Multiple drivers in same enclosure & resistors for attenuating tweeters

[bm_mode]

Hi all,
I'm quite a novice at the speaker building thing but have been reading as much as i can. I'm about to build some 2-ways with a dome tweeter and two identical woofers in a (vented) 3/2 D'Appolito configuration.I've selected the drivers and calculated cabinet size, port size etc using the standard equations (based on T/S parameters) for a single woofer. But if I'm using two (identical) woofers in the one cabinet enclosure, do I keep the the same cabinet/port dimensions? or double the enclosure size and ports?? or what??

I also have to attenuate the tweeter sensitivity. I've got the resistor values figure and was planning on using 1/4W 1% metal film resistors. Are these the right ones for the job or will I need some higher-wattage wire-wound resistors?

Thanks (in advance) for any advice you may be able to offer

Cheers

 

[Ignite]

Adding a second woofer throws off everything. You need effectively double the volume, thus a different port, etc. And you either get double or half the impedence of a single driver depending on wiring (half for series, double for paralell), so your crossover must be different.

As for the resistors, I don't know. 🙂

 

[baby_huey0]

I think you mean half for parallel and double for series.

huey

 

[tsz]

You'll probably need higher wattage resistors, somewhere around 5-10 watts is usually sufficient.

/Tobbe

 

[kelticwizard]

Just to add to what Ignite said, simply double the volume and calculate your port to tune the bigger box to the same frequency you were going to tune the single woofer enclosure to.