Bill Fitzmaurice

[quote name='Chadderz' post='955252' date='Sep 13 2010, 02:32 PM']. My question is, therefore, will an extra cab increase the available volume?[/quote] An identical cab will increase output by 6dB. That's the equivalent of a quadrupling of power. [quote]Classic stack for bass with plenty of power - 1x15 & 4x10.[/quote]Classic and popular, but a poor match up. If one must mix drivers a 2x10 and 1x15 are a far better match. Keep the impedance of the two the same.

[quote name='markstuk' post='952798' date='Sep 11 2010, 10:20 AM']Can we start on XMAX and VD soon? :-)[/quote] VD is what you can catch if you're not careful about with whom you canoodle at the IMAX.

[quote name='munkonthehill' post='952141' date='Sep 10 2010, 01:58 PM']so what do I get in comparison of the 350watts and 500watts then?????[/quote] 2dB. To sound twice as loud requires 10dB. That's the difference between 350w and 3500w. And that 2dB is best case, assuming your speakers can make use of the additional power. Between thermal and mechanical power compression few speakers can actually make use of more than half their thermal wattage ratings, and most come in closer to 40%. So the answer might be no difference.

[quote name='Stylon Pilson' post='952090' date='Sep 10 2010, 12:57 PM']To the OP - if you do succeed in this, then prepare for somewhat disappointing results. S.P.[/quote]He should be prepared for total disappointment. Watts and volume are not directly related.

[quote name='largo' post='948086' date='Sep 7 2010, 05:56 AM']Or, is this 4 ohm cab simply a myth that most people make too big a deal of.[/quote]Myth. It arises from the assumption that sound levels and power levels are linear with respect to each other. They are not. Sound levels are logarithmic with respect to power; ie., it takes ten times the power to sound twice as loud. That being the case the roughly 70% power increase seen with a 4 ohm load versus 8 ohm load doesn't make a significant difference.

[quote name='btp' post='942902' date='Sep 1 2010, 07:50 PM']I was actually looking at the Eminence Legend BP102 -- they have a really low Fs (35Hz), high xMax, but a little less power handling, a little heavier, but MUCH cheaper... two of them would cost the same as one Celestion, if I could even locate one...[/quote] BP102s are great drivers at a low price, but they aren't good full range. Crossed over to a 6 inch mid no worries.

[quote name='btp' post='939735' date='Aug 29 2010, 08:47 PM']I've got a cabinet loaded with 2 Celestion BN10-300x -- it's a 3-way Dr. Bass 2060 slant face, with a 6" eminence mid and a selenium tweeter.[/quote] With the mids afforded by the 6" mid using high Fs tens is a very odd choice. I'd be looking at replacing them with long excursion tens with Fs between 35 and 45 Hz. Eminence will have some in the yet to be announced 3010 series, but those being at least 6 months down the road, perhaps a year in the UK, I'd look around for alternatives if you don't want to wait.

[quote name='velvetkevorkian' post='939699' date='Aug 29 2010, 06:55 PM']Speculating somewhat, but maybe this is down to mass; i.e. to make a recognisable neck shape requires quite a large mass of solid material, whereas on a cab you could use much thinner sheets (rather than 3/4" plywood or whatever) because graphite/composites are much stiffer per unit of mass. I'm prepared to be shot down in flames though. [/quote] You're on the right track. If a carbon fiber neck is solid it's flawed, as that doesn't take advantage of the stiffness of the material. It should be semi-hollow, consisting of multiple small chambers. But that entails a very high initial tooling cost. That's not as much concern with tennis rackets, which probably outsell electric basses by about a 10,000:1 ratio. Probably the best material for a bass cab would be carbon fiber honeycomb matrix. It works well enough in F-117s. But it ain't cheap, especially since most of it is gobbled up by the aerospace industry.

[quote name='Grant' post='939607' date='Aug 29 2010, 04:16 PM']But has anyone tried making bass cab enclosures with this stuff?[/quote]It's been done with PA, the cost verges on astronomical. Bass players being the cheapskates...excuse me, 'thrifty blokes' that they are, I doubt you'll see carbon fiber bass cabs successfully marketed.

[quote name='Jesso' post='934461' date='Aug 24 2010, 04:25 AM']So in most cases the audience may not even see the subs at all? They could be behind the stage, or off to the side, where ever there is a wall?[/quote]Yes. The output of subs is omnidirectional, so there's no need to see them. That's quite the opposite of tops, which are very directional. Dispersion and boundary loading characteristics below 100Hz versus above 100 Hz are completely different, so much so that if your subs and tops are in the same room location chances are about 20:1 that the results will be compromised, often severely so.

[quote name='Jesso' post='934302' date='Aug 23 2010, 06:21 PM']Thanks for answering. I have heard several times that it's better to place the subs together, but from an asthetic and stability point of view, Jesse[/quote]The choice is simple: do you want to look good or sound good? Where subwoofer placement is concerned more often than not it's a distinct choice between the two. [quote]Wouldn't putting the subs to one side of the stage be strange from a sound point of view?[/quote]No. Neither should they be away from walls, neither should they be pointed at the audience. This is admittedly all counter-intuitive, but the field of acoustics is very much counter-intuitive. Proper versus improper sub placement can account for as much as a 24dB difference in output. That's the equivalent of 10 watts versus 2000 watts.

