Actually the app does not lower the impedance of the speaker. It just changes the amp somehow [1] to be able to safely feed a speaker with lower impedance.
[1] could be a lower power supply voltage, or limited output voltage, whatever ...
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What do I realistically need to drive a pair of 225w speakers?
- Thread starter andresdelnorteh
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[1] could be a lower power supply voltage, or limited output voltage, whatever ...
For me, "stupid loud" would begin about 85dB average with 105dB peaks. That would be with Audio Buddy and a few beers and some well chosen tunes.
As for power requirements, it goes up very quickly as you move into the "stupid loud" area,
If your speaker sensitivity is really 91dB at one watt, well, here's a crude estimate of power vs SPL
Normal listening might average 70dB with peaks of 90dB.
You'd need a handful of watts for that.
OP
andresdelnorteh
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I guess I'm just confused. The manual appears to say it has 8 ohm output but it seems people are saying that's wrong but I can't figure out why. And I think techies dont appreciate that most people just don't know about this stuff like at all so sometimes helpful answers are not super helpful because they're still over the head of people like me.Please don't take the following as another "utterly condescending and arrogant" input.
The first thing about speaker impedance value posted: This is an average measurement within/across the audio spectrum (20Hz-20kHz) that can swing wildly depending on the type of speaker/cross-overs/etc. << Take it with a grain of salt, please!
YOU can NOT lower the impedance as you state and adding resistance (parallel/series/quantum/wutever) is way out there in the galaxy but doesn't apply on Terra-firma!
Please take it easy and read members recommendations to you carefully. No one said it is wrong! We are trying to make you understand and absorb things most here take for granted and all you are doing is insulting and accusing. Please stop!
What the manual should say is that it it is safe to connect an 8 Ohm speaker without blowing the amp under normal circumstances. If you connect a 4 ohm speaker it will draw twice as much current for the same output voltage and hence twice the output power as well. It also increases the power dissipation inside the amp so it gets hotter. But even when you reduce the volume such that the 4 ohm speaker draws the same power as an 8 ohm speaker the former will still draw more current with increased power dissipation in the amp. Also the amplifiers power supply may not be able to deliver the current required to feed a 4 ohm speaker at high output power.
A properly designed amplifier protects itself against too much output current (accidental shortcut due to user, or playing too loud), too much power dissipation and too much heat.
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andresdelnorteh
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Don't worry, I'm out of here. I don't need any more assistance since it's totally lost on me anyway. It's specifically a thread for newbies but you'd never guess that from how people try answering questions. It's actually sort of maddening. I appreciate everyone tried but it's like people functioning at level 10 are speaking to me at level 3 or 4 and thinking it's helpful but meanwhile I'm on level 1. It's pointless for me to use this forum for help until I learn more so I can actually start to understand people.
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andresdelnorteh
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Thank you for this. I think I am beginning to understand.
The Onkyo manual is stating 8 Ohm speaker resistance and amplifier power output specs and is not stating what the 4 Ohm speaker specs are. Manufacturers usually do not state the 4 Ohm speaker amplifier power output spec because it looks bad on paper. It is due to lesser quality amp design and parts used that are not good at driving 4 Ohm speakers. You'll just need to trust us that it is 4 Ohm capable if you don't understand all the lingo, buzzwords and terminology.
Ohhhkaaayyy - to make it short: Since you said you listen not very loud and your speakers are quite efficient you don't need to worry at all about output power. A small amplifier with 20 to 30 W is more than sufficient (see @solderdude's posting), hence the Onkyo with 100W is certainly qualified and you don't need to worry about it being able to feed a 4, 6 or 8 Ohm speaker.
Apesbrain
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Your JBL speakers have been rated by the manufacturer to have a nominal 8 ohm resistance and to handle up to 225W without blowing up. The Onkyo receiver you are considering will deliver up to 100W per channel into an 8 ohm load. 100W into a speaker with a 91 dB efficiency will be very loud. There isn't much more to it than that.
If the Onkyo has the feature set you want, buy it.
Ohm's Law might be a good starting point for the electrical side of things.
Provided you have a handle on what Voltage, Resistance, and Current is about.
That's the most basic place to start, and goes a long way.
Frankly speaking, I am truly insulted by his posts.
It has been said that the average human "attention span" has been reduced by 4.25 seconds since year 2000. [it must be true.]
It has been said that the average human "attention span" has been reduced by 4.25 seconds since year 2000. [it must be true.]
It's not a negative value yet?
I think the regulars @ ASR are mostly composed of people that have fine tuned attention spans that exceed the average. We have to or we could not know what we know.
What I really meant to say was that the AttentionSpan# is 8.25seconds and I presume he was looking for such an answer befitting that #.
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andresdelnorteh
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It's not an attention span thing bruv, it's a terminology thing. I can stare at a tech term I don't understand for ten minutes, it doesn't mean I'll start to understand it or even know what I should be googling to start.
If you want to delve into some Ohms Law theory then I suggest the textbook, Principles of Electricity, Floyyd. Get the 8th edition(2007) or newer. The book/pdf is available online as a hardcover copy, softcover or a pdf. The new hardcover will cost into the hundreds of dollars, a softcover maybe $80 and a pdf can be viewed online or downloaded for free by subscription to a book club. Most book clubs offer the first 30 days free and can cancel the subscription anytime. You will only need to cover the first chapters as the remaining chapters are pretty intense and will be above your pay grade without a instructor to teach you.
EDIT: The text book can usually be found in university and college libraries too.
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JSmith
Master Contributor
They're reasonably sensitive at 91dB which means they shouldn't be too hard to drive and the power rating is basically the max the speaker can handle.
Keep in mind a doubling of power is only a +3dB SPL increase. Normal listening levels you probably won't crack 25W average... it's when you need to turn it up loud that more power is needed. If the amp starts to be driven into soft or hard clipping, distortion will rise sharply and then it shuts off.
So the Onkyo should be reasonably fine for purpose, but could run out of juice when volume is really pushed. If you need to do that on occasion, then get something with a bit more power output for peace of mind.
JSmith