Very Simple Low and High Pass Pre-Amp Filters Help

houndazs · 9th May 2011, 03:39 PM

First i would like to say thank you for any reply in advance to this thread. I am a total n00b when it comes to anything audio, but i do have a little knowledge of electronics and am good at PCB repair. ok so what do i need....? I have a DIY project that i am 90% complete with and need 2 things a low and high pass filter. this is what i have so you have an idea for my needs.....

1ea 25w x 2 Channel Mini amp Sure 2x25W @ 4 Ohm TPA3123 Class-D Audio Amplifier Board

1ea 4" 8ohm woofer Dayton Audio DA115-8 4" Aluminum Cone Woofer

2pair el cheapo 10w 3" speaker Amazon.com: Newcom QS760 Passive Speaker Pair: Electronics

So my set up is as follows.....

Sub on channel 0 of amp
all 4 el cheapo speakers on channel 1 of amp
Input is coming from phone/mp3 player/ect....(anything with 3.5mm jack)

Now my problem is sound quality. I need to filter out the "lows" on the small el cheapo speakers, and filter out the "highs" on the 4" woofer. I need to be able to do this in the cheapest and easiest way possible. I have a total budget for electronics to include amp, and speakers of $50. so i have about $10 to spend on caps and resistors. all im looking for is a simple cap, and resistor in series circuit to go before the amp, i just don't have a clue what sizes i need or how to calculate the values of the components. if you guys could help me out i would be so so grateful. thank you!

houndazs · 9th May 2011, 07:51 PM

bump

houndazs · 11th May 2011, 12:32 AM

Quote:

Originally Posted by houndazs

First i would like to say thank you for any reply in advance to this thread. I am a total n00b when it comes to anything audio, but i do have a little knowledge of electronics and am good at PCB repair. ok so what do i need....? I have a DIY project that i am 90% complete with and need 2 things a low and high pass filter. this is what i have so you have an idea for my needs.....

1ea 25w x 2 Channel Mini amp Sure 2x25W @ 4 Ohm TPA3123 Class-D Audio Amplifier Board

1ea 4" 8ohm woofer Dayton Audio DA115-8 4" Aluminum Cone Woofer

2pair el cheapo 10w 3" speaker Amazon.com: Newcom QS760 Passive Speaker Pair: Electronics

So my set up is as follows.....

Sub on channel 0 of amp
all 4 el cheapo speakers on channel 1 of amp
Input is coming from phone/mp3 player/ect....(anything with 3.5mm jack)

Now my problem is sound quality. I need to filter out the "lows" on the small el cheapo speakers, and filter out the "highs" on the 4" woofer. I need to be able to do this in the cheapest and easiest way possible. I have a total budget for electronics to include amp, and speakers of $50. so i have about $10 to spend on caps and resistors. all im looking for is a simple cap, and resistor in series circuit to go before the amp, i just don't have a clue what sizes i need or how to calculate the values of the components. if you guys could help me out i would be so so grateful. thank you!

HELLO ANYONE.....PLEASE......?

houndazs · 11th May 2011, 02:02 PM

Well this is unfortunate........

gannaji · 11th May 2011, 03:52 PM

Dear Houndazs,
there are single and two transister filter circuits of JLLH on this site.

The Class-A Amplifier Site - Modular Pre-Amplifier Design

Hope this will be of help!

audiomodder · 10th July 2011, 07:44 PM

opamps will sound wayyyy better than a transistor preamp. and its easier to build. Try these:

http://www.physics.unlv.edu/~bill/PH...p_amp_filt.pdf

nigelwright7557 · 10th July 2011, 08:50 PM

Filter components for an RC filter would be 1/2 pi r c. This gives the breakpoint of the filter.

Personally I would have gone for a Sallen and Key or a Butterworth filter.

nelsonvandal · 11th July 2011, 05:46 PM

If I understand your intentions, you want to use one 4" speaker as subwoofer and four of the computer-like (but passive) speakers as satellites. If so, you'll need one stereo amp for the left/right speakers and another amp to drive the subwoofer. To control these amps you'll need filters as suggested above in some kind of preamp.

The alternative would be to buy one more woofer and use passive crossovers.

9th May 2011, 03:39 PM	#1
houndazs diyAudio Member Join Date: May 2011	Very Simple Low and High Pass Pre-Amp Filters Help First i would like to say thank you for any reply in advance to this thread. I am a total n00b when it comes to anything audio, but i do have a little knowledge of electronics and am good at PCB repair. ok so what do i need....? I have a DIY project that i am 90% complete with and need 2 things a low and high pass filter. this is what i have so you have an idea for my needs..... 1ea 25w x 2 Channel Mini amp Sure 2x25W @ 4 Ohm TPA3123 Class-D Audio Amplifier Board 1ea 4" 8ohm woofer Dayton Audio DA115-8 4" Aluminum Cone Woofer 2pair el cheapo 10w 3" speaker Amazon.com: Newcom QS760 Passive Speaker Pair: Electronics So my set up is as follows..... Sub on channel 0 of amp all 4 el cheapo speakers on channel 1 of amp Input is coming from phone/mp3 player/ect....(anything with 3.5mm jack) Now my problem is sound quality. I need to filter out the "lows" on the small el cheapo speakers, and filter out the "highs" on the 4" woofer. I need to be able to do this in the cheapest and easiest way possible. I have a total budget for electronics to include amp, and speakers of $50. so i have about $10 to spend on caps and resistors. all im looking for is a simple cap, and resistor in series circuit to go before the amp, i just don't have a clue what sizes i need or how to calculate the values of the components. if you guys could help me out i would be so so grateful. thank you!

10th July 2011, 08:50 PM	#7
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	Filter components for an RC filter would be 1/2 pi r c. This gives the breakpoint of the filter. Personally I would have gone for a Sallen and Key or a Butterworth filter. __________________ http://www.murtonpikesystems.co.uk PCBCAD50 pcb design software.

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9th May 2011, 07:51 PM	#2
houndazs diyAudio Member Join Date: May 2011	bump

11th May 2011, 02:02 PM	#4
houndazs diyAudio Member Join Date: May 2011	Well this is unfortunate........

11th May 2011, 03:52 PM	#5
gannaji diyAudio Member Join Date: Jan 2011 Location: Hyderabad	Dear Houndazs, there are single and two transister filter circuits of JLLH on this site. The Class-A Amplifier Site - Modular Pre-Amplifier Design Hope this will be of help!

10th July 2011, 07:44 PM	#6
audiomodder diyAudio Member Join Date: Jun 2009	opamps will sound wayyyy better than a transistor preamp. and its easier to build. Try these: http://www.physics.unlv.edu/~bill/PH...p_amp_filt.pdf

11th July 2011, 05:46 PM	#8
nelsonvandal diyAudio Member Join Date: Nov 2006	If I understand your intentions, you want to use one 4" speaker as subwoofer and four of the computer-like (but passive) speakers as satellites. If so, you'll need one stereo amp for the left/right speakers and another amp to drive the subwoofer. To control these amps you'll need filters as suggested above in some kind of preamp. The alternative would be to buy one more woofer and use passive crossovers.