Page 1 of 2 12 LastLast
Results 1 to 15 of 24

Thread: DSP/room eq and 4430's

  1. #1
    Junior Member ricesinice's Avatar
    Join Date
    Mar 2005
    Location
    Massachusetts
    Posts
    12

    DSP/room eq and 4430's

    I built a pair of 4430 clones a few years ago with the help of this forum, now I am hoping you all can help again with what seems should be a problem a lot of us think about.
    I play most of my music through a CD player, or a laptop so, the source is digital ,then it gets converted to analog, goes into my driverack where the signal gets converted back to digital to get EQed to compensate for the room acoustics then back to analog to go to the preamp. It seems like there should be a fairly easy, and good audio quality way to not have to go through the extra conversion to get the room eq. Does someone know of a way to do this with an external sound card that would have digital inputs, and the ability for mic input to get the room acoustics, and save the profile to call up at a later date, or all the time, like the driverack....... and not cost too much?
    Thanks,
    Rob

  2. #2
    Senior Member
    Join Date
    Oct 2007
    Location
    Hungary
    Posts
    179
    Driverack should have, and if it has no digital io thats real strange. Maybe it works on some obscure sampling rate then.
    Either you think out-of-the box and spend huge pile of bucks on DEQX then go for the monoblocks ( still need preamps) way or...
    basically you can do everything inside the PC , Vista comes with room correction built-in and anyway, audio engine rewritten from scratch .

    You can apply the frequency correction EQ inside PC, but Im not sure how much is it worth , the JBL's should be flat as they are (thats the point hahaha) . If you overcorrect some peaks, it is going to fold back off axis, leaving you a 10 cm sweet spot , then equal or worse outside. My intention doing digital stuff is to use digital crossover , every driver has its own DtoA converter. This is no simple stuff. Im goin to document everything but there are months ahead

  3. #3
    Senior Seņor boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    7,007
    Quote Originally Posted by ricesinice View Post
    I...It seems like there should be a fairly easy, and good audio quality way to not have to go through the extra conversion to get the room eq. Does someone know of a way to do this with an external sound card that would have digital inputs, and the ability for mic input to get the room acoustics, and save the profile to call up at a later date, or all the time, like the driverack....... and not cost too much?
    You lost me. You talk of using a mic input, which would be analogue.

    What "extra" conversion?

    How do you presently measure the room response to set your "compensation EQ" in the DR?

    Regardless of that confusion on my part, some use SmaartLIVE, which is analogue. Using a Fast Fourier Transform algorithm (FFT) it allows the comparing of two signals - a reference signal (time delayed) to an acoustic measurement signal. You then manually adjust the outboard EQ to suit. There are maybe 16 screenshots you can save. It is not inexpensive, and incredibly powerful.
    bo

    "Indeed, not!!"

  4. #4
    Senior Member
    Join Date
    Oct 2007
    Location
    Hungary
    Posts
    179
    I think I get it what he means, he wants to be self contained without the physical help of others right ? Thats quite daunting task to begin with. I personally want to avoid restricting myself to DRC cause I dont trust it. It is only recently our inventory and computers became powerful enough to do it. Also, measuring the room is crucial. Thats why I think about hiring a professional , rather than buying the DEQX while its hot . Then the guy tells me what I can do with the room, maybe even complete redo from scratch ( soffit mounting, hell yeah !!) , hehe. If I'am done with that, then the need for room correction might be as useless , given the JBL's ability & attributes.

  5. #5
    Junior Member ricesinice's Avatar
    Join Date
    Mar 2005
    Location
    Massachusetts
    Posts
    12
    No, my driverack does not have digital input (wish it did).
    I want the mic input to eq the room with the pink noise like I do with the driverack which eq's the speakers for the response I select automagicly.
    I just want to have the ability to eq rooms to get a decently flat response, and do it all before the music goes analog. There is software I just found and have not tried it yet called Room EQ Wizard that looks promising.
    I did look at the Smartlive but, it is way above my budget.

  6. #6
    Senior Seņor boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    7,007
    Quote Originally Posted by ricesinice View Post
    I just want to ... do it all before the music goes analog.


    -----

    I gotta add - I don't see what the difference is, doing it in the digital or analogue domain. You are making EQ corrections supported by the room response. Why and/or how would it be different?

