Bill Fitzmaurice

[quote name='Lfalex v1.1' post='143551' date='Feb 20 2008, 04:43 AM']Not exactly! They had two slotted ports in a baffle in front of the (single) 12"(?) Driver. More like a very short back-to-front transmission line enclosure...[/quote] A transmission line is a quarter-wave device, so anything less than three feet or so is more likely a reflex duct.

[quote name='tauzero' post='143106' date='Feb 19 2008, 10:15 AM']Are there any implications of the horn-loaded design that would preclude using moulded cabs?[/quote]Only the $250k cost of the molds. You have to sell a lot of cabs to amortize that, which is why you see cheap PA cabs that are sold by the boatload built that way, but not high end cabs that have yearly production runs at best in the thousands, if not hundreds.

[quote name='bass_ferret' post='143009' date='Feb 19 2008, 07:43 AM']Most efficient is going to be horn loaded cabs like Bill Fitzmaurice. Shame no bass cab manufacturer does anything similar and I cant help but wonder why.[/quote] The labor cost for a horn loaded cab is three to ten times that of a direct radiator. BTW, horn loaded cabs aren't necessarily any larger than direct radiators with equal capabilities, and in many cases are actually smaller. A horn loaded 1x10 can equal or better the performance of a direct radiating 4x10 of similar size. But the horn loaded ten might entail $500 labor cost to build, while that of the direct radiator is only $50. With the cost to the manufacturer of ten inch OEM drivers about $40 each the far more profitable route is the direct radiator.

[quote name='Mums fella' post='139319' date='Feb 13 2008, 05:04 AM']I didn't realise you had a preamp on your bass as well. Does the hissing go away when you disconnect your bass? Larry[/quote]Some hiss is inevitable, but this is where having a LPad on the tweeter to reduce its sensitivity can help to fine tune the system for the best result. That's usually obtained by boosting the highs as early as possible in the signal chain, starting at the bass if it has on-board, and cutting them at the opposite end.

[quote name='bass_ferret' post='139040' date='Feb 12 2008, 02:43 PM']It looks like Cerwin Vega dont sell their drivers and just do cabs now - serious cabs mind [url="http://www.cerwinvega.com/vegabass.php"]http://www.cerwinvega.com/vegabass.php[/url][/quote] Obsolete IMO, too large a driver coupled with too small a horn. The minimum length for a horn to work to 40 Hz is seven feet, and when you load an 18 into a box that size there simply isn't room for a seven foot horn. For that matter I wouldn't use less than a twelve foot horn in a box that size.

[quote name='thinman' post='139050' date='Feb 12 2008, 02:55 PM']I notice that the Basslite S2010 recommended by Bill is now stocked by www.bluearran.co.uk so I could consider them but I notice also that their power handling is 150W RMS compared with 250W for the others being discussed.[/quote]Not moot, but almost. Since the S2010 and 2510 have the same displacement they handle the same amount of power before the onset of distortion. To be safe with one cab/driver I'd go for the 2510, but with two I don't see the need.

[quote name='TheRev' post='138899' date='Feb 12 2008, 09:48 AM']I have beta 10s in my Omni 10.5s and i reckon they sound great. The general opinion over on Finnbass is that the deltalites have a more pronounced midrange compared to the Beta 10s. The Omni cab designs are quite strong in the midrange as well, so putting the two together may be too much if midrange isn't your thing... As Merton said, it's all down to personal taste but if the weight saving isn't an issue then I don't think you'll be disappionted with the Beta 10s[/quote]All things considered the Basslite S2010 is probably the best all-round choice if you're using two or more of them, with response similar to the Beta 10, displacement the same as the 2510 and the lowest weight of the three. The main problem with them in the UK is finding them.

[quote name='Merton' post='138802' date='Feb 12 2008, 07:48 AM']Thumper and Bill do disagree on this, becasue it's a purely personl choice. So I'd say screw the money consideration, do some research about the sounds of the two and choose because of that![/quote] From a technical standpoint the 2510 has higher midrange sensitivity and 147cc displacement versus 102cc for the Beta 10.

[quote name='BOD2' post='138855' date='Feb 12 2008, 09:01 AM']Thanks for that correction. It seems it's the cone movement that's the critical dimension in any case.[/quote] The technical spec is Vd, the volume displacement of the cone at full excursion, and can be found on the manufacturer's driver spec sheet.

[quote name='ped' post='137570' date='Feb 10 2008, 08:25 AM']Alex, I got the 210 because it was really cheap. I thought it sounded great - maybe it doesn't on paper, but where it matters it sounded really full and rich. It was supremely heavy though![/quote] And extremely power hungry. Basson makes a big deal about how large their magnets are and how much power they handle, which makes for good ad copy but not necessarily for a good speaker. Extremely large magnets result in lessened bass response. You end up with a cab that's twice the weight and requires four times the power to drive it than other cabs. To the OP, the 150 watt ratings of the MBC 410 drivers indicate that they're at the opposite end of the spectrum, probably entry level in quality, and chances are that cab doesn't do much below 70Hz. You don't need a cab that goes below 35Hz, but you do need one that's flat to at least 50 Hz. Unfortunately no manufacturer publishes accurate specs, so the only way to find out what works best is to try some along with your top. If your head has bi-amp capability and a built in crossover try it bi-amped with the crossover set around 125-150 Hz, using a 15" PA subwoofer cab.

[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.