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  • Signal Processing Question: Paging Mr. Soundman

    I was planning to use two mini DSPs to process the audio from my CarPC. One would process the left channel of sub, mid bass, mid, and tweet and the other would process the right. I have two 4ch amps so the whole system would be active.
    However, I am hearing to many complaints about noise and even the manufacturer states the mini DSP was intended for the home and not car audio system. Its a shame too because for the price I could not find a piece of equipment that did all the mini DSP did but I feel no price is worth adding noise into my system.
    So now I have a line on a PPI FRX-456 crossover. This will allow me to keep my four way active system but does not provide any EQ or TA like the mini DSP. How hard would it be to do these with my Win7 PC? How transparent are these plug-ins to RR and other plug-ins like .netBluetooth phone and RR voice?
    I'm thinking I just need EQ and TA. I have no rear channel so I don't need fade control and I think I can control volume through the PC somehow. Am I overlooking anything?

    Mal
    Vehicle: [100%] 1995 C 1500 ECLB
    Gear: [90%]
    Build: [80%] PC & Chassis, Worklog

  • #2
    Originally posted by 4ofakind View Post
    I was planning to use two mini DSPs to process the audio from my CarPC. One would process the left channel of sub, mid bass, mid, and tweet and the other would process the right. I have two 4ch amps so the whole system would be active.
    However, I am hearing to many complaints about noise and even the manufacturer states the mini DSP was intended for the home and not car audio system. Its a shame too because for the price I could not find a piece of equipment that did all the mini DSP did but I feel no price is worth adding noise into my system.
    So now I have a line on a PPI FRX-456 crossover. This will allow me to keep my four way active system but does not provide any EQ or TA like the mini DSP. How hard would it be to do these with my Win7 PC? How transparent are these plug-ins to RR and other plug-ins like .netBluetooth phone and RR voice?
    I'm thinking I just need EQ and TA. I have no rear channel so I don't need fade control and I think I can control volume through the PC somehow. Am I overlooking anything?

    Mal
    you can do all of taht through vst plugins and a multichan card and drop the ppi

    4 way active? what's your setup?
    New System in progress:
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    My Car Pc Install
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    • #3
      You can see my PC in my sig. I can't fit a sound card in my set up and my on board sound just has the three jacks, one of which is "mic in".
      My amps are MB Quart DSC480s. Two PPI SQ8s and a set of PPI Power Class Three way seperates. I did not go specifically go looking for another PPI piece, it just happened to work out that way. I was looking at Audio Control for an active crossover but I just wasn't completely happy with what I would have to do to make them work.

      Mal
      Vehicle: [100%] 1995 C 1500 ECLB
      Gear: [90%]
      Build: [80%] PC & Chassis, Worklog

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      • #4
        ya know, there are others that know this stuff better then me

        it looks like your hardware should handle audio processing fine. but you'll need a audio card. my esi-gigaport will do 8 channels, but ASIO doesn't work very well, so i needed to use a the standard WDM driver. also, it's got a very low audio output, so a preamp is required..

        being that i do all the processing on the pc, i support this method. the downside is that if the pc goes down, so does the audio system... so i keep a 3-way active x-over for a 3.5mm audio input.

        the cheapest way to get into audio processing is to use Console. it is a basic vst host, for less then $100, and it needs to be approached as such.. after comparing console and audio mulch, i really prefer audio mulch. it is almost 4 times the price--$180, but it is much more stable, and less cpu intensive, and includes some nice little plugins..

        if you haven't seen it before, i typically recommend checking kvraudio.com for plugins. they have a huge resource for all sorts of plugins.
        My OLD 2001 Mitsubishi Eclipse GT:
        "The Project That Never Ended, until it did"


        next project? subaru brz
        carpc undecided

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        • #5
          If you decide to go with a standalone crossover, I recently received a Coustic XM7 in trade. After putting a new molex power plug on it and making 3 power cables for it, I would probably be looking at $150 for it if interested. These are pretty rare 5 way crossovers. Still does not have TA or EQ however, but if you really feel you need EQ that can be done in software. 2 channel TA can also be achieved in you use winamp + vst bridge + load a VST plugin chainer + then adding EQ and TA plugins (only gives you two channel control). I have not tried the allocator winamp plugin, but perhaps that will work as well to achieve multichannel active control.

