Bill Fitzmaurice

[quote name='fenderiko' post='620942' date='Oct 8 2009, 03:08 PM']so why making the cab heavy ? [/quote]Because it's cheaper. Many cab manufacturers make a big deal about using 3/4" plywood, as if that's a good thing. It's not. Manufacturers use 3/4" plywood because it will give an adequate result with minimal bracing and can be assembled by unskilled minimum wage help in less than two hours from start to finish. A properly braced cab made from 1/2" plywood will be significantly lighter than a cab made from 3/4", yet it will have the rigidity of a cab made from 1". But build time will be roughly doubled, as will the number of parts in inventory, so with the overwhelming majority of manufacturers that's not how it's done.

[quote name='Mr. Foxen' post='620822' date='Oct 8 2009, 01:07 PM']Labour intensive and don't lend themselves to mass manufacture.[/quote]What they don't lend themselves to is high profit margins.

[quote name='Monz' post='620452' date='Oct 8 2009, 07:21 AM']when you get to LOUD levels the lightweights seem to loose the ability to punch the sound forward and in the case of the ultra lightweights seem to vibrate rather violently[/quote]There's a right way to build light weight cabs, which when employed will vibrate less than heavy cabs while sounding better, and there's a wrong way. One guess which applies to the lightweights you tried.

[quote name='fenderiko' post='620191' date='Oct 7 2009, 08:22 PM']why designing them so heavy in the first place ? surely people rather not lift more weight ? ? what is making then so heavy ? the wood ? driver ?[/quote] Older drivers with ceramic magnets can weigh two to four times what newer neo magnet drivers weigh. Cabs made of cheap particle board or MDF will be heavier than those made of plywood. Well braced cabs made of 12mm plywood will weigh less than poorly braced cabs made of 18mm plywood. Birch is heavier than Poplar. There are many reasons why some cabs are light and some weigh a ton. But weight alone isn't an accurate predictor of how any speaker will sound.

[quote name='muzzer' post='619506' date='Oct 7 2009, 07:52 AM']Anyway, I have done some asking around locally and there is a furniture restorer close to me who will apparently do cabinet work so I'll give hime a go.[/quote] Insist that he follow the instructions to a T, including the choice of materials and adhesives.

[quote name='alexclaber' post='618703' date='Oct 6 2009, 10:59 AM']When you cut the lows on a bass amp it's akin to cutting the gain, i.e. turning the amp down, because most of the power demands for bass guitar are in the lows. Alex[/quote]And to paraphrase Mr. Franklin a watt saved is a watt gained.

[quote name='argle' post='617964' date='Oct 5 2009, 04:07 PM']It can still sound a bit woolly at the low-end, though, presumably just by virtue of it being short-scale.[/quote] I build my own basses, and over the years transitioned to a 30" scale, as I have small hands and it's more comfortable. There's virtually no difference in the tone of my basses with 30", 32" and 34" scales.

[quote name='alexclaber' post='618581' date='Oct 6 2009, 09:20 AM']Actually you'd be less likely to clip anywhere along the signal chain if you left the 1x18" ported, plus the 18" would be less likely to run out of excursion. Alex[/quote]+1. With the added low frequency sensitivity gained by porting the 18 and the bass EQ cut more headroom is gained. The idea that flat EQ settings are of any value is intrinsically flawed, since neither amps nor speakers have flat response to begin with. The purpose of EQ knobs isn't to have them all pointed to 12:00, it's to have them set wherever they give the best result. If you can get the tone you want with the bass EQ cut by 3dB that's the equivalent of doubling the usable power from your head.

[quote name='benwhiteuk' post='617425' date='Oct 5 2009, 08:58 AM']With a poorly designed rear-ported cab there is the possibility for slight cancellation, which basically means it's gonna have a lower SPL within a certain frequency range than a front ported equivalent.[/quote]That would require that the distance from the cone on the front of the cab to the port opening on the rear of the cab be 1/2 wavelength at the cab resonant frequency. As that amounts to some 8 to 10 feet it's not a major consideration.

