Repairing 3 way speakers (Looking for some help)

Rusbelio · 2012-02-01 9:32 pm

Why did you put negative mid wire to positive woofer and tweeter wire?

What parameteres about coil? DC Resistance Max? 8ohm or no matter?

Thanks for the diagram

mdocod · 2012-02-02 2:10 am

Here's a diagram of what I was suggesting plus a couple extras that might be worth tinkering with...

jerome69 · 2012-02-02 5:38 am

Rusbelio said:
Why did you put negative mid wire to positive woofer and tweeter wire?

Physical laws. A capacitor makes phase difference +90° And inductor too -90°... The result is 180° difference, then to keep a good summation, you must invert the mid.

Rusbelio said:
What parameters about coil? DC Resistance Max? 8ohm or no matter?

DC resistance for the coil near or below 0.3 ohms
The crossovers are done for 8 ohms drivers and you have 8ohms drivers ? no ?

Rusbelio said:
Thanks for the diagram

You welcome !

Note : in the second schematic you can adjust the midrange level by R2. You can increase the value (3.3 to 4.7) if you have too much mid. The crossover frequencies are 1kHz and 4kHz The overall sensitivity of the speaker is 90dB. It was my first tweak of a speaker using measurements.

jerome69 · 2012-02-02 6:16 am

note 2: in your schematic, the first, to adjust the level of the mid put a simple resistor in series with L2 C2, R2 to 2.2 to 4.7 ohms.

Rusbelio · 2012-02-02 11:16 am

jerome69 said:
Physical laws. A capacitor makes phase difference +90° And inductor too -90°... The result is 180° difference, then to keep a good summation, you must invert the mid.

DC resistance for the coil near or below 0.3 ohms
The crossovers are done for 8 ohms drivers and you have 8ohms drivers ? no ?

You welcome !

Note : in the second schematic you can adjust the midrange level by R2. You can increase the value (3.3 to 4.7) if you have too much mid. The crossover frequencies are 1kHz and 4kHz The overall sensitivity of the speaker is 90dB. It was my first tweak of a speaker using measurements.

Its ok

Yes, 8 ohm all speakers.

mdocod said:
Here's a diagram of what I was suggesting plus a couple extras that might be worth tinkering with...

Thanks mdocod

But it's a bit difficult (according to the amount of components)

jerome69 said:
note 2: in your schematic, the first, to adjust the level of the mid put a simple resistor in series with L2 C2, R2 to 2.2 to 4.7 ohms.

Firs schematic in my first message of this thread?

Thanks

jerome69 · 2012-02-02 12:10 pm

Rusbelio said:
First schematic in my first message of this thread?

Yes

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

Uploaded with ImageShack.us

Rusbelio · 2012-02-03 2:08 pm

Its ok. Thanks

Another question, i have an amplifier with 4 to 8 ohm speaker conection (Right + left). If you calculate one 3 speaker system impedance in parallel, you get aproximately 2 ohm (according to the real impedance). Good for amplifier? Are you overcharging it? Right channel with 2 ohm and Left channel with 2 ohm too, according to measurements in parallel (1/8 + 1/8 + 1/8 = 2 ohm each speaker (All the box with 3 way system))

Its a simply amplifier (Kinter MA-180, very cheap amplifier and a very bad way to this speakers

)

I was looking some amplifiers like this

http://www.ebay.es/itm/290534649380?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

http://www.ebay.es/itm/SMSL-SA-50-5...ltDomain_0&hash=item19c9fc180c#ht_14253wt_962

Thanks.

Rusbelio · 2012-02-05 6:55 pm

Someone?

PeteMcK · 2012-02-05 9:53 pm

re:'you get aproximately 2 ohm ' - no, the crossover separates the impedance across its various freq bands, so it remains at (approx) 8 ohms

re:'you must invert the mid' - I disagree, here the components are for 1st order slopes at different crossover points, so no inversion.

