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Sub Timing/Phase Adjustment Procedure

2K views 15 replies 4 participants last post by  theJman 
#1 ·
First off, I'm not even sure I need to ask the questions that appear below. I think the purpose of time-aligning a sub is to smooth out the frequency response in the crossover region. I also think that auto EQ like Audyssey and Dirac do this for you. But if using REW, I think it's a manual procedure, correct?

I know it's onsite somewhere, but I can't find any info on how to time-align a sub using REW in a multichannel system. Some threads have suggested using the RTA function in REW, but stop there. Other threads refer to a group-delay method that's been described as complex and non value-added. Rhetorical question: "Who's right?"

If this has already been covered before, can you please link me to the right thread?

Also, it would be very helpful to have a birds-eye view of the process. Just an outline of the major steps would be nice!
 
#2 ·
First off, I'm not even sure I need to ask the questions that appear below. I think the purpose of time-aligning a sub is to smooth out the frequency response in the crossover region. I also think that auto EQ like Audyssey and Dirac do this for you. But if using REW, I think it's a manual procedure, correct?
Yes, time alignment is important to achieve smooth response through the crossover region. Strictly speaking, REW has nothing to do with that. It only shows you the results of the Audyssey or Dirac auto-set up to confirm it’s been done right.


I know it's onsite somewhere, but I can't find any info on how to time-align a sub using REW in a multichannel system. Some threads have suggested using the RTA function in REW, but stop there. Other threads refer to a group-delay method that's been described as complex and non value-added. Rhetorical question: "Who's right?"
RTA, group delay, etc. – these things are only useful or needed if you intend to do the set-up manually. If your equipment has Audyssey or Dirac, use it and you won’t have to worry about any of this. :T

Regards,
Wayne
 
#3 ·
The term "time align" is generally associated to the adjustments that ensure the output of every speaker and subwoofer reach your ears simultaneously. The most effective way to achieve that manually is to use the 'distance' setting in your AVR or, as you've noted, let the auto EQ system (Audyssey, et al) do the work for you.
 
#4 ·
Yes Wayne and Jim, I'll let Dirac handle it for now but there's only one problem. My Emotiva XMC-1 has a fixed house curve, which is too bright for my taste. A user-adjustable firmware version is scheduled to be released "soon". The XMC-1 also has REW PEQ capability, which I've set-up. I swap back and forth depending on source material.

Dirac does a subjectively better job than REW at recreating a convincing sound field, but it seems bass-shy and treble heavy even after many measurement trials and mic patterns. While I wait for adjustable house curves, I'd like to improve my basic REW skills to get better results. I'm sure the good people here will help me interpret my graphs and keep me on the right path!

Thanks for the input and helping me realize that phase correction, impulse response, and group delay plots are out of my league just yet.
 
#14 ·
Yup, it's official. Found a setup function which is supposed to lock out (in?) all changes. Made no difference. The tone control settings were lost on power-down. Not complaining, just saying. I haven't explored or learned all the unit's functions yet, so I'm going to give it benefit-of-the-doubt for now. My pre-pro has three layers of lock-out capability, and two different power-cycle strategies involving front and rear switches. Maybe one of those combinations (permutations?) works. Maybe I'll get around to experimenting some day. :nerd:

:ponder: Wait, I know! I'll expend energy on multi-channel setup and my REW learning curve instead!

Please understand, I appreciate the help all of you have given me here. I will follow your advice to either program in speaker distances, or let DRC handle it. :wave:
 
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