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abdalrhman9 06-06-2019 01:30 AM

weird bass noise in high volume
 
Hello there

I have an issue occur in the rear speakers when bass hits in high volume !

The problem that my amplifier (4 Channel) doesn't have a HPF switch for the rear speakers it has for the front speakers only and i feel like the speakers struggle to produce the low frequency and thus it get distorted !

i have two questions about this :

1-is it ok to plug the 4 speakers in the front output in the amp ? 2x left and 2x right so that all speakers has HPF on ?

2- Since the speakers has a built in crossover why do we need high pass filter ?

OldNewbie 06-06-2019 06:08 AM

Re: weird bass noise in high volume
 
Quote:

Originally Posted by abdalrhman9 (Post 5709521)
Hello there

I have an issue occur in the rear speakers when bass hits in high volume !

The problem that my amplifier (4 Channel) doesn't have a HPF switch for the rear speakers it has for the front speakers only and i feel like the speakers struggle to produce the low frequency and thus it get distorted !

i have two questions about this :

1-is it ok to plug the 4 speakers in the front output in the amp ? 2x left and 2x right so that all speakers has HPF on ?

2- Since the speakers have a built in crossover why do we need high pass filter ?

1 - Maybe; it depends on the impedances of the two pairs of speakers and the ability of your amp to drive that load. If the speakers are 4 ohms each and your amp can drive the resulting 2-ohm load then you are OK. You will not be able to balance between the two pairs so I would look at alternatives. You could use some bass blockers on the rears.

2 - The speakers x-over only separates high frequencies from low, it does nothing to block low frequencies from the woofer. If there is a lot of low-frequency energy sent to a smaller woofer, the woofer can be overloaded which you seem to be experiencing.

Many here will discourage you from using rear speakers at all if you are trying to really achieve high SQ and solid imaging. It is hard to advise you without more information about the speakers, amp(s), etc. If you are running a sub, it would be possible to get a DSP, work around the front speakers x-over and go active with the front. You would then have a lot of control of what frequencies go where and their respective volumes.

abdalrhman9 06-06-2019 07:05 AM

Re: weird bass noise in high volume
 
Quote:

Originally Posted by OldNewbie (Post 5709559)
1 - Maybe; it depends on the impedances of the two pairs of speakers and the ability of your amp to drive that load. If the speakers are 4 ohms each and your amp can drive the resulting 2-ohm load then you are OK. You will not be able to balance between the two pairs so I would look at alternatives. You could use some bass blockers on the rears.

2 - The speakers x-over only separates high frequencies from low, it does nothing to block low frequencies from the woofer. If there is a lot of low-frequency energy sent to a smaller woofer, the woofer can be overloaded which you seem to be experiencing.

Many here will discourage you from using rear speakers at all if you are trying to really achieve high SQ and solid imaging. It is hard to advise you without more information about the speakers, amp(s), etc. If you are running a sub, it would be possible to get a DSP, work around the front speakers x-over and go active with the front. You would then have a lot of control of what frequencies go where and their respective volumes.



all my speakers are 4 ohms and this is my amp specification i linked it here i hope you can help me find if it's possible or not (KAC-M845)

http://manual.kenwood.com/files/B64-...00_English.pdf

and yes i'm running a subwoofer in the trunk but i'm not planning to buy a DSP tbh .

thanks

Truthunter 06-06-2019 07:35 AM

Re: weird bass noise in high volume
 
So you have a sub in the trunk and speakers in the rear deck?

abdalrhman9 06-06-2019 07:38 AM

Re: weird bass noise in high volume
 
Quote:

Originally Posted by Truthunter (Post 5709577)
So you have a sub in the trunk and speakers in the rear deck?

Yes , and i use factory radio and the old stock speakers were 4-ohms too

Truthunter 06-06-2019 07:50 AM

Re: weird bass noise in high volume
 
Could it be the pressure from the sub in the trunk pushing up the cones on your rear speakers and causing over-excursion?

abdalrhman9 06-06-2019 07:56 AM

Re: weird bass noise in high volume
 
Quote:

Originally Posted by Truthunter (Post 5709581)
Could it be the pressure from the sub in the trunk pushing up the cones on your rear speakers and causing over-excursion?

i don't think so , because when i lower the sub volume it still there

syc0path 06-06-2019 08:23 AM

Re: weird bass noise in high volume
 
Quote:

Originally Posted by Truthunter (Post 5709581)
Could it be the pressure from the sub in the trunk pushing up the cones on your rear speakers and causing over-excursion?

I've seen this issue as well. Simple way to check is to temporarily disconnect the rear speakers. If they're still making the same noise, then problem isn't w/ the signal.

Zardnok 06-06-2019 08:46 AM

Re: weird bass noise in high volume
 
Your amp is two ohm stable, so you can run all four speakers off the front outputs using the high pass crossover built into the amp. You will lose the ability to fade front to rear and it will skew the sound more to the rear than front.

My advice is to add some bass blockers to the rear speakers. These are capacitors that run inline with the positive speaker lead and provide a passive high-pass filter to your rear speakers. Depending on the size of your rear speakers, you should look for capacitors in the 250 microfarad to 133 microfarad which will give you a 6db high-pass in the 150 to 300 hz range on 4 ohm drivers. The bigger your speakers, the bigger the cap I would use, so if you have 6X9, I would look for 250 mic caps to cross around 150, if you have 6", I would look at 200 mic caps to cross around 200 HZ, 5" or smaller maybe look for some 133s to cut below 300 HZ. It is a 6db per octave slope, so it is a gradual roll off.

abdalrhman9 06-06-2019 09:04 AM

Re: weird bass noise in high volume
 
Quote:

Originally Posted by Zardnok (Post 5709605)
Your amp is two ohm stable, so you can run all four speakers off the front outputs using the high pass crossover built into the amp. You will lose the ability to fade front to rear and it will skew the sound more to the rear than front.

My advice is to add some bass blockers to the rear speakers. These are capacitors that run inline with the positive speaker lead and provide a passive high-pass filter to your rear speakers. Depending on the size of your rear speakers, you should look for capacitors in the 250 microfarad to 133 microfarad which will give you a 6db high-pass in the 150 to 300 hz range on 4 ohm drivers. The bigger your speakers, the bigger the cap I would use, so if you have 6X9, I would look for 250 mic caps to cross around 150, if you have 6", I would look at 200 mic caps to cross around 200 HZ, 5" or smaller maybe look for some 133s to cut below 300 HZ. It is a 6db per octave slope, so it is a gradual roll off.

Thanks mate that really helped i have 6.5" speakers and i will look for 200 probably

i looked into one of them online but it says that it block the freq between 0-600 hz where the HPF block 0-80 hz !!

Zardnok 06-06-2019 09:54 AM

Re: weird bass noise in high volume
 
This is a calculator to help determine what size you need and a couple links to some inexpensive 200 microfarad caps. You can spend much more on caps if you want, but I seriously doubt you would hear any difference in your application.

High Pass Filter Calculator

https://www.parts-express.com/200uf-...citor--027-366

https://www.amazon.com/BB-199-199-BA...dp/B01BCFK268/


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