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In Reply to: vista time phase correct posted by tz7 on January 20, 2007 at 19:52:12:
There has been an extensive discussion about the room correction features in the new Vista audio stack on AVS forum. I assume there is a policy against cross posting but a couple of Microsoft people from the audio team have created that discussion so you can get the answers from the horses mouth.As far as I know the Vista stack does time alignment and frequency adjustments. I don't know about any phase corrections. The whole stack uses 32 bit floats internally.
Cheers
Follow Ups:
Thomas,Are you saying that the Stack is floating all incoming data???
Man why can't you guys just leave the samples alone.
thanks for the response... I've read that forum and it say it does "time delay" to align the speakers...but i think what I am looking for is some similar to the deqx software that within a speaker adjusts the timing so each speaker is time correct. Do you know if it does this?? I asked over there but haven't heard back.
Tz7:If you want to do DEQX level room/speaker correction you're going to need to either get into Acourate/BruteFir or Denis Sbragions DRC using one of many different convolvers.
You're also probably going to want to go the multi-amp route doing your crossovers in the digital domain to get into the league of the DEQX. You *can* correct a full range passive loudspeaker, but better results can be had with the DSP/active or even conventional active route. A good DSP based method for this is the Thunuea Allocator / Phase Arbitrator route. Even then, the DRC process is not intuitive or step by step, and requires a fair bit of know-how with measuring techniques, crossover design, and interpretation of measured results. There are things one can "tweak" along the way such as spline curves for response shaping, and different "strength" of DRC algorithms to choose from. It's really a science experiment more than a process you just "do" - it's a labor of love for sure!
Although there is a step-by-step manual available for the Sbragion approach, the end result has a lot to do with speaker placement, room geometry and treatments, and the users ability to take measurements, record sine sweeps, and perhaps most important, the ability to know when a good result is obtained! This is not really a good thing to apply "trial and error listening tests" to - you also need to be able to interpret the results both objectively and subjectively. Too much in either "direction", and you'll lose sight of what you are trying to accomplish.
This is what has me sort of luke-warm on the process. It's a powerful tool, but you need to know it's workings and limitations and stay within those confines.
The money you pay for the DEQX is not just for a piece of hardware - it's for a solution that just about anybody can set up. You don't need to be a speaker designer to set up a DEQX. I believe you do not need additional measuring software with the DEQX as well. Acourate "is" the measuring software and its very comprehensive, but you need BruteFir to implement it. Sbragions DRC requires third party measuring software, and convolver plugins to make the end product work. Both are very powerful in the right hands...
You do, however, have to have a fair bit of technical know-how to properly implement Acourate or Sbragion's DRC.
And no, Windows Vista will not come close to what these extremely powerful (but complex) solutions will do. Then again, in windows you basically put a mic in the room and click a checkmark in the "room correction" box! ;) What do you want for that kind of simplicity?
I think Windows DRC is akin to the kind of room correction / room setup solutions that many mid and hi-end hometheatre solutions have today. Great for calculating listener to speaker delays, and some minor equalisation, but not powerful enough to start correcting time-phase errors.
thanks presto....is the bottom line even with deqx to get time phase correct you have to bi amp? I have maggie 12s and I don't think they bi amp.
T,I have the MMGs, and you can mod your 12s to be able to biamp and use the deqx.
Here is a link to how I did my MMgs.
Tz7:Sorry I gave that impression - my bias towards bi/tri-amping came through loud and clear there... :o)
You can do two things with the DEQX - you can do speaker correction (which requires bi/tri-amplification) and room correction, or just room correction.
The "room correction only" option has only stereo outputs. The speaker and room correction option has six outputs because it functions as a digital stereo three way active crossover.
If you speakers are not "bi/tri-amp" friendly, you can always do the room correction only option. However - it's aweful tempting just to 'at least' bi-amp so that you can perfectly time align a sub with main speakers.
There are some (happy) DEQX users roaming about here - put a post about DEQX in general and see who chimes in.
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