Results 1 to 15 of 15

Thread: 4344 Bi-Amp Crossover Question

  1. #1
    Member
    Join Date
    Jul 2013
    Location
    Seattle, WA - US
    Posts
    31

    4344 Bi-Amp Crossover Question

    Hello all,

    I'm in the beginning stages of a 4344 replica. While I've read a ton on this forum regarding similar projects and recommendations I'm still at a loss as to what is a good electronic crossover for this setup. Particularly there is mention that if you're not using a JBL 5234(a), or 5235, there is issues with voltage drives and as such other crossovers would need modified? I have no idea what this voltage drive is or means even after trying to research it (admittedly, I'm no expert in speakers or electronics, but know enough to be dangerous. Anyone know thoughts on this? Are these JBL crossovers the ones to get, or is something that is more readily available appropriate or desirable? Particularly I've been looking at the Crown VFX2A. This would be nice as I just picked up a couple of Crown DC300II A's for the bi-amp. I am probably wrong, but these crossovers appear to do bandpass so could they also help with the potential issue of DC leakage at low frequencies (down to 1hz) that these amps can put out when failing, or am I totally off track here?

    Thanks for any insight

  2. #2
    Heather [Senorita member] hjames's Avatar
    Join Date
    Nov 2005
    Location
    NoVA - DC 'burbs
    Posts
    8,294
    You can start with something simple like an Ashly X1001.
    A number of us went that route - I did with my 4341, Phil did with his 4345 ...
    You can get one fairly inexpensive, its easy to set it for 290Hz crossover,
    easy to set it up with a pair of amps, and if you decide you want something better,
    you can sell it fairly easily and go with something more high end like one of the marchand passives.

    With my system I ran a preamp into the Ashly crossover, which had 2 line level outputs.
    The high split fed an Adcom GFA-555, and the low split fed another Adcom GFA-555.

    Quote Originally Posted by jlwitherell View Post
    Hello all,

    I'm in the beginning stages of a 4344 replica. While I've read a ton on this forum regarding similar projects and recommendations I'm still at a loss as to what is a good electronic crossover for this setup. Particularly there is mention that if you're not using a JBL 5234(a), or 5235, there is issues with voltage drives and as such other crossovers would need modified? I have no idea what this voltage drive is or means even after trying to research it (admittedly, I'm no expert in speakers or electronics, but know enough to be dangerous. Anyone know thoughts on this? Are these JBL crossovers the ones to get, or is something that is more readily available appropriate or desirable? Particularly I've been looking at the Crown VFX2A. This would be nice as I just picked up a couple of Crown DC300II A's for the bi-amp. I am probably wrong, but these crossovers appear to do bandpass so could they also help with the potential issue of DC leakage at low frequencies (down to 1hz) that these amps can put out when failing, or am I totally off track here?

    Thanks for any insight
    2ch: Oppo DV970, JoLida 502CRC, JBL L212, VonSchweikert VR4, Heath Valencias
    7.1: Oppo BDP103D, B&K, 2pr UREI 809A, JBL B460

  3. #3
    Senior Member BMWCCA's Avatar
    Join Date
    Feb 2006
    Location
    Virginia
    Posts
    6,878
    I'm running the Ashly XR1001 on my 4345s with Crown PS 400 and PS 200. I had previously used the DC300A-II and D150A-II but I prefer the PS-series now. I have two Crown VFX2As but haven't tried them in this system. The Ashly is so easy to use and I find no flaws in this setup so I have no desire to stretch to a Marchand at this time. For the price of best Marchand, I could buy mint in-box 250Ti's.
    ". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers

  4. #4
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,275
    I am probably wrong, but these crossovers appear to do bandpass so could they also help with the potential issue of DC leakage at low frequencies (down to 1hz) that these amps can put out when failing, or am I totally off track here?
    No. they come before the amp in the chain, so any protection would be between the amp and the driver

  5. #5
    Senior Member pyonc's Avatar
    Join Date
    Dec 2009
    Location
    Maryland
    Posts
    686
    Well, I've tried both 5234A with factory 4343 cards (300hz) and Ashly 1001. In biamp mode, I use two Crown amps. (According to our forum guru 4313B, JBL studio monitors with 43xx were used exclusively with Crown amps in those days)
    Ashly sounds crisper and brighter to me,
    yet to get the sonic authenticity of the original passive XR,
    you might try 5234A. That's what I heard.

