LX-mini Crossover Article

[avdesignguru]

Thank you very much for your advice. I have purchased lxmini in store and waiting to receive it.

I'm not sure how the 4343A input terminal and switching works. If switching to the biamp mode gives direct access to the 10" mid range voice coil as well as to the 15" woofer voice coil, then 12dB/oct symmetrical would probably be appropriate. Linkwitz-Riley alignment is usually recommended because it gives flat power response through the pass band. The reason I ask about direct connection to the 10" voice coil is that my ADS L980 speakers, when switched to biamp mode, give direct access to the 12" woofer but still keep the passive HP filter connection to the 2" mid range - probably to avoid potential driver damage. So I run 12dB/oct active to the mid/highs which adds to the 12dB/oct passive to give 24dB/oct. Then I run 24dB/oct active to the woofer to match the response.

 

[nomores23]

when swithching to biamp mode in 4343, LF direct access to the 15" woofer and HF goes directly to a passive crossover which leads to MF 10", HF horn and UHF. Base on it's original design, the active crossover is 12db/oct and cut at 290 hz for LF, they use only one cut for LF, I don't see they talk about cut for HF, so that is my concern. At this moment, I use an active crossover dbx 223xs which provide one cut at 290 hz with 24db/oct for LF, and the result is good. I hope lxmini could improve the result due to dbx 223xs is just a commercial product and they have to reduce the quality to match the competition pricing. By the way, could you explain how to run the woofer in 24db/oct? by changing the pole or anythingelse?

I'm not sure how the 4343A input terminal and switching works. If switching to the biamp mode gives direct access to the 10" mid range voice coil as well as to the 15" woofer voice coil, then 12dB/oct symmetrical would probably be appropriate. Linkwitz-Riley alignment is usually recommended because it gives flat power response through the pass band. The reason I ask about direct connection to the 10" voice coil is that my ADS L980 speakers, when switched to biamp mode, give direct access to the 12" woofer but still keep the passive HP filter connection to the 2" mid range - probably to avoid potential driver damage. So I run 12dB/oct active to the mid/highs which adds to the 12dB/oct passive to give 24dB/oct. Then I run 24dB/oct active to the woofer to match the response.

 

[avdesignguru]

when swithching to biamp mode in 4343, LF direct access to the 15" woofer and HF goes directly to a passive crossover which leads to MF 10", HF horn and UHF. Base on it's original design, the active crossover is 12db/oct and cut at 290 hz for LF, they use only one cut for LF, I don't see they talk about cut for HF, so that is my concern. At this moment, I use an active crossover dbx 223xs which provide one cut at 290 hz with 24db/oct for LF, and the result is good. I hope lxmini could improve the result due to dbx 223xs is just a commercial product and they have to reduce the quality to match the competition pricing. By the way, could you explain how to run the woofer in 24db/oct? by changing the pole or anythingelse?

It sounds like you need the same config as my ADS: 24dB/oct LP and 12dB/oct HP. If you can confirm that there is a cap feeding the 10" with a coil in parallel with the 10" voice coil, that would make the existing passive HP to the 10" 12dB/oct. Since I had already worked this out for my ADS at 500Hz, I have attached the schematic for your 300Hz requirement. If you want to download LTspice (it's free) I have included the simulation file as well.
Good luck!

 

[Nelson Pass]

I have a nice board that does this, 6-24 dB/oct. We are considering
putting a version of it in the store.

 

[cubicincher]

I am thrilled!

Hello Mr. Pass,


please give us this beautiful toy!


I see multiple stages/slopes, buffers, .....
pots for adjustability...
perhaps dip-switches+resistors for adjustable/switchable frequencies?


I am dreaming


Greets Dirk

 

[Nelson Pass]

Ha. You guys are so easy to please......

 

[R-K Rønningstad]

Papa is teasing the boyz!

 

[Nelson Pass]

Always.

 

[pixelpusher]

Yes! This is what I have been waiting for.

 

[Nelson Pass]

I probably will need to revise it before release, but it can happen in a
month or so.

 

[RemcoB]

Ooh yes! I've been waiting for this!

 

[cubicincher]

Fantastic!

These are fantastic news! Thanks Mr. Pass that you will offer this 'babe' to us fanatics!
You are generous as always And now - patience - the master is working

Greets

Dirk

 

[laverda]

Great news..

 

[WalterW]

Yes!

 

[avdesignguru]

message to nomores23

Since private messages do not appear to allow attachments, I am posting them here.

LXmini values for 12dB/oct HP and 12dB/oct LP at 260Hz

 

[woofertester]

I have a nice board that does this, 6-24 dB/oct. We are considering
putting a version of it in the store.

Nice. It will sell and be appreciated. I would buy one for sure, maybe two.

 

[Berd]

Looking forward to it and waiting patiently. Well, truth be told, only patiently because I am neck deep in another project. Preoccupation done well enough is a reasonable approximation of patience

 

[chrisb]

That last sentence would make for a good signature line or bumper sticker.

 

[timfournier]

I have just powered up and checked the voltage values as per the build guide.

They are all correct except the R1 - 4 and R31 and 32. Instead of showing ~12 V they show 0V. Where should i start looking for the problem?

Tim

 

[timfournier]

Please ignore last post: i read the instructions properly and measured against an earth they were all 12V.