Active Linkwitz Riley crossover/DSP

[BtwoG]

Hello!

About 20 years ago, I built what was a pretty state of the art set of speakers. I used active crossovers boards (XM1) from Marchand to implement a 4th order LR crossover between the woofer and midrange. I also used Elliot Sound Products' Linkwitz Transform (bass boost) board to equalize the woofer flat to around 20 Hz. Long story short, the crossover has stopped working, and I started thinking there must be something newer and better out there.

My search led me to this wonderful audio forum, but I must admit that I've spent 4 or 5 hours searching around and dont have the answer I'm looking for.

I would like a processor that does an 8th order LR crossover and has the ability to also implement the Linkwitz Transform. I'd like the flexibility to change the cutoff frequencies without replacing modules. I can make do with just the crossover (no Linkwitz transform) if needed but would like both if possible. I'm not really looking at going down the DIY path again (soldering boards together) I see lots of great suggestions here, like Behringer, miniDSP, DEQX, RCF, dbx, even old Rane gear. I would like something that doesnt have a steep learning curve. It would be great if these units had canned filters I could use. I've been out of the audio space for so long, I just dont know where to start and the learning curve is difficult to gleen from the discussions here.

Thanks!

 

[staticV3]

Hi @BtwoG! Welcome to ASR.

miniDSP have an extensive library of well-written guides on everything that is to know about using their products, so that's probably the best place to start.

Here the link: https://www.minidsp.com/applications

 

[ppataki]

Hello!

About 20 years ago, I built what was a pretty state of the art set of speakers. I used active crossovers boards (XM1) from Marchand to implement a 4th order LR crossover between the woofer and midrange. I also used Elliot Sound Products' Linkwitz Transform (bass boost) board to equalize the woofer flat to around 20 Hz. Long story short, the crossover has stopped working, and I started thinking there must be something newer and better out there.

My search led me to this wonderful audio forum, but I must admit that I've spent 4 or 5 hours searching around and dont have the answer I'm looking for.

I would like a processor that does an 8th order LR crossover and has the ability to also implement the Linkwitz Transform. I'd like the flexibility to change the cutoff frequencies without replacing modules. I can make do with just the crossover (no Linkwitz transform) if needed but would like both if possible. I'm not really looking at going down the DIY path again (soldering boards together) I see lots of great suggestions here, like Behringer, miniDSP, DEQX, RCF, dbx, even old Rane gear. I would like something that doesnt have a steep learning curve. It would be great if these units had canned filters I could use. I've been out of the audio space for so long, I just dont know where to start and the learning curve is difficult to gleen from the discussions here.

Thanks!

Simplest way to make this happen is to use a PC as your source and then you can easily use state-of-the-art DSP software there

I personally use Jriver with a combination of various VST plugins
I currently have a 2-way coax system with 2 individual subs + rear channels for movies (so 8 channels total), I use linear phase crossovers (24dB/oct LR), delay, room correction with Dirac Live, tube emulation, etc etc ....all with the PC, no need for any dedicated hardware

 

[kemmler3D]

Another option if you want to go full active is the Hypex Fusion plate amps, which have DSP built in.

 

[BtwoG]

Thanks everyone for the quick responses. I see both LR crossover and Linkwitz transforms in the miniDSP applications. Looks like a great product.

Looks like the Flex is the one to get? I dont need streaming.

 

[sam_adams]

I used active crossovers boards (XM1) from Marchand .. . . the crossover has stopped working,

Those XM1 boards were so simple that probably the only thing wrong with them is a bad El-cap, opamp, solder joint, or simply oxidation on one of the leads of the removable components. Have you tried contacting the company (Email: [email protected]) to see if they have any suggestions to fix the issue?

 

[Wolf11Man]

If you are in Europe, consider this one https://www.thomann.de/de/the_t.racks_dsp_4x4_mini_pro.htm
They have three versions of the "mini": XLR, Jack plug and one including 4 amps. Also there are many other DSP's, all will do what you want.

 

[Keith_W]

You first need to decide whether you want minimum-phase IIR or linear-phase FIR. Every product recommended in this thread falls into one of these two categories.

Minimum-phase IIR is replicates the functionality of analog crossover components with the same penalty of phase rotation with amplitude and is thus more difficult to design. MiniDSP is mixed phase, meaning it has IIR and FIR, but with a limited number of FIR taps.

OTOH linphase FIR / constant-delay filters deliberately add a delay to the impulse so that amplitude can be manipulated independently of phase. This means that ALL symmetrical crossover orders and Q's will sum perfectly. You can also correct the minimum-phase behaviour of individual drivers and make them linear phase. The downside is that a lot of taps are needed, thus more computing power - especially if you want a lot of channels. MiniDSP does not have enough CPU grunt, so you would be looking at an ARM chip (Raspberry Pi) as a minimum, or a PC.

Whether there are audible differences in avoiding driver phase distortion by going linear phase FIR instead of minimum phase is somewhat controversial. Toole and Linkwitz do not think so. But JJ does. This white paper explores the benefits of going linear phase.

 

[DonH56]

If you want a basic analog crossover, the dbx223 works well, and is inexpensive.

https://www.sweetwater.com/store/detail/223XS--dbx-223xs?_queryID=188ffd812df982bde1a18caafe2f3d6b&_index=production_products

 

[dualazmak]

Simplest way to make this happen is to use a PC as your source and then you can easily use state-of-the-art DSP software there

Agree with you!
In my case, I use DSP software "EKIO" as system-wide one-stop DSP center within an audio(-visual) dedicating Windows 11 Pro PC together with VB Audio MATRIX (as system-wide ASIO VASIO VAIO routing center) and JRiver MC (as system-wide audio player and library manager); feeding DSP-ed digital audio signals into 8-channel DAC OKTO DAC8PRO.

For your, i.e. OP @BtwoG's, possible interest and reference, you would please find the details of my latest system setup in my post here #931 on my project thread.
Here in this post, let me share only four diagrams (out of total 34 diagrams/photos) from that post under the below spoiler cover.

Spoiler

 

[dualazmak]

You may also find "understandable-at-a-glance" system diagrams and photos of many other ASR friends' audio rigs on this thread "Let's share diagrams (and photos) of our total physical audio system and the whole signal path, with a few words and/or links".

 

[DWPress]

The miniDSP gear is probably going to be the easiest to implement and you only need to have it hooked up to a computer long enough to do the initial filter set up and then it works on it's own. The Flex is great but they have other offerings that'll do what you want too, decide based on the actual features you need.

If you do have a computer as part of your signal chain then there are many more options as suggested above but you will need at least a 4 channel DAC or sound card. A measurement microphone, stand, and a familiarization with the app REW will get you even further into the rabbit hole.