Rusbelio · 2012-02-05 10:16 pm

PeteMcK said:
re:'you get aproximately 2 ohm ' - no, the crossover separates the impedance across its various freq bands, so it remains at (approx) 8 ohms

re:'you must invert the mid' - I disagree, here the components are for 1st order slopes at different crossover points, so no inversion.

Ok Pete. Thanks a lot

jerome69 · 2012-02-05 11:35 pm

PeteMcK said:
re:'you must invert the mid' - I disagree, here the components are for 1st order slopes at different crossover points, so no inversion.

Sorry you could be disagree but you are wrong...

Example
PRELUDE
Greencones

When we use 1st order filters we usually have to invert driver polarity and this is how it looks when
we connect bass and tweeter with positive polarity and mid with inverted polarity:

PeteMcK · 2012-02-06 1:18 am

Jerome,
Have another look at the ‘Prelude’ crossover. It is essentially a first order crossover on the mids, with quasi 2nd order on the woofer & tweeter. Normally one would invert the polarity of the woofer & tweeter; here, Troels has chosen to connect these in phase & invert the mid – same result.

Re: the ‘Greencones’, Troels himself says ‘Polarity of tweeter is dubious’

volume knob · 2012-02-06 2:11 am

If it's any help, I found some measurements for the tweeter

Projekt Forenbox-Billich-Willich - Seite 26 - DIY-HIFI-Forum (Half way down the page)

Its in German so you might need google translate

And for the midrange all I could find was this

Fs ......................300 Hz
Re.......................7.2 ohms
SPL......................97 db

www.loudspeakers.ca/Qmedia/Qcat66.pdf (2.8mb pdf page 15)

jerome69 · 2012-02-06 6:45 am

Pete no

we don't read the same things

Look at the graph of inversion of the polarity of the mid to positive on the prelude, sure it doesn't sound good

http://www.troelsgravesen.dk/PRELUDE_files/PRELUDE_T-invert_B.jpg

Rusbelio · 2012-02-06 2:19 pm

volume knob said:
If it's any help, I found some measurements for the tweeter

Projekt Forenbox-Billich-Willich - Seite 26 - DIY-HIFI-Forum (Half way down the page)

Its in German so you might need google translate

And for the midrange all I could find was this

Fs ......................300 Hz
Re.......................7.2 ohms
SPL......................97 db

www.loudspeakers.ca/Qmedia/Qcat66.pdf (2.8mb pdf page 15)

Thanks for the info

jerome69 said:
Pete no we don't read the same things
Look at the graph of inversion of the polarity of the mid to positive on the prelude, sure it doesn't sound good
http://www.troelsgravesen.dk/PRELUDE_files/PRELUDE_T-invert_B.jpg

Finally i invert mid truth?

jerome69 · 2012-02-06 4:18 pm

Rusbelio said:
Finally i invert mid truth?

I don't want to confuse you more, yes as i said you must invert the mid.
You are free to connect the mid with the same polarity ...

BTW what schematic will you do ?

Rusbelio · 2012-02-06 5:13 pm

jerome69 said:
I don't want to confuse you more, yes as i said you must invert the mid.
You are free to connect the mid with the same polarity ...

BTW what schematic will you do ?

This:

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

I have the components and its the best way for me

Cal Weldon · 2012-02-06 5:27 pm

Rusbelio,

Please do not hit the quote button on every post. That is there for when your post does not come right after the one you are quoting.

Thank you.

mdocod · 2012-02-07 6:27 am

According to my experimentation in a simulator, inverting the mid is correct for this application, when wired in phase, there is a significant null in response.

Rusbelio · 2012-02-20 6:25 pm

And now, i show the spakers:

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

3 sample videos

Prueba altavoz 3 vias reparado 1 - YouTube

Prueba altavoz 3 vias reparado 2 - YouTube

Prueba altavoz 3 vias reparado 3 - YouTube

They have a really good sound!

Thanks to the people who helped me

Repairing 3 way speakers (Looking for some help)

Member

Member

Attachments

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Member

Administrator

Member

Member