Originally Posted by gbreda
After time aligning my 2 subs with each other with Quick Sweep and then REW prior to ARC cailibration, setting the distance in with REW along with my center speaker resulted in 16 ft when physically they are only 10 ft. I always check and reset the distance after ARC to tweak a little if needed.
Originally Posted by adya11
These are the best 3 i could come up with .
I just cant keep moving these huge subs around lol
the bright orange/yellowy measure is both subs inside of main speakers front of room facing MLP
Thats where theyll currently stay for now i think
Opinions on which looks best out of the 3?
* Also, I keep hearing how useful MiniDSP is in EQing subs.
What benefit would a MiniDSP have over ARC? Isnt it basically the same thing?
ARC will EQ peaks and dips. using Minidsp will EQ peaks and dips??
I am just guessing what has gone wrong here, but it seems that there is some misunderstanding about what time alignment of a subwoofer means, and how it can be measured and adjusted. I started this reply earlier, but ran out of time (church) and now Bittermidget has posted a very useful response that I think gets at what may be wrong. Since I started my reply, I’ll try and explain what I think is going wrong with your process at perhaps a more basic level.
When you run ARC, it measures the various speaker frequency responses and calculates PEQ values to optimize that response for the various speakers. It also analyzes the best crossover frequency so that the various speakers, e.g. the front speakers and the subwoofer(s) play together nicely in terms of their measured frequency responses. It then loads all these values into the AVM 60 – a wonderful almost fully automated process.
What is missing is that all the ARC calculations assume that in the crossover region the woofers in the front speakers and the subwoofer are in phase. When a front speaker is pushing air, then the subwoofer should also be pushing air so that when their respective sound fronts arrive at the seating positions, they reinforce each other. If one speaker is pushing and the other pulling air, then the sound front from the two speakers will interfere with each other and cancel the sound rather than reinforce the sound.
Getting all the speakers to deliver their sound in a coherent manner with the other speakers is what time alignment is all about. Entering the speaker distance into the AVM 60 is the way you adjust for the fact that speakers that are farther away from the listening position need a head start to get their sound time aligned with a speaker that is nearer. With speakers, other than subwoofers, simply entering the measured distance is all you need to do, but for various reasons, subwoofers can act like they are farther away than the tape measure would indicate. And that is why we need to use REW measurements to get the subwoofer distance correct and the subwoofer playing nicely with the other speakers in terms of timing or phase.
There are a couple of ways of doing this using REW, first, looking at the frequency response of how a front speaker AND the subwoofer’s COMBINED frequency response varies with the subwoofer distance, and second, using the impulse response tab. I think what you may have been doing wrong is either running frequency response measurements as a function of subwoofer distance using only the subwoofer, or with the level of the subwoofer so high that its response dominates the overall frequency response measurement. If only the subwoofer is playing, you can’t measure how it interacts with any other speaker – hence no change in the measured response.
So, pick a front speaker in REW, either the center or the front speaker closest to the sub, and run the measurements as a function of subwoofer distance as set in the AVM 60. DO NOT select a speaker AND the sub in REW as that doubles the sub response and might cause it to dominate. Just chose a speaker and REW will send a full range signal to the AVM 60 and the AVM 60 will send the right frequencies to the sub as per the crossover set by your ARC measurements. Choose the distance with the flattest response in the crossover region.
The second method is to use the impulse response tab with a measurement of the sub only. In this case it will measure the time response of the sub relative to the reference timing pulse from the speaker you are using for the timing reference in REW . Even though you are only sending signal for measurement to the sub, it is looking at the timing of the sub’s response relative to the timing pulse from the reference speaker. So again, it is looking at how the two speakers are time aligned. Read the REW guide as to how to do this. This is how I set my sub distance as it is much more straightforward. Hopefully I find the time someday to also look at the frequency response as a function of distance, as I would be interested in how they compare.