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Thread: 2x4 minidsp

  1. #1
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    2x4 minidsp

    Hello,

    In my journey in the land of subwooferia I purchased a minidsp to use as an eq for my sub. The sub is in a sealed cabinet so it starts to roll off around 30hz. The unit is a dsp as I'm sure you've figured out. The company that makes it is called minidsp and so is there website. They have many different units with more ins and outs then mine. Mine is primarily made for 2 way crossover duty. You can purchase different plugins from the company though. They allow you to do different things with the dsp.


    Anyway I decided to try and use it to biamp my speakers. I'll use at or around 800hz point. But I'll also be able to test different frequencies now.

    I figured some of you may be interested in the results I get with it. So figured I start this here thread about it. I already have an issue with most digital devices in the signal path. I can't stand the hiss. I know that there's a few good ones out there that have remedied this. We will see if minidsp is one. Since my speakers are of pretty high efficiency, it will be pretty obvious if they have not.

    Nick

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    Ok no more joking around. I got the unit up and running. There is hiss. But its pretty low and doesn't get any louder, didn't expect it to. My speakers are pretty efficient, about 101db watt meter on the woofers alone. On ones of lower eff I doubt you'd notice it.

    As used as tool this thing is great. Change crossover frequencies and crossover type and order with ease. You have a parametric eq's at your disposal. Also delay and polarity switching.

    I'm not going to say what I think of its sound quality yet. I want to spend more time with it. I've only spent half an hour of listening where I wasn't playing with the frequencies. Odd thing is I'm back to the same frequency as my passives were.

    the other cool thing is it can be power via USB. Or there's a connection for dc. The thing is tinny. It will easily fit in your pocket.

    All in all not bad for 100 bucks. It doesn't seem to sound al, that bad either. There I spilled the beans. I'll do more serious listening though and report back.

    Nick

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    Senior Member ivica's Avatar
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    Quote Originally Posted by NickH View Post
    ......
    As used as tool this thing is great. Change crossover frequencies and crossover type and order with ease. You have a parametric eq's at your disposal. Also delay and polarity switching.

    I'm not going to say what I think of its sound quality yet. I want to spend more time with it. I've only spent half an hour of listening where I wasn't playing with the frequencies. Odd thing is I'm back to the same frequency as my passives were.

    ..... I'll do more serious listening though and report back.

    Nick
    Hi Nick,

    Nice to see somebody dealing with miniDSP crossover. As I have understood they apply so call 'bi-quad' IIR digital filters for making crossovers (using DSP). As known IIR filters have not constant group delay either in the pass-band or in stop-band, but there are some known possibilities that unwanted behavior (phase "distortion") of the IIR filters can be reduced to the acceptable values, by using more complicated (with more taps) 'ALL-PASS' filters. My question is :are such structures present in the miniDSP crossover?

    Reagrds
    Ivica

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    Quote Originally Posted by ivica View Post
    Hi Nick,

    My question is :are such structures present in the miniDSP crossover?

    Reagrds
    Ivica

    I have an extremely rudimentary knowledge of this but as far as I can tell, yes.


    There is a basic and advances panel for setting the crossovers. The advance is biquad input panel. There also seems to be a feature for creating the program/ parameters or what ever it is you input there. As I mentioned I know virtually nothing about it.


    This will have to change if it does what you say. Thanks for the heads up.

    Oh Ivica, I finally got a measurement mic. I bought it with the minidsp. Im planning on trying to do some measurement soon. Ive been using rew as a rta.

    Nick

    Here you go: http://www.minidsp.com/applications/...ad-programming
    Last edited by NickH; 08-22-2013 at 06:33 AM. Reason: added something

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    Thanks for sharing Nick. When I was looking at the minidsp, I was planning on using it for subwoofer filtering/management only. The plan was to use a PLLXO for the high pass as I'm doing today.

    Someone here recommended a DBX driverack to sort out a different, complex system. I compared the free software download for both side by side, I noticed something that the minidsp was not advertising. The driverack offered phase rotation as a direct setting. It's possible that I've just not found this setting with the minidsp. It does have a nice selection of filtering for each channel however.

    I've theorized the implementation of "all pass" filters accomplishing the same as phase rotation with DSP. I found some discussion in the link below that looks promising, although a bit more complex.

    http://www.diyaudio.com/forums/minid...orion-asp.html

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    There supposed to be a way to do it. But I just learned about this today. It will take me a bit before I attempt it. Ivica brought this to my attention a few posts down.

    There's a big difference between a driverack and this. The cheapest driverack is around 300 bucks. This is 105.

    I actually bought it for the same reason as you considered it for. But its pretty cool even if you just use it as a design tool for picking a crossover frequency. I spent a bit of time with different frequencies and xover types. Good new is I ended up in the same place as the passive I originally built.

    Considering what it is and how it works, the possibilities are end,ess as to what it can do. Its what the programmers can write.

    I only have the 2.1 cross over plugin. I'll probably get the 2 way.

    At the moment I'm not going to give a opinion on how they sound. I need to spend more time listening before I pass judgement.

