Originally Posted by mthomas47
This is an interesting thread, and I am enjoying learning more about ARC Genesis. It sounds very cool! I started by reading the most recent posts and have since been reading the thread from the beginning. I think I can explain why the bass might sound relatively more muddled (compared to boosting only the subwoofers, below a certain frequency) with the Deep Bass Boost affecting all of the speakers and not just the subs.
AVR crossovers use high-pass filters and low-pass filters to provide more gradual transitions from speakers to subwoofers. Those filters don't act as brick walls, abruptly cutting-off the sound. They just gradually attenuate the sound. That way, we aren't suddenly hearing the subwoofers cut-on, and the speakers cut-off. Typically, the high-pass filter for the speakers reduces the volume by 12db per octave. So, implementing an 80Hz crossover would gradually and symmetrically roll-off the volume of those speakers by 12db at 40Hz.
But, if you are boosting all of the channels by 6db at 40Hz, you are adding back 6db at that specific frequency. Now the speakers, which were getting softer from 80Hz down, are suddenly louder again, and a 6db increase in volume at 40Hz could make enough difference to be audible. That would especially be the case if you were able to compare that sound to a completely different approach, such as the application of a house curve added only to the subwoofers.
Frankly, I think that some speakers might distort a bit if they were playing 40Hz frequencies only 6db lower than they were having to play 80Hz frequencies, and the muddled sound could be that distortion. Of course, that would depend somewhat on the master volume level and the native content. The louder the volume level, the more potential distortion. (There can also be some potential phase issues involved when speakers and subs--particularly ported subs--play the same frequencies.)
Low-frequency distortion tends to sound somewhat boomy or unclear, unlike high-frequency distortion which sounds screechy or piercing. A somewhat unclear or cluttered bass sound could be a pretty good description of low-frequency distortion. Boosting channels by 6db at 40Hz could actually be considered somewhat counterproductive to setting 80Hz crossovers for those channels in the first place.
I don't want anyone who is currently enjoying that feature to suddenly become self-conscious about it because of my post. But, it occurs to me that since Anthem seems to be pretty cutting-edge with their updates, it might be worthwhile for some owners to contact them about allowing users to choose whether or not to apply the Deep Bass Boost to all of the channels, as opposed to applying it only to the subwoofers. Or, ARC could just let that feature affect only the subwoofers, by default. That would be an even better solution.
I hope that no one minds me commenting on this.
Welcome to this thread and as usual your opinions are welcome and helpful. It's funny how I learn, forget and have to re-learn. I know better than my comment to Legairre would suggest. Of course, the crossover is not a brick wall. Thanks for the reminder.
My temporary ignorance still doesn't change the experience I've been having. I've struggled for the last year with my 4 sealed subwoofers and ARC2. Many, many times I'd tell my long-suffering wife that this is now perfect, only to wake up the next day dissatisfied. You, Mike, provided essential advice to me during this period. However, with ARC Genesis, my experience has been completely different. From the first, I was startled at the difference in the clarity of the bass. With ARC2, I was always adjusting the bass in a 10 db range according to the material.
Male voices, in particular, represented a challenge. With the most recent Genesis calibration, before which I fixed various issues I mentioned a few posts ago, I finally feel I have achieved what I've been looking for. With a deep bass boost of 6 starting at 40hz, I have only had to change to a profile with no bass boost once. Other than that one instance, my bass is powerful and clear in my large room with 4 SB16Ultras. I cannot hear any muddiness or boominess. I can't explain why I'm hearing what I am, only that I am.
Is it possible that some of the differences in what we're hearing is that I have sealed subs and perhaps, those with ported are getting more muddiness at 40hz? After all, I think ported are 3 db louder at 40hz and 6 db louder at 32hz. So, for ported, the deep bass boost would be that much louder than for my sealed. Just a thought.
Before Genesis, I had been following various processor threads considering changing to Dirac because of the frequent indistinctness of dialogue, always with male voices. Genesis has eliminated that problem in my system.
I don't have a minidsp in my home theater for comparison purposes. I would probably try it just to contribute to the team, but for my purposes, my relatively long search and struggle is over.