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Driver swap.. Can I do this??

Discussion in 'Amps and Cabs [BG]' started by ::::BASSIST::::, Jan 11, 2005.


  1. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    The ampeg pb-110 has a speaker sensitivity of 93db. If i find its not loud enough could I simply replace the speaker with another bass guitar speaker with a higher sensitivity rating (say 97db) for increased volume?

    Should work right?
     
  2. Happy MurphDay

    Happy MurphDay

    Mar 9, 2004
    around
    yes, however, check the specs and see how much space the new driver needs and the space the cab is, and if it is ported or not
     
  3. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    I believe that the Portabass cabinets are sealed. I know that they have a 4 ohm impedance.

    As Happy Murphday mentioned, chose a new speaker carefully...if the new one wants more cabinet volume, you'll have limited low end. You can plug the Thiele-Small parameters into WinISD or ISD online and plot a curve of the low end response. http://www.linearteam.dk
     
  4. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    I see where you're coming from cause that's pretty poor, but changing speakers in an amp/cab can be like changing pups in a bass in terms of tone. Myself, I'd call or email ampeg and see what they had to say about it. I just read something recently along these lines but can't recall what it was but seems there was a reason lower efficiency speakers are more desireable in some designs.
     
  5. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    I looked at ISD online calculator, but i have no idea what any of the terminology means :meh:

    I tried to email ampeg but they dont have an email address.

    I know that the ampeg cab is 15x15x12 and is not ported but has a horn. The current drivers magnet weight is 4.7 ounces.

    Frequency Response (-3dB): 40 Hz - 20 kHz

    Neodymium Magnet Weight: 4 oz

    any more suggestions?

    :confused: :) :cool:
     
  6. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The average high sensitivity 12 is not going to put out any more in the low frequencies (100 Hz and below) than your present driver as the box is simply too small. A bigger sound will require not only a better driver but also a bigger and/or better box to put it in.
     
  7. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    well the Flite 110 is 13x13x12 with a driver which is 97db so i am sure it would be somewhat louder even though the box is actually smaller. If i could get my hands on a Flite 10" driver or something similar with a higher sensitivity it should be louder should it not?
     
  8. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    If you start looking around at drivers, chances are that the Thiele-Small parameters will be published along side of the description. If you look at the left hand column on ISD online you only need to input three parameters...Vas (which relates to the loudspeaker's stiffness...sort of), Fs which is the free-air resonance and Qts which is the total Q or quality factor. All of these properties can be measured and calculated, but loudspeaker mfrs are sweethearts by providing the data to we arm-chair loudspeaker enclosure designers.

    The other quantity that you need to enter is the internal volume of the enclosure, in liters. There are 62.5 cubic inches in a liter so if you multiply the inside length, width and depth of the enclosure and then divide by 62.5 you'll get the volume in liters.

    Once you enter those four numbers (three that you look up for the speaker you're considering and the enclosure volume that you calculate) simply push the "Draw It" button. You will be rewarded with a plot of the calculated frequency response of the speaker under consideration in the Ampeg box.

    Once you go though the motions, it shouldn't seem so unfamiliar.

    Please feel free to ask if you have any questions, or need help.

    BTW, -3dB at 40 Hz for a 10 in. speaker is pretty good...
     
  9. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    Technically yes but 4 Ohm 10" speakers with high sensitivity are extremely rare. Most of the 4 Ohm 10's are low sensitivity subs designed for Home or Car Hi Fi, and most don't do anything above 300Hz. they're no good to you.

    The high sensitivity 10's are usually 8 ohms, so you'll end up with a wattage drop that may or may not cancel out the extra volume you're trying to generate.

    I say sell it and start looking for a new cab.
     
  10. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    FWIW:

    never had a reason to contact Ampeg but some manufacturers don't have email addresses (or ones that work in some cases). Then there should be a number you can call. Seems I recall people stating they've contacted them. Probably something you want to know anyway cause if you have some of their equipment, you may need to contact them someday.
     
