Bill Fitzmaurice

[quote name='Mr.T' post='828431' date='May 5 2010, 08:46 AM']Would 60 litres be classed as a 'small' cab for a 12" driver? They are a similar size to the Aggie 12's, and I don't hear too many people complaining about a lack of low-end from those. But hey.... Horses for courses![/quote]60l is adequate for twelves with Qts of .4 or less. As for the perception of low end response, the human ear is very inaccurate; most people are about an octave low in their estimates of the frequency they're hearing. Low 'B' players who swear they're knocking down walls with 32Hz output are actually hearing the 2nd harmonic at 64Hz. Good thing, as otherwise even a Fridge wouldn't be up to 5 stringer needs.

Eminence has been using Klippel Analysis to measure xmax on their drivers for about four years. It's defined as excursion at 10% THD. It's a far more valid method than coil depth/plate thickness methods, which are neither accurate nor consistent. For instance, in the case of under-hung coils that method gives an xmax of zero. Comparing the Klippel versus coil/plate figures on Eminence drivers the Klippel figure runs about 15% higher. Using that standard the BN10300S would come in around 2.5mm, and the NTR-10 2520D around 4.9mm. As to why Klippel is not universally employed it's simply a matter of the manufacturers not buying the gear.

[quote name='JTUK' post='825908' date='May 2 2010, 04:23 PM']Well, crap gear back then was crap gear..we all prorbaly had it at some time. Got to disagree with the stack influence factor though... Same rig, different room has had a massive effect on my sound from time to time. That is why I say it is a bigger influence.[/quote] Room modes are problematic for sure, but one way to minimize their effect is with vertically aligned drivers, which have far more uniformity from room to room, and basically just sound better no matter what room you use them in.

[quote name='JTUK' post='824144' date='Apr 30 2010, 10:25 AM']because most of us would run a mile from having to revert back to the old PA columns for bass. [/quote]In the late '60s I used a Kustom Tuck and Roll 4x12 PA column, it had as much output as a Fridge, with better tone to boot. [quote]It just looks total cack... and I'd be thinking the variable of the room has far more influence between sounds than how you stack them.[/quote]And that's why no one sells them. How you stack them has more influence over the sound than the room. Your not knowing that isn't the exception, it's the rule, unfortunately.

[quote name='Badass' post='822775' date='Apr 29 2010, 05:17 AM']Anyone else do it the way described by GK?[/quote] Not me. I set my gain for the desired level of grit, then I set the master for the desired level. It tends to be the other way around with a PA console, where you want it as clean as possible.

[quote name='chris_b' post='821170' date='Apr 27 2010, 04:02 PM']Isn't Bugera and Behringer part of the same company? Nuff said![/quote] Bugera is the silly quasi-Italian name that Behringer pulled out of thin air to stick on musical instrument amps, so that the ill-informed wouldn't realize it was Behringer until it was too late.

Go either two 2x12 or two 3x10, in both cases with cabs that have the drivers vertically aligned. Use one at smaller gigs, two for the big gigs, and then with the two cabs vertically stacked. The result is far better than either a 4x12 or 6x10, and a much easier haul.

[quote name='muddymesser' post='806720' date='Apr 14 2010, 06:39 PM']hi i'm just starting out and cant afford to buy an amp just yet but i have the leads and adaptors ready for when i do but i was wondering if my bass would work ok if i plugged into my car radio as it has an aux in port on it and is connected to a 400w amp and sub ? cheers ben[/quote]Aux inputs are line level; an active bass might work, a passive probably won't. And fitting the car on stage might be a deal breaker.

[quote name='mikeselfinflicted' post='784174' date='Mar 23 2010, 07:35 PM']Thanks you given me alot to think about maybe i could trade them in an find an ashdown ABM 8x10!!! guitarists get it so much easier its not fair!!!! :snob:[/quote]If loaded with the same drivers it will be but more of the same result.

[quote name='Toasted' post='784125' date='Mar 23 2010, 06:55 PM']I have no idea why anyone would tell you that you need a power conditioner unless they were trying to sell you one.[/quote]+1. The only proponents of power conditioners are those who make them, those who sell them, and those who believe the sales pitches proffered by same. For a more unbiased view ask any amp manufacturer if their amps should be used with one. Not one will say 'yes'.