[quote name='waynepunkdude' post='616995' date='Oct 4 2009, 06:09 PM']I will give it a go, cheers buddy. Can I just be clear, do you mean set the left knob to about 4 o clock?[/quote]Yes, and look at the manual regarding setting the rear panel switches and running a patch cable to run Full Range/Lows.

[quote name='waynepunkdude' post='616810' date='Oct 4 2009, 03:21 PM']So will changing the fequency on the cross-over to put more of the load onto the 4X10 help?[/quote]The cabs you have aren't designed for true bi-amping. You should be running the 4x10 full range, the 1x15 lows only with the low pass filter set around 800 Hz.

[quote name='Alien' post='616584' date='Oct 4 2009, 11:27 AM']You could try lowering the crossover frequency, which would have the effect of making the 4x10 do more of the work. The biggest problem with using a standard 1x15 (or pretty much any bass cab really) as the low end in a biamped rig is that they're not really designed for it. What you need is a sub of some kind - a PA sub would do fine. A[/quote] I just assumed he was running both cabs full range. There's no point to bi-amping these speakers, though running stereo does offer the advantage of being able to power shade.

[quote name='Mr. Foxen' post='616184' date='Oct 3 2009, 10:19 PM']The watts bit is kind of irrelvant if it is your amp lighting up. Its if you are cranking the 15 side because theres not enough volume from the 15, that you need a second 15. Guessing you are running the classic 1x15 and 4x10. Probably the 4x10 is more efficient all round, so you are getting plenty from that, but the 15 is struggling to keep up.[/quote]You're quite correct. The 'classic' 1x15/4x10 is a poor match up, not just because the 1x15 handles less power but also because it has less sensitivity than a 4x10. A 1x15 works OK with a 2x10; to keep up with a 4x10 you either need a 2x15 or another 4x10.

[quote name='waynepunkdude' post='616115' date='Oct 3 2009, 06:07 PM']All the manual has is this.[/quote] That shows separate limiters for each power amp. How they function should be explained in the manual. If it isn't a conversation should be held with the amp manufacturer as to why not.

[quote name='waynepunkdude' post='616095' date='Oct 3 2009, 05:06 PM']Could it be possible that the limiter is only kicking in for one side?[/quote]That depends on how it's configured. The owner's manual should say.

[quote name='waynepunkdude' post='616064' date='Oct 3 2009, 04:18 PM']Oh the specs of my amp are: OUTPUT POWER RATING 1350 Watts Mono-Bridged @ 4 Ohms (1000 Watts Continuous) 840 Watts Mono-Bridged @ 8 Ohms (680 Watts Continuous) 2 x 675 Watts @ 2 Ohms (500 Watts Continuous) 2 x 420 Watts @ 4 Ohms (340 Watts Continuous) 2 x 255 Watts @ 8 Ohms (205 Watts Continuous) I use both power amps at 8OHMS (1 cab per power amp) my cabs are 300W & 600W[/quote] If you're lighting up the limiter it means you've reached the extent of the clean rated power of the amp. If that's not loud enough chances are your speakers are insufficient for the job, no matter what they're rated, and sending even more power to them probably will lead to a less than desirable result.

[quote name='waynepunkdude' post='616027' date='Oct 3 2009, 03:14 PM']My limiter light keeps on coming on, what will happen if I press the limit defeat button?[/quote] The light won't come on. And of course the limiter won't be functional, which increases the possibility of damaging your speakers.

[quote name='Musky' post='607645' date='Sep 24 2009, 08:09 AM']I don't think the 3012's are intended to be used in sealed cabs either.[/quote]+1. The EBP is over twice what a sealed cab wants. [url="http://www.eminence.com/resources/data.asp"]http://www.eminence.com/resources/data.asp[/url]

[quote name='Musicman20' post='605921' date='Sep 22 2009, 01:23 PM']Bill How do you rate the Bergantino Neo line...mainly the AE112? Thanks[/quote]I don't rate any lines. What I will say is that of all the dozens of bass reflex cabs loaded with a variation of the Eminence Deltalite II 2512 driver out there the AE112 is one of them.

