JL 300/4 amp crossover?
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=72301
Printed Date: July 12, 2025 at 4:09 AM
Topic: JL 300/4 amp crossover?
Posted By: timmyjimmy5150
Subject: JL 300/4 amp crossover?
Date Posted: February 06, 2006 at 5:17 PM
I have a JL 300/4 amp..... It has front and rear croosovers on the amp....
Now.. in each of the 4 doors I have a set of Boston component speakers w/ tweeters..... When setting the crossovers on the amp.. I have 3 choices...
1.) HP -- high pass
2.)LP -- Low pass
3.) Off Which one do I want to set it at? Also.. My components came with their own set of crossovers that mount in the doors..... So, would I want the amp crossovers off since the bostons have crossovers already on them? Or do I set it at HP? I also have a 250/1 for a 10 inch sub under the seat... I believe it is set at LP... Thanks tim
Replies:
Posted By: sedate
Date Posted: February 06, 2006 at 5:38 PM
Set your 300/4 to: HP filter @ 100hz on BOTH channels.
Your 250/1 should be set to LP, also at 100hz.
The xovers that came with the Boston speakers seperate the frequency between the mid-range and the tweeter, they still need to be fed the proper input single, which is what the xovers on the 300/4 are for.
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"I'm finished!" - Daniel Plainview
Posted By: tcss
Date Posted: February 06, 2006 at 5:42 PM
What model woofer do you have? ------------- There is no such thing as free installation!
Posted By: timmyjimmy5150
Date Posted: February 06, 2006 at 6:06 PM
tcss..... When you say "what model woofer" do I have ---- You mean subwoofer...right? I have a JL 10w1 subwoofer......
Posted By: tcss
Date Posted: February 06, 2006 at 6:37 PM
Correct, is it an original W1 or is it a W1V2? The latter has a white cone.
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There is no such thing as free installation!
Posted By: timmyjimmy5150
Date Posted: February 06, 2006 at 7:17 PM
Posted By: timmyjimmy5150
Date Posted: February 06, 2006 at 7:21 PM
ALSO ---- What about :Filter Slope" on the JL 300/4 to my components? Do I want 12db or 24db? thanks
Posted By: timmyjimmy5150
Date Posted: February 06, 2006 at 9:01 PM
Any help on slope?
Posted By: tcss
Date Posted: February 07, 2006 at 6:10 PM
The filter slope basically is how many DB per octive the filter is rolling off the signal. I've heard two schools of thought on this. Some people believe a steeper slope is better (24db) because it eliminates unwanted frequencies at a more agressive rate. Others think a more gradual roll off can be useful also. I have the shop's demo car's slope set at 12db for the front JL ZR650csi speakers to leave a little more midbass for front staging.
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There is no such thing as free installation!
Posted By: stevdart
Date Posted: February 07, 2006 at 7:39 PM
The slope you choose will depend on your extended listening tests. Try the different settings and stick with the one that sounds the best. You'll be listening to the midwoofers as well, and one of those settings will give you the best crossover between the drivers. That's about all there is to it using variable active filters...listening and tweaking.
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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: sedate
Date Posted: February 08, 2006 at 1:33 AM
Generally, if your woofer is in a trunk, a higher slope will sound a bit cleaner... frequenty however, when the woofer is playing directly into the listening environment, a lower slope can actually blend with the midbass quite nicely, although I've found that this is almost exclusively with smaller woofers...
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"I'm finished!" - Daniel Plainview
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