[quote name='mikeselfinflicted' post='782645' date='Mar 22 2010, 03:40 PM']Hi i'm thinking about changing the speakers in my cabs. i'm running 2 4x10 ashdown MAG cabs but the speakers just don't seem to cut it, i've been told the voicing of the cabs is pretty good but the speakers are lame so i was thinking of changing over to eminence BP102's.[/quote] BP102s will take a lot of power in the low end but they're very weak in the mids; I only use them along with a midrange driver. I believe Ashdown uses Sica OEM drivers and that they aren't of very high quality. With eight of them you don't need a huge power rating, so the Eminence Basslite S2010 should be a good bang for the buck driver and they do sound very good. They also weigh almost nothing.

[quote name='Reissueplayer' post='780438' date='Mar 20 2010, 02:23 AM']I've just bought a TC Staccato and I'm considering their cabs as well. I've seen the cabs stacked vertically and I really like the idea of combining easy transportation, flexibility in placement and the thought of getting both ground contact as well as definition from something closer to the ears. Is there anyone on the forum that has tried and experienced this? What is the sound dispersion like? How do they compare to a 4x10 cab on the ground? Should I go for two RS210s or combine an RS212 with the RS210?[/quote] Two RS210s will be subjectively far closer to an 8x10 than a 4x10, only it will have twice the midrange dispersion angle of either. Mixing a 212 and 210 will offer little benefit, if a ten doesn't go low enough for you it will take at the least fifteens, if not eighteens, to make a substantial difference. OTOH twelves vertically aligned have far better midrange than tens horizontally placed, so if you need the power of an 8x10 on occasion get a pair of 212, leave one at home when you don't need that much.

[quote name='Finbar' post='774835' date='Mar 14 2010, 08:36 PM']Okay, on my old QSC power amp, I had a 30/50Hz filter to block out all the extreme lows from reaching my cab and effectively making the cab more efficient. I'd be interested to see if something to filter out those frequencies would make a difference. I have a small crossover I can try this with to see if the concept works, but where does it actually need to go? If I put it after my pedals but before the amp, would this be enough, or are these frequencies actually generated in the amp itself, even if it isn't fed a signal below 50Hz? If the frequencies are generated in the amp, then how would I go about stopping them reaching my cab?[/quote] It's not a matter of efficiency, it's a matter of not sending to the speakers frequencies that they can't do anything with, which just muddies up the works, mainly string thump noise. Sub-sonics are not created by the amp. Most bass amps have high-pass filtering built in, so adding another level of filtering might not make much difference. Worth a try, though.

If you've got an 8 ohm 4x10 that's probably 8 ohm drivers wired as series/parallel pairs. Open it up, add another speakon and wire each parallel pair to its own speakon, that's two 4 ohm loads, drive each with one of the Superfly power amps. Pay attention to polarity.

[quote name='Basska' post='764096' date='Mar 4 2010, 11:24 AM']what does programme mean?[/quote]It means the marketeers are diligently at work, whereas engineers only consider RMS/continuous.

[quote name='Mr. Foxen' post='762375' date='Mar 2 2010, 06:05 PM']Anyone know what the equivalent to those old 32ohm drivers in the first 8x10s is?[/quote] Jensen Mod 10s.

[quote name='Protium' post='760813' date='Mar 1 2010, 10:15 AM']Then why not give some constructive advice instead of taking the usual "no-one else can make loudspeakers" stance?[/quote]I did. I sent him to a site that explains in great detail the hows and whys of building speakers, including free plans for cabs that are better than 99% of the commercial cabs made. That's assuming that Alex hasn't yet breached 1% market share.

[quote name='jmsjabb' post='760498' date='Mar 1 2010, 05:28 AM']Wow, if we all had your encouragement in life, no one would learn anything for them selves or have fun in learning. What a pessimistic post Go for it, as said, find a cab you like. Measure it and build it. B&Q will even cut the wood if needed. Arm your self with some gorilla glue, and have fun! Sometimes science is not the important thing. Sense of achievement and pride counts. If it sounds good to you at the end of the day, job WELL done. If not, change something and try that.[/quote] That's easy advise to give when it's the OPs time, and money, that's being wagered on the result.

