Bill Fitzmaurice

[quote]However, not a single one of them has a EBP of less than 155 and most are in the 200 / 300 range . any thoughts Bill ?[/quote]You can use a high EBP driver in a sealed cab, you just won\'t get any bass response from it. [quote]Im beginning to spot a correlation between higher power handling and higher EBP here[/quote] Pure coincidence. [quote]maybe vintage speakers tended to have a low EBP ?[/quote]Nope. Look at old JBLs and EVs. The main reason why sealed cabs dominated until the mid 70s was the lack of widespread knowledge of how drivers functioned, and that applied to the people that made them as well as everyone else. That knowledge was quantified by Theile and Small in the mid 1960s, and it took ten years before the electric bass cab industry began to take notice. A good argument can be made that many manufacturers still haven't caught on.

[quote name='Monz' post='635622' date='Oct 24 2009, 04:09 PM']As far as I am aware "Infinite Baffle" means the wood that the drivers are attached to is an integral part of the cabinet construction i.e. stressed member[/quote]Infinite baffle is where the front and rear waves of the driver are isolated from each other. That may be via use of a 1/2 cubic foot sealed box, it may be by mounting woofers in a wall between two rooms of a house. The roughly 4.5 cu ft cab of the OP will work well sealed with drivers that have an EBP of less than 75, vented with drivers with an EBP of more than 100, with in between 75 and 100 being OK either way. Delta Pro 12s would require the cab be vented and tuned to 45 Hz. To stay sealed the Beta 12 would work better.

[quote name='alexclaber' post='635251' date='Oct 24 2009, 07:59 AM']if the slope and frequency of the internal passive crossover is different to the active crossover on the GK then it'll make the cab sound different.[/quote]Maybe, but that might not be a bad thing. The intent of the G-K is to allow overdriving the lows while keeping the highs clean so as not to harm the tweeter. It's a good idea, but somewhat flawed in the execution, as the G-K highpass is fixed, so you can't adjust it to suit whatever tweeter it's used with.

[quote name='trent900' post='635016' date='Oct 23 2009, 07:33 PM']A mate of mine who knows a gnat or two about electronics (or so he says) suggests opening up the back of the Epi and modifying it so that it also can use the GK's horn amp with a 4-way cable. Jon[/quote]It could work very well if the tweeter is designed to operate at the same crossover frequency as the G-K. But if not it could be a problem so you'll have to be sure of that.

Could be the driver exceeding its excursion limit, maybe even the coil hitting the backplate, it could be the amp out of headroom also. The added excursion and power demand that results from boosting the low EQ could cause both symptoms.

[quote name='zephead' post='634031' date='Oct 22 2009, 06:57 PM']errrrrrrrrrrrr........................what are they?[/quote] They're of little use with cabs that aren't specifically designed to work with bi-amping, and of the current crop of commercial bass cabs there are none. You'd have a fair enough result with a 2x15 for the bottom and a 2x10 sealed guitar cab on the top, using around 300 Hz for the crossover frequency, but with two bass cabs running both full range will probably work better.

[quote name='waynepunkdude' post='632946' date='Oct 21 2009, 05:34 PM']It's this one. [url="http://www.samsontech.com/products/productpage.cfm?prodID=1691"]http://www.samsontech.com/products/product...cfm?prodID=1691[/url][/quote]There's not one useful bit of information there that might indicate how it will actually work, but that's not the exception, it's the rule.

[quote name='Mr. Foxen' post='632484' date='Oct 21 2009, 10:54 AM']People do have a habit of writing about it on the internet though.[/quote]That they do, but consider that the specs on probably the most envied driver, the original CTS Ampeg SVT, are not to be found anywhere. For that matter those on the current Eminence SVT driver are also unavailable. I've got them, but like all those in the industry I won't reveal them, as it's privileged information. As for measuring them yourself, unless you've got a Klippel analyzer handy, or tear the voice coil out to measure the coil length and plate thickness, that all important xmax remains an unknown. It's easier to just schlep your rig into a store and try cabs.

[quote name='Mr. Foxen' post='632407' date='Oct 21 2009, 09:37 AM']Find out what speakers are in it[/quote] Good luck. Most manufacturers are less forthcoming about the drivers they use than Joan Collins is with her birth date.

