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+/-3dB @41 HZ and cabs that are rated at it

Discussion in 'Amps and Cabs [BG]' started by chiplexic, May 26, 2004.

  1. chiplexic


    Apr 21, 2004
    +/-3 db is what I look for in determining a cabs ability in lower end. But that's all it is to me is a spec. A line in the sand if you will. So can anybody tell me just what +/-3 decibles is refering to. I know it is usually written - or +/- 3 db 41hz-16khz for instance. 41hz being the low end ability and 16khz being the high end ability.
    It appeals to me as a spec because I want to get the best true lowE spectrum I can in a "traditional" cab . I say traditional because I know Acme LowB and other low efficientce cabs can do better but I want to find the best in a traditional efficientce set up that doesn't require a 1000watts of amp as well.

    So in simplest terms language what is 3db and what makes other than Eden have a cab rated at 41 hz at or below +/-3 dB ?
  2. Ericman197


    Feb 23, 2004
    In laymen's terms, it means that the cab is going to be noticably louder or less loud at that frequency. If a cab had +/-2dB over a range of say, 41Hz to 20Hz, it'd have a very smooth and hi-fi sound. However, this is not always the case... manufacturers will usually exaggerate the statistics and use their own little tricks.

    By the statistics, most Eden cabs should be very hi-fi... however, we know that's not really the case. If a manufacturer was very honest, he would say something such as -6dB at 45Hz, +/-3dB 60~2kHz, +/-6dB 2kHz~10kHz, +/- 3dB 10kHz~15kHz, -6dB at 18kHz.

    I made up those statistics... they could be much more complex, or much less so. The fact of the matter is that most cabs will exhibit several peaks and valleys, oftentimes in excess of 3dB. Most manufacturers will simply use the +/- 3dB from X to X to refer to the low and high end but not the midrange.

    Unfortunately, you'd really need to try out the cab to determine it's sound quality. The +/- statistics will give you a good idea of the low and high end capabilities, but the low end is the most important... almost any decent tweeter will give you the high end you need. Most manufacturers will lie on the low end capabilities, so all in all the statistics are meaningless. You really have to try the cabs out for yourself... oftentimes a cab with a relatively shallow rating, such as -10dB @ 55Hz, will have a very deep perceived sound. The human ear is a very complex thing...
  3. The Acme is it.

    If you want low frequency extension plus high efficiency, the 3rd parameter must be a very large cabinet. Since this is impractical, the tradeoff is a small cabinet at a cost of low efficiency (Acme). You cannot have it all in one cabinet... there is no free lunch in physics.

    As for -3dB at 41 Hz... unless the cabinet maker publishes his measurement graphs (like Phil Jones does), it is usually nothing more than marketing bullsh!t. This is why an audition is so important, especially an audition in a typical venue. They sound quite a bit different than a music store.
  4. alexclaber

    alexclaber Commercial User

    Jun 19, 2001
    Brighton, UK
    Director - Barefaced Ltd
    How large would that be? Is it volume per driver or total volume that counts?


  5. "Large" would be 6-10 cu.ft... Refrigerator style. Be it due to multiple small drivers needing little space each or one very large driver needing a very large box on its own.

    Like bgavin said, if you want loud, deep bass, you either have to pump a few kilowatt into the cab, or haul a fridge. If you want it all: loud, deep, small, better bring considerable amounts of cash ;)
  6. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA

    Amen to that bgavin. Couldn't have said it better myself.

    It's an excellent sign when a cabinet maker (like Phil Jones) publishes actual SPL graphs, "and" publishes the method by which the measurements were made. Manufacturers who make claims like -3db at 41 Hz and 16 kHz generally don't say how they arrived at those figures, or what the response looks like anywhere in between. And they generally don't publish their measurement methods either, which invariably makes me suspicious.

    For the meaning of dB and such, I recommend checking out the Audio Cyclopedia, there is an entire chapter devoted to measurements and what they mean. These days everyone and their brother is trying to out-do each other with their 3 dB-down points, but again bgavin is right on the money, most of the time it's just marketing b-word and has little or no relevance in real life. Also pay careful attention to the "scales" when you're looking at graphs like Phil Jones'. For instance his charts show a 20 dB drop below 150 Hz, which looks pretty bad, but in reality this is pretty impressive for a bass cab, when you're measuring SPL at a distance with a microphone. I just have to laugh when I read "3 dB down at 35 Hz" in relation to a 10" cab, one would think they'd stuck a piezo right up inside the voice coil or something. There's not a 10" speaker in the universe with that kind of low frequency response. Not even in a perfectly tuned cab. Take one of those cabs outdoors and you'll hear exactly what it sounds like. Yuk yuk. :)
  7. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    Fremont, Ohio
    Editor-in-Chief, Bass Gear Magazine
    Looking at a spreadsheet of cabs that I had prepared a while back, here are the cabs that I show as being rated down to at least 41Hz:

