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Old 4th September 2010, 01:15 AM   #1
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Default Stereo Image

I finally got my minidsp/digi/amp combo hooked up with a decent power supply
And its playing music but it seems to not be in stereo its configured as two channel and is being driven by a qa550 wave player.
Everything adjusts OK but if I mute an input slider I get music from both speakers I put a CCR song on where Fogerty's voice is only on one channel and its again coming equally out of both speakers all the matrix mixer controls are left on full.
I double checked jumpers and speaker connections but I am at a loss as to why there is such poor stereo image. before I dust off the oscilloscope maybe the Minidsp Guys can chime in with some input
Thanks and woof
Beardawg
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Old 4th September 2010, 02:58 AM   #2
minidsp is offline minidsp  Hong Kong
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Hello,

From your post, I'm guessing that you're using miniDSP kit with a Mixer plug-in.. Am I right?

I'm quite certain that the problem you're hearing is related to the configuration in the matrix mixer. You mention that all knobs in the matrix mixer are at full, while they shouldn't be if you want a stereo field.

I would recommend you read p9 of the miniDSP user manual to understand how a matrix mixer works. Here is a short version:
- Each knob represents the mixing level at a crosspoint. i.e. Input to output. Rows are inputs, columns are outputs.
- If all knobs are at full, it means that left is routed to OUT1,2,3,4 AND right is also routed to 1,2,3,4.
- If you want a stereo field, Left signal (e.g. in1) should only be routed to OUT1&2. Meaning 1st row, only 1st and 2nd knob should be at full while 3&4th knob should be at -60dB
- Same applies to row 2 (input 2), but this time the opposite. Knob 1&2 should be at -60dB to make sure Right channel doesn't go to left speaker out 1&2. While knob 3&4 should be at 0dB.

Something like this:

0 0 -60 -60
-60 -60 0 0

Hoping this makes sense, you'll see that everything will sound at it should! :-)
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Old 4th September 2010, 04:22 PM   #3
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Hi Minidsp
Thanks for the quick response. So when in doubt read the instructions.
Adjusting the matrix mixer solved everything. Another question if I may.
I have Rev.b board and the Miniamp is configured to 12 db gain playing from
a qa550 wave player via optical cable to Minidigi the input meters average -40 db (Half way) with the sliders on 0 the speakers sound mid loud level with no strain or distortion (Fostex fe206esr 98db/w advertised) I've had these speakers louder on an analogue system I am thinking I should have rev A board and set the mini amp to to -3 db gain configuration.what do you think?
also
Here's a suggestion for future software revisions a link button for the input sliders so they both go up together
Thanks for a great product
BD
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Old 6th September 2010, 01:58 AM   #4
minidsp is offline minidsp  Hong Kong
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Hello,

Glad to hear that your system is up and running as it should :-)
With regards to the level question, miniDSP revA&B is only different on the analog input path (ADC sensitivity). Because you're using miniDIGI as an input source, it doesn't matter which miniDSP version you are using. -40dB is a bit low for a signal, and indeed you could get more "juice" out of this rig if you had more input signal from the SPDIF source. In our tests with squeezebox, Audio precision, Pioneer DVD players, we reached levels about 15 to 20dB more... Maybe try another SPDIF source?

Quick questions: Are you using miniAMP in BTL or SE(4ch mode)?

As for your idea of linking, it's a great idea which we'll consider for future versions.

Hope this info helps,
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Old 6th September 2010, 04:08 AM   #5
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Hi Minidsp
I am using btl mode (two channel)
I get similar loudness with optical input or analog input via Minidsp
from a CD player I haven't tried spdif yet the qa 550 wave player has I2s output
off the circuit board itself but with a digital data streams the loudness is in the bits themselves no?
Thanks
BD
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Old 7th September 2010, 04:04 PM   #6
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Hi Minidsp

I was able to take care of the level issue very simply.
I edited my wave files in Audacity and normalized them for 0.0db
and all is good nice full level with the sliders all the way not a hint of distortion
I would recommend this product to anyone.
Five stars
Thanks
BD
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Old 8th September 2010, 01:16 AM   #7
minidsp is offline minidsp  Hong Kong
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Glad to hear that you're all set and have your system up and running as it should!

Thanks for your kind comments and Enjoy!
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