Active crossover built into Class A

[planet10]

Dali Helicon 800Mk2

Quick search did not turn up an actual XO, but did find a Dali 800 revised XO by Troels. nHe knows what he is going.

Your speaker is quite different, but if the XO bits here are in anyway representative, you have a first order lowpass on the woofer, the XO for the midrange has more to it.

Unless you have 8 amplifer channels you’d have to be part active and part passive. That would mean at least disturbing the passives enuff to measure the relevant components, so that you can recreate the parts of the passive you want to continue to use (i would expect at a higher level of parts quality). Means the XO has to come out if you want to do what you want.

In my situation what would you do.

I have opened up and hacked loudspeakers pricier than these (inflation adjusted), so would have no fear at going inside.

But it is not really my taste in loudspeakers so i would sell them and use the proceeds to build something better specifically to by multi-amped. These for instance.

dave

 

[Gizmoand]

theres abselutely no way ill ever sell those. 😀 they are the finest pice of audio hardware i have ever heard...
but i respect you for saying your opinion.
i was using a nad t765 and nad c272 to drive them. thats why i wanted to build the amp..
im never going to open those pieces of art up.. ever.. ill press on and just do the biamping without crossovers and take it from there

 

[batteryman]

There is no harm in filtering oput frequencies that are filtered out by the passice crossover but make the active filters operate over a wider bandwith - ie not at the same crossover frequencies.

Also, since the passive crossovers will block unwanted frequencies, the load on the amp is reduced outside of each driver's range. I.e no power is wasted or the crossover would heat up (obviously).

I don't thinkl there are sonic benfits by using active crossers when the speaker has passive ones. (My Naim SBLs have their crossovers mounted externally because Naim intended them to easily removeable and used with their active crossovers)

 

[EUVL]

For the 400 Mk. II, from Stereophile.


Patrick

 

[EUVL]

Plenty of pictures here :
https://hifi-inside.com/speakers/dali/page-3-4

Patrick

 

[EUVL]

And the Dali 800 mentioned at the Troels webpage does not seem to be the same as the Helicon 800 Mk II


Patrick

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[EUVL]

Seems easy enough to have access to the crossover without any detriment to the speakers.
A simple frequency sweep with a chipamp will allow you to measure the transfer function at the crossover outputs without having to have any knowledge of the speaker chassis.
You can then design the active crossover to emulate that.
Should also be easy enough to rewire.
But you will need 6 Speaker terminals per speaker and 6 channel power amps for stereo.
Easiest is a new plate for the terminals.
Then you can restore it back to original status anytime.


Success,
Patrick

PS Crossover components not particularly high-end, if I may say so.

.

 

[J247W]

So what you are saying is. Get active crossovers that is 1000 ish hz for bass and 700 ish for highs?

You need to know what the crossover points are, so in the IXI (X is the roll off & on points) bit you want to be further along & no were in the IXI crossover points, after (I) on each side of the roll off, so it does not add or subtract from the crossover point?.