Multiple drivers in same enclosure & resistors for attenuating tweeters

bm_mode · 14th October 2001, 10:34 AM

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 · 14th October 2001, 10:40 AM

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 · 14th October 2001, 01:48 PM

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

huey

tsz · 14th October 2001, 02:48 PM

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

/Tobbe

kelticwizard · 14th October 2001, 03:21 PM

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.

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14th October 2001, 10:34 AM	#1
bm_mode diyAudio Member Join Date: Oct 2001 Location: New Zealand	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

14th October 2001, 10:40 AM	#2
Ignite diyAudio Member Join Date: Jul 2001 Location: Toronto, Ontario, Canada	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.

14th October 2001, 01:48 PM	#3
baby_huey0 diyAudio Member Join Date: May 2001 Location: Nova Scotia, Canada	I think you mean half for parallel and double for series. huey

14th October 2001, 02:48 PM	#4
tsz diyAudio Member Join Date: Aug 2001 Location: Göteborg, Sweden	You'll probably need higher wattage resistors, somewhere around 5-10 watts is usually sufficient. /Tobbe

14th October 2001, 03:21 PM	#5
kelticwizard diyAudio Member Join Date: Sep 2001 Location: Connecticut, The Nutmeg State	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.

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