Clipping is never good. It doesn't really bother the amp but will sooner or later toast the driver if the amp is capable of pushing the driver past either its thermal or mechanical limits. I'd be willing to be that you have the subs incorrectly placed, ie., split to either side, beneath the tops. Most operators do it that way, as subs don't come with placement instructions. Worse still are those with pole sockets that encourage that placement. The right way is explained here. The link specifically refers to horns, but all subs adhere to the same rules of placement. [url="http://billfitzmaurice.info/forum/viewtopic.php?f=1&t=398&sid=3fb065f1be520fc61efeaf0adcd7ddea"]http://billfitzmaurice.info/forum/viewtopi...efeaf0adcd7ddea[/url]

[quote name='Wil' post='923764' date='Aug 13 2010, 07:57 AM']Now, the Schroeder is rated to something like 1200 watts, so it should be able to cope with everything my head can throw at it, right?[/quote]Thermal ratings aren't worth diddly. A realistic displacement limited power rating for the Schro would be 300 watts.

Check out the Headcase at [url="http://www.talkbass.com/wiki/index.php/Fearful™_12/6_%26_15/6"]http://www.talkbass.com/wiki/index.php/Fea...™_12/6_%26_15/6[/url] Whatever you do don't duplicate or even imitate the Trace. It had the drivers horizontally placed, which should never be done.

[quote name='Machines' post='909507' date='Jul 29 2010, 01:16 PM']You bought an Ashdown for something more reliable ? Hahahaha... think of Ashdown as the bass equivalent of Alfa Romeo.[/quote] Does Alfa use Lucas Lighting? In college we always bought MGs in pairs. One to drive, one for the shop.

[quote name='3V17C' post='909247' date='Jul 29 2010, 09:02 AM']yeah could do that.. was just thinking that i won't get the full 575watts then though with an 8ohm cab on each ?....[/quote] Moot.

[quote name='Shire' post='901067' date='Jul 21 2010, 11:51 AM']the smaller the better and my band play loud![/quote]And there's the rub. Where loud bass is concerned there's no replacement for displacement, and that means big cabs, not small. The only way to get around the need for many drivers is with fewer high displacement drivers, like the Eminence 3012LF and 3015LF as used in Barefaced. What you trade off there is sensitivity, so what you achieve in going smaller is done at the expense of needing more power. Your amp should do for them, though.

[quote name='3V17C' post='908906' date='Jul 29 2010, 04:18 AM']I'm guessing its fine to just use one power stage with two 8 ohm cabs (thus making 4 ohms) and leaving the other power stage unconnected will be fine?[/quote] I'd run a cab with each amp. That way the current load is shared by both power amps rather than being a burden to only one.

[quote name='fatgoogle' post='908549' date='Jul 28 2010, 02:11 PM']Yep you want 16ohms. It means if both drivers are 150 watts youll get a 300 watt cab while 4 ohms wired to 8 means youll only have a 150 watt cab. I think this is right anyway.[/quote] 150 + 150 equals 300, series or parallel. What differs is the voltage and current division, not power. As to 4 ohm drivers series versus 16 ohm drivers parallel, there will be very little difference electrically. There can be a major difference mechanically, due to different voice coil lengths. You want to use the option that has the higher xmax and xlim specs.

[quote name='dannybuoy' post='904778' date='Jul 25 2010, 10:03 AM']I didn't know the actor who played Jesus in Passion Of The Christ got struck by lightning twice on set[/quote]I'm wondering what he did to so piss off God, and why God's aim is so poor to have missed him twice!

[quote name='Mark Percy' post='904338' date='Jul 24 2010, 04:34 PM']speakon connectors have greater surface area connectivity as opposed to phono jacks. thicker cables, like 4.5 have less resistance than thin cables.[/quote] Use Speakon, yes. But no one uses phono jacks for speakers anyway. For the lengths we use to connect amps and speakers wire more than 14ga/1.9mm is a waste of copper, and money. Here again your post is rife with errors. I don't know who you're trying to impress with all these posts full of piffle, other than yourself, but IMO they're a total waste of board bandwidth.

[quote name='Mr. Foxen' post='903695' date='Jul 23 2010, 07:46 PM']compiling a huge amount of wrong into a single essay is weird.[/quote]Clearly you are unfamiliar with Glenn Beck, Rush Limbaugh and Sarah Palin, who have made doing just so into a very comfortable living.

[quote name='redstriper' post='903476' date='Jul 23 2010, 01:45 PM']He did not say anything about the cab AFAIK - he said "blasted low/mid sound that all neodymium speakers have". That statement is simply wrong, it may have prompted a pontless change of driver and certainly would put anybody off neo drivers. It's the kind of blanket BS that gives sound engineers a bad name and if it wasn't for this forum the OP would still believe it.[/quote]+1, and since the majority of high end pro-touring PA cabs have been loaded with neo drivers for over a decade now it's hardly an understandable gaffe.

[quote name='Mark Percy' post='903463' date='Jul 23 2010, 01:31 PM']new power piston high wattage drivers are wholly unsuitable, and require vast wattage headroom to get them moving. and are insensitive and unmusical.[/quote] Totally unequivocally untrue, as is the rest of your post. Nothing said has any basis in engineering fact, I'm afraid.

[quote name='Mr. Foxen' post='901725' date='Jul 22 2010, 06:00 AM']there are a whole bunch of other properties that are a whole bunch of other properties a speaker will have, and will have changed.[/quote] There are a number of properties that [i]may[/i] be changed with neo, because the smaller motor structure allows it. But they don't have to be changed. Transducer engineers are quite capable of making neo drivers that precisely duplicate the response of ceramics; the fact that for the most part they don't do so is because they don't [i]want[/i] to. My friends in the engineering dept. at Eminence are totally pleased with neo because it allows them to do things they always wanted to do with ceramic but couldn't, the main difference being longer throw capability, allowing more low frequency output.