[taibanl]

Edit: COMPLETE!!!

Guys,

As you've seen I am running the Rainbow SL100 as my center, which I like because:

1. It matches my SLC210.25 set in my doors (at least in terms of construction)
2. Its relatively efficient (90dB/1w/1m@4ohms), the second most efficient speaker I've found in the 4" coax range.
3. It's almost bolt in (or it was with Musicar's pre-installed third mounting bolt clamp).

Unfortunately the SL100 has a 20w (min) - 30w (max) recommended RMS power range...which has limited my ability to run more power to it, to balance my front stage. Since I am planning a big power upgrade to my system...this had to be fixed....

Idea!

The Cal20 tweeter is allegedly the tweeter portion of this coaxial. Rainbow lists the cal20 as 100w tweeter! So what's holding back the power rating?!?! I suspect it is the limitation of having only a 6dB/octave crossover.

I had thought of biamping the center in the past to get more distortion free headroom for the same wattage...this is what got me thinking...If I am going to wire the mid and tweet separately, why not just delete the crossover internals?

[taibanl]

As you can see...the center of the coax includes the concealed crossover components. They are (in series):

• PTC Fuse (Sea-Land R60-065) (hold amperage of .65/trip amperage of 1.30)
• 4.7uF, 100v capacitor (4,229 hz Hi-Pass @ 8 ohms...more on this later)

I also tested the voice coils. The tweeter is 8ohm while the mid is 4 ohm...this was a surprise to me as the CAL20 tweeter when purchased as a component is a 4ohm tweeter...not sure if this affects my plans at all.

The question is...what should I replace them with? I plan on crossing the coaxial outboard of the speaker (either active w/ MS-8 or passive), but I want to retain some tweeter protection.

Choices:

• PTC only
• PTC + capacitor

The included PTC fuse was .65 amp. I bought a .75 amp, 1.1 amp and 1.3 amp PTC at parts express...I plan on using one of these..just not sure which. Since I am planning on a steeper cross than 12dB/octave I think its fine to go to a higher trip rating.

The capacitor options are either 10uF or 22uF as per the above link. 22uF gives me ~900hz Hi-pass, 10uF gives me ~2khz Hi-pass. (keep in mind I will run a dedicated crossover BEFORE the speaker....this is ONLY for protection...not for an effective crossover freq.)

What would you pick and why?

[taibanl]

Finally COMPLETE!

I ended up replacing the tweeter altogether with the 4 ohm version which I ordered from rainbow. I had to steal the mounting core off of the 8 ohm one, which was glued on pretty seriously.

I also purchased an extra crossover that matches my front L+R and is biampable.

Very excited to get this hooked up.

[cdgatti]

How do you balance the center with the front components? Meaning what spl level compared to the front mids? I was thinking about 3 dB less for the center?

[taibanl]

Originally Posted by cdgatti

How do you balance the center with the front components? Meaning what spl level compared to the front mids? I was thinking about 3 dB less for the center?

I am running ms-8 :

[cdgatti]

Yes I know you are, do you adjust your center after calibration?

[taibanl]

I used to dial it down. I dont any more. I Am sold on logic 7