TOPIC:

OK, I need some help please. I'm planning on building a 2.1 system using your PWR-ICE125 plate amps. The satellites will be 2 way loudspeakers, and there will be one sub, so I'm going to use 3 plate amps. I also want to use the DSP and DAC in each of the plate amps, so I know I need to get a digital signal to all of them. If I have multiple digital sources, what products that you offer would I use to build the box that takes these digital inputs and produces the proper digital outputs for the plate amps? I would need a master volume control as well. All of the DSP and crossover work is going to be performed by the plate amps, so I don't see where you offer a product that can do what I need to do, do you? I can build equipment no problem. I just need to know what to build. For example, I see that the plate amps want an AES-EBU input. How do I provide that if I have normal digital consumer type sources? (I see that you suggest an adapter to in your application guide: "If using digital input, a normal S/PDIF (RCA/coax) digital source can be connected with an RCA to XLR adapter cable." - what connection diagram is needed for this adapter cable? (there are a couple of possibilities)) Basically, as I see it, I need to build some kind of digital switch box with a volume control where I can select each digital source to the desired output, is that right? Any help is appreciated. Thanks.

I would look at the nanoDIGI 2x8. It has 1 spdif input and up to 8 outputs. The datasheet states that you can use a remote as a volume control.
www.minidsp.com/images/documents/Product...noDIGI%202x8%20K.pdf

As for the XLR digital input on the plate amp, page 10 of the manual gives a pin diagram on what connectors to use. Under "digital unbalanced connection" it states to connect pin 2 to an RCA shield and pin one goes to positive. Pin 3 is not used.
www.minidsp.com/images/documents/PWR-ICE...%20Manual%20v1.0.pdf

OK, great, thanks. The nanoDIGI seems to be much more than I need since all of the DSP work is done by the plate amps for each loudspeaker. I think it's a great idea to have individual cable runs to each plate amp from one box like this, and the volume control is great too. Is the DSP needed for digital volume control?

I can get my cable guy to make the cables up, thanks. I didn't realize that the pinouts were in the manual.

Also, which DAC is being used in this plate amp? I can't find that info.

As for my control box, do I really need another DSP chip? Can I use the VOL-FP plus something else (DIGI-FP?) instead of the nanoDIGI 2x8? I just need to switch between a few digital inputs to one digital output, and have a master volume control. Can I use a miniDIGI with the VOL-FP?

Yeah, it looks like I need DDRC-22D to do what I need. Now I just need $900.... sigh.

dirkwright wrote:

Is the DSP needed for digital volume control?

Yes. The DSP is required.

dirkwright wrote:

Also, which DAC is being used in this plate amp? I can't find that info.

Look at page 12 of the manual. There is a block diagram that lists the DAC as "Analog Devices SigmaDSP" ADAU1445
Here's a link to the datasheet for that chip: www.analog.com/media/en/technical-docume...AU1442_1445_1446.pdf

[edit] Oops... I just realized you were asking for the DAC and I listed the DSP. Sorry.

dirkwright wrote:

As for my control box, do I really need another DSP chip? Can I use the VOL-FP plus something else (DIGI-FP?) instead of the nanoDIGI 2x8? I just need to switch between a few digital inputs to one digital output, and have a master volume control. Can I use a miniDIGI with the VOL-FP?

The VOL_FP and DIGI-FP are just input/output and control devices. They have to interface with a DSP. The miniDIGI will only switch between sources if you physically move jumpers on the board. If you want, you can build a switching device to switch the jumpers. The manual gives instructions on how to do that. It states that you must use break before make switches. It would be manual though...

dirkwright wrote:

Yeah, it looks like I need DDRC-22D to do what I need. Now I just need $900.... sigh.

Actually you could buy the OpenDRC-DI and do the same thing. It's only $325. They are the exact same box. The only difference is that the DDRC-22D comes with a license for DIRAC live, which you won't need since you are only using this box as a switch and a volume control.

How many devices are you wanting to switch? Are they all digital? Spdif coax or optical? Any analog devices?

Yeah, I've got a little bit of mission creep here. I realized it would be better to have something like miniDIGI 2x8 to EQ the room instead of building a passive digital switch box with volume control. Can you give me a brief idea of what's the difference between using the miniDIGI 2x8 for room EQ vs. something like the OpenDRC-DI or DDRC-22D for room EQ? What's the difference between what you can use with the OpenDRC ( I assume "open" in this case means open platform for third party software?) and the DIRAC live? I'm sure I can look it up eventually if I have the time but if you can give me something brief that would be super, thanks. I've been reading through several manuals and other information sheets about this equipment and I find it very confusing.

sly wrote:

How many devices are you wanting to switch? Are they all digital? Spdif coax or optical? Any analog devices?

Well, let's see, I have a CD transport with several choices of digital outputs, and I have a DAT with digital out as well. I expect to add some kind of streaming device with digital output, so that's at least 3. The DAT has a pro level AES output as well as coax, the transport has both spdif coax and optical, but who knows what the streaming device will have. Then there are other possibilities in the future as well. For this system, it's going to be strictly digital. Thanks for your help.

dirkwright wrote:

Can you give me a brief idea of what's the difference between using the miniDIGI 2x8 for room EQ vs. something like the OpenDRC-DI or DDRC-22D for room EQ? What's the difference between what you can use with the OpenDRC ( I assume "open" in this case means open platform for third party software?) and the DIRAC live? I'm sure I can look it up eventually if I have the time but if you can give me something brief that would be super, thanks. I've been reading through several manuals and other information sheets about this equipment and I find it very confusing.

