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3 way digital crossover [message #85827] Tue, 13 August 2013 23:25 Go to next message
actualsizeaudio is currently offline  actualsizeaudio
Messages: 7
Registered: August 2013
Location: Canton, CT
Junior Member
OK, so the time has come to use my Mio console as a 3 way digital crossover for a Tannoy Dual concentric speaker building project I've undertaken.

I've got a few ideas on how to do it, but I'd love to hear from the MH experts on how they would do it.

I figured I would make a new 5.1 listening Bus. I would then make a graph with 3 Stereo EQs. One for the sub, mid, and high. Then I would have a 5.1 output that routed to the 6 analog outputs I would need.

Am I a luddite? Is there a better way to do this, where I can get steeper slope filters?

Thanks in advance.

-Mike


1Lio8 and 2ULN8s make for happy studio
Re: 3 way digital crossover [message #85829 is a reply to message #85827] Wed, 14 August 2013 08:32 Go to previous messageGo to next message
actualsizeaudio is currently offline  actualsizeaudio
Messages: 7
Registered: August 2013
Location: Canton, CT
Junior Member
OK, after watching the tutorial on how to use bass management within the Mio Console I see that I was pretty close. It states to use the band pass block in the graph, instead of the EQ. Is there a reason why this will be more suitable than using HP filters within the Mio EQ?

Also, I have one worry about the setup. In order to switch over to my "main" set of speakers, which these will be, I will have to pick both a different speaker output AND a different listening buss. That worries me for one reason: If I pick the "Main" speaker source and NOT the special 5.1 listen bus that will have the DSP setup, I will send full range sound to all 6 outputs of my 3 way system. The drivers are vintage Tannoy HPD drivers, and I'm very afraid that this will damage the high driver. I feel like that is too much of a risk, and that in the heat of things I might pick that source with the non DSP audio thus blowing the tweeter.

Thoughts on a work around?


1Lio8 and 2ULN8s make for happy studio
Re: 3 way digital crossover [message #85830 is a reply to message #85829] Wed, 14 August 2013 12:43 Go to previous messageGo to next message
Allen is currently offline  Allen
Messages: 156
Registered: July 2011
Senior Member
Administrator
If you use a 7.1 bus instead of a 5.1 bus, you can pass 2 channels of full range audio and don't need two source busses. In the following example, I've created a 7.1 bus and inserted a graph:

http://metric-halo.com/imagehosting/7dot1_Graph.jpg

- Inputs 1&2 are connected directly to Outputs 7&8; this is your stereo output for headphones or full-range speakers
- Inputs 1&2 also go to the first bandsplit, which is set to 5 kHz; this is your highpass crossover and sets the upper frequency limit of the mid driver. The High outputs go into another bandsplit, which is only inserted for time alignment between the high and mid/low outputs. The second split is set to 10 Hz and the High outputs go to Output 1&2 of the graph.
- The Low outputs of split 1 feed split 3, which sets the lower limit of the midrange and sets the lowpass. The High outputs (which are the mid in this application) go to Output 3&4, and the Low outputs go to Output 5&6.

The next step is to configure the Monitor output paths:

http://metric-halo.com/imagehosting/7dot1_MonitorOuts.jpg

I have a Cans path, which takes the stereo full range signal on channels 7 and 8 of the 7.1 bus and routes them to the Cans outs, and a Full Range path that routes those channels to Analog outs 7/8. Finally, the 3 Way path routes channels 1-6 to Analog outs 1-6 without passing the full range signal.

With this setup, you can switch between your fullrange and three-way outputs without switching the monitor controller source.


Metric Halo
www.mhlabs.com
727-725-9555
Re: 3 way digital crossover [message #85831 is a reply to message #85830] Wed, 14 August 2013 21:53 Go to previous messageGo to next message
actualsizeaudio is currently offline  actualsizeaudio
Messages: 7
Registered: August 2013
Location: Canton, CT
Junior Member
Very nice indeed. Thank you.

I'm curious about the band split. What type of filter is it? I assume it is a steep IIR filter of some sort?


1Lio8 and 2ULN8s make for happy studio
Re: 3 way digital crossover [message #85834 is a reply to message #85831] Fri, 16 August 2013 09:37 Go to previous messageGo to next message
Allen is currently offline  Allen
Messages: 156
Registered: July 2011
Senior Member
Administrator
It's a 24dB/octave Linkwitz-Riley filter.

Metric Halo
www.mhlabs.com
727-725-9555
Re: 3 way digital crossover [message #86224 is a reply to message #85834] Tue, 04 August 2015 17:24 Go to previous message
chmedly is currently offline  chmedly
Messages: 2
Registered: August 2015
Junior Member
So, it's strange but I've never actually built a crossover on the +dsp. I'm astounded to find that there are very few options for basic high and low pass filters. It seems that the low pass in the MIOEQ plug-in is a 2nd order (which I had to measure to determine). And the bandsplit is a fixed 4th order linkywinky. How can I get a simple 1st order filter? I must be missing something simple?
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