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  • NEO Dan
    replied
    Re: Need help with crossover

    Go for it HeartFixr crossover parts are generally non-polar devices or bi-polar in the case of electrolytic caps. It's the layout that makes the "magic" happen... Sounds like you'll have quite the speaker there, congrats

    Leave a comment:


  • HeartFixr
    replied
    Re: Need help with crossover

    I have almost finished the Econowave Altec 4148B with BMS4552 and QSC waveguide. I have used the crossover schematic designed by Zilch and friends and have this incredibly stupid question. Does it make a difference which end of the inductor or capacitor is wired? Are they polar? I have some iron core inductors and others are wire wound. How am I supposed to tell which lead goes where in the circuit? None of the leads on the inductors or capacitors were labeled as positive or negative.

    Leave a comment:


  • NEO Dan
    replied
    Re: Need help with crossover

    If you want great sound and don't have the inclination to measure and engineer the crossover there are several pre-engineered winners listed already in the beginning of the thread, also a search for SEOS should yield DIY kit options if that's what turns your crank...

    Leave a comment:


  • robertm
    replied
    Re: Need help with crossover

    I vaguely remember some talk about how good the woofers were from the Criterion 100B, placed in 4 ft3 boxes, going down to 35 Hz or so. Any reason why this would be a good approach as an econowave worth giving a shot? My system currently has large advent woofers in a 1.1 ft3 box, wonder if it would be a significant step up to go with these old woofs.

    Leave a comment:


  • HeartFixr
    replied
    Re: Need help with crossover

    Wow, thanks for your brilliant input. The Altec can be mounted either way and can definitely be mounted front/flush and would actually be easier.
    Back to the actual drawing board before I start butchering my wood/MDF.

    Leave a comment:


  • dtruck
    replied

    Leave a comment:


  • HeartFixr
    replied
    Re: Need help with crossover

    Jumping in with both feet, actually I'm all in and trying to build the Econowave Altec GPA 414-8B with QSC waveguide and BMS 4552 compression drivers. In looking at Zilch's picture he had a 3/4" baffle with the waveguide front mounted and the Altec rear mounted. If I use a 1 1/2" front baffle and rear mount the Altec, it will reduce offset z measurement. How big of a deal is this with the crossover and if so, how do I compensate for it?
    BTW, is this speaker ported (which is what I am building)?

    Leave a comment:


  • avincenty
    replied
    Re: Need help with crossover

    When you say you have the L-pad maxed out, you mean no attenuation at all? From the looks of that plot, I'd say you need to dial it back just a bit.

    Here's what Zilch got for the Deluxe measurement.

    http://techtalk.parts-express.com/sh...70#post1624970

    The tweeter response is quite a bit flatter in his measurement. The 2KHz bump is due to the baffle edge protruding. That goes away when the baffle is flat.
    Yes, max HF, no attenuation. I am using a DIY panasonic mic, with the WM-61a capsule. I had applied a generic calibration file, if i remove the calibration, the response flattens out.

    I think i will take them oustside to the yard for a new measurement.

    Leave a comment:


  • Pete Schumacher
    replied
    Re: Need help with crossover

    Originally posted by avincenty View Post
    Thanks Pete.

    I just tried it with the 3012LF crossover values and took some measurements in my listening area. The first thing I noticed is that I need to keep the Lpad maxed out (to your point about sensitivity). However it sounds good. I think the low jaggedness is due to room interaction, the speakers are all the way to the back wall, three feet from the side walls. I tested swapping the polarity of the woofer and the FR shows a huge dip around 1.3Khz. The mic was positioned 1 meter away (spl not calibrated) and between the CTC of the woofer and horn. I believe Zilch decided to forgo horn compensation for the Deluxe crossover. Based on what I am getting, should I include one? I guess If I do that I would need to change the resistor values to have better response from the LPAD. Is there a recommended trick for changing the values?

    Alfredo
    When you say you have the L-pad maxed out, you mean no attenuation at all? From the looks of that plot, I'd say you need to dial it back just a bit.

    Here's what Zilch got for the Deluxe measurement.

    http://techtalk.parts-express.com/sh...70#post1624970

    The tweeter response is quite a bit flatter in his measurement. The 2KHz bump is due to the baffle edge protruding. That goes away when the baffle is flat.

    Leave a comment:


  • avincenty
    replied
    Re: Need help with crossover

    I'd be paying attention to the differences in sensitivity between the 3012 and the JBL. You may need to adjust the L-pad on the tweeter.

    As far as setting the LF cutoff and slope, you do have some contribution from the natural response of the woofer that must be accounted for. I'd start with a 3rd order slope on the DSP . . .
    Thanks Pete.

