What is an Active System?

Posted by: Adam Meredith on 17 October 2006

From the Products Section.

"Simple: it's the opposite of a passive system.

In a passive hi-fi system the job of dividing up music's high, middle and low frequencies so that they end up at the appropriate drive units in the loudspeaker is performed by an electrical filter network in the speaker. The power amplifier sends the loudspeaker a signal that contains all the high, middle and low frequencies and the speaker's crossover network sorts them out. This works but it's not ideal for systems that aim to deliver cutting-edge performance. [There are sound technical reasons for this but we'll refrain from boring you with them.]

We believe that the best way to do the job is to intercept the musical signal as it leaves the pre-amplifier and use a powered [active] crossover (an electronic filtering network) to separate the highs from the mids and the lows. This, naturally, means that we need to use more power amplifiers: one for each band of frequencies. And more loudspeaker cables, of course: one from each amplifier to its dedicated loudspeaker driver connection.

This is, of course, more expensive than any passive system arrangement but we are convinced - as are many satisfied customers - that the results justify the additional expenditure. Active systems typically sound more precise, clear and controlled than passive systems. The result is music that sounds more like music and less like a hi-fi system. In part this is because active systems inherently produce less distortion than passive systems. [Sorry, for being technical but it's a fact!]

We have, throughout our history, always ensured that our systems can be easily and cost-effectively upgraded to active operation.

Finally, for what it's worth, bi-wiring and bi-amping do not, whatever the hi-fi press or any other manufacturer might tell you, provide similar performance to a [properly designed] active system. Any of our franchised dealers will be more than happy to demonstrate this to you.

In practical terms . . .

In a system using two-way loudspeakers, such as the SL2, upgrading to active operation means using two stereo power amplifiers or four mono amplifiers, a Snaxo 242 crossover and a power supply. In a system using DBL loudspeakers, we need three stereo amplifiers or six mono amplifiers, a Snaxo 362 crossover and power supply."


Naim make their active crossover for their range of speakers and a small number of previously popular (Linn mainly) designs and some "special" commissions.

However, in order to design an active crossover one needs - crossover frequencies, filter slope and relative driver efficiencies. These, alone, do not guarantee a worthwhile result and I would suggest that such a project is best undertaken entirely in the DIY sphere - any Naim "solution" being both expensive and provided entirely on a "best fit to provided parameters" basis.
That is - we could not become involved with any further fine tuning, refunding or ongoing involvement with the project.

A one-off is very much outside our normal R&D and production schedules. I would imagine that, as when last I discussed this, a substantial charge would have to be made, a full payment received and an agreement to no refund (unless faulty).

I would not recommend this course of action at all.

For one-off "projects" - get yourself a active crossover kit with instructions on how to tailor parameters. Then muck about to your heart's content.

Bi-Wiring (NOT Active)

"Why does Naim not agree with bi-wiring and tri-wiring passive loudspeakers?

It's true that we are not great fans of multi-wiring passive loudspeakers in accordance with current vogue. Our belief is that if the crossover has been correctly designed, a single run of cable between amplifier and loudspeaker offers the best sound, as well as making it easier for the amplifier to drive safely.

Obviously, if the speaker crossover has been deliberately designed to sound better when bi- or tri-wired, then it quite possibly will; but that's not to say that it wouldn't sound better overall if it were designed for single wiring in the first place, as our speakers are."

In Addition:-
No Naim speaker is suitable for bi-wiring.
OR - If you have removed the passive crossover (without introducing the correct active crossover) and connected two channels of amplification direct to the revealed sockets - you run a VERY high risk of damaging the treble units and producing a really 2nd rate sound.
Please don't try this - it is wrong.