Bill Fitzmaurice

[quote name='Mr Fretbuzz' timestamp='1343069408' post='1744784'] I've kept that link thanks but all I've bought are shop cables so far... The last was a retro looking Fender Custom Shop cable in the smallest length I could find as I'm told that the smaller cable you can get away with the better the signal. One thing that I've been thinking about though is that i used to get gold plated connections for my tv surround/ play station etc.... Not seen any gold plated bass ones in the shops... How come as I thought you'd get a better signal etc with them ?.. [/quote]Cables should be kept as short as you need them because longer cables are extra cost and kit that you don't need. Gold plating doesn't corrode, but unless your installation is on a boat or in a beach house that's not a concern. Overpriced/overhyped cables are the number one ripoff in the world today, don't believe 1/10th of what you see in advertising for them.

[quote name='HotelEcho' timestamp='1343049091' post='1744242'] does anyone have any preferences for speaker cables from one manufacturer over any of the others? [/quote]Copper is copper. All you want to be sure of is adequate gauge, 16 will do for 1.5m, and the use of Neutrik connectors. Since Neutriks are more expensive than generic el-cheapos if they're employed it's a safe bet that the cable is also of decent quality. [quote]I'm slightly sceptical at spending £35 on a 1.5m lead [/quote]As you should be, for that length it's at least twice what you should spend.

[quote name='bigjohn' timestamp='1342973768' post='1743305'] Nowt wrong with the speakers. Cab belonged to my mates dad from new I believe and wasn't overworked. It's then spent some year being an occasional guitar cab / stored in a studio. [/quote]It's not a matter of anything beiong wrong with them, just the fact that 50 watt fifteens of that era generally were displacement limited to perhaps 30 watts before farting out. That's a mighty big box to haul about for such a small result.

To be gig worthy you'd need to replace the drivers, brace, port and line the cab. Otherwise it would be an oversized underperforming albeit cool looking curiousity. If you or a mate have the skills to do that it might be worth the hundred, much or all of which you could recoup selling the drivers to a collector.

[quote name='bremen' timestamp='1342705117' post='1739632'] You're telling me the spiltter transformer was invented in 1980? [/quote]I doubt that, but they would not have been common items in everyone's kit. True FOH consoles as we know them today were still few and far between even in 1980. Most of what was being used through the 70s for touring was studio gear, and most of that prior to 1975 was originally made for broadcast, not live sound. Even balanced mics using XLR connectors weren't standard until the mid 70s. They existed, but most PA mixers made prior to 1975 had unbalanced 1/4" inputs.

[quote name='bremen' timestamp='1342701437' post='1739544'] Seems an odd way of going about it. Why not just use one mic, one transformer, two mixers? [/quote]Easy to say that today, in the 70s not so much. Much of what we take for granted today didn't exist then. Keep in mind that in 1970 the Shure Vocal Master was state of the art.

[quote name='BRANCINI' timestamp='1342695420' post='1739386'] They always seemed to be two different mics, rather than two the same, probably a reason for that. [/quote]If the mics are not identical the technique won't work, so if that's the case the mics are being fed to two different consoles. That was done a lot in the 70s, using one console for the FOH and the other for the recording, as most consoles then didn't have the ability to do both simultaneously. [quote]with the mics, say, 5cm apart a bit of back-of-a-fag-packet maths says that they'll already be out-of-phase at around 3300Hz, [/quote]Not if the elements are on the same plane.

[quote name='bremen' timestamp='1342538589' post='1736797'] It'd be messy to wire them in series. Easier to stick each through its own preamp, invert the phase on one, and sum them. [/quote]You'd parallel wire them into a single channel, one with the cable reverse polarity, using a dedicated Y connector to do it.

[quote name='bremen' timestamp='1342526600' post='1736527'] It's anti-feedback. They are wired out-of-phase, so sound arriving at both (ie from the PA) is cancelled out. You just sing into the one, so you don't get cancellation. [/quote]+1, a technique pioneered by the Dead, necessitated by their Wall of Sound. They didn't use monitors, rather the entire system provided both the FOH and personal monitoring as they were set up in front of it. That required the nearly 100% common mode rejection of sound that was picked up by both mics while not affecting the sound picked up by only the one mic that they sang into.

[quote name='ivansc' timestamp='1342450895' post='1735249'] Bought BF's 2x10 Jack plans, as I happen to have acquired a pair of the 300 watt Celestion Neos at a really silly price. [/quote]Be sure they meet the required specs. Watts matter little, T/S specs and response matter a lot.

