Recommendations for 12" woofer, 96 db, 4-8ohm, 30ish-2500hz

Discussion in 'Speakers' started by biscuithead, Jun 7, 2017.

  1. gdmoore28

    gdmoore28 Super Member

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    Of course it's an audio sin! And, the more technically-minded among us would view this with absolute disgust. But, as the late, great Zilch once said, "It may harm some perceptions of what sounds good, is all. (But) nobody's going to lose an eye doing it."

    I suspect that you truly enjoy experimentation. I certainly do. And, in this case, what's to be lost by at least trying it? Nothing. Let's see what happens.

    Which JBL fifteens do you intend to use?

    Do you have any mid/high frequency units lying around that might be incorporated here? Do your cabinets have the removable panels where the horn would normally go? Seems this build just sort of begs for a horn capable of being crossed into at about 1200Hz?

    Elitopus - I think you are following this thread. What would you recommend?

    GeeDeeEmm
     
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  2. bowtie427ss

    bowtie427ss arigato gozaimashita Subscriber

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    That outer edge is where the lowest frequencies are reproduced, and the most amplifier power is dissipated.

    The constrained throat creates an acoustic (impedance) transformer, it will affect the "seen" impedance by both the crossover and amplifier, usually raising it in at least the passband where the lens/throat affects it. It will affect the resonant characteristics of the woofer, and without the additional acoustic load of a horn in front of the throat will probably cause cone travel to increase erratically below a certian frequency. How you could predictor simulate this is beyond me.
     
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  3. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    I have some M-115-8, some 2235s, K140s

    I also have some old Peavey Black Widows, and some EVs that I don't remember the model...

    My favorite mid-high horn : The University T-50 driver, and I now have a bunch of H600 waveguides...

    I have many horns to choose from, either for the inside of cabinet or on top. I have 511b , 811b, Emilar bow ties, Renkus Heinz, tons of Altec drivers...

    I just can't get over the 220ti and the recommended WG for it.

    I am pausing on the 15 in the 12 spot though for now... I'm going to give it a few days of thought and research before I waste sweat on an intangible... if that is what it is.
     
  4. bowtie427ss

    bowtie427ss arigato gozaimashita Subscriber

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  5. gdmoore28

    gdmoore28 Super Member

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    OK, you have my attention. So you are saying to use the old Peavey motor on the new style BW basket? What is the story behind this combination? Has Peavey made a significant improvement on the BW?

    I'm particularly interested because back when I worked in ProSound I installed hundreds of Peavey cabinets in churches, clubs, halls, etc.. Their horn drivers usually drove me nuts with early onset of listener fatigue (which I believe was induced by Peavey's tendency to cross their drivers so low that they were driven into distortion very easily). The woofers, though - Scorpions and Black Widows - seemed to be adequate. Just adequate. But they paled in comparison to their JBL and EV counterparts. (Which, I suspect, is why Peavey, until recently, was reticent to publish their T/S parameters. Even now their newest and largest woofers have published Fs numbers in the forties, and Xmax numbers frequently seen in woofers as small as 4".)

    I've often wondered why Peavey, even though they have state of the art manufacturing facilities, play it so safe when it comes to their speaker designs. The only rationale I can come up with is that they are engineering for durability and longevity rather than maximum sonic performance.

    Sorry for the diatribe. Would you fill us in on your recommendation?

    GeeDeeEmm

    From the Peavey Web Site:


    Re is DC resistance of the voice coil in ohms
    Fs is free air resonance of the speaker cone assembly in Hz
    QTS is total quality factor in free air
    QMS is mechanical quality factory
    QES is electrical quality factor
    VAS is equivalent volume compliance of suspension in liters
    No is efficiency in percents
    VD is volume of air displaced in milliliters
    Xmax is T peak-to-peak maximum cone excursion in millimeters

