Which Is Louder, 2x10 or 1x15?

[greenboy]

I believe two 10" have slightly more surface area then a single 15".

I believe Santa brings huge presents through the little chimney and door in forced air furnaces.

Sorry. No prize for believing. Especially when you are wrong, and haven't even tried to explain why you believe that. Look at the figure called Sd on a driver datasheet to see the actual surface area of a cone. Not that it matters as much as the figure that describes how much air the driver can displace: Vd, which is Sd * Xmax.

 

[KJung]

You've said that more than once. It's like you believe these bass cab companies actually measure ; }

The figures are useless even if they actually came from measurements. Nobody knows for sure unless the spec includes more information about the figure, therfore they are UNREFERENCED. You don't know if that is a bandpass average, a highest point in the curve, a !K Hz number, or as is usually the case, a marketer's mood after good coffee.

Then there is the issue on how measurments are derived. If intelligent testing standards aren't sought out and adhered to that rule out a lot of variables like room effects, boundary loading etc, then the figures are useless anyway.

Bottom line. Forget 99% of the bass cab companies for honestly derived specs.

Actually, the 1K measurement that most of them publish lines up pretty well (i.e., there is a moderate correlation) with what I hear IME (i.e., that the ones that publish higher SPL have more upper mid response and typically less deep bass response).

However, your point is probably more useful... don't assume a higher or lower published SPL cab is 'better or worse' or anything for that matter.

 

[bassman251]

One 15" has the same area as two and a half 10"s. Area is proportional to the diameter squared! (And the working diameter is always less than the nominal diameter because the frame and surround are not part of the radiating area).

Alex

Yeah, actually I did get that backward...lol Did you take in account the angle of the speaker cone? That would increase the surface area as well. Or is it all that stuff in the parenthesis?

 

[greenboy]

Actually, the 1K measurement that most of them publish

I don't think you got it, Ken. Where does it say in all the bass cab specs, measurement derived at 1 KHz, 1w-2.83 volts/1m? I'm not seeing that in a variety of companies' marketing lit. Nor am I seeing, 'derived in halfspace' or anything about AES testing standard number xxx.

 

[KJung]

I don't think you got it, Ken. Where does it say in all the bass cab specs, measurement derived at 1 KHz, 1w-2.83 volts/1m? I'm not seeing that in a variety of companies' marketing lit. Nor am I seeing, 'derived in halfspace' or anything about AES testing standard number xxx.

While you are correct that the websites for many companies don't supply this information, most of the more detailed owners manuals do at least state that the SPL was derived 1K/1W. You are correct, not all, but many (SWR and Eden for example) list this slightly more informative SPL spec at the back of their manuals. I believe Bergantino lists this on his site also, along with many others that I'm familiar with (Acme, etc.).

Now if these companies are lying about it, I can't say. But again, I find a relatively high correlation between the published 1K/1W SPL spec and mid response of a cab (positive correlation) and the low end extension (negative correlation) that it seems reasonable that most companies are at least doing this measurement. For example, Eden is one company that gets a lot of grief for their very high published SPL. However, the XLT cabs are the ones that have the stupid high SPL spec, and guess what... they have a very high -3db published roll off, and are among the most 'upper mid voiced' cabs I've heard. That seems to correlation quite highly with the 1K/1W testing method. You may hate the tone, but they are loud as heck in the midrange and have much more upper bass than lower bass, making the cab very 'loud per watt'!

Again, I agree with you, the SPL measurements that these companies present are not very useful in the grand scheme of deciding which cab is for you and how much power is needed, etc.

 

[alexclaber]

Yeah, actually I did get that backward...lol Did you take in account the angle of the speaker cone? That would increase the surface area as well. Or is it all that stuff in the parenthesis?

Angle of the cone doesn't matter - it's the projected area that does. Similar to aerodynamics on cars - you have frontal area (which is a projected area) and then drag coefficient, and you need both to know how aerodynamic a car is. With speakers you have Sd (projected moving area) and Xmax (linear excursion), resulting in Vd (volume displacement, i.e. how much air a speaker can move!)

Note that this also depends on the ability of the port to handle an equal amount of air movement without going seriously turbulent - undersized ports may allow you to build a smaller cab and sound just as good in the shop but once you're cranked up loud they start doing very bad things indeed.

Alex

 

[greenboy]

Eden is indeed way off in WC Fields la-la land. Why base your hypothesis on a company that has specs that are not possible by any referenced means? There simply are no drivers that could do duty in a bass cab that could make such figures possible unless you are talking the compression driver and horn turned up full for the 410 and partways for the 210 ; }

 

[greenboy]

Eden is one company that gets a lot of grief for their very high published SPL.

