Bill Fitzmaurice

[quote name='leosep' timestamp='1391781745' post='2361213'] Thanks bill, yes i know drivers and cabs must be matched, using speaker modeling software, i have WinISD. Just wanted to know if these spekers that i already have could do the job, at least for a practice cab. I think i need to buy new ones then. I dont have the cabs done yet. [/quote]If you already have them you've got nothing to lose, and it gives you the opportunity to experiment without making a huge investment.

This is one of those "if you have to ask" scenarios. Drivers and cabs must be matched, using speaker modeling software, like WinISD Alpha Pro, which will accurately predict the low frequency response and maximum output, while results above 200Hz can be seen on the driver data sheet SPL charts. If you had the necessary skills to design your own cab, or to driver swap with an existing cab, you wouldn't be asking this question, and acquiring these skills literally takes years. If you're just learning start with tested designs using the drivers recommended for them for the first few builds; when you really start to understand how speakers work then you can start experimenting on your own. As to those drivers, the first and last I'd avoid because you don't get the quality you need at those prices. The second looks OK, but the mids are weak, so it would best be used in a three way design. It's more of a PA driver than electric bass.

[quote name='Roland Rock' timestamp='1391204312' post='2354662'] Would playing them too cold mean lack of optimum performance, or actual risk of damage? [/quote]I've had raw drivers that I left in my workshop overnight at 40F measure nearly an octave above spec. If you were to play though them in that state and try to get them sounding normal you might damage them. It's like a car, you don't want to start it cold and go to cruising speed before the oil has come up to temp. Not that you know what cold is, a Scotsman might.

[quote name='Marvin' timestamp='1391180164' post='2354244'] I'd like to keep the character of the cab, it's got a lovely amount of of low end. [/quote]You'd have to match the T/S specs and response of the drivers, and Ampeg won't give you that information, nor will Eminence as it's a proprietary OEM driver. I can tell you that the OEM drivers weigh only 6.7 pounds each, so you'd save very little, if any, weight with neos.

[quote name='NancyJohnson' timestamp='1391188361' post='2354424'] I suppose I have concerns over speaker degradation and bring the cabinets from a cold environment into a warm/moistish one. [/quote]That concern is valid. Cold speakers don't work to spec, and it takes a long time for them to warm, as the insulation inside them works like a cooler. So long as they're stored above freezing you're OK, but I wouldn't store them where it goes below freezing unless they'll have a few hours to warm up before using them.

[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.