we're not trying to T/A the rear speakers to be in alignment with the other speakers in the car. we are trying to get the effect of a larger space with diffuse, filtered reflections. same as what you get in a room with a nice analog sound system. in a car, reflections are hard to come by due to standard driver spacing. the result is an effect where you are in a semi-anechoic chamber where everything is in front of you and nothing is behind you. in the 2 channel home audio world that only happens outside.
the home audio scene is on a different planet compared to car audio. i've heard home systems costing over $100k, ridiculous. but even those systems were in a room and that room had reflections - i.e. information from behind you. granted, if you're listening to Wilson Audio speakers they are very specifically placed based on the room.
point is, in a car, some people like the sensation that they aren't in a car. funny, i know. with speakers in the kicks you get better driver distances (relative to the seated position) but you also have sources below your feet. that is not something home audio has to contend with.
so, in order to have a "room" you have a few options. 1. buy a van and use apillar mounted mids/tweets. 2. buy a car and try to incorporate rear fill.
rear speakers are rarely properly used for "rear fill". i have long been a proponent for no rear speakers at all due to the added complexity and processing power required to make it work. fact is, when properly executed the results are amazing. a sound stage can increase in depth and width if properly executed rear fill is used. the problem is that it's very difficult and stock locations are rarely useful.
we all like something different. we shouldn't lambaste someone for liking something else. if someone wants to execute rear fill, more power to them. maybe you don't like it, STFU because it isn't your car or your money. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
all that said, i'm not set on the magical 20ms. I have been playing with settings on my H701, the rears are on the center out and the H701 is in 3ch PCM mode. I can't use the rear outputs because my front stage is 3-way active. luckily, i don't mind a mono rear fill, once it is properly eq'd, filtered, and delayed.
if you delay the rear speakers to the time setting relative to the driver distance separation - you end up with an image that is in your lap. it's not desirable. as the rear speaker information arrives at a later time, the sound stage is pushed away from you. but once you move away from perfect alignment you also start encountering phase interference. it's a delicate balance.
simple is better. mobile audio systems are far from "simple" way to many separate parts and pieces with horrible speaker locations and environments. i don't build car audio systems trying to get the most accurate representation possible - that is what 2 channel home audio is for. i invest time and money in car audio because i like listening to music while i drive. simple as that. i go the extra mile because it's a hobby that i enjoy and i like the challenge of working on a sound stage in such a fvcked up environment. but mostly, i like music.
