High pass filter question

[rdk]

Is the high pass filter the same IDEA in a 2x12 and horn PA cab as it is in a 2x15 and tweeter bass cab?

 

[billfitzmaurice]

If you mean that on the tweeter, which is half the crossover, the answer is yes.

 

[will33]

What are you looking to do? The PA cab would (should) have an LPF in it as well, if you're looking at moving some parts over.

 

[rdk]

We have an empty 2x15 PA cab. We bought 2 Delta Pro 15a to throw in it. Still need to put a horn in it. I was thinking of crossing over at about 15k. If I use these 8ohm drivers wired in parallel, do I still use a 4 ohm tweeter? And if so, would my cap be a 27UF?

 

[will33]

The HPF would be calculated for the tweeters impedanve at the crossover frequency regardless of the woofer impedance. I assume you mean 1.5khz, not 15. That calls for a quality mid/high horn and driver, a 3rd order filter, not a single cap, and a 2nd order LPF for the woofers.

 

[seamonkey]

Not much above 15khz that is usable.
Consider FM Stereo Radio, it has no audio content above 15khz
the Delta are going to cut off well before 15khz
A midrange horn with a real crossover and a tweeter with a real crossover would be best.

 

[rdk]

Oops. Yea meant 1.5

 

[rdk]

Ok. What instances would you just use a first order? I thought they were pretty common and often used in a 2 driver system such as a 2x15 and tweeter?

 

[billfitzmaurice]

We have an empty 2x15 PA cab. We bought 2 Delta Pro 15a to throw in it. Still need to put a horn in it. I was thinking of crossing over at about 15k. If I use these 8ohm drivers wired in parallel, do I still use a 4 ohm tweeter? And if so, would my cap be a 27UF?

At the very least you need to use a 3rd order highpass, and the woofers must be low passed as well.

What instances would you just use a first order

When you want to blow your horn midway through its first gig.

 

[rdk]

Thanks Bill and Will. Let me start over here. I have a million questions to ask since I am now confused considering I thought that my Madison 4x10 bass cab was a first order and I'm confused as to what the main difference is in that and the 2x15/horn PA.

Well, I'm just now learning crossovers. I have been using the formula

C=159,000/F x R

I assume F is the desired crossover frequency? Is that correct? Is this a good way to calculate?

 

[will33]

Some bass cabs do use 1st order, and it defines cheap. You basically can't get any cheaper. They set them up at 5-6khz. It makes them sound very harsh, causing players to turn them at least down if not off, thereby saving the tweeter, at least temporarily. Yet, there are still countless threads about blown tweeters, and Talkbass might be 2% of all the blown tweeters out there. IMO, if they do it that way, they shouldn't waste any time or money doing it at all.

Somebody with more experience than I would have to help with your calculations.

 

[billfitzmaurice]

I assume F is the desired crossover frequency? Is that correct? Is this a good way to calculate?

Passive Crossover Slopes

 

[rdk]

Some bass cabs do use 1st order, and it defines cheap. You basically can't get any cheaper. They set them up at 5-6khz. It makes them sound very harsh, causing players to turn them at least down if not off, thereby saving the tweeter, at least temporarily. Yet, there are still countless threads about blown tweeters, and Talkbass might be 2% of all the blown tweeters out there. IMO, if they do it that way, they shouldn't waste any time or money doing it at all.

Somebody with more experience than I would have to help with your calculations.

Will,
This makes sense.
A: the Madison 4x10 I have sucks
B: the tweeter is blown ha ha