diy 2.1 pc speaker

Thread Starter

juggler73

Joined Apr 10, 2010
47
so how does it all connect together

do those two circuit connect together for each channel
what happens to one side to the other its not like a speaker which side do i connect the woofer to right side or left or both and if thats the case how does that happen.

cheers
 

Audioguru

Joined Dec 20, 2007
11,251
if the tda2003 drove the small speakers then how can they be 4.3w when the tda2003 is a 10w amplifier?
Simply look at its datasheet.
The TDA2003 produces 10 Whats into 2 ohms with a horrible-sounding 10% clipping distortion when its supply is 14.4V. Its power is 7.5 Watts into 2 ohms at a fairly low distortion level. That is 3.75W for each of two 4 ohm speakers in parallel.

The active crossover circuit I showed has two lowpass filters for two woofers. Since you have only one woofer and only one amplifier for it then make only one filter but feed the lowpass filter from a buffer mixer circuit.

Retched is WRONG:
1) Do not use a bandpass filter for your tweeters. They need a highpass filter.
2) Do not connect a capacitor parallel to the woofer to make a lowpass filter. Instead an inductor is connected in series for a first-order filter, then additionally a capacitor can be parallel to the woofer for a second-order filter.
 

retched

Joined Dec 5, 2009
5,208
Retched is not WRONG. Audioguru just cant read. And makes stuff up so its more fun for him to put someone down.

I didn't say to put a cap in parallel. (even though I should have said inductor)
I didn't say to use a bandpass on a tweeter.

They ONLY came from you audioguru.
Retched is WRONG:
1) Do not use a bandpass filter for your tweeters. They need a highpass filter.
2) Do not connect a capacitor parallel to the woofer to make a lowpass filter. Instead an inductor is connected in series for a first-order filter, then additionally a capacitor can be parallel to the woofer for a second-order filter.
Now, when we are done playing audiogurus games, we can get this done.

juggler73, here is a page with some calulators for inductors and caps to be used IN SERIES for rolloff.
These are called passive crossovers. :
http://www.bcae1.com/passxovr.htm
 
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Audioguru

Joined Dec 20, 2007
11,251
[/COLOR]
can i use the l272m op amps i have?
It is a dual power opamp used for driving the tilt coils in a monitor and motors, not for audio because it has fairly high distortion and it does not produce high audio frequencies.
The TL072 dual opamp shown in the active filters I posted is made for audio with low noise, very low distortion and good performance up to 100kHz.

EDIT: corrected.
 
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Audioguru

Joined Dec 20, 2007
11,251
I didn't say to put a cap in parallel. (even though I should have said inductor)
Quoted from you: "With the filter caps, you can connect them across the terminals at thee speaker." That is a capacitor shorting the output of the amplifier at high frequencies, not a passive crossover filter.

I didn't say to use a bandpass on a tweeter.
You said "mid" but there are no mid-range speakers, there are a bunch of little 3" tweeters and one 6" woofer. A bandpass filter is not wanted.

Since the power amplifiers are separate then the crossover should be active, not passive.
 

Audioguru

Joined Dec 20, 2007
11,251
can you confirm the crossover chip TL072 or TL272 thanks
I have used hundreds of TL072 dual audio opamps and had tens of thousands of audio equalizers made with TL074 quad audio opamps. I have never heard of a TL272 and datasheetarchive.com also never heard of it.

The Linkwitz-Riley active crossover that I copied also uses TL072 audio opamps.
 

retched

Joined Dec 5, 2009
5,208
Actually my quote was:
With the filter caps, you can connect them as across the terminals at the speaker.
Which is where the confusion lies. I was apparently going too fast and was trying to say:
"Connect them as close to ; rather than "as across the"

And
When I sat this image:


I again, was moving to fast, and thought the image on the left was a tweeter, like the 1" variety I used to work with, and the speaker on the right was the midrange.

I wan under the assumption these "2" speaker made up the satellite speakers and the woofer the sub.

The OPs quote
im going to connect 2 speaker in parallel which think the speaker are 4ohms each.
ld me to believe they were talking about 2 speakers inside the satellite enclosure, the mid and tweet, then the woofer in the sub.

So I apologize. Your still a grump. ;)

[ed]

OK, The TLC272 is an OPAMP here is the datasheet:
http://focus.ti.com/lit/ds/symlink/tlc272a.pdf

And there is a reference to the TLE2072 from TIs page on the TL072
[/ed]
 
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Audioguru

Joined Dec 20, 2007
11,251
The 3" mid/tweeter looks cheap like it uses foam instead or real rubber for its surround.
A foam surround rots away in about 10 years but a real rubber surround lasts forever.
It looks like it is sealed then its lowest safe frequency might be a couple of kHz.

Lots of opamps have "72" in their part number.
 

Thread Starter

juggler73

Joined Apr 10, 2010
47
audioGuru@ im asking you which it was cause in the schematic its TL072

Then on a another post you said this "The TL272 dual opamp shown in the active filters I posted is made for audio with low noise, very low distortion and good performance up to 100kHz"

ok i get the fact they are 3" and there cheap but its all i have and it better than dumping them inside some landfill to rot for a hunderd years as i would rather recycle them
and there more 3" and 1/2 than 3"

A foam surround rots away in about 10 years but a real rubber surround lasts forever. who cares!!

thanks
 
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Audioguru

Joined Dec 20, 2007
11,251
I have used low noise, very low distortion and wide bandwidth TL072 dual audio opamps for about 30 years or more. Also Rod Elliot. Maybe on the other post I made a typo error.

I bought some Pioneer fairly cheap 8" woofers about 11 years ago. After 10 years their foam surrounds rotted away and now I must replace them.
I have a Philips woofer that is 45 years old. It has a real rubber surround (but it was not expensive) and it still works perfectly.
 

Audioguru

Joined Dec 20, 2007
11,251
those TL072 schematic do i use both or just one?
The TL072 dual opamps are labelled U1 A and B, U2 A and B, U3 A and B and U4 A and B. you need a 5th TL072 plus one TL071 single opamp.

I showed an active crossover that uses one opamp from a TL072 (U1A) as the input buffer for one channel (left). Its other opamp (pins 5,6 and 7) can be the input buffer for the other channel (right).
TL072 opamp U2A is the highpass filter for the left channel and opamp U2B is the lowpass filter for the left channel.
TL072 U4A is the inverting output buffer for the left channel highpass and U4B is the non-inverting output buffer for the lowpass for both channels mixed together.

You need a 5th TL072 for the highpass and lowpass filters for the right channel and you need a one TL071 single opamp for the inverting output buffer for the right channel highpass.
 

Thread Starter

juggler73

Joined Apr 10, 2010
47
that crossover circuit uses a split power supply but the tda7240 doesnt,
i found a circuit for tda2030 that does but ive had no luck with the tda7240

or maybe this doesnt matter
 
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