Bill Fitzmaurice

[quote name='Moos3h' post='1034209' date='Nov 23 2010, 01:48 PM']I'm SURE there must be a reason why this can't be done?[/quote] The same reason one doesn't fill the boot of their auto with concrete so that they might get all of the horsepower out of their engine. You'll use a lot more gas but you won't go any faster. I believe the subject is addressed in the FAQ.

[quote name='LawrenceH' post='1034111' date='Nov 23 2010, 12:15 PM']I honestly can't see what's at all controversial about the idea that porting is used to boost low-end output of speakers but comes with its own set of compromises and complications, and if it wasn't necessary to boost LF volume output we wouldn't use it.[/quote]There's nothing controversial about it, it just isn't true. One doesn't properly use a sealed versus ported alignment for any reason other than the specs of the drivers employed and the results desired. [quote]With sealed cabs you get a nice gentle drop in frequency response that is much more easily matched with a simple shelving filter than the more complex rapid drop (with small hump or shelf) associated with ported cabs[/quote]One can obtain the same results with either topology. And one can obtain totally different results with either topology. One just has to know what one's doing.

[quote name='4 Strings' post='1033517' date='Nov 23 2010, 03:48 AM']So, it seems I'm not going to improve things too much by changing the driver but might do so with adjustments to the port. Bit difficult to tell if the port is 'chuffing' or the speaker complaining. Assuming we do have 'chuff', what to do? There's not really space to make the port larger in diameter, what if I made the tube longer? How long would be best? What if I made another 3" port (say, in the back). What length tubes would be best?[/quote]Catch-22. A 3" port is too small in diameter to not chuff. A 4" would probably relieve the chuffing, 5" is better, but both require far longer ducts. The larger duct volume subtracts from the net cabinet volume, which raises the cabinet tuning and leads to boomy response. IMO you have a nice driver deserving of a new home. I wouldn't invest any more in the old one.

[quote name='LawrenceH' post='1033133' date='Nov 22 2010, 03:06 PM']hence the 'loudness function'[/quote] That is intended to address the issue of equal loudness. To do so it boosts both the lower and upper end of the spectrum when the volume pot is set at low levels, with the effect diminished as volume is increased.

[quote name='LawrenceH' post='1033098' date='Nov 22 2010, 02:35 PM']Bill has again decided to obscure my point entirely by saying that if 'sealed was superior then that's what would dominate the market'.[/quote] By the market I meant speakers in general, not just electric bass. In home use output isn't the concern that it is with pro-sound, and yet ported still dominates every segment of the hi-fi market save one, HT subwoofers. There sealed is well represented for two reasons: cabin gain and high driver Qts.

[quote name='LawrenceH' post='1033024' date='Nov 22 2010, 01:32 PM']I do wonder though, how many people actually regularly listen to bass on decent sealed systems, monitors, hi-fis or cabs? We're probably more used to adapting to ported cabs. I can't use sealed cabs as an effective solution for compact bass cabs due to the loudness issue, but they are very revealing. Perhaps too much for some people.[/quote] Is sealed was actually superior then that's what would dominate the market. I agree that poorly designed and built ported speakers sound like crap, but that's because they're poorly designed and built, not because they're ported. As to the quoted article, not much there to impress. Especially this :[i]"The classic Yamaha NS10 is too, and while its overall frequency response isn't quite as refined as that of the LS3/5A, its time domain precision enables it to provide superb clarity and separation of the bass elements in a mix, which is partly why it has been such a popular studio reference for decades."[/i] The real reason for the popularity of the NS-10 was its resemblance to the consumer speakers that average listeners would be using. It was always said that if you could get a mix to sound good through NS10s it would sound good through [i]anything[/i].

[quote name='4 Strings' post='1032011' date='Nov 21 2010, 05:35 PM']I read somewhere about the K-200 having a low Qts reduces its bass response. I don't know what that is.[/quote]True, although that's offset somewhat by the low 35Hz Fs. You can get more low end out of a driver with higher Qts, but not in a 1 cu ft box.