They also should recieve grief for their frequency response numbers.

 

[KJung]

Eden is indeed way off in WC Fields la-la land. Why base your hypothesis on a company that has specs that are not possible by any referenced means? There simply are no drivers that could do duty in a bass cab that could make such figures possible unless you are talking the compression driver and horn turned up full for the 410 and partways for the 210 ; }

Again, I agree with you. The absolute SPL numbers are not that interesting. My only point was that a) at BEST, these SPL figures are derived using what seems to be the standard 1K/1W measurement (based on the majority of owners manual information that have come with the cabs I've purchased and b) given the many, many GTG comparisons we've done, there seems to be a meaningful correlation between the general voicing of the cab (and hence perceived loudness, primarily in the midrange) between the published SPL figures and the actual performance of the cabs. This would make sense if the majority of SPL measurements, even if overstated, where based on measuring that upper mid response of a cab.

So, again, you are saying the numbers are totally useless. In my experience, if you do put that 1K/1W assumption around the published figures, the SPL specs seem to provide limited information about the voicing of the cab. IMO and IME!

I'm with you. I would never suggest anyone buy a cab using published SPL and/or -3db roll-off as the primary or even secondary determinant of performance. However, IMO and IME, it is not completely useless information, given the real and more than trivial correlation I've found over many different cabinets.

IMO and IME!

 

[KJung]

They also should recieve grief for their frequency response numbers.

Not defending Eden at all. However, someone published the frequency plot of the 210XLT a while back, and there was a huge lift in that upper mid area, and a pretty sharp roll-off below 50hz, with the peak of that frequency curve being easily 6db above the start of the roll-off (i.e., +/- 3db). And while I don't particularly like that cab given all the peaks and valleys, it is LOUD in the midrange.

Of course, to your point, it might really be +/-10db.. I don't know. However, again, from a general voicing perspective, the specs do at least 'suggest' correctly the performance of that cab.

 

[greenboy]

Not defending Eden at all. However, someone published the frequency plot of the 210XLT a while back, and there was a huge lift in that upper mid area, and a pretty sharp roll-off below 50hz, with the peak of that frequency curve being easily 6db above the start of the roll-off (i.e., +/- 3db). And while I don't particularly like that cab given all the peaks and valleys, it is LOUD in the midrange.

Not denying that, Ken. I am, as always not talking about the actual products or their application - just that the specs are not jibing with the actuality. Eden is only one among many who this it true of.

Carvin would be another good example. During one period their bass cab specs and graphs were fairly indicative of their actual performance, but as new products were introduced some of those for the older units were "adjusted" and got a little iffy, and the newer products bore specs that were not possible in any sane testing methodology... Also, for the most part they did not pursue the same line of numbers marketing with their PA lines, though in fact the drivers were often one and the same. The PA products were more in line with what the drivers themselves were capable of.

Also, I am not trying to beat on you, Ken. If someone else would have brought this up I'd try to do the same: just talk about why the numbers are unrealistic. You cannot have both incredible spans across frequency response in a +/- 2 or 3 dB range AND these huge sensitivity ratings, and usually you can't have EITHER one alone...

When I came into bass playing and was looking to buy my first rig, being in the sticks, my first stops before going on pilgrimage to Bass Northwest and a bunch of other places, were websites. I was SHOCKED how far beyond, in numbers and vagueness these bass products were compared to the very detailed referenced specs I saw for good SR products that I had also heard and used. The SR products actually could do what they said, and peer review among pro users assured that companies couldn't easily get away with any major porkies that are so common over here in basscabland.

 

[tombowlus]

Lets have a graph of SPL then, where is that Tom Bowlus chap!, having another free lunch from yet another gear manufacturer no doubt.
Get him on the case, perhaps he might be able to introduce a gear manufacturer called Bruel and Kajaer to the professional bass player.
http://www.bksv.co.uk/Products/SoundLevelMeters/PCSoftwareforSoundLevelMeters.aspx

Give us some time. We're working on it!

No free lunches, though. I think I'm getting gypped!

 

[tombowlus]

Perhaps Tom thinks that this would radically limit his intake of port
and cigars and somewhat curtail his most poetic waxings.
"A picture paints a thousand words" as the old song goes.

Nah, you see, that's the beauty of the "dual review" format. I (or another BGM reviewer, like Vic or Chef) get to wax poetic about how nicely the cab blends in with the home decor, and how it's a great cat toy or whatnot, and then we have technical types like Tom Lees to do the dry, boring, technical review.

