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SPL…what manufacturers don’t tell you

Discussion in 'Amps and Cabs [BG]' started by oldfclefer, Jul 2, 2014.

  1. oldfclefer

    oldfclefer low ended

    May 5, 2005
    Southern Ohio
    After just a few recent posts on this forum…I’ve been told that I’m wrong about my amp knowledge enough times that I decided to do some research…and find out the source of the misinformation I seem to be repeating…
    One thread asked if a particular set of speakers would work with a particular amplifier…I replied that based on the specs the OP provided that the rig would work if the OP was careful with volume…and my reply was set upon by a number of TB “experts” telling me how wrong I was…I posted links to reputable cabinet makers stating the exact premises that I based my reply upon…but the “experts” continued to denigrate my response…so I backed off and did some research…seeking out the most current knowledge and theories surrounding the subject of speaker cabinet capability…
    All manufacturers publish the "wattage" ratings of their cabs...that's universal...almost all publish at least peak rating...the rest is size, weight, materials, and size and type of drivers...that's all useful...but it doesn't tell you how loud the cabinet can get...
    What I found was that the spec “SPL” (Sound Pressure Level) was the most accurate spec available that measures a given speaker cabinet’s mechanical ability to reproduce a bass signal…according to Eminence this spec can also be stated as “Sensitivity”…
    Both SPL and Sensitivity are measured in “DB” or decibels…which states a driver’s ability to move air…in other words, SPL tells you how loud a cabinet can get…
    So I thought okay, this is good…here is a spec anyone can use to determine the efficiency of any cabinet…which is especially useful when shopping for new gear…
    Here’s the problem: of the 24 manufacturers whose sales literature I checked, only 5 offered SPL as a spec…and only 8 offered Sensitivity as a spec…
    Here’s a list who offer those specs:
    SPL – Ampeg, Peavey, Markbass, Warwick, Eden
    Sensitivity – Ampeg, Hartke, Agular, Genz Benz, Epiphani, Phil Jones, Carvin, EBS
    And Here’s a list of those who offer neither spec:
    GK, Fender, Traynor, Mesa, Acoustic, TC Electronic, Orange, Ashdown, Line 6, Bugera, Trace Eliot, Ibanez
    I know I’ve missed a few, but I believe there’s enough here to show a decent cross section…it appears that about 50% of manufacturers don’t feel that cabinet efficiency is all that important to a potential buyer…maybe the specs show up in their owner’s manuals, but if I’m looking for a cab, I usually don’t get that deep into it…I was surprised that some, like Mesa and GK, didn’t publish SPL for their cabs…so I dug a little farther into their web sites and still came up empty…
    So do I limit myself to the ones that publish SPL?...not me…this only illustrates to me that not much has changed since the old days…the best bet is to go to a store and try out gear before I plunk down cash…I even bring my own bass and amp head if I’m buying a cab….that’s the only way I’ll know for sure what will work for me…
    moe.moe likes this.
  2. Considering none of them tell you how they measure any of those specs, they are all useless.

    Good lookin' out though!
    obimark, T-Bird and maestrovert like this.
  3. Plucky The Bassist

    Plucky The Bassist ZOMG! I'm back from the dead!

    Jul 30, 2010
    Houston, TX
    From Musiciansfriend.com (http://www.musiciansfriend.com/amplifiers-effects/gallien-krueger-neo-412-4x12-bass-speaker-cabinet)

    Neo 412 4x12 Bass Speaker Cabinet Specifications:

    • RMS power handling: 1200W
    • Peak power handling: 2400W
    • 4 ohms
    • Sensitivity: 102 dB
    • Maximum SPL: 133 dB
    • Frequency response (-3dB): 54Hz - 19kHz
    • Front-ported
    • 99 lb.
    • 26"W x 41"H x 17"D

    Gotta dig a little harder sometimes! They might not have them listed on the site, but sometimes they want to make the sites more simplistic and give the dirty deets to the retailers. CL400 makes a good point too, they could just toss out numbers and use very flawed methods to conjure them.
  4. silky smoove

    silky smoove Supporting Member

    May 19, 2004
    Seattle, WA
    Don't bother basing purchases around specs. Go try out the cab in question with your amp and your bass. Do you like it? Do you not like it? That's all that matters.
    4-stringB, obimark, scotch and 2 others like this.
  5. GK lists the specs in their manuals.
    SunnBass likes this.
  6. callofcthulhu


    Oct 16, 2012
    Don't know why you wouldn't look at the owner's manual for something you were thinking of buying, that's usually the first place I look.
  7. As consumers, why should we have to dig that deep?
    squidtastic and oldfclefer like this.
  8. oldfclefer

    oldfclefer low ended

    May 5, 2005
    Southern Ohio
  9. It doesnt matter where the specs are posted:

    The playing field isnt level. As an example, the vast majority of manufactures list a power rating. This is a thermal power rating taken somewhere around 1kHz. Useless for telling you how much power it can handle in the bass frequency before fart out.
  10. Fat Steve

    Fat Steve The poodle bites, the poodle chews it.

