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Thread: JBL 2225 vs. Altec 515

  1. #1
    RacerXtreme
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    JBL 2225 vs. Altec 515

    Can someone explain to me the difference between overhung and underhung voice coils ? On the Altec Lansing Forum site we were discussing the pros and cons of installing 400 watt JBL 2225's into Altec 210 VOTT cabinets and how they would compare to the 75 watt Altec 515's that originally came in them. Jim Dickenson - think he's the president of Iconic speaker corp. (and a noted expert on the big Altec theater stuff) said this:

    "An A2 has a 1M/1 watt rating of about 114 db. The mutual coupling of the 2 210 bass horns is to below 50 Hz at full level! A good 515 with a paper voice coil support handles 75 Watts AES. This gives you a max continuous SPL of about 140 at a Meter, go to 150 for peaks.

    The JBL unit will handle 500 watts AES, has 98 db 1 W 1M efficiency. Max Spl is about 127 at Max. 137 at peak. It would take the JBL 2000 Watts to get to the same continuous level as the A2 at 300, the speaker simply will not handle the power. Who is more digital ready??? It is just simple math, every time you double the power you get an increase of 3 dB. The more efficient speaker wins every time. The JBLs have heavy inarticulate cones with clumsy overhung voice coils. The ALTECs and now our Iconics have light moving mass with underhung voice coils. You could simply have your 515s reconed with High Temp Voice coils and double their power handling, something we will be doing soon with our new 166 model. We have already done it with our 164 which is more intended for short bass horns and venjted boxes. It would work way better than any JBL in a 210, even though we do not recommend it for that use. Even a cast frame Eminence (3" VC) will sound better in these boxes than a JBL 2227.


    The fellow above has a very old set of A2s, complete with original 515s, yes the software is probably aged, everything wears out sometime, have it repaired, not thrown away for something that does not work as well. Put new 299 style diaphragms in the drivers, then they will handle as much power as the JBLs and sound better, then biamp the system and watch the customers come to the show because "it does not hurt their ears" and sounds better. I could go on and on..... JIM "


    So JBL 2225's have heavy inarticulate cones with clumsy overhung voice coils? It just seems like 400 watts into 8 JBL 2225's will blow away 75 watts into 8 Altec 515's. I don't quite get it...............



    Guy

  2. #2
    Senior Member "Duke" Spinner's Avatar
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    don't count on it.....

  3. #3
    Dang. Amateur speakerdave's Avatar
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    Well, I can respond to some of this:

    "Underhung" means that the voice coil gap structure is deep enough that the voice coil, even at full excursion, is always completely within the gap. Produces linearity and efficiency.

    "Overhung" is the opposite. An overhung arrangement can be linear as long as the whole gap is always occupied by an equivalent portion of the voice coil. This arrangement can be used for longer excursions at a sacrifice of some efficiency.

    In general I would say that woofer design is a series of tradeoffs, and decisions are made based on design goals. I see no point in comparing apples and oranges and dissing the oranges for not being apples.

    I think Jim's numbers are correct, but I'm a little unclear as to what enclosure he has the 2225's in for his calculations. Is he comparing the loaded A2 enclosure to the specs of the 2225 as a raw driver? I don't recall knowing what your application is, but certainly using the Altec 515's in an Altec combination horn/bass reflex enclosure will be a good match. Personally I think the 2225, like the 515, is a really cool driver for non-VLF bass, and I believe it is spec'ed as suitable for horn loading. Let us know how your comparisons go.

    Scotty has a lot of experience with both JBL and Altec woofers in various enclosures. Maybe he'll chime in here.

  4. #4
    Alex Lancaster
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    I´d like to know where they got 114 dB at 1 watt 1 meter; what frequency band did use?

  5. #5
    RacerXtreme
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    2225 vs. 515

    I have two A2's (with wings) and that may morph into two A1's in the next couple of weeks....





    My question is: will an A1 or A2 system perform better at it's maximum rated power with JBL 2225's or Altec 515's ? I seem to get a lot of conflicting answers. I realize that the 515's were designed for use in a large exponential horn loaded enclosure like the 210, but that doesn't necessarily mean they will out-perform the JBL's in the same cabinet. Wasn't it Mr. James B. Lansing himself that was instrumental in the design and development of the Altec 210 back in the mid 1940's ?

  6. #6
    RIP 2010 scott fitlin's Avatar
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    The 2225 will work, to some degree or another in the Altec 210,s but will not have the midband sensitivity of the Altec 515. Youll get a stronger low end sound from the JBL,s but you will have to work at it to get these drivers to sound right, becuae the 210,s werent really designed for the JBL 2225,s!


    What the 515,s loaded in the 210,s can produce with very little power is amazing, and its the midband sensitivity you will be hearing the most, but the 515,s wont get down real low.

