RC Low Pass Filter problem

[pranab]

Originally Posted by picowallspeaker

At around 2:30 of that video ( nice music ) I hear...positive..negative...resistor...capacitor.. .source!
So it is clear that the filter operates at line level, as it should be for the
very low power (1/4 W) of the resistor, as also the value of the cap.
Source>preamplifier>LPF>amplifier>speaker

Mr picowallspeaker I LOVE YOU hehehehe I really luv u man......... Thanks a lot brother ..... I heard that video again with increased volume and figured the same thing .... positive..negative...resistor...capacitor ...... amp ..... Yes it is absolutely clear that filter shud operate at line level.
Thanks a ton brother

[picowallspeaker]

I wonder how it'll sound
As high-passing at line level is easier, not the same is for low-passing,
specially at those frequencies around 100 Hz . 'Mud' I think is the sound
produced by that filter arrangement, and if you're looking for something
better, the multimedia 2.1 ( 2 channels+ sub) systems often employ an
active lowpass, often preceded by a buffer to minimize losses ( in audible band)
given by the impedance matching of the various stages that act as filters themselves, for the same law of series and shunt resistors and associated capacities.

[pranab]

Originally Posted by gootee

Or change the circuit.

Pranab, what other speakers, if any, will be fed from the same amplifier's output?

If you allow only the bass to go to the sub, are you also wanting to allow only the mids and highs to go to some other speaker(s)?

How much output power are we talking about, in Watts? Do you have a multimeter or any other test equipment?

Hey bro
Now i feel a lil relaxed cuz the LPF prob have been solved .... OK i have 2 full range speakers at 4 Ohms and 1 sunwoofer at 4 Ohms ......So my plan is to put a sub with Lowpass filter and 1 speaker in series to play it at 8Ohms load with my player which is 1800Watts (written on the player itself) Dont know how much in RMS........ If it sounds ok then the second box will be made with another sub and 1 speaker and then both the box will be attached to the Left and Right channels of the Player ......... (thats the secret plan)
I havnt bought the secong Subwoofer, I have 1 Sub and 2 Fullrange speakers right now, If everything goes ok then only i'll purchase the other subwoofer.

[pranab]

Originally Posted by picowallspeaker

I wonder how it'll sound
As high-passing at line level is easier, not the same is for low-passing,
specially at those frequencies around 100 Hz . 'Mud' I think is the sound
produced by that filter arrangement.

OOPS........... i wrote dat wrong ..... the LPF filter circuit shud go before the AMP .....Thnks for correcting me.

[pranab]

Originally Posted by gootee

You could replace the resistor with a large coil (inductor). And the capacitor would need to be a large-ish electrolytic type, with a voltage rating that is higher than the peak output voltage of your amplifier.

Here is an example filter calculator:

Car Audio - 4th Order Butterworth Crossover Network Design Formulas & Calculator

You would use the low-pass filter, for the subwoofer. I don't know if you would need two stages, as shown, or not.

Here is an air-core inductor calculator (don't wind it on anything conductive or metallic):

Pronine Electronics Design - Multilayer Air Core Inductor Calculator

Either way, the larger the wire diameter is, the less resistance the coil will have, and the better it should perform. But I would not use larger than about 14-gauge, since it gets dificult to work with, and would be rough on your fingers.

Actually I wanted to avoid the Coil to make a LPF because its kinda hard to find it at electronic stores.. Resistor and Caps are easy to get and thats why i tried my luck in making RC Low pass filter ......
BUT anyways, now when everything is sorted out I think there is no option other than the Inductor coil ..... I'll definitely try to find one as soon as possible.
Thnks for the links bro...........

[pranab]

Originally Posted by WSJ

100 Hz Low Pass 4 Ohm Crossover


Convenient crossovers that work great in any application requiring economical and flexible filtering. Designed to be wired in-line between amp and speaker by using .205" disconnect terminals or soldering.

Specifications: • Approximately 250 watts RMS • Type: Low pass • Driver impedance: 4 ohm • Crossover frequency: 100 Hz • Roll off: 12 dB.


100 Hz Low Pass 4 Ohm Crossover 266-444

Thnks for the link bro.. I actually searched this on the net and found it on partexpress but I live in india and ordering some product from outside india adds extra cost to product like shipping and custom duty charges etc etc ......So the total cost of the product gets kinda expensive. It is a good product to have but it is not available at Indian websites ..(I wish i get this product in India)

[pranab]

Originally Posted by cT equals piD

pranab,

Most likely the integrated preamp/ power amp in your player is two channel, that is, stereo. It would be helpful if you told us if that is true or not. That presents the additional problem of mixing the left/ right channel signals in order to drive your sub-woofer with a L + R signal.

Have you looked at the rear panel of your player in detail? If your player is a very simple basic piece of equipment, it probably doesn't have any facilities for running a sub-woofer. But there is no harm done in looking. Do you have an owner's manual for the player?

-Pete

Yes its true it is two channel L+R .....It does not have a sub woofer out ....

i have 2 full range speakers at 4 Ohms and 1 subwoofer at 4 Ohms ......So my plan is to put a sub with Lowpass filter and 1 speaker in series to play it at 8Ohms load with my player which is 1800Watts (written on the player itself) Dont know how much in RMS........ If it sounds ok then the second box will be made with another sub and 1 speaker and then both the box will be attached to the Left and Right channels of the Player.

Pranab

[pranab]

Originally Posted by Inductor

I have some vintage subs at home (never needed) and they all have two woofers connected to the stereo in a bandpass type enclosure.
In this case what you need is a small inductor to connect in series with the woofer/sub.
Look at projects of 4th Order Bandpass Systems.
The Subwoofer DIY Page - 4th Order Bandpass Systems
,...
6 dB per Octave Crossover Table Values
SUBWOOFER 8” 8Ω 75W - iwaispeakers
Solid Core Inductors
Jantzen 1.0mH 15 AWG P-Core Inductor
ERSE 2.0mH 18 AWG I Core Inductor

First of all thanks for all the links provided. It have good information. And for the vintage subs you have kindly speedpost them for me hehehe

[Inductor]

Originally Posted by pranab

Mr picowallspeaker I LOVE YOU hehehehe I really luv u man......... Thanks a lot brother ..... I heard that video again with increased volume and figured the same thing .... positive..negative...resistor...capacitor ...... amp ..... Yes it is absolutely clear that filter shud operate at line level.
Thanks a ton brother

Originally Posted by Inductor

Are you sure you were in the correct website?

THANK YOU too, I also love picowallspeaker...

[pranab]

A lil help needed with the Inductor Coil thing ........
It will be a big help if somebody plz tel me how to make an inductor coil which is effective enough to be used as a low pass filter with least possible coil ..... It is hard to find inductor coil my place so plz tell me .....some points..
1. What effects the inductance ??
Thin wire with lots of turns is gud for a Low pass filter or a thick wire with less turns will be gud for low pass filter ???????
Also kindly mention what core should I use to make it most effective ....(shud be easily available aswell)
how how how ....???
Lots of questions in my mind lolzzzzz

Regards
Pranab