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    Ive been listening and palying with settings on the minidsp for a week now. Ive got it dialed in were everything sounds great. Though mycrossover frequency between the bass horns and the 2445's will be a bit controversial. Im using the minidsp and my crossover for a 2 way setup. Its crossed at 400hz with a 48db per octave linkwitz riley crossover. Now before anyone freaks out, its only being driven with a whopping 4 watts. Although I doubt it see's anything close to that.


    But Im very happy with it. Im currently working on a cd compensation on the eq for the 2" drivers. This thing surprised me. I never thought I would be content with a digital device in the signal path. Especially a dsp. Now all I need is another 2x4 so I can go all the way to 3 way active.


    Ive played every type of music I can think of through it. No anomalies can be heard. The highs are crystal clear and so is the bass. Mids are phenomenal.

    Nick

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    Senior Member ivica's Avatar
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    Quote Originally Posted by grey View Post
    Thanks for sharing Nick. When I was looking at the minidsp, I was planning on using it for subwoofer filtering/management only. The plan was to use a PLLXO for the high pass as I'm doing today.

    Someone here recommended a DBX driverack to sort out a different, complex system. I compared the free software download for both side by side, I noticed something that the minidsp was not advertising. The driverack offered phase rotation as a direct setting. It's possible that I've just not found this setting with the minidsp. It does have a nice selection of filtering for each channel however.

    I've theorized the implementation of "all pass" filters accomplishing the same as phase rotation with DSP. I found some discussion in the link below that looks promising, although a bit more complex.

    http://www.diyaudio.com/forums/minid...orion-asp.html
    Ho grey,


    May be I am not right, but it seems to me that with 'miniDSP2x4' boards only, real group-delay compensation is not possible due not present larger number of FIR taps, but if 'miniSHARC' board is used too, then that would be promising solution. I think in such solution 'minDSP2x4' would be used mainly as A-to-D and D-to-A converters, and may be some time delays, and gain (sensitivity of the drivers compensation). May be our member POS ( http://www.audioheritage.org/vbullet...r.php?8209-pos ) can help more.

    Regards
    Ivica

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    You over my pay grade at the moment. Im still reading up on the biquad filter options. But it will be a while before I even attempt it. I cant see how it wouldn't be phase coherent though. It would seem pointless to have options to invert the output signals. Which it does. Or am I interpreting something incorrectly.

    Nick

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    I thought I would put this link in here since the title of the thread is 2x4 minidsp

    http://www.linkwitzlab.com/LXmini/Introduction.htm

  11. #11
    Senior Member Lee in Montreal's Avatar
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    Quote Originally Posted by 4313B View Post
    I thought I would put this link in here since the title of the thread is 2x4 minidsp

    http://www.linkwitzlab.com/LXmini/Introduction.htm
    Hmmm... went to the link and searched for miniDSP info. Found none. Are you sure it is the right thread to post this link?

    @ Nick. The hiss your hear is most likely a problem with gain. Maybe the output of your MiniDSP is not high enough.

  12. #12
    Heather [Senorita member] hjames's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    Hmmm... went to the link and searched for miniDSP info.
    Found none. Are you sure it is the right thread to post this link?

    Quote Originally Posted by 4313B View Post
    I thought I would put this link in here since the title of the thread is 2x4 minidsp
    http://www.linkwitzlab.com/LXmini/Introduction.htm
    Oh god 4313B is a spammer!
    Posting links for some other speakerbrand here!

    I think the desired link is
    http://www.minidsp.com/products/mini...ox/minidsp-2x4
    No affiliation, I don't own one and have gotten no pay or gratuities from those folks.


    Quote Originally Posted by NickH View Post
    Hello,

    In my journey in the land of subwooferia I purchased a minidsp to use as an eq for my sub. The sub is in a sealed cabinet so it starts to roll off around 30hz. The unit is a dsp as I'm sure you've figured out. The company that makes it is called minidsp and so is there website. They have many different units with more ins and outs then mine. Mine is primarily made for 2 way crossover duty. You can purchase different plugins from the company though. They allow you to do different things with the dsp.
    Nick
    2ch: Oppo, JoLida 502CRC, JBL L212, 18ti,240ti; Heath AS101, Von Schweikert VR4
    7.1: Oppo BDP103D, B&K, UREI 809A, JBL B460

  13. #13
    Senior Member Lee in Montreal's Avatar
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    Quote Originally Posted by hjames View Post
    Oh god 4313B is a spammer!
    Posting links for some other speakerbrand here!
    Ah, ah, ah. 4313B has been abducted by aliens, and while he was being probed, the aliens hacked his LH account ;-)

  14. #14
    Heather [Senorita member] hjames's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    Ah, ah, ah. 4313B has been abducted by aliens, and while he was being probed,
    the aliens hacked his LH account ;-)
    Oh god, thats it!
    the probes ... the huge manatee of it all!

    Poor Gisgy
    2ch: Oppo, JoLida 502CRC, JBL L212, 18ti,240ti; Heath AS101, Von Schweikert VR4
    7.1: Oppo BDP103D, B&K, UREI 809A, JBL B460

  15. #15
    Senior Member pos's Avatar
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    Quote Originally Posted by Lee in Montreal View Post
    Hmmm... went to the link and searched for miniDSP info. Found none. Are you sure it is the right thread to post this link?
    I would suggest to reread the linked page (onwards) more carefully

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