Speaker cabinet sensitivity : relevant?

Discussion in 'Amps [BG]' started by SilkyStrings, Nov 26, 2012.


  1. SilkyStrings

    SilkyStrings

    Joined:
    Aug 27, 2006
    Messages:
    105
    Location:
    Los Angeles, CA
    I've been looking at some specs on the newer speaker cabinets, since I'm considering a cabinet upgrade at the moment. I have noticed that Aguilar's newer DB112 cabinet is rated at 95dB, versus 102dB for the older GS112. From my rudimentary understanding this means that the older GS series cab will be at least twice as loud as the DB series cab given the same power output from the amp due to it's higher sensitivity. I love having headroom so is there something I'm missing here?

    Using my Aguilar Th-500 won't I be giving up some volume going with the newer DB112 cabinets, or is this difference just due to front porting versus rear porting?

    I'm very curious about this.
     
  2. KJung

    KJung

    Joined:
    Apr 9, 2005
    Messages:
    44,517
    Location:
    Wisconsin and Upper Michigan
    Unfortunately, those published spec's are pretty worthless. Most of the sensitivity specs are based on the upper midrange (1K), and are more a measure of the brightness of the cab up top than anything else.

    The DB cabs (which use the same drivers as the GS cabs), are tuned to enhance the mid mid response a bit, and to my ear, are actually 'louder per watt' since the human ear is more sensitive to midrange.

    Location of ports means very little.

    IMO!
     
  3. Mr. Foxen

    Mr. Foxen

    Joined:
    Jul 24, 2009
    Messages:
    3,555
    Location:
    Bristol, UK
    Disclosures:
    Amp tinkerer at Ampstack
    Manufacturers quoted specs can be a bit dodge. I think Aguilar revised theirs, so you might have a pre and post revision comparison there. I think AlexClaber of Barefaced called them out about it, then they revised. 102db is pretty unrealistic for the GS112, since that would make it louder than an SVT 8x10 on its own (Based on their site, which BFM has said is pretty straight up on specs).
     
  4. SilkyStrings

    SilkyStrings

    Joined:
    Aug 27, 2006
    Messages:
    105
    Location:
    Los Angeles, CA
    OK thanks for clearing that up. I feel better now!
     
  5. Register to disable this ad
  6. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Messages:
    79,958
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps, EMG Pickups
    Ya, don't worry about raw numbers unless there is actually some meaningful context.
     
  7. bgavin

    bgavin Supporting Member

    Joined:
    May 3, 2001
    Messages:
    6,137
    Location:
    Orangevale, CA 95662
    A charts beats printed specs every time.
    If no chart is available, the spec should tell you the average dB sensitivity, the range where it is valid, and the size of the range.

    95 SPL, +/- 3dB, 60 Hz to 15,000 Hz.

    This means you will have a swing of 6dB max, within the 60~15K range.
    Most cab makers choose to (lie by omission) and use 10dB, or 20dB total swing.
    They call this "usable range" or some such.

    Another possibility is they are outright lying. Then all bets are off.
    They can measure the cab in a corner, and this will give a big boost to the chart compared to center stage or outdoors.
    With so many creative ways to lie ...er 'exaggerate', you'd think Congress wrote the specs.
     
  8. SilkyStrings

    SilkyStrings

    Joined:
    Aug 27, 2006
    Messages:
    105
    Location:
    Los Angeles, CA
    Actually just checked the Aguilar website, they do indeed now show the GS112 as 95dB samee as the DB112. Interestingly the SL112 is showing 99.9dB, which seems high, perhaps this cab is more mid forward?

    I'm guessing the DB or SL cabs are a better match for my TH500 since most have suggested the TH500 liking a tighter low end cabinet, or is this just about the trendiness of the 'old school' look in the newer designs?
     
  9. BogeyBass

    BogeyBass

    Joined:
    Sep 14, 2010
    Messages:
    1,478
    Sensitivity is relevant, and yes your on the right track looking for the highest SPL.

    But as mentioned manufactures ratings can be very overrated.

    Most common used single 12" speakers wont do more than average of 94 to 97 dB.