    I can't answer for everybody, but as a consumer with limited means, I always look not only in the owners manual, but also at every review and write up I can get my hand on. It's my contention that, as a consumer, the onus is on us to ensure that the product we purchase is the product we need. The manufacturer is naturally going to stack the chips in their favor, being that they run a profit driven enterprise and will tend to obfuscate the data released to try and appeal to a more broad segment of the consumer base. If I'm going to purchase a product on specs alone, I better damn well understand what metric those specs are representing.
  11. oldfclefer

    oldfclefer low ended

    May 5, 2005
    Southern Ohio
    Well if you're buying strictly off of the internet, you might buy on specs alone...for me...specs are just a point of reference to narrow my search...I'm still going to find what I need locally and try it first to see if it lives up to those specs and whatever other claims the manufacturer makes...
  12. How do you test sensitivity and power handling on your own?
  13. Bassamatic

    Bassamatic keepin' the beat since the 60's Supporting Member

    You are very correct that these are very important specs. Perhaps the ones that are not shown are not very good and they want to hide them?? For sure the maker knows what they are.

    Efficiency of a speaker is much more important than the power of your amp. Why?

    Doubling the electrical power (Watts) of an amp only gets you 0.7 dB of Acoustic power (SPL). It takes TEN times the amp power to cause double the acoustic power. (hard to understand, but easy enough to test).

    On the other hand - doubling the efficiency of a speaker (+3dB) DOUBLES your SPL, since they are both measuring and rating the same thing - acoustic power.

    If you are concerned about the output and your amp size, a difference in efficiency between two cabs of just a few dB can make a huge difference.

    Just FYI - Speaker efficiency is commonly measured as 1W input @ 1 Meter distance, 1 KHz signal. However, this may not be very valid for us bass players, as most of our energy is well below 1 kHz. Perhaps there should be a new efficiency spec for bass and subwoofer speakers.

    Edit - hard to test on your own with out a signal generator, wattmeter, acoustic test room and a calibrated SPL meter.
    punchdrunk and Garret Graves like this.
  14. RoadRanger

    RoadRanger Supporting Member

    Feb 18, 2004
    NE CT
    Max SPL is usually at some frequency like 100 Hz and tells you nothing about the output at the fundamental of the "E" or "B" string which is usually limited by the maximum displacement NOT the power rating of the drivers.
  15. ArtechnikA

    ArtechnikA I endorsed a check once... Gold Supporting Member

    Feb 24, 2013
    This little tidbit was pretty hard to find - embedded as it was inside another quote you had to expand to find.
    I would love to hear about the research methodology that led you to this conclusion; of everything I've heard about 1x15's, "most popular" isn't very far up the list...
  16. ggoat!!!

    ggoat!!! Banned

    Apr 6, 2008
    Anyone who is obsessed with wattage produced by amplifiers but who doesn't take the time to understand that it takes DOUBLE the wattage to produce a measley 3db in increased volume is completely ignorant...no offense meant. A buyer should always know what they are buying and should thoroughly research what they are trying to accomplish.

    You can increase your volume by either drastically increasing wattage or merely switching to more efficient drivers or cabinets. Old Peavey Black Widow 1502DT drivers were well known for massive efficiency and that's why a 210 watt solid state Peavey back in the 80's would overpower the entire band before the DDT light came on...it wasn't the amount of wattage of the amp, it was the super-efficiency of those 15" 1502 Black Widows making the most of every watt. And, Peavey made even MORE efficient versions of the Black Widow, although they were voiced for more midrange (to be used in PAs) although they work great for a 70's mid-heavy Geddy Lee-ish tone. The aluminum-domed shallow baskets of the early 80's exhibit more cone cry and are more colored and vowel-like; these qualities are looked down upon nowadays, but back then when people had unique identifiable less invisible bass tones things like color and character were highly regarded...as well as efficiency.
    Last edited: Jul 2, 2014
    maestrovert likes this.
  17. 3db is nothing to sneeze at. Logarithmic scale and all.
    eukatheude, Geri O and maestrovert like this.
  18. DukeLeJeune

    DukeLeJeune rational romantic mystic cynical idealist Supporting Member Commercial User

    Nov 24, 2008
    Princeton, Texas
    Owner & designer, AudioKinesis; Auth. mfg, Big E (Home Audio only)
    A doubling of power input results in a 3 dB increase in output, assuming we don't have any other limiting factors (fartout, thermal compression).
    mrmills, goran and Downunderwonder like this.
  19. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    I would suggest, if manufacturers were listening, that Spl and Xmax (within the enclosure, not just of the speaker), as well as Watts be the FIRST three listed specs of a cabinet. Will it happen? No. I am willing to fork over my Win ISD plots for these. And AFAIK all the boutique guys you'll find here are more than happy to give you any info you'll ask for. Big brand box makers aren't so forthcoming, as a rule (with exceptions). Likely because they know well that their cabs will turn into fartboxes at HALF or even less power than they can get away with rating them at. It doesn't mean they're thieves; and most of them make good products. It's just that there really isn't a standard way to predict what a box will do with YOUR tone settings, and EVERY amp.
    oldfclefer likes this.
  20. As do I, but these specs should be front & centre when buying a product. Much like when buying a PC you expect to see the Processor, RAM, Video card & Hard drive stats, to some degree.

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