Page 31 of 58 FirstFirst ... 21293031323341 ... LastLast
Results 451 to 465 of 864

Thread: Project M2 DIY Thread

  1. #451
    Member
    Join Date
    Jul 2017
    Location
    Florida
    Posts
    65
    Quote Originally Posted by pos View Post
    The measurement is noisy but everything looks good
    Thanks yet again

    I'm quite pleased at least the q-sys hardware is shown to be a viable substitute, and I don't have to buy three of the OpenDRC DSP's .

    What do you think about the measurements from the Q-SYS dsp using the full 6144 taps.
    It does not appear to be truncating the signal at all, it looks to be virtually identical to the measurements taken using 4096 taps + PEQ.

  2. #452
    Senior Member pos's Avatar
    Join Date
    May 2007
    Location
    France
    Posts
    2,628
    Quote Originally Posted by lesliew View Post
    It does not appear to be truncating the signal at all, it looks to be virtually identical to the measurements taken using 4096 taps + PEQ.
    Difficult to say as the HF part does not need that much taps anyway (1024 would be enough), and the LF part is not using the same rephase settings for the 6144 and 4096 taps FIRs.

    Here is something you can try:
    https://pastebin.com/raw/LJSUZUaT

    It is a very simple minimum-phase correction centered at the 5000th sample, 6144 taps total.
    If the QSC does truncate to 4096 taps then it should only get (near) zeros, and you should get a (near) -Inf magnitude response.
    If you see (and measure!) the intended correction then it means your QSC does not truncate to 4096 taps.
    In this case you can try different values of taps and centering and see how far you can get!

  3. #453
    Junior Member
    Join Date
    Nov 2011
    Location
    Sweden
    Posts
    12
    Do you know if there is any difference on the D2430k tweeter for the jbl VTX series versus the D2430k to the M2?
    And can I use my Crown DSi to set the EQ crossover for the M2 that POS have created?
    I am planing do start my own M2 clone project and is completely new to DIY speaker building, so all the help I can get here at the beginning is certainly welcome!

    Best Regards Per

  4. #454
    Senior Member
    Join Date
    Nov 2008
    Location
    Gothenburg, Sweden
    Posts
    761
    Nice to see you here Fischer M2 in your cinema front would be world-class

    There exists different ohm-versions of D2430k. I think M2 uses 32ohm version.

    You can maybe try to enter the M2-settings into your amp, and see if they fit?

    Reading this whole thread would be the best start I guess.

    User Kalle (from Sweden) built a pair of M2, I think he has CNC-drawings for his boxes. Maybe you can try contact him. I have his email if you need.

    /bubbleboy76 (a.k.a rajapruk on forum component.se, faktiskt.se and diyaudio.com)

  5. #455
    Senior Member Kalle's Avatar
    Join Date
    Jul 2013
    Location
    Sweden
    Posts
    124
    Quote Originally Posted by Fischer View Post
    Do you know if there is any difference on the D2430k tweeter for the jbl VTX series versus the D2430k to the M2?
    And can I use my Crown DSi to set the EQ crossover for the M2 that POS have created?
    I am planing do start my own M2 clone project and is completely new to DIY speaker building, so all the help I can get here at the beginning is certainly welcome!

    Best Regards Per
    Hello Per,
    Klart du skall bygga M2, de är grymma! Va det du som idag har en ganska rejäl Pro Cinema? 3722?!
    I got 2 D2 drivers for sale in Sweden and some more stuff for M2, Amp/DSP. I think you can get your DSi working but you have to redoo the DSP-setting. I can help with boxes if you want.

    PS, I`m going to Florida tomorrow and thinking of if it`s possible to get the grilles for M2 in the luggage:o I need them for my clones.


    Regards Kalle

  6. #456
    Senior Member pos's Avatar
    Join Date
    May 2007
    Location
    France
    Posts
    2,628
    For anyone interested, here is a Crown DSi device file for the M2 settings that I compiled for member Fischer: M2.DSi.Device.zip

    channel 1 is LF, channel 2 is HF.

    It is not tested (caveat emptor), but should hopefully replicate original Crown Itech settings +/- 0.2dB

    There is provision for a 20Hz subsonic filter in the crossover section for high SPL applications, and in this case 21.5dB EQ gain setting should be increased by around 3dB to compensate...

    EQ and shelving types and implementations look identical between Itech and DSi, but the DSi does not have 36dB/oct filters so I had to cascade two Butterworth filters, 12dB/oct (pre EQ section) and 24dB/oct (crossover section), resulting in a LR 36dB/oct approximation (0.2dB difference). The DSi also has a 0.5dB precision in EQ gain values, so original values had to be approximated, especially for the woofer, resulting in a max 0.2dB difference again. All in all it should be pretty close, and well within driver-to-driver consistency tolerance...

