Bill Fitzmaurice

[quote name='richrips' post='728174' date='Jan 28 2010, 05:13 PM']This is my rig, 2 x BFM jack 12's [url="http://basschat.co.uk/index.php?showtopic=60932&hl="]http://basschat.co.uk/index.php?showtopic=60932&hl=[/url] and an ovation magnum or stingray[/quote] My rig is one J112, loaded with a 2512, so yours is better than mine. You should be able to do stadiums with those cabs, so something in the amp setup is out of whack. Be very sure the cabs aren't out of polarity.

Make sure the EQ isn't the culprit. I get enough output from a 1x12 on one channel of my Superfly, but only using my own EQ presets. The factory presets were all set to less than unity.

[quote name='bumnote' post='726635' date='Jan 27 2010, 01:01 PM']are you saying the orange 2x12 is only as loud as a single 10? can you explain a bit more[/quote] That's a bit off, an isobaric 2x12 will have the same output as a standard 1x12. The second driver allows the cab to be made smaller with no sacrifice in response, but that bit about there being no such thing as a free lunch reigns true to form, so what is sacrificed is output. The same two twelves in a larger cab would go louder.

[quote name='geoffbyrne' post='720101' date='Jan 21 2010, 08:40 AM']I think BFM said recently, that you shouldn't be able to see the back of the speaker if you look through the port(?)!! G.[/quote]Correct. If you can see the cone then midrange waves can exit the port, which you don't want. Aside from that caveat the port can go anywhere.

[quote name='ViVi' post='719671' date='Jan 20 2010, 06:24 PM']Assuming venting the box, will there be any significant difference betwen the Kappalite and BL15-400X?[/quote]The BL-15 400X has specs close enough to use it sealed, but a 3015 vented will have a lot more low frequency capability than the BL-15 400X either sealed or vented. 40 to 45 Hz tuning will give the best result.

[quote name='Mr. Foxen' post='719431' date='Jan 20 2010, 01:50 PM']Is there a spreadsheet or a way of extracting all the T/S characteristic from WinISD into a spreadsheet, so you can sort by the characteristics you are looking for? Cause once you know stuff like Bill says, you still have to look at every driver to spot them.[/quote] There's none I'm aware of. But if you know how to design speakers you also know how to check driver data sheets and wean out unsuitable drivers literally at a glance.

[quote name='ViVi' post='719226' date='Jan 20 2010, 11:37 AM']Hi all, I am reconstructing my “old vintage cabinet” (nice piece of furniture) and would like to replace the driver. I went through this forum and the best option seems to be Eminence KAPPALITE 3015 or Celestion BL15-300X/BL15-400X. The cabinet is sealed, approx 160 litres and the intention is to use it standalone. I run it through WinISD and it seems that the Kappalite has more midrange response. Will it lead to more clarity? The Celestion BL15-300X seems to be half price of the Kappalite. Will the difference in sound be important or negligible? Many thanks for opinions ViVi[/quote] Neither are well suited to sealed alignments, which typically require a driver Qts higher than .50 and EBP less than 75. WinISD does not predict midrange, it's only accurate up to roughly 200 Hz.

[quote name='goingdownslow' post='717917' date='Jan 19 2010, 09:59 AM']Could this speaker cable be referred to as being coaxial? [url="http://www.canford.co.uk/Products/33-250_CANFORD-HPS-CABLE"]http://www.canford.co.uk/Products/33-250_CANFORD-HPS-CABLE[/url][/quote]It is speaker cable, but IMO not a good choice. Signal loss in speaker cable is through capacitance, and the capacitance of a coax cable is much higher than side by side conductors. The reason for using coax cable is that the shield minimizes noise pickup in instrument cables, speaker cables are immune to this sort of noise pickup.

[quote name='Sumbabba' post='717586' date='Jan 19 2010, 05:58 AM']Hi! Anyone know where in London I can buy a coaxial speaker cable for my lovely new Warwick Hellborg rig?[/quote] Speaker cables aren't coaxial, instrument cables are.

[quote name='Mr. Foxen' post='714033' date='Jan 15 2010, 12:14 PM']What about them? There are factors other than driver diameter at play. They don't sound good because there are 10s and 12s,, they sound good because they are designed taking all the factors into account (or at least getting them right inadvertently).[/quote] [quote]I asked TC about their cab matching, and they said all their artists bar a few chose the 210/212 because it just works. They designed them to work how they do[/quote] I seriously doubt that. They look to be reasonably well designed and constructed, but no more so than cabs from a few dozen other companies building bass reflex cabs loaded with Eminence drivers. There is one fact of audio physics that's never mentioned by any manufacturer: virtually any two cabs together will sound better than either alone. So while the TC 210s and 212s might sound OK together so will most of the 210s and 212s from any other manufacturer. The pertinent question is whether paired TC 210s or 212s would sound better than one of each. That one can only determine by trying all three permutations side by side. On a side topic the TC 2x cabs do place the drivers vertically, and that is infinitely better than side by side, so that much they got right. But they have a traditional 4x10 in the line up as well, so they're not above sacrificing engineering concerns to the gods of marketing.

