Is filter degrading quality?

Aucosticraft · 25th April 2011, 06:35 AM

I have AVR137 HK make. It has its own filters for SUB out. When I plug amp without filter it sounds nice, but the moment I use LR filter 24 db Band pass filter the bass sounds unreal. The filter band is 11Hz-120Hz. ( why 120Hz is discussed in some other thread).

What do you suggest? I feel totally down and lost

Arty · 25th April 2011, 08:20 AM

please be a bit more specific.
Do You use an amplifier on the AVR137 SUB out ? what kindof amp?
or You have a 24 dBL band pass passive filter?
What driver are You using? what kindof box ?

Aucosticraft · 25th April 2011, 08:27 AM

On sub out of AVR137 I connect Active LR filter. the amp is ClassD. Its a vented sub enclosure. and when I say there is no filter then I just bypass the filter.

To describe more about sound is, It turns bit hard and feel like a bit small woofer.

Aucosticraft · 07:03 AM

Ok, I done one more experiment. I removed HPF of 11Hz and in other trial removed LPF of 120Hz. when I removed LPF, the above mentioned problem appeared. but when I removed HPF the quality was good again.

But with above results I am not sure what to conclude. if the HPF was not designed right? or the slope of this filter is doing something with the slope of filter implemented in AVR 137 ? or I made wrong choice of type of filter/ attenuation or frequency? or if i am using AVR 137 I don't need any filters as the filters are already implemented.

Pls guide me.

DrDyna · 02:44 PM

From the manual for your reciever:

Cso that SUB L/R+LFE appears in the
display.When this option is selected, a “complete”
feed will be sent to the front left/right
“main” speakers, and the subwoofer will receive
the front left and right bass frequencies under
the crossover frequency 80 Hz, additionally to
the LFE soundtrack (see above).

It seems the LFE connector on the back of the receiver is already crossed over, you probably don't need a second crossover.

Edit: If you want to use your own active crossover instead, connect it's input to the front L/R pre-out on the back of the receiver instead and assure that your main speakers are set to "large" in the receiver's config.

Arty · 26th April 2011, 08:19 PM

right. this is why must allso supply details in order to get a decent answer.

Aucosticraft · 27th April 2011, 05:52 PM

Thanks DrDyna. I still have doubt about HPF of 11Hz.

25th April 2011, 06:35 AM	#1
Aucosticraft diyAudio Member Join Date: Nov 2009 Location: Pune	Is filter degrading quality? I have AVR137 HK make. It has its own filters for SUB out. When I plug amp without filter it sounds nice, but the moment I use LR filter 24 db Band pass filter the bass sounds unreal. The filter band is 11Hz-120Hz. ( why 120Hz is discussed in some other thread). What do you suggest? I feel totally down and lost __________________ There is always a first time....

25th April 2011, 08:27 AM	#3
Aucosticraft diyAudio Member Join Date: Nov 2009 Location: Pune	On sub out of AVR137 I connect Active LR filter. the amp is ClassD. Its a vented sub enclosure. and when I say there is no filter then I just bypass the filter. To describe more about sound is, It turns bit hard and feel like a bit small woofer. __________________ There is always a first time....

26th April 2011, 06:34 AM	#4
Aucosticraft diyAudio Member Join Date: Nov 2009 Location: Pune	Ok, I done one more experiment. I removed HPF of 11Hz and in other trial removed LPF of 120Hz. when I removed LPF, the above mentioned problem appeared. but when I removed HPF the quality was good again. But with above results I am not sure what to conclude. if the HPF was not designed right? or the slope of this filter is doing something with the slope of filter implemented in AVR 137 ? or I made wrong choice of type of filter/ attenuation or frequency? or if i am using AVR 137 I don't need any filters as the filters are already implemented. Pls guide me. __________________ There is always a first time.... Last edited by Aucosticraft; 26th April 2011 at 07:03 AM.

26th April 2011, 02:41 PM	#5
DrDyna diyAudio Member Join Date: May 2007 Blog Entries: 3	From the manual for your reciever: Cso that SUB L/R+LFE appears in the display.When this option is selected, a “complete” feed will be sent to the front left/right “main” speakers, and the subwoofer will receive the front left and right bass frequencies under the crossover frequency 80 Hz, additionally to the LFE soundtrack (see above). It seems the LFE connector on the back of the receiver is already crossed over, you probably don't need a second crossover. Edit: If you want to use your own active crossover instead, connect it's input to the front L/R pre-out on the back of the receiver instead and assure that your main speakers are set to "large" in the receiver's config. Last edited by DrDyna; 26th April 2011 at 02:44 PM.

27th April 2011, 05:52 PM	#7
Aucosticraft diyAudio Member Join Date: Nov 2009 Location: Pune	Thanks DrDyna. I still have doubt about HPF of 11Hz. __________________ There is always a first time....


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25th April 2011, 08:20 AM	#2
Arty diyAudio Member Join Date: Feb 2011	please be a bit more specific. Do You use an amplifier on the AVR137 SUB out ? what kindof amp? or You have a 24 dBL band pass passive filter? What driver are You using? what kindof box ?

26th April 2011, 08:19 PM	#6
Arty diyAudio Member Join Date: Feb 2011	right. this is why must allso supply details in order to get a decent answer.

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