[jagman]

Hi,

I have a MiniDSP 2x4 Balanced that I'm attempting to set up.

My HT equipment:
1. Denon AVR 4311
2. Crown XLS802D pro amp -> four FiCar Audio IB3 18 subs in an array at the front of the HT
3. Samson S700 pro amp -> four Infinity 1262 subs for nearfield duty (just behind my second row of seats)
4. Buttkicker amp -> four Mini-LFE transducers under the first row of seats
5. MiniDSP 2x4 Balance with 2x4 Advanced plugin

Here's my proposed setup...

Denon 4311 receiver (two sub outputs) ->

sub out 1 -> MiniDSP input 1
sub out 2 -> MiniDSP input 2

MiniDSP output 1 -> channel 1 Crown XLS802
MiniDSP output 2 -> channel 2 Crown XLS802
MiniDSP output 3 -> channel 1 Samson S700 (the amp is set to dual mono so the one input is sent to both channels)
MiniDSP output 4 -> Butkicker amp for Buttkicker MiniLFE transducers

Variables:
The Denon is obviously a consumer level device that has RCA outputs.
The Crown and Samson amps are pro equipment that use XLR inputs.
The Buttkicker amp is consumer level so it also uses RCA inputs.
I want the IB subs to be EQed by Audyssey so I have Sub Out 1 -> MiniDSP Input 1 -> MiniDSP Output 1&2
I want the NF subs and Buttkickers not EQed by Audyssey so I have Sub Out 2 -> MiniDSP Input 2 -> MiniDSP Output 3&4

Since I'm dealing with several devices and the gain structures of them are different, I'm asking for the best way to set them up.

My thoughts...

1. The gain input on the MiniDSP 2x4 Balanced should be set to the lower level since the Denon is just a consumer level device.
2. The gain output on the MiniDSP 2x4 Balanced should be set to the higher level since the Crown and Samson amps are pro amps and perform best with higher gain input (I think).
3. The Buttkicker amp may not fare well with the output gain of the MiniDSP set to the higher level??? I'm not sure. The reason why I want the Buttkicker fed by the MiniDSP is twofold. The first is to set delays appropriately. The second is to use a high pass filter to keep the transducers from bottoming out (which is unfortunately easy to do with the ones I have).

Please advise on how to set up the gain structure appropriately of the MiniDSP 2x4 Balanced in this scenario. Of course I welcome any advice on changing my setup to better use the equipment I have. Thanks in advance!

 

[Wayne A. Pflughaupt]

I’ll start by saying that I don’t have a miniDSP and have never used one.

That said, the much ballyhooed differences between consumer vs. pro signal levels is mostly nonsense. Your Samson amp only requires a .8V signal to be driven to its maximum output. The Crown requires only 1.75V for the same. By contrast, most modern AVRs will output way more than that, except perhaps for the lowest-end products of a given model line.

Just set the miniDSP for its maximum capacity for both inputs and outputs, which I think is 2V? Its only job is to pass the AVR’s signal through without adding distortion. So the more headroom, the better. The AVR probably puts out more than 2V max, and the amps can certainly accept way more than that. So, the limiting device will probably be the miniDSP, if there are issues.

You might want to review my epic piece on gain structure, which you can find in my signature. You’ll probably be most interested in Part 7 and Part 9.

Regards,
Wayne

 

[jagman]

Thank you! Given that the selctable gains are:

IN: 4Vrms / 1.8Vrms (jumper–selectable)
OUT: 2Vrms / 4Vrms (jumper-selectable)

Just to clarify, which ones would you choose?



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[Wayne A. Pflughaupt]

In 4 and out 4.

Regards,
Wayne

 

[jagman]

In 4 and out 4.

Regards,
Wayne

Great. Just to confirm setting the MiniDSP 2x4 Balanced to 4 in despite the receiver feeding it being consumer grade with RCA outs is ok? That goes against my instinct but I'll defer to your expertise .

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[Wayne A. Pflughaupt]

Not sure I get the question? The 4311 can only deliver an unbalanced signal to the mini via it’s RCA jacks. What other option is there?

Regards,
Wayne

 

[jagman]

Not sure I get the question? The 4311 can only deliver an unbalanced signal to the mini via it’s RCA jacks. What other option is there?

Regards,
Wayne

I probably just don't understand everything as well as I should. Here's how I've hooked it up...

I'm using the following XLR/Phoenix adapters to assist connected the receiver and amps...

Hosa PHX-206FBULK 6-Inch Adaptor PHX3F to XLR3F

www.amazon.com/dp/B003D83OWC/ref=cm_sw_r_cp_apa_v4yRAbA5B9T4V

The cables between the Denon AVR and the Hosa XLR/Phoenix adapters at the MiniDSP input are these...

www.monoprice.com/product?p_id=4777

I'm using the same adapters for the outputs from the MiniDSP. Between the adapters and the pro amps are these...

