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Zilch's AK Design Collaborative - Econowave Speaker

Discussion in 'Speakers' started by Zilch, Feb 23, 2008.

  1. Robh3606

    Robh3606 Active Member

    Messages:
    487
    Hello Russell

    Phase is one of those things that is dependent on circumstances. An example is older JBL's are reverse to the standard. As long as you don't mix them with standard phase cabinets all is good. If you mix them with modern cabinets one of them will need to be reveresed so the bass doesn't cancel.

    With drivers in a typical 2 way speaker system, the crossover slope, 12db 18db or 24db is going to have a hand in it. Most 12 db networks have the drivers wired with one phase reversed so they sum properly. 18dB can go either way and 24db are drivers in phase. Another issue can be the drivers physical offsets. A prime example is a longish horn like the old JBL fog horns 2307/2312. The offset and crossover frequency can combine so on a standard 12db network, where the drivers would normally be hooked up opposite phase, they can end up in phase to sum properly.

    Bottom line is it's not as simple as it sounds and you really need to look at it on a case by case systems basis.

    Rob:)
     
  2. JoMoCo

    JoMoCo Cool Clear Water

    Messages:
    107
    Room & Bass & Phase

    Remember the that most influential physical enclosure (next to your ears) is your listening room and the location you listen in. Bass nodes & nulls are location specific and that is why phase is adjustable on most subwoofers systems... so as the saying goes YMMV...adjust as necessary for your room / location / listening pleasure. RTA at the listening position if concerned about what's goin on..and then flip or flop if required by your considered analysis :music:
     
  3. Russellc

    Russellc AK Subscriber Subscriber

    Messages:
    5,752
    Location:
    KC MO
    Ahhh, thanks for the explaination, that makes a little more sense. I appreciate the fast response and consise answer. This really underscores how important having some kind of measuring equipment is!

    Russellc
     
  4. Bauhausler

    Bauhausler Rational Subjectivist

    Messages:
    3,261
    Location:
    Detroit, more or less
    Something peripherally related to ewaves

    I've been working on a related project that's more or less running today.

    Consists of:

    Altec Valencia Utility Cabs
    N800-8K crossovers
    Dayton Classic 15" woofers
    Selenium C210Ti drivers
    Horns equivalent to 811B - brand unlnown
    Other added crossover parts.

    So I lashed all of this up in the Val cabinets. I had a LOT of excess level from the top end due to the original Altec woofer being more sensitive (in the midrange) than the Dayton. I decided to add a fixed LPAD on the top end to bring the variable Lpad's setting down into the middle of the range. For the fixed Lpad I used an 8 Ohm resistor in series and 20 Ohms in shunt, those values being conveniently available. I built the fixed LPAD temporarily on a piece of PPH board and attached it to wires hanging out of a port. On the board I also added capacitors of 2uf, 1uf and .47uf. These caps can be clipped into the circuit to bypass the 8 Ohm series resistor as a form of HF compensation. Please see the rough sketch below.
    The speakers sound decent and the balance is pretty good. I don't understand why adding in the parallel compensation cap doesn't make a bigger difference. There's maybe a 2db increase in level at 8Khz. Barely audible. I would have thought that it would be a lot more. I can fool with the values outside the speaker. Should I be trying different R and C values in the compensation filter?
     

    Attached Files:

  5. Zilch

    Zilch Curve Junkie Subscriber

    Messages:
    12,484
    Location:
    Berkeley, CA
    It certainly should, but:

    1) You've got to boost the HF level to hear it; otherwise you're just attenuating the midrange output of the horn.

    2) 811B and equivalent, presumably, beam the VHF. Listen on axis only, or you wont hear it.
     
  6. Bauhausler

    Bauhausler Rational Subjectivist

    Messages:
    3,261
    Location:
    Detroit, more or less
    The HF level was way too high to begin with, at least with these stiff new woofers. I'm hoping to get some more sensitivity out of the bottom end as the woofers get some hours on them. This fixed Lpad brings the HF down enough that the variable Lpad is now more or less in the middle of the range instead of 3/4 turned off.

