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3-way 12 years 6 months ago #3

  • cfelliot
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Do you have wiring for 3-way crossover. I assume this would require 2 boards.

Can 2 invocations of the software setup be run concurrently for each board?

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Re:3-way 12 years 6 months ago #4

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Hello,

We currently don't have a 3 way crossover but we're already working on a 4 way crossover plug-in as we speak! :-) We're hoping to have it ready by next week but we'll see how the schedule goes.
As for running 2 boards concurrently, it's unfortunately currently not possible with the way we control the boards(would require unique identifier). It will maybe happen one day though, if we get the request enough to justify redesigning the software/firmware.

Stay tuned,

Dev Team.
miniDSP, building a DSP community one board at a time.

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Re:3-way 12 years 6 months ago #5

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I assume the 4-way means low-pass, high-pass and 2-Band-passes using only one input and a board for left and right?

This would be even better allowing high,mid, low and sub!

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Re:3-way 12 years 6 months ago #6

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Yes indeed that's correct. The 4 way configuration will be 1 Low pass, 2 band pass (with asymmetrical controls) and 1 high pass. Stay tuned for release early next week.
miniDSP, building a DSP community one board at a time.

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Re:3-way 12 years 6 months ago #9

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A few more questions:

Do the crossover filters model the phase shifts inherent in the filter type or just the slope? If so, it might be nice to have a filter that is just the slope. Phase shift is what we are trying to avoid in an electronic crossover.

Can the MiniDSP be supplied with a DC voltage and allow a USB connection concurrently? I’m thinking of operating mode vs. setup mode.

A possible add-on: SPDIF -> I2S board.

Regards,
Chuck

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Re:3-way 12 years 6 months ago #10

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Chuck,

In answer to your questions:

Our plug-in currently plots the amplitude curve of each filter (i.e. low pass and high pass curve). Plotting the equivalent phase response and overall combined effect of both filters would certainly be a great add on. We already plan to work on it for future versions of the plug-ins but as with any product development, it's best to introduce features over time.

Does it mean that you should wait till we have a new plug-in? Not really. Our plan is to issue "free upgrades" once you buy the modules. All our members will receive a download link once a plug-in version gets upgraded so that everybody gets to enjoy the latest features.

As for the DC power option, yes you can have USB & DC voltage together connected. Our thought was the same as yours. You wouldn't want to have to switch DC power supply when you just want to control the device.

SPDIF -> I2S board is on already on its way. :-) Stay tuned

Feel free to ask any other questions you may have,

Dev Team
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Re:3-way 12 years 6 months ago #29

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Hello,
I've got few questions about minidsp.

Is it possible to set bandpass filters?

When will you release 4-way version of the kit?

Is it necessarily to use volume potentiometer? Can I use only volume knob in my car head unit. (stereo cinch connection from headunit pre out)

Is it possible to control two boards (4-way use) with only one volume potentiometer?

Will it be possible to get 4-way analog signal from only one SPDIF "in"? (with two boards of course)

Will it be possible to add other filter slopes e.g. 6dB/oct or 48dB/oct?

Is it possible to change maximum input level to 4V because some of the car headunits have 4V preouts

How to connect the board in car? I understand its +12V, GND, and what about REM which would turn on minidsp when the audio system starts?

Regards,
Tom

P.S. Sorry for my english ;)

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Re:3-way 12 years 6 months ago #30

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Hello Tom,

A good post full of very good questions so let me try to answer them all. Unfortunately, our team is taking few days off between Xmas & New Year so I'll have to wait to hear back from our engineers on a couple of points.

Is it possible to set bandpass filters?

Yes, It will be possible.

When will you release 4-way version of the kit?

Good question! :-) We've been swamped with prototyping the new boards (making great progress) and manufacturing in bigger quantity and unfortunately the plug-in got delayed a bit. Next week, when the team is back together, we'll work hard on getting that new version out. Announcement to follow.

