hello sir, this is an awesome build thread to follow. I have a scion tc so i have found this very helpful. My question is what did you aim the tweets at? do you have a picture of where you aimed the laser pointers at?
no pic of where we aimed them, we did aim for the middle of the top of the rear window. once there we can rotate for aiming higher or lower. we have also experimented with a few heights. with tweeters, experimentation is good, but aiming can be figured out ahead of time.
there are two ways to approach tweeter aiming.
1. aim them at the rear of the car - this puts them more on-axis with each seat. using processing and presets you can tweak level for each so you get a good sound stage. remember that high frequencies (>3kHz) are located based on intensity (level) so the louder one will pull the soundstage toward it. some cons are required level adjustment and adverse affect on head related transfer function (HRTF). you can get a reflection off the nearest window that can help HRTF and also widen the soundstage (if the rest of the system and processing coincides).
2. aim them at the opposite c-pillar - this puts the tweeter slightly off-axis with the nearest seat and on-axis with the opposite seat. great approach if you can't control level on the tweeters separately or easily. also a good approach for a car setup for two-seat judging. some cons are a reduction in high frequency detail/response in the nearest tweeter, as well as a potential narrowing of the sound stage (depending on the other speakers in the car). the HRTF is well addressed thanks to the acoustic center and aiming from outside to inside (not aimed head-on). one downside is a reflection off the opposite glass (passenger tweeter sound bounces off driver window into driver's left ear), but since this reflection is delayed in time, HRTF is maintained - but level attenuation (R vs L) is not much different.
if your tweeter crossover point is below 3kHz, then T/A is desired on the tweeters as well. If you can maintain a higher tweeter crossover point, you don't need to T/A them. if you go for option
#2 then you don't need any processing on them other than a crossover. level is also addressed. That is what I do in my car with a 3-way front stage. my tweeters are on the same HU output channels as the mids, i just use an external active crossover. it works great. with a 2-way system you don't have the luxury of a higher tweeter crossover point if the woofers are door mounted - an off-axis woofer rolls off much sooner. one big advantage of kick mounted woofers/mids is aiming for improved high frequency response of the woofer, another advantage is reducing path length difference between left and right.
car audio is such a fun challenge when you look at acoustics. if you can visualize the propagation of sound waves and some of the interaction caused by specular reflections, then apply the concepts of IID, ITD, PLD, and HRTF, you can get a good idea of what is going on - which will help when designing and tuning the system. This Scion build is further benefited by the owner, who has a good critical ear and experience as a recording engineer - so he can tune by ear and make it perfect.
note: we are considering a HU upgrade to the 80PRS - mainly for the benefit of USB performance.
