Thoughts on HLCDs

Discussion in 'OT Technology' started by dbman96, Mar 16, 2005.

  1. dbman96

    dbman96 Active Member

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    Just curious what the OT car audio crew thinks about these.

    I'm picking up a set of Image Dynamics CD-2 mini horns for my WRX front stage. Initially I'll run them with a pair of 6.5s I have onhand; eventually it will become a 3-way stage with 6.5s in the kicks and 8s in the doors. I expect them to require some amount of equalization but I'm using a PC as a source and have essentially unlimited bands of parametric eq wherever I need it (and will be able to apply eq to individual drivers if that ever becomes desireable) so I'm sure I can tame the horns.

    Any experiences with the ID horns out there? Am I setting myself up for a world of trouble? Should I just stick with direct radiating drivers or are the HLCDs worth the trouble?
     
  2. 04

    04 Guest

    I'm a big fan of HLCD's :big grin:

    I've heard good things about the ID horns. But, I personally would just stick with direct radiating drivers in a car environment, unless you need super high output levels or want a specific focused radiating pattern. If you're having a problem with reflections, then HLCD's would also be a good choice IMO.

    Do you listen at really high levels?
     
  3. dbman96

    dbman96 Active Member

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    not yet. :x: I hear such good things about the dynamics of HLCDs that I figure I should explore it. Plus I have a HORRIBLE time getting good on-center imaging in my car, and I understand HLCDs are great for that.

    I figure I'll give 'em a shot. I'm picking them up used, so I know I can sell them for as much as I'm paying if I don't like em.

    Plan B is probably going to be a set of Dynaudio components in the kicks, possibly the 3-way dyns with 8s in the doors. I'm all-active on the xovers and have many channels of amplification to play with, so it'll be an easy transition if I choose to do so.
     
  4. 04

    04 Guest

    Well if you can sell em for about as much as you bought them, then I see no reason not to try them out.

    That Dynaudio setup would be pretty sweet too :eek:
     
  5. dbman96

    dbman96 Active Member

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    I love dyns. Always have. I can do the horns cheaper at the moment, so I'll give 'em a shot.
     
  6. dbman96

    dbman96 Active Member

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    Oh, and I hesitate to admit this since it always draws fire, but one reason I'm looking into HLCDs is that I'm going to experiment with a PC-based TACT-style room correction system as a final step in fine tuning (AFTER I get EQ and driver delay and levels and crossovers all dialed in). I've played with it in-home and it's really quite impressive. But the downside is it results in up to a 10dB cut in signal levels (to prevent clipping the signal before it even hits the DACs). So efficient drivers and big amps are the order of the day. I thought horns might be a good place to start. It may be a big load of crap and completely worthless, but projects like this keep me entertained for months.
     
  7. 04

    04 Guest

    Ah cool :cool:

    That would definately be a cool program to play with, but how do you plan on setting it up in the car? Do you have any measurement equipment? I'd hate to try and set that precise of stuff up by ear :o

    Most of the acoustic affects in the car are due to non-minimum phase errors which can't be properly fixed with an EQ, though IME EQ's can work to fix the sound to a certain extent. I've got an active xover/equilizer/time delay processor in my home system and one of the EQ bands I use is to fix a 40hz room mode. So it can work, but IMO its not as effective as treating with sound damping material :o
     
  8. dbman96

    dbman96 Active Member

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    The procedure involves running a sine sweep at high volume through the system and recording the response with a microphone (I've got a calibration curve for my mic) looping it back into the software, and then generating an FIR filter to correct for frequency and impulse response. I've also got access to an oscilloscope with RTA capabilities so I'll be able to even out the driver levels and overall freq response before I ever throw it into an automated software procedure.

    I've experimented with this in a home audio environment, and even a quick half-assed setup attempt at it literally made the room and speakers go nearly transparent. Freq response wasn't ideal (due to my quick and dirty setup and horrible mic at the time), but the soundstage was so cohesive it was almost preferable to deal with the "flat" sound and enjoy the imaging.

    Obviously there are limitations to how much you can accomplish through this, and it's only for ONE listening sweet spot so I'll have calibrations for myself and for a passenger, and I'll just kill the correction on the rare occasion that I'm actually hauling people. I'll naturally be doing extensive sound deadening of the vehicle before I even start with any of this.
     
  9. dbman96

    dbman96 Active Member

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    Example waterfall plots of one user's in-room response with very high-end speakers and room treatments (this is a VERY well done setup, the room treatments are obviously doing a damn good job already):

    [​IMG]


    And this is the impulse response of the same room with DRC software applied:

    [​IMG]
     
  10. 04

    04 Guest

    :eek: :eek: :eek: :eek:

    Thats an awesome waterfall plot. Do you have any pictures of that guys setup?
     
  11. 04

    04 Guest


    :cool:

    Man I need to get that software! Is it free, or a commercial product? I've got a Behringer DCX 2496 which has multiple parameteric EQ bands per channel, I could probably use it in a similar fashion.

    What mic are you using? Also, how did the filter take care of the time domain issues? Does it somehow apply an out of phase signal after the input ceases in order to cancel out the ringing?
     
  12. Bavarian3

    Bavarian3 OT Supporter

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    i use cd1pro MH. I have them with some 6.5" modded ID CX mids. I got a chance to listen to everything for a while in a temporary install, and it was great, tons of midbass, reallly high stage and width. Horns also get really loud, and should be given very little power. 10-20 watts is plenty. Im now trying to finish my new install with the custom kick panels before some local competitions :x:
     
  13. dbman96

    dbman96 Active Member

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    The software is free, but of course has NO user interface whatsoever. There's a page about it at http://drc.wildgooses.com/index.php/Main_Page

    If you hunt around there's tons of information. I don't have the faintest idea how it actually works. Lots of math.
     
  14. dbman96

    dbman96 Active Member

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    Noice!

    How were the 6.5s modded? I've got a really solid set of DEI 6.5s that I'll use at first but I KNOW they're going to be the limiting factor for max volume. Ultimately I need to get some 8s.
     
  15. Bavarian3

    Bavarian3 OT Supporter

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    They have a poly cone, suposedly some prototype technology thats gona be on the new IDQ's that are going to come back out.
    3 way is alwayss better of course, but if youre going to use 8's, no need for 6.5" midranges..just use a 4".
     
  16. dbman96

    dbman96 Active Member

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    Really? I've always heard that 4s just don't have the output to bridge the gap between 8s and horns. I consistently hear that for a 3way setup it's wise to use 8-6.5-hlcd
     
  17. Bavarian3

    Bavarian3 OT Supporter

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    well i supose it depends on what 8" drive youre gona use. There are 8" drivers that can solely be paired with a set of horns for a complete front stage.
     
  18. dbman96

    dbman96 Active Member

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    Yeah, the horns I'm using reach down to 900hz easy, but the problem is, 8"s in the doors have pretty poor dispersion of upper midrange frequencies generally, and fitting 8s in the kicks is just madness.
     
  19. Bavarian3

    Bavarian3 OT Supporter

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    werd...i dont know that id want to put 8's in the doors though.
     
  20. dbman96

    dbman96 Active Member

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    It would be a nasty job. I'm still debating it, I don't REALLY want to fabricate custom door panels.
     

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