Topic: Capacitor for super tweeter

[chaozhoi]

Hi, recently I added a pair of super tweeter to my mains. After adding, there is a noticeable improvement in the high range. Sometimes, certain parts of the music will sound too 'sharp' / 'high pitch' for my ear. I am using a 2.2 capacitor for the super tweeters. May I know if I should get another capacitor with bigger number or smaller to power down the high pitch a bit. Thanks.

[wwenze]

Assuming your tweeter is 8 ohm, 2.2uF gives ~9kHz crossover frequency.

Depending on situation you need either bigger or smaller value, what speakers are you using?

[synthesis]

You need a couple of resistors as well to tone down the output so it won't sound too strong.

[BTW]

Have a look at this website..

http://www.apicsllc.com/apics/Misc/filter2.html

Use the spks crossover calculator for the capacitor values...... and inductor values if you are using 2nd order crossover and above

For volume or level attenuation ... scroll downa bit more ..... use the L-Pad calculator..

[Vinylogy88]

                           Hi buddy, for me, I am using a "volume control knob type level attenuator" so I can adjust to the right ambience.                                                   It goes like this -Got the speakerbox from those cheap home theatre system for $5 @ pair from Sungei Road,Thief Market.(took out the original speakers)                                               Just use the box with the terminal originally fitted,soldered the inside with "Van dan Hul" thin speaker cables(specially for tweeters) then soldered to Caps which were soldered to Level attenuator also soldered to the Super tweeters with Silver solders.                                                                                                                                                                                  I did drill a hole on the wooden part of the small speaker that I mount the Volume-knob in.  Sprayed Speakerbox with a can of Black Flat spray paint and "waala !" New Speaker look!                                                                    The volume controller knob that I did was fitted on top of the speaker box which don't look fantastic but it gets the job done and I can easily access control for settings.                                  Got my API  Super Tweeters($75@) and Caps($5@) from Martin Electonics and level attenuator(forgot how much) from Sim Lim Tower.                                                                               CHEERS !

[chaozhoi]

Hi all, thanks for all the reply. Let me describe what happened until today since I got my super tweeter (ST).

All these while I have been connecting my super tweeter like the picture below. (I connected the ST raw, no box no enclosure or anything)


1) I started off with a 2.2µf capacitor only. I find the sound too sharp with a lot of 'sstt sstt' sound.
2) I assume I din get enough µf and I got a 3.3µf cap and results were more or less similar. Then I combined 2.2 and 3.3 and sound still quite sharp.
3) One day, I went to buy a 0.8µf and 1.2µf capacitor (i got a range of caps now) to experiment.
4) I find the sound of the ST very quite affected by the volume from my receiver. Soft sounds ok but once I turn up the volume, sound is very sharp with a lot of 'sstt sstt' sound no matter what µf I used.
5) I am using Belden 1307A cables for the ST and my mains are JBL studios S310ii 8ohms if you guys need to know.
6) I admit the vocals are much better now but the sharpness and 'sstt.. sstt..' sounds are quite irritating and I can't really volume up.

Some questions:
-Is the lower the µf the higher the pitch or the higher the µf the higher the pitch?
-Will adding resistors to the ST help? If yes around what value I should be looking at and how to connect them?
-Will using thinner tin cables help? The Belden 1307A is the thinnest cables I could get for pure copper as I think pure copper will produce warmer sound.

Some pics of how the ST looks like front and back:

[synthesis]

As mentioned in the link posted by BTW, below is the diagram.



Try to use 2.2uF only and add the above L-Pad resistors. Try R1 = 3 ohm and R2 = 10 ohm for a start, assuming the ST is about 5dB more sensitive than your speaker. Both resistors must be 5W or higher. R1 is in between the capacitor and tweeter.

[chaozhoi]

As mentioned in the link posted by BTW, below is the diagram.



Try to use 2.2uF only and add the above L-Pad resistors. Try R1 = 3 ohm and R2 = 10 ohm for a start, assuming the ST is about 5dB more sensitive than your speaker. Both resistors must be 5W or higher. R1 is in between the capacitor and tweeter.

ok I'll be dropping by Sim Lim tomorrow afternoon. So I guess I'll need to go get:
1) a L-Pad 3ohm 5W or higher resistor
2) a L-Pad 10ohm 5W or higher resistor

any other things I should get as well? Any recommended W for the resistor? I might not know what to get if being asked.

1 more thing, my ST did not state which point is + or which point is -. I just tried using an AA battery to test and see which point produces louder sound and assume that is +. The loudness was really very very close and I just picked one which I think was a very very very very little louder. There's no way I can check by seeing the movement of the tweeter btw..

[chaozhoi]

And the back of the ST states 8ohm and 500w in case you guys can't make out from the bur pics I took

[wwenze]

Capacitors in series: Effective capacitance = 1 / (1/a + 1/b + 1/c) i.e. the more physical capacitors you put in series, the less uF you get.

Capacitors in parallel: Effective capacitance = a + b + c

Less capacitance = more sharp

[ghemml]

Sharpness is related to the db level on the response graph, wheather there are any peaks or dips within the tweeter's response freq range.

Capacitors is to pass over(high-pass) at "F" freq given by the value of the capacitor and load(speaker)'s nominal impedence in the equation(6db/oct) C = 1 / ( 2 * pi * F * L)

C - Capacitance in farad
pi - 3.14
F - Crossover Freq desired
L - Load Nominal Impedence.

synthesis's method is a useful way to tone down the SPL level of the tweeter to almost the same level as your main drivers.

[chaozhoi]

my ST sounds better after added the resistors.. not so sharp and loud anymore.. but I still duno if it's the best it can do

[ghemml]

It depends greatly on how flat your tweeter can produce...

flat doesn't mean flat bass or brightness... its related to the response graph the tweeter can produce...

Simply picture your tweeter able to cover a range from 1000hz to 20khz. Throughout this freq range, the variation or changes in db doesn't increase or decrease much. e.g. at 2000hz at 103db, 3000hz at 105db, 4000hz at 102db... so on and so fore... This means you have a very flat response tweeter

Which there is no such thing as super perfect flat response... there will always be dips and peaks. Some have high peaks, and for this you will experience brightness over this region

[malsound]

my ST sounds better after added the resistors.. not so sharp and loud anymore.. but I still duno if it's the best it can do

If you are sure or happy that the current X-over network, next to help you tweeter blend better to your main speaker is to select the type or brand of caps. More often or not it is not the expensive paper & oil caps that blend well but the 50 cents or a dollar one at SLT.

[chaozhoi]

so I have to try out different brands to see if they will blend nicely? Will the difference be very noticeable?