Active Oddness

Posted by: Tim Danaher on 09 January 2003

Just gone back to active (3 x 250s / Briks) after selling the 135s that were driving the tweeters. For a month or two I'd been running the briks passively using one, then two 250s (i.e. in '125' configuration.

I thought that my dissatisfaction before selling the 135s was due to their mismatch with the 250s -- treble harshness and a 'mechanical' sound. Using the 250s I was getting what I wanted -- beautifully smooth, detailed sound, all the 'CD nastiness' had gone (esp. with CD5 / Flatcap2), and I couldn't wait to get back to a balanced 250 tri-amp: the treble was just sooooo good on the passive set-up. The sound was fluid and organic and wonderfully musical. I wanted more of the same.

After setting it all up again last night I found I was back to the same position as before. With the NAXO set flat, I'm getting LOADS more detail, a 'faster' sound but less bass (definitely NOT 'absence of overhang') and a harsh treble sound, to my ears.

Do the NAXO and the new 250 need to warm up? Do I need to change the tweeters in the Briks (they ARE old HiQuphons) or is this sound a facet of active operation? Somehow, I don't think that tweaking the NAXO will get me what I want. The whole nature of the sound has changed.

Sorry if I've rambled on here, but any observations or comments will be most welcome.

Cheers,

Tim
_____________________________

Os nid Campagnolo yw hi, dyw hi ddim yn werth ei marcho...
Posted on: 09 January 2003 by Thomas K
Hi Tim,

Have you sited the NAXO and its Hicap properly (NAXO away from trannies, Hicap on a decent support)? I've found this to be very important for the tonal performance of the sistem.

Thomas
Posted on: 09 January 2003 by Bosh
Yes the NAXO does require extended warm up (5-7 days as with a pre-amp) but unless the 250 is new, warm up of that should not be an issue after 24 hours.

I too noticed a lot more bass in passive mode with SBLs. Let the NAXO warm up then try increasing the bass pot (and/or decreasing the treble pot) on the NAXO. Once set provisionally let it settle over night before making further judgements. I also found the SBLs needed re-positioning (wall to speaker, toe in and separation) to get the best from them in active mode too
Posted on: 09 January 2003 by Tim Danaher
Thanks everyone. I'll see how things settle down after a week. And I think the tweeter replacement is a must...

Cheers,

Tim
_____________________________

Os nid Campagnolo yw hi, dyw hi ddim yn werth ei marcho...
Posted on: 09 January 2003 by Willy
Tim,

Replaced my tweeters with the original Hip's last year to great effect. Removed a lot of harshness and returned more detail. Just before Christmass one of the mid's developed a buzz so I've sent them all of for re-build. Noticed on removing them that the cone suspension on another one separated very easily so I guess they were in need of attention.
Hope the bass units hold together as they look like a b***er to remove!

Regards,

Willy.
Posted on: 09 January 2003 by Martin Payne
quote:
Originally posted by Tim Danaher:
is this sound a facet of active operation?



Tim,

when active briks are working right, they are much smoother and cleaner than passive.

The bass is also leaner in a 'less is more' sort of way.

cheers, Martin
Posted on: 10 January 2003 by Willy
quote:
Originally posted by Mark Russell:
Willy,

Where did you send your midranges to be rebuilt?
What is the cost?

Mark Russell


Mark,

Sent them off to Wembly Loudspeaker in London (www.wembleyloudspeaker.com). Picked this contact up from another thread some time last year. They've to phone and confirm the final cost but said it should be max of £32 + tax per unit. Turnaround time is 7-10 days.


Regards,

Willy.