Bill Fitzmaurice

[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.

[quote name='pockethammer' timestamp='1388937880' post='2327820'] I see bass direct offering deals one of which is....... A GB shuttle 9.2 + a 4X10 (600w 8ohm) + a 2X10 (300w 8ohm). now...... If you rig all this up your cabs are down to 4 ohms & the amp will be capable of pushing 900w. Assuming that in reality the master on the amp won't be past 12 o'clock is this still a mismatch or is it workable? Cheers, John. [/quote]It's a mismatch. To be matched the 2x10 should have twice the impedance of the 4x10, so each driver receives the same power. That means a 4 ohm 4x10, and an amp capable of handling a 2.7 ohm load. It may be workable, but it's not ideal. The position of the master, BTW, doesn't indicated how much power the amp is producing.

[quote name='LukeFRC' timestamp='1388590752' post='2323736'] I've been asking this question too... but with the 12/6/1, but the F112 has same tweeter (the APT80) as simplexx... I know which one would be cheaper to build! [/quote]I did not make the Simplexx as 3 ways because their intent was to be inexpensive and easy to build. For the same reason I didn't design them around $300+ drivers. Besides, if one wants a 3 way that will leave fEarfuls in the dust there's already the Omni 12 and Omni 15 designs, currently on tour with The Animals.

[quote name='RandomBass' timestamp='1388484581' post='2322424'] That's an unusual or poor design solution. I'd be interested to know what forced the former. [/quote]+1. I can't imagine the need for a 230v and a 240v version, that's way too slight a difference to matter. 220v and 250v, maybe. Voltage fluctuations of at least 10% are to be expected and gear should be designed to operate with that much swing.

[quote name='flyfisher' timestamp='1388433755' post='2321983'] [u]even if[/u] the mains voltage is 207 volts (i.e. -10%) or 253 volts (i.e. +10%) or anywhere between then the actual amplifier circuitry voltage supply will still be operating from the same fixed, lower-voltage voltage it was designed for. [/quote]That's true with the low voltage rails powering the pre-amp, usually at +/-15v, and any DSPs, usually with 5v, as those rails deliver low current, so they can be voltage limited with zener diodes or voltage regulator chips. That's not the case with the high current rails for the power amp, which very seldom have any method of voltage regulation. But amp manufacturers build their amps to withstand fairly large voltage fluctuations, so seldom is it a problem. In the US the nominal voltage is 110, but it ranges anywhere from 100 to 125v, and you never hear of problems so long as it's within that range. [quote]Markbass and MSL Professional who do the Markbass stuff in the UK said it wouldn`t be, and to only get one made for this countries power supply[/quote]Markbass will say that to discourage gray market sales, and MSL doesn't want you buying from Thomann.

Your right, it's daft. You won't have equal power distribution to all the drivers. With six 8 ohm drivers you can wire them as series pairs for three sets at 16 ohms, parallel wire those sets for a 5.3 ohm total, which most amps will have no issue with.

[quote name='Leonard Smalls' timestamp='1387875199' post='2316608'] Fair enough... But looking at the frequency response curves in the link, they are far from flat! [/quote]And how would you classify this? That's an Avatar 4x10, and if you think that looks bad, you should see it at 30 degrees off-axis. Electric bass cabs are anything but flat response. As for PA, the EAW KF850 was a benchmark for 20 years. This is what it looks like with and without processing:

[quote name='Jus Lukin' timestamp='1387889166' post='2316882'] For recording a cranked amp sound at reasonable levels I like the idea of a small, low sensitivity cab for micing up. Would something like the Legend BP102, with 200W handling, Xmax of 10mm, and a sensitivity of 91.82db be a good idea in a sealed 1x10? [/quote]No, because cranked amp sound is mainly a product of a low xmax driver, not low sensitivity. That's why guitar drivers typically run 1mm xmax.

[quote name='LukeFRC' timestamp='1387829130' post='2316282'] cheers for the reply Bill I've only got 4 bands, and not swept. [/quote]In that case you'd want to try the combination before committing to it. I know there's at least a few on your side of the pond.

[quote name='LukeFRC' timestamp='1387825536' post='2316207'] just I'm not sure that my bass amp would be flexible enough to eq in the right places, I guess ideally you use a power amp with inbuilt DSP and just plug a preamp into that... I understand that practically the horn design is better and more efficient etc... but how practically do you make it work? [/quote]If you have at least a 5 band EQ then you have enough control for a horn loaded cab. It might not be for you with less than that. I use a Superfly now, before it I had a Hartke 3500, both have all the adjustability I need. PA is a lot more fussy, that's where a 31 band with auto RTA is almost indespensible. [quote]@OP: Low efficiency and at 56hz quite a high frequency rolloff. I doubt it's any good for metal. [/quote]The sensitivity of the Thunderchild is no lower than most 112s, and of those that claim having more most are lying. A Fridge has a 58Hz f3, so that's not out of whack either. It's not a design that stacks well, you can use two with the upper cab inverted to keep the HF horns adjacent but any more and there will be integration issues. OTOH it's no worse than most other cabs in that respect either.