[quote name='Linus27' post='605722' date='Sep 22 2009, 10:58 AM']600w ...should be enough.[/quote]The power output of an amp and power handling of a cab are not directly related to the sound levels you can get from them. Also, the thermal rating of the cab doesn't indicate how much power it can actually make use of. In the case of the GB 212 it might be able to take 300 watts before reaching the excursion limits of the drivers, and that's a generous estimate. So don't assume that you'll never need to run more than the 212; you're a lot better off assuming that at some point you will and plan accordingly.

[quote name='Linus27' post='604901' date='Sep 21 2009, 02:55 PM']Price is also an issue. I would look at the Genz Benz NEO 112 but they are about £500 and I believe still fairly chunky compared to other 1x12 cabs.[/quote]If you plan on using the 112 and 212 together for the big gigs the best result will come from another GB. Make sure it's twice the impedance of the 212. As to the cab size, low end output and cab size are directly related. If you compromise on the one you'll compromise on the other.

[quote name='TheBlueFalcon' post='603707' date='Sep 20 2009, 12:14 PM']If the E string on a 4-string bass is supposed to be tuned to 41.204Hz (even lower when "Low D" tuning is used or when using a 5-string bass) why are there so many cabs/combos that have 8, 10 and even 12 inch woofers that don't go below 45Hz?[/quote]Because the primary power bandwidth of electric bass starts at the 2nd harmonic, an octave up from the fundamental. The fundamental is there, but at less intensity than the harmonics until you get up around 100 Hz, where the fundamental begins to dominate. [quote]Can the difference be heard between one that "rolls off" and doesn't reproduce frequencies below 45Hz and one that is capable of reproducing the full frequency range[/quote]Yes, but the difference isn't all that much. OTOH many bass cabs, combos especially, have weak response below 100 Hz, and how they sound compared to a cab that runs flat to 50 Hz is pretty substantial. The main reason for bass cabs having a weak low end isn't the drivers, it's the cabinets, which tend to be far too small for the drivers within to operate optimally.

[quote name='nig' post='597487' date='Sep 13 2009, 11:50 AM']As far as I go back (30 years) the only info you ever needed was impedance and wattage and of course the hz frequencie for a bass speaker. please tell me more??? regards, Nig.[/quote]Here's a short list: [url="http://www.eminence.com/resources/data.asp"]http://www.eminence.com/resources/data.asp[/url]

[quote name='nig' post='597390' date='Sep 13 2009, 09:58 AM']Hi guys, has anyone a lead on where to get a replacement for my 8 ohm 12" gk neo, I usually use 2 1x12s with my RB 1001 but last nights gig was real tight on space so I used 1 cab and 10 mins from the end, smoke and then a frozen voice coil. boo hoo, so Ive mailed gk, checked out thomanns site but a uk speaker supplier would be cool, or maybe someone elses 300w 8 ohm 12" neo, thanks all.[/quote] You have to take the old driver out and identify exactly what it is in order to replace it. 300w 8ohm 12" is not sufficient information.

[quote name='chris_pokkuri' post='591084' date='Sep 5 2009, 06:15 PM']If playing with a full band (in my case 2 guitarists, loud drummer and myself) i'd say a minimum of 500w.[/quote] There are far too many variables in the equation to make a blanket statement of how much power is required. I run one channel of a Superfly into an 8 ohm 1x10 or 1x12, depending on my mood. That's only 160 watts, and I'm never wanting for more. My cabs aren't exactly off the shelf, but that's part and parcel of the variables involved. With the right cab you don't need much power, while with some (Basson, for example) you're hard pressed to ever have enough. And where output levels are concerned far more often than not power isn't the problem, inadequate/insufficient speakers to make full use of the power you have is.