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Old 18th May 2010, 12:51 AM   #11
ppia600 is offline ppia600  United States
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Location: Louis y ana
500 is too high if the high pass slope is about 12db like most outboard crossovers because if the speaker has low sensitivity in the frequencies below that (500 down to 65/70hz) you won't hear anything below 500hz and it will sound like the midbass is coming entirely from the rear i.e. you'll have a portion of the sound missing. You want the mids to play as low as they can efficiently do so the image comes from in front, not the trunk. A lot of people run a really high high pass for the mids and highs to prevent distortion but the distortion is usually caused by something else like bass boost on the deck that makes it through the crossover or lack of power for example.

When I put a system together I prefer:

Deck with good crossover, hp in front and rear about 70/80hz and low pass for the subs about 70/80hz
Amps with no crossovers or crossovers set to off/full range

or

Deck with crossovers set to off/full range and amplifiers with good crossovers set to the frequencies same as above

In both situations its good to use passive crossovers for the mids (if you're running components) to help keep some of the highs from the mids and make them more efficient at producing their intended range. Nowadays subs can run with no passive crossovers because at those power levels they are very inefficient and sap tons of power. A decent crossover in the deck or amp is sufficient for subs most of the time. I don't like using outboard crossovers as internal deck crossovers and internal amp crossovers have improved over the years and prevent noise issues (like yours) and also added distortion which no one likes.
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Last edited by ppia600; 18th May 2010 at 12:57 AM.
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Old 18th May 2010, 01:02 AM   #12
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Quote:
Originally Posted by ppia600 View Post
500 is too high if the high pass slope is about 12db like most outboard crossovers because if the speaker has low sensitivity in the frequencies below that (500 down to 65/70hz) you won't hear anything below 500hz and it will sound like the midbass is coming entirely from the rear i.e. you'll have a portion of the sound missing. You want the mids to play as low as they can efficiently do so the image comes from in front, not the trunk. A lot of people run a really high high pass for the mids and highs to prevent distortion but the distortion is usually caused by something else like bass boost on the deck that makes it through the crossover or lack of power for example.

When I put a system together I prefer:

Deck with good crossover, hp in front and rear about 70/80hz and low pass for the subs about 70/80hz
Amps with no crossovers or crossovers set to off/full range

or

Deck with crossovers set to off/full range and amplifiers with good crossovers set to the frequencies same as above

In both situations its good to use passive crossovers for the mids (if you're running components) to help keep some of the highs from the mids and make them more efficient at producing their intended range. Nowadays subs can run with no passive crossovers because at those power levels they are very inefficient and sap tons of power. A decent crossover in the deck or amp is sufficient for subs most of the time. I don't like using outboard crossovers as internal deck crossovers and internal amp crossovers have improved over the years and prevent noise issues (like yours) and also added distortion which no one likes.
WOW! Awsome response. As I have heard many times I guess I am going to have to bite the bullet and get a new deck. (I love my kenwood) My biggest problem is telling what the best frequency for the components are. I currently have my fronts set using only a 11uf for tweeter and the mid streight off the amp.. So electronic crossover is needed with this setup, and will have my rears very soon on a plannet audio amp separate from the fronts.. So guess I will be listing that kenwood radio and crossover together for sale and add the difference for a new stereo with builtin crossover to accomplish what I am looking for in this setup.. I beg to differ about passive as they have insertion loss as well as cause an impedence mismatch on the amp...

Also... my current crossover (stuck with it for now right) is connected to the front output rca on the radio.. Should I connect the monoblock to the rear rcas and just use its internal crossover? and use the crossover possibly to drive some woofers on the sub output to get a better fill IE: sub on HU, then woofer, front, and rear on the xover? till I do get a new headunit? The small alternator noise I can deal with till I sell it... also the slope is 18/db

Last edited by Simbalage21; 18th May 2010 at 01:09 AM.
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Old 18th May 2010, 01:19 AM   #13
ppia600 is offline ppia600  United States
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You don't want to use a 6db crossover on the mid or the tweeter... total suckage. The least should be a good 12db setup.

I wouldn't use an 18db slope on the mids and highs but it will work well for subs.

