- Thread Starter
- #61
Thanks, pretty interesting. I'll give it a try. Still not sure if I've got enough math background.
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Dirac > Audyssey XT32 ... Sure, Always?
- Thread starter Gedeon
- Start date
Yep, wrong assumption. Filters that you will create are being processed by convoltion engine. Think of it as additional signal processing box you have inserted in a signal chain causing delay of the whole signal. With stereo music reproduction this has no particular importance but if this audio signal would be accompanied with video than you will have lipsync issues as audio will be delayed.
I'd be happy to. The confounder is, of course, that Dirac cannot be used as a standalone, so if the amp containing it is resampling (I don't know if it does), changing the data rate of the input signal will likely have no effect.
- Thread Starter
- #64
A last question (for today) about taps and sampling rates
Let's say we have the same/algorithm engine to design a FIR filter to be used mainly for 48khz sources, using the same set of measurements.
Which could be better (theorycaly) better/more precise ?
- 512 taps without resampling (48khz)?
- 1024 taps resampling to 192khz ?
Let's say we have the same/algorithm engine to design a FIR filter to be used mainly for 48khz sources, using the same set of measurements.
Which could be better (theorycaly) better/more precise ?
- 512 taps without resampling (48khz)?
- 1024 taps resampling to 192khz ?
One more potential confounder- I put the amp on my test bench today and it seems to have about a 50ms delay irrespective of what Dirac or other DSP settings are chosen, as well as whether analog or digital inputs are used. This was a bit unexpected, and I'm digging in to see what that's all about...
The 3ms difference between Dirac on and Dirac off also persists.
The fact that there is a 50ms delay with analog inputs may lead to theory that the signal path between analog input and amp output is not fully analog..
Ya think?
See, this is why negative feedback can't work!
- Thread Starter
- #70
Bumping this thread because I'm started to think, after more readings, that Dirac tries to deal with phase issues related with each speaker independently.
However those issues may appear if your speakers are too close to walls/hard surfaces or their design/cabinet isn't very good with filters/resonances/... their directivity/room position isn't near to be optimal, etc... Obviously difficult/small rooms could also benefit more from Dirac approach than Audyssey due to reflections.
What do you think ?
However those issues may appear if your speakers are too close to walls/hard surfaces or their design/cabinet isn't very good with filters/resonances/... their directivity/room position isn't near to be optimal, etc... Obviously difficult/small rooms could also benefit more from Dirac approach than Audyssey due to reflections.
What do you think ?
Do you know for sure Audyssey does not do that independently too? It is an interesting point to me as I think it should be, better be unless they have good reasons not to. I can always ask Audyssey, it seems that they do response to questions quickly.
On another note, the mention of negative feedback "can't work" puzzles me.
- Thread Starter
- #72
Maybe It does, maybe It doesn't. Just trying to guess which truly Dirac adds.
A phase issue could be detected and partially fixed with group delay techniques and IIR filters if I'm nota wrong.
It could also explain why some users in certain rooms with certain speakers don't hear great differences between Audyssey XT32 and Dirac, while other ones do hear certain improvements, mainly in "clarity".
We also must remind that Dirac started with car-eq algorithms with big brands. In such "rooms" reflections and phase issues are really hard to deal with. On the other hand, small phase issues seem really difficult to perceive. So with "good" rooms and speakers, Dirac improvements could be less useful.
But just guessing.
I would think that Audyssey does check for phase. Otherwise I wouldn't get those annoying messages to check the wiring to my speakers. Yes they could be useful, but I'm more careful than that.
- Thread Starter
- #74
Audyssey checks phase inversion between different speakers (and usually doesn't do It very well). As far as I know Audyssey doesn't try to fix "resonances/crossover" and similar issues applying intra-channel/speaker delays, but reducing amplitude for a frequency range.
I'm pretty curious about if Dirac tries to solve those.
With regards to Audyssey EQing "flat": Audyssey by default enables Dynamic EQ, which means they also likely have created target curves that assumes you will do that. And then the end result is not flat, but a nice downwards sloping curve - with a full sound.
So disabling Dynamic EQ and the complaining that the curve is too flat, is more of a user error / misunderstanding of how this works.
So disabling Dynamic EQ and the complaining that the curve is too flat, is more of a user error / misunderstanding of how this works.
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They need to update the post links to account for the new AVS forum software.
I think Audysey downsamples the subs. In that way they can correct also down low with a low number of taps.
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