[quote name='LawrenceH' post='1032100' date='Nov 21 2010, 06:53 PM']And regarding tone, if loudness weren't an issue most designers wouldn't even use porting.[/quote]Not any designers I know. There's nothing the least bit magical about sealed cabs. Most cabs in the 60s were sealed not because they sounded better but because most of the drivers available didn't work any better in vented alignments. Designers/manufacturers who still create sealed cabs don't do so because they're better, they do so because they sell, mainly to customers who think there's something inherently better about the tone of a sealed cab. The fact of the matter is that a good designer can precisely duplicate the transfer function of a sealed cab with a vented alignment.

[quote name='ThomBassmonkey' post='1031923' date='Nov 21 2010, 04:24 PM']I've looked through this thread, but I can't see specifically what the problem caused by horizontally placed speakers is.[/quote] Dispersion is inversely proportional to the dimension of the radiating plane. Horizontal dispersion of two drivers placed horizontally is half that of two drivers placed vertically. Explained in great detail here: [url="http://www.gtaust.com/filter/06/08.shtml"]http://www.gtaust.com/filter/06/08.shtml[/url]

[quote name='4 Strings' post='1031039' date='Nov 20 2010, 07:11 PM']Turns out the current driver is a Beyma K-200, not familiar with it myself. Has a huge magnet but no impedance marked.[/quote] The 12K200 is a premium driver. There's nothing wrong that putting it into a well designed and built cab wouldn't cure.

[quote name='TimR' post='1030968' date='Nov 20 2010, 05:57 PM']How loud does an 8x10 'sound' compared to a 4x10 vertical stack?[/quote]That depends on the 8x10 and vertical 4x10 in question. Some vertical 4x10s have higher sensitivity and displacement limited output than some 8x10s, especially sealed 8x10s. This is a maximum SPL plot of an SVT (blue) and a pair of 3 cu ft ported 2x10s loaded with Deltalite II 2510s (red). Where power/output demands are highest, from 41 to 65 Hz, the pair of 2x10s are louder.

[quote name='4 Strings' post='1030142' date='Nov 20 2010, 03:53 AM']The cabinet is around 13cu in (ie about 14 x 14 x 12)[/quote] That comes down to about 1 cu ft net, and no driver is going to give [i]"plenty of bass in it to get an deep tone, which can go nice and deep"[/i] from a box that small. IMO it's not worth replacing the driver, put the money in a better/larger cab, used if $ is an issue.

[quote name='TimR' post='1026762' date='Nov 17 2010, 06:54 AM']I wouldn't mod the amp. I would build a box to sit on the amp that provided the 9v and had two 1/4" sockets.[/quote]The entire point of phantom is simplicity, which a separate box isn't. Someone with the chops to rightfully consider doing this isn't the least bit daunted at the prospect. I've run phantom for 30 years and never had a problem. Or a dead battery.

[quote name='dincz' post='1026042' date='Nov 16 2010, 11:41 AM']That's what I have in mind, but my only concern is the use of a standard connector which would allow accidental connection of standard gear/instruments that might be damaged or that might damage the power supply.[/quote]That would happen if somebody plugged a mic into your amp. A four conductor XLR would remove that possibility, as they're hardly used for anything anymore. So much so that they might be hard to find.

[quote name='dincz' post='1024238' date='Nov 15 2010, 01:43 AM']I'm thinking of modding my amp and bass to provide 9V for the onboard preamp and so avoid the problems that go along with batteries. It should be simple enough to do, so I wonder why manufacturers of amps and basses don't already offer this feature. Or do they?[/quote] It's simple, use an XLR at either end, tap into one of the pre-amp's positive rails. If the on-board will take more than 9v you can get additional headroom, but if not use a 9v voltage regulator. Be sure to filter the supply at the bass end. The advantage is never having a dead battery. Be sure to retain the 1/4" at both ends and back-up battery on board in case you ever need them. Manufacturers don't offer this due to compatibility issues.

[quote name='Conan' post='1025729' date='Nov 16 2010, 07:19 AM']Do we hear what we want/expect to hear?[/quote][url="http://www.youtube.com/watch?v=BYTlN6wjcvQ"]http://www.youtube.com/watch?v=BYTlN6wjcvQ[/url]

[quote name='thisnameistaken' post='1025404' date='Nov 15 2010, 08:25 PM']If you say that two twelves stacked vertically would be better than what I've got now.[/quote]Not better, different. Whether that different is better or worse for you only you can judge. But to say that if one's using four tens that the only way it should be done is to put them into a typical 4x arrangement is to ignore an alternative that most players who have actually tried prefer.

