The use of two 8 ohm drivers wired in parallel is very common but why don't we see more speakers with two or more 4 ohm drivers wired in series?
It seems to me that would produce a far more tube amp friendly speaker.
For example we could use two 7 0r 8 inch 4 ohm drivers which are around 92 db sensitivity [like some of the Scanspeak Discovery drivers] to give around 95db sensitivity and an 8 ohm impedance.
Drivers like this for example.
https://www.google.com/url?sa=t&sou...4QFnoECBQQAQ&usg=AOvVaw0D3Rizpjdd3KJ5iPTysgum
It seems to me that would produce a far more tube amp friendly speaker.
For example we could use two 7 0r 8 inch 4 ohm drivers which are around 92 db sensitivity [like some of the Scanspeak Discovery drivers] to give around 95db sensitivity and an 8 ohm impedance.
Drivers like this for example.
https://www.google.com/url?sa=t&sou...4QFnoECBQQAQ&usg=AOvVaw0D3Rizpjdd3KJ5iPTysgum
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They would stay at 92dB, unfortunately, due to the -6dB signal since it is divided between them.
You still get the gain in theory, which remains in terms of efficiency, just not in sensitivity. This way I agree that you could find application with an amp that prefers delivering voltage over current, if you take the meaning.
You still get the gain in theory, which remains in terms of efficiency, just not in sensitivity. This way I agree that you could find application with an amp that prefers delivering voltage over current, if you take the meaning.
Yes I should have said you get a 3db gain in efficiency by wiring two drivers in series.
I have owned some very good speakers that use two woofers wired in parallel [Dynaudio C5,Sonique Encore and Gale 401 ] but have always found them too amplifier fussy and therefore frustrating to own.I still love the Gale 401s but the optimal amp requirements for them are a bit silly.
I have owned some very good speakers that use two woofers wired in parallel [Dynaudio C5,Sonique Encore and Gale 401 ] but have always found them too amplifier fussy and therefore frustrating to own.I still love the Gale 401s but the optimal amp requirements for them are a bit silly.
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Curt Campbell's renowned TriTrix MTM and MTMTL designs use this configuration with the Dayton DC130BS-4; even in series they're almost as efficient as his 'Triune', which used DC130-8s in parallel. However, the Tritrix present an 8 ohm load to the amplifier.
I, like many people, built a pair of the vented Tritrix MTMs and they sound excellent for the modest cost.
Geoff
I, like many people, built a pair of the vented Tritrix MTMs and they sound excellent for the modest cost.
Geoff
The downside is inductance sums, so at least for wide BW apps need low inductance drivers unless of course they have a rising on axis response. 😒
i note the Ulluwata kit uses series/parallel with 6 woofers and looks to have a benign impedance and highish sensitivity.Anybody using them with a single ended tube amp?
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Many of the higher efficiency drivers do seem to have a rising on axis response.The Scanspealk one I linked does above about 1000hz.
It would be really interesting to see that response with two wired in series.It might mean getting away with a simpler and higher crossover which is a positive.
Le on that driver is only 0.33mH so double that is still only 0.66.
That is still pretty low.The Seas driver used in the A26 kits has an Le of 3.3 mH.
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Yeah, way back when 'we' DIYers took for granted that we had to find/make a complementary system for highest performance, SQ if we couldn't afford high SQ/power components, receivers with variable DF tone controls whereas nowadays can mix n' match with a cornucopia of components, systems to choose from and way cheaper to boot even before factoring in inflation, so when folks complain/lament about today's prices I'm not all that sympathetic.
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Not sure if this is relevant but for those of us with overgrown speakers, when you have them wired in series, if one happens to no longer value its own life, it stops the other from dying.
In parallel, they both jump off that bridge almost at the same time.
The guy who posted above me, you know him, he's from Chamblee Georgia, he will correct me where I'm wrong.
In parallel, they both jump off that bridge almost at the same time.
The guy who posted above me, you know him, he's from Chamblee Georgia, he will correct me where I'm wrong.
Hmm, is there something special about where I live I don't know about? 😵 Regardless, long time no hear, you still roofing or long since retired (no clue re your age) like me?
I've only diy'd since Covid but early-on did notice clear audible improvement with (good) vintage alnico wideband drivers, specifically 10" ovals Graetz 4ohm-4ohm or Goodmans 15ohm-15ohm in-series, over other wiring options or used singly. I didn't understand why and still don't.
(@jtgofish I pm'd you a month ago for advice re: RCF L15-554K 2-way, reflector-virtual-point-source see Fullrange photo gallery; a quad-deal fell through and that model has become much more expensive than other 15" PA/pro-drivers such as Fostex 15W300 which I got.)
(@jtgofish I pm'd you a month ago for advice re: RCF L15-554K 2-way, reflector-virtual-point-source see Fullrange photo gallery; a quad-deal fell through and that model has become much more expensive than other 15" PA/pro-drivers such as Fostex 15W300 which I got.)
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There is a problem with two drivers in the same box wired in series. There is an undesirable anti-phase coupling between the two cones. However, this may be no greater compromise than the many other sins committed in loudspeakers such as time misalignment and cross-over phase canceling.
Within reason yes.
And also other effective ways to make a more friendly impedance curve for transformer coupled or tube amplifiers.
Far as Wideband operation. Or at least in high power applications.
Tube amplifiers dont like no load conditions. So series connection if one driver is blown or damaged you have no load.
So often in high power live audio or musical instrument amplifiers. Series loads considered a no no for tube amps.
If you needed a work around for 4 or more speakers and impedance. Often you did see series loads.
But usually still 2 pairs parallel. Or otherwise usually series/ parallel is used. to reduce odds of no load situation.
Also depends on intent and off axis/ or crossover being used.
2x 8" 4ohm drivers series on crossover is still going to have dips or average relatively close to 4 ohms.
Far as vertical mounted drivers 2x 8" drivers closely mounted will behave close to 16" driver vertical.
So bandwidth is limited to around 800 Hz off axis.
For the most part, might as well use a 15" speaker. Which can vary from 95 to even 100 dB anyways
with high efficiency drivers. Assuming also possible Fs will be lower for 15" than equivalent 8"
So bass performance can theoretical be better. Also usually apple to apple comparison 4ohm coils
typically can have less sensitivity than equal 8 ohm coil. Depends but common.