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TOPIC: Re: My dsp project build.

My dsp project build. 9 years 10 months ago #850

  • petegt
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I think its overdue that I post my project up as I have recieved allot of help from this forum.


mourduant short MS 5.20 with retrofitted soft dome tweeters(much easier on the ear I find but maybe not as crisp)


Bill Fitzmaurice Tall Autotuba 16" wide(front loaded folded horn with horn loading down to 45hz) loaded with a JBL GTO 804 driver.

I have 2 identical TAT's but only use one for normal listening. I use them both for house partys with the morduant shorts just about keeping up when processed.


I purchased a the dsp because there is a big time allignment issue between the horn and the mid tops.
The dsp will also be used for equilisation but the crude rta i have achieved with TrueRTA and an uncalibrated mic showed the morduants to be quite flat in response.

The box:

LEFT phono: dsp input and dsp bypass (for subwoofer amp)
Left knob: minidsp volume control.
Right phonos: dsp pre amp outs with gain adjustment knobs.

USB socket, fuse and Nuetric Powercon socket. Still going to add a power led and would like to add a dsp led if possible (to flash etc with the led on dsp board)

The insides:

This shows the pre amps and the psu i used. The Preamps are based on the ne5532 op amp and are quite low noise but i do get some static noise which i would like to get rid off. These pre amps can provide 2-3V output but the input(output of dsp) has to be limited to 0.5V which is why I have used the external volume control pot.

My psu:

I bought this as a complete pcb without the heatsink becuse the current draw is so low.
# Maximum input voltage of 35 volts
# Output current up to 1A (external heatsinking may be required check with datasheet for details)
# Output voltage: 12V
# LED indicator on output side
# Reverse polarity connection protection on Input side
# Thermal overload protection
# Short circuit protection
# Output transition SOA protection

I used a psu so that the dsp is protected and ready to be used in a car.


So far I am only using the dsp for bandpass filters for the morduant shorts (120hz 30db butterworth - 20000 48db linkwitz) and time time delay of 5.64ms per chanel.

The subwoofer amp has its own low pass at 80hz 12db butterworth and 35hz highpass.

This is just a rough set up, lots of experimenting to do.
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Re: My dsp project build. 9 years 10 months ago #852

  • devteam
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Very nicely integrated and documented project Pete!

You guys must have some fun house parties with those massive subs! :-)

great stuff.... Keep us updated with the progress!
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