What model deck do you have? Is there any internal crossover at all or just full range? I would totally use the bass amp's crossover instead of the power acoustik's. What amps are running the highs again? Seems like they would have internal hp crossovers, probably better than the power acoustik either way... The kac 927 should have hp, is there any reason you're not using it?
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Last edited by ppia600; 18th May 2010 at 01:22 AM.
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Old 18th May 2010, 02:11 AM   #14
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Originally Posted by ppia600 View Post
You don't want to use a 6db crossover on the mid or the tweeter... total suckage. The least should be a good 12db setup.

I wouldn't use an 18db slope on the mids and highs but it will work well for subs.

What model deck do you have? Is there any internal crossover at all or just full range? I would totally use the bass amp's crossover instead of the power acoustik's. What amps are running the highs again? Seems like they would have internal hp crossovers, probably better than the power acoustik either way... The kac 927 should have hp, is there any reason you're not using it?
the kenwood headunit i have doesnt have no crossovers. I was however just looking at a sony xplode I have and it does however.. The reason I bought a electronic crossover is because I feel the one on the kac 927 is in efficiant, and ease of setting gains.. I currently have the kac927 running all four door speakers all the way around with plans to add another 2 channel to separate the front/rears thus why I purchased this crossover

update: hooked sony up.. it has LP and hP... both are preset @ off, 78hz, and 125hz and 3 RCA out.. isnt sony junk though?

Last edited by Simbalage21; 18th May 2010 at 02:16 AM.
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Old 18th May 2010, 05:42 AM   #15
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Default Well I installed The Sony

Although I am not a fan of sony I installed it.. I am thinking (havent went for a drive yet) That I may have skip problems. Also the unit has the 78/125 on the high pass and low pass. Why only these values? Will a newer unit have the same thing, or will it be variable like an external? And are these settings better then going passive? Currently I got it set to 125 and the amp set at full. Can you use a combination of Hp on the headunit and the amp or would the slopes interer. If getting a new headunit will give me what an external crossover will do then I am headed in that direction. In a post above someone mentions using a hp of 80.. must be some good speakers they got.. Also this radio has 3 rca.. assuming this is newer and my monoblock is newer. would I set the lp on the deck to 78 and turn the amp well higher then I would ever run the subs, OR turn the subs lp off on the headunit and use the one on the amp?

Last edited by Simbalage21; 18th May 2010 at 05:46 AM.
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Old 18th May 2010, 06:01 AM   #16
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Go to the Crutchfield site. They give the features and you can download the full owner's manual for most all head units. That should tell you about the crossover and other features.
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Old 18th May 2010, 06:15 AM   #17
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Originally Posted by Perry Babin View Post
Go to the Crutchfield site. They give the features and you can download the full owner's manual for most all head units. That should tell you about the crossover and other features.
Yea I did, Watched some videos, as well as read on alot of forums and get alot of "nobody really knows" and "it depends on your application".. I am just trying to figure all this out.. I know a properly tuned system will sound better (even if its cheaper) then an expensive poorly tuned system.. So thats all. trying to get the most of of what I got.. likewise. I see that if you go to high (like I had it) you miss parts of the audio spectrum as noted above.. but I did read you can cascade between the amp/headunit but nothing really tells..Even the product specs say there is a built in crossover, but nothing saying the frequencys or how that goes... I understand that its best to choose either the headunit or amp but how do you know which one is better/cleaner.. I just like the way an external works (the adjustability) and want to get that out of a headunit, or find one that wont turn out to make noise like the one I purchased did
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Old 18th May 2010, 07:12 AM   #18
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Unless you have an unlimited budget, being concerned about 78/125Hz crossover points is pointless. With average speakers, there will be so many other problems that using the 125Hz high pass and 78 on the low pass would not be a problem. You wouldn't miss anything. The frequency response of the average speaker in the average vehicle is absolutely horrendous. People generally want systems with a 3dB frequency response. If you get 10 in most vehicles without significant equalization (with average speakers), it's an absolute miracle. If you want an audiophile system that will produce significant SPL, you have to spend big bucks on high quality speakers that have a very nearly perfectly flat frequency response (separates, most likely), subs (the least important part of the system, a good 8" can produce good bass) and a head unit with DSP.