    The beamy characteristic of the 811B is what led me to prefer the CD horns over them. These speakers are sort of an experiment to see what I can get out of cabinets and horns on hand. They'll probably end up in the hands of a local musician or DJ after - or possibly before - I'm done fooling with them.

    The Dayton Classic 15" shows promise in this cabinet. With one port closed and some boundary reinforcement I get usable output below 40 hz and a ton of slam in the midbass.
    If possible (space, $$) I'll keep these around so I can try out this cab/woofer as the bottom end of some active 3-way systems with the ewave on top and some kind of midbass between ( B110, Dyna A25, Altec 406, etc.)
    This bottom end certainly has a lot of Authority.
     
  7. Zilch

    Zilch Curve Junkie Subscriber

    Messages:
    12,484
    Location:
    Berkeley, CA
    To be more specific, 0.47 uF will give you the most boost, but you'll have to dial your adjustable toward max SPL to hear it, because the cap attenuates the midband, which must be brought back into balance with the woofer.
     
  8. Bauhausler

    Bauhausler Rational Subjectivist

    Messages:
    3,261
    Location:
    Detroit, more or less
    thx for the additional explanation.
    had a small accident. right hand temp. out of commission. nothing serious. offline 4 a while to get bleeding thumb under control.
     
  9. Russellc

    Russellc AK Subscriber Subscriber

    Messages:
    5,752
    Location:
    KC MO
    Interesting, i am interested in how the Dayton Classic drivers work in E'wave.

    :lurk::lurk::lurk:

    russellc
     
  10. tubino

    tubino A guy with too many tubes

    Messages:
    2,451
    Location:
    Toledo, Ohio
    Do I have a MegaWave?

    My *big* speaker project uses a 2" throat constant directivity horn, currently with JBL 2441. It's a B&C ME60 2" 60x40. Parts Express #294-624. Minimum frequency: 800 Hz *Dimensions: 9.3"H x 10.6"W x 7.9"D. LF is a shootout between Altec 515E and JBL LE15B in a ~30hz 30cu ft BLH. Crossover is kinda Wayne Parham-inspired, guided by spkrman57, xover at 800hz. AK thread here.

    Is it a MegaWave?
     
  11. lico

    lico Super Member

    Messages:
    1,963
    I might try reversing the phase on my LE14/DE250 Ewaves to see if they sound better after reading this discussion.

    My basic understanding of 2nd order electrical crossovers (disregarding the cabinet and driver alignment) is you have to trade time alignment of the signal applied to both drivers vs. having a flat amplitude response in the crossover region.

    I've compared the LF and HF summed filter response in Spice for my Ewave crossovers, wired both ways. It looks like running the drivers with the same polarity results in about a 3 dB lower response in the 3KHz region, compared to wiring the drivers with opposite polarity. Perhaps that helps with what I think I've read here about the DE250 having a peak in the same region, so wiring with the same polarity helps smooth it out as well as keeping the signal time aligned. It would be really cool to see some measurements in both configurations (hint hint)

    In any case it's all fun and games until I try it out to see if sounds any better. That and damping the backside of the waveguides :)
     
  12. lico

    lico Super Member

    Messages:
    1,963
    I might try reversing the phase on my LE14/DE250 Ewaves to see if they sound better after reading this discussion.

    My basic understanding of 2nd order electrical crossovers (disregarding the cabinet and driver alignment) is you have to trade time alignment of the signal applied to both drivers vs. having a flat amplitude response in the crossover region.

