Possible Mini dsp issue? - AVS Forum
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post #1 of 3 Old 08-06-2012, 12:33 PM - Thread Starter
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So I built some test cabinets for my line array project using 12 Dayton RS150t and 4 BG neo 8pdr per side. Running the woofer line full range with my Yamaha RX-V3000 (around 100 watts per channel) the array got very loud at around -30 to -25 on the volume dial. I then hooked up the mini dsp to crossover the woofers and tweeters and now I have to turn the dial to -15 to -10 to get it somewhat but not really loud. And have the woofer line hooked up to a toshiba amp rated at 100 watts with meters and at that volume the meters peak at 0.3 watts, not even a full watt. I plan on buying a pair of amps rated at 200 watts but don't want to put out the cash if I'll only see a 3db rise as it still won't be very loud.

I have the unbalanced .9v mini dsp. Would it help adjusting the input voltage to the .3 or whatever. The power supply I'm using for the minidsp I'd 5v at like 550mA. Could that be the problem?

Dan
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post #2 of 3 Old 08-13-2012, 02:58 PM
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bump. i see nobody has replied. have you resolved this one?

sounds like you are not getting enough output voltage from your receiver.

if the noise floor remains low enough, can't you just amplify the signal in your mini?

i doubt the power supply for the mini has anything to do with your matter.

Listen. It's All Good.
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post #3 of 3 Old 08-13-2012, 03:46 PM
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I'm pretty sure its not the power supply. I power mine off the 5V that comes through the USB cable and it works fine for me. It sounds like you might need voltage gain but you also might have misconfigured the crossover. So first bypass the crossover terms and any filters one by one to see if that restores normal volume (being careful not to send too much low frequency tothe tweeters in the process).

If the crossover and filters test OK that way perhaps you need more gain. You can get that by configuring a PEQ term as a pure gain stage. It looks like you can't do that without going into advanced mode.

I'm pretty sure its not the power supply. I power mine off the 5V that comes through the USB cable and it works fine for me. It sounds like you might need voltage gain and you can get that from the MiniDSP if you use advanced BIQUAD programming mode.

Here is an set of biquad coefficients for 6 db gain:
biquad1,
b0=1.995262314968880,
b1=0.000000000000000,
b2=0.000000000000000,
a1=0.000000000000000,
a2=0.000000000000000,

Here is a set for 12 db gain
biquad2,
b0=3.981071705534970,
b1=0.000000000000000,
b2=0.000000000000000,
a1=0.000000000000000,
a2=0.000000000000000,

to use them open the MiniDSP tool to the Parametric EQ window and select advanced mode. then when the window opens up showing default parameter values just cut and paste one of the above in. You can hack to get the gain you want. I know that is a little bit terse so let me know if you have trouble. This may not work but it is worth a try.


Jack
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