4/6 Ohm receiver necessary?

[mudrummer99]

I was just thinking about this. If you have a pair of 4 Ohm speakers with a higher sensitivity, say around 95dB or so, do you need a 4 Ohm stable receiver? Especially if you listen at moderate levels and don't push them hard? Thanks for indulging my question.

Mike

 

[lsiberian]

I was just thinking about this. If you have a pair of 4 Ohm speakers with a higher sensitivity, say around 95dB or so, do you need a 4 Ohm stable receiver? Especially if you listen at moderate levels and don't push them hard? Thanks for indulging my question.

Mike

Yes. Ohm stability is very important for LFE response. If you have poor stability down there then you could have a lot of issues.

I don't know of any speaker that's a nominal 4 ohm with 95db sensitivity.

 

[mudrummer99]

Thanks, it was mostly theoretical. I was just curious if Ohm stability was based on power draw or not, guess not. Thanks again.

Mike

 

[PENG]

Thanks, it was mostly theoretical. I was just curious if Ohm stability was based on power draw or not, guess not. Thanks again.

Mike

It most certainly depends on power draw. For argument sake any receivers should be 4 ohm stable if you only draw milliamps from them. That is, you have the volume turned right down to say -50 or lower. Even if you draw some real power, say 2 watts, a $500 receiver will still be 4 or even 2ohms stable. By the way, in a HT set up, most people use a powered subwoofer to take care of LFE so the receiver does not have to deal with those low frequency power draws.

You asked a theorectical question so I hope you don't mind a theorectical answer.

 

[lsiberian]

It most certainly depends on power draw. For argument sake any receivers should be 4 ohm stable if you only draw milliamps from them. That is, you have the volume turned right down to say -50 or lower. Even if you draw some real power, say 2 watts, a $500 receiver will still be 4 or even 2ohms stable. By the way, in a HT set up, most people use a powered subwoofer to take care of LFE so the receiver does not have to deal with those low frequency power draws.

You asked a theorectical question so I hope you don't mind a theorectical answer.

Just to clarify the subs typical area doesn't cover all the lowest impedance dips in your speakers usually. The range of the dip depends largely on the drivers used, but anywhere from 500hz to around 50 hz is usually the impedance bottom. So if you have 4 ohm nominal speakers I do suggest you use an external amp like a Behringer A500

I think it's better to be safe than sorry with electronics.

Of course an amp can handle a small load even with a low impedance, but you better realize that in home theater spikes are common.

If you are using a solid amp like an Onkyo 805 or higher I see no real danger.

 

[PENG]

Of course an amp can handle a small load even with a low impedance, but you better realize that in home theater spikes are common.

If you are using a solid amp like an Onkyo 805 or higher I see no real danger.

Agree, but please note the last sentence in my post.

 

[3db]

I would like to chime in that low impedance isn't enough information to go on. Where in the frequency response does that dip occur and what is the phase angle at where this dip occurs? If the phase angle is small and the frequency above 80 Hz, you can pass on a the requirement of a 4 ohm stable amp.