RC Low Pass Filter problem

[pranab]

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]

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]

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]

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]

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.

An externally hosted image should be here but it was not working when we last tested it.

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]

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]

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]

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

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

 

[Inductor]

DIY 101 - To Build an Inductor Coil

OK,
1. For a cored inductor you need less coil/turns.
2. For cored/air coil you use the appropriate gauge (look at the tables) for wattage. Ex: here you have
16 AWG (1.30mm) ~400/500w
Erse IXQ - Laminated Steel Core
14 AWG (1.63mm) ~750w
Erse XQ - Perfect Lay Air Core
Then with the gauge/diameter of the wire in mind, use the tables with as many turns as needed. More turns the more the inductance (gauge is for power only).

CNC Coil Winder (1) - From Left Over Parts - YouTube
#5 EPG Coil Winder, How It Works And Wrapping The Fist EPG Test Coil. Home Maid Troid Winder - YouTube
Mark 2 - Inductor Sim

 

[pranab]

OK,
1. For a cored inductor you need less coil/turns.
2. For cored/air coil you use the appropriate gauge (look at the tables) for wattage. Ex: here you have
16 AWG (1.30mm) ~400/500w
Erse IXQ - Laminated Steel Core
14 AWG (1.63mm) ~750w
Erse XQ - Perfect Lay Air Core
Then with the gauge/diameter of the wire in mind, use the tables with as many turns as needed. More turns the more the inductance (gauge is for power only).

CNC Coil Winder (1) - From Left Over Parts - YouTube
#5 EPG Coil Winder, How It Works And Wrapping The Fist EPG Test Coil. Home Maid Troid Winder - YouTube
Mark 2 - Inductor Sim

Thanks a lot bro ........ Now things are lot clear for me

 

[pranab]

driver suggestion needed

Guys I need some suggestion regarding a driver viz. almost similar to Eminence Alpha-8A 8" PA Driver 290-401
My frnd got a similar driver but for some reason he wants to get rid of it and he thinks he has wasted his money on this driver , its brand new and he would let go in very cheap price , (actually he bought it bcuz he was flown with the look of the driver). My wicked mind and knowledge (very little) says that its a great driver, i have even tested it with a left over enclosure ,it gives crystal clear sound, very responsive ......the only down side i found is the low end frequency isnt that gud , the Fs is at 73Htz and its a speaker with cloth surrounding with paper cone and 1.5" voice coil dia........
Guys plzzzz suggest me as to should I keep this driver (I can have it at almost half price frm my frnd). Its great driver but the only thing is that it lacks the low end frequencies . SOOO is there any way to design an enclosure so that it can sound gud at around 45Htz ????
I am attaching the pics of the driver and Bass Box Pro box design file for this driver .....Kindly give me some suggestion guys ..... Is there some way we can make this driver + enclosure sound lower .....???? (Sorry bout the bad quality camera of my phone) In real the driver luks gud .
P.S. - It also has the vent under the pole piece for heat dissipation of the voice coil.

 

[Inductor]

If the driver can sound close to Eminence Alpha-8A 8" it's not like having a woofer, there's nothing under 45Hz.

ALPHA-8A American Standard Series
Recommended for professional audio mid-range applications in a sealed cabinet, or as a mid-bass in a vented
satellite enclosure.

It may work nice as a mid driver (where are the TS parameters? can't read that file), or mid bass but my impression is who's doing a 45/50 L enclosure for a driver with f3=45Hz and no bottom end (like the Eminence Alpha-8A)???

 

[pranab]

If the driver can sound close to Eminence Alpha-8A 8" it's not like having a woofer, there's nothing under 45Hz.

It may work nice as a mid driver (where are the TS parameters? can't read that file), or mid bass but my impression is who's doing a 45/50 L enclosure for a driver with f3=45Hz and no bottom end (like the Eminence Alpha-8A)???

The file is Bass Box Pro 6.0.18 ....and the file is zipped right now, you can extract it or unzip it and run it in Bass Box Pro..
Am attaching spec of the Eminence Alpha-8A driver .
I know theres not much below 45Hz but i need an enclosure that accentuates the lower end as well because this driver lacks the lower end bass ......Due to space problem I want an enclosure design with Side firing driver and front port .....
Should I keep this driver bro ???
Is this a good deal ??
I know it dosnt sound like a woofer which has softer bass .... This driver gives punchy and hard hitting bass ...and yes even at high volumes it does not distort and it takes the beating very well ...I mean it produces the bass quite well and does not crack ...
What do i do bro ??
what enclosure should i use to accentuate the missing lower end bass ...(sealed or vented) ??

 

[Inductor]

I would keep it for a later project.

 

[Inductor]

Can't you resource the driver that I linked on post #20?
It's a nice driver?!
Iwai speakers - SUBWOOFER 8” 8Ω 75W
Contact

 

[pranab]

Can't you resource the driver that I linked on post #20?
It's a nice driver?!
Iwai speakers - SUBWOOFER 8” 8Ω 75W
Contact

Thanks a lot bro for ur opinion I am keeping the speaker with me, I have to pay only half the price .
I checked the iwai subwoofer and its great , I have also contacted them for the price and authorized dealer at my place (waiting for the response). Its actually kinda hard to find these products at my place , people are not aware of it .... But I am trying to found a gud subwoofer here ....

 

[pranab]

I would keep it for a later project.

Hi Bro ..I need ur opinion regarding the enclosure design for the above mentioned 8"PA driver.(attaching the enclosure design screen shot)
Is this enclosure design ok ??
The enclosure designed in a software is calculated in a particular ratio. So if i change the design a bit [lets say if i increase the height of the enclosure without changing other dimensions(it will increase the volume of the enclosure but it will also alter the ratio)] how much will it affect the sound quality OR what effect will it have on the overall audio performance.??
Wishing everyone Happy Holi

 

[pranab]

To Inductor,
The dimension of the enclosure is attached.
Kindly go through the Bass box pro screen shot in the earlier post. Is the enclosure design ok according to you ?????

The second design attached with this post is what I want to make but am not sure if it is going to sound good because the ratio of the dimensions have been altered my me.

Which enclosure design should I try to build.... the one which is designed in bass box pro OR the other one ???

plzzzz explain everything in detail bro ... I kinda noob here

Regards
Pranab