Making a DIY 3 way

[greenhorn]

I have a Hertz Dieci DSK 130 component. the Matching 6x9's - DCX690 were damaged recently in an accident. I'm planning to add the mids used in the oval to the comps.

Current plan is to leave the comps as they are. Connect the mid via a first order HPF ( capacitor) at a cutoff of about 700 hz or more.
I assume the mid should be fine as it was connected directly to the input in the 6x9 where it was used earlier, but there is a capacitor , there, so i will confirm and get back.

Planning to go all passive. - all I have is an HU - the comps are not amped, and there are no fancy settings on the HU , and i cant afford anything exotic either. the need is to compensate for the loss of mids from the mid bass mounted in the door due to the reduced off axis response.

The other person is greenh0rn, who i believe is trying to tune his illusion comps

[navin]

Originally Posted by greenhorn

Current plan is to leave the comps as they are. Connect the mid via a first order HPF ( capacitor) at a cutoff of about 700 hz or more.
Planning to go all passive.

700Hz at 6db might be too much for the 2". Start slow.

Originally Posted by greenhorn

2. I couldn't find anything in between the wiring - though there is a cap,

I figured. I suspect the cap for the mid is like 6.8uf and the cap for the tweeter is about 1uf. Can you get the values of the caps on the tweeter and mid of the 690?

Originally Posted by Invinsible

What we need is each of the drivers parameters
There are many way can do this. You can add the mid to your componenet xover in place of the midbass and run mids and tweeter passive that way and run the midbass active. Or build a 3 way xover.

I dont think the driver parameters will be easy to get. if we get Fs atleast we can tell how low the driver can be pushed.

I see one problem...

if the mid is XOed at 1kHz and the tweeter is operating from 4K on given their relative position I see some comb effect creeeping in from 5K onwards maybe even earlier.

Still I say go ahead. Try it. Use the original dash grill for the mid. At best you can always bypass the mid and leave it inside the grill (non-operational).

[greenhorn]

700Hz at 6db might be too much for the 2". Start slow.

navin, its a 2.5"er actually. What do you think would be a good frequency to start - 1k?

[low_bass_makker]

Originally Posted by greenhorn

navin, its a 2.5"er actually. What do you think would be a good frequency to start - 1k?

1k is very high a bit lower will be good. Like 500 hz.

[greenhorn]

navin was saying that 700 itself might be too much. Thats why i thought of 1k. plus its going to be a passive first order crossover which has a very shallow (6db) slope

[navin]

Originally Posted by greenhorn

navin, its a 2.5"er actually. What do you think would be a good frequency to start - 1k?

Originally Posted by low_bass_makker

1k is very high a bit lower will be good. Like 500 hz.

Originally Posted by greenhorn

navin was saying that 700 itself might be too much. Thats why i thought of 1k. plus its going to be a passive first order crossover which has a very shallow (6db) slope

Ok I have seen 2.5" drivers with a Fs as high as 500Hz which means 1k/12db would be a good place to start with this driver. I assume the driver you have is better. A good indication would be either getting the Fs of teh driver or the cap that is in series with the driver.

Once we have the cap value we will know what the safe 6db XO point is. Then we can push the XO point an octave lower by going 12db instead of 6db. making a small 18/20 SWG inductor (about 1.5-2mH) using a soft iron or ferrite core wont be that difficult you might even be able to get one in the market.

Like I said before 2.5" drivers can go very low. Bose uses them as low as 150Hz. Ofcourse not all 2.5" drivers are equal. take these 2 made by the same company

FR070WA01_02
SW070WA01_02

[greenhorn]

Ok, I'm a bit confused. connecting a multimeter across the two leads from the assembly showed open circuit. connecting to one of the leads, and the point after the capacitor yielded 4.2 ohms.

the capacitor appears to be a 6.8μF non polarized one which translates to about 5.5khz cutoff which probably means that the cap is for the tweeter




here are some close up shots of the assembly.


So i thought that the midrange might have been damaged, and could have gone open circuit, but tried it as the center channel of my home stereo, worked fine - both the mid and tweeter.

