full range driver opposing magnet in dipole configure

sagamotto · 16th April 2012, 04:30 AM

Hello DIY's friends...

Can someone here explain the effect(s) of say two 8" full range drivers put together in opposing magnet and wired in series of a dipole configure ?

how many drivers do i need to match my 100db bass onken ?
Its a 3 way design with the good old foster horn tweeter.

The 8" FR drivers I have on hand are those cheap and with the whizzer type.
Qts: 1.87, at 89 db.

VaNarn · 16th April 2012, 06:00 AM

I assume you have something akin to an Altec 515 in your Onken enclosure with passive crossovers. I am afraid that your idea of two cheap 8" drivers no matter how you baffle them or even use horn loading, will not work.You could try something from the Pro Audio area from Parts Express or other suppliers.

sagamotto · 16th April 2012, 07:08 AM

Well actually, the reason i asked the question to see if someone can tell me the effect of opposing magnet configuration on a high Q full range driver. This configuration is to be use for the mid range region of my 3 way design and by the way i forgot to mention that my bass driver is a 15" vintage Yamaha Ja-3881.
I only need to obtain a mid range near about 93-95 db to blend in between the the horn tweeter which i can further tune to match. As far as the low goes, you can't alway hear 100 db at all time. I mean bass only sounded when music signal allow in music. So, I don't see why the cheapo 8" full range can not work for my application...

Have anyone here already tried or currently experimenting dipole opposing magnet method?

VaNarn · 16th April 2012, 07:47 AM

The crossover frequencies in a passive network are important in as much as how power distribution and directivity are to be dealt with,that is,unless you are using a plate amplifier with the Yamaha 15'' so that it is in effect a sub-woofer.The only issue with back to back spacing is what it is going to do to the sound image and details of the actual dipole and distances from walls is not known.Perhaps the Audax PR 170 is a better solution for you to contemplate.

sagamotto · 16th April 2012, 08:09 AM

VaNarn... Thks for the quick replies...

BTW, its all passive 3 way design. The mid range I am planing to achieve is simply a dipole's series wiring. Infact its not even going to be in any enclosure either... Just two baffle pressing two FR drivers together (opposing magnet). I have not design the size of baffle yet... until I have gather enough infos.

Radugazon · 16th April 2012, 08:27 AM

Dipole opposing magnet ? That's a new term for me, but I think that I have been experimenting this with little baffle and variable spacing...absolutely no interest. IIRC, the same drivers in a classical layout work much better in radiation pattern or efficiency.
BTW, if you reverse the polarity of one driver, you gonna have a linear quadrupole. No match with your bass.

sagamotto · 16th April 2012, 12:23 PM

"but I think that I have been experimenting this with little baffle and variable spacing...absolutely no interest. IIRC, the same drivers in a classical layout work much better in radiation pattern or efficiency.
BTW, if you reverse the polarity of one driver, you gonna have a linear quadrupole. No match with your bass. "

Just a curiousity, but what drivers did you experiment with ? was it a FR high Q driver for mid range duty?

Radugazon · 16th April 2012, 01:28 PM

Was a PA 10", (TS parameters here), with phase plug and improved basket, done by the company that produces SB Acoustic .
Qts 0,37, Vas 38 liters, Fs 65 Hz, not a good OB woofer, but a mid range. With Le = 0,21 mH, not a FR too, but all these radiation pattern tricks never concern really the upper range.

sagamotto · 18th April 2012, 03:53 AM

My initial idea was simple, and seem to be in progressing, by combining the two drivers together (back to back or magnet to magnet) increases louder response (higher db gain) but also dipole advantage. Perhap it has alot to do with the FR driver magnet and energy storage pretty sure the parameter of the driver itself also changes. The sound I am hearing is clear and fast, very natural voice including string instruments, and uncolored. Even at higher volume play back (about 3 wts) both front and back cone vibrate very little, as well as my bass onken. If all this is happening from opossing magnet can someone here explain for me WHY?

here is the origin 8" FR spec:
Specifications: *Power handling: 30 watts RMS/60 watts max *VCdia: 1" Le: 0.68 mH *Impedance: 8 ohms *Re: 5.6 ohms *Frequency response: 100-16,000 Hz *Fs: 107 Hz *SPL: 89 dB1W/1m *Vas: 0.32 cu. ft. *Qms: 5.49 *Qes: 2.42 *Qts: 1.68 *Xmax: 2 mm.

Charcoal · 18th April 2012, 06:29 AM

I tried such push-pull dipole with identic FR drivers. Soundstage was much more precise than with normal dipole, when bothe sides of one driver are sounding.

In push pull dipole with two divers - they vere placed in the same minimal sealed volume, so only front sides were sounding to the room in dipole (not bipole) mode. We called it here "simmetrical dipole"

16th April 2012, 04:30 AM	#1
sagamotto diyAudio Member Join Date: Sep 2009	full range driver opposing magnet in dipole configure Hello DIY's friends... Can someone here explain the effect(s) of say two 8" full range drivers put together in opposing magnet and wired in series of a dipole configure ? how many drivers do i need to match my 100db bass onken ? Its a 3 way design with the good old foster horn tweeter. The 8" FR drivers I have on hand are those cheap and with the whizzer type. Qts: 1.87, at 89 db.

