Unitilite Lite

Coll, I believe that as a general guide, for most Naim amplifiers they're happy down to a minimum impedance of around 2 ohms before triggering their protection.  Of course, that means little with regard to what speaker is best matched to a Unitilite.

Should read ohms not ins due to my tablet not understanding

I sent a quick email to Naim and surprisingly they said it is best to use 4 ohms as a minimum.

I can connect the speakers in parallel as there are 2 full range drivers in each cabinet but that then gives 12 ohms minimum I suppose that will then be ok.

I have used Rega RS3 with my unitilite and have no complaints 

Coll posted:

I sent a quick email to Naim and surprisingly they said it is best to use 4 ohms as a minimum.

I can connect the speakers in parallel as there are 2 full range drivers in each cabinet but that then gives 12 ohms minimum I suppose that will then be ok.

I thing you mean in series =12Ω, presumably the two speakers each having a minimum of 6Ω, and so parallel min is 3Ω.

Given Richard's contribution I suspect that when Naim said best to use 4Ω as a minimum they meant nominal impedance rather than actual, in which case the parallel connection would be fine (I'm guessing the nominal for each is 8Ω, so nominal in parallel is 4Ω?). But check with Naim if you're in doubt. However, as long as the amp would not be damaged if the impedance is too low, but instead perhaps have the annoyance of protection circuitry kicking in, then there would be no harm trying in parallel first and only changing if indeed it i=gives problems.

N.B is your impedance measurement the free air of the driver by itself, or mounted in the specific enclosure you're using? They may not be the same... 

EBT posted:

I have used Rega RS3 with my unitilite and have no complaints 

 

What is the minimum impedance for the RS 3

Innocent Bystander posted:

Coll posted:

I sent a quick email to Naim and surprisingly they said it is best to use 4 ohms as a minimum.

I can connect the speakers in parallel as there are 2 full range drivers in each cabinet but that then gives 12 ohms minimum I suppose that will then be ok.

I thing you mean in series =12Ω, presumably the two speakers each having a minimum of 6Ω, and so parallel min is 3Ω.

Given Richard's contribution I suspect that when Naim said best to use 4Ω as a minimum they meant nominal impedance rather than actual, in which case the parallel connection would be fine (I'm guessing the nominal for each is 8Ω, so nominal in parallel is 4Ω?). But check with Naim if you're in doubt. However, as long as the amp would not be damaged if the impedance is too low, but instead perhaps have the annoyance of protection circuitry kicking in, then there would be no harm trying in parallel first and only changing if indeed it i=gives problems.

N.B is your impedance measurement the free air of the driver by itself, or mounted in the specific enclosure you're using? They may not be the same... 

Yes sorry did mean parallel impedance.

The Impedance for each driver is 6 ohms between 200hz and 600 hz so 3 ohms in parallel.

Got the figures from a graph on the Jordan Speaker website.

Nominal is 6ohms 

Just to be clear as you've been asking me the same on email ...

We recommend speakers with a nominal impedance of 4 - 8 ohms ... a nominal impedance is not the minimum impedance of a speaker however, it's basically an average impedance across the audio bandwidth. For example a 4 ohm speaker will generally tend to vary between maybe <2 and >15 ohms depending on frequency and enclosure design but it's a general guideline.

We normally build our amps to be able to be stable into a 2-ohm load but we wouldn't recommend using a pair of 4 ohm speakers in parallel on each channel (or a 2 ohm speaker if they can be found) as that really is putting a lot of strain on an amplifier and this is a UnitiLite that you're talking about ... something like a NAP 250 / 300 / 500 will have a much healthier current delivery into awkward loads.

So it's not just a case of driver 'x' being 6 ohms nominal and 3 ohms in parallel and that's part of the skill of speaker building - making a speaker that sounds good and actually presents a sensible load for the amplifier to drive...

Phil

Hi Phil

Thank you for posting I was just about to do a post saying that I had heard from you and that all was cleared up so I don't need to do that now.

As I said in my post earlier the lowest impedance will be 3 ohms so no problem.