Audio gurus - quick question!

[amnesiac]

I have 4 speakers which have 4 ohms impedance.

My receiver is a Pioneer VSX-D711 - not hifi by any means, and of course is rated to drive 8 ohms.

I understand that in many cases, powering 4 ohm speakers is a damn fine way to overheat your 8 ohm amp. However, a couple sites claimed that many 4 ohm speakers won't cause problems if they are very sensitive (>90db).

These speakers are 125db SPL @ 2m. Yes, they're that loud. Anyone know if I'll have trouble with these? Not that it matters, I have an extended warranty, I'd just like to know how safe it is.

 

[jurzdevil]

should be fine. i think thats how my brother has his running and thats been for a few years now.

 

[JoPh]

that probably wouldn't hurt anything

 

[Ameesh]

i would be careful about blowing out your speakers since the speakers are rated for less impedence but your reciever is expecting more, it will most likely pump out enough power assumin an impedence of 8 ohms.

 

[amnesiac]

Originally posted by: Ameesh
i would be careful about blowing out your speakers since the speakers are rated for less impedence but your reciever is expecting more, it will most likely pump out enough power assumin an impedence of 8 ohms.

I have never heard of anything like that. All the sources I've checked hinted at the overheating of the receiver, but like I said some countered that if you have sensitive speakers it wouldn't be a problem.

 

[rudeguy]

with home audio the ohms are very important...if you run those 4 ohm speakers into an amp that is only 8 ohms stable, the amp is going to basically work 2x as hard, it will not last long doing that

 

[sohcrates]

i wouldn't do it. i've seen home amps burn up when trying to power car audio (4 ohm ) speakers at high volumes.

what kind of speakers are these though? if you're powering little 6x9's or something, it might be ok. if you're trying to drive a sub or something though, it's gonna blow

 

[amnesiac]

Originally posted by: sohcrates
i wouldn't do it. i've seen home amps burn up when trying to power car audio (4 ohm ) speakers at high volumes.

what kind of speakers are these though? if you're powering little 6x9's or something, it might be ok. if you're trying to drive a sub or something though, it's gonna blow

They're Rogers DB-101 studio monitors. Bookshelf speakers. 1" tweeter and 5" woofer. Like I said, highly efficient at 125db.

I think I'll stress test the amp this weekend by blaring all 4 of the speakers for a few hours. If it blows, back to CC it goes.

 

[nguyendot1]

Originally posted by: sohcrates
i wouldn't do it. i've seen home amps burn up when trying to power car audio (4 ohm ) speakers at high volumes.

what kind of speakers are these though? if you're powering little 6x9's or something, it might be ok. if you're trying to drive a sub or something though, it's gonna blow

He's talking about a dolby digital home theater receiver. It wont hurt the amp as long as you don't crank the volume up.

 

[Shockwave]

Originally posted by: Ameesh
i would be careful about blowing out your speakers since the speakers are rated for less impedence but your reciever is expecting more, it will most likely pump out enough power assumin an impedence of 8 ohms.

What in the hell are you talking about?!

Anyways, the amp will be wokring half as hard (less resistance) so will be doubling power (theoretically). I would say worst case scenrio is an overheat. Granted, you could burn up components though. Does the amp have protection modes? I dont know if home amps have protection or not...

Anyways, at low to medium volumes you should be fine with no worries. Its when you start pushin the amp that it'll become a problem and risk ruining it.

One way to find out...

 

[nguyendot1]

Originally posted by: Shockwave

Originally posted by: Ameesh
i would be careful about blowing out your speakers since the speakers are rated for less impedence but your reciever is expecting more, it will most likely pump out enough power assumin an impedence of 8 ohms.

What in the hell are you talking about?!

Anyways, the amp will be wokring half as hard (less resistance) so will be doubling power (theoretically). I would say worst case scenrio is an overheat. Granted, you could burn up components though. Does the amp have protection modes? I dont know if home amps have protection or not...

Anyways, at low to medium volumes you should be fine with no worries. Its when you start pushin the amp that it'll become a problem and risk ruining it.

One way to find out...

The sound quality will drop too. Less ohms means less dampening, meaning less tight 'clean' sound.

 

[Shockwave]

Originally posted by: nguyendot1

Originally posted by: Shockwave

Originally posted by: Ameesh
i would be careful about blowing out your speakers since the speakers are rated for less impedence but your reciever is expecting more, it will most likely pump out enough power assumin an impedence of 8 ohms.

What in the hell are you talking about?!

Anyways, the amp will be wokring half as hard (less resistance) so will be doubling power (theoretically). I would say worst case scenrio is an overheat. Granted, you could burn up components though. Does the amp have protection modes? I dont know if home amps have protection or not...

Anyways, at low to medium volumes you should be fine with no worries. Its when you start pushin the amp that it'll become a problem and risk ruining it.

One way to find out...

The sound quality will drop too. Less ohms means less dampening, meaning less tight 'clean' sound.

That difference should not be discernable.

 

[Conky]

Shouldn't be a problem at all unless you listen to all your music at concert volume and even then it will take months to damage your equipment.

Enjoy your stuff.

 

[Twerpzilla]

Hi amnesiac, just to clarify things a bit for you, these speakers are rated at 92db 1w/1m. While this is slightly more efficent than your average speaker, your amp will still need to kick out some juice to drive these babys. While you may get away with running them for awhile, most likeley they will end up trashing your amp. Your best may be to find a reasonably priced tube amp off E-Bay. Such a amp will probably be wired for 4 ohm, and if not, wont burn up if you run your speakers at 8 ohms. And will be capable of blowing your Pioneer away as far as sound quality goes. Good luck.

 

[Shockwave]

I was thinking 125 db/ 2M was way high. Highest I have ever heard of was around 105 DB / 1M - 1W but I dont follow home audio all that much so wasnt sure how accurate that was and wasnt going to say anything.

 

[Priit]

Well, you can always connect two of your 4 ohm speakers sequencially on one channel so they make up 8 ohms but that way you only got two channels...

 

[tcsenter]

My Kenwood receiver has a little switchy thing on the back to select between 4 and 8 ohms.

 

[tcsenter]

The best thing to do would be to consult Pioneer's specifications/manual for the receiver. Send their tech support an email if necessary.

Some receivers/amps are designed to be 4 ohm stable with impedance automatching, most are not. Unless you have some clear indication, the only way to know for sure is to consult the product's specifications/manual or manufacturer. We can probably guess: consumer level Pioneer = probably not.

Given that your speakers are reasonable quality and efficient, you could probably get away with it as long as you don't crank the volume up and you ventilate the amp well.

Also, 4 ohms may only be the published minimum rating of your speakers. In reality, they may have a slightly higher working impedance, around 5-6 ohms. This is often the case.

If you're that concerned about it, and don't want to buy new speakers, look for an impedance autoformer to connect in-line between the speaker and amp.