marktjp

RME ADI-2 DAC vs Chord Qutest

Recommended Posts

38 minutes ago, Metatron said:

What's the point? since if they did not agree, one of the systems would be faulty and you'd have no way to know which one.

Dirac shows a somewhat idealised prediction of the effect of its filters. The software doesn’t, as such, have the facility to measure the post filtered response (unless one runs a new project in which case you won’t have the pre and post plots superimposed). In practice the normal technique is to take a series of readings and average them with the software placing emphasis on the first which is taken at the listening position. Without knowing the algorithm that Dirac uses it would be difficult to replicate it in REW. As the Dirac curves are a prediction they will inevitably be different to REW measurements taken with Dirac filters employed and thus it doesn’t matter if they are different.

I personally run Dirac and then make filters based on my choice of house curve, sloped to varying degrees, towards the speakers actual response, including room, at the listening position. This means that the filters aren’t trying to work against the natural “sound” of the room or speakers. In some ways Dirac is semi automated and accepting the default results will usually give a valuable improvement, if not, thankfully, quite as idealised as the software might lead one to believe. By varying the extra mic positions and adapting the house curve one can have quite a bit of control over the final result.

REW is a tool which with experience can be very useful, particularly in making comparisons, say, after moving speakers or using Dirac filters. By moving the mic a small amount, however, very different looking plots can be produced! Hence the interpretation does require experience which for us amateurs can be usefully extended by correlating curves with what they sound like. I find the ETC curve one of the most useful for seeing the reflections from the room, their timing and how far below peak they are. The frequency response plots are handy for a quick snapshot but really need to be viewed with waterfall plots at low frequencies to see where lengthy decays are occurring. The Meridian room correction system seemed to place more emphasis in reducing lengthy decays then keeping a flat frequency response. This can speed up the process of finding the best speaker position and finding the best balance between direct and reflected sound. As I use omnis and like the spacious, airy effect I can find a placement that gives a good balance between pin point imaging which on its own can sound, in practice to my ears, somewhat artificial and a spacious sound where details can be smeared. As ever it is a case of getting things in balance to get the best of both worlds. 

My experience FWIW is that taking measurements speeds up setting up a system (particularly subs) but isn’t the be all and end all. In the end I want the closest illusion of the original sound, not an analysis of the recording, and that takes careful listening as well. All measuring and no listening, and vice versa, can make for a poor sounding system unless in the hands of highly skilled people; and a cynic might say that they are few and far between. 

  • Like 1

Share this post


Link to post
Share on other sites
5 hours ago, Metatron said:

What's the point? since if they did not agree, one of the systems would be faulty and you'd have no way to know which one.

I believe Dirac systems don't have a way to measure the achieved result after making a correction and so a separate measurement would potentially tell you something (noting that Dirac targets an average over multiple points and so a single point measurement wouldn't be a fair 'test'). Although having said this I'm still not sure how useful an independent measurement would be, in that presumably anyone using Dirac ends up comparing different targets and choosing what they like most.

(Independent measurements would also allow the direct signal to be isolated for those interested.)

Share this post


Link to post
Share on other sites
Super Dealer

It is always good practise to corroborate measurements, REW is a superb bit of kit.

Keith

Share this post


Link to post
Share on other sites
5 hours ago, MartinC said:

I believe Dirac systems don't have a way to measure the achieved result after making a correction and so a separate measurement would potentially tell you something (noting that Dirac targets an average over multiple points and so a single point measurement wouldn't be a fair 'test'). Although having said this I'm still not sure how useful an independent measurement would be, in that presumably anyone using Dirac ends up comparing different targets and choosing what they like most.

(Independent measurements would also allow the direct signal to be isolated for those interested.)

I don’t think it is essential to take post measurements after enabling Dirac features. It does a good job and it is easy to switch the filters in and out to make aural comparisons. 

I do, however, use REW to take measurements and see what effect Dirac has, partly out of interest and partly to assess whether anything can be improved and because I have the facilities to do so.

it’s probably worth pointing out that Dirac doesn’t just alter the frequency response as do some DACs advertised in this thread but also alters the impulse response for the better. That is the clever and IMO most important part of its filters. As I understand it the RME DAC, not to mention some current fave speakers do not do this.