[quote name='waynepunkdude' post='632109' date='Oct 21 2009, 04:28 AM']I'm looking at a 2X15 that is 500W @ 4OHMS my 4X10 is 600W @ 8OHMS would the uneven load cause a problem or will it be fine as it is off of 2 separate power amps?[/quote]It won't bother anything, but beware of power ratings that are meaningless, which most are. What counts isn't the thermal rating, it's the displacement limited rating, and no one provides that. Try before you buy.

[quote name='Musky' post='629721' date='Oct 18 2009, 02:21 PM']Running the MAG 600 into a 4 ohm load, the amp will be capable of knocking out it's full 575 watts if you turn it up full. Which obviously you don't want to into a cab that can only handle 400 watts.[/quote]Of more significance is that most 400 watt cabs will take no more than 200 watts before farting out, so running a 4 ohm cab to 'get all my watts' is a wasted effort in the short run and the long run as well.

[quote name='GreeneKing' post='613372' date='Sep 30 2009, 05:31 PM']If the amp has a max output of 200 watts or thereabout into 4 ohm, and you add an extension cab in [b]series[/b] to increase the impedance seen by the amp then the output will fall.[/quote]If the extension cab is identical the sensitivity will remain the same, as the 3dB lost to the doubled impedance will be offset by the 3dB gained via mutual coupling. In all maximum SPL will probably go up, as the fifteens typically used in combos are displacement limited to only 50 watts or so. Running a combo at minimum impedance with the internal speaker is rare, but not unique; Eden Nemesis does so and also runs the extension speaker in series.

[quote name='krispn' post='629538' date='Oct 18 2009, 10:33 AM']Seen one of these on evilbay and was wondering would a 100 tube power amp be enough for a bass rig? and would it be clean enough? Thoughts?[/quote]It depends on the speakers. More drivers means higher sensitivity, so you need less power. 100 watts from a tube amp into an 8x10 would certainly handle most any venue. But not through a 1x or 2x, maybe through some 4x.

[quote name='Count Bassy' post='627478' date='Oct 15 2009, 06:44 PM']I've read through this thread and am still a bit confused. Am I right in thinking then that ported cabs should be lined and that sealed cabs should be 'stuffed'.[/quote] Not necessarily, sealed cabs only need to be stuffed when they're too small for the drivers within. But that situation probably applies to 99% of the sealed cabs made. For instance, the SVT ten inch drivers are happiest in 6 cubic feet...each. [quote]I've suddenly become interseted as I've just opened up my Marshall combo (to fix an amp problem) and notice that the (sealed) cab part has no lining or stuffing of any sort.[/quote]I'd call that unbelievable if I didn't know better. Line or stuff it, based on ported or sealed.

[quote name='derrenleepoole' post='624379' date='Oct 12 2009, 03:34 PM']Well, my SF ran VERY hot -[/quote] So did mine, due to a design flaw. The heavy aluminum external chassis is not ribbed, to act as a heat sink, but is solid, retaining heat. It also doubles the weight of the amp. I removed that, mounted the amp in a rack, added a fan and it runs cool to the touch. You'll note that the LG has abandoned the aluminum crap and added a fan.

[quote name='derrenleepoole' post='624238' date='Oct 12 2009, 01:34 PM']I presume this has been covered then? Did a search but nothing came up - or I missed a thread? If there is a link to a topic on this, could you post it? Cheers...[/quote] You can use them with any head. Their only claim to fame was the stereo wiring that allowed each half of the driver complement to be hooked up to each of the two power amps of the SF head. BTW, I have a SF and I find it not the least bit underpowered, and that's into one 8 ohm cab, albeit one of much higher sensitivity than off the shelf. I can't see a LG not being able to push a SF cab to full output.

[quote name='alexclaber' post='623937' date='Oct 12 2009, 08:28 AM']Interesting. If the increase in compliance was due to a lowering of the speed of sound one would expect this to be consistent with larger boxes - so does this suggest that a larger box is inherently more isothermal due to the greater heat capacity of the air within it and the greater radiating area of the enclosure? I presume overstuffing is counterproductive because the increase in compliance due to heat absorbtion is offset by the decrease in actual net volume. Alex[/quote]The changes offered by stuffing have nothing to do with either lowering the speed of sound or heat. They're the result of the alteration of system impedance by the higher mass load of a stuffed rear chamber versus unstuffed. And that's why the response of a larger box is impossible, because stuffing is a passive component, and passive components can never add energy, they can only consume or reallocate it. Depending on system Q stuffing can reduce a midbass peak with little alteration otherwise to broadband response, and it can lower system Fsc while lowering broadband sensitivity. But what it cannot do is lower system Fsc while maintaining or even increasing broadband sensitivity, wheras a larger box can do just that. As to the heat increase exhibited in a stuffed box, there are two sources. One is the higher coefficient of friction offered by stuffing versus air to the rear wave, and where there's friction there's heat. The other is the insulation value of the stuffing, which retains not only the heat created by the stuffing but that of the driver motor. Measuring a higher temperature within a stuffed versus unstuffed box isn't the least bit unexpected, it would be inexplicable not to.