    Everything is a series of compromises and tradeoffs. On one hand, I think you will get a more open and transparent sound from the 515,s, ( this is that realism everyone talks about ) but not nearly as much bass punch as the JBL, and with very little power, BUT, you are kind of limited to 75 watts, as they cant take a whole ton of power! If you like to play bass heavy material, at high SPL,s you might find the 515,s at their limits.

    The JBL 2225,s will take much more power, and will have good bass and mid bass punch, but since you dont have the midband sensitivity of the 515,s vocals and instruments might not sound quite as present, and wont sound as loud because its not as midrangey. OTOH, you might achieve bass definiton with no fear of over excursion, and the JBL is definitely suitable for demanding material!

    Your gonna have to listen to both and see for yourself! Dont be surprised if your totally surprised at how much sound the 515,s can produce with their 75 watts of input though!

    I have some very high efficiency midbass 15,s from 18sound, kind of similar to some of the older bass shy 15,s from the past, 103db@1w@1m, -3db 48hz, and while they do create a seamless image through the midband and into the mid horn, and take very little to drive them, have an openess, they dont have the bass kick, and LF extension, and I always find myself leaning towards the 421-8LF for its heavier bottom sound, and the 421-8LF is no where near as sensitive in the midband as the 18sound, and YOU CAN hear it, but without the bottom, its not totally satisfying to me! So, even though they have the efficiency, its all in the midband, and doesnt sound quite like I expected it to. Without the strong bottom, it is not as full sounding! And playing todays music, I find myself looking for the bottom.

    Im trying some JBL 2226,s and TAD 1603,s in my cabinets with appropriate amps to power them!

    In all fairness the Altec woofers sound great, but I kind of think that for what Im doing, and wanting to REALLY punch the system with todays music, Im always at the physical and electrical limits of the gear.

    Now, I went and put two of the TAD,s into one of my Altec 817,s, and with proper power, its not bad! Bass definition is great! Punchy and growly. No stress, and music through these have a nice sound, tight, yet makes the drum kits have a nice sound. The tradeoff? Slightly more recessed low mid as compared to the Altec woofers! But the low mid is there, and very good image, snares have a very good image, makes me picture a snare drum in my mind! Basslines are articulate. One things for sure, I can PUNCH them, and they can reproduce whatever I want them too, without any stress, or breakup!

    Again, your going to have to listen to both and see for yourself, but for me, I want the full sounding bottom, and through the TAD,s the bass and drums are tight, and do have great definition, and can handle whatever I throw at them.

    With the JBL 2226,s in another cabinet, the bass has a tremendous punch, just like JBL is known for, but the 2226 is a bit too reticent in the low mid for me, the 2225 has better low mid then the 2226 IMHO, but the punch from the JBL,s is incredible!. Like the TAD,s, you gonna have to have considerably higher power than you would need for the 515,s and your gonna hit them harder than the 515,s.

    I do think that physically, the TAD and JBL just handle the low end of todays music better than their Altec counterparts. Its a difference you can hear. But the midrange wont be the same. But, they do some things the Altecs cant handle, too!

    I have to admit, I found that if you work at it, and get things aligned properly, both the JBL and TAD 15,s work much better in Altec basshorns than I thought they would!
    scottyj

  7. #7
    RacerXtreme
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    Scott-

    I agree with you 100 percent. Everything is (or can be) a trade-off. But if I want the low end thump of the JBL's, can't I get some of the midband sensitivity back through a quality comp. driver / horn combination that takes over in that frequency range? I don't know why, but I like the 2360 series horns (2360 short, 2365 med, and 2366 long). A lot of individuals on this site really like 2440 and 2441 JBL compression drivers. Just saw a graph of an Altec 288G and it looked more impressive than the JBL. Obviously you can't go by graphs alone. Some people love this driver and some love that one...... a lot of it is a matter of personal preference.

    I've found that I tend to vary the x-over frequencies somewhat - depending on program material. Sometimes I run the 210's up to 1000 Hz and at other times they get crossed over much lower - maybe down to 200 Hz. But obviously, I'm just playing around trying different things.

    In what frequency range do you think the 210's would be lacking with the 2225's ? If I get two more 210's - which would give me two complete A1 systems, would the low end be adequate even if they were loaded with 515's ? I've heard eight 515's into four 210 cabinets (with wings) and found they were - as you say - somewhat lacking in the thump-thump department.

    Would another four 515's into two more cabinets help ? Maybe the key here is to use JBL's in some cabinets and Altecs in others. Get the heavy stuff from the JBL's and the midband sensitivity from the 515's. The best of both worlds............. Hmmmmm....

    Can you imagine eight 2225's and eight 515's in eight 210 cabinets......... No, that would be way to much for my neighborhood. Four and four?

  8. #8
    RIP 2010 scott fitlin's Avatar
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    I dont think using a comp driver and horn will restore what you dont get from the JBL 2225, the 515 and 2225 just sound different at 250hz, 400hz, etc!

    You could do a combination of one woofer type in one cabinet, and another in another set, but I prefer my sound to be consitent and the same wherever you are, so I am not always a fan of this approach, but it can be done, and is done!