    Accugroove Tri 208 (35Hz)
    Accugroove Tri 112 (39Hz)
    Accugroove Mini Whappo (41Hz)
    Accugroove Whappo, Jr. (39Hz)
    Accugroove Bill Dickens 2x12 (33Hz)
    Accugroove El Whappo (35Hz)
    Aguilar GS 212 (41Hz)
    Bergantino HT210 (36Hz)
    Bergantino HT322 (39Hz)
    Eden D-112XLT (36Hz)
    Eden D-210XST (30Hz)
    Eden CXM-110 (36Hz)
    Epifani T-210 (40Hz)
    Epifani T-212 (38Hz)
    Epifani T-212D (40Hz)
    Epifani T-310 (40Hz)
    EA CxL-112 (38Hz)
    EA CX/VL-310 (39Hz)
    EA VL-210 (38Hz)
    EA VL-208 (40Hz)
    EA VL-110 (41Hz)
    Raezer's Edge Bass 12 (40Hz)

    This list is not exhaustive, and is at least one year out of date, but hopefullly, it is of some use.

  8. In the beginning of your post you praise Bruce with an "Amen" and then go on to counter his post (and a lot of my own) with a statement like this. Looking at the PJB designs you can see that excellent specs are coming out of a bunch of 5s. Real world reports on his cabs would suggest that they perform as well as his specs would suggest. So, there are indeed 10" drivers (and smaller) with excellent low frequency response. Stick four (or more) of them in a properly tuned box and you'll have cabs like the Acme Low B-4 or PJB Piranha that will sonically out-perform a lot of 15s and 18s, the trade-off usually being efficiency.

    BTW- Tom... thanks for the list!
  9. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Did you look at the Phil Jones charts? 20 dB down from 150 Hz is not the same as 3dB down at 41 Hz. Better take another look. :)
  10. Mike Dimin

    Mike Dimin

    Dec 11, 1999
    There are 2 numbers which need to be taken into account: the 3db roll-off, which is the topic of this conversation and the 10db roll-off point which is usually not published by manufacturers. The 10db roll off is of much more value to see how a cabinet will perform in a live setting
  11. jokerjkny


    Jan 19, 2002
    NY / NJ / PHL
    just to add as an aside,

    i was talkin' with Mike Dimin about cabs trying to hit the Low B, and he threw this out for me to chew on:

    When manufacturers rate their cabs, they do so at, what is called, the 3db roll off. To really see how a cab performs on a low B, the more telling stat would be the 10db roll off point.

    If a cab hits the 3 db point at 40 then very slowly continues to roll off and the 10db roll off is way below the low B- that is better than a cab that is rated at 35 db but has a sudden and immeidate drop to the 10 db roll off. EA represents the first example (although I am not quoting actual numbers)

    I hope this wasn't too ramblin' . It is also unfortunate that cab manufacturers (including EA) don't publish the 10db roll off. I do know, however, in EA's case that the 10db roll off is a definite consideration in the design of the cabs.

    Hope this is some explanation

    EDIT: oops, guess he beat me to the punch ;)
  12. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA

    Sorry, I wasn't too clear on the previous post. Phil Jones' measurement method, that he used to create his charts, is a "real world" method. That's why his charts show a "real world" response. If you're going to take a B+K mike and stick it a half inch from the coil, that's not a "real world" method. That says absolutely nothing about the speaker's ability to get 31 Hz "out there" into the audience. The result is marketing drivel, plain and simple, and any numbers you come up with in that context are largely meaningless in terms of a real world bass playing situation. Such numbers are valid for comparison purposes (only), and that's about it.