  6. #6
    Member
    Join Date
    Jul 2013
    Location
    Seattle, WA - US
    Posts
    31
    Quote Originally Posted by grumpy View Post
    No. they come before the amp in the chain, so any protection would be between the amp and the driver
    Thanks for all the feedback guys! Much appreciated. Grumpy - thanks for pointing out a "duh" moment . To that note, do you guys have DC protection after the amps when running these Crowns? One more question. I'm currently building Giskard's passive network for the upper three speakers (see below), one thing I haven't seen about this is it's slope. Again, I'm not an expert. Is his design 12db? If so, do I hook up the Ashly (24db) to the low and low mid woofers (or just low?) in reverse polarity (red to red).

    Name:  crossover final.jpg
Views: 700
Size:  59.9 KB

  7. #7
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,275
    Yes (12dB/oct in LF low pass and MF high pass), just the low, and reverse the LF leads (or everything else ... your call) if you switch from 12dB to 24dB slopes
    for the LF-MF crossover.

    DC protection? for everything but the LF, you're covered with the crossover.
    If you don't trust the amp, you could put a bigass fuse inline with one of the
    woofer leads. Probably not a popular suggestion, but ok. There are more complicated
    DIY options that could also work

    http://sound.westhost.com/project33.htm

    or there are many available on ebay (that I can't vouch for, and don't use).

    As cool as old amps can be, I have to wonder about hooking up such a unit to nearly unrepairable (now)
    systems without at least getting it properly serviced and checked out... seems awfully risky. Seems like
    someone here had a number or URL for contacting a crown service center that worked on the older gear.

    Sounds like you're having fun, regardless... which is the point

    Cheers.

  8. #8
    Member
    Join Date
    Jul 2013
    Location
    Seattle, WA - US
    Posts
    31
    Thanks again Grumpy for the solid advice/input. I have the amps currently hooked up and seem fine. I picked them up from a guy who appears to have the knowledge and experience to test them and bring up to spec, and I believe that he did (he even wrote down the actual wattage of each channel along with THD and said on one he had to replace the big blue caps, but that was it). To that end, it is still a bit nerve racking but it sounds like worst case scenario I'd blow the 15's, which I think I can live with or perhaps use a fuse as you mentioned.

  9. #9
    Member
    Join Date
    Jul 2013
    Location
    Seattle, WA - US
    Posts
    31
    I've read somewhere that the passive crossover will only protect speakers in which there is a cap in series in the crossover. The 10" does not have such a cap so would this speaker need a fuse as well, or on the overall highpass (from active crossover) will the series cap for horn and tweeter protect the 10"? Sorry again for my lack of knowledge and experience in this

  10. #10
    Senior Member grumpy's Avatar
    Join Date
    Oct 2003
    Location
    SoCal
    Posts
    5,275
    If using the crossover in post #6 above, there is indeed a pair of 120uF caps in series
    (effectively 60uF) in line with the 2122, which will provide some level of protection,
    but will not prevent abuse of the driver with in-band signals (crank it up loud enough
    and any driver will eventually say bye bye)... Not trying to make you paranoid, but I
    also don't want to oversell the capability of putting a cap in series with a driver.

    Even with a DC step (such as might happen with a failed amplifier), there will be a brief spike...
    it just won't be sustained to the point of heating the voice coil... a large enough spike could
    pop a voice coil out of the gap and still cause damage.

    So... aside from extreme level abuse and equipment failure, you should be fine

  11. #11
    Member
    Join Date
    Jul 2013
    Location
    Seattle, WA - US
    Posts
    31
    Thanks again for your time Grumpy. I should have clarified more about the crossover. Yes, that is what I'm building, but, since I'm using an electronic x-over to bi-amp, all items in the dotted lines will not be used. So, I guess I will need protection on that circuit, if I feel necessary.

