Active crossovers?

[AngelEyes]

Salutations,

I know Nimby uses one, what circumstances would you use one and what is so good about them?

Thanks.

Adam

 

[parky43007]

This is what Linn state on there websiteÑ

What is Active (Aktiv) and what difference does it make?
The removal of the passive crossover from the circuit path and more closely coupling the drive unit to the power amplifier results in better and more accurate control of the loudspeaker’s drive units.
When using a passive crossover, the power necessary to operate the crossover is actually provided by using part of the energy in the musical signal. With Aktiv operation, all signal processing is done in an active (i.e. powered) circuit prior to final amplification, eliminating the power drain caused by the passive crossover. In addition, shaping and controlling the signal while it is still at line-levels provides the opportunity to use significantly more sophisticated crossover techniques. This results in better filtering and more accurate amplitude, phase, and time response. The flexibility of an active system also enables the system to be tuned to suit the room.
The end result of an upgrade to Aktiv will be quite simply a breathtaking improvement in sound quality.

 

[HiFiRuss71]

You would use active crossovers either in an active system (one amplifier per drive unit) as suggested above, OR a normal pre-power stereo system to separate out the bass before it reaches the power amplifier in order to send it to a sub. This latter implimentation is the way Nimby is doing it IIRC.

Not much point for straight multichannel systems like ours, because bass management is already performed in the receiver/processor.

Russell

 

[Nimby]

Using an active crossover with a speaker already furnished with a passive internal crossover will not offer the potential benefits mentioned by Linn. You would need to feed the separate drivers each with a dedicated amplifier at suitable crossover frequencies to have a true active system.

That said, the active crossover allows a steeper roll-off without the serious impedance and DC resistance problems using a passive crossover in series with the bass driver. A high quality passive crossover at typical subwoofer crossover frequencies would require massive coils of very thick copper wire and huge capacitors. The crossover frequency would also be fixed.

A higher roll-off (than the speaker is usually capable of) offers the benefits of lightening the bass load on the speaker and its amplifier.

I only ended up with an active crossover between my IB and floorstanders because I wanted to use my system primarily for stereo rather than 5.1.

An active crossover offers considerable flexibility. Having continuous rotary controls for frequency and +/- for gain rather than the usual stepped arrangements hidden in the menu of an AVR. Muting of each of the four channels is as easy as pressing a button.

 

[AngelEyes]

Thanks chaps, interesting stuff and of no use to me by the looks of it

Adam

 

[tony @ suffolk]

My Naim pre/amp/speaker combination uses an active crossover. This has it's own power supply (as is Naim's wont) & feeds two NAP 250 amps.

The Naim SBL loudspeakers have a detachable passive crossover unit at the back, so can be used in either active or passive form.

One of the pleasures in owning Naim stuff is its upgradeability (OK, you have to give up eating & send the kids out to forage in the hedgerows to be able to afford it), and when I upgraded from passive to active I was amazed at the difference it made. I guess Linn's "breathtaking" comment is about right, and indeed I struggled to get to grips with the change for a while.

Was this because the previous passive set-up was lousy? Not at all, in fact I would have continued quite happily with this, in blissful ignorance, if I hadn't gone for that fatal demo...

 

[HiFiRuss71]

Just to clarify, Angel Eyes originally query involved an active crossover NOT active amplification. Although active amplification requires an an active crossover, the reverse is not true.

Having worked at a Linn dealer for a few years, some while ago, I have always respected the 'modular' upgrade path offered by the once bedfellows of Linn and Naim and I'm surprised that more manufacturers, with a full source to speaker product line, haven't gone down this route.

Of course, with their one amp fits all approach, they're all amateurs compared to the kings of active speakers - ATC.

Russell

 

[tony @ suffolk]

Of course, with their one amp fits all approach, they're all amateurs compared to the kings of active speakers - ATC.

Russell

If for some reason my whole system spontaneously combusted, think I'd probably go down the ATC route Russell!

 

[HiFiRuss71]

Sorry, I would have replied sooner but I needed a break halfway through reading your kit list. Which small banana replublic had it's national debt cleared, due to the sudden upsurge in copper ore prices, when you cabled that lot?

Russell

 

[Nimby]

Sorry, I would have replied sooner but I needed a break halfway through reading your kit list. Which small banana replublic had it's national debt cleared, due to the sudden upsurge in copper ore prices, when you cabled that lot?

Russell

Perhaps that's really the answer to clearing African debt?

They should not sell their raw copper ore but make only high end cables instead!

 

[HiFiRuss71]

The first person to create a pun based on banana plugs gets a slap.

Oh! It was me. Gutted.

Russell

 

[Nimby]

Very festive Russell!

I have been wondering what the hell your avatar represented for longer than I care to admit. Usually I'm good at recognising almost anything from any conceivable angle.

Russell, your Horse Chestnut bud seems to be wearing a silly Christmas hat.

 

[AngelEyes]

I notice IanJ is sporting similiar apparel! Luckily there is no room in my Avatar for such frivolity

 

[Nimby]

 

[AngelEyes]

LOL this is the only forum where such offtopicness (new word) goes mostly unmoderated

 

[recruit]

LOL this is the only forum where such offtopicness (new word) goes mostly unmoderated

It is Xmas Angeleyes & the Sub Forum is one of my favourites because of the diversity of members even ones who look like Lee Van Cleef with pink earings

 

[AngelEyes]

I would hate to do a statistical analysis but I suspect that threads started by this 'AngelEyes' character seem to have more than their fair share of off topic gibbering, and not just by the OP...

 

[paulst10]

It is Xmas Angeleyes & the Sub Forum is one of my favourites because of the diversity of members even ones who look like Lee Van Cleef with pink earings

LOL very good

 

[AngelEyes]

That is the last time I let Nimby take my picture after a few drinks

 

[HiFiRuss71]

I would hate to do a statistical analysis but I suspect that threads started by this 'AngelEyes' character seem to have more than their fair share of off topic gibbering, and not just by the OP...

Who are these people who disrespect the OP with such ramblings?

Russell

 

[AngelEyes]

Who are these people who disrespect the OP with such ramblings?

Russell

I am not sure but they must be fairly chummy with the moderators; I suspect it is a global conspiracy to camouflage my otherwise incredibly useful and informed posts...

 

[recruit]

Who are these people who disrespect the OP with such ramblings?

Russell

You can talk Chestnut with that silly red hat

 

[HiFiRuss71]

Ah! There's one.

Russell

 

[recruit]

Ah! There's one.

Russell

I know Russell but when i read Nimbys Quote...

Russell, your Horse Chestnut bud seems to be wearing a silly Christmas hat.

I nearly fell off my chair laughing

 

[HiFiRuss71]

Yes, when they've got him on the right mixture, he's a national comedy treasure. By Danish standards.

Russell