Bill Fitzmaurice

Without reverse engineering the cab and then using a speaker modeling program to determine compatible drivers it's impossible to render anything other than a purely subjective opinion. In other words, a guess, which you'll no doubt receive in droves, most of which will have no more validity than if you were to put a list of drivers on the wall and toss a dart at it...whilst blindfolded.

[quote name='pete.young' timestamp='1477044139' post='3159410'] If your point is that one can't be an engineer unless one has a B.Sc. I disagree. Cambridge has a fine engineering department and doesn't award any science degrees. [/quote]+1. Perhaps it's different in the UK, but in the US no degree is required to be an engineer. Where FOH engineers are concerned BS degrees are as common as a BA in bass playing.

[b] [size=4]Full Definition of [i]engineer[/i][/size][/b] [list=1] [*][i]1[/i] : a member of a military group devoted to [url="http://www.merriam-webster.com/dictionary/engineering"]engineering[/url] work [*][i]2[/i] [i]obsolete[/i] : a crafty schemer : [url="http://www.merriam-webster.com/dictionary/plotter"]plotter[/url] [*][i]3[/i] [i]a[/i] : a designer or builder of [url="http://www.merriam-webster.com/dictionary/engines"]engines[/url][i]b[/i] : a person who is trained in or follows as a profession a branch of engineering[i]c[/i] : a person who carries through an enterprise by skillful or artful contrivance [*][i]4[/i] : a person who runs or supervises an [url="http://www.merriam-webster.com/dictionary/engine"]engine[/url] or an apparatus [/list] In this case the apparatus is the sound gear, so the term is correctly applied. In the US the guy running the board is commonly referred to as the FOH (front of house) engineer. I've worked with FOH engineers who were brilliant, and those who were total clods, and this was with first tier national and international touring acts. One of the worst I ever encountered worked for Ringo and his all-stars; he somehow managed to make Greg Lake sound really bad. Not surprisingly to me most of the best with respect to having the bass sound like the bass were themselves bass players.

[quote name='Beer of the Bass' timestamp='1476649585' post='3156030'] The Eminence Beta 12 does have that presence peak which sounds good for bass, but having played guitar through them I feel like they're still missing something that I can hear with Celestions or similar guitar speakers. [/quote]It's not what they're missing, it's what they have: excursion. A Beta 12 has 4.4mm xmax, a typical guitar speaker has 1mm or less. That allows a guitar speaker to go into compression and break-up mode at low power levels, the exact opposite of what you want a bass driver to do.

[quote name='Kyron' timestamp='1476570362' post='3155377'] Is there a modern speaker/cab that can provide the clarity and sharp response from the Vintage 30 fitted to my ENGL combo, but is designed to withstand bass frequencies? [/quote]Yes, one that uses bass drivers plus midrange drivers or one that uses bass drivers low-passed and guitar drivers in a separate compartment, high-passed. As for the latter that would probably require a custom build, I'm not aware of anyone who currently makes one. Another option is to put a guitar combo atop a regular bass rig. Since you'd have two amps that opens up all sorts of possibilities, including getting Chris Squire's signature tone the same way that he did.

[quote name='Beer of the Bass' timestamp='1475695365' post='3148093'] Other than being optimistically priced, is the concept a sound one for guitar use? And do the shaped bits and cutouts do much that a simple angled perspex screen wouldn't? [/quote]It would work, but it's far more complicated than necessary. A simple vertical slat in front of the cone would work, as would a donut. But a foam donut wouldn't work all that well, as too much sound would pass right through it. I'd use plywood. Both work on the principle of diffraction, explained here in section 1-5. http://www.jblpro.com/pub/manuals/pssdm_1.pdf

Just use a well designed cab that doesn't beam and you won't need one. That's pretty much impossible with guitar, as any twelve is going to beam the highs, but not so difficult with bass.

[quote name='Mr Bassman' timestamp='1475449443' post='3146060'] Two Faital Pro's would probably out perform 4 Fanes [/quote]That's not the case, as two 8PR200 have 325cc Vd, four Fane have 470cc Vd.

[quote name='Bigwan' timestamp='1475237660' post='3144278'] My question is, rather than going to the time (which I have little of) and effort of retuning the cab for optimum ported performance, could I take out the crossover and tweeter, patch the cutouts for the port and the tweeter, add some stuffing to the cab and use it as a sealed cab? [/quote]If you seal it you'll lose about 4dB of sensitivity below 100Hz, and 12dB of maximum SPL at 50Hz, which is huge. If you don't use the tweeter you should pull the crossover. If it's not currently lined with damping material it should be.

