better. Current System: 5.1 Cross-Over set in ave: 80. Assumptions: Left Speaker has a peak of 10db at 50hz Right speaker has a peak of 5db at 50hz Center has a dip of 4db at 40 Let's not worry about sorround Process: 1 - Set cross over in avr before running Dirac to 80. 2 - Make sure all speakers are set to small in avr. 3 - Run Dirac calibration. During calculation, Dirac will sum all the speakers below 80 (cross-over) as per what you explained. In this case, the end result before filter will be A peak of 15db at 50hz (Left+Righ) A dip of 4db at 40hz (Center). Dirac will create 2 filters. First one to get rid of 15db peak and 2nd to get rid of 4db dip. End result: a flat response below 80hz for subs. Is that correct? thx. Please Log in or Create an account to join the conversation.

## nanoAVR DL bass management issue 7 years 11 months ago #17810

 john.reekie Offline Platinum Member Posts: 3778 Thank you received: 1593 No, that's not correct I did not mean that Dirac will sum all speakers. By "combined" response I meant the combined response of one speaker and the subwoofer (and the bass management filters). It does not matter if your left speaker has a 10 dB peak at 50 Hz before you turn on bass management. What matters (to Dirac) is what the response is with bass management turned on. Dirac will "see" that response on each channel, with bass management on and therefore including the filters and subwoofer, and correct for it. Hope that is clearer - ? Please Log in or Create an account to join the conversation. Last edit: by john.reekie.

## nanoAVR DL bass management issue 7 years 11 months ago #17813

 john.reekie Offline Platinum Member Posts: 3778 Thank you received: 1593 My understanding is that below cross-over, only sub produces the sound. That is, No other speaker will produce any sound but Sub. Is that correct? Mostly correct The sub and the speakers have, in effect, a crossover. So there is not a sudden transition where below 80 Hz sub plays everything and above 80 Hz the speaker plays everything. Instead, there is a transition between them, a region around 80 Hz where both the sub and the speaker are playing. Back to the scenario case with some modifications (if you don't mind ) Current System: 5.1 Cross-Over set in ave: 80. Assumptions: Left Speaker has a peak of 10db at 50hz Right speaker has a peak of 5db at 50hz Sub has no issues at 50hz. Center has a dip of 4db at 40 Sub as a peak of 3db at 40. OK, but when you say the Left Speaker has a peak of 10db at 50hz, that is without the bass management, right? When you turn on bass management, the high pass filter on the left speaker will reduce output from the speaker below 80 Hz (technically the reduction starts a bit above 80 Hz). So with bass management turned on, the left speaker will not have a 10 dB peak any more. There may be some effect still, but not 10 dB and it will be amongst all the peaks and dips in the sub response... During calculation: 1- Dirac will Run test for Left+Sub below 80. Sub has no issue at 50Hz but Left does(10db peak). In this case Dirac will apply a 10db filter for Left + Sub. No. With the bass management turned on, Dirac will not apply a 10 dB correction at 50 Hz, because it will not "see" a 10 dB peak there. At that frequency, mostly it will be the sub playing. Dirac will correct for the combined response of sub and speaker, with bass management filters turned on. It cannot see a 10 dB peak from the left speaker, because the bass management makes it not there any more. Before calibration Sub: 40 Hz: A dip of 3 db 50 Hz: Nothing wrong After calibration Sub: 40 Hz: A peak of 1 db (filter of 4db was applied for sub+center) 50 Hz: A peak of 15db (2 filters were applied. 1 for L+S and another for R+S) After calculation, We have 2 filters. 2 At 50Hz (one for left and one for right) and one at 40Hz(center+sub). No. As above, the 10 dB peak is not there anymore because of bass management. Also, Dirac does not add the correction for two channels. It just does each one separately. End Result: @40Hz Dirac improved sub response by reducing 3db dip with 1db gain. @50Hz Dirac messed up sub response. It had no issue but since Dirac measured it with speaker, it introduced filters due to speakers response. Nope Please Log in or Create an account to join the conversation. Last edit: by john.reekie.

## nanoAVR DL bass management issue 7 years 11 months ago #17815

 sheraz Topic Author Offline Junior Member Posts: 26 Thank you received: 0 Your post did make me feel better but here are the concerns that were raised. Having BM after: at this point optimization already fails because the test signal goes through bass management and Dirac measures the wrong thing. For example it will measure L plus sub when Dirac should measure just L RC applies a filter to each channel. In bass management these preprocessed channels are mixed together and are output from a speaker (here, the subwoofer) the individual RC filters aren't applicable to. If the test signal for room correction goes through bass management then everything is already completely messed up. The test signal will be played by more than one speaker (L and sub for example) when only one speaker should be measured at a time. Lets assume the room correction filters have been created correctly but they are applied before bass management. This is another source of error. The channel signals get equalized and altered by the room correction filters according to the speaker they are assigned to but now they get mixed together in bass management and are routed to the sub. In other words, the equalized signal for let's say the left speaker is reproduced by a speaker for which the equalization isn't valid, namely the sub. The result is a distorted signal. Please Log in or Create an account to join the conversation. Last edit: by sheraz.