Is it necessarily to use volume potentiometer? Can I use only volume knob in my car head unit. (stereo cinch connection from headunit pre out)

No, it's not necessary but you still have to be carefull about what we call "Gain structure". By default, without a potentiometer, the volume will be at maximum. I'll be writting a much longer FAQ next week about how to correctly setup gain with a minidsp. (or any piece of audio equipment as a matter of fact!)

Is it possible to control two boards (4-way use) with only one volume potentiometer?

Very interesting idea which we've never tried to be honnest. I don't see any reason on why it wouldn't work knowing the circuity but I'll have to test it out first to see if it indeed does work.

Will it be possible to get 4-way analog signal from only one SPDIF "in"? (with two boards of course)

The SPDIF in splitting to 2 boards has been discussed among us and there is still a bit of work (Hardware + firmware) to make it happen. We do have a plan of action, we just need to make it work. Making the kit very flexible along with stacked boards isn't always a piece of cake but we'll work it out. The short answer to your question is yes, we'll make it happen but sa

Will it be possible to add other filter slopes e.g. 6dB/oct or 48dB/oct?

Yes but we don;'t think that we'll get it out in the first version. Firmware development works best when you start small and enhance features. Starting out with a big wish list of features could make the firmware unstable as we wouldn't be able to test 100% everything. This being said, with the free un-limited ugprades of a plug-in, you'll certainly get that feature to you very soon!

Is it possible to change maximum input level to 4V because some of the car headunits have 4V preouts

I can't answer that question right now, but will check with our engineering team next week. If my memory serves right, the answer is no. 2Vrms would be the maximum the input could withstand. That doesn't mean that you wouldn't be able to "pad" the input to fit the input stage limitations. More about it next week.

How to connect the board in car? I understand its +12V, GND, and what about REM which would turn on minidsp when the audio system starts?

We don't have the equivalent of an REM input but a miniDSP kit is a very low power device. I'll confirm next week on the power consumption as I don't have it on hand but I remember it to be just few mA under 5V. In an effort to keep the cost low, we didn't include that feature, maybe in the future will we design a board more geared toward Car Audio (with such features) if we get enough interest from the community?

Hope all this answer most of your questions and will reply to the rest next week.

Tony
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Re:3-way 12 years 6 months ago #31

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SPDIF:

Are you planning to add SPDIF to the miniDSP or as an add-on board? It would seem that an add-on would make more sense.

Will this be a conversion from SPDIF to I2S? If so it seems a simple matter to decode the L/R and direct it to different 2 or 4 way miniDSPs via the bulkhead connectors.

It regard to the dual volume control, this looks like a division of a reference voltage to the gain input. Unless there is a loading issue, I see no reason the the reference couldn't drive two boards. With a little more elaborate external circuit you should be able to have a balance pot too!

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Re:3-way 12 years 6 months ago #32

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Chuck,

Indeed the SPDIF will be as an addon since we want it to be completed with a Sample Rate Converter (SRC) so that users don't have to worry about the sample rate of the input signal.

The I2S will indeed split to two boards, there are still however some little things to be figured out on how the firmware will handle selecting the correct input. Currently the idea is to follow the same concept as we have for input selection in our current plug-in. I.e. selecting L or selecting R input from the I2S feed. (Radio button selection)

Balance control is indeed a neat idea! Let me look into that closer when I go back to work next week and find out the external circuity that would be required to make it work well.

More to follow next week and keep sending ideas!
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Re:3-way 12 years 5 months ago #36

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For those of you interesting,

New kid on the block is out! Check out our 4 way crossover plug-in now available in our webstore. Datasheet is also available in the download section of our website.

What you should know?
- We included 4 band pass for greater flexibility
- 6dB and 48dB are yet to come but were already budgeted in the DSP code. UI and control are just to be developed so instead of waiting longer, we decided to release them in the next revision. With our Free-upgrade policy, all users will benefits of new features as we keep enhancing plug-ins.

Have fun!
miniDSP, building a DSP community one board at a time.

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