[quote name='Balcro' timestamp='1342261354' post='1732424'] For entertainment / musical instrument loudspeakers it doesn't matter, but purist hi-fi people tend to design loudspeakers with the frame flush to the baffle or with a surrounding trim piece to blend the frame into the baffle. Their argument is, that it minimises unwanted sound diffractions from the sharp edges of the cut baffle board. The ultimate aim or obsession being a flat frequency response. Putting loudspeakers inside the baffle means the drive unit fires out into a 15-18mm deep tunnel, but as its for guitarists, who cares. Maybe Bill will have a technical opinion on the validity of this "hi-fi" claim. Balcro. [/quote]For our purposes it's not true. For diffraction to be significant the obstacle must be at least 1/4 wavelength in dimension; at even 4kHz that's nearly an inch, so the driver positioning on the baffle doesn't matter with electric bass or guitar. In a hi-fi cab what can happen is that a woofer frame extending beyond the baffle can cause diffraction of the wave from a tweeter adjacent to it, so inlaying the woofer flush to the baffle may be beneficial, depending how thick the frame is.

It's easier to build a front loaded cab, as the back doesn't have to be removeable. Otherwise there's no particular advantage to either arrangement.

[quote name='LawrenceH' timestamp='1341500534' post='1720115'] From a dispersion perspective I think it's better to cross as low as possible to avoid off-axis nulls due to destructive interference between drivers in the crossover region [/quote]That's much more of a concern with PA than electric bass. So long as you use at least 3rd order filtering on the midrange the response overlap zone is slight enough to minimize ill effects to the point of being virtually inaudibile, especially when compared to a typical commercial cab with woofers horizontally aligned and no midrange driver at all.

[quote name='dincz' timestamp='1341413832' post='1718602'] I suspect the answer will be no, but is there a standard for this e.g. +ve on the tip moves the cone out? [/quote]The standard is outward excursion with a positive voltage applied to the tip on a 1/4" plug or the + pole of a Speakon.

[quote name='4 Strings' timestamp='1341410777' post='1718545'] ...you mean like maple fingerboards sounding 'bright'. [/quote]Actually rosewood and ebony are brighter, being more dense than maple. More dense body woods are also brighter and sustain longer than less dense varieties. Here also there's nothing the least bit magical about it, it's simple physics. But as Clarke said any sufficiently advanced technology is indistinguisable from magic, even when that technology is as simple as a block of wood. If you're a luthier you understand the technology. If not you may not.

[quote name='dincz' timestamp='1341247347' post='1715719'] Just a thought. Correct me if I'm wrong but the potential problems with mixing cabs are to do with dispersion and comb filtering. [/quote]The main issue is the different phase responses of different cabs. When combined they may work OK, or they may not, and there's no way for the user to predict it. With identical cabs there are no issues. The theory behind mixed cabs, with tens and fifteens being by far the most popular configuration, is based on the notion that fifteens go lower, tens go higher, and that by combining them you get the 'best of both worlds'. The fly in that ointment is that fifteens don't necessarily go lower than tens, and tens don't necessarily go higher than fifteens. The only inherent difference is that tens do have wider dispersion in the mids and highs. But when tens are placed side by side their dispersion in the mids is halved, resulting in narrower dispersion than a fifteen, and the highs are combed. And where output capability is concerned one fifteen can't match four tens, so the ubiquitous 115/410 combination makes no sense from any perspective.

[quote name='Spoombung' timestamp='1341250160' post='1715783'] That sounds a bit high. I was thinking 400HZ - 1 KHZ: ie, midrange. I have a dull sounding speaker that could have more a clear midrange. It's a bit boomy. Just looking for a general pupose unit you can chain -up (link) with a bigger speaker really [/quote]There's no reason to cross lower than where the twelve starts to beam, around 1.2 to 1.6kHz. The reason for a mid driver is just as much dispersion as it is response. As for boom, that occurs down around 100 to 160Hz, so adding a mid driver wouldn't affect it. The causes of boom are a cab that's too small, is tuned too high, or is insufficiently damped, as well as a combination of any or all those factors.

[quote name='discreet' timestamp='1341243138' post='1715616'] Very good. I shall try to find out. It does mean buying another ABM and/or making another J12, though... [/quote]That's the issue, not knowing without the trying, and not having the means to do the trying.

