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Parallel vs. Series Speaker Connection http://dcaudiodiy.com/phpBB3/viewtopic.php?f=5&t=1286 |
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Author: | Cogito [ November 1st, 2018, 4:47 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
If the amp is marginally underpowered, it will drive the speakers without clipping when operated within limits, but the dynamics will be rounded off. A more efficient speakers ( ie: two 8 ohms in parallel vs a single 4 ohm) will only play the sounds little louder it will still have "lost" dynamics. |
Author: | Roscoe Primrose [ November 1st, 2018, 4:54 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
Assuming the 4ohm speaker has the same power sensitivity as the individual 8ohm drivers, the amp will have to produce only half as much power to generate the same acoustic output. The amp will have 3dB more headroom, how is that going to lose dynamics?!?! Roscoe |
Author: | SoundMods [ November 1st, 2018, 7:03 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
Actually, since the power sensitivity went up by 3dB, it ought to be EASIER for the amp to drive the 4ohm load created by two 8ohm speakers in parallel, assuming the OPT has a 4ohm tap. You're only looking at 20V across all three scenarios if you don't change output taps or use an amp (SS probably) with a vanishingly low output impedance. Remember, if you use the 16ohm tap to drive the series connection, and the 4ohm tap to drive the parallel connection, you're only getting half the voltage at the amp output for the same power delivered to the speakers. BTW, it would be a lot simpler to follow if you just used V^2/R for power Roscoe[/quote] To translate what Rosco said -- it's not rocket science and making a mathematical mountain out of a mole-hill gets confusing for no reason. |
Author: | Stuart Polansky [ November 1st, 2018, 7:55 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
Like any good internet thread, this one has gone way off of the rails and taken on a life of its own. Walter had the best answer, which was "gee,just try it and see". As to the power formula and Ohm's law, thanks for the tutorial, but I'm fairly familiar with them. As to comparing voltage input to the two variations, and as stated, in my case that means 8 ohms or 32 ohms, the notion of constant voltage input to either is wrong. If they were connected to an OTL or SS amp, sure, but (AS STATED) I'm connecting them to different taps of a transformer coupled amp: 4 or 6 ohms, respectively. This because the design I'm using actually requires OPTs with different turns ratios to achieve about 8K PP. I'll probably end up around 10k, so power will suffer a bit. If the gain is set to provide a set power level, the voltage applied to the 32 ohm speaker will be twice that applied to the 8 ohm speaker, since effective TR is doubled, right? So power level comparisons using a set voltage level don't work. Tom P told me in a phone conversation, that there was no acoustic power efficiency gain when series connecting speakers. (Unless I misunderstood him), I just accepted that as fact. He's a sharp guy, has messed with more speakers than Roscoe has bullets.Okay, maybe not that many. In either case, of course, the drivers are each delivering half the sound pressure, so distortion should be lower. All that crap said, again, I don't care about the efficiency. I am not using low powered or flea powered amps. I know that the speakers in question will BLAST Hell's Bells as loud as I can stand with a mere 16 watt amp. The new application will have more power than that. MY QUESTION is more about what happens sonically when two voice coils and all of their imperfections (parasitics?) are connected in series? In parallel, they are not interacting with each other as much, although, I suppose a non-global feedback amp with a substantial "non-zero" output impedance might allow the drivers to affect each other electrically. But in series, does anything, positive or negative in quality, happen sonically that would have one prefer a parallel connection? Anyone have any actual experience with a comparison between the two? The other half of that question was regarding the output transformers. Using the 16 Ohm tap halves the TR vs the 4 Ohm tap. I keep reading about the wonders of lower turns ratios and improved HF performance as a result. Perhaps that advantage is only seen with turns ratios which are a magnitude lower, not just half. When connecting to the 4 Ohm tap, the feedback connection isn't directly coupled to the speaker, it's typically left hanging off of the 16 ohm tap. Half of the output winding is generating an unterminated/unloaded signal. Seems like a less-than-ideal situation. I haven't experimented in this realm yet, was just looking for someone else's practical experience. Not a guide to the basic calculations, for goodness sake. But thank you. |
Author: | dberning [ November 1st, 2018, 8:36 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
Stuart, By all means, using the entire winding of the transformer provides better coupling and thus is more desirable in theory. Now on a comparison in listing, all bets are off. I don't see any fundamental problem with the two drivers in series. David |
Author: | Stuart Polansky [ November 1st, 2018, 8:48 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
dberning wrote: Stuart, By all means, using the entire winding of the transformer provides better coupling and thus is more desirable in theory. Now on a comparison in listing, all bets are off. I don't see any fundamental problem with the two drivers in series. David Thanks David! |
Author: | Cogito [ November 1st, 2018, 10:11 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
Roscoe Primrose wrote: Assuming the 4ohm speaker has the same power sensitivity as the individual 8ohm drivers, the amp will have to produce only half as much power to generate the same acoustic output. The amp will have 3dB more headroom, how is that going to lose dynamics?!?! Roscoe The point I was trying to make is, once the signal is screwed up due to AMP's inability to produce sufficient power on demand, having higher efficient speakers wont help. |
Author: | Cogito [ November 1st, 2018, 10:16 pm ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
Yes, the thread sidetracked a little from your original post. I was trying to clarify what was being said. Quote: Tom P told me in a phone conversation, that there was no acoustic power efficiency gain when series connecting speakers. Thats exactly what I said in post #3 in this thread. Quote: On the acoustic side, a pair of parallel speakers will result in +6dB gain and no gain in serial speakers.
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Author: | Stuart Polansky [ November 2nd, 2018, 8:54 am ] |
Post subject: | Re: Parallel vs. Series Speaker Connection |
Tom, Was waiting for you to reply on this. I remember you telling me there was an issue, but forgot the details. Thanks. My drivers have an FS of 37.7Hz. Plan is to use them over 100-125 Hz, depending...., so hopefully no issues. Stuart |
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