[quote name='Al Heeley' post='713969' date='Jan 15 2010, 11:25 AM']If thats the case then why do all the major companies sell same impedance 410's, 210's and 115's, designed to be used in pairs?[/quote]Your question is its own answer. Cab companies build and promote what they think will sell, and the vast majority of players buy their cabs based not upon the engineering within but rather on how they look and who uses them. Mixing drivers to cover the same bandwidth is not good engineering, but it is successful marketing. If you must succumb to the lures of that marketing a 1x15 and 2x10 are a reasonably good match. A 1x15 and 4x10 isn't. [quote]Some cabs are made so that they can be mixed, with time aligned, phase coherant and excursion matched cabs, but probably not many.[/quote]I'm not aware of any. If any of the usual sources possessed the technical know-how to do that you can rest assured that they wouldn't keep it a secret. AccuGroove tries to make it seem that way in their ad copy, but their level of technical incompetence was tellingly revealed in the AccuSwitch debacle. The only significant engineering that I'm aware of where mixed cabs is concerned lies in making the footprints the same for stacking. More than a few 1x15 and 4x10 cabs share not only the same footprint but the exact same cabinet save the number of holes in the baffle. That should set off alarm bells, but curiously it doesn't. The stacking of the two looks very pretty, so it sells.

[quote name='Phaedrus' post='711114' date='Jan 13 2010, 06:43 AM']I can't escape the concern that stuff will shake loose inside - does this happen?[/quote] Only if it gets away from you on a steep hill.

[quote name='BottomEndian' post='710130' date='Jan 12 2010, 11:00 AM']Oh yeah. Of course. I'm even more confused about the noise now then. :wacko: EDIT: No, wait. It's still got a switching power supply, so is it possible that the power supply kind of "runs down" its clock speed as it powers down, thus creating a falling-frequency noise?[/quote]I've heard that with many amps, it's just an artifact of the supply caps discharging.

[quote name='Beedster' post='708480' date='Jan 11 2010, 03:07 AM']I received a brief reply...confirming that the noise is usual on this model.[/quote]Odd that it doesn't say so in their ad copy.

[quote name='AlanP2008' post='707552' date='Jan 10 2010, 07:15 AM']Re Xmax/Xlim: My understanding is that if you exceed Xmax, distortion will exceed some arbitrary value that the manufacturer uses to establish Xmax, whereas exceeding Xlim is likely to result in damage.[/quote]There's nothing arbitrary about xmax, it's when distortion reaches 10%. Some manufacturers still use the old coil depth versus plate thickness method, and that is arbitrary and obsolete. Xmax tells you the maximum safe power level that may be applied, and it's what you consider if you have a limiter that allows restricting power amp output, though that's more of a PA scenario. Exceed xlim and the driver is damaged, irreparably so, so it's not something you want to even vaguely flirt with. [quote]I had a trace 2x10 with horn,uprated to 400w neo style,yes more responsive but didnt seem to handle the full range,[/quote]All that indicates is that you used the wrong ones. You can't just drop any driver into a cab willy nilly and expect a good result. A very fair amount of research is necessary, as this thread reveals.

[quote name='AlanP2008' post='707220' date='Jan 9 2010, 06:14 PM']The best thing I found, was in trying a single Eminence Delta 12 LFA - a single 12", and it seems much better than a Deltalite 2512... It's Resonance is pretty low at 51Hz, and also being a single speaker in the cab gives an excellent bass response, but mainly, it has a massive Xlim at 13.5mm, which allows a lot of power to be used even with bottom strings. Ok, Xmax isn't so high, but it is good at 4.8mm. I know there is likely to be increased distortion if this is exceeded, but at least it won't be trashing the voicecoil...[/quote]Try the 3012HO. Xlim is moot, xmax is everything. The D12LF was state of the art ten years ago, rendered obsolete by the 3012HO, which is also a contender but really needs to be used with a six ought five midrange.

[quote name='Beedster' post='705390' date='Jan 8 2010, 07:51 AM']according to PJB, without the hissing/whistling noise as the result of musing a different class amplifier C[/quote]I hope PJB knows the difference between amplifier classes, and that noise is not an inherent quality of Class D. Noise can be a problem with switching power supplies, and switching supplies are often employed with Class D amps, but having the one doesn't always mean having the other. In any event, with the recent flooding of the market with micro amps one doesn't have to look to only one source. I'd be looking at alternatives other than just a more expensive one from the same source.

[quote name='Beedster' post='704167' date='Jan 7 2010, 08:59 AM'], he's now come back to me reporting a phone conversation with Phil Jones himself, in which it was determined that the noise is normal for the Flightcase and for Class D amplifiers generally (which is apparently why I don't get similar noise problems with other, larger, amps). Am I being fed some BS here, or should I just accept the noise as perhaps the only limitation of an otherwise pretty good piece of kit? Thanks Chris[/quote] BS. It's probably clock noise from the power supply, which has nothing to do with Class D, and everything to do with a defect in the amp. I hope it's not normal to the amp, as that would indicate a flaw in the amp design.