From previous statements, it sounded like you needed to set the high pass to 500Hz to get the highs to produce enough output. With better speakers and amps, you could set the crossover point lower. Unfortunately, most of us are on a bit of a budget and can't have the best of everything. To get the system to perform as well as you want with what you have, there are likely to be compromises. If you need the higher SPL on the highs, you may have to raise the crossover point. If you're willing to accept a lower maximum SPL, you could set the crossover point to where it needs to be to prevent having gaps in the frequency response.

Most head units produce virtually no distortion unless they're driven to clipping. The crossovers and the frequency where the tone controls/EQ boost/cut are very important but the speakers you have, the vehicle they're installed in and the mounting location will determine what's needed (eq and tone control frequencies).

Again, if you don't have an unlimited budget, you'll have to compromise. If you don't want to compromise, stop buying cheap equipment and wait until you can save up for good equipment (even if it takes a few years). I don't mean to sound harsh but it's the reality of building a good system.
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Old 18th May 2010, 08:13 AM   #19
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Quote:
Originally Posted by Perry Babin View Post
Unless you have an unlimited budget, being concerned about 78/125Hz crossover points is pointless. With average speakers, there will be so many other problems that using the 125Hz high pass and 78 on the low pass would not be a problem. You wouldn't miss anything. The frequency response of the average speaker in the average vehicle is absolutely horrendous. People generally want systems with a 3dB frequency response. If you get 10 in most vehicles without significant equalization (with average speakers), it's an absolute miracle. If you want an audiophile system that will produce significant SPL, you have to spend big bucks on high quality speakers that have a very nearly perfectly flat frequency response (separates, most likely), subs (the least important part of the system, a good 8" can produce good bass) and a head unit with DSP.

From previous statements, it sounded like you needed to set the high pass to 500Hz to get the highs to produce enough output. With better speakers and amps, you could set the crossover point lower. Unfortunately, most of us are on a bit of a budget and can't have the best of everything. To get the system to perform as well as you want with what you have, there are likely to be compromises. If you need the higher SPL on the highs, you may have to raise the crossover point. If you're willing to accept a lower maximum SPL, you could set the crossover point to where it needs to be to prevent having gaps in the frequency response.

Most head units produce virtually no distortion unless they're driven to clipping. The crossovers and the frequency where the tone controls/EQ boost/cut are very important but the speakers you have, the vehicle they're installed in and the mounting location will determine what's needed (eq and tone control frequencies).

Again, if you don't have an unlimited budget, you'll have to compromise. If you don't want to compromise, stop buying cheap equipment and wait until you can save up for good equipment (even if it takes a few years). I don't mean to sound harsh but it's the reality of building a good system.
Good point.. probably the best advise. because your correct we all wish we could have the best of the best but cant afford it. absolutly right that I had to set the crossover at a very high frequency to accomodate the hi power being sent to them. I guess what I was asking if I take and drive them to that kind of frequency, what can I do to make-up the lost bands? But from what your saying the only way to get dynamics upfront to be perfect is save up and just get good components that can take the power/frequency. So that probably would be the best thing to upgrade first? and what would be somethings to look for when buying door speakers? I have already learned u do get what you pay for.. so how do u know when your getting a bargan vs price? I was going to get a new headunit or better crossover first.. but I guess I will go speakers first.. But will that make the biggest impact on the vocals? or would I just wind up blowing them without the correct frequency first? My car audio is all I have left from things I used to be able to do. Networking/computers..used to build corporations, now I couldnt work an 8hr day if you paid me. So I take time and enjoy my car audio

Last edited by Simbalage21; 18th May 2010 at 08:18 AM.
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Old 18th May 2010, 08:24 AM   #20
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Default Components

One final question about components/Coaxials?

If I buy components.. would I have better results with

A. Using Passive that comes with them and setting amp and FULL pass
B. Having separate amps for mid/tweeter?
C. Buying Coaxials and running the amp streight to them with a freqency hp on amp or headunit?
D. Running HP on amp AND using passive crossovers

I dont do competition (YET) however I love the way people look when they see my little aspire bangin like it does.. Now I want them to hear my vocals blocks away too. power was my biggest issue, and its partially solved with dual battery isolator and optima yellow top on amps.. soon I will be needing a bigger alternator which is already 1 step higher then the stock one

Last edited by Simbalage21; 18th May 2010 at 08:30 AM.
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