Bill Fitzmaurice

[quote name='bass_ferret' post='136717' date='Feb 8 2008, 12:19 PM']If it is a black widow it it likely to be on the heavy side because they have higher power handling. There is more to light weight cabs than neo speakers i'm afraid.[/quote] There is no direct relationship between driver weight and power handling. Weight is mainly a matter of how large the magnet is. Drivers with large magnets tend to have high power handling mainly because large magnets are expensive, so they're found on expensive drivers, and expensive drivers tend to have higher power ratings because few customers would buy them if they didn't. The main factors that determine a driver's power handling are the voice coil and suspension.

It depends on the driver and magnet size. Many 15s weigh more than 20 pounds, and can be replaced with neos that weigh 10 pounds or less. But most tens weigh ten pounds or less, and a neo might shave only 2 pounds off that.

[quote name='Marcus' post='133218' date='Feb 3 2008, 02:32 PM']Bass Drivers and Guitar Drivers are constructed differently due to the nature of their respective jobs Guitar Cabs are usually built handle no more than 100W where as bass cabs can often handle many hundreds of watts Mark[/quote]It's not so much the power handling as the cone excursion that's different. The average guitar driver has 1mm of cone excursion, so it won't go very loud before compression and break up occur. The average bass driver has 4mm of xmax, which translates into 16 times the power handling before compression and breakup, all other factors being the same.

[quote name='barneythedog' post='133088' date='Feb 3 2008, 10:54 AM']My thinking has been pretty similar to yours I think - I like the idea of BFM's, but have been concerned over the Omni 10.5's low end response,[/quote] It's a 1x10. No 1x10 will knock down walls. But as far as that goes the O10.5 has no worse low end response than most 1x10s, and better midrange than any commercial 1x10 that I'm aware of. [quote]and much as I would love an Omni 15TB, it rather defeats the "compact and lightweight" idea I'm trying to achieve.[/quote]Hoffman's Iron Law: small, loud, low. Pick any two, you can't have all three. Sticking a 15 into too small a box will only result in loud, not low.

[quote name='bass_ferret' post='132462' date='Feb 2 2008, 05:57 AM']As is said in the thread Nik posted, wou are better having all 10's or all 12's. I would be tempted to pop up the road and have a listen to what Mark at BassDirect has to offer.[/quote] Absolutely. Mixing different drivers gives unpredictable results. I advise against a 4x10, it has no sonic advantages and more than a few disadvantages. Two 2x10 or 2x12 vertically aligned will give a much better result and make for an easier haul as well.

[quote name='presoulnation' post='131269' date='Jan 31 2008, 08:08 AM']Yeah I have just had a read through the sticky'd cab thread as well. I'm keen to get an idea as to how much the cabs are going to cost me to build really more than anything.[/quote] I can't say what they'll cost, other UK builders would have to chime in there. I will say that if your aim is to come out on the cheap DIY is not the way to do it, that would be used. For that matter there are many new options that cost less than DIY. Since you can't buy the materials at anywhere near the price that manufacturers can you can't compete with them where cost is concerned. Quality, though ,is a different matter. DIY has the advantage with the cost of labor, marketing and distribution. Manufactured cabs hold labor costs down by using designs that are simple, fast builds. The tradeoff in so doing is higher weight and lower performance than labor intensive DIY designs. And then there's the cost of all those ads. Another alternative is custom builders. They don't offer the savings in labor costs, but they also don't have the marketing and distribution overhead that manufacturers do, so you can get a superior product while not spending any more, and sometimes even a bit less compared to 'boutique' brands.

[quote name='onehappybunny' post='130753' date='Jan 30 2008, 11:02 AM']Messing around on ebay came across these amp stands which could be useful... [url="http://www.giraffemusicstands.co.uk/?page=product&group=Guitar%20accessories&id=41"]Giraffe amp stands[/url][/quote]These are better, as they allow you to lift the box above the stage as well as tilt it. Lifting the cab can help in boomy rooms by reducing midbass boundary reinforcement from the floor.

[quote name='gilmour' post='127799' date='Jan 25 2008, 10:19 AM']All of the internal bracing is in (I didn;t take pics it's not very exciting, and with the screen on my camera not working it's also very difficult), except for the bracing over the rear acces panel, I realised that if I put this in then I won;t be able to fit the driver through the gaps.[/quote] Right. The driver should fit through the opening on an angle, but it's a tight fit. I'll alter the plans specifying the opening size .

The bulk of the excess adhesive can be easily removed with a sharp chisel, using a planing action. Much faster than sanding.

[quote name='Jamesemt' post='124256' date='Jan 20 2008, 06:22 PM']They seem like a lot of money, but would go with my Superfly head.[/quote] Mine works fine with a single 1x10, but my single 1x10 has 106dB sensitivity. As far as conventional cabs go I'd be looking at a pair of 4 ohm 2x10s with neo drivers. Leave one at home when you don't need it. Can't say about the specific Ashdowns.

[quote name='tinyviking' post='123199' date='Jan 18 2008, 06:38 PM']I've been looking at BFM Omni's or perhaps another more standard 2x10 or 2x12 design as I've read on other forums a debate regarding wether or not the BFM bass horn style delivers any real advantages in smaller cabinets;[/quote] Let me guess: on one side those who have never seen, let alone heard, one of my cabs, but know all the answers, beating down the opinions of those who do own them. You don't have to be an engineer to figure out which of those groups has the more informed opinion. But as to the question, if one did horn load a woofer in a cabinet with the same net volume as the average commercial 1x10 it wouldn't work. Therefore, I don't.