I'm beginning to wonder if there is some sort of internal crossover within the driver

[navin]

Originally Posted by greenhorn

Ok, I'm a bit confused. connecting a multimeter across the two leads from the assembly showed open circuit. connecting to one of the leads, and the point after the capacitor yielded 4.2 ohms.

the capacitor appears to be a 6.8μF non polarized one which translates to about 5.5khz cutoff I'm beginning to wonder if there is some sort of internal crossover within the driver

If you accurately measure the impedance of the driver atleast one terminal must not be connected to anything.

Is there only one cap? If the tweeter is XOed at 5.5kHz/6db the mid should be XOed atleast 2 octaves lower so probably less than 1kHz/6db. I cannot see how the 2.5" driver can handle power below 150Hz so there has to be some XO somewhere.

[greenhorn]

navin, I'm just as stumped as you are. The pics show all the connections there are in the speaker.

Next stop, I'll try disconnecting the capacitor and see if the mid works. I'm beginning to wonder if the 'mid' is really a mid, or just a cone tweeter, in which case I'll have to shop around for something else.

I didnt hear much vocals out of it during the trials

[navin]

Greenie,

At first glance it looked like the $1.50 cone tweeters Bose used to use on their 301s.

If there is no other cap then try this...

disconnect the cap (hence also disconnecting the other tweeter) and only connect the cone tweeter/mid and see what emanates.

Unless the 6.8uf is being used by both tweeters in parallel.

[greenhorn]

Originally Posted by navin

Greenie,

At first glance it looked like the $1.50 cone tweeters Bose used to use on their 301s.

If there is no other cap then try this...

disconnect the cap (hence also disconnecting the other tweeter) and only connect the cone tweeter/mid and see what emanates.

Unless the 6.8uf is being used by both tweeters in parallel.

disconnected the capacitor, and both stopped working

seems the 'midrange' (as claimed by the spec) is also crossed over at 5.5Khz and is in parallel with the other tweeter. some midrange

let me see if i can get a separate driver

[DerAlte]

No, greenie, there must have been some error in measurement. In pic 2 and 3, one can see that the terminal to which the 2nd leg of the cap is soldered is not connected to anything other than the red wire going to the tweeter. It is just a terminal to ensure that the cap and lead to tweeter are soldered well and mechanically stable. Possibly, when you desoldered the 1st leg of the cap, the tinsel lead joint must have been disturbed, resulting in neither the mid nor the tweeter playing. You could try measuring the DC resistance from the 2nd leg of the cap to either tinsel lead - it should be OC.

The mid VC is fed directly through the tinsel leads on the right (pic 3). Try once again by disconnecting the tweeter red wire from the terminal (with the 2nd leg of the cap), without disconnecting the cap.

[greenhorn]

In pic 2 and 3, one can see that the terminal to which the 2nd leg of the cap is soldered is not connected to anything other than the red wire going to the tweeter. It is just a terminal to ensure that the cap and lead to tweeter are soldered well and mechanically stable.

nah, its connected to the base of the mid.

Possibly, when you desoldered the 1st leg of the cap, the tinsel lead joint must have been disturbed, resulting in neither the mid nor the tweeter playing. You could try measuring the DC resistance from the 2nd leg of the cap to either tinsel lead - it should be OC.

when i made the desoldered leg of the cap touch the terminal, both speakers turned on.

I think the first terminal is just there to have a landing place to connect the cap and the leads from the main terminal

The mid VC is fed directly through the tinsel leads on the right (pic 3). Try once again by disconnecting the tweeter red wire from the terminal (with the 2nd leg of the cap), without disconnecting the cap.

will do

[DerAlte]

Originally Posted by greenhorn

nah, its connected to the base of the mid. ...
I think the first terminal is just there to have a landing place ...

Strange. The 2nd terminal (on the right in pic 2, where the straight leg of the cap is connected) is isolated from the body of the mid by the orange-ish insulator.

Anyhow, we should see resistance between the white terminal (where the tinsel and black wire is soldered), and either the red terminal (tinsel) or orange terminal (straight leg of cap). Would be easier if you measure with nothing connected to these terminals.

[greenhorn]

Went hunting for a 4" mid. the only one i could find was a dainty 4" mid, and the damn thing would not fit in the dash location.

What now

try with the impostor midrange? lets see