          The miniDSP noise problem is due to poor/cheap/easy grounding design. The signal ground shares the same ground as the power input which creates a ground loop issue. Some people solved this by purchasing expensive transformers (Jensen..not the car audio brand) to isolate the ground signal coming out of the minidsp from going into the amp. There was suppsoed to be an add-on balanced board that might resolve it, but no idea if that happened or if anyone tried it if that product was available.
          Last edited by durwood; 03-22-2011, 08:30 AM.
          System always under construction


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          • #6
            Originally posted by durwood View Post
            If you decide to go with a standalone crossover, I recently received a Coustic XM7 in trade. After putting a new molex power plug on it and making 3 power cables for it, I would probably be looking at $150 for it if interested. These are pretty rare 5 way crossovers. Still does not have TA or EQ however, but if you really feel you need EQ that can be done in software. 2 channel TA can also be achieved in you use winamp + vst bridge + load a VST plugin chainer + then adding EQ and TA plugins (only gives you two channel control). I have not tried the allocator winamp plugin, but perhaps that will work as well to achieve multichannel active control.

            The miniDSP noise problem is due to poor/cheap/easy grounding design. The signal ground shares the same ground as the power input which creates a ground loop issue. Some people solved this by purchasing expensive transformers (Jensen..not the car audio brand) to isolate the ground signal coming out of the minidsp from going into the amp. There was suppsoed to be an add-on balanced board that might resolve it, but no idea if that happened or if anyone tried it if that product was available.
            Hey Durwood thanks for the offer. Do you have a pic of the crossover? I am definitely going w/ a standalone xover because I am not able to nor do I want to change my on board sound card to get more than 2 channels out.
            Tell me more about the winamp + vst bridge + load a VST plugin chainer. I am a noob on this. I thought Console or Audio mulch replaced Winamp as the audio player? And if they still work w/ Winamp they should integrate seamlessly w/ RR and its various plugins right?

            Mal
            Vehicle: [100%] 1995 C 1500 ECLB
            Gear: [90%]
            Build: [80%] PC & Chassis, Worklog

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            • #7
              Originally posted by 4ofakind
              I thought Console or Audio mulch replaced Winamp as the audio player? And if they still work w/ Winamp they should integrate seamlessly w/ RR and its various plugins right?
              right.

              Console, and audio mulch are separate programs from winamp-- winamp is a audio player, console/AM are audio manipulation. in most car audio uses of the programs, console/AM doesn't create any sounds(though, in a pro audio/DJ environment, i have seen some pretty crazy audio mixes using AM).

              the easiest way to explain it is that, in most installs, they intercept the windows sound after it has been created--weather it is a winamp noise, or other program--, and passes that audio through whatever plugins you have installed.

              but either solution--AM, or winamp+vst bridge-- should not affect your use within rr.

              the plugin that durwood is talking about is a add-on for winamp. the vst bridge+vst plugin chainer does almost what AM does-- minus the audio routing. to further describe this-- these plugins would allow audio manipulation, but would not allow audio to be sent to specific soundcard outputs--you are stuck with left channel, and right channel audio.

              the "vst bridge" is available in the winamp plugin area.

              the "vst plugin chainer" is available from sites like kvraudio.com here is a example:
              http://www.kvraudio.com/get/2497.html
              My OLD 2001 Mitsubishi Eclipse GT:
              "The Project That Never Ended, until it did"


              next project? subaru brz
              carpc undecided

              Comment


              • #8
                Here is the manual for the crossover. It really is one of the coolest and one of only two 5 Way analog crossovers. I almost hate to get rid of it.
                www.coustic.com/support/pdfs/XM-7.PDF

                I will get pictures up in a bit.

                Here is how you do 2 channel plugins, keep in mind foobar also has a "vst wrapper" to do the exact same thing. Both players are supported by Road runner.

                1)Download and install VST bridge. For foobar it's called something else like vst wrapper.
                http://www.winamp.com/plugin/vst-winamp-bridge/146317

                2) Download other vst's like Voxengo Time Delay or Electric-Q (Electric-EQ was created by same person as the VST bridge for winamp. Put into one central folder (they are just .dll files)
                http://www.savioursofsoul.de/Christi...s/eqs-filters/

                3) Search for and download a VST plugin effect chainer. This will act like an "audio rack" where you can load mutliple VST's and they feed into each other usually only 2 channels worth. I think I just found one that can do channel routing too. way
                http://www.xlutop.com/html/chainer.html

                4) Open winamp/foobar and go to "preferences". Goto the the DSP section and select the vst bridge/wrapper.

