I am the proud ownner of two pairs of vintage Naim speakers: one pair of SL2’s and one pair of DBL’s. Currently, I am using them with their passive X-overs, but I intend to experiment with active mode.
One important issue with that: at this point in time I am not using Naim amplification but rather a different brand that I don’t need to name here (pun unintended). These amps can in fact be customized for active amplification (high-pass, low-pass, band-pass, slope, phase, etc) .
The only problem I have is to find the right parameters for such customization. Someone suggested I get hold of adequate SNAXO’s and measure their output. Unfortunately this would be too expensive, so I hope that someone will be able to let me know the values of the most important parameters.
If you look for Devialet Naim Active on Google, you’ll find your own postings elsewhere (I read it in the time, so I recognized you). There are people using sl2 pxo’s on sbls so their crossover point should be the same or similar.
Halibut is as usual right and Naim is likely to help you.
The two important things are the crossover frequency/ies and the slopes (e.g. 18dB/octave, 3rd order as the information you have found). For everything else get yourself a copy of REW software (free of charge), and a measuring microphone (the one recommended by REW I think is under £100 and is good). With that you can assess the actual phase response (time delay) and adjust the crossover until optimised, balance the channel levels, and try whatever available slope characteristics (e.g. Linkwitz-Riley, Butterworth) gives you the best response. N.B. If alternative slopes are offered, be wary of using a less steep one as it will allow more energy to the tweeter with the potential to cause damage - but you can try a steeper slope such as 24dB/octave, which will not do harm, and using REW you can assess if it seems beneficial as well as using your ears.
As a bonus you can use REW to aid choice of best speaker and listening positions in the room.
@anon4489532: Yes, I suppose they will be kind enough to help me even though I am not using their amps at this time. Thanks.
@Ardbeg10y: You are right, but in those older postings, I was assuming that the crossover freqs mentioned in the SNAXO 242 manual do apply to SBL’s (and SL2’s), although this is not said explicitly. Moreover, I was disregarding other parameters such as phase shift.
@ Innocent_Bystander: Thanks for the tip: this is really useful!
