Bill Fitzmaurice

You're not considering the most important charts, maximum power and maximum SPL.

[quote name='flyfisher' timestamp='1358029850' post='1932209'] My school physics lessons included wave theory demonstrated using called ripple tanks like this: [/quote]There are a few nice tools found along with this one, from your side of the pond,www.acoustics.salford.ac.uk : [media]http://www.acoustics.salford.ac.uk/feschools/waves/flash/diffractionslider.swf[/media]

[quote name='TimR' timestamp='1358011860' post='1931859'] At secondary school we do the double slit experiment with light. Anyone who has seen that will instantly understand about 4x10s. [/quote]I guess most bassplayers nod off during that demonstration.

[quote name='Mr. Foxen' timestamp='1358008915' post='1931799'] The bit your brain makes up is a bit harder [/quote]A bit, but people have been studying this stuff since circa 1876, so at this point there isn't anything in the realm of audio that hasn't been scientifically explained. But it's not the sort of stuff they teach in secondary schools, nor even at the university undergraduate level at most institutions, not even those with EE programs.

[quote name='chris_b' timestamp='1357915228' post='1930537'] How much of the science doe we hear in the sound? [/quote]Everything you hear can be explained by the science. If you don't think that's the case it's your understanding of the science that's incomplete. The good news is that you can learn the science, should you be so inclined. Or you can ignore it, even deny it. No matter, the science is always right, whether you believe in it or not.

[quote name='chilievans' timestamp='1357850263' post='1929598'] Evening all I'm thinking of making a bass cab but as its my first one I have a few questions that need answering first [/quote]More than a few, I'd venture. First off, you need to understand what this is all about: [url="http://www.eminence.com/support/understanding-loudspeaker-data/"]http://www.eminence....udspeaker-data/[/url] And then how to use that data in this: [url="http://www.linearteam.dk/default.aspx?pageid=winisd"]http://www.lineartea...x?pageid=winisd[/url] And then how to use the results from that to construct a box, with help from sources like this: [url="http://techtalk.parts-express.com/showthread.php?219617-The-Speaker-Building-Bible"]http://techtalk.part...-Building-Bible[/url] If it seems like that's a lot to have to go through just to build a speaker, it is. But building a speaker is a lot more involved than just sticking a driver into a box.

[quote name='aende' timestamp='1357656959' post='1926103'] Ah - I see where you are now. Okay the amp has 2 x 250w outputs (it has dual power amps) @ 4 ohm each. [/quote]In that case run a 4 ohm cab off each channel IF you never anticipate needing more than two cabs. If you do make the cabs 8 ohms, allowing you to use four cabs should you ever have the need.

[quote name='aende' timestamp='1357650829' post='1925944'] Special cables? The amp is designed around 4 ohm cabs! [/quote]Are you aware that when you run two 4 ohm cabs the load is 2 ohms ? The amp impedance rating applies to when you're using the maximum number of cabs that you ever intend to. If you intend to run two cabs they should be 8 ohm, so that the combined load is 4 ohms. It's true that you could series wire two four ohm cabs for an 8 ohm load, but that means the output of the amp will be less with two cabs than with one, which is the exact opposite of what you want.

[quote name='Ghost_Bass' timestamp='1357655710' post='1926071'] [/quote] Really. Isn't there a search function here?

[quote name='aende' timestamp='1357646231' post='1925800'] So, it will be 2 x 210 4 ohm cabs. Just need to grab the shells and buy a set of 8ohm speakers/parallel wire.[/quote]Bad idea. You want 8 ohm cabs. That way there's no need for special cables, which always succumb to Murphy's Law just before a gig. [quote] I'd email Blue Aran & ask what they'd suggest for a replacement for the Peavey driver.[/quote]I wouldn't give them credit for having that level of expertise. Either use the Peaveys or have someone with the requisite skill pick a suitable replacement for you. That means not only modeling different choices with speaker modeling software but also comparing SPL charts, as T/S modeling only works up to about 300Hz.

I once mixed for a band where the guitar player ran a 4x12. I asked if he wanted to be mic'd, he said no. When they played he was loud enough directly in front of the cab, but couldn't be heard at all anywhere else. First break he asked if he was loud enough, I told him he couldn't be heard other than directly in front of the cab and I should mic it. He said no, he'd just crank it louder. He did, it only got worse. But I didn't argue about it, because I'd learned long before that gig that you can't fix stupid.

[quote name='peteb' timestamp='1357325417' post='1921176'] However, it should be noted that all good rock drummers, without exception, are pretty loud! [/quote]No problem there, they use shields. The more considerate, not to mention knowledgable, guitar players do as well. I saw a guitar player a few months ago who was the best bluesman I've seen since Mike Bloomfield, and he was not only a magnificent player, he knew how to use his gear. His Fender Twin was towards the back of the stage, aimed at a 45 degree angle towards the wings. The audience heard it through the PA, those on stage heard it though the monitors, and it was perfect. His name is Rocky Athas, he tours with John Mayall, and he is every bit as good as any other player to ever work with John, including Clapton. So good that he doesn't need to stroke his ego with the size of his rig.

[quote name='0175westwood29' timestamp='1357307945' post='1920707'] surely this attitude is very similar to guitarist thinking that we should play a 115? [/quote]No, it's because they can't get a proper mix throughout the venue when the guitars are so loud directly in front of their cabs that they drown out a 30,000 watt PA, while ten degrees to either side of that they can't be heard at all.