## nanoAVR DL bass management issue 7 years 11 months ago #17816

 Jim the Oldbie Offline Elite Member Posts: 268 Thank you received: 80 I'm not a Dirac owner (yet), but the way I understand it, you have to tell the software about your speaker configuration in the initial setup phase. If you're using a separate, single subwoofer for example, Dirac will then be aware of this and base its measurements and corrections accordingly. I think I understand your concerns here. May I make a humble suggestion? At this point the Dirac product has been scrutinized pretty closely by lots of users & reviewers. If the mis-measurement scenarios you describe were occurring, they would indeed represent a significant shortcoming, and so would have been pretty thoroughly picked apart and criticized by now. Since this is not happening, perhaps it's safe to assume that the system is not making these particular mistakes, and it's OK not to worry about it? -- Jim Please Log in or Create an account to join the conversation. Last edit: by Jim the Oldbie. Reason: The crux of the biscuit is the apostrophe.

## nanoAVR DL bass management issue 7 years 11 months ago #17817

 sheraz Topic Author Offline Junior Member Posts: 26 Thank you received: 0 I'm not a Dirac owner (yet), but the way I understand it, you have to tell the software about your speaker configuration in the initial setup phase. If you're using a separate, single subwoofer for example, Dirac will then be aware of this and base its measurements and corrections accordingly. I think I understand your concerns here. May I make a humble suggestion? At this point the Dirac product has been scrutinized pretty closely by lots of users & reviewers. If the mis-measurement scenarios you describe were occurring, they would indeed represent a significant shortcoming, and so would have been pretty thoroughly picked apart and criticized by now. Since this is not happening, perhaps it's safe to assume that the system is not making these particular mistakes, and it's OK not to worry about it? -- Jim Jim, Concern is not about Dirac at all. It's more to do with wereh nanoAVR DL goes in the chain. The flow is Player --> nanoAVR DL --> AVR. Again concern has nothing to do with Dirac but how nanoAVR DL being before bass management handles the concerns. Please Log in or Create an account to join the conversation.

## nanoAVR DL bass management issue 7 years 11 months ago #17818

 john.reekie Offline Platinum Member Posts: 3778 Thank you received: 1593 Hi sheras, we had a thread all about that a while ago, perhaps you could search for it? miniDSP rep is "devteam." I did not realize that was the thrust of your question. If you really want to put bass management "before" Dirac, you can use a DDRC-88A, or a nanoAVR HD between the Player and nanoAVR DL (i.e two nanoAVR units). I'm not sure anyone has tried the latter, but I can't think of any reason it wouldn't work... Cheers Please Log in or Create an account to join the conversation.

## nanoAVR DL bass management issue 7 years 11 months ago #17822

• markus
• Offline
• Senior Member
• Posts: 68
sheraz,

Try to understand what bass management is and how it works and it should become very obvious why the only correct location for EQ is AFTER bass management:

## nanoAVR DL bass management issue 7 years 11 months ago #17844

 Jim the Oldbie Offline Elite Member Posts: 268 Thank you received: 80 Concern is not about Dirac at all. It's more to do with wereh nanoAVR DL goes in the chain. The flow is Player --> nanoAVR DL --> AVR. Again concern has nothing to do with Dirac but how nanoAVR DL being before bass management handles the concerns. Not to put too fine a point on it, but in this case, for all intents and purposes, nanoAVR DL _is_ Dirac. So the question really is how _Dirac_ handles the bass management concerns. Again, I'm not an owner, but from what I've read about nanoAVR DL, it looks like its Dirac implementation (if set up correctly) has enough awareness of its position in the signal path to get things done properly. -- Jim Please Log in or Create an account to join the conversation.

## nanoAVR DL bass management issue 7 years 11 months ago #17846

 Jim the Oldbie Offline Elite Member Posts: 268 Thank you received: 80 sheraz, Try to understand what bass management is and how it works and it should become very obvious why the only correct location for EQ is AFTER bass management I think that is exactly the point sheraz is trying to make. :o) But is this always true? There is a fair amount of magnitude & phase correction that can be done upstream from bass management. RePhase has among other features a 'global' curve that would be an example of this, if I understand it correctly. Also, nanoAVR DL's Dirac is made aware of the speaker config during setup. If it's smart enough, it should still be able to blend things properly even though it can't address & test each speaker separately? How is this different from its inability to test mids separately from tweets, for example? -- Jim Please Log in or Create an account to join the conversation.

## nanoAVR DL bass management issue 7 years 11 months ago #17847

 markus Offline Senior Member Posts: 68 Thank you received: 21 Concern is not about Dirac at all. It's more to do with wereh nanoAVR DL goes in the chain. The flow is Player --> nanoAVR DL --> AVR. Again concern has nothing to do with Dirac but how nanoAVR DL being before bass management handles the concerns. Not to put too fine a point on it, but in this case, for all intents and purposes, nanoAVR DL _is_ Dirac. So the question really is how _Dirac_ handles the bass management concerns. Again, I'm not an owner, but from what I've read about nanoAVR DL, it looks like its Dirac implementation (if set up correctly) has enough awareness of its position in the signal path to get things done properly. -- Jim Dirac Live has no knowledge where in the signal chain it operates. It sends a test signal downstream and measures the acoustical response. Then it creates a correction filter based on that response. It does that for each of its output channels. Please Log in or Create an account to join the conversation. Last edit: by markus.
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