    I just tried it with the 3012LF crossover values and took some measurements in my listening area. The first thing I noticed is that I need to keep the Lpad maxed out (to your point about sensitivity). However it sounds good. I think the low jaggedness is due to room interaction, the speakers are all the way to the back wall, three feet from the side walls. I tested swapping the polarity of the woofer and the FR shows a huge dip around 1.3Khz. The mic was positioned 1 meter away (spl not calibrated) and between the CTC of the woofer and horn. I believe Zilch decided to forgo horn compensation for the Deluxe crossover. Based on what I am getting, should I include one? I guess If I do that I would need to change the resistor values to have better response from the LPAD. Is there a recommended trick for changing the values?

    Alfredo
    Attached Files

    Leave a comment:


  • Pete Schumacher
    replied
    Re: Need help with crossover

    Originally posted by avincenty View Post
    Thanks Pete,

    I do have a minidsp so maybe i can use it to tune the xo points. Based on the 3012lf xo posted in this forum, is the F6 of the HF 1558hz? So i would set a LR2 at 1558 and then play with the LF till i get the flattest curve. Thing is I already have the components for the 3012LF. I can easily modify the values of the inductor as i have a LCR bridge.

    Alfredo
    I'd be paying attention to the differences in sensitivity between the 3012 and the JBL. You may need to adjust the L-pad on the tweeter.

    As far as setting the LF cutoff and slope, you do have some contribution from the natural response of the woofer that must be accounted for. I'd start with a 3rd order slope on the DSP . . .

    Leave a comment:


  • avincenty
    replied
    Re: Need help with crossover

    Since the woofer you're using has a more extended top end than the 3012LF, the only thing you really need to modify is the woofer XO.

    You may find that you need to increase the filter from 2nd order, to 3rd order overall, so that the woofer acoustic slope follows LR4 in the crossover region.

    You have measurement capability, so modification of the woofer XO shouldn't be too difficult to get dialed in.
    Thanks Pete,

    I do have a minidsp so maybe i can use it to tune the xo points. Based on the 3012lf xo posted in this forum, is the F6 of the HF 1558hz? So i would set a LR2 at 1558 and then play with the LF till i get the flattest curve. Thing is I already have the components for the 3012LF. I can easily modify the values of the inductor as i have a LCR bridge.

    Alfredo

    Leave a comment:


  • Pete Schumacher
    replied
    Re: Need help with crossover

    Originally posted by avincenty View Post
    I decided to give the econowave deluxe a try and purchased the DE250 CD, the QSC waveguide and found locally some vintage JBL2204H woofers. I put the woofer into a 2.8cf cabinet tuned to 52 hz and captured the FR outside in the backyard. I also purchased the crossover board and the componets for the Econowave deluxe for the 3012LF. However, looking at the frequency response from the woofer it is no near the respose of the 3012 LF, Pretty sure that the values for the 3012LF wont work. By looking at the FR the Baffle Step is obvious below 170hz. What crossover point looks good based on the graph? Is 1K doable or is it too close to the limit. My understanding for the values for the 3012LF is that they have been chosen to compensate for the rising midrange response past 1K. I put the values into a RLC calc and it gives a Fc of 684hz. Should I keep the HF crossover intact and just play with the LF inductor? Or should I try LR2 values that are matched for both HF and LF?

    Alfredo
    Since the woofer you're using has a more extended top end than the 3012LF, the only thing you really need to modify is the woofer XO.

    You may find that you need to increase the filter from 2nd order, to 3rd order overall, so that the woofer acoustic slope follows LR4 in the crossover region.

    You have measurement capability, so modification of the woofer XO shouldn't be too difficult to get dialed in.

    Leave a comment:


  • avincenty
    replied
    Need help with crossover

    I decided to give the econowave deluxe a try and purchased the DE250 CD, the QSC waveguide and found locally some vintage JBL2204H woofers. I put the woofer into a 2.8cf cabinet tuned to 52 hz and captured the FR outside in the backyard. I also purchased the crossover board and the componets for the Econowave deluxe for the 3012LF. However, looking at the frequency response from the woofer it is no near the respose of the 3012 LF, Pretty sure that the values for the 3012LF wont work. By looking at the FR the Baffle Step is obvious below 170hz. What crossover point looks good based on the graph? Is 1K doable or is it too close to the limit. My understanding for the values for the 3012LF is that they have been chosen to compensate for the rising midrange response past 1K. I put the values into a RLC calc and it gives a Fc of 684hz. Should I keep the HF crossover intact and just play with the LF inductor? Or should I try LR2 values that are matched for both HF and LF?

    Alfredo
    Attached Files

    Leave a comment:


  • Pete Schumacher
    replied
    Re: Flex Your PCD Mettle:

    You're adding a time delay which shows up on the graph as added phase shift.

    Leave a comment:

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