    The 515 does what it was designed to do, and does it well. It just isnt a bottom heavy driver. What I might try to do, is use a high quality boost EQ or parametric to give certain frequencies a gentle nudge, this might help.

    The Altec 288,s! Still have a pair, they have a sound, I loved these, but, I didnt always love the Altec horns! Back in the 70,s when they were in use on 311-90,s we didnt know about doing extra work to damp the horns, and they could ring! again, just like the woofers, its a different sound, Altecs sound.

    In my opinion, the Altec 210,s loaded with JBL 2225,s wont have as prominent a sound from 400hz through 800hz or up, I cross over at 750hz, and this is what I call the more recessed midrange using the TAD or JBL! The Altec woofers just really project the voice, keyboards, and instruments into your listening area! Kind of "Right There In Front of You" type of sound! Altec woofers in Altec horns tend to make recordings sound bigger than they really are, sort of real sounding, this is what they were known for!

    6 of one, half a dozen of the other!
    scottyj

  9. #9
    RacerXtreme
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    compromise

    Would a good compromise be to use the 515's and a single 18" JBL down in the lower part of the cabinet? You'd have midrange / midbass presence and x-tra thump from the big woofer. Do you think the 515's would notice 8 or 9 cubic feet of volume LESS than they have now (if I were to box off the lower part of the cabinet)?

  10. #10
    RIP 2010 scott fitlin's Avatar
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    Quote Originally Posted by RacerXtreme
    Would a good compromise be to use the 515's and a single 18" JBL down in the lower part of the cabinet? You'd have midrange / midbass presence and x-tra thump from the big woofer. Do you think the 515's would notice 8 or 9 cubic feet of volume LESS than they have now (if I were to box off the lower part of the cabinet)?
    Id use 18in subs regardless of what woofer I had in those 210,s! I dont really love the idea of using the lower prat of the 210,s as sub enclosures. Id rather have dedicated subs and cabinets.

    Im not a cabinet tuner, so I dont know how what the 515,s would think of 9cu ft less volume. There are others more qualified to answer that, than me. Im sure it will change the LF response.
    scottyj

  11. #11
    Member hwirt's Avatar
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    Quote Originally Posted by Alex Lancaster
    I´d like to know where they got 114 dB at 1 watt 1 meter; what frequency band did use?
    Found this technical info, the sensitivity is 104dB@1M not 114@1M:

    515-8HHP Architects & Engineers Specification



    The loudspeakers shall be multi-purpose, 15 inch / 381 mm low frequency cone drivers. The loudspeakers shall have an operating bandwidth of 40 Hz to 4 kHz with a sensitivity of 104 dB when measured at a distance of one meter. Their power handling capability shall be 200 watts AES (800 W peak). Their nominal impedance shall be 8 Ohms and 16 Ohms, with a minimum impedance of 7.9 Ohms and 15.8 Ohms at 600 Hz. The magnetic gap of these drivers shall have a flux density of 1.5 T, resulting from an 8.25 lbs. (3.74 kg) ferrite magnet. Their nominal free-air cone resonance shall be 37 Hz and their voice-coil shall be 3 inches (76 mm) in diameter of edge-wound aluminum ribbon. The loudspeakers shall have dimensions of 16 inches (406 mm) in diameter and 6.69 inches (170 mm) in depth, and shall weigh 30 lbs. (13.6 kg). The low frequency loudspeakers shall be Altec Lansing models 515-8HHP and 515-16HHP.

  12. #12
    RIP 2011 Zilch's Avatar
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    So, he's comparing an A2 loaded with 4 ea. mutually coupled 104 dB Altec 515 drivers with a single 98 dB 2225H?

    That's fair.

    Seems to me the difference is 6 dB....

  13. #13
    RIP 2010 scott fitlin's Avatar
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    It is fair, but, at what frequency do the 515-8GHP,s have 104db sensitivity?
    scottyj

  14. #14
    Senior Member CONVERGENCE's Avatar
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    Voice Coil

    Hi Racer Extreme,
    quote:
    "Can someone explain to me the difference between overhung and underhung voice coils. "

    A coil is usually either two or four layers of copper wire. Some coils are short and are about the length of the width of the front plate, or gap. These are called even hung, or under hung voice coils. A coil that is longer than the thickness of the front plate is called an over hung coil. The underhung coil is more efficient (louder for given input signal), but reaches it limit sooner than a longer coil. An over hung coil isn't as efficient as an under hung coil, but can travel farther before reaching its limit.

  15. #15
    Senior Member hmolwitz's Avatar
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    Altec specs

    Altec specs those were for a single woofer, as far as I can tell those drivers are not made for the low bass, and neither are the cabs designed for them. If that is what you are looking for you should build this.

    I know there is a better way to put in a link here, sorry.
    http://audioheritage.org/vbulletin/s...+Bandpass+dual

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