[quote name='chris_b' timestamp='1341226173' post='1715288'] I spent the first 2 years on BC being told that mixing speakers sizes definitely never worked, when I was getting a great sound out of a mixed size rig![/quote]Show us the posts that said that. I know I never have, nor has Alex or any other qualified engineers. What we have said is that the results with mixed drivers/cabs are unpredictable, while with matched cabs you know what you'll get. [quote]How can any of us assume we know exactly how a manufacturer’s cabs were designed[/quote]Having designed many of them myself I don't have to assume anything. Designing cabs for a living I know that most manufacturers priorities are, in order of importance: 1. Profit margin 2. Graphics 3. Performance # 3 never takes precedence over #s 1 and 2. And I know that the only reason manufacturers push the concept of mixed drivers/cabs is because the average player thinks that there's some benefit to doing so. When faced with the options of saying "Don't do that" and potentially losing a sale to the next guy or giving the masses what they want, whether it's the best option or not, the almighty buck/pound is the ultimate arbitor. [quote name='discreet' timestamp='1341234575' post='1715456'] My 2p: I always believed mixed speaker sizes/ratings to be a no-no as well... seems quite logical to me, but through necessity I used an ABM 410 and a BFM J12 together at rehearsal recently and I have to say it sounded extremely immense - and that's the bottom line, isn't it? [/quote]Virtually any two cabs together will sound better than either alone. What you don't know is whether you'd have had a better result with two ABM410 or two J12.

[quote name='Lozz196' timestamp='1341097827' post='1713916'] Agreed. But a 212 mathematically is the same area as 310 (well about 98% if I remember correctly). [/quote]That depends on the displacement of the individual drivers, and by no means are all tens the same, nor twelves, or any other size.

[quote name='Lozz196' timestamp='1341078287' post='1713645'] Surface area wise, a 212 is virtually equal to a 310, in the amount of air being pushed - [/quote]Surface area doesn't matter. http://barefacedbass.com/technical-information/Volume-displacement.htm

[quote name='Lord Sausage' timestamp='1341072360' post='1713535'] i asked about what the frequency response of the cab was. He didn't know what it was, or meant i think, then went and looked it up on the internet.[/quote]That's part of the problem. Then there's the manufacturers, who not only don't discourage the false notion that a 1x15 can go lower and/or as loud as a 4x10, they foster it. Why? Because that combination sells. Whether it works well or not doesn't concern them.

[quote name='Fubar' timestamp='1340993260' post='1712661'] This has the effect of making the cab 'think' it's bigger than it really is. [/quote]Myth, though a very widespread one. Sufficient stuffing will lower the Q of a cab, which can tame boom, which is [i]similar [/i]to the effect of a larger cab. But it's not the same, as a larger cab also gives lower response with higher sensitivity. And you only stuff a sealed cab, never a vented cab. Stuffing a vented cab will upset the box tuning.

[quote name='PlungerModerno' timestamp='1340882658' post='1710938'] Seems legit. If I was marketing a new cab, esp. a sealed cab... and wanted to show it could produce lots more lows at less watts than most sealed cabs... I'd give a chart because that'd be the hardest thing to argue against. [/quote]You'd think, but what would you compare it against? The major problem is that the response of most bass cabs drops off around 80Hz. That's normal. The expectation of users is that they should be flat to 40Hz or lower. No manufacturer wants their response charts to reveal that their cabs don't meet that expectation, so they don't make charts available. Most manufacturers also quote sensitivity measured in the vicinity of 1kHz, where it doesn't matter, instead of 100Hz, where it does. SPL charts would reveal the truth, a truth that they don't want revealed. What is the truth? Have a look: http://billfitzmaurice.info/forum/viewtopic.php?f=12&t=2357 http://billfitzmaurice.info/forum/viewtopic.php?f=12&t=2362 http://billfitzmaurice.info/forum/viewtopic.php?f=12&t=2374

[quote name='Lord Sausage' timestamp='1340822579' post='1710188'] So what region should you be looking for in SPL charts [/quote]First you have to find them; AFAIK no one reveals them. The official reasons why are 'we don't want to confuse players with information they might not understand (calling you stupid they are) and 'people buy our cabs based on how they sound, not how they chart'. But they don't explain how people are supposed to know how they sound before they buy them if they can't try them first. The real reason for there being no charts is either they don't want you to see them, or they don't have any. Or both.