[quote name='VTypeV4' timestamp='1357259784' post='1920164'] Don't get me wrong on a big stage where there is plenty of space they're great [/quote]Not even then. To a man the biggest complaint of the hundreds of FOH engineers I've worked with is guitar stacks. They all would rather the guitar'd players were using 1x12 or 2x12s. And this is the venue: http://www.meadowbrook.net/

[quote name='Mr. Foxen' timestamp='1357073902' post='1917261'] The 3012LF is 12" driver. No 12" driver is the best thing for the job over about 2k because they become directional above there. Thus to do the best job, you use the 12s up to the point they are the best and use something else higher. [/quote]Now you know how it feels to be a dog chasing his own tail.

[quote name='xgsjx' timestamp='1357048161' post='1916694'] I don't get it. Why would a sealed 8x10 handle bass bleed better than any other non sealed cab of any other configuration? [/quote]It won't. The Fridge is the 'industry standard' for the same reason the SM 58 mic is: you can always count on them to work. They're ubiquitous on TV and in venues where the kit is either owned by the house or rented. Neither is perfect in every application, but both will function in any application.

[quote name='Mr. Foxen' timestamp='1356959941' post='1915588'] The lows reach you fine, that is why micing cabs and headphones work. [/quote]+1, but what he's probably referring to, and the source of the myth of 'wave development', are boundary sourced cancellations that occur close to the source, masking the low frequencies. As one moves further back in the room one moves out of the boundary sourced null zones and the lows are better heard than when up close. This is basic acoustical engineering knowledge that every bass player should have as part of their mental kit.

[quote name='Wooks79' timestamp='1356888856' post='1914771'] Ah, Bill Fitzmaurice, the king of not answering a question [/quote]The OP wants to know if BFB is worth paying more for. What better way to demonstrate that than showing him exactly what the extra coinage will get him? Even if he doesn't know what the specs mean the difference between 115 and 175 quid should make the point clear.

[quote name='teaser360' timestamp='1356881786' post='1914646'] Are they worth the money [/quote]This, or a variation of it, is the most commonly used neo twelve: http://www.bluearan.co.uk/index.php?id=EMIDLIT2512&browsemode=manufacturer This, or a variation of it, is what you'll find in BFB twelve loaded cabs: http://www.bluearan.co.uk/index.php?id=EMIKLIT3012LF&browsemode=manufacturer

[quote name='pikeman' timestamp='1356513849' post='1910584'] I was recently in this situation. Normally the Compact was fine by itself but other times I had trouble hearing myself clearly when stood very close to it.[/quote]That's because you don't have ears in your ankles. The cure? Tilt the cab back. As for the OPs question, if one cab isn't enough, use two of the same model. The results with any other combination, even with another BFB model, are unpredictable at best.

Surge protectors are fine. Expensive power conditioners are not, as they can restrict current flow.

[quote name='4 Strings' timestamp='1355912277' post='1904223'] I have no evidence apart from my own anecdotal, I can respect that from the experience of likes of Alex and Maurice, and also the apparently opposing view presented from published articles by leading lights in the field. [/quote]Your own anecdotal can be just as vaild as some 'leading lights'. Take Vance, for example. For many years and editions of his book he espoused the notion that stuffing a sealed cabinet with damping duplicated the effect of a larger cabinet. He was wrong. He fell into the trap of accepting someone else's data and opinion at face value without confirmation, in this case that of Tom Nousaine, and Tom's conclusion was erroneous due to his having used incomplete data to arrive at it. I didn't accept Tom's conclusions without confirming them, and I found them incorrect. So have a number of other sources, and in his latest edition of his book Vance has revised his advise on the subject. The lesson that should be learned is that no source is infallable, and if you think something they say may not be spot on don't hesitate to confirm or disprove it for yourself. One's own anecdotal experience can be the first step in that process.

[quote name='Salt on your Bass?' timestamp='1355824532' post='1903091'] I used to own this head but didnt use that facility. [/quote]+1. I've never wanted for the lack of a pedal, it's not all that difficult to scroll through presets between songs.

[quote name='JohnFitzgerald' timestamp='1355317933' post='1896808'] Bill Might this explain the logic behind the slot opening in the old Trace BKLX combos ? [/quote]Slot loading makes the cab a bandpass, so that kills highs and mids anyway. But to the extent that they still are there a vertical slot will give wider dispersion than a horizontal slot. Diffraction is the mechanics in this particular instance, how it works is shown here: http://www.acoustics.salford.ac.uk/feschools/waves/flash/diffractionslider.swf While the diffraction model doesn't precisely explain the benefits of vertical placement, or for that matter the wider dispersion of a smaller driver, it's close enough.

[quote name='alexclaber' timestamp='1355317189' post='1896794'] The attached plots are the same driver, the first measured in the summer, the second measured in the winter - ignore the LF stuff because it wasn't set up for that, it's a midrange/treble response measurement. The lower temperature changes the cone and the suspension stiffness - and look what that does to the frequency response curve! [/quote]If I'm doing measurements in the spring or fall I take the driver/cab inside the house the night before, rather than leave them in my unheated shop. There's a significant difference between a measurement of gear that's at room temperature versus even 60F, let alone colder than that. I learned that the hard way measuring a new HL10c driver that I'd left out in the shop, where the ambient dropped to 35F overnight. Spec'd at 44Hz, it measured cold at 70Hz. [quote]If it was that critical, I would imagine that the driver manufacturer themselves, or at least the cab manufacturer would do the running in for you...[/quote]Break in takes time, time is money.