Hi everyone,

I'm looking to finally get some decent speakers for my amp (a Yamaha RX-V350 if I remember rightly!)

The amp has 6ohm speaker terminals. Now, I'm looking to begin by buying a Mordaunt-Short 905i centre speaker. This speaker's specs list an impedance of 4-8ohms. Initially I thought 'great!' -- 6ohm of my amp is right in the middle of that range.

Then it occurred to me -- these speakers are bi-wireable. So, I'm supposing that it's either 4ohm or 8ohm, depending on if it's used in a bi-wired fashion or not.

Now, my question is -- is the above the case? Does the speaker cause 4ohms of impedance when single-wired, and 8 when bi-wired? Or is it round the other way? If my amp's only 6ohm, am I only able to use the speaker in one particular wiring fashion? Or is the speaker completely unsuitable?

Many thanks,
Chris

Bi-wired or single wired the circuits are electrically identical. Adding a second cable and removing the jumper does not change the impedance seen by the amplifier.

You can test this to an extent by measuring the DC resistance of the speaker in both bi-wired and single cabled modes. Excepting the small reduction from doubling the wires, the values will not change.

All dynamic speakers have an impedance that varies with frequency. The impedance specification for speakers is a nominal figure not an exact value. However it is true that the average the impedance of an 8 ohm speaker is higher than that of a 4 Ohm speaker.

Most receivers rated at 6 Ohms can safely drive most 4 Ohm speakers.

Thanks very much for your help, trekguy.

I'll do a bit of research around the web to see if anyone's happily using the speaker I'm considering with my particular amp. Are such questions welcome on these forums? I see you're all quite technical here and I'd hate to barge in asking 'newbie' questions (although, admittedly, in this area I am something of a newbie!)

Cheers,
Chris

Most of us started as new guys. :) Some of us will always be new guys ;)

Very true :)

Can I just ask another quick question on this topic. I'm suspecting that a lower impedance makes the speaker 'easier' to drive for the amp. So, in this case, with the amp smack-bang in the middle of the speaker's range, it'll be the case that certain frequencies will be taxing the amp, whilst others will be 'too easy' for the amp? So the end result would be that some freqs. are quieter whilst others are louder? Assuming there's no danger to either the amp or the speaker in this configuration, would the imbalance be discernible or easily compensated with some EQ tweaking on the amp?

Apologies if I'm way off-base... just curious :D

Cheers,
Chris

I'm suspecting that a lower impedance makes the speaker 'easier' to drive for the amp.

It doesn't, it's the opposite. A low impedance is a heavy load.

I've clearly got some reading to do :)

Thanks, Targus!