The following adapter...

Hosa GXX-144 XLR3M to XLR3M Gender Changer

www.amazon.com/dp/B000068O4J/ref=cm_sw_r_cp_apa_dfzRAbB6PBJNC

And the following cables...

www.monoprice.com/product?p_id=4754

Lastly, between the MiniDSP and the Buttkicker amp I'm using the same XLR/Phoenix adapters and the the following cable...

www.monoprice.com/product?p_id=4777

Unfortunately I'm not getting any sound out of my subs (only the IB subs run by the Crown amp hooked up to MiniDSP Outputs 1&2 are plugged in). I'm quite sure the MiniDSP is set up correctly. I took the cover off to check the gains are the way I want them (the input and output gains were left as the were from the factory at 4 in and 4 out as you suggested). Since the cover was off I plugged it in (not touching things of course) and the internal LED is blinking blue. With the 2x4 Advanced plug in on and the receiver playing a bluray disk the input gain is circa -29dB while the output gain is circa -67dB gain with the slider on the left at zero. If I move the slider down then it decreases the output gain even further. The fact that the output gain is so low relative to the input sensitivity inherently seems problematic but I don't know enough to say for sure.

I also question whether the XLR/Phoenix adapters may be a problem since I don't think they match the wiring diagram in the MiniDSP manual. I also don't know what's going on inside the XLR to RCA cables to convert from one type of connection to the other so that's another variable.

I've also posted all this on the MiniDSP forum but they are not as responsive as you.

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[Wayne A. Pflughaupt]

Sorry, since I don’t have the miniDSP, I have no point of reference for the gain settings. Seems to me that everything that's adjustable should be set for unity (0 dB), so that the signal level going in is the same as what's going out. There's no good reason to adjust the miniDSP's internal gain settings from unity, unless you've applied such tremendous amounts of EQ that the output signal is drastically lower or higher than what came it. That really shouldn't be, and if it is that's a whole 'nother topic of discussion.

When you take the miniDSP out of the loop and connect your cables straight to each other (minus the Phoenix of course), do you get a signal to the amp?

Speaking of, that’s a really convoluted connection/adapter scheme you got going there! Since you already have all the parts, I’d just cut the XLR connector off of this cable and connect the Phoenix directly to it. Same thing with the XLR-to-XLR cable.

Check my guide to DIY cable-making in my signature for directions on how to strip and prep the cable for the Phoenix. Same process as for soldering on a connector, only you don’t need to solder for a Phoenix.

An added advantage is that you’ll be able to ditch the female connector from the Monoprice XLR cable, which is a piece of junk scheduled for failure at some point in the future – as explained in this post.

Regards,
Wayne

 

[jagman]

Sorry, since I don’t have the miniDSP, I have no point of reference for the gain settings. Seems to me that everything that's adjustable should be set for unity (0 dB), so that the signal level going in is the same as what's going out. There's no good reason to adjust the miniDSP's internal gain settings from unity, unless you've applied such tremendous amounts of EQ that the output signal is drastically lower or higher than what came it. That really shouldn't be, and if it is that's a whole 'nother topic of discussion.

When you take the miniDSP out of the loop and connect your cables straight to each other (minus the Phoenix of course), do you get a signal to the amp?

Speaking of, that’s a really convoluted connection/adapter scheme you got going there! Since you already have all the parts, I’d just cut the XLR connector off of this cable and connect the Phoenix directly to it. Same thing with the XLR-to-XLR cable.

Check my guide to DIY cable-making in my signature for directions on how to strip and prep the cable for the Phoenix. Same process as for soldering on a connector, only you don’t need to solder for a Phoenix.

An added advantage is that you’ll be able to ditch the female connector from the Monoprice XLR cable, which is a piece of junk scheduled for failure at some point in the future – as explained in this post.

Regards,
Wayne

Ok Wayne. You're the man! I nixed the adapters. I snipped off the end of the cables going to the MiniDSP from the receiver and the amps. I removed the plugs from the XLR/Phoenix adapters that go into the Phoenix recepticals on the MiniDSP and inserted the bare wire from the original cables into those plugs according to the manual. I then plugged them into the MiniDSP. Bam. No hum and solid bass . That's it for tonight but soon I'll break out my mic and REW and really tame this beast! Thanks for your help and patience. I really appreciate it.

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[Wayne A. Pflughaupt]

Glad to hear the good news, jagman! Kudos to you, too – if you hadn’t taken the time to detail your connections, we would have never figured this thing out. Connection problems are not something we typically assume.

Regards,
Wayne