Share this post


Link to post
Share on other sites
8 minutes ago, Camverton said:

it’s probably worth pointing out that Dirac doesn’t just alter the frequency response as do some DACs advertised in this thread but also alters the impulse response for the better. That is the clever and IMO most important part of its filters. As I understand it the RME DAC, not to mention some current fave speakers do not do this.

Not quite. Changing the frequency response changes the impulse response - they are two different representations of the same thing. The impulse response is the time domain representation and the frequency response shows the same information expressed in the frequency domain (with one related to the other mathematically by what is called a Fourier transform). BUT full frequency domain data includes not just the amplitude response that is usually plotted (how amplitude varies with frequency) but also the phase response (which shows how the relative phase, or timing, of different frequency components is related). I believe it is the phase response that Dirac Live pays more attention to than simpler systems, which will produce further improvements to the impulse response than just focusing on the amplitude response can.

I have been able to make clear improvements to the impulse response using a miniDSP 2x4 HD in conjunction with REW (which just uses the amplitude response). It is possible to also try to improve the phase response with the same hardware by the use of FIR filters but I have not spent time trying this yet.

  • Upvote 4

Share this post


Link to post
Share on other sites
Posted (edited)

Thanks for the clear post. Point taken; I was simplifying for clarity, and yes it is probably best not to describe components in isolation without reference to the whole picture, so to speak.

My point stands, and I think you agreed, that Dirac does have more effect on the impulse response than a simple parametric equaliser; at least that is what my experiments and measurements indicate. Either way, using Dirac in both a PC and miniDSP products has given me a useful improvement in “focus” and “clarity”, more effective than just using filters constructed in REW and applied in JRiver or miniDSP.

It is a complex subject and I am sure that others, including your good self, are more fluent at explaining it!

Edited by Camverton
  • Like 1

Share this post


Link to post
Share on other sites
46 minutes ago, Camverton said:

Thanks for the clear post. Point taken; I was simplifying for clarity, and yes it is probably best not to describe components in isolation without reference to the whole picture, so to speak.

My point stands, and I think you agreed, that Dirac does have more effect on the impulse response than a simple parametric equaliser; at least that is what my experiments and measurements indicate. Either way, using Dirac in both a PC and miniDSP products has given me a useful improvement in “focus” and “clarity”, more effective than just using filters constructed in REW and applied in JRiver or miniDSP.

It is a complex subject and I am sure that others, including your good self, are more fluent at explaining it!

Where I get unsure with Dirac is how it balances changes to improve the impulse response (which tells us about the direct sound) vs the room response curve (which adds in the effect of reflected sound). There is scope for 'fixing' the latter negatively affecting the former, and so there is the possibility for Dirac to make the sound in some sense worse. You're one of a few people here who have tried and liked Dirac though, whereas I have not heard it.

  • Upvote 1

Share this post


Link to post
Share on other sites
Super Wammer
21 minutes ago, MartinC said:

ou're one of a few people here who have tried and liked Dirac though, whereas I have not heard it.

Tony J and Bencat both talk highly of Dirac, when used with their mini dsp units.

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, MartinC said:

Where I get unsure with Dirac is how it balances changes to improve the impulse response (which tells us about the direct sound) vs the room response curve (which adds in the effect of reflected sound). There is scope for 'fixing' the latter negatively affecting the former, and so there is the possibility for Dirac to make the sound in some sense worse. You're one of a few people here who have tried and liked Dirac though, whereas I have not heard it.

I suspect this is a closely guarded secret. It would be interesting to know though.

Share this post


Link to post
Share on other sites
1 hour ago, greybeard said:

Tony J and Bencat both talk highly of Dirac, when used with their mini dsp units.

I think they are both very knowledgeable about Dirac; they may even be able to explain it better than me! I have used Dirac as a PC programme with JRiver - bit of a pain because it is all but impossible to reliably get it to autostart when a PC is booted and with a miniDSP DDRC-24. I have recently purchased a miniDSP SHD to act as pre, crossover to subs and Dirac processor. Much easier to use as it has a display to show Dirac status, preset, and input - Nice bit of kit with flexible connectivity which allows output to ones preferred DAC as well as having analogue output to a sub(s).

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.