Opinions on 2 General Statements

[beak81champ]

While reading/researching for my system, I came across 2 statements that I thought were very interesting, and wanted other opinions on:

1) The best speaker design in factory locations, will sound better than poor speaker design in the best install within a standard vehicle.

2) If the driver isn't going to beam within the bandwidth you are running it, there is no need to aim it.

What say you?

[slade1274]

My take based on what I experience/understand:

While reading/researching for my system, I came across 2 statements that I thought were very interesting, and wanted other opinions on:

1) The best speaker design in factory locations, will sound better than poor speaker design in the best install within a standard vehicle.

This is a catch 22 situation based on what factory locations you have in your vehicle. That being said- as a general statement I would claim the exact opposite. A properly installed basic driver will (remove poor, you can get decent drivers for $15) outperform the "best speaker design" in a poor location.

2) If the driver isn't going to beam within the bandwidth you are running it, there is no need to aim it.

What say you?

Somewhat right.... but not more than 60^ offset- and it isn't necessarily linked to the beaming frequency. FR plots (frequency response) are generally shown at varying degree of offset from the driver. If you see the FR tail off in the upper frequency ranges as you get at greater angles- that's where you don't need to worry as much about aiming. It gets even easier with lower frequencies as they are not directional- my sub is in the trunk and midbass are under the front seats- works great.

[dejo]

I will agree with what slade stated

[papacueball]

As I understand it, the off axis roll off is caused by comb filtering, and is the other side of the coin, so to speak, to beaming, and the frequency where that starts to occur is a function of cone size. The bigger the speaker, the lower the frequency where beaming/comb filtering/off axis roll off comes into play. There is math involved, and a chart somewhere that lists driver size and frequencies somewhere.

[slade1274]

Comb filtering is completely different and only distantly related to the conversation. My understanding is that comb filtering is usually an issue with opposing drivers effectively "canceling" each other out at certain frequencies- much like using noise to cancel noise in those fancy headphones. I can happen with a single driver by reflections but is most common with another driver. The effects can be changed with time allignment or phase shift; adjusting the arrival time of the cancelling frequencies so they don't cancel.

[beak81champ]

But when the FR tails off, that is where he is saying you would have the next driver crossed below that, correct? So, off axis should not matter, except in the case of a tweeter, since it is the very top end...

Do I even understand crossovers correctly? high pass is where a sub cuts off up top, low pass is where a tweet takes over from the mid, and band pass specifies a bottom and top cutoff frequency for midbass and midrange...heck, I might not even be understanding what I am reading!

[BigAl205]

Nope, you've got it backwards. Low pass is where the low frequencies are allowed to pass and all else is filtered. High pass allows higher frequencies to pass, and bandpass is a combination of both, where only a certain band of frequencies is allowed to pass.

[papacueball]

Comb filtering is completely different and only distantly related to the conversation. My understanding is that comb filtering is usually an issue with opposing drivers effectively "canceling" each other out at certain frequencies- much like using noise to cancel noise in those fancy headphones. I can happen with a single driver by reflections but is most common with another driver. The effects can be changed with time allignment or phase shift; adjusting the arrival time of the cancelling frequencies so they don't cancel.

My apologies for misusing the term 'comb filtering'. How about phase cancellations resulting from the interaction of waves originating from points on the cone that are not the same distance from the listening position?

[beak81champ]

So, what are we saying? Do you guys think each driver (except for subs) needs to be at the most 60 degrees off axis, and closer to on-axis the higher the frequency each is assigned? Aren't subs omnidirectional? If this is what we are saying, then I am thinking:

My subs will be downfiring under my rear seats
8" midbass will be in the doors aimed right above the opposite window
6.5" will be in the kick panels aimed at opposite headrests
4" midrange + 1" tweets in or around the base of the a-pillars, again aimed at opposite headrests

Does this present any instant issues that come to mind, or would this be an appropriate starting point to build door pods, a-pillar pods, and fiberglass kick enclosures?

[BigAl205]

That looks about perfect to me