[quote name='Mr. Foxen' post='760362' date='Feb 28 2010, 08:22 PM']Fairly sure Wayne is going to be the next Alex Claber, so be afraid of the competition. The 5 or 6 fearful threads are fairly interesting reading. They do end up looking a lot like 'The Big One'. Critical analysis of post please?[/quote]The resemblance between Greenboy's and Alex's cabs is far more than cosmetic. Both buck the standards of cabs from the usual suspects in that they adhere to rather than ignore valid acoustical engineering tenets.

[quote name='waynepunkdude' post='760175' date='Feb 28 2010, 04:27 PM']Cheers mate, I'm a little unsure what all of that means if I'm honest.[/quote] And that's why you should not consider designing your own cab, or even choosing your own drivers for that matter. It's far more involved than it appears. For a beginner this is probably your best route, albeit a long one: [url="http://www.talkbass.com/wiki/index.php/Fearful"]http://www.talkbass.com/wiki/index.php/Fearful[/url]

[quote name='Ancient Mariner' post='758904' date='Feb 27 2010, 05:02 AM']I'm trying to use winISD for a speaker not listed in the database. There are some required parameters that I cannot find out for the speaker (a celestion BL12 100) and the program keeps locking up. Any ideas what I can do? Thanks[/quote]Let the program calculate them for you. Only enter Vas, Qes, Qms, Fs, Sd, Re, Xmax, Le, Pe. It will take care of the rest.

[quote name='tom skool' post='757243' date='Feb 25 2010, 11:27 AM']I do have a splitter box ( wired for either series or paralell) Could i use that somehow? have both cabs plug into the box and then run a lead from the box to the amp?[/quote] That should work fine. You could also try it with the cabs in series into the 16 ohm tap, you never know. Cabs in series tend not to work all that well, but it's worth a shot.

[quote name='tom skool' post='756829' date='Feb 25 2010, 05:12 AM']hi all I have got an old valve amp which has got one 8ohm output and one 16ohm output. Is there any way i can attach more than one cab for a bit more oomph? I'm guessing putting an 8 ohm cab to the 8ohm out and a 16 ohm cab to the other wouldn't be right for some reason.[/quote] The taps on a valve amp represent the maximum load that should be used with them, the opposite of SS amps. You can daisy chain cabs no problem, just make sure both cabs have the same impedance. A pair of 8 ohm cabs daisy chained is 4 ohms, so run them off the 8 ohm tap. The 16 ohm tap is pretty much of no value, as 16 ohm and higher cabs are no longer to be found.

[quote name='skankdelvar' post='754343' date='Feb 22 2010, 03:39 PM']A ground lift disengages the amps electrical earth.[/quote] Not quite. Amps of that era had no direct chassis connection to ground, as they used a two-wire connection to the mains. To provide noise filtering they connected the chassis to the ground wire via a capacitor. The problem lay in knowing which of the two wires was connected to hot and which was ground, as the plugs and outlets were not polarized. The ground switch toggled the connection through the cap from one wire to the other. When you powered the amp up you listened for noise and switched the ground switch to the quieter position. Of course when in the wrong position the chassis was connected to the hot wire, but since it was via a cap in the .1uF range it didn't get a full 60 Hz signal, just the higher harmonics. If you touched the chassis or anything connected to it, like your bass, and something that was grounded, like a mic, you'd get a benign but unmistakable reminder of why one should not play an instrument whilst bathing. The ground lift switch on modern gear lifts the ground from the signal direct out, not the chassis to mains ground. [quote]I had some work done on it a few years ago so the switch might have been by-passed but I cant be certain. Ill get it checked out[/quote]. If converted to UK power it should have a 3 wire connection, grounding the chassis and eliminating the ground switch. Unfortunately that would lop a few hundred quid off its value to a collector.

[quote name='Musicman69' post='754115' date='Feb 22 2010, 12:46 PM']Hi Folks, This is my old Bassman head, I bought it in 1980 for 50 punts (with cab) Just thought Id put up pics and maybe someone here might know its age. Looks very '60s to me. Any info appreciated.. thanks. John [attachment=43321:Bassman1.gif] [attachment=43324:Bassman2.gif][/quote] Take a look here: [url="http://www.ampwares.com/"]http://www.ampwares.com/[/url] It appears to be a 61-62, and it might be worth about 100 times what you paid for it.