Bill Fitzmaurice

[quote name='LukeFRC' timestamp='1391016560' post='2352320'] I was thinking of building a jack or two too, I didn't think the 15 was that much better than the 12 and would have probably tried to build the lite version. What a lot of users, and Bill himself, said is that they do need Eq to work well - and my preamp doesn't really have enough bands to do that. [/quote]A five band EQ is sufficient, maybe four if one is parametric. But two or three isn't going to do it for most. As for the lows, they're no less than any 1x15, and more than most. But the mids are so much more prominent that it may seem to have less low end.

[quote name='discreet' timestamp='1390810749' post='2349643'] What it actually is that's making that difference for me, I admit I don't know. [/quote]The power supply. The main deficiency of most Class D amps is that they lack sufficient capacitive storage capacity. Manufacturers in their zeal to make the amp as small as possible don't put in enough capacitors to do the job. If you look under the hood of a really well made Class D you'll find half the chassis filled with storage capacitors.

[quote name='discreet' timestamp='1390781290' post='2349552'] That's just it - no huge transformers - no oomph. Physics! [/quote]Class D is about the power amp, not the power supply. No one who owns one of these complains about lack of oomph. https://www.djdeals.co.uk/prod-details.asp?AID=3067

[quote name='DiMarco' timestamp='1390688930' post='2348409'] I tried the brightbox both horizontal and vertical. There is no difference in the sound whatsoever (even when walking up n down the room) by putting it up straight so it is going to remain horizontal. [/quote]That's not where you'd notice a difference, it's side to side. The reason why can be found here: [url="http://www.gtaust.com/filter/05/07.shtml"]http://www.gtaust.co...ter/05/07.shtml[/url]

There are two issues here. One is Class D amps. There is nothing about Class D that's inherently any better or worse than any other class. How well or how poorly the manufacturer makes it is the question, and where that's concerned you can make a really good or a really bad amp of any class. The worst amp I ever had was all valve A/B. The other issue is DSP. You're seeing a lot of Class D amps using it, because that's what accounts for the majority of new amp designs. If DSP had been available when SET ruled the roost they'd have been in those as well. Here also implementation is the issue. Some are very good, some not so much. You can pretty much tell which came out of the minds of engineers who also happen to be bassplayers, and which from those who'd be more at home doing video games.

[quote name='xgsjx' timestamp='1390643295' post='2347789'] There's some on here that say Orange bass cabs are just guitar cabs in disguise. [/quote]Not really, as they do use bass drivers. But the bass drivers they use, Eminence Beta 10 and Kappa 15 for instance, are hardly state of the art, and are way out of line with the price paid for the cabs. As to the OP question, it will take at least two guitar cabs to deliver the same midbass output as one bass cab, and you lose the bottom octave entirely.

[quote name='mcnach' timestamp='1390398493' post='2344917'] I wonder what the collective wisdom and experience here says. [/quote]If you like what you have but need it louder for big gigs add another, it will sound even better. If you don't like what you have try other cabs and when you find one that's better get one, or two, and sell/trade what you have now. Asking others opinions of what might work best will get you almost as many different opinions as you do answers, none of them valid, as no one can tell you what you like. Only you can do that.

[quote name='xgsjx' timestamp='1390258248' post='2343373'] If it's an actual Neutric Speakon, if it says Combo on it, then you can pop a 1/4 jack in it. [/quote]You can tell by the color. Speakon 1/4" combination jacks are green.

Consider the last thing that lies between your ax and you ears: it's your speakers. Everything that preceeds them all the way back to the strings will only sound as good, or as bad, as they will allow.

[quote name='Salt on your Bass?' timestamp='1389891918' post='2339226'] I'm running an ashdown abm 500 and throw a lot of lows at it with my effects set up - lots of30 hz sub etc. is there any danger that this will cause damage to the amp (pre or power stages?)[/quote]Maybe. Few speakers are capable of doing anything that low, so most of what your asking the amp to do the speakers won't allow, and you won't hear. But the heat created by having the amp produce those low frequencies will be there, and heat is the enemy of every component in your amp.

Chances are those are EVM10s. They aren't much of a bass driver. For similar results you can use Eminence Kappa Pro 10s. They're not the best bass driver either, but still adequate to go along with what's probably an EVM15B in the other cab.

[quote name='bassman7755' timestamp='1389788586' post='2337854'] Isn't a single larger cab inherently more efficient at lower frequencies ?. [/quote]No. Low frequency sensitivity is proportional to the cabinet volume per driver, not the cabinet volume.

[quote name='essexbasscat' timestamp='1389738057' post='2337469'] Is there a difference in sound ? [/quote]Not if the configuration is identical save for the panels separating the two drivers.

You use one amp for lows, one for highs, with an electonic crossover splitting the signal before it goes to the amps. Some electric bass heads have an electonic crossover and dual amps. It's used all the time with PA. For that matter it's used in home hi-fi/HT; an x.1 AVR and powered sub is a bi-amped system. It's seldom used with electric bass, other than to sometimes separately power woofers and tweeters. PA uses it to separately power subs and mains, but electric bass cabs are all full range, so there's no point in, for instance, bi-amping a 1x18/4x10, because both cabs share roughly 80% of the same frequency coverage.

[quote name='eddies left thumb' timestamp='1389390108' post='2333881'] I cant figure out what sort of fault it could be it is. [/quote]The previous owner swapping out drivers would explain it.

