Hi/Low Pass + Crossover Tuning Question

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Theoretically, if you have your sub woofers low pass cut off at 300hz, should the next set of speakers start at 300hz and above or is there a a certain amount of overlapping frequency that you should have?

Or is this just a dumb question and you tune by ear anyway? lol...
 
If your subs go up to 300 Hz, they are better called woofers.

dave

That is why I said theoretically, because without going into my trunk to find out what what my settings are actually at, I have no clue the exact numbers. :p I am just curious as to the tuning aspect.

Also, another question. If a speaker's response is say 55hz, how effective is it actually at 55hz? Should I have the cut off at 55hz or higher. Again, is there any general rule of thumb to follow with frequency cut offs?
 
Speaker response specs are often given by a graph and include the type of environment and the type of enclosure. These are possibly the best indication of the speaker's frequency response but the response in your enclosure and in your vehicle will change the frequency response significantly.

If you use the same crossover point for the high/low speakers, there will be overlap but it's generally insignificant because the output of the high/low speakers at the crossover point is reduced. If there is a gap in crossover frequencies between the high and low speakers, there may be a hole in the frequency response but in some environments (in a car) it can be desirable to have a bit of a gap to compensate for the transfer function of the vehicle or to allow a bit more headroom for the high end speakers.
 
Thanks for the reply Perry.

In what ways does the environment and enclosure effect response? I assume this is why enclosures should be built within a certain spec size for certain speakers. But what happens to the response if the box is too big or too small? And what about the rest of the car?
 
Read through page 115 of the car audio site (link below). It shows how the enclosure affects the response of a speaker.

The vehicle/environment makes a huge difference in the frequency response, especially at very low frequencies. In general, car speakers are made to work in small enclosures and need to be relatively efficient. This means that they won't be able to produce very low frequencies (high f3). Lookup Hoffman's iron law for more details. When you install them in a vehicle, the transfer function of the vehicle allows you to get significant low frequency output from them.

A good example can be seen when working on a vehicle with long speaker wires. You can have four 12s (for example) that will produce so much bass that it makes it difficult to see straight in the vehicle. Take them out of the vehicle (as you might do of you need to get to the amplifiers) and they produce about as much bass as a good pair of 6x9 (installed as they would normally be in the vehicle).
 
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