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The new MiniDSP 2x4HD has made all my skills obsolete. How about yours?

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  • #31
    I've got a small army of MiniDSPs. Started using them about 3-4 years ago. I use them in the car and the house. The revelation came to me from being in the commercial A/V industry, and working with various DSPs from Symetrix, BSS, QSC, BiAmp... Started looking for more affordable devices to play with, and found MiniDSP. MiniDSP certainly has its limitations, like closed architecture, somewhat low(but useable) output levels(much better on the balanced versions of their products). What it has going for it is affordability, easy to use GUI, good sound quality, convenience...

    I completely understand the art involved in getting a passive crossover designed and built right, and why some would be against the active route due to the need of more amplifier channels. One still needs to understand pretty much the same principals of passive when setting up an active system. The drivers and the enclosure stay the same, so driver roll-offs, response, distortion, impedance...they still matter, as does woofer enclosure size, alignment, tuning, baffle size... Having said that, the convenience of getting a system up and running with a baseline can't be beat. From there, the ability to tweak, tweak, tweak to your heart's content is a matter of a few mouse clicks. Admittedly, for the tweakers among us(me included) it can be a never ending game at times.

    Driver efficiency matching is no longer a part of the equation. Smaller wattage amplifiers can be used since there are no passive components in the circuit to suck up power. Depending on DSP, Butterworth, Linkwitz/Riley, Bessel...all of them can be tried with 1st to 8th order roll-offs. Parametric EQ to tame peaks. High/low shelf EQs, to tame a rising response of a driver(like using a waveguide to boost low end of a dome tweeter). Also, having the ability to switch between up to 4 filter presets on the fly, for comparison, is just so darn handy. Another example, in the car...preset 1 for that majority of the music I listen to, 2 for bass shy music, 3 for talk radio where too much bass is really annoying, and 4 is the jamout preset, for those times when I just want to turn it up and keep all crossover points in a very driver safe region, but still sound good.

    My home theater L/C/R and subs are all DIY DSPed speaker systems. My bedroom system is DSPed. My kitchen boom box consists of a DSP, a 4x100 amp board and BT/aux in, my cars have DSPed systems...yes, I am a fan.

    I haven't yet tried the HD/FIR filter MiniDSP, and likely won't, as I'm moving to commercial units with open architecture, better gain stages, and the ability of control via IP/serial and, of course, FIR.

    There's really a lot of good to DSP, especially with the affordability of devices like MiniDSP, and "cheap" watts available these days. Someone once made the argument that they don't want to have a rack full of amps and a slew of cables between them and the speaker...and they don't have to. Multi-channel amps that are the same size as a 2 channel(or much smaller if one goes the amp board route), multi-conductor speaker cable can be bought, or made, 4 or 8 pole Speakons for a single connection at the speaker...

    Edit: I haven't yet had an issue with DSP latency, not in the fixed install commercial field, or in my home use. The only instances where this could potentially arise, in my experience, is in large auditoriums where rear fills aren't aligned with the mains, but that's a long distance/room/acoustical issue, not an internal DSP processing latency issue. In these situations, the mains get delayed to sync with the rears, which works to various degrees, depending on the room itself, and the room/system integration. Even then, if video projection is part of the system, I haven't yet experienced any visible/audible sync issues. I imagine some of this latency talk comes from those with experience with home recording on a computer and using a hardware interface for inputs/outputs. In those situations, yes, latency is a much bigger contender, and needs to be kept minimal, but it's a different ball game with system playback.

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    • #32
      It's not about obsolescence, but rather additional tools to accomplish a goal - such as a Phased array sound system
      Click image for larger version

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      "Not a Speaker Designer - Not even on the Internet"
      “Pride is your greatest enemy, humility is your greatest friend.”
      "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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      • #33
        Phase Delay Enhances 3D Audio

        "Not a Speaker Designer - Not even on the Internet"
        “Pride is your greatest enemy, humility is your greatest friend.”
        "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

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        • #34
          Im curious about the placement of the minidsp is the signal chain. I placed it after my preamp but i had some odd sounding anomalies at a few frequencies and stopped using it. It seems fine for running a passive 2way and a pair of subs with just 2 rca inputs.

          It could have been that my signal chain was different on the measurements.

          Cdplayer - minidsp - apa150 - L/R channels plugged into a tweeter and woofer. Ill have to mess around with it again. I used an apa 150 when i took my measurements with omnimic but after thinking about it i probably should have went to the preamp then to minidsp then amp.
          My Build Thread's
          Carrera's / Finalist TL's / Speedster TMM's / Speedster MTM Center / Overnight Sensation Surrounds

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          • #35
            Originally posted by Sydney View Post
            I don't think people are interpreting his question the same way I am. Either that or not reading my response as it relates to his question. I don't see how anything in that link is relevant to the quesiton. This has nothing to do with the general discussion relating to the overall phase, linear phase, or the FIR filters. I shouldn't have said anything because I think the 'phase' part of my comment is getting confused with other discussion related to the added features in the newer revision of the MiniDSP.