[quote name='DiMarco' timestamp='1389545831' post='2335321'] In the nineties I often visited a great coverband with lads from Liverpool, their bassplayer was using a Karlson cab with 15" speaker with an old Ibanez Musician bass. His tone was stellar. [/quote]That's not out of the question, Stanley would not have used them if they sounded bad. Compared to the average bass cabs of the 60s and 70s they were pretty good. But I wouldn't play through any of them today. And neither does Stanley.

Freddy is well known as a fan of the Karlson, the only one that I'm aware of. You have to be a real fanatic to do daily searches of the word 'karlson', then join a forum for the sole purpose of championing your cause. Not that I have a problem with that, everyone has to have something to believe in. I believe I'll have another drink.

[quote name='Subthumper' timestamp='1389392742' post='2333912'] Thanks Bill for your input. I was under the impression that it was it bit more mathematical than seat of the pants. I shall pursue another avenue. Shame though cos it looks wicked. [/quote]If you investigate John Karlsons background and look at the claims he made for these it becomes apparent that he really had no clue. Dr. Floyd Toole of Harman said, "The 'Karlson' ... could best be described as an 'acoustic meat grinder', ...guaranteed to make mincemeat from any drivers put into it!"

[quote name='Subthumper' timestamp='1389374711' post='2333585'] So does this mean they're no good for bass guitar? From what I've read they were used for hifi, pa and studio monitors and apparently were pretty efficient. It's just that I'm on the charge to build a cab and wanted something weird and different to conflict all those boring square boxes that all.look alike and sound average. [/quote]You had it right in your first post: [i]If they were as good as claimed how come you never hear of them? [/i] The design dates to 1954, twenty odd years before the use of T/S specs to design speakers became widespread. It was, as all cabs were in 1954, an empirical 'seat of the pants' design. It faded into obscurity for good reason.

[quote name='Subthumper' timestamp='1389350613' post='2333079'] If they were as good as claimed how come you never hear of them? [/quote]That answers your question right there. BTW, the inventor himself didn't know what they were. He called them horns, they were not. They're 6th order series tuned bandpass enclosures: http://www.the12volt.com/caraudio/boxes6.asp Thye differ from the picture shown in the link only by the shape of the port on the cabinet front.

[quote name='DiMarco' timestamp='1389286493' post='2332407'] Ow and comb filtering? The 2x15 doesn't go above 4kHz and the brightbox not under 4kHz. [/quote]For there to be no comb filtering the drivers in the bright box would have to be no more than one wavelength apart center to center. At 4kHz that's 3.4 inches. At 6kHz that's 2.26 inches. Also, that box should be run down to where the fifteens start to beam, which would be around 1.2kHz. To run them only above 4khz wastes their capacity as midrange drivers. But that only applies when vertical. Those drivers will act as one below their 1 wavelength CTC frequency. Assuming them six inches apart CTC that means below about 2260Hz. Placed horizontally they will beam below that frequency just as if they were a single 20 inch driver, so they'd have narrower dispersion than the fifteens. [quote]Trace Elliot put rubber feet under it so they reckoned this position is okay too...[/quote]If they reckoned anything it's that the average user would have no idea that drivers should be placed vertically, nor why, and that they'd best show them that way in their advertising, lest people not buy them because they 'didn't look right'. Never forget that what sells most speakers isn't technology, it's looks.

[quote name='DiMarco' timestamp='1389251647' post='2331822'] Exterminate! [/quote]Place it upright. Laid down as you have it you're creating massive comb filtering in the highs, while in the mids the dispersion angle is less than 1/4 what it will be when upright.

[quote name='Lozz196' timestamp='1389210917' post='2331492'] Must admit, I have the CMD121P combo and NY121 and although when playing on my own I notice the tweeter a bit, I don`t when the band is going. I`ve also not noticed much difference with the tweeter off on the NY121. I do use dead roundwound strings though - maybe it`s only really noticeable with newer strings? [/quote]One of the reasons why tweeters and electric bass are not a match made in heaven is that most tweeters don't do much below 4kHz, while added zing is really needed above 2.5kHz. That's with rounds; with flats there's no need for any assistance, even at 2.5kHz. But tweeters capable of going to 2.5kHz, and the crossovers that are necessary to go with them, are more expensive, so they're seldom employed. I wouldn't use tweeters with flats, and when shopping for a cab for rounds I'd be sure that the 2.5kHz range is covered by the tweeter or a midrange driver.

[quote name='Ghost_Bass' timestamp='1389197267' post='2331214'] It can? How? Will the x-over present a diferent impedance to the amp?[/quote]It can make the crossover appear as a dead short. Read this: http://www.bcae1.com/xoorder.htm [quote]MB has the NY121 cab that is made to be the best extention cab for the CMD, from looking at it (never owned or opened one) they seem to have a very similar tweeter, if not the exact same one. They are fitted with an L-Pad so i guess it's possible to fit one on the CMD, isn't it? [/quote]An Lpad will only work as it should with a resistive load, piezos are a capacitive load. To use a piezo with either an LPad or a crossover additional components are required.

[quote name='Ghost_Bass' timestamp='1389181448' post='2330911'] Disconecting the tweeter won't harm the amp, [/quote]Disconnecting a tweeter can harm an amp, if the tweeter uses a crossover. Most piezo tweeters don't, but one must be sure of that before cutting wires. [quote]I would start with just the L-Pad first, who knows if lowering the existing tweeter a little won't be suficient[/quote]LPads don't work with most piezos. [quote]I would be wary of replacing a piezo tweeter with a dynamic one without also installing a new crossover, as piezo tweeters have very high impedance and the existing crossover is unlikely to be suitable. [/quote]True. This is not a job that should be attempted by someone not totally familiar with what they're doing.