Running 4 Ohm speakers on a receiver

Schris22

Quick question.


I have an onkyo sr 502 and am looking at some new speakers a few are 4 ohm and well. The manual says I should only run 6 ohm and up. Is this in all cases? or just a big safety net. i never plan to push the speakers and my room will be 11 and a half by 16 feet so it's tiny. I never push it because i live in a dorm. I'm not planning to upgrade my receiver for a while. I feel my weak point is my speakers *see sig*



Thanks,

Chris

jakelm

I have the same reciever, Chris. I have not found 4ohms to be a problem on any channel. The front left and right rate stable down to 3.

P.S It is the tx-sr502 right? Not a sr-502-s or what ever you posted.

unc2701

Ultimately you'll want something that can truly push 4 ohms, but you should be fine for now. In such a small room, you're probably not going to push it hard enough to trigger the thermal protection. Just don't hook anything to the "B" posts. If you do have problems, putting a fan on the reciever should give you a little more space before it craps out.

organ

I once pushed my LSi9 with an Onkyo receiver. It didn't shut down. But if you plan to get those speakers, you will eventually have to get seperates later on or else you won't hear what they're capable of.

The receiver will power them but sound quality will suffer compared to a dedicated amp that can push 4 Ohms.

jakelm

I ran that reciever front left and right channel at 2ohms center and surrounds at 4ohms at ref level for 3.5 hours through LOTR and an additional 2 hours with music. The 502 did not miss a beat.

michael_w

As others have already said, it'll work but it won't sound as good as it could. If you're talking about the LSi series it seems almost wasteful to run them off a receiver because they're capable of so much more. I had my 7's running off a low end panasonic avr and didn't have any issues unless I wanted to push them.

It might not be a bad idea upgrading now and then later down the road when you're not stuck in a dorm and can finally unleash them you can go out and buy something that can handle a 4 ohm load.

Schris22

thanks for the advice guys. I just didn't want to rule off totem, epos, LSI's off my list...

I'll definatly be looking to upgrade, probabaly in a few years when the high definition audio from Dolby digitial (HD-DD?) and the DTS whatever comes out.

Chris

SuperDave

The Lsi 25's would shut my receiver down if set to large. They worked ok on small with the sub preouts driving the low end. I ran that way for a year until I got an amp. So you can do it.


SuperDave
Yamaha RX-V992 (Center,Rears)
Adcom GFA-5500 (Main)
Denon DVD-1920
Sony XBR 27"
BrightHouse DVR
Polk LSi25 Main
Polk LSiC Center
Infinity RS1 Rears
Monster THX Cables

Schris22

well i'm just looking at bookshelves but well it's good to know it's possiable.

Thanks

Chris

Tour2ma

Anything is possible...

If you do encounter the AVR going into protection mode (thermal/ high-temp shutdown), you'll just have to back off the volume setting a bit. As SD said, a sub can help by lightening the AVR's load some.

Do not think you can add a fan to help keep it cool. While that may keep it cool enough to avoid going into protention, excessive heat is still being generated... and that ain't good.

Schris22

I'm sure I could obtain a small fan to put in the space. i'll ask the guy if an in home trial is possiable. Never even though of that. There is no fan on it now but never seemed to get too hot.

Chris

heiney9

Tour2ma wrote:

Do not think you can add a fan to help keep it cool. While that may keep it cool enough to avoid going into protention, excessive heat is still being generated... and that ain't good.

I agree here. It won't nec. be the heat that shuts it down. Most if not all receivers of this type have current limiting circuits that will shut the unit down even if it's kept cool by an external fan.

That being said, it will probably power a 4 ohm load to reasonable levels but as others have stated it won't allow you to get the "most" out of the set-up.

H9

unc2701

Since it's not shutting down now, it might be a non-issue... but you guys are right- the fan might not do much. Most AVR's have 3 kinds of protection: thermal, distortion and current. If I know anything about dorm-room setups, the thermal is gonna hit first (tight spaces, not enough ventilation), so the fan will only get you a little more power till the next one hits- probably current limitation. It's gotten me a little more juice out of both an Onkyo & Yammie, plus some guitar gear.

Tour2ma

unc,
Chris ain't there yet. Couple others chimed in that their similar rigs are doing OK...

chris,
Please reread what I wrote, and h9 seconded. A fan is a bad idea.

My original phrasing may have been a bit awkward, but the jist of what I said is don't use a fan thinking it will make things OK. A fan only treats a symptom, not the cause.

Then again your AVR's performance pushing 4-ohms may not be an issue in your room at levels you find satisfying.

jakelm

A fan might even cause a slight humm in the system if it isnt hooked up perfectly. Dont be afraid of 4ohms. On most amps especially Onkyo, trouble doesnt hit till you get to 2ohms. And remember, the Onkyo's specs say that it has Dynamic Power down to 3 ohms, so why worry.

unc2701

The cause of the heat is the amount of current moving through the transistors. If you can keep transistors cool, you can push however much current you want through them without damage to them. Think class A amps, or overclocking a computer. The problems are:
1)they will start to distort the signal and
2)They don't have an infinite amount of current available

As H9 mentions, the current will get tapped out- usually well before the you get damaging distortion, AND AVR's protect against both. Active cooling is only a bad idea if you can't stand the fan noise or you get hum from the motor.

As I've repeatedly stated, mileage will vary on this solution. Sometimes, the current hits the limit before the heat. However, good ventilation is a cheap solution worth investigation IF you have issues.

Schris22

Ok i'm starting to understand a bit better now.

I'll just have to wait and see if the totem dealer will let me try them out and see how hard i need to push them in order to get them to "acceptable" listening volumes.

Chris