            Originally posted by TN Allen View Post
            ...with each driving a 2 way tweeter/woofer combination...
            To me it sounds as though he is asking about connecting multiple drivers to the same amplifier channel. As opposed to the 'norm' of having a separate DSP/amplifier channel for each individual driver, as he has already stated he himself uses. I assume the purpose of the question would be to find out if we could save money by not requiring a separate DSP and amplifier channel, for each driver. So let me try to rephrase his question.

            If you connect a woofer and tweeter together on the same amplifier channel, with only one DSP channel to control both of those drivers within the same channel, and no passive XO network, could you still use the DSP to create a linear output across the speaker pair?

            I was merely suggesting that they will not naturally be in phase, with each other. As they are connected to the same channel, there is no way to adjust their phase independently. So, would you agree that it would generally be a bad idea to attempt to use the DSP to match two drivers connected to the same DSP channel? There are other reasons not to, but I'm just pointing out the phase issue specifically.

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            • #36
              Originally posted by vapor602 View Post
              I don't think people are interpreting his question the same way I am....
              Perhaps not
              "Not a Speaker Designer - Not even on the Internet"
              “Pride is your greatest enemy, humility is your greatest friend.”
              "If the freedom of speech is taken away, then dumb and silent we may be led, like sheep to the slaughter."

              Comment


              • #37
                Originally posted by vapor602 View Post

                I don't think people are interpreting his question the same way I am. Either that or not reading my response as it relates to his question. I don't see how anything in that link is relevant to the quesiton. This has nothing to do with the general discussion relating to the overall phase, linear phase, or the FIR filters. I shouldn't have said anything because I think the 'phase' part of my comment is getting confused with other discussion related to the added features in the newer revision of the MiniDSP.




                To me it sounds as though he is asking about connecting multiple drivers to the same amplifier channel. As opposed to the 'norm' of having a separate DSP/amplifier channel for each individual driver, as he has already stated he himself uses. I assume the purpose of the question would be to find out if we could save money by not requiring a separate DSP and amplifier channel, for each driver. So let me try to rephrase his question.

                If you connect a woofer and tweeter together on the same amplifier channel, with only one DSP channel to control both of those drivers within the same channel, and no passive XO network, could you still use the DSP to create a linear output across the speaker pair?

                I was merely suggesting that they will not naturally be in phase, with each other. As they are connected to the same channel, there is no way to adjust their phase independently. So, would you agree that it would generally be a bad idea to attempt to use the DSP to match two drivers connected to the same DSP channel? There are other reasons not to, but I'm just pointing out the phase issue specifically.
                You have rephrased my question accurately. However my interest is simply curiosity, rather than saving money. Some of what was written in posts previous to my questions, suggested to me the possibility of controlling 2 carefully chosen drivers, a tweeter and woofer, using one MiniDSP channel.

                I ordered a 2X4HD this morning, and have a few extra amps to connect 4 independant channels. This is most likely what I'll do. My primary interest in the 2X4HD is the digital input. I had tried a Minidigi with the 2X4 without success. The 2X4HD digital input seems a better choice. I'm also interested in eliminating preamps. But doing without bass and treble controls may prove unworkable. However, perhaps the 2X4HD can provide a suitable substitue?

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                • #38
                  Originally posted by TN Allen View Post

                  You have rephrased my question accurately. However my interest is simply curiosity, rather than saving money. Some of what was written in posts previous to my questions, suggested to me the possibility of controlling 2 carefully chosen drivers, a tweeter and woofer, using one MiniDSP channel.

                  I ordered a 2X4HD this morning, and have a few extra amps to connect 4 independant channels. This is most likely what I'll do. My primary interest in the 2X4HD is the digital input. I had tried a Minidigi with the 2X4 without success. The 2X4HD digital input seems a better choice. I'm also interested in eliminating preamps. But doing without bass and treble controls may prove unworkable. However, perhaps the 2X4HD can provide a suitable substitue?
                  Maybe I'm not understanding, but why would you connect both a woofer, and a tweeter, to the same DSP channel? Both drivers would end up playing the exact same frequency range, determined by the chosen DSP settings.

                  The MiniDSP isn't really a preamp. Analog volume control isn't possible on it, as it was on the older boards. There's digital, via IR remote, but last I heard it was buggy...but the Dev team was looking into a fix for that, so maybe that's been fixed. The other drawback is that you don't have any visual feedback of where your volume is set with the remote. You'll likely still want to use a preamp before the DSP.

