TOPIC:

Hey Guys,

I have been talking to you in e-mail and wanted to put this up here for those who come looking like me.

I am hoping to use a Single miniDSP + miniDIGI combined with 2 miniAMP to provide 4 channels of 20watts @ 8 ohms output for use in a 2.1 system. Obviously only 3 of these channels would be used, but that is beside the point.

I am planning to use relatively efficient Line Array designs for my L/R Mains + a horn loaded 8" sub. These are BFM TLAH + TableTuba designs. The mains will be approx 96dB SPL ) and the TT from 30-80Hz will be 105+ db SPL

My main requirement is to maintain a fully digital signal path. Input will be coming from S/PDIF input from computers/TV/CD players etc. I am using this system in a relatively small listening space and 20watts of headroom is HEAPS.

So is it possible to use a single DSP + digi to route a 2.1 signal across 2 miniamps, into 3 bridged channels?

While doing all this is it possible to apply a HPF to the sub output at 30Hz? From what I have seen this should be possible but I just want to confirm. Thanks!

This is my main query. I have 2 more though

2) What kind of power supply would be recommended for a setup like this? Would a single 100watt supply into a miniAMP power the whole stack? Or would I put 50watts to 1 miniAMP and 50watts to another to power it and the rest of the stack? I don't know a lot about electronics I am just getting into it all for the first time.

3) Would it be possible to use 1 miniDSP, 1 miniDIGI & 2miniAMP and do 2x 2 way cross overs and a summed sub output channel? It would be interesting to make the whole system active, would allow me to fine tune my line arrays very well. But I would still be aiming for a 2.1 system. Obviously the 2 way cross over section would be running at 10watts @ 4 ohms ea, but this would not be an issue. I can easily change the driver count on the line arrays to wire for 4ohm impedance.

Thank-you for time, I know my questions are fairly all over the place, but I hope to make my first decent audio system a good one.

Mitchell

While not specifically an answer to your question (can I do this with two mini-amps), I did want to share my own experience. I just bought one Mini-DSP and one Mini-Amp and the 2.1 module to drive two BFD SLA's for mains and a single Tuba18 for the sub. She gets plenty loud for my living room. I did have to turn the mains down a little to balance the sub. I'm driving the SLA's with 10 watts each and the sub with 20 watts. I did put an HPF at 40Hz to my T18 (LPF at 80 Hz).

The bass can get plenty loud (for me) with this much (little?) power. If I truly need it louder, I'll drive the mains with 20 watts each channel from the mini-amp and connect my 100W sub amp to the T18.

I don't see needing that anytime soon.

-Brian

Thanks for the info! Have you gone fully digital? Like with the miniDIGI?

Just hoping the dev team gets back to me soon

I didn't go with the mini-digi (yet). While I do have two digital sources, a music player and a blueray player, I don't care about full surround sound and haven't figured out yet if I were to plug my BR player in digitally, would I HAVE to deal with the full 5.1 sound or can I get just a 2 channel digital out for my system.

I hope that makes sense.

-Brian

Yeah it would depend if the miniDSP could decode, but generally S/PDIF doesn't pass through the top quality codecs anyway not enough bandwidth. Your Blu-Ray Player may just down mix.

I wish I could get a purpose built mini receiver for 3.1 sound. Thats all I want. A receiver that takes 2x optical, 1 HDMI in and 1 Out. With 4 channels of 50-100watts with one set to the LFE with a selectable cross over and a parametric EQ with a good 10 bands. Don't want no auto setup, or anything else fancy just decode and give me 3.1 And also strip tv 2 channel output and mix to 3.1. Really a simple little box. I could get an older 5.1 receiver but none power the sub or are all digital amps.

So I stick with 2.1 ...

@MitchH311,

In answer to your questions:

While doing all this is it possible to apply a HPF to the sub output at 30Hz? From what I have seen this should be possible but I just want to confirm

Yes, each output is LPF + HPF. Please have a look at the datasheet of the plug-in. Thanks.

2) What kind of power supply would be recommended for a setup like this? Would a single 100watt supply into a miniAMP power the whole stack? Or would I put 50watts to 1 miniAMP and 50watts to another to power it and the rest of the stack?

Either ways will work fine... Easier might be 2 power supplies of 50W each.

3) Would it be possible to use 1 miniDSP, 1 miniDIGI & 2miniAMP and do 2x 2 way cross overs and a summed sub output channel? It would be interesting to make the whole system active, would allow me to fine tune my line arrays very well. But I would still be aiming for a 2.1 system. Obviously the 2 way cross over section would be running at 10watts @ 4 ohms ea, but this would not be an issue. I can easily change the driver count on the line arrays to wire for 4ohm impedance.

Not sure what you mean by 2x2way crossover. See the 2.1 audio DSP flow diagram. The input gets split by the crossover for Low and High in stereo. Users would typically use the miniDSP in this configuration to build a stereo Sub + Satellites configurations. Easiest might be for you to clarify your inputs, your outputs and their respective processing .e.g.
Input #1: Left signal
Input #2: Right signal
Output #1: Low left signal..

etc

Hope this info helps,

DevTeam

Input# S/PDIF L/R

Hoping to output:

Right
: High 4kHz - 20kHz 10watts
: Low 80Hz - 4kHz 10 watts

Left
: High 4kHz - 20kHz 10watts
: Low 80Hz - 4kHz 10 watts

Sub:
Mono 30Hz - 80Hz 20 watts

so 2 Mini Amp 1 with all SE channels 1 with BTE channel all run from one miniDSP and miniDIGI

So active 2 way highs + mono sub output.

Mitch,

If you count your outputs, you do realize that it's 5 outputs. A miniDSP can only output/process a maximum of 4 outputs. In other words, this configuration wouldn't work on 1 x miniDSP.

You need to rethink a bit your system to run on 2 x miniDSP kits and therefore split the stack (couldn't stack all together so many boards). How about thinking about it as a 2 x systems:
- analog input for sub, going to a dedicated miniDSP kit for Sub (Mono 30Hz - 80Hz 20 watts)
- Digital input for L/R using miniDIGI + miniDSP + 2 x miniAMP

Have a think about it,

DevTeam
- Or have

Hi Thanks for the reply.

I was just asking whether I could go active in this manner purely as a point of interest. 20watts per channel at 4 ohm's is perfectly fine for me. I'll stick with 1 dsp and 2 amps.

All the best.
Mitch