[quote name='bigjohn' post='122908' date='Jan 18 2008, 10:17 AM']Hi Bill, Do you think a cabinet of 21" wide, 35" high, 15" deep is big enough to get 2x15s in? If I was to build one or have one made? I think your website answers me there... [url="http://www.billfitzmaurice.com/Omni10.html"]omni 10[/url] is 16"x20"x26 26" high, 20 wide, and 16" deep? Which should (just) fit in my boot? Is a 2x12? Is there any point me loading one of these with 2x200w 8ohm 12" and powering that with an svt3-pro? Would that be "louder" than what I've got?[/quote] Cabinet design is a far more complicated process than deciding on an arbitrary cabinet volume and then stuffing as many drivers as possible into it. Not that it isn't done that way, most commercial cabs are in fact, but it's not the right way. The best place to get specific answers vis-a-vis my cabs is on my forum.

[quote name='bigjohn' post='122806' date='Jan 18 2008, 07:55 AM']Running a 15" and a 2x10 would get full power from the amp -[/quote]'Getting full power from the amp' is by and large a wasted effort. If you double the amp's output you'll at best get an additional 3dB, which is audible, but just. Buggering up a combo will only make it valueless. If 150 watts into 1x15 isn't enough 300 watts into 2x15, or the equivalent thereof, is the minimum you need to make the change worthwhile. Either sell the combo and get a big rig or get the drummer the aforementioned smaller sticks, and perhaps a whack or two upside the head.

[quote name='dood' post='120298' date='Jan 14 2008, 01:23 PM']I suspect very few manuals include a schematic diagram of the amp. Though having said that.. it is *possible* to locate said schematics on the web instead.[/quote] A schematic isn't a necessity per se, the main idea is to see if the manual specifies dual voltage operation. Most amps from at least the last decade are, as it's cheaper for the manufacturer to stock one transformer that will work either way rather than two.

[quote name='Subthumper' post='119800' date='Jan 13 2008, 04:49 PM']Why not contact the shop in the states where you want to buy it before you go and see if they can get a UK export model? Could save a lot of agro. Cheers Just[/quote] Or download a manual.

[quote name='Jack' post='119059' date='Jan 12 2008, 06:31 AM']Yup, head->cab 1->cab 2 is still parallel if thats what you mean. I think the reason Eden have series on some of their cheaper combos is so a beginner can plug in ANY cab and not have to worry about impedance.[/quote] More likely the internal driver(s) is already at the amp's minimum load rating to maximize output. For example, all the Nemisis save the 15 are 4 ohm rated with 4 ohm speakers.

A transformer capable of handling the power draw of an amp will require no less than the same VA rating as the transformer in the amp, so you might as well just replace that. Before doing so RTFM and be sure the amp doesn't have a dual primary that can be reconfigured for 240.

[quote name='Jack' post='118542' date='Jan 11 2008, 09:17 AM']I think Bill was more about 'ohmage' than 'resistance'. Hey, at least youre aware of 'it', more than a lot of people.[/quote] The problem with the quasi-word 'ohmage' is that it could refer to impedance, could refer to resistance, could refer to inductive or capacitive reactance. Being non-specific makes it useless in an engineering context, so while it does appear in the vernacular it is not used by the engineering community. Resistance is only used with respect to speakers in its context as a component of impedance.

Gentlemen, the term is [b]impedance[/b]. Bad enough that we butcher the Queen's English as badly as we do on our side of the pond with words concocted out of whole cloth.

[quote name='Hamster' post='117886' date='Jan 10 2008, 09:58 AM']Well don't keep us all in suspense Bill! - which one is best? Hamster[/quote] Fuschia.

[quote name='gilmour' post='117671' date='Jan 10 2008, 05:15 AM']Does that mean an SWR Redhead would go Faster? [/quote] Laugh you may, but I recall many extended discussions between ostensibly intelligent human beings on a forum who debated ad nauseum over which color shrink wrap tubing on wire connections sounded better.

[quote name='Gray' post='117469' date='Jan 9 2008, 05:15 PM']Turbosound decided to use the 'turbo blue' paint colour on their cabinets because it sounded 'better' in blind listening tests...[/quote]Or they got a good price on a boatload of blue paint that no one else wanted.

[quote name='Gray' post='117184' date='Jan 9 2008, 12:22 PM']In PA world (particularly in regards to driving bins) its fairly standard practice to use amps which are twice the rated RMS output of the speakers they are driving (i.e. 1000 Watt RMS amp driving a 500 watt RMS cone). Gray[/quote]In the instrument amp world the opposite is very often the case. With PA systems one does not wish to have distortion anywhere in the signal chain. With instruments distortion, sourced both within the amps and the speakers, is part and parcel of the instrument tone. Bass in general doesn't go to the extremes that guitar does in terms of the distortion density, but when a bass player refers to 'growl' in his tone distortion is the source.

[quote name='warwickhunt' post='117116' date='Jan 9 2008, 11:28 AM']no amount of charts and graphs can account for it![/quote] Actually, they do. The problem is obtaining accurate data, or more to the point where the electric bass cab industry is concerned, any data.

[quote name='Crazykiwi' post='113533' date='Jan 4 2008, 08:57 AM']EBS rate their 212 at 103dB.[/quote]That would have to be a peak reading. There are no twelve inch drivers capable of that level broadband averaged. Twelves do exist that have 100dB sensitivity (making a pair 103dB), even a bit more, but they only achieve that sensitivity above 200 Hz or so. Below 100Hz, where it counts, 98dB is the practical limit in a direct radiator cabinet.