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Quad Subwoofer Plan with the SHD 2 years 9 months ago #40190

  • kishore.yalamanchili
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I just ordered an SHD in order to setup 4 subwoofer outputs via the XLR outputs which will be sourced from one of the analog inputs from my receiver.

My intention is to either use Dirac or manually do distance calibration / delays on all 4 subwoofers and enter this into the SHD.

I also intend to apply some PEQ in some of the drivers in order to counteract the nulls in other drivers (where this is possible) in order to better flatten out the Main Listening Position.

Ultimately I plan to then use the bass management in my receiver to integrate the summed response of the minidsp. I have more of a Sat/Sub setup with crossovers around 110hz for my main speakers, therefore there are issues with "stereo" bass. I intend to send sound from all of my left side speakers to the left front and back subwoofers and the right side speakers to the right front and back subs.

I also intend to do a low pass on the rear subs of around 70-80hz or whichever gets me the best result. I do not want to hear music coming out of the rear subs in a sub/sat setup and only want music to come from the front soundstage.

The concept of "surround sound" bass is practically nonsensical and likely cannot even be perceived in terms of movie effects. I am mostly trying to avoid the presence of 2-channel music coming out of the rear subs and messing with stereo imaging and front soundstage.

In general I have found the subwoofer/satellite style setup very difficult to get right with my horn speakers. There are often significant nulls somewhere between 80hz and 110hz in a typical rectangular house room at the MLP. In a traditional full range front speaker, this is irrelevant since the crossover may be set around 70-80hz but in my setup if I don't do things right, I get a null in a highly noticeable and audible region.

Does all this sound like a reasonable approach?

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Quad Subwoofer Plan with the SHD 2 years 8 months ago #40326

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Welcome to the miniDSP community!
Sounds like a nice application for the SHD.. :-)

All the below is simple to achieve thanks to the internal matrix mixer + output PEQ/Xover/Time alignment.

Keep us updated on how things go!
miniDSP, building a DSP community one board at a time.

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Quad Subwoofer Plan with the SHD 10 months 2 weeks ago #52376

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I have a question for the same usage.

If you use subwoofer preout from the surround receiver and connect it to only one of the analogue inputs on the SHD. Will both channels (left and right) be activated? Or do you have to use two analogue inputs on the SHD?

I assuming routing matrix needs to look like this?

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Quad Subwoofer Plan with the SHD 10 months 2 weeks ago #52380

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I have a question for the same usage.

If you use subwoofer preout from the surround receiver and connect it to only one of the analogue inputs on the SHD. Will both channels (left and right) be activated? Or do you have to use two analogue inputs on the SHD?

I assuming routing matrix needs to look like this?


'Dirac 1' in the signal routing is Input 1 on the back, and 'Dirac 2' is Input 2. If you only have one input signal then just connect this to Input 1 and only worry about the Dirac1 row in routing. What you have currently would be correct for this input. What is in the Dirac 2 row won't make any difference but I'd be inclined to toggle them all to off so that it's clear what is going on.

Note that the version of Dirac Live on the SHD won't sort out the time delays between your subwoofers for you. This you will need to work out for yourself using REW, and then set the appropriate delays in the Outputs tab within the SHD plugin. You might also find an application called Multi-Sub Optimiser helpful.

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Quad Subwoofer Plan with the SHD 10 months 2 weeks ago #52384

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I have a question for the same usage.

If you use subwoofer preout from the surround receiver and connect it to only one of the analogue inputs on the SHD. Will both channels (left and right) be activated? Or do you have to use two analogue inputs on the SHD?

I assuming routing matrix needs to look like this?


'Dirac 1' in the signal routing is Input 1 on the back, and 'Dirac 2' is Input 2. If you only have one input signal then just connect this to Input 1 and only worry about the Dirac1 row in routing. What you have currently would be correct for this input. What is in the Dirac 2 row won't make any difference but I'd be inclined to toggle them all to off so that it's clear what is going on.

Note that the version of Dirac Live on the SHD won't sort out the time delays between your subwoofers for you. This you will need to work out for yourself using REW, and then set the appropriate delays in the Outputs tab within the SHD plugin. You might also find an application called Multi-Sub Optimiser helpful.


Thanks. But I still don't see how it's possible to route both channels to the 4 subwoofers this way. I would like all subwoofers to play both channels. Is that possible when using only one analogue input? I don't see how this works in the routing.

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Quad Subwoofer Plan with the SHD 10 months 2 weeks ago #52395

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Thanks. But I still don't see how it's possible to route both channels to the 4 subwoofers this way.


How many independent subwoofer outputs does your AVR have? If it's only one then you have no 'both channels' to do anything with. Just one.

For AV applications there is usually one LFE channel (which may include a mix from other channels two) that is sent to all subwoofers that are in use. The value of a miniDSP to you is then to be able to adjust the relative timing of each sub to give the most even total frequency response, in combination with EQ applied.

For music there is the option to send a left channel signal to a left subwoofer, and a right channel signal to a right subwoofer, but I would advise that it is better to send a combined left+right channel signal to both subwoofers anyway (which is what I do).

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Quad Subwoofer Plan with the SHD 10 months 2 weeks ago #52400

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Thanks. But I still don't see how it's possible to route both channels to the 4 subwoofers this way.


How many independent subwoofer outputs does your AVR have? If it's only one then you have no 'both channels' to do anything with. Just one.

For AV applications there is usually one LFE channel (which may include a mix from other channels two) that is sent to all subwoofers that are in use. The value of a miniDSP to you is then to be able to adjust the relative timing of each sub to give the most even total frequency response, in combination with EQ applied.

For music there is the option to send a left channel signal to a left subwoofer, and a right channel signal to a right subwoofer, but I would advise that it is better to send a combined left+right channel signal to both subwoofers anyway (which is what I do).

Only one subwoofer output, but that's not the issue here. This is about how and whether the single input on the SHD is mixed to two channels. There's nothing in the matrix routing that shows that's possible as far I can see. There should be something showing how to mix the input signal to left and right out.

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Quad Subwoofer Plan with the SHD 10 months 2 weeks ago #52401

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Only one subwoofer output, but that's not the issue here. This is about how and whether the single input on the SHD is mixed to two channels. There's nothing in the matrix routing that shows that's possible as far I can see. There should be something showing how to mix the input signal to left and right out.


Stop thinking about two channels :) .

You need to use the SHD as a one input, four output device. 'Left' and 'Right' don't have any relevance to what you are trying to do. You have a single (mono) input, and you'll want all four outputs to be reproducing a version of this (subject to time delays and EQ).

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