    And yes if you look at a response chart of any speaker there wil be a huge peak at the top end of the response. Usually this peak occurs where the speaker will start to have a phase shift and will also be where the beaming frequencies appear. So pretty much worthless in the bass frequency range.
    So yes its great if the speaker does have good highend, but this is also where off axis response is getting poor, so again its meaningless in trying to judge sensitivity. Below 1000hz is where it counts. and the reall meat is below 600hz

    So speaker manufactures and cabinet builders love to use the higher peaks to make the average response look higher than it really is.

    Aguilar claims 99.9 dB sensitivity and claims a 7oz neo magnet
    Really Really smells like a Eminence Deltalite 11 2512

    Aguilar is most likely trying to be a little more honest with rating and decided to use the driver manufactures rated number to try and stay out of to much trouble. In this case 99.9 dB
    Which has been gracefully averaged higher by them as well.

    But if you look at response chart of the 2512 you will see below 1000hz sensitivity is about 98dB and below 300hz it drops down to 96dB which is actually pretty good for a 12" most of them are much lower average around 94 to 95dB below 1000hz

    If you load that driver into a modeling program it shows the average SPL to be 96.9 dB which is much more realistic number when your actually talking about lower frequency performance and where the bass guitar actually is. And its not a biased number coming from a manufacture. Its based on the actual Mechanical and Electrical measurements of the driver
     
  10. ThisBass

    ThisBass

    Joined:
    Aug 29, 2012
    Messages:
    863
    Location:
    Germany
    +1 :bassist:

    There are many different drivers out there with less moving mass and higher fs and therefore excellent efficiency (which is SPL). Trying do give a cab's response a strongly low response impacts the efficiency as well down to lower values.

    If someone likes to deal with a response point of 65..70Hz (which is pretty enough for a 4-string bass) then it is possible to achieve excellent efficiency.
    There are some drivers out there like the legendary EV 12L with an efficiency of nearly 100dB but, some lack of response at the bottom.
     
  11. SilkyStrings

    SilkyStrings

    Joined:
    Aug 27, 2006
    Messages:
    105
    Location:
    Los Angeles, CA
    I imagine two cabs together also increases this efficiency?

    I'm also wondering if a good 4x10 cab will out perform a pair of these newer 12's such as Genz Benz, Aguilar, etc. There is another thread on here about this, in other words will a pair of twelves be a compromise, I'll have to go back and re-read it.

    No shortage of options out there but my choice has to fit in my car!
     
  12. JimmyM

    JimmyM Supporting Member

    Joined:
    Apr 11, 2005
    Messages:
    79,958
    Location:
    Apopka, FL
    Disclosures:
    Endorsing: Ampeg Amps, EMG Pickups
    That was my impression of the SL112 as opposed to the DB410 they had on the floor at Sam Ash a couple months ago.
     
  13. ThisBass

    ThisBass

    Joined:
    Aug 29, 2012
    Messages:
    863
    Location:
    Germany
    ...should be a EVM 12L driver which is indeed mid forward and with an efficiency of 100 dB but, with a response not lower then 70Hz.
     
  14. BogeyBass

    BogeyBass

    Joined:
    Sep 14, 2010
    Messages:
    1,478
    yes doubling of speaker area will increase sensitivity by 3dB

    So a single 12 would be 96dB
    and a 2x12 would be 99dB
    and a 4x12 would be 102dB
    and a 8x12 would be 105dB

    and I highly recommend using a minimum of 2 drivers

    it is why my opinion is a 2x12 or 2x15
    would satisfy almost 80% of all bass players

    which gives decent power handling and average sensitivity
    of 99 to 101 dB

    10" speakers lack sensitivity a 4x10 only hits 97 to 98 dB
    plus the dispersion is lacking

    A vertical 2x12 could perform similar or equal to a 4x10
    but a 2x12 could have more lowend and depending on driver used actually have more highend than a 10". Plus being a vertical alignment will offer more off axis response. Which is beneficial to the player and band members. Plus a higher stack offers better monitoring on stage for the player simply because its closer to ear level.

