woodj
Super Member
I stand corrected.
Explain Like I'm 5: Speaker impedance/efficiency
- Thread starter Greg Nal
- Start date
Look at the specs on the amp in question. If it is rated for 8 ohms it will probably puke it's guts at a 2.7 ohm load. There are a few speakers that go down to 1 ohm and only a few amps that will survive driving them. Most amps see that 1 ohm impedance as a dead short. It will either go into protection mode if so equipped or will blow up and let the smoke out.
BillWojo
BillWojo
KingBubba
"Too Much Stuff"
I do it a different way. I plug in the speakers one pair at a time. The ones that get loud without turning it way up is efficient. If I try a different set of speakers and they get loud, but I have turn it up farther, then they are inefficient. It is just so simple to use your ears.
Is that pretty much true for all amps and receivers? I always thought that A and B would each see the load separately even when combined.
JoeESP9
ESL's & tubes since 83
Nope, it's always the total load because you only have two channels of amplification. While most amplifiers connect multiple speaker sets in parallel there are some that connect them in series. The Kenwood KM-106 is one that does. I suspect it's because of its limited ability to drive low impedance loads.
KingBubba
"Too Much Stuff"
My Kenwoods both do A + B in series and you will notice as soon as you fire it up, that you will have to turn the volume up farther to get the same sound level. This would also mean that your volume control will reach clipping at a lower volume level. I ended up killing a KLH woofer in this manner. It was clipped to death. For this reason I now always set up a second set of speakers with its own amp.
Thanks for posting that. I've had my 6's for some time and thought they were around 91db. No wonder even my 6 to7wpc SET amp pushes them to a decend level.Many older speaker companies did not publish sensitivity specs and it takes a bit more searching to find them. Usually an old stereo magazine test of that model will have those ratings. Also when one Googles the brand/model a lot of hits come up for this site with the info needed.
A good example of this is a page I found on eBay about some speakers I own, the Imperial 6. It was a dealer promo printed up by Marantz of a review in a magazine.
musichal
poet emeritus
Yep. If an amp will handle it, the owner usually knows because it's almost always big, heavy and didn't come cheap.
91.5 db 1w/1m
No problem! I found it about six months ago. My 2220B pushes my 6s to an earsplitting level in our small living room.
The test in the Marantz sales info sheet does not reflect that. After having mine for a while now and trying out several other speakers like my Small Advents, Sansui SP 70s, Polk RT25i, Nova 6s and 7s I tend to believe the higher figure.
Believe what you want, you are allowed, but I would appreciate you not clogging up the internet with misinformation.
Marine0811
I love it loud!
ROFL, get over yourself.
clogging up the internet with misinformation is second only to clogging it up with porn.
whoaru99
Epic Member
Gotta be careful in a number of ways with sensitivity specs.
Most, but not all are quoted at 1m. I don't recall the make and model but I saw some specs on old speakers listed at 10 feet.
And, dB/W/m sensitivity may or may not be the same as dB/2.83V/m sensitivity, which are the two common ways of presenting the spec.
If the speaker is 8 ohms then sensitivity by dB/2.83V/m would equal sensitivity by dB/W/m.
However, if the speaker impedance is more or less than 8 ohms then dB/2.83V/m produces less or more power into the speaker.
For example, if a 4 ohm speaker is rated 90dB/2.83V/m then it is not an apples to apples comparison to a speaker rated 90dB/W/m because 2.83V into 4 ohms is actually 2 watts. So, to make it equivalent, you'd have to subtract 3dB and end up at 87dB/W/m.
Most, but not all are quoted at 1m. I don't recall the make and model but I saw some specs on old speakers listed at 10 feet.
And, dB/W/m sensitivity may or may not be the same as dB/2.83V/m sensitivity, which are the two common ways of presenting the spec.
If the speaker is 8 ohms then sensitivity by dB/2.83V/m would equal sensitivity by dB/W/m.
However, if the speaker impedance is more or less than 8 ohms then dB/2.83V/m produces less or more power into the speaker.
For example, if a 4 ohm speaker is rated 90dB/2.83V/m then it is not an apples to apples comparison to a speaker rated 90dB/W/m because 2.83V into 4 ohms is actually 2 watts. So, to make it equivalent, you'd have to subtract 3dB and end up at 87dB/W/m.
KentTeffeteller
Gimpus Stereophilus!
Yes, only a select few separate power amplifiers will run that load without overheating, blowing fuses, or blowing transistors and other components. Even fewer receivers can handle this load.
exactly, I forgot that relationship. you know your shit
ev13wt
Super Member
More than half of total internet traffic is porn.
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