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                  • #39
                    Sorry, should have put that more clearly. There would be a rudimentary crossover, but forget that idea. I have an answer to my question, and probably won't bother trying it. It really was specualtive rather than practical.

                    I have an attenuator for each of the Dynaco amps, and did order the remote with the 2X4HD, though as you say, it may not work well.

                    I found it fairly easy to use the 2X4 and Sure 4X100 to adjust for a suitable sound with a 2 way system, which is to say, I used the MiniDSP for tone control. The cabinets I build have waveguides milled into the front baffles, sometimes a single for the tweeter, sometimes a combination tweeter and midrange. The MiniDSP has been a convenient way to adjust for a pleasant sound. I suspect the wgs would complicate passive crossover design. Given my hearing is compromised, I adjust for what is pleasant for me.

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                    • #40
                      I played around with my MiniDSP 2x4 quite a bit with a 2 way with some very good drivers. I never felt like it sounded as good as with the same drivers with a fairly simple passive crossover even though the active had a flatter/smoother FR.
                      Later I started to play with a 3 way, using the MiniDSP 2x4 to cross between the woofers and a passive XO MT. This is where I feel digital shines... the high cost of passive components at lower frequencies and their interaction with the woofer/mid impedance curves makes the digital xo a better solution.

                      That said I will never ditch passive crossovers... and I will never rule out active/DSP crossovers.
                      Craig

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                      • #41
                        You CAN wire in a pot in the mini DSP 2x4 for analog volume control, though I have not tried it. I just use the source to control it.

                        From the minidsp form:

                        You can think of it more like an attenuator for the inputs. The miniDSP is (essentially) a unity gain device and voltage gain is not possible unless programmed via EQ functions.

                        The volume control provides attenuation from 0db to approximately -49db.

                        Check out this thread for some further info:
                        https://www.minidsp.com/forum/hardwa...trol-questions

                        Scroll down to post# 9071/9072

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                        • #42
                          Originally posted by ani_101 View Post
                          You CAN wire in a pot in the mini DSP 2x4 for analog volume control, though I have not tried it. I just use the source to control it.

                          From the minidsp form:

                          You can think of it more like an attenuator for the inputs. The miniDSP is (essentially) a unity gain device and voltage gain is not possible unless programmed via EQ functions.

                          The volume control provides attenuation from 0db to approximately -49db.

                          Check out this thread for some further info:
                          https://www.minidsp.com/forum/hardwa...trol-questions

                          Scroll down to post# 9071/9072
                          The new MiniDSP actually has a volume control built in, accesible via infrared remote control.
                          Line Array: IDS-25 Clone, FE-83.
                          2-2.5 Way:
                          Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
                          3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

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                          • #43
                            Yes you are right, the regular minidsp 2x4 you can add a volume pot. The 2x4HD is digital.

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                            • #44
                              Originally posted by PWR RYD View Post
                              I played around with my MiniDSP 2x4 quite a bit with a 2 way with some very good drivers. I never felt like it sounded as good as with the same drivers with a fairly simple passive crossover even though the active had a flatter/smoother FR...
                              Were you able to exactly duplicate the passive response curve with the MiniDSP, would the two have sounded the same? Put another way, was the MiniDSP FR possibly too flat?

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                              • #45
                                Originally posted by TN Allen View Post

                                Were you able to exactly duplicate the passive response curve with the MiniDSP, would the two have sounded the same? Put another way, was the MiniDSP FR possibly too flat?
                                You can build a flatter response curve, and with zero phase issues, with the MiniDSP - plus, without parasitic losses, or BSC losses.

                                Simply put, you can't do that with passives. I have no doubts in my mind the MiniDSP would not sound like a passive design. It would sound quite a lot better. You could argue your simpler passive design "sounds better" - but that would be subjectively speaking Objectively speaking, you can't build a crossover as perfect as with the MiniDSP, no matter what you did.

                                That's the whole point I was trying to make. If making accurate, excellent sounding speakers was my original goal, the way to do it is with a MiniDSP, or better. Anything else now seems too compromised (and far more expensive, a passive crossover can be a heck of a lot more costly than a 2x4HD).
                                Line Array: IDS-25 Clone, FE-83.
                                2-2.5 Way:
                                Zaph Audio's winning entry: ZA5+SB29. - Microliths: RS125+RS28. - Small Bangs: TB W4-1658SB+SEAS 27TBFC/G. - Monoliths: Peerless 830884+SEAS 27TBFC/G.
                                3-3.5 Way:Miniliths: SEAS P21/CA21REX+Neo8 PDR+Neo3 PDR. - Megaliths: 2xDayton RS270+2xT-B W4-1337SB+SB29. - ZDT3.5 +: 2xDayton RS180+Dayton RS52+Vifa DQ25. Reflexos: OB 4xDayton RS150 + Neo3 PDR.

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