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16th April 2012, 06:00 AM	#2
VaNarn diyAudio Member Join Date: Dec 2010 Location: Ivanhoe	I assume you have something akin to an Altec 515 in your Onken enclosure with passive crossovers. I am afraid that your idea of two cheap 8" drivers no matter how you baffle them or even use horn loading, will not work.You could try something from the Pro Audio area from Parts Express or other suppliers.

16th April 2012, 07:08 AM	#3
sagamotto diyAudio Member Join Date: Sep 2009	Well actually, the reason i asked the question to see if someone can tell me the effect of opposing magnet configuration on a high Q full range driver. This configuration is to be use for the mid range region of my 3 way design and by the way i forgot to mention that my bass driver is a 15" vintage Yamaha Ja-3881. I only need to obtain a mid range near about 93-95 db to blend in between the the horn tweeter which i can further tune to match. As far as the low goes, you can't alway hear 100 db at all time. I mean bass only sounded when music signal allow in music. So, I don't see why the cheapo 8" full range can not work for my application... Have anyone here already tried or currently experimenting dipole opposing magnet method?

16th April 2012, 07:47 AM	#4
VaNarn diyAudio Member Join Date: Dec 2010 Location: Ivanhoe	The crossover frequencies in a passive network are important in as much as how power distribution and directivity are to be dealt with,that is,unless you are using a plate amplifier with the Yamaha 15'' so that it is in effect a sub-woofer.The only issue with back to back spacing is what it is going to do to the sound image and details of the actual dipole and distances from walls is not known.Perhaps the Audax PR 170 is a better solution for you to contemplate.

16th April 2012, 08:09 AM	#5
sagamotto diyAudio Member Join Date: Sep 2009	VaNarn... Thks for the quick replies... BTW, its all passive 3 way design. The mid range I am planing to achieve is simply a dipole's series wiring. Infact its not even going to be in any enclosure either... Just two baffle pressing two FR drivers together (opposing magnet). I have not design the size of baffle yet... until I have gather enough infos.

16th April 2012, 08:27 AM	#6
Radugazon diyAudio Member Join Date: Aug 2010 Location: Sulawesi	Dipole opposing magnet ? That's a new term for me, but I think that I have been experimenting this with little baffle and variable spacing...absolutely no interest. IIRC, the same drivers in a classical layout work much better in radiation pattern or efficiency. BTW, if you reverse the polarity of one driver, you gonna have a linear quadrupole. No match with your bass.

16th April 2012, 12:23 PM	#7
sagamotto diyAudio Member Join Date: Sep 2009	"but I think that I have been experimenting this with little baffle and variable spacing...absolutely no interest. IIRC, the same drivers in a classical layout work much better in radiation pattern or efficiency. BTW, if you reverse the polarity of one driver, you gonna have a linear quadrupole. No match with your bass. " Just a curiousity, but what drivers did you experiment with ? was it a FR high Q driver for mid range duty?

16th April 2012, 01:28 PM	#8
Radugazon diyAudio Member Join Date: Aug 2010 Location: Sulawesi	Was a PA 10", (TS parameters here), with phase plug and improved basket, done by the company that produces SB Acoustic . Qts 0,37, Vas 38 liters, Fs 65 Hz, not a good OB woofer, but a mid range. With Le = 0,21 mH, not a FR too, but all these radiation pattern tricks never concern really the upper range.

18th April 2012, 03:53 AM	#9
sagamotto diyAudio Member Join Date: Sep 2009	My initial idea was simple, and seem to be in progressing, by combining the two drivers together (back to back or magnet to magnet) increases louder response (higher db gain) but also dipole advantage. Perhap it has alot to do with the FR driver magnet and energy storage pretty sure the parameter of the driver itself also changes. The sound I am hearing is clear and fast, very natural voice including string instruments, and uncolored. Even at higher volume play back (about 3 wts) both front and back cone vibrate very little, as well as my bass onken. If all this is happening from opossing magnet can someone here explain for me WHY? here is the origin 8" FR spec: Specifications: Power handling: 30 watts RMS/60 watts max VCdia: 1" Le: 0.68 mH Impedance: 8 ohms Re: 5.6 ohms Frequency response: 100-16,000 Hz Fs: 107 Hz SPL: 89 dB1W/1m Vas: 0.32 cu. ft. Qms: 5.49 Qes: 2.42 Qts: 1.68 Xmax: 2 mm.

18th April 2012, 06:29 AM	#10
Charcoal diyAudio Member Join Date: Mar 2008 Location: Uzhgorod	I tried such push-pull dipole with identic FR drivers. Soundstage was much more precise than with normal dipole, when bothe sides of one driver are sounding. In push pull dipole with two divers - they vere placed in the same minimal sealed volume, so only front sides were sounding to the room in dipole (not bipole) mode. We called it here "simmetrical dipole"