I'm new to MiniDSP too. There is a bit of a learning curve if you are not used to DIY audio systems. But the more you read, the more you realize what you can now do that you could never do before. I like the openDRC and the DIRAC live platforms because they both use the miniSHARC chip. This chip allows you to do FIR filtering. MiniDSP has several articles on what this means. If you are new to it, it means that the miniSHARC has the ability to not just correct EQ (amplitude response) but also phase response. If you know what you are doing, you can phase correct (linear phase) your drivers no matter what kind of crossover they have. The DIRAC live platform is more of an automatic setup. It comes with proprietary algorithms and test sequences to perform these corrections for you. It's kind of like having a software "wizard" to guide you through the setup process. However, IMO, the openDRC can do the same thing. They are the same hardware. The difference is that with the openDRC, you have to learn how to do the measurements yourself and you have to build the FIR filters yourself using third party software. There are freeware programs out there that can do this such as rePhase and REW... but you will need to take the time to learn how these programs work and through trial and error, create the filters needed to correct your system

MiniDSP has several articles on using both REW and rePhase. www.minidsp.com/applications/digital-cro.../opendrc-as-fir-tool

The nanoDIGI 2x8 uses a different platform. It won't do FIR filtering but it will do practically everything else. It has 5 bands of parametric EQ for both of the inputs and then for each of the 8 outputs, it has 5 more bands. It can do full crossover functions, time alignment (delay), gain and even dynamic range compression. It's also more affordable.

dirkwright wrote:

Well, let's see, I have a CD transport with several choices of digital outputs, and I have a DAT with digital out as well. I expect to add some kind of streaming device with digital output, so that's at least 3. The DAT has a pro level AES output as well as coax, the transport has both spdif coax and optical, but who knows what the streaming device will have. Then there are other possibilities in the future as well. For this system, it's going to be strictly digital. Thanks for your help.

It sounds like you might be better off with a home theater receiver to act as a switch for all your devices and then use an openDRC-DI or a DDRC-22D for room correction and volume control.

The home theater receiver can handle the input of all your devices plus give you the room to grow as you add more. Then you can use an SPDIF output of the receiver to connect to a miniSHARC based device. This can perform FIR filtering for phase correction and room correction. It will also have a volume control for your digital source. Then you can use the plate amps to EQ each driver "flat" and to equal out the volume levels between them. Sounds like a good setup.

If you want to use one remote control for everything, I would look over the owner's manual for either the openDRC or the DDRC. They list what brands of remotes will work with these processors. Then I would look for a home theater receiver that follows one of these brands. Then you can use the remote to switch between your devices on the receiver, and the same remote to control the volume with the openDRC/DDRC processor. Place the processor physically close to your receiver so both devices can see the remote at the same time and it would work seamlessly.

I looked closer at the ICE125 amp and is has an XLR digital output. It looks like you can daisy chain your amps together, digital out to digital in, with XLR cables. The openDRC-DI and the DDRC-22D both have XLR digital outputs as well. So you won't need any custom cables; just regular XLR cables.

Yes, thanks. My plan today is to use the OpenDRC-DI with 3 of the PWR-ICE plate amps, all daisy chained together via AES balanced cable.

I'm not new to audio, just to these kinds of all digital setups with DSP chips. I'm used to the old analog way of doing things. I'm really impressed with what these new digital systems can do though so I'm sold on them already. Doing an all digital system really reduces the number of boxes and cables as well, which makes for a neater appearance in the living room (where it's important). Thanks again for your help!

sly wrote:

The openDRC-DI and the DDRC-22D both have XLR digital outputs as well. So you won't need any custom cables; just regular XLR cables.

The one caution (dirkwright seems to know this based on his reply) is to watch the impedance of the cable. You'll want 110ohm (aka AES/EBU or DMX lighting) cables. Mike and pro audio analog XLR cables can be all over the map.

DS21 wrote:

The one caution (dirkwright seems to know this based on his reply) is to watch the impedance of the cable. You'll want 110ohm (aka AES/EBU or DMX lighting) cables. Mike and pro audio analog XLR cables can be all over the map.

Actually, I didn't realize that! Thanks. I'm so up to my eyeballs in trying to figure out DRC and other things that I completely forgot about needing special cables. Yes, I will need AES/EBU cable for this system, not ordinary analog XLR cable.

dirkwright wrote:

DS21 wrote:

The one caution (dirkwright seems to know this based on his reply) is to watch the impedance of the cable. You'll want 110ohm (aka AES/EBU or DMX lighting) cables. Mike and pro audio analog XLR cables can be all over the map.

Actually, I didn't realize that! Thanks. I'm so up to my eyeballs in trying to figure out DRC and other things that I completely forgot about needing special cables. Yes, I will need AES/EBU cable for this system, not ordinary analog XLR cable.

Monoprice sells them cheaply. They list them as DMX lighting cables, but that's the same thing (110ohm XLR connector).