Question about speaker ohms and amp compability

[mattamatikk]

Hello there.

So, I have a NAD d3020 amplifier standing on my desktop. It is rated 30w in 4 ohms. My question is, which of these speakers will be easiest to drive for the NAD:

1. Dali Lektor 1, 8 ohm and 84db

2. Dali Menuet, 4 ohm, 86db

Will the 4ohm speaker be harder to drive? Im confused. Which would pair best with the NAD?

 

[Vladimir]

Technically I would go for the Menuet because of the extra efficiency. They should go louder than the Lektor because of extra 2dB and the nominal 4 ohms sucking more watts from the amp. Neither of these two speakers should be a very difficult load impedance wise.

However, if i was to spend that money you saved up, I would just buy the speaker that sounds best to my ears. Loudspeakers being transducers are too much matter of subjective taste, and manufacturer specs are all scribled with crayons (rough and not to be taken too seriously).

 

[Al ears]

+1

Go find a dealer and audition both. Don't get too bogged down in figures.

What led you to this choice in the first place?

If you're still concerned try the Dali Lector 3, 88dB and 6 ohm.

 

[lindsayt]

Vladimir, if we are to take the specifications at face value, the lektors are in fact more efficient.

Why?

They are 8 ohms 84db/2.83volts@1 metre efficient. Which is 84dbs/1 watt @1 metre efficient.

The Menuets are 86db/2.83v@1metre efficient. But they are 4 ohms and will be sucking twice the power from the amp. So we need to subtract 3dbs from their efficiency to compare them to 8 ohm speakers, making them 83dbs/1 watt @ 1 metre efficient.

Having said that, in the real world, the impedence of every speaker depends on the frequency being fed to it. And quoted impedance figures are rough nominal averages. Also, as a look at a few Stereophile speaker reviews will reveal, manufacturers often quote inaccurate efficiency and impedance specifications.

When you get amps where speaker impedance becomes critical: IE SET amps. It's the minumum impedance that is more important than the average / nominal impedance. And we don't know what that is for either of the speakers.

The OP's NAD amp should be able to cope with the impedance of either speaker, as long as their impedances don't dip to something stupid - ie around 1 ohm.

So, the better speaker for the OP then becomes (as Vladimir quite rightly pointed out) the one that he prefers the sound / looks / price of. There are, of course, hundreds of other speakers that might suit him even more.

 

[Vladimir]

That is true. However, when you compare the 4 and 8 ohm speaker you presume the 8 ohm Lektor will play at 4 ohms and at that load be more efficient. What if it never goes under 5 or 6 ohms? It's declared as 8 ohms nominal after all.

 

[mattamatikk]

Hi, thank you all for answering.

I do have the lektor 1, and been having them for a year now, and they are great, but I feel like an upgrade, but I dont want to lose power because the NAD wont drive the lektors to high volumes. Im using them in a desktop matter, and have the volume 2-3 o'clock when I want to play loud. The lektors are small, and fits into my dekstop setup just right, and so are the Menuets. If you have other suggestion with about the same size I would be happy if you shared it.

 

[Al ears]

The above may be true but bearing in mind the OPs size restrictions it is unlikely we could specify a more efficient speaker, particularly from Dali. I quoted the 3s before these limitations were mention. Perhaps the OP needs to audition.

 

[Jota180]

Your having to go by the manufacturers numbers which may be on the generous side.

 

[Rethep]

They are 8 ohms 84db/2.83volts@1 metre efficient. Which is 84dbs/1 watt @1 metre efficient.

The Menuets are 86db/2.83v@1metre efficient. But they are 4 ohms and will be sucking twice the power from the amp. So we need to subtract 3dbs from their efficiency to compare them to 8 ohm speakers, making them 83dbs/1 watt @ 1 metre efficient.

That is incorrect! The definition says: Efficiency in dB measured at 1 Watt (at 1000Hz) at 1 metre. With an 8 ohm impedance that gives 2,83 V (U^2/Z --> 2,83^2/8= 1 Watt). With 4 ohm, 1 Watt it gives 2V (2^2/4= 1 Watt). 2,83 V over 4 ohms would give 2 Watt!

Most SS-amps give more power in 4 ohms if the higher current, the load draws, can be delivered!

2 dB difference in efficiency is negligible!

Of course the impedance is freq. dependent. So especially the speaker that goes deeper in bassfreq., where the lowest impedance is usually measured, should be auditioned critically in that area!

That concluded makes auditioning the only way to make the best choice!