    Cheers!

  12. #12
    Member ompdiburi's Avatar
    Join Date
    Mar 2005
    Location
    Italy
    Posts
    38

    4344 "like" Biamping

    Hello all,
    I know this is an old thread , but I was serching for info about bi amping a four ways studio monitor, and this seems to be the most recent one.
    I built a 4344 “like” based on the project I found in this forum, with a couple of changes, I use a 2215A wf and LE 85 driver instead of the 2235H and 2425H. The xover was designed by a local technician and differs also from the project and does not include the woofer network, the 2123H has a 6 dB Hi pass made by 60 uF cap.
    This week I changed the initial DIY analog filter, made using op amps, to aMinidsp 2X4HD, the actual setup is a 12 dB/oct butterworth on the woofer and 6 dB/oct butterworth on the hi section, F is 340 HZ, does any one have any experience using minidsp? Any suggestions? For me is a completely new world, so I am a beginner …
    I will post the filter schematic soon, just in case it could help.
    I also have the UMIK 1 microphone and downloaded the the REW software, but at the moment I have a lot to learn about!
    THX for your help!
    Giuliano

  13. #13
    Senior Member
    Join Date
    Jul 2013
    Location
    Ca
    Posts
    462
    Quote Originally Posted by ompdiburi View Post
    Hello all,
    I know this is an old thread , but I was serching for info about bi amping a four ways studio monitor, and this seems to be the most recent one.
    I built a 4344 “like” based on the project I found in this forum, with a couple of changes, I use a 2215A wf and LE 85 driver instead of the 2235H and 2425H. The xover was designed by a local technician and differs also from the project and does not include the woofer network, the 2123H has a 6 dB Hi pass made by 60 uF cap.
    This week I changed the initial DIY analog filter, made using op amps, to aMinidsp 2X4HD, the actual setup is a 12 dB/oct butterworth on the woofer and 6 dB/oct butterworth on the hi section, F is 340 HZ, does any one have any experience using minidsp? Any suggestions? For me is a completely new world, so I am a beginner …
    I will post the filter schematic soon, just in case it could help.
    I also have the UMIK 1 microphone and downloaded the the REW software, but at the moment I have a lot to learn about!
    THX for your help!
    Giuliano
    This is a crossover for 4344 MKII. But need 2405H, 2425J, 2121H or 2123H and 2235H...
    Attached Images Attached Images  

  14. #14
    Member ompdiburi's Avatar
    Join Date
    Mar 2005
    Location
    Italy
    Posts
    38
    Quote Originally Posted by Challenger604 View Post
    This is a crossover for 4344 MKII. But need 2405H, 2425J, 2121H or 2123H and 2235H...
    Those look very nice! But I don't see any reason to change the woofer and the driver in the actual system, just want to biamp it in the correct way.
    By the way this is the xover schematic of my system:

    Name:  20180810_151953_2.jpg
Views: 205
Size:  101.8 KB

  15. #15
    Member ompdiburi's Avatar
    Join Date
    Mar 2005
    Location
    Italy
    Posts
    38
    The boards

    Name:  20170424_193456 - Copia_2.jpg
Views: 204
Size:  90.5 KB

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Question on amp choice for 4344
    By scorpio in forum Lansing Product DIY Forum
    Replies: 2
    Last Post: 04-19-2011, 09:32 AM
  2. finding a 12dB/Octave Slopes active crossover for 4344
    By loman69 in forum Electronic Crossovers
    Replies: 22
    Last Post: 01-23-2009, 11:19 AM
  3. A quick question about the 4344 in the home
    By Evets in forum Lansing Product General Information
    Replies: 4
    Last Post: 09-10-2006, 11:23 PM
  4. Crossover frequencies in a 4344
    By jarrods in forum Lansing Product Technical Help
    Replies: 4
    Last Post: 06-04-2004, 05:43 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
  •