  7. #457
    Senior Member
    Join Date
    Aug 2010
    Location
    Jättendal (Giant Valley), Sweden
    Posts
    763

  8. #458
    Senior Member pos's Avatar
    Join Date
    May 2007
    Location
    France
    Posts
    2,628
    Yes, and they even have an "high end" version of that driver: http://www.bmsspeakers.com/index.php...99he_overview0
    But it is a midrange driver :

  9. #459
    Senior Member ivica's Avatar
    Join Date
    Jan 2008
    Location
    serbia
    Posts
    1,703

    Wink

    Quote Originally Posted by pos View Post
    Yes, and they even have an "high end" version of that driver: http://www.bmsspeakers.com/index.php...99he_overview0
    But it is a midrange driver :
    Hi POS,

    Yes, it seems to that such driver would very good solution for railway station announcing....

    regards
    ivica

  10. #460
    Senior Member baldrick's Avatar
    Join Date
    Feb 2006
    Location
    Haugesund, Norway
    Posts
    824
    Any good source for suitable ports for M2 clones? Preferably e-bay since shipping could to be an dealbreaker. 10x vents from Parts Express was aprox $200 in shipping

  11. #461
    Senior Member Odd's Avatar
    Join Date
    May 2009
    Location
    Oslo, Norway ------ Now Portugal
    Posts
    809
    Quote Originally Posted by baldrick View Post
    Any good source for suitable ports for M2 clones? Preferably e-bay since shipping could to be an dealbreaker. 10x vents from Parts Express was aprox $200 in shipping
    Use USPS from US
    43XX (2235-2123-2450-2405-CC 3155)5235-4412-4406-4401-L250-18Ti-L40-S109 Aquarius lV-C38 (030) 305P MkII

  12. #462
    Senior Member baldrick's Avatar
    Join Date
    Feb 2006
    Location
    Haugesund, Norway
    Posts
    824
    Any reason to not buy 2 of theese for each port? (Looks quite Nice)

    https://www.ebay.com/itm/1pcs-93-135...UAAOSw5j9Zg0Zh

    Or maybe these are better?

    https://www.ebay.com/itm/1pcs-98-235...UAAOSwq9lZgzuC

  13. #463
    Senior Member pos's Avatar
    Join Date
    May 2007
    Location
    France
    Posts
    2,628
    I went for the JET 70 series that can be found in various european web shops (intertechnik, etc.).
    It comes in different parts that you need to buy separately and assemble: inner flare, outer flare (with screw holes) and middle tube (to be cut to a given length).
    I used inner flares on both sides to avoid visible screw holes and glued them on the front baffle.

    https://www.hifisound.de/Do-it-yourself-Products/Loudspeaker-Accessories/Bassreflex-Tube/IT-Bass-Reflex-System-JET-Set-70.html



  14. #464
    Senior Member
    Join Date
    Feb 2018
    Location
    Annapolis, MD
    Posts
    194

    How to service the M2s compression driver after assembly

    Hello all. I've been reading this thread with great interest. I'm fabricating an M2 clone (5 of them actually, and it is a good friend that is doing the fabricating part since I'm not the carpenter and it took him just a few hours to make our prototype) and the thought occurs to me... While putting the horn (waveguide), bracket and D2 on while the inside faceplate is still accessible is one thing, what is everyone doing about being able to service the thing once it is fully assembled? Let's say you need to change the D2 due to damage or desire to experiment with alternative drivers (e.g 2450SL). How easy/hard is it to get at the screws/nuts that hold the driver on? It seems like a very difficult/contortion to get through the woofer hole up through a support plate hole(s) to get at the hardware.

    I'm toying with just making the rear of the cabinet have an access plate that is removable that will make the driver completely accessible.

    My M2s will be in my home theatre and situated completely behind a traditional screen/front-end so the esthetics of the speaker, for me are a non-issue. I plan to have the rear of the speaker accessible (space behind the screen/speaker for a person to be able to stand.

    Lastly, my DSP will be QSC's Q-SYS platform. Has anyone here used it before for the M2? I've created a speaker voicing based on the crossover information provided elsewhere (it is at least a good starting point). I believe I've seen in other places that someone has come up with FIR solutions for Q-SYS. But before going over-the-top, I'm going to want to measure/listen to my actual units. Whereas I'm going to be playing mine through a sheet of vinyl (with either micro-perfs or woven), there will be response variances associated with that whole process too.

    This has been a great thread for me. I was this close <real small space> to going with an Altec 604/620 clone (I own a pair of 604Gs and have always liked the 604) but NOBODY seems to dislike the M2 so I figured the best way to find out is build one and listen to the thing.
    Attached Images Attached Images  
    Last edited by sguttag; 02-13-2018 at 05:53 AM. Reason: Picture was rotated.

  15. #465
    Senior Member
    Join Date
    Oct 2014
    Location
    Iceland
    Posts
    140
    I attached the waveguide using wingnuts, so it is possible to remove it through the woofer hole.
    Its not fun and takes forever and hurts the arm bending it through the bracing and what not, but possible if needed.

    A rear service hatch is definately a way more practical way of doing it!

Thread Information

Users Browsing this Thread

There are currently 4 users browsing this thread. (0 members and 4 guests)

Similar Threads

  1. JBL LN3 Project, *Official Thread
    By Nightbrace in forum Lansing Product DIY Forum
    Replies: 58
    Last Post: 07-13-2016, 03:08 PM
  2. Fundraising request; donations to Lansing Heritage Project May loudspeaker project
    By mikebake in forum Lansing Product General Information
    Replies: 7
    Last Post: 04-21-2011, 12:37 PM
  3. Project May, similar privat project?
    By Flodstroem in forum Lansing Product DIY Forum
    Replies: 14
    Last Post: 02-21-2007, 03:42 PM

Posting Permissions

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