[quote name='Stewart' post='1025306' date='Nov 15 2010, 06:00 PM']- why would you NOT want to do that?[/quote] There are two primary reasons why things are done as they always have been: 'It's how we've always done it' and 'It's the only way we know how to do it'. Those who open their minds sufficiently to allow for alteration of the latter don't have to forever conform to the former.

[quote name='Mog' post='1025136' date='Nov 15 2010, 03:16 PM']Its just for monitoring for the guitarist as some of the stages can be very wide. Maybe 18-20 feet between stacks. I only run a 150 watt head so theres not much chance of bleed into the FOH feed. Loads of power IMO. Even in medium sized clubs the PA does all my grunt work. I'm not into the whole 1k bass head thing. Just dont get it?[/quote] Put one cab on the floor aimed at the guitar player. What he can't hear are your directional mids, and with your extension placed below his it's not doing much good there anyway, most pass him by at the knees. Put the other cab atop the first, aimed at you.

[quote name='Mog' post='1024716' date='Nov 15 2010, 10:08 AM']One for each side of the stage[/quote] Spreading cabs is a very bad idea. This explains why; it specifically addresses PA sub placement, but the same rules apply to electric bass. [url="http://www.prosoundweb.com/article/in_search_of_the_power_alley/"]http://www.prosoundweb.com/article/in_sear...he_power_alley/[/url] As for what you need, the job of backline is to handle the stage. I wouldn't dream of playing to more than 300 seats without full PA.

[quote name='Conan' post='1024298' date='Nov 15 2010, 04:19 AM']In many cases, isn't it simply that people prefer what they are used to? Anything that sounds different - even if it is technically "better" - sounds "wrong" to their ears?[/quote] Most players buy with their eyes, not their ears. What's the number one comment made about new gear? [i]That looks good, I need to have one![/i] The contents of this video says much about how the eyes tend to overrule the ears. Pay particular attention to the 'tube amp versus SS amp switch' experiment. [url="http://www.youtube.com/watch?v=BYTlN6wjcvQ"]http://www.youtube.com/watch?v=BYTlN6wjcvQ[/url]

[quote name='Jean-Luc Pickguard' post='1022818' date='Nov 13 2010, 02:32 PM']having a cab braced up to its eyeballs won't stop people from stumbling into things.[/quote]Agreed, that's where having a cattle prod handy works a treat. My drink is welcome atop my amp, but no one approaches my rig.

[quote name='icastle' post='1024126' date='Nov 14 2010, 06:23 PM']Has anyone tried one of these? [url="http://www.auralex.com/sound_isolation_gramma/sound_isolation_gramma.asp"]http://www.auralex.com/sound_isolation_gra...tion_gramma.asp[/url][/quote]There are circumstances where they're helpful, as in flimsy stages. The main factor they're intended to address is transmission of cabinet vibrations into the floor, but unless your cab is really poorly constructed the vast majority of floor excitation is caused by acoustical transmission, not mechanical, so a pad won't stop the floor from vibrating. It will isolate the cab from those vibrations, though.

My Super Fly would get quite hot if not fan cooled, so I added one. I assume that was a lesson learned by Ashdown as well. I'd have the thermistor bypassed to run it constantly, especially as the thermistor seems non-functional anyway.

[quote name='Jean-Luc Pickguard' post='1022493' date='Nov 13 2010, 09:54 AM']No one puts a pint on top of my rig no matter how level it is[/quote] Ah, you prefer a fifth then? Perhaps a bit OT, but if you can't put a pint or whatever atop your rig without it doing St. Vitus dance it indicates insufficient bracing of the cab. Aside from the issues of where to put your drink any energy expended in vibrating cabinet walls is energy not making it's way to the audience as sound. The two corners most often cut by cab manufacturers are bracing and damping, as you can't see if they're properly in the cab without opening it up. Tilt backs are a good idea in a combo, as combos should be tilted back so you can hear the mids. The reason for a dearth of them is the same reason why most acoustically valid concepts see limited usage, and that would be how it looks.