Need help with crossover
07-17-2007, 01:40 AM
#1
Need help with crossover First off here is my system up front I have a pair of Boston Acoustics sl60 Components, and in the rear pair of Boston Acoustics sl65 Coaxials. For the low end JL Audio 10w3v3 in a JL audio Stealth Enclosure. For power I went old school and have a rockford fosgate punch 200 ix dsm and a punch 4080 dsm. Low end sounds excellent but the high end is getting way to much bass to the speakers. Unfortunatly the deck that Im using doesnt seem to have any good adjustments (JVC 2 years old). Now my question should I throw in a xover and what is a good one to use? Upgrade the head unit or maybe even use a pair of in line bass blockers. I would rather use a crossover so I can tweak in the right freq. but I cant seem to find a good one. I checked ebay and it seems like its either boss or lanzar. Any help or suggestions? Thanks
07-17-2007, 06:30 PM
#4
As far as I can tell the 4080 DSM has an internal crossover that can be adjusted just as most RF amps. What are the adjustment ***** right next to the RCA inputs?? There are 3 on one side and 3 on the other side. Couldn't tell by the pic I saw but there is definetely some kind of adjustment there. I know 2 are probably for gains but what are the others for?? Does one say HP/LP??
07-17-2007, 10:08 PM
#5
Welll....of course these amps are made back in 1994 so the only adjustments that they have are 2 gains and a bass and a trebel adjust. It does have a internal xover card but unfortunatly that doesnt leave much room for adjusting. Yes, the components did come with a passive crossover, but didnt really solve the problem. I know maybe I should of went for some of these new age amps with built in electronic xover's but what can I say I love old school power. Still up for suggestions on a xover...
07-18-2007, 08:54 PM
#7
I'd use a simple 2 way X-over like 95bat linked you to. All it seems you are looking to do is to put a 80-120hz High-pass crossover to the components. You can try some RCA low level bass-blockers, but you won't be able to tweak the X-over point. And they are usually a simple Cap or Coil passive X-over in a convenient package. So it's only 6-12 dB oct x-overs and they aren't really that cheap.
You also could go and add some simple (1st order) 6dB x-overs to the speakers by adding some caps. They must be the non-polarity type or it's discharge and cause a loud (and destructive over time) pop. Try starting in the 80-100hz range and you maybe surprised by how well it may work out and phase match with the subs. You can head to Radio Shack and get something that you want or head over to Best Buy, Circuit City or any stereo shop and they will have something you can use.
http://www.the12volt.com/caraudio/cross6db.asp
http://www.bcae1.com/xoorder.htm
500 µfd (MicroFarad) = 80 Hz (approx 4 ohm load) 400 µfd = 100 Hz (approx 4 ohm load) Just get close to the size. The Impedance will change with the frequency and the power amount into the speaker so it's not a super exact science for something fixed like this but it's very very close.
(FYI 500 µF (Micro) = 0.5 mF (milli) You usually don't see cF or dF sizes used much. http://en.wikipedia.org/wiki/Farad I.E. )
You also could go and add some simple (1st order) 6dB x-overs to the speakers by adding some caps. They must be the non-polarity type or it's discharge and cause a loud (and destructive over time) pop. Try starting in the 80-100hz range and you maybe surprised by how well it may work out and phase match with the subs. You can head to Radio Shack and get something that you want or head over to Best Buy, Circuit City or any stereo shop and they will have something you can use.
http://www.the12volt.com/caraudio/cross6db.asp
http://www.bcae1.com/xoorder.htm
500 µfd (MicroFarad) = 80 Hz (approx 4 ohm load) 400 µfd = 100 Hz (approx 4 ohm load) Just get close to the size. The Impedance will change with the frequency and the power amount into the speaker so it's not a super exact science for something fixed like this but it's very very close.
(FYI 500 µF (Micro) = 0.5 mF (milli) You usually don't see cF or dF sizes used much. http://en.wikipedia.org/wiki/Farad I.E. )
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07-20-2007, 12:01 AM
#8
wow...thats a very good website, very informative. Thank you for your help!! One more quick question. I was thinking about adding a eq to the system, possibly 5 band or 7 band. But I can find a really good deal on a used audio control eqt. My question is I heard that any thing under 7 band you can tune by ear but any thing above that you should use a real time analyzer. Is this true? Also I dont have access to a analyzer so should I waste my money on that eq or just pick up a 7 band 1/2 din unit. (which I have no idea wear to mount but thats a different story) Thanks for your help.
07-20-2007, 02:19 AM
#9
Actually, when you are very well experienced in SQ tuning, you do tune a 31 band by ear. BUT, this is something that I'm not really able to do well myself and I've been involved in car audio and electronics for 14 going 15 years now. It takes years and years of experience to teach your ears how to hear and how to learn what an instrument correctly sounds like and what effects are in which frequency range.
And you really don't do a final tune with an RTA. Usually you use one to adjust the curve (don't ever ever tune for a flat response) so it is smoother and has less sharp dips and peaks in the response. Usually most just tune with an RTA to get it close and fine tune it by ear.
If you can get the EQT's for a decent price, I'd get them BUT they are single channel units meaning that you'd need 1 for the Left channel and 1 for the Right channel.
ALSO Lets make it clear that an EQ is a set and forget item for the most part. You don't fiddle with it like tone controls. It's meant to help smooth out the response curve. You then use tone controls (Bass, Mid, Treble) to adjust the sound the way you'd like to hear it for each song. Unless you listen to 1 exact type of music all the time and don't mix it up too much. Keep the windows mostly up....etc. EQ's are not tone controls. They are specific frequency adjustment pieces.
And you really don't do a final tune with an RTA. Usually you use one to adjust the curve (don't ever ever tune for a flat response) so it is smoother and has less sharp dips and peaks in the response. Usually most just tune with an RTA to get it close and fine tune it by ear.
If you can get the EQT's for a decent price, I'd get them BUT they are single channel units meaning that you'd need 1 for the Left channel and 1 for the Right channel.
ALSO Lets make it clear that an EQ is a set and forget item for the most part. You don't fiddle with it like tone controls. It's meant to help smooth out the response curve. You then use tone controls (Bass, Mid, Treble) to adjust the sound the way you'd like to hear it for each song. Unless you listen to 1 exact type of music all the time and don't mix it up too much. Keep the windows mostly up....etc. EQ's are not tone controls. They are specific frequency adjustment pieces.