  11. Let's put yourself in Ampeg's shoes here. You've designed an enclosure, tested it, and marketed it. Now somebody comes along and says "hey I don't like what you did. Give me some free help, changing this to something different"

    I know how I'd respond if I worked at Ampeg. :rolleyes:
     
  12. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Reasonable enough to assume. On the other hand, they may say something that's worth a call. If nothing else, you find out how they treat you - and that to me is worth a call.
     
  13. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    If everybody just accepted the status quo where would we be?

    I personally don't find it objectionable in the least to challenge a corporation to make a better product or modify their product for increased effeciency.

    Just my $.02
     
  14. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    Hey, thanks for your assistance! :)
     
  15. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The bottom line is that there's no free lunch. Higher sensitivity drivers tend to get that higher sensitivity by having higher fs and lower Qts values, both of which reduce bass response. SPL values are broadband averages and don't tell you what the driver is doing in the bass range. If you loaded that box with a 101dB/watt EVM12L you'd find that it would have almost no output at 60 Hz. The SPL figure by itself tells you very little.
     
  16. luknfur

    luknfur

    Jan 14, 2004
    DIXIE
    Yeh, that sounds along the lines of what I ran across. It's been a while since I've messed with speakers, and they were all 15's. I've had Altecs, Klipsch, JBL's among others and most of their SPL's were around 100 give or take a bit, the lowest 98 I think. Don't remember exactly but every increase in SPL is like doubling amp wattage or something that extreme. So I'm inclined to believe a speaker with an SPL as low as 93 is there by design. Louder is not better if tone is trashed in the process. There are ways to get volume if you can find a tone worth amplifiying.
     
  17. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    On the ampeg site there are email and phone (toll-free) contacts for the service department, who provide the main user support.

    It's not quite that bad, but please forgive us if we don't provide our engineering data or free engineering services outside of supporting the products we sell, as-sold.....And, officially, we don't support modifications aside from upgrades that bring the unit to equal a current production unit.

    This is due to the lawyers and the possibility of damage suits if we give out a "mod" that is subsequently improperly done, or applied to the wrong unit, etc, etc. We can't control that, so we must avoid it. I know it sometimes leads to silly situations, but otherwise we can get into serious trouble.

    We do have some speakers for the dual speaker PB cabinets which have similar performance and several dB more output. We are actually using these newer versions in current production.

    However, we don't have anything at the impedance of the single speaker PB-110 cabinet (4 ohms). If you used the new type speaker as a single speaker, much of the improvement might be nullified by the impedance change.
     
  18. ::::BASSIST::::

    ::::BASSIST:::: Progress Not Perfection.

    Sep 2, 2004
    Vancouver, BC Canada
    Interesting. I'll keep what you guys are saying mind.

    Here is what Chuck said at Eminence, "The DeltaLite 2510 has an average sensitivity of about 96.1 dB. I think they will work great for you. "

    Maybe he is not factoring in the variables discussed in this thread. However, the Deltalite 2510 is 8ohms, and as a TBer previously discussed, that might not give me much more vol. because the ampeg driver is 4ohms and gets more out of the amp.

    I used the SPL calculator with the variables of 20 feet distance from speaker and only 1 speaker. the results were:

    -the deltalite 2510 @140 watts and 96.1 sensitivity gave 101.9db

    -the ampeg driver @220 watts and 93 sensitivity gave 100.7db

    if i could try out a 4ohm speaker with higher sensitivity and see how it sounds in terms of tone that would be ideal.
     
  19. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    There it is.....the 96 dB sensitivity is only 3 dB more, and the difference due to impedance is also 3 dB.

    The extra dB difference shown is partly due to the power not completely doubling. In any case, it is within what I would call "normal error", as I don't trust ANY ordinary acoustic sensitivity measurement down to 1 dB.
     
  20. Petebass

    Petebass

    Dec 22, 2002
    QLD Australia
    From memory, it also likes a cab that's twice as large as the one you've got. He forgot to mention that.

    The only way I can see it working is if you consider buying 2 of them and make it into an Isobaric cab. It halves the cab size, gives you your 4 ohm load, maintains your 96dB sensitivity, and doubles the price tag. You would then have to port the cab............

    I'd wait to see how Ampegs testing goes.