Going active with a 2 way speaker (Naim SBL's)

[Waiski]

Good to hear it worked. I suggest you to do acoustic measurements with skilled person and do the fine tuning of phase and crossover. It will give you even more.

I have 4 way system and would be interesting to do it with 4 Devialet. At the moment I am biamping with 2pcs of 250 Pro. Bass is totally without passive crossover, mid is without passive high pass. Crossover, phase and levelling between bass/mid is done by Devialet. Hight pass is 1st order and low pass is 3rd order.

[pisabell]

Hi watchnerd,

In your thread about 3-way active systems, someone said Devialet could configure a 3-way setup for you. Did you check with them?

I hope there is a way to do that because, judging from my experience with a 2-way speaker, going active is a must!

Pierre

[watchnerd]

Hi watchnerd,

In your thread about 3-way active systems, someone said Devialet could configure a 3-way setup for you. Did you check with them?

I hope there is a way to do that because, judging from my experience with a 2-way speaker, going active is a must!

Pierre

Yes, I checked with them and yes, they said it is possible.

But it currently cannot be done solo by the end user -- engineering must create you a custom config file.

[pisabell]

Hi watchnerd,

Thanks for this info. I agree that it would be much better for the end user to be able to experiment. For example, I had to try several settings in order to find the best output level for my tweeters.

I suppose Devialet will add the end user facility if they receive enough reuests to develop or modify config files for 3-way active setups...

Piere

[pisabell]

Hello all,

My experience with active SBL's using the low/high pass parameters suggested by Waiski roved to be amazingly successful.

As it turns out I am also the owner of a pair of the much larger, 3-way Naim DBL's. I have been using them with the Naim passive crossover, which is also said to be suboptimal. I am now wondnering if it would be a good idea to get a third D200 so that I can drive the DBL's actively. Naim makes available the active SNAXO 3-6 crossover for the DBL, with specs as follows:

- input impedance: 13KOhms
- 300Hz, 3rd order
- 3kHz, 3rd order

In order to emulate that Naim SNAXO, I would need to ask Devialet to provide me with suitable configuration files for the three D200's. But would it be enough to give them the above info about the Naim crossover specs, or would i rather need to give them specs based on the kind of calculation Waiski provided mw with for the SBL's?

Many thanks,

Pierre

[Waiski]

I'm glad to hear that your activation does work. I believe that removing passive crossover improves the sound in most of cases.

Doing 3 way crossover I would start with activating bass. Just remove passive crossover from the bass and do 3rd order active crossover with previously said calculations. Then after that I would try to remove 3rd order high pass from the mid and do also that with Devialet. And the best results you will get to have acoustic measurements and do the fine tuning of delays. All this you can do without help from Devialet. But then the 3 way crossover. You can send the crossover point information to Devialet and see how they are doing it, actually I'm quite sure they are doing it wrong... but would like to see if how they do it.

[pisabell]

Hello all,

Given this success with ative SBL's, I am now thinking about another possibility. I also have a pair of Naim DBL's, which are much larger, 3-way, full-range speakers.

Naim makes an electronic crossover for them called the SNAXO 3-6, and the manual mentions the following specs:

- input impedance: 13KOhms
- crossover frequencies: 300Hz, 3rd order and 3kHz, 3rd order

If I were to get hold of a 3rd D200, would it suffice for me to give Devialet those specs for them to provide me with adequate configuration files? If I undertand correctly, they would be able to produce config files for my three D200's with the crossover frequencies shown above. But what about fine-tunin the output level for the tweeters and the mids? This requires quite a bit of listening with different values. One way, I think, could be to manually edit the config files. I can see for example that the files generated by the configurator for the D200 feeding the tweeters in my active SBL setup contain the following statements:

"_adh_l_max_volume":-7,
"_adh_r_max_volume":-7,

which no doubt corresponds to the -7db I set as output level for my tweeters. Obviously I could manually change this particular value for, say, -6db instead of generating a whole new file with the configurator.

What do you think?

Many thanks,

Pierre

[Soniclife]

I believe there is a check sum that will prevent you manually editing the file. You could test with what you have now.

[Axel]

I believe there is a check sum that will prevent you manually editing the file. You could test with what you have now.

Correct. The configurations are protected by a CRC (Cyclic Redundancy Check), a complex algorithm that generates a code from the config file. Change just one parameter and the CRC will  spot it and prevent it from loading. AFAIK the CRC is unhackable

[thumb5]

I believe there is a check sum that will prevent you manually editing the file. You could test with what you have now.

Correct. The configurations are protected by a CRC (Cyclic Redundancy Check), a complex algorithm that generates a code from the config file. Change just one parameter and the CRC will  spot it and prevent it from loading. AFAIK the CRC is unhackable

There are several common choices of algorithm for 16-bit CRC which IIRC is what's in the config file, so with a little time and experimentation it might not be too hard to work out which of those Devialet are using.  Unless they've invented their own, of course.  The other slight complication in practice is knowing exactly what parts of the file are protected by the CRC - including or excluding white space and line endings, for example.

So I would guess it's probably not unhackable.  Whether the benefits of hacking it - being able to change the config file arbitrarily - are worth the risk of doing some harm, I'm not so sure.