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Old 09-13-2011, 03:22 AM
Evlengr's Avatar
Evlengr Evlengr is offline
Ukemi - that's how I roll
Location: MD
Join Date: Feb 2007
Posts: 4,252
Mein Auto: 2013 Audi S4 2010 MT MCS
Originally Posted by deafwish View Post
In fear of looking like I'm trying to prove you wrong - your above statements are not entirely true.
All the factors in having ideal sound reproduction in a car is to generate the imaging & complete sound spectrum of a live recording/ event.
Putting the same speakers in the back of your car as the front will give you too strong a 'rear stage'.
When was the last time you went to see a concert/ band or even orchestra & had the sound coming from behind you?!
A strong front stage is paramount in any audio build - regardless of the environment it is installed in (home, live, car etc).
Rear speakers are called 'rear fill' & they are designed for exactly that.
In just about every install I do, I either dis-connect the rear speakers or leave the stock ones connected - but faded out.
In a perfect world, you want the rear speakers to only be audible by the rear passengers.

You are correct in that bass frequencies (<100Hz) are non-directional.
The sound emitted from the under seat mid bass is NOT subsonic - as it is not a sub woofer.
Mid Bass speakers are designed to reproduce frequency ranges of between approx 100Hz & 250Hz and those frequencies are directional.
Mid range speakers (like our door mounted 4" drivers) typically reproduce frequencies around 300Hz to 3.5KHz and is even more directional.
Tweeters are the most directional frequency and have a dramatic effect on imaging in a car.
Go have a listen to a passive 3 way system and cover the mid bass with cardboard. You will instantly know what I'm talking about!


You seem to think you have something to prove here. Fine. I have been in the music industry for over 37 years. I have worked directly with Boyz II Men doing sound recordings, Jazzy Jeff and Wil Smith and I went to competing high schools and ran DJ businesses while there, built sound systems for clubs of over 5000 people, opened for both Rob Zombie and Moby, The Chief Engineer for 5 FM and 3 AM radio stations in Washington DC witha listener base of about 3 million, worked on the design team for Radio Disney to name but a few things. I am currently an engineer for Sirius/XM Satellite radio systems and work on their streaming initiative

Btw if you can hear your subs generated from the direct back then your timing is set wrong for the release times. If you want to get really picky, my processor has different macros to deal with temperature differences that can impact sound reproduction by slwoing certain frequecies down from acoustical masking.

The advice I give is paired down to more practical levels for people. Part of my job here at Sirius/XM is to translate from Engineese to English. If you want to take this off line and talk about things through PM thats great. I can share with you the idea of controlling attack and release times in a small environment like a car with processors and/or give you the schematics to build a crossover to control bandpass. And love to hear some of your work as well. Sounds like we probable have some of the same ideas, but just like to convey them differently.

I agree that the speakers under the seats are not sub-level bass. If you go back and read my posts you will see that mentioned repeatedly. Telling people to put full range speakers under the seat is bad advice as the audio spectrum they produce will get lost (Your best bet is to restrict the audio to 125HZ to 800hz to those speakers). I have already tested this with digi-analyzer. Here is a basic diagram of what I have done with my vehicle and recommend if you want to improve your system with out altering the physical or electrical attributes of an X3.

If you want to have a pissing contest then you win. I am not here for that.
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Last edited by Evlengr; 09-13-2011 at 04:19 AM.
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