                5) Click "configure" and then browse to where the effect chainer is. THis will load in the effect chainer.

                6) In the effect chainer, you can load a VST into each "slot". (Sorry this is generic, but you will have to do some work on your own and not all are the same),

                So when RR plays music through foobar/winamp it sends the audio stream through vst bridge to the effect chainer which then runs it through your VST plugin effects (EQ, time delay, etc) and finally out of winamp to your soundcard/windows mixer.

                Clear as mud?
                Last edited by durwood; 03-22-2011, 09:27 PM.
                System always under construction


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                • #9
                  Actually that is very clear from both you and Soundman thanks.
                  My only question now Durwood is that it looks like I will not need a VST Host in the setup you described right? Does the eq plugin have a GUI to change setting? Im sure it does but had to ask the stupid question anyway.

                  Mal
                  Vehicle: [100%] 1995 C 1500 ECLB
                  Gear: [90%]
                  Build: [80%] PC & Chassis, Worklog

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                  • #10

                    Yep, they have nice colorful GUI interfaces. Not exactly designed for touchscreen use so you will have to use a mouse. The vst bridge/wrapper becomes the host, only a 2 channel host inside the software player.

                    No pressure on the XM7, the PPI FRX456 was a nice crossover as well and one that used on my original carpc build many years ago. I liked the detented adjustment knobs on that one. THe PPI was also smaller than this thing.

                    Here are pics (click on thumbs for bigger pics), it's missing one plastic knob:







                    ---------- Post added at 09:24 PM ---------- Previous post was at 09:22 PM ----------

                    System always under construction


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                    • #11
                      My Amp Rack

                      That Coustic is pretty big. I am not sure where I will put it. I think I will build a shelf behind my amp rack, under the rear seat for it and my power distribution block. I would prefer it all be on the rack, but alas I don't think I have enough room.

                      Mal
                      Attached Files
                      Vehicle: [100%] 1995 C 1500 ECLB
                      Gear: [90%]
                      Build: [80%] PC & Chassis, Worklog

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                      • #12
                        Yeah, unfortunately it is as big as some amplifiers at 8-1/16" x 11-1/8" x 2-1/8". That is part of the reason I really pursued using the carpc for all processing. One less box to fit. You are even more strapped from room in a pickup. Any room on the sides of the rear seats? How about up front in the center console area?
                        System always under construction


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                        • #13
                          Hey Durwood or Soundman I have a question.
                          Does your method of Signal Processing make your CarPC sound less like desktop speakers?
                          For example: I recently had the chance to sit in a friends car who just installed a Pioneer deck with an amp and a set of Focal three ways. It sounded great; like a concert hall. I then went to my truck and with my PC playing MP3s through Win Media Player; no WinAmp yet or any processing and it sounded like tiny desktop speakers in a can. Will the VST plugins improve this or is it just the nature of the beast?

                          Mal
                          Vehicle: [100%] 1995 C 1500 ECLB
                          Gear: [90%]
                          Build: [80%] PC & Chassis, Worklog

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                          • #14
                            FIY: I know it’s a bit late but way back when I decided to purchase a Mini-DSP I tried a number of searches of this forum and found nothing (later found a bug in search). I am running a mini DSP and its absolutely dead quite, totally noise free. I really have to wonder just how people wire their systems. I initially ran analogue to DSP but now run optical from PC to the DSP, in both cases it was/is and continues to be completely noise free.
                            Palm sized ainol MiniPC, 8" Transreflective PRO, Win10, Reverse camera, Dual 10HZ GPS RX's for Speed Display & Sat Nav, FM-DAB & Phone Modules, iDrive interface. T-Screen HVAC control, custom microcontrollers, microcode and FE.

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                            • #15
                              My setup is noise free as well (First Try WOOT!) But I expected it to sound more like a car stereo than a PC (If that makes any sense). Im thinking it has alot to do with the quality of MP3s compared to CD recordings. And then the DAC in the Pioneer deck compared to my on board sound card.
                              I was in no way expecting my PPIs to sound like his Focals but Im a little disappointed.

                              Mal
                              Last edited by 4ofakind; 01-12-2012, 06:40 PM.
                              Vehicle: [100%] 1995 C 1500 ECLB
                              Gear: [90%]
                              Build: [80%] PC & Chassis, Worklog

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