[quote name='fleabag' timestamp='1474752146' post='3140319'] There's no cab extension out on the combo amp [/quote]Add a jack to the back of the speaker cab wired parallel with the drivers.

[quote name='fleabag' timestamp='1474748833' post='3140275'] If Bill says there's no perceivable volume difference between using four x 4 ohm drivers and four x 8 ohm drivers, i may as well just get the 8 ohm type ? [/quote]I would. You never know if at some point you might want to use it with a second cab.

[quote name='fleabag' timestamp='1474597460' post='3139131'] In which case Bill, i'm assuming i'll lose a little output power changing to 8 ohm drivers ? [/quote]Not enough to make any difference.

[quote name='fleabag' timestamp='1474588517' post='3139119'] ...its power is into 4 ohms, thats it. [/quote]600 watts indicates a SS amp, and if the amp says 4 ohms that's the minimum impedance load. It will have no problem with an 8 ohm load.

[quote name='markstuk' timestamp='1474382308' post='3137531'] as far as I understand ported cabs are more efficient [/quote]They can have higher sensitivity in the lows, but that's not always the case. [quote]and can be smaller[/quote]Or larger.[quote] sealed cabs have a flatter frequency response[/quote]Some do, some don't. [quote]and therefore can be more accurate..[/quote]Or not. You can no more make a blanket statement about ported versus sealed than you can as to which is faster, a 4 cylinder versus 8 cylinder engine vehicle. My 4 cylinder twin-turbo BMW is a lot faster than my next door neighbor's 8 cylinder two-ton Toyota pickup truck.

The Sunn 610L guitar cab used that baffle configuration. I've never seen a bass cab that did. It wouldn't work well for bass because that shape makes the rear chamber too small.

[quote name='Beer of the Bass' timestamp='1473329249' post='3129094']if I was to do a bit of reading, pick out a tweeter that extended down to around 2KHz (like some of the P-Audio offerings), calculate the inductor and capacitor values using an online calculator and wire it up with some form of switchable or variable attenuation, how badly could I go wrong? [/quote]The problem is that those calculators assume a resistive load at the exact value of the driver nominal impedance. That's not what crossovers actually have to deal with. It will work, but not necessarily well. As for running the woofer full range, if you do there can be destructive interference between the woofer and tweeter outputs. One award winning commercial cab I designed went through a full year of Beta testing with many component combinations before the manufacturer settled on the final crossover design. It can make that much difference.

[quote] I will be building the 1x12 very soon and intend to put a piezo in it. [/quote]One is insufficient. Part of the reason why commercial cabs with piezos sound bad is that they don't use high pass filters, the other is that they don't use enough of them. At the minimum you want two piezos per woofer, vertically aligned, wired in series for one pair, banks of series/parallel for more than one pair.

[quote name='Kevin Dean' timestamp='1472980546' post='3125674'] How hard can it be ? [/quote]A lot harder than you think. First off, I'd use either a midrange driver or a tweeter that can run to 2kHz. The usual tweeters used in bass cabs go no lower than 3.5kHz, if that, making them more useful for creating hiss than anything else. Then there's the matter of the crossover. Designing a crossover is a skill only perfected with years of experience. Yes, there are off the shelf crossovers, but they aren't very good. There are on-line crossover component calculators, but they're far too elementary to give a good result.

[quote name='tauzero' timestamp='1472736162' post='3123771'] I think they missed a trick not making it bridging. [/quote]It was bridged. Each 250w amp consisted of two bridged 62.5w amps. You can't bridge twice, and even if you could the minimum impedance load would have been raised to 8 ohms anyway.

They're not optional, they're critical. I should imagine your tone is very boomy without them.

That would work.

[quote name='bassman7755' timestamp='1472300606' post='3120158'] IME even budget floor standers sound much better than quite an expensive subwoofer + shelf/satellite speakers setup. [/quote]That's the opposite of my experience.

I use one channel of a Fly into an 8 ohm 1x12, but it's a high sensitivity Jack 12 cab, not your garden variety box. Depending on what your Hartke are a pair of them, one per channel, may be OK.

[quote name='Biglump' timestamp='1472301376' post='3120163'] I'm thinking of making my own because there doesn't seem to be any 4 ohm 100 watt extension cabs around. [/quote]Why 4 ohm? And why 100 watt?

[quote name='bagsieblue' timestamp='1472203893' post='3119363'] I'd like to think it's a debadged readily available option.... [/quote]It may be, but we can't look inside your cab. Confucius say "picture worth thousand words".