    Keep in mind there is many lowcost 2x12 cabinets that would never keep up with a 4x10. But a high quality 2x12 with 5mm or higher xmax would do just fine.

    The only real drawback to stacking single high quality 12's
    is the cost is higher.

    Otherwise single 15's are not much larger, but offer the highest
    sensitivity. average 15 is 97 to 99dB
    so a pair of 15's is the best bang for the buck for having a portable system with good sensitivity and needing less power.

    People tend to laugh at 200 to 250 watt heads, but its really all you need with a efficient speaker system.
    Even at that a overdriven 150 watt tube head will have alot of presence in a band.

    Just goes to show when JBL came out with 5mm drivers with better thermal ratings. A 2x15 cabinet loaded with K-140's
    could still make 80% of bass players happy.
    And the more robust fullrange neo speakers of the day dont really go much beyond 5mm. they are just lighter.

    So Sunn and Fender figured this krap out over 40 years ago with there 2x15 cabinets
    you just had to be able to afford the upgrade speakers offered by Fender or the standard speakers offered by Sunn.

    maybe the weight is the only limit, but modern neos and cabinet design has fixed that. Single 12's or 15's should fit in just about any car.
     
  15. agedhorse

    agedhorse Development Engineer-Mesa, Product Support-Genz Supporting Member

    Joined:
    Feb 12, 2006
    Messages:
    5,361
    Note that this is only close to true below a critical frequency that depends on the driver spacing. Most of this coupling occurs below a couple hundred Hz on a 12" driver, primarily where the efficiency begins to suffer from loss of boundery. The coupling ratio also decreases with each doubling of drivers, otherwise you would exceed 100% efficiency once you get past the ~7th or 8th doubling. At that point the simplified calculations begin to look like a perpetual motion machine... attractive to marketers but not to engineers ;)

    I believe (from memory) that somewhere around 112dB/1W/1M is about 100% electrical to acoustic power transform. This is for an omnidirectional of full space source radiator. Perhaps somebody who does this every day could comment in more detail?
     
  16. BogeyBass

    BogeyBass

    Joined:
    Sep 14, 2010
    Messages:
    1,478
    Yes Sir of course AgedHorse

    I was just showing basic numbers to show that adding more speakers increases sensitivity.

    But of course many variables like coupling, temperature ,humidity
    room gain, cabinet volume, wind and how many beers you drank can effect actual real world sensitivity.

    but I do feel alcohol has a large effect on my sensitivity
    or even how many blonds are standing in the same room.
     
  17. agedhorse

    agedhorse Development Engineer-Mesa, Product Support-Genz Supporting Member

    Joined:
    Feb 12, 2006
    Messages:
    5,361
    Alcohol modified sensitivity is something that I try to avoid at all costs. Nothing like being in monitor world when things come apart on stage for this reason!
     
  18. bgavin

    bgavin Supporting Member

    Joined:
    May 3, 2001
    Messages:
    6,137
    Location:
    Orangevale, CA 95662
  19. OtisRocks

    OtisRocks

    Joined:
    Oct 28, 2009
    Messages:
    88
    Location:
    Toronto
    According to this online calculator your memory is 100% correct.
     
  20. jungleheat

    jungleheat Banned

    Joined:
    Jun 19, 2011
    Messages:
    968
    Location:
    DC
    Sensitivity is probably MORE important than power handling and amp power rating. You can have a range of 15+ db of sensitivity between different speakers/cabs. That's the equivalent of having 32 times more power. But more sensitive speakers aren't necessarily proportionally more expensive in terms of their respective power equivalency.

    So if you have 2 102db JBL 15s in a cab for 105db at 1w/1m, and a 96db 4x10, you can get the same volume out of 100w that you could with 400 from the 4x10.
     
  21. agedhorse

    agedhorse Development Engineer-Mesa, Product Support-Genz Supporting Member

    Joined:
    Feb 12, 2006
    Messages:
    5,361
    Good grief, I haven't lost my mind???:bag:

    Something else to note is that while the raw sensitivity number may be important, it's also important to know how this number is derived. Things like measured bandwidth, boundery conditions and at what power level the number is normalized to all factor into the real world sensitivity.
     

Share This Page