    I've compared the LF and HF summed filter response in Spice for my Ewave crossovers, wired both ways. It looks like running the drivers with the same polarity results in about a 3 dB lower response in the 3KHz region, compared to wiring the drivers with opposite polarity. Perhaps that helps with what I think I've read here about the DE250 having a peak in the same region, so wiring with the same polarity helps smooth it out as well as keeping the signal time aligned. It would be really cool to see some measurements in both configurations (hint hint)

    In any case it's all fun and games until I try it out to see if sounds any better. That and damping the backside of the waveguides :)
     
  13. Russellc

    Russellc AK Subscriber Subscriber

    Messages:
    5,752
    Location:
    KC MO
    Thus far, my scientific wildass guess is that you may be correct. Everytime I think something "sounds better" I temper it with my mis wired L-pad debunkle. I have downloaded True RTA and my next PE order will include the Behringer mic. :thmbsp: then as I figure out something for a preamp or phantom power or whatever, I should be able to have some degree of measuring ability. Also, I'm not sure if my sound card is up to snuff or not...

    Similarly, I have put off learning spice for long enough as well. Time to tackle that so maybe I can answer some of my own questions.:D

    Russellc
     
  14. Bauhausler

    Bauhausler Rational Subjectivist

    Messages:
    3,261
    Location:
    Detroit, more or less
    Because sometimes too much of a good thing is just about right

    Okay, here's an epic pileup of drivers and cabinets. Ignore most of what's shown in these photos. What's actually hooked up is:

    Dayton Classic 15" woofer in Altec Valencia cabinet, run from 200 hz down
    Kef B110 in LS3/5A clone cabinet, run from 200 - 2000 hz, facing forward
    Kef B110 in LS3/5A clone cabinet, run from 200 - 2000 hz,, facing upward
    D220Ti on PH612 WG, run from 2K up.

    Shown but not connected:
    811B clone horns
    Kef T27 tweeters

    I got the idea to use 2 B110 midwoofers from my Linn Isobarik DMS speakers. They have 1 B110 and dome tweeter facing forward and 1 B110 and a dome tweeter facing upward. The dispersion is excellent. In the case of the DMS, the 2 B110s are run out of phase so that's how I set mine up.

    I chose to implement this 2 midrange setup using the Valencia cab for the bottom end because the woofer needs some exercise and also because it's big enough/scratched up so it's convenient to pile stuff on top of.

    I'm running both the mids and the woofer off of Accuphase P-300 power amps, which have nice big meters and level controls. With the relative levels roughly balanced out it looks like the voltage drive levels to the mid and woofer are about the same. The mids of course have a sensitivity advantage by being 2 8 ohm drivers in parallel. This indicates that there's a good chance that the Dayton Classic 15" could be paired with 2 B110 without a severe mismatch in sensitivity.

    I'm still hearing a bit of prominence in the mids on the B110s, so I think I need to hit the crossover parts box and gin up a notch filter for 1khz.
     

    Attached Files:

  15. jimreeves

    jimreeves Poopy & Me

    Messages:
    4,450
    Location:
    New Port Richey, FL
    Is that the "Googlephonic" setup Steve Martin was talking about years ago?
     
  16. Bauhausler

    Bauhausler Rational Subjectivist

    Messages:
    3,261
    Location:
    Detroit, more or less
    Maybe it's the needle!
     
  17. Zilch

    Zilch Curve Junkie Subscriber

    Messages:
    12,484
    Location:
    Berkeley, CA
    Biamp Ready

    Pair of high-efficiency variant E'Wave crossovers set up for conversion to biamp operation later:

    [​IMG]

    Solder lugs on binding posts (they come with,) shown connecting the two filter sections. Use them with another pair of inputs instead, and each section may be driven separately.... :yes:
     

    Attached Files:

    Last edited: Apr 2, 2009
  18. Sir.Byrd

    Sir.Byrd Lunatic Member

    Messages:
    15,549
    Location:
    Seattle, WA
    Excellent!
     
  19. ROSSO

    ROSSO Active Member

    Messages:
    240
    Location:
    Louisville, KY
    Hmmm, I must need a miniumum number of characters here until I figure out how to actually delete the corpus....mea culpa...
     
    Last edited: Apr 2, 2009
  20. BlueFlyingV

    BlueFlyingV Tin Knocker

    Messages:
    173
    Location:
    Houston Tx
    same for me
     
    Last edited: Apr 3, 2009

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