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| Thread ID: 78241 | 2007-04-09 01:57:00 | Since were talking about audio... | pine-o-cleen (2955) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 539117 | 2007-04-09 01:57:00 | My car stereo has a problem . At medium to high levels of volume there is quite a lot of distortion, I think coming from the sony 6 x 9's in the rear . I think the problem is that they are trying to play the lower bass frequencies and this is distorting the mid - high frequencies . I have a separate sub connected through an amp with a low pass filter, filtering out anything above 80hz . I have often thought that a similar filter, doing the complete opposite (ie, filtering out the frequencies below 80 hz) would correct this problem . Am I right? Does such a thing exist? Now before you say 'you get what you pay for', all I'm trying to do is get the best out of what I have, without spending a lot more money . Reasonable don't you think? |
pine-o-cleen (2955) | ||
| 539118 | 2007-04-09 07:34:00 | What kind of amp is powering the 6x9s? If they are not getting enough power then they will distort at those volume levels. |
CYaBro (73) | ||
| 539119 | 2007-04-09 08:01:00 | It's called a crossover filter, every respectable multispeaker enclosure has them. Low frequencies go to the Bass speaker, the high frequencies are removed. Mid frequencies go to the mid range speaker, the high and low are removed. High frequencies go to the Tweeters, low and mid frequencies are removed. What is the wattage rating of the 6x9's? What is the wattage per channel of the Stereo? I disagree with the above that "not enough power" will cause distortion. Entirely the reverse. Either the speakers are being driven above thir rating or the Stereo is unable to provide the undistorted power without "flat topping" and distorting. |
godfather (25) | ||
| 539120 | 2007-04-09 08:38:00 | i think cyabro is meaning the amp is being run at max to get to that volume . when that happens you get a big jump in distortion, it kills tweaters quite quickly . simply turn the volume down . amps shouldn't be run above 3/4 volume . the other way around that is to filter out the bass either in the amp or before it (ie don't use a filter on the speaker) . as the bass takes most of the power to generate removing the bass will give the amp an easier life . the other thing is phasing, if the sub is out of phase to the 6x9 it can pump them ie sub tries to push the 6x9's out while the 6x9's are trying to go in . natually speakers out of phase don't produce good sound, having said that i've had it plenty of times and the owners have never noticed . |
tweak'e (69) | ||
| 539121 | 2007-04-09 10:23:00 | Should have explained more fully . The 6 x 9's are running straight off the head unit (Panasonic . . . . not sure of the model #, 4x 50w outputs) . I'm not sure what the speakers are rated at, but I'm sure its at least double that . The sub is the only thing running off the 222w Sony amp . . . . or the Stereo is unable to provide the undistorted power without "flat topping" and distorting . So, I should try running the speakers through the amp then? I've never used the amp for the speakers, I figured the head unit was putting out enough . |
pine-o-cleen (2955) | ||
| 539122 | 2007-04-09 10:54:00 | Could possibly be cheap or previously overdriven speakers, now suffering from cone break-up and consequent intermodulation between low and higher frequencies . However it actually sounds to me like you are trying to create a Mercedes by grafting a Honda Civic onto an aging Toyota ute . Each on its own is competent, if not exactly outstanding, but grafted together they are considerable less than the sum of their parts . That said, if you want your 6x9s to act as midrange speakers then yes, you would need to filter off the lows via a crossover network . Maybe you should back off the lows a little to give your 6x9's a chance . You may have a separate amp and low pass filter for the sub, but if the amp feeding the 6x9s is fed from the same preamp/equaliser then it will very likely be overdriving them . In my opinion they are probably just being swamped by the lows you are providing for your sub . Mobile music isn't supposed to lift your rear wheels off the ground or cause nosebleeds! Cheers Billy 8-{) |
Billy T (70) | ||
| 539123 | 2007-04-09 20:55:00 | Also, if your sub is boot-mounted and the 6x9's also use the boot as a "cavity" (i.e. they are OEM recessed into the rear parcel shelf) the large amount of LF pressure from the boot mounted sub will seriously affect the cones of the 6x9's. | godfather (25) | ||
| 539124 | 2007-04-09 22:38:00 | The sub is the only thing running off the 222w Sony amp. what input and ouputs does the amp have ? |
tweak'e (69) | ||
| 539125 | 2007-04-09 22:56:00 | The sub is the only thing running off the 222w Sony amp. That's not the point. The key issue is the sound mix going to the amp that feeds the 6x9s. If you have a single graphic equaliser and you have optimised it for the level of bass you want out of the sub (I assume you want to let everybody within a radius of 250 metres know you have this huge power level available) then the balance to your midrange speakers is going to be wrong and they will be over-driven at low frequencies. The midrange speakers also need to be isolated electrically, signal wise, and acoustically from the sub. "Electrically" includes the source impedance of the 12 volt supply too. At 200 or so watts, the sub amp will be taking 15-20 amp "bites" out of the supply and if it is on a common 12 volt source then the midrange amp could be suffering severe voltage sag on every bass beat. That will knurgle your sound quality something terrible through common-mode coupling. Of course you may already have all this sussed out and the right cabling etc installed, but it is worth mentioning just in case. Cheers Billy 8-{) |
Billy T (70) | ||
| 539126 | 2007-04-10 01:08:00 | . The midrange speakers also need to be isolated electrically, signal wise, and acoustically from the sub. "Electrically" includes the source impedance of the 12 volt supply too. At 200 or so watts, the sub amp will be taking 15-20 amp "bites" out of the supply and if it is on a common 12 volt source then the midrange amp could be suffering severe voltage sag on every bass beat. That will knurgle your sound quality something terrible through common-mode coupling. Of course you may already have all this sussed out and the right cabling etc installed, but it is worth mentioning just in case. Cheers Billy 8-{) you can't isolate the amps from a comman 12v source short of useing seperate sources. however you can beef up the power useing caps. they store power and, unlike batteries, release full power very quickly. this fills in the voltage dip which then allows the amp to run at full power :) |
tweak'e (69) | ||
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