  7. #7
    Senior Member
    Join Date
    Jul 2003
    Location
    Orange County, CA
    Posts
    3,090
    Quote Originally Posted by boputnam View Post


    -----

    I gotta add - I don't see what the difference is, doing it in the digital or analogue domain. You are making EQ corrections supported by the room response. Why and/or how would it be different?
    Possible phase shift as well as the introduction of extraneous noise associated with the analog circuitry.

  8. #8
    Senior Seņor boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    7,007
    Well, perhaps, but if that is what it "sounds" like, I'd rather correct into that, then into something not final.

  9. #9
    Senior Member
    Join Date
    Oct 2007
    Location
    Hungary
    Posts
    179
    someone wrote he was inbetween + - 1 dB in the upper octaves when he fitted a TAD2002 onto the 2344 horn. Also look at 2234 or 2235h measurements, they are essentially perfect !! When I saw the 2235h response curve in simulator, that moment marks my entry into the JBL world



    I want to open a soffit mounting topic

  10. #10
    Senior Member
    Join Date
    Oct 2007
    Location
    Hungary
    Posts
    179
    you cannot correct the sub 100hz region by means of linear phase FIR filtering, its ridiculusly inefficient, nothinh would do it. That region must be taken care by IIR filters , these are close to their analog counterparts in phase shifting behavior ( ringing after transients), analog might do even better here . I myself dont want *any* type of filtering to take place there. All I want is phase optimised crossovers az 1khz (again , no linear phase either ) .

  11. #11
    Senior Seņor boputnam's Avatar
    Join Date
    Apr 2003
    Location
    northern california
    Posts
    7,007
    Quote Originally Posted by readswift View Post
    ...All I want is phase optimised crossovers ...
    AI would add is "coherant phase", too.

  12. #12
    Senior Member
    Join Date
    Oct 2007
    Location
    Hungary
    Posts
    179
    best summation ever can be read here: http://hypex.nl/docs/Bruno%20Masterclass/slides.htm

    have to scroll quite a lot

  13. #13
    Junior Member ricesinice's Avatar
    Join Date
    Mar 2005
    Location
    Massachusetts
    Posts
    12
    The thing is, I am doing 2 Digital to Analog conversions to go through the Driverack,(I assume the driverack does the auto EQ wizard in the digital domain) when I use a digital source. I would like to have only one D to A conversion and hopefully do the room corrections before it goes analog.

  14. #14
    Senior Member
    Join Date
    Oct 2007
    Location
    Hungary
    Posts
    179
    if my suggestion is right, and the driverack has obscure sampling rate ( please link online manual or copy the text here) it would need hardware hackery, doable, but if it worths, that depends solely on the quality of components inside the driverack. So you may want to open it and post pictures

  15. #15
    Senior Member UreiCollector's Avatar
    Join Date
    Dec 2005
    Location
    NY. USA.
    Posts
    218

    D to A to D to A

    Quote Originally Posted by ricesinice View Post
    ...the source is digital ,then it gets converted to analog, goes into my driverack where the signal gets converted back to digital to get EQed to compensate for the room acoustics then back to analog to go to the preamp.
    I think I know what Rob is getting at. He wants to avoid the D to A to D to A, and go D, D, A. without the additional A to D and D to A steps in the middle......yada yada yada....he wants to stay digital, do all his processing, and then go analog once all else is finished......

    The 'holy grail' in digital audio is to stay in the digital domain as long as possible, without conversion to analog, and subsequent re-sampling back to the digital domain (sometimes at inferior sample rates, especially if your a super-audio fan).

    Unfortuantely from what Rob is saying, his driverack does not have digital inputs, so running his computer/cd straight to that box in the digital domain for EQ'ing is out of the question.

    For most of us $ is a limiting factor, and we must make compromises. I personally chose to only use my digital crossover on the subwoofers (JBL 2242H's), where the possible negative effects are hopefully not audiable (thus avoiding an A to D, and D to A process on my "mains"). I'm high-passing my mains, and low-passing my subs in the analog domain ahead of my digital crossover/eq.....thus EQ is only applied to my subs (and some high pass at 20hz, but that's another story).

    I really think your biggest benefit of EQ will be had below 150hz (ie, use your driverack on the subwoofers only). For any issues above that, I would look into room treatment to correct.

    This way, no new equip to buy....and you'll probably end up with a better sounding system.

    Best luck, and happy listening!
    Frederick "The Urei Collector"

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •