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home cinema gurus, your help is needed (regarding speaker impedance)

TheSVD

TheSVD

macrumors 6502a
Original poster
Sep 3, 2008
594
1
The Jolly Ol' Midlands, England
right, i've been scouring the web for a clear answer but i can't seem to find one...

Basically, i have an AV receiver which outputs 110w per channel at 6-16 ohms.
I have some older speakers i would like to use with it which are rated at 4-8 ohms.

Now, what i would like to know is whether i can safely use these speakers with my system, because i have heard mismatched speaker impedances can cause damage to the equipment.

However, i have heard that is only if you were to use 4 ohms on a 6-16ohm setup, but because the speakers do 4-8, surely they would work on 6-16 safely?

Ah i dunno, i really do have no idea, any help would be much appreciated :)
Cause i dont wanna fry my brand new surround sound :D
 
Best idea would be to go to Radio Shack and get some info from them likely they'll have some basic electronics manuals, possibly powered adapters/amplifiers capable of connecting whatever speakers you like to your system.

I wouldn't recommend connecting speakers directly to your system if the system is designed for one rating and the speakers are designed for another the difference can cause unwanted distortion in the sound quality potentially ruining your equipment attempting to drive power through the mismatched speakers. Whatever the wattage of the system is the speakers must match it to work correctly, same goes for ohms.

Last time I remember doing anything with an entertainment system the standards were 4 and 8 ohms some older systems had a switch so you could choose which suited you--occasionally I've found 2 ohms used in guitar amps too. 6 and 16 must be a newer standard I'm not too familiar with it. Does this amp use some sort of dial to adjust the ohms? is it on a switch where you can flip it from 6 to 16? Or does it just say that is its range so you can hook anything up that falls between those values?
 
ahh thanks man :)
yeahh 6-16 is fairly new i think, and no theres no switch, thats just the range of resistance it can withstand. i have been using the speakers with it for a new hours now and it seems fine, though i may switch them back cause i really dont want to break anything! i just heard because 4-8 technically falls between 6-16 (i dont know quite how it works) it might be okay. i always thought it was 6 TO 16 ohms, not 6 OR 16 ohms. beats me. anyone else got any ideas? :confused:
 
TheSVD said:
right, i've been scouring the web for a clear answer but i can't seem to find one...

Basically, i have an AV receiver which outputs 110w per channel at 6-16 ohms.
I have some older speakers i would like to use with it which are rated at 4-8 ohms.

Now, what i would like to know is whether i can safely use these speakers with my system, because i have heard mismatched speaker impedances can cause damage to the equipment.

However, i have heard that is only if you were to use 4 ohms on a 6-16ohm setup, but because the speakers do 4-8, surely they would work on 6-16 safely?

Ah i dunno, i really do have no idea, any help would be much appreciated :)
Cause i dont wanna fry my brand new surround sound :D
Click to expand...

Keep the volume under control and you will be ok, I have never had problems hooking 4 ohm speakers up to 8 ohm capable amps (but I rarely drive any amps past half). If you are planning on driving the amp hard, it may get upset, if it has an easy life, you won't have any problems. Basically, if your speakers have half the impedance, they can draw twice the power (so if your amp is up more than half way, you will likely be drawing more than the 110 watts it wants to give up)
.
Most modern amps shut down when they get upset instead of releasing the magic blue smoke anyway.

What is the purpose of these speakers? If they are rears in a surround system, you will likely never turn things up loud enough to cause problems.

As far as the range goes, on the speakers, they have different resisitance at different frequencies. On amps normally only the lower number really matters unless you start trying to connect many speakers (or are trying for efficiency).
 
ahh brilliant, thankyou :)
tbh im just going to reconnect the old ones anyway (which were bookshelf speakers) because they sounded just as good really. the purpose of them are to be used as fronts, and theyre the speakers i use to use for my hifi before i got this sound system. natrually, i thought i'd get the great sound from teh floorstanders along with extra bass.. however, when setup in 5.1, not much bass signal is sent to the front anyways so it didnt really sound alot different :)
Actually, just remembered... i have some 120w speakers rated at 6 ohms. would these be fine to use? i mean, theyre only 10w over...
thanks for the help though compadre :D
 
TheSVD said:
ahh brilliant, thankyou :)
tbh im just going to reconnect the old ones anyway (which were bookshelf speakers) because they sounded just as good really. the purpose of them are to be used as fronts, and theyre the speakers i use to use for my hifi before i got this sound system. natrually, i thought i'd get the great sound from teh floorstanders along with extra bass.. however, when setup in 5.1, not much bass signal is sent to the front anyways so it didnt really sound alot different :)
Actually, just remembered... i have some 120w speakers rated at 6 ohms. would these be fine to use? i mean, theyre only 10w over...
thanks for the help though compadre :D
Click to expand...

They will be fine. The rating on the speakers is just the maximum clean power they can handle. You could run speakers rated at 300W with a 10W amp (quietly) and it would be fine, impedance is all the amp sees.
 
it'll be fine
they are unlikely to drop below 6 ohms anyway

I currently run 2 4 ohm mangnepans biamped off of a receiver rated at 6 ohms with no problem and have been doing so for 4 years

for more bass from the floor standers make sure you have the receiver set up for front large so that it knows the proper cross over frequency
 
I wouldn't worry too much about it, as most people have said there shouldn't be a problem. The worst that could happen would be that the amp would be strained by the low impedance speakers and overheat, if used at too high a volume. Most modern amps will just go into 'protect' mode in this case.

I have a set of expensive new JBL speakers 8 ohm, 120w handling JBL speakers hooked into my amp and a couple pairs of tag sale/flea market 1980s mystery clunkers hooked into the other zones so I can have the same music throughout the house for parties. I just make sure to not run the amp at too high a volume with the other zones enabled.
 
I learned an interesting little trick or two that improved the sound quality immensely I suspended the smaller speaker boxes from hooks in the ceiling in fishing nets so nearly none of the wanted sound was being accidentally absorbed by any surrounding furniture it would have touched. Also the other trick with bass speakers to remove any overly hollow sounds requires filling those large speaker cabinets with sand (keeping in mind you have to protect the electronics inside them leaving a little airspace around the speaker itself) this method is more effective than stuffing bass cabinets with insulation.
 
cool, thanks for the replies guys :)
the system seems pretty solid so i guess ill just stick with the front tweeters for now.. i mean, i guess it was pretty bloody loud already, i just wanted more bass haha :D but with a 190w sub, it doesnt do bad..
thanks for the help though!
 
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