That's a lot of knobs for an older bass rig, be sure it's not guitar.

[quote name='tom1946' post='623105' date='Oct 11 2009, 09:14 AM']Are there any quietly powerful amps out there with maybe an ability to just flick a switch to silently kill it while things like prayers and readings are going on?[/quote]Those with a built in noise gate or downward expander. Pedals exist to do the same thing with your bass, most rack mount compressors also include a noise gate and/or downward expander.

[quote name='fenderiko' post='623194' date='Oct 11 2009, 10:59 AM']I disagree . I have the feeling that you need to speak, play , hear and interact with more guitar players. R[/quote]I play both guitar and bass, so I can speak on both sides of that great divide. For whatever reason I see a much higher percentage of guitar players falling into the "If Jimi/Eric/Stevie Ray (fill in your favorite Guitar God name) used it then that's what I need" mindset than bass players. OTOH I also agree that the technology of electric guitar peaked circa 1959, and that you can't get a better tone than a '59 Tobacco Burst or Strat through a '59 Bassman. Where the epitome of electric bass technology is concerned we haven't reached it yet.

[quote name='fenderiko' post='623156' date='Oct 11 2009, 10:11 AM']for me tone come first. then figure out if I can afford the damn thing . R[/quote]For me tone come first too. The point made is that weight and tone are not related. Some very heavy cabs sound really bad, some very light cabs sound very good. Having a cab that sounds good and is light as well is a win-win situation.

[url="http://billfitzmaurice.net/phpBB3/viewtopic.php?f=14&t=4140"]http://billfitzmaurice.net/phpBB3/viewtopi...f=14&t=4140[/url]

[quote name='Musicman20' post='622008' date='Oct 9 2009, 03:44 PM']I know it applies more to their guitar cabinets, but the Orange cabinets are made from 13 ply high density 18mm birch plywood. Is this an example of fast labour?[/quote] Probably. 18mm Birch does make a nice cab, and requires minimal bracing, so it's a fast and easy build, giving a good result with minimum labor costs. With adequate bracing 12mm birch can give just as good a result, with a lot less weight, albeit with higher build costs. If you price out 12mm versus 18mm you'll find not that much difference, not nearly enough for the materials savings realized using 12mm to come close to compensating for the additional labor that material demands for an equal result. Ask any structural engineer the best way to build anything to realize maximum structural integrity, stiffness and strength to weight ratio and they'll always reply [i]with minimal material thickness and maximum surface to surface bracing[/i]. An aircraft or boat serve as good examples of lightweight high strength construction. A Centurion tank is certainly strong enough, but it will neither float nor fly.

[quote name='stevie' post='621899' date='Oct 9 2009, 01:30 PM']His explanation about how stuffing works may be incorrect (although I think if you slag off Richard Small the least you could do is provide some supporting references) but the practical consequences of stuffing a sealed box are the same – you increase the effective box size! Call it increasing the compliance of the enclosure or lowering the system Q - these are both things that happen when you increase the size of the box.[/quote]When stuffing is used to achieve a lower Q overall system sensitivity and extension will be minimally altered, if at all. When a larger box is used system sensitivity will go up and extension will go lower. Using stuffing to lower Q can mimic the flatter response of a larger box, but it won't give the greater sensitivity and lower extension of a larger box.

[quote name='Balcro' post='621785' date='Oct 9 2009, 11:44 AM']Could the manufacturers also do this to deliberately give the speakers a rougher sounding edge? Balcro.[/quote]One could make that case, but the more likely explanation is that they don't want to add to the build cost of the cab by properly lining it. They'd feel quite safe in so doing based on the facts that most users aren't aware that the cab should be lined, and those who do aren't likely to examine the inside of the cab before buying one.