Now to get the ball rolling and dig into the good stuff
This tutorial will start to cover general theory into system design.
Running a lower crossover point
I'm doing this one first because this one benefits those that plan to install in stock spots. This tutorial applies to 2 way applications. A typical vehicle will have 6.5" or 5.25" midbass drivers in a low door location. When you are attempting to design a speaker system that will work from factory locations, the first thing you have to take into account is the extreme off axis nature of a factory door location. The drivers side door is the worse of the two, often being 60 degrees or even more off axis to you. The passenger side mid will usually be off axis, but less so than the driver side.
The main benefits
You are limiting your midbass drivers to a region where they retain good dispersion. This is critical for getting good imaging from off axis locations such as factory door spots. From there the tweeter takes over, which has much better dispersion than a midbass driver would within that intended range.
Car doors tend to create reflections, aka standing waves. Not really just car doors, but enclosures in general. This can especially be a problem in the upper midrange region and a lower crossover point can help combat some of these problems.
The lower the crossover frequency, the less lobing is an issue. Lobing is a fairly complicated phenomenon and is better defined as a form of destructive interference. To keep this part of the tutorial simple, as the crossover frequency becomes higher the problem worsens. The effect of lobing is cancellation at different axises. As a side note, generally the shallower the crossover slope, the more severe the effects of lobing.
The basic summary is that lower crossover points allow you to get better off axis performance from a speaker system, and that is critical when you're talking about installing speakers in factory spots.
In case you're wondering which conventional car audio manufacturers tend to show this design theory, you'll typically find it from mostly the more expensive offerings of high end manufacturers:
Dynaudio
Morel
DLS (2 ways)
Rainbow Audio
SEAS
Focal (some cases)
MB Quart
Boston Acoustics
Keep in mind those are just a couple of examples.
The tradeoffs of this design
The limitation really ties in to a statement that I've made numerous times
:
Most car audio equipment sucks
In this case, the tweeter is really the limiting factor. A wussy compact neo dome isn't going to do any justice with a 2khz acoustic crossover point, much less a 2khz electrical point. They don't have the motors, the rear chamber, or the flange design to cut the mustard. There are some notable compact car audio tweets that do a pretty good job at it, but none I've seen can match the performance of a well built large flange tweeter. It boils down to the fact that it's easy to build a tweeter, but extremely difficult to build a good one. Mounting a 1.5" deep tweeter with a 4" flange isn't on the priority list of most. Even if you can, the lower the crossover frequency, the more you limit the high volume capability of a tweeter. Excursion requirement quadruples with every decreasing octave. Meaning a tweeter crossed at 2.5k will have to move 4x as far as one crossed at 5k. With that comes added distortion, especially at high volumes.
One of the bigger tradeoffs is that if you want a tweeter to perform better down low, that means a larger tweeter. Many of them are 25mm (1") or 28mm (~1 1/8") designs. When you use a tweeter this large and put it off axis, top end dispersion typically suffers.
Another tradeoff is that you're crossing over in a more "critical" frequency range. Our ears are most sensitive in upper midrange and ideally we'd have one driver performing the critical region. Some, including myself, question that argument at times since our ears are most sensitive at 4khz, and most 6.5" midbasses don't sound great running that high to begin with. Or at least they don't sound great compared to what could be covering that region- a good tweeter or midrange.
Now to get the ball rolling and dig into the good stuff :D This tutorial will start to cover general theory into system design.
[b]Running a lower crossover point[/b]
I'm doing this one first because this one benefits those that plan to install in stock spots. This tutorial applies to 2 way applications. A typical vehicle will have 6.5" or 5.25" midbass drivers in a low door location. When you are attempting to design a speaker system that will work from factory locations, the first thing you have to take into account is the extreme off axis nature of a factory door location. The drivers side door is the worse of the two, often being 60 degrees or even more off axis to you. The passenger side mid will usually be off axis, but less so than the driver side.
[i]The main benefits[/i]
You are limiting your midbass drivers to a region where they retain good dispersion. This is critical for getting good imaging from off axis locations such as factory door spots. From there the tweeter takes over, which has much better dispersion than a midbass driver would within that intended range.
Car doors tend to create reflections, aka standing waves. Not really just car doors, but enclosures in general. This can especially be a problem in the upper midrange region and a lower crossover point can help combat some of these problems.
The lower the crossover frequency, the less lobing is an issue. Lobing is a fairly complicated phenomenon and is better defined as a form of destructive interference. To keep this part of the tutorial simple, as the crossover frequency becomes higher the problem worsens. The effect of lobing is cancellation at different axises. As a side note, generally the shallower the crossover slope, the more severe the effects of lobing.
The basic summary is that lower crossover points allow you to get better off axis performance from a speaker system, and that is critical when you're talking about installing speakers in factory spots.
In case you're wondering which conventional car audio manufacturers tend to show this design theory, you'll typically find it from mostly the more expensive offerings of high end manufacturers:
Dynaudio
Morel
DLS (2 ways)
Rainbow Audio
SEAS
Focal (some cases)
MB Quart
Boston Acoustics
Keep in mind those are just a couple of examples.
[i]The tradeoffs of this design[/i]
The limitation really ties in to a statement that I've made numerous times :D :
[b]Most car audio equipment sucks[/b]
In this case, the tweeter is really the limiting factor. A wussy compact neo dome isn't going to do any justice with a 2khz acoustic crossover point, much less a 2khz electrical point. They don't have the motors, the rear chamber, or the flange design to cut the mustard. There are some notable compact car audio tweets that do a pretty good job at it, but none I've seen can match the performance of a well built large flange tweeter. It boils down to the fact that it's easy to build a tweeter, but extremely difficult to build a good one. Mounting a 1.5" deep tweeter with a 4" flange isn't on the priority list of most. Even if you can, the lower the crossover frequency, the more you limit the high volume capability of a tweeter. Excursion requirement quadruples with every decreasing octave. Meaning a tweeter crossed at 2.5k will have to move 4x as far as one crossed at 5k. With that comes added distortion, especially at high volumes.
One of the bigger tradeoffs is that if you want a tweeter to perform better down low, that means a larger tweeter. Many of them are 25mm (1") or 28mm (~1 1/8") designs. When you use a tweeter this large and put it off axis, top end dispersion typically suffers.
Another tradeoff is that you're crossing over in a more "critical" frequency range. Our ears are most sensitive in upper midrange and ideally we'd have one driver performing the critical region. Some, including myself, question that argument at times since our ears are most sensitive at 4khz, and most 6.5" midbasses don't sound great running that high to begin with. Or at least they don't sound great compared to what could be covering that region- a good tweeter or midrange.