    Model## Re Fs QTS QMS QES VAS No Xmax VD
    1201-8 6.1 59.7 .27 6.6 .28 59 3.8% +/-2.6 143
    1202-4* 4.5 47.1 .25 8.2 .26 100 4.4% +/-2.6 143
    1203-4 3.0 57.8 .37 7.5 .39 72 3.1% +/-1.0 56
    1203-8 6.1 59.4 .38 8.1 .40 69 3.6% +/-1.0 56
    1205-8 5.2 55.6 .28 8.7 .29 69 3.8% +/-4.5 24
    1501-4DT 3.2 46.7 .34 2.4 .40 188 4.6% +/-1.2 84
    1502-4DT 3.2 43.1 .36 7.9 .38 192 3.7% +/-2.8 225
    1502-8DT 6.1 42.4 .32 7.5 .34 205 4.5% +/-2.8 225
    1504-4DT 3.5 31.3 .29 6.2 .32 385 3.6% +/-3.0 240
    1505-4DT 3.2 44.6 .37 8.8 .39 182 4.0% +/-4.8 385
    1505-8DT 5.2 44.2 .37 7.8 .39 198 3.9% +/-4.8 385
    1505KA-8DT 5.3 44.3 .35 8.1 .37 187 4.5% +/-2.6 208
    1801-4 3.5 40.6 .47 8.9 .49 330 4.3% +/-4.6 516
    1801-8 6.5 40.2 .61 8.4 .63 321 3/4% +/-4.8 538

    * inverted dust cap

    [​IMG]
     
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  6. gdmoore28

    gdmoore28 Super Member

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    Boy, I wish I had that kind of variety to choose from. That's a great collection of classic horns and drivers. I'm envious.

    I like the University sound, too. If you happen to have a couple of University N3 crossovers and something like the HF206 "super" tweets on hand, you have a ready-made system. Combine that with your JBL fifteens and you are cookin.'

    A couple of years ago I had a University S6 folding horn with this same mid/high configuration and the sound was very nice - except for the bass response. All was sold, but I still have a pair of N3 crossovers and a couple of HF206 tweets. I've had my eye out for a couple of T50/H600 mids like yours (or maybe a pair of Cobraflex) to assemble a neo-University set of speakers. I'm not a fan of their large woofers, so I'd use something else for the bass cab.

    GeeDeeEmm
     
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  7. bowtie427ss

    bowtie427ss arigato gozaimashita Subscriber

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    Price point(he already has the motors) vs performance. I expect the newer baskets probably use improved materials, there are also oother brand replacement baskets for them with performance options. Check Simply Speakers, Madisound, and Martin Sound Pro.

    The performance differences in any given box between a 1504, 2225, or evm-15B are pretty marginal, when it gets right down to it. The 1801 is an excellent bass guitar speaker, it extends smoothly much higher than any other 18 i know of.

    The 22A driver is a close cousin of the venerable Eminence PSD-2002, it's performance limits are well known. If you hear them cry, they are being overdriven, plain and simple.

    When those Peavey cabinets(not the piezo driver ones) are driven within their ratings, most of them perform quite well. I've been a fan of the SP-2 for decades. For a 2-way PA box it is a very good sounding speaker system, one simply has to observe it's 100 watt rms input rating and you will only hear bad sounds come out of them if you put bad sounds in. If you need more SPL's you add more cabinets, their price point makes this feasible
     
    Last edited: Aug 3, 2017
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  8. bowtie427ss

    bowtie427ss arigato gozaimashita Subscriber

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    so, 2 or 3 hz higher than Altec 515G or the same as a 421-8HII.

    Why you would want to push the resonance on a PRO SOUND woofer lower than that is a mystery to me.
     
  9. bowtie427ss

    bowtie427ss arigato gozaimashita Subscriber

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    It should also be noted that this is incorrect.

    Xmech = maximum physical peak to peak excursion

    Xmax = maximum linear excursion.................. which essentially translates to the point at which power compression begins, or the point at which the cone excursion no longer remains linear to the input power.
     

     

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  10. elitopus

    elitopus Super Member

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    I think one of the cool things about being a "horny", is you can play with different combos of cabs/woofers, and horns/comp drivers.

    I don't let the brand thing stop me. I have had JBL woofers in my Altec cabs. Hey, they sounded pretty good!

    My advice is play around with some of the drivers you have. Or if none of the 15" woofers will fit correctly, start collecting some 12" woofers.

    I find with pro gear, its easier if you use 15" woofers, because they seem to be more common.

    I also don't retune a cab unless I am determined to keep a certain driver in it. And some cabs are harder to retune. Like the Altec 817 cabs I had. It was more about finding the right woofers for the cab, versus the right cab for the woofers.
     
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  11. elitopus

    elitopus Super Member

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    Also, if you noticed on the ebay listing Bowtie posted, those baskets are for 12" woofers. Biscuithead can take his 15" BW drivers, and put the 12" baskets on his existing motors.

    Many manufacturers use the same motor on the 12" and 15" woofers.
     
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  12. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    You have my attention. I had no idea things like this were done. I put the old motors (from a 15) onto a 12"basket... for 75 bucks. NICE.
     
