PDA

View Full Version : Finally going active, have a few ?



R05Nismo
04-30-2008, 09:25 AM
Ok, I'm running Boston Pro60's and picked up a Phoenix Gold ZX475ti along with a another set of RCA's. Will be using the crossover's in my Alpine 9887. Just for the heck of it I gave BA a call yesterday to ask a few questions about the set up and they made it sound like it was a bad idea?? Saying there are different types of crossovers used and there is much more to it than just the slope and crossover point etc... The only thing they told me if I still wanted to try it is don't cross the tweeter lower than 3K. He said it takes alot of time to design and build the crossovers used and I would be much better off just bridging the amp (250rms per side) and using the passive crossovers.

Is there really that much science behind this or what??

DejaWiz
04-30-2008, 10:50 AM
Yes, there is generally a lot of time spent and research done by reputable companies in designing a passive crossover for a set of components. However, if you know what you are doing and are armed with a few tidbits of knowledge such as the tweeter's Fs, then they'll be absolutely fine in an active crossover setup.

Sub: LP 63-80Hz, -18 to -24 dB/Oct.
Mids: HP 63-80 Hz, LP 2800-3000 Hz, -12 to -24 dB/Oct.
Tweeters: HP 3000 Hz, -12 to -24 dB/Oct.

Keep your amp gains down initially since the passive isn't there to dissipate some of that power...especially for the tweeters.

Play around with the crossover points and sloped so you can determine what sounds best for you in your vehicle.

R05Nismo
04-30-2008, 08:47 PM
Yes, there is generally a lot of time spent and research done by reputable companies in designing a passive crossover for a set of components. However, if you know what you are doing and are armed with a few tidbits of knowledge such as the tweeter's Fs, then they'll be absolutely fine in an active crossover setup.

Sub: LP 63-80Hz, -18 to -24 dB/Oct.
Mids: HP 63-80 Hz, LP 2800-3000 Hz, -12 to -24 dB/Oct.
Tweeters: HP 3000 Hz, -12 to -24 dB/Oct.

Keep your amp gains down initially since the passive isn't there to dissipate some of that power...especially for the tweeters.

Play around with the crossover points and sloped so you can determine what sounds best for you in your vehicle.


Ok thanks, nice reply. The tweeters should be ok because they are 8ohm so the power will be split in half.
One other thing I forgot to ask. The guy from Boston said about mounting the tweeter on the mid down in the door (they are in the dash now, stock location) and adding a set of Imaging tweeters in the dash that will play from 8k and up and a lower level. Any thoughts on that?

http://www.bostonacoustics.com/car/car_product.aspx?category_id=14&family_id=83&product_id=324

DejaWiz
04-30-2008, 10:02 PM
Eh, try it without the extra tweeters first when you go active. Because you get the ability to adjust cutoff frequencies and slopes, you may find a sweet spot with your current tweeters and won't need anything else in addition.

tcguy85
04-30-2008, 10:04 PM
how is your stage as is? do you find it to be low? if not, then don't bother with extra tweeters.

R05Nismo
04-30-2008, 11:10 PM
Well I moved the tweeters down by the mid just using some tape and the first thing I noticed was time correction was not needed. The tweeters are not as hard on my ears and the sound stage is much wider. It also didn't really seem to lower the sound stage too much either. I'm going to leave it like that for a day or 2 and see how I like it, then I might mount them on the mid. I won't have time to run the RCA's for active untill saturday.

tcguy85
04-30-2008, 11:43 PM
^^^ yup! tweets down low and far away FTW!!!

maldecido33
04-30-2008, 11:50 PM
Their is alot of R&D in designing passive crossovers. However, the goal of these companies is to make a speaker that can sound good in ALL types of setups, placements, etc.

Going active lets you tune a component system to your particular vehicle.

R05Nismo
04-30-2008, 11:55 PM
^^^ yup! tweets down low and far away FTW!!!

Instead of having them on the mid I was thinking maybe in the kick using angle mount? Or should they just be flush mounted?

tcguy85
04-30-2008, 11:57 PM
Instead of having them on the mid I was thinking maybe in the kick using angle mount? Or should they just be flush mounted?

thats where mine are (the kicks) i love them down there. i won't lie to you though... at lower volumes the highs do sound like they are coming from the kicks. but at moderate to high levels you can't place them. gives a very wide, and deep sound stage. and height is still very good at volume in my car.

try them in the kicks. see if you agree.

R05Nismo
05-01-2008, 12:02 AM
thats where mine are (the kicks) i love them down there. i won't lie to you though... at lower volumes the highs do sound like they are coming from the kicks. but at moderate to high levels you can't place them. gives a very wide, and deep sound stage. and height is still very good at volume in my car.

try them in the kicks. see if you agree.

Ok, thanks for your input. I'll have them running active this weekend.

R05Nismo
05-04-2008, 10:19 PM
Ok, did alittle work over the weekend. Ended up with the tweeters back up in the dash. That seemed to work best for me. The sound stage was a bit wider when they where lower but it was also more "in your face sounding" which I didn't care for.

Also, here is where I ended up with the crossover settings.
Sub LP 80Hz 12db slope
Mid HP 80Hz 12db slope / LP 2Khz 18db slope
Tweets HP 4Khz 18 db slope

Is having that gap from 2K on the mid to 4K on the tweeter ok? I couldn't seem to go any higher on the mid as it would get too harsh.

tcguy85
05-04-2008, 10:33 PM
Ok, did alittle work over the weekend. Ended up with the tweeters back up in the dash. That seemed to work best for me. The sound stage was a bit wider when they where lower but it was also more "in your face sounding" which I didn't care for.

Also, here is where I ended up with the crossover settings.
Sub LP 80Hz 12db slope
Mid HP 80Hz 12db slope / LP 2Khz 18db slope
Tweets HP 4Khz 18 db slope

Is having that gap from 2K on the mid to 4K on the tweeter ok? I couldn't seem to go any higher on the mid as it would get too harsh.

underlaps can work well in certain cases. just listen for obvious gaps. underlapping can be seen as an extra free EQ band.