 

[tombowlus]

Then there is the issue on how measurments are derived. If intelligent testing standards aren't sought out and adhered to that rule out a lot of variables like room effects, boundary loading etc, then the figures are useless anyway.

You nailed it. In fact, finding the best environment for cab testing has been a major challenge. I think we finally have it licked, though.

 

[KJung]

Not denying that, Ken. I am, as always not talking about the actual products or their application - just that the specs are not jibing with the actuality. Eden is only one among many who this it true of.

Carvin would be another good example. During one period their bass cab specs and graphs were fairly indicative of their actual performance, but as new products were introduced some of those for the older units were "adjusted" and got a little iffy, and the newer products bore specs that were not possible in any sane testing methodology... Also, for the most part they did not pursue the same line of numbers marketing with their PA lines, though in fact the drivers were often one and the same. The PA products were more in line with what the drivers themselves were capable of.

Also, I am not trying to beat on you, Ken. If someone else would have brought this up I'd try to do the same: just talk about why the numbers are unrealistic. You cannot have both incredible spans across frequency response in a +/- 2 or 3 dB range AND these huge sensitivity ratings, and usually you can't have EITHER one alone...

When I came into bass playing and was looking to buy my first rig, being in the sticks, my first stops before going on pilgrimage to Bass Northwest and a bunch of other places, were websites. I was SHOCKED how far beyond, in numbers and vagueness these bass products were compared to the very detailed referenced specs I saw for good SR products that I had also heard and used. The SR products actually could do what they said, and peer review among pro users assured that companies couldn't easily get away with any major porkies that are so common over here in basscabland.

+1 all the way. I enjoy the topic and discussion.

 

[greenboy]

You nailed it. In fact, finding the best environment for cab testing has been a major challenge. I think we finally have it licked, though.

Tom, I have to applaud you and the crew over there. You've risen the big challenge that in bassland was always neglected. Each step of the way you folk have come up another notch. I've always discounted all the poetic subjective waxing or dissing unless it was founded on a bedrock of objective strength. That context does so much to keep the ear's and the mind's subjectivity in perspective. I like to think that the great lunch or the long working hours didn't just write a gear review singlehandledly, that emotional bents of the moment didn't make once piece of gear bask in the sun while another was untowardly relegated to the shadows.

Anyway, it is a Big Challenge. And you people are making real headway, and educating readers too!

 

[tombowlus]

Tom, I have to applaud you and the crew over there. You've risen the big challenge that in bassland was always neglected. Each step of the way you folk have come up another notch. I've always discounted all the poetic subjective waxing or dissing unless it was founded on a bedrock of objective strength. That context does so much to keep the ear's and the mind's subjectivity in perspective. I like to think that the great lunch or the long working hours didn't just write a gear review singlehandledly, that emotional bents of the moment didn't make once piece of gear bask in the sun while another was untowardly relegated to the shadows.

Anyway, it is a Big Challenge. And you people are making real headway, and educating readers too!

Thank you for the kind words! In all honesty, the technical testing has been a ton more work than any of us had envisioned. At times, it has been very frustrating, too. But that makes it all the more fun when you do find a way to crack the nut. Accurate measurement of bass enclosures (that is representative of how you actually perceive the output from multiple drivers, etc.) has been one of the biggest challenges, no doubt.

Tom.

 

[Kenny Allyn]

Nah, you see, that's the beauty of the "dual review" format. I (or another BGM reviewer, like Vic or Chef) get to wax poetic about how nicely the cab blends in with the home decor, and how it's a great cat toy or whatnot, and then we have technical types like Tom Lees to do the dry, boring, technical review.

No "fluff reviews" at BG ...


... These guys are all brass knuckles, I can attest to that!

 

[RickenBoogie]

Good spot for me to also thank you, (Tombowlus), for the information your magazine provides. Makes it easy for a 'tard like myself to get a better understanding of my own gear. Also enlightened me on the word, "gypped". I can see now the basis of where that word was derived, roving bands of dishonest gypsy-folk. Very cool with my morning coffee. Thanks.

 

[tombowlus]

Also enlightened me on the word, "gypped". I can see now the basis of where that word was derived, roving bands of dishonest gypsy-folk. Very cool with my morning coffee. Thanks.

The whole bass gear review thing is really just a means to an end. My true passion in life is the dissemination of nigh useless and/or trivial knowledge.

Thank you all for the kinds words!

Tom.