  13. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    I do have a couple extra Acoustic Batons (N3) xovers... but only one extra Cobraflex. I have a pair (unmatched, but mirrored) of 1956 Masters, Masters are one step down from the Dean. I'll have to look to see if I have any HF206s...
     
  14. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    Yep... I have a pile of 15s, not so much with the 12s.
     
  15. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    So... I put this project on hold for a while... but I was just talking to a friend of mine and he said he had some Celestion K12H -200 that he had used with great results in some Karlson Cabs. I have some empty Karlsons and after I gave him some tweeters, he gave me the Celestions. I was originally thinking that I'd put them in the Karlsons, but I now think I'm going to try them in these Jensen cabs with a yet to be determined tweeter...
     
  16. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    I am about to dive into this again this weekend...
    I've been playing with the Celestion K12h-200tc pair for a while with an active crossover... I like it up to ~6000 hz . Although the FR graph shows a decline at 4k :
    upload_2018-1-9_14-8-13.png

    I also had some JBL 2412h-1 drivers laying around the garage, so I thought I'd throw those in since they both spec out at ~ 98db.

    My first build will have simple 2nd order high and low pass passive filters at 6k.
    I expect to need a sub to handle the below 75hz... but I'll give it the ear only test soon.

    I only have about $200 into this build so what the hey-
     
  17. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    I agree. I just can't help but be pleased with a simple two-way design that's topped with a great horn/driver.

    I had these Celestion K12H -200tc pair fall into my lap, and before I just threw them into my Karlsons, I've played with them inside these Jensen cabs... WOW !

    I've played with this 6k cross point, and then 4k... I actually like the 6k point better... and there seems to be very little difference in just running the Full-Ranger wide open ( no crossover)



    I quoted you, to alert you... apologies. So, is there any reason, technically, why I shouldn't run the full range Celestion without a crossover?

    Am I just being sloppy to allow the 6-10k overlap with the woofer and horn? Is there potential comb filtering? Although, I hear no real difference, is there a fundamental rule I am breaking, or just being an amateur? I already have the passive built and installed in one... I just wonder about the effort for the second...


    Sorry for taking this in a different direction with the Full range instead of a more decent (lower reaching) woofer. I have just come to accept the sub-woofers as part of my systems...
    ... and the way these Celestions came to me cheap...
     

     

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  18. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    A lot of speakers are designed that way, woofer running wide open (as it's often called). Depends on whether the overall response curve is actually flat when you do it.

    Comb filtering, possibly. Might be interesting to figure the distance between your driver centers and convert that wavelength to frequency. At that frequency (and above) comb filtering is possible. I think. I fiddled with some of this awhile back on line array design.

    You might also have to play with inverting the polarity of the drivers or not and what that does in the crossover region.

    Finally, the two drivers will have different off axis dispersion, so in the range where they are both playing, it could affect the sound field. Just another of the things that comes into play. I know just enough about this stuff to identify issues. People smarter than me actually know what to do about it. :cool:

    But it can certainly work IMO. First I'd look at the response curve and mess with inverting polarity to hopefully get it flat. The other stuff is smaller potatoes.
     
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  19. biscuithead

    biscuithead Me likes the eargasm retroplasm... Subscriber

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    I'm afraid I'm just smart enough to plug in a soldering iron, and use a chart on how to build a 2nd order crossover. I have the response curve of the woofer from the manufacture... but I don't have a clue on how to arrive at a curve for the combined horn/woofer combo ( or equipment, or how it is measured). The only measurement I've used so far is an A/B comparison between my Cornwalls, Heresys and B&W Matrix1s using the very unsophisticated technique of just listening. My Ma-6200 has the ability to mono, combine L+R in any combination and direct that to whichever channel... I've A/Beed using one channel and both in stereo and mono(but I've only built one cab so far) . I've also reversed polarity on the horn with maybe some noticed differences, but it could have been placebo... I've also added/subtracted a sub in and out... and I like these two-ways better than the Heresy. With this creation being in the 98db region, It is hard to compare with the B&Ws, but I have a gain knob... and for the $$ I've invested, I'm amazed at what a good Full Range 12" can do.

    Perhaps my limited knowledge should be a reason to not continue... but I shall trudge on, and hopefully let some new things trickle into the fat-crusted brain:D... I'm reading...
     
  20. gdmoore28

    gdmoore28 Super Member

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    I'm glad you started posting on this project again, biscuithead. I was wondering what kind of progress you've made.

    GeeDeeEmm
     
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