[quote name='chris_pokkuri' post='701345' date='Jan 5 2010, 05:36 AM']Hi all, happy new year! I'm planning on getting some effects soon. Just wondering what your opinions are on whether there is a better speaker size and configuration to use with distorted/overdriven bass? Cheers, Chris.[/quote] Effects do nothing below 100 Hz while they can destroy tweeters in a heartbeat. The best way to do it is to run a separate small guitar combo amp above the bass rig and run the effects through it only.

[quote name='pantherairsoft' post='483676' date='May 9 2009, 07:26 AM']WHich seems stupid as Ashdown seem to only make 8Ohm cabs, menaing they make nothing perfect for the Little Giant head... hardly a strong marketing idea![/quote] Get 8 ohm cabs. Each power amp is quite capable of driving an 8 ohm 1x12, 1x15 or 2x10 to full output, and if that's not enough you could use as many as four 8 ohm cabs total. 'Getting all the watts out' with only one cab per channel is a shortsighted view, unless the cabs in question are 4x10s.

[quote name='AlanP2008' post='700532' date='Jan 4 2010, 10:17 AM']2510: Resonance 53Hz, Usable Frequency Range 60Hz-4kHz, Sensitivity 97.3 2512: Resonance 42Hz, Usable Frequency Range 54Hz-3.7kHz, Sensitivity 99.9 2515: Resonance 42Hz, Usable Frequency Range 54Hz-3.7kHz, Sensitivity 99.2 Basslite S2010: Resonance 46Hz, Usable Frequency Range 54Hz-4kHz, Sensitivity 96.2 Thanks again Alan[/quote]These specs in and of themselves reveal almost nothing about how the drivers work when loaded in a cabinet. That can only be determined using all the driver T/S parameters with speaker enclosure modeling software like WinISD Alpha Pro for the region of pistonic function, roughly up to 200 Hz, and the SPL charts from the manufacturer driver data sheets for above 200 Hz. And then there's the matter of being able to interpret the results. BTW, if one only had the above data as predictors the differences between the four drivers listed would be, for all practical purposes, inaudible.

[quote name='AlanP2008' post='700376' date='Jan 4 2010, 07:39 AM']... I've come to the view that, as someone with an electronic engineering background, and in the distant past an audio engineering background, if I were designing a bass cabinet today, I wouldn't even consider 10" drivers -- 12" would be the minimum, for all sorts of reasons (resonant frequency and useful frequency range being just two of them...)[/quote] If you investigate further you'll find the differences between tens, twelves and fifteens in general are slight, while those between specific models of drivers are considerable. You'd also find that the 2x10 is, all things considered, the most versatile configuration when the drivers are vertically aligned (and most are not) while the 4x10 is the most intrinsically flawed. Where tens are concerned my preference lies with the Eminence Basslite S2010 and Deltalite II 2510.

[quote name='umcoo' post='699668' date='Jan 3 2010, 11:38 AM']I'm looking for a flight case for my 135 and castle cases do one for the bassman 100. I measured the 135 and the case and the case seems a really tight fit. Is that how they're supposed to be? Help me spend money folks![/quote] Check for yourself here: [url="http://www.ampwares.com/"]http://www.ampwares.com/[/url]

[quote name='gnasher1993' post='698816' date='Jan 2 2010, 11:37 AM']So what are the likely stats of that cab?[/quote]98dB/1 watt sensitivity is possible, with a -3dB reading at 45 to 50 Hz. But at 20 Hz it's likely only capable of 70dB/1 watt, with a maximum output at 20 Hz of only 80 to 85dB. 80 to 85dB at 20 Hz is inaudible. [quote]I tried one a few weeks ago and it sounded great, definitely at the top of my list to buy. I don't need frequency response that low so it doesn't matter, it's the sound I want.[/quote] No one needs response that low, and no one sells a bass cab capable of it, so it's silly to lie about having that capability. But that's what marketeers do. Truly useful information would be an SPL chart, polar plots and displacement limited power ratings, SOP in the high end PA world where the customer tends to be very knowledgeable about these things. But I guess if you're not paying upwards of two thousand quid per cabinet you're assumed by the manufacturers to be a rube who'll believe whatever they lay out there.

[quote name='gnasher1993' post='698745' date='Jan 2 2010, 09:27 AM']The Hartke Hydrive 1x15" has a great frequency response all the way down to 20 Hz.[/quote]Only in the fantasy world of marketing department schlockmeisters. In the real world the physics of how loudspeakers work render the claims of [i] Frequency Response: 20 Hz to 17 kHz Sensitivity: 98 dB @ 1 W/1 m[/i] totally beyond the realm of possibility. If you could package up all of the bullcrap contained in the Hartke webpage description of the HX 115 you could fertilize a goodly sized farm with it.