    In the pro-audio world, they distinguish monitor speakers in terms of their intended application. For instance, they use terms like "near field" and "mid field", depending on the listening application. Bass cabs in stage applications are probably in a "far field" mode, and therefore any measurement that purports to show what the speaker can really do, "in real life", should use a far field measurement method.
  13. Mike Dimin

    Mike Dimin

    Dec 11, 1999
    The only problem with that is you cannot compare these specs to other cabinets. Unless there is a uniform method of measurement, no comparison can be made.
  14. metron

    metron Supporting Member

    Sep 12, 2003
    -10 dB doesnt really mean anything useful because not much below -3 dB is coming through the speaker. The -3dB value is used as a standard and is called the half power point. At these frequencies twice the power is required to amplify to the level of frequencies at 0 dB. Speaker frequency response is measured between -3 dB points and usually rolls off quickly below and above these frequency points. All things being equal (methods of measurement) it gives the useful frequency range being amplified. Anything below or above is not really being amplified.
  15. metron

    metron Supporting Member

    Sep 12, 2003
    The -3 dB values are called half power points. This means that when you reach those frequencies that are specified as -3 dB points, it takes approximately twice the power dissipation to reach equivalent volume of frequencies in between. Its really not something to bother with very much. Many manufacturers strive for values below 41 Hz because thats the frequency of the fundamental of the E string.
  16. Mike Dimin

    Mike Dimin

    Dec 11, 1999
  17. metron

    metron Supporting Member

    Sep 12, 2003
    Yeah. For EA too! :D Sorry but decibels are real physics and not speaker brand specific. Once again for all things being equal (methods of measurement) EAs -3 dB point has the same meaning as any speaker manufacturers.

    Usually because roll off isnt the same for everyone but for the most part the roll off below is fast. Below -3 dB there isnt much fundamental being amplified.

    Frequency response of a speaker is independent of the room that you are playing in unless the speaker manufacturer in question uses the room somehow to measure frequency response. In that case the numbers are flawed and meaningless. -10 dB doesnt mean anything useful other then that frequencies at this point arent being heard.

    Physics is boring. :oops:
  18. chiplexic


    Apr 21, 2004
    O.K. I read here and on manufacturer specs the "tuning of the box" mentioned often enough. I have come to think of this as something aside ,if you will, from freq rating line graphs and spec sheets of the speaker and cab package. I think of the box tuning, in my laymen terms, as the one freq. were the box resonates as one with the speaker.That one magic frequency that they both meld together on.
    Like the way a room or a house vibrates like hell as you move around the bass neck but when you hit that one note everything vibrating just settles down and hums as one. That I assume is what is ment as box tuning. YES-NO ???
    If YES then why is it such a commonly mentioned spec since it's just one note ? One frequency. With all the other freq. on an instrument why make mention of just that one, be it 41hz, 50hz(such as Avatar cabs) ,45hz ...or any other ?
    I'm not questioning the importance of this spec but trying to learn why it's pointed out to the consumer when you only hit that freq once in a while as you play. Please enlighten me !
  19. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    There's another important issue that comes into play with bass cabinets, and that is the acoustic absorption of materials. A normal material like the plywood they use to build many of the popular cabs, reflects maybe 95% of the sound at high frequencies, so you're dealing entirely with air that's being pushed out to the audience from the cab. On the other hand, the acoustic absorption of plywood increases to almost fifty percent at low frequencies (beginning at, say, 50 or 60 Hz). Which means, that those low frequencies are going right out through the bottom of the cab, and into the floor, or whatever the cab happens to be sitting on. That's why people say that the ultra-low frequencies tend to travel through the ground, as opposed to arriving at your ear in the usual way like the highs do. So the "tuning" of a cab has a lot to do with the SPL that's developing "inside" the cab, and how that gets translated into the lows that get delivered "out there" into the crowd. And that's something that's exceedingly difficult to measure with a microphone. I'm not aware of any manufacturers that actually measure this, probably because it's so difficult and as Mike mentioned there's no standard for these types of measurements, but really it's probably the most important thing from a bass player's standpoint. I want my audience to "feel" the bass, and I depend on my cab(s) to be able to get the lows "out there" into the crowd, by whatever physical methods are available.
  20. Mike Dimin

    Mike Dimin

    Dec 11, 1999
    Speaker designers create speakers based on sound applications not specs. The specs come after. The specs are just a way to codify the design of the cabinet. Great designers, like John Dong of EA take many different things into consideration besides the specs. Each design element adds (or in some cases, subtracts) from the sound. One thing that John accounts for is that the room adds bass to the sound of the cab. By tuning the cab to have a slower roll off, much of the B fundemental is still present in the sound. Other things like driver alignment, transmission line, driver materials and design, crossovers, materials, baffling, acoustic coupling are all accounted for in a design that is, by all means, as much art as it is science.

    Specs are a great tool, but they do not tell the whole story. They are just a single way that manufacturers can compare and contrast.