alexclaber

[quote name='Mr. Foxen' post='312292' date='Oct 22 2008, 04:47 PM']Rocked it as is last night in practice, sounded great. Paired it with a Marshall JCM600 into a 4x10 for some top (make up for single guitarist). Filled the place with low end.[/quote] Excellent! If it ain't broke... Alex

[quote name='EBS_freak' post='311779' date='Oct 22 2008, 08:48 AM']Hmm. Thought as much... so why aren't there more powerful single power amps hence negating the need to bridge two? Or are there? Or is the bridging of two power amps a cost saving mechanism?[/quote] I gather many of the new lightweight heads are using generic power amp modules rather than developing their own, which makes a lot of sense as you don't otherwise get the economies of scale with the small market that is the bass guitar world. Alex

[quote name='EBS_freak' post='310888' date='Oct 20 2008, 11:20 PM']Is there a 2 ohm class D out? I thought that they run too hot at that load... or perhaps am I completely wrong??[/quote] The reason that quite a few lightweight Class D bass amps can't run down to 2 ohms is that their output stage consists of bridging two lower power amplifiers (both rated for 2 ohms) thus giving you a 4 ohm limit. Class D has no problem at all with 2 ohm operation if it's designed for it and is far less likely to have overheating problems than Class AB due to its higher efficiency. Alex

[quote name='dave_bass5' post='311398' date='Oct 21 2008, 04:19 PM']Am i right in thinking i can just put a short strip under each end of the cab (front to back).[/quote] Yes. Alex

If the speaker is knackered and you definitely want an 18" then I'd get the cheapest possible 18" you can find. You don't need the Xmax or thermal power handling of a more expensive speaker, nor do you want the lower Qts of a speaker with larger magnet. This one looks ok - higher Qts, low-ish Xmax, as full-range as 18"s get: [url="http://www.bluearan.co.uk/index.php?id=BMASM118N&product=Beyma_SM118N&browsemode=category"]http://www.bluearan.co.uk/index.php?id=BMA...semode=category[/url] Not cheap but that's 18"s for you. Alternatively get the original speaker reconed if you can, that'll give you the true warts and all sound. Alex

[quote name='bilbo230763' post='310526' date='Oct 20 2008, 03:44 PM']But seriously, I dealt with it another way. I got everyone to turn down. Radical, eh?[/quote] If you work with any drummers then you are endangering your ears if you do not wear earplugs. Even with brushes the peak SPL from a snare is easily enough to cause damage. Alex

Obviously the goal is not accurate deep bass reproduction, which is why a driver designed for a large extended bass shelf ported cab or a full-length bass horn is not a good idea. My concern with simply fitting a high sensitivity 18" is that the lower Qts will badly choke off bass response. Combine that with the shortness of the horn and it could sound like it has no bottom whatsoever. A less tightly damped driver of lower sensitivity could actually have more sensitivity where you need it and thus be louder. And the plus of that is the latter type of driver is cheaper to make due to the smaller magnet. Alex

[quote name='Mr. Foxen' post='310332' date='Oct 20 2008, 12:12 PM']So you are saying I should take my vintage cab, and then design and build and entirely new, different shaped cab, with a different sized driver?[/quote] No, I am saying you should stick a piece of ply over the existing hole with a new hole cut in it to fit a 3015LF and then leave it be. I am also saying you shouldn't put a modern 18" into the cab unless you have checked it will work well. Alternatively I would try to find out what the rough specs were on the original driver and then find something similar. Putting an expensive pro-audio driver into an esoteric old cab design is like putting a modern racing engine into an old VW bus - not a good match! Are you sure it's the driver farting out first and not the amp running out of power? Alex

[quote name='Mr. Foxen' post='310294' date='Oct 20 2008, 11:23 AM']What variables would you have to measure to model the cab? Its all folded horn shaped inside, so don't even know how you'd go about calculating volume.[/quote] You need to calculate back enclosure volume, horn length, throat area, mouth area and flare rate. It's nothing like modelling a direct radiator cab where all you need is net volume and tuning frequency (if ported). The reason I suggested the 3015LF is I know it's proven in other horn cabs and it has just as much Vd as the linked 18" and higher Fs and Qts which should equal louder and bigger bottom where it matters. So ignoring price it's still better. I haven't paid much attention to 18" woofers suitable for old horn cabs because they aren't terribly relevant to 99.99% of bass players - if you're going to use a horn you're better off with a smaller high excursion driver pushing a smaller throat and a longer path, hence the obsolence of the Acoustic 360 et al. Alex

[quote name='joegarcia' post='310249' date='Oct 20 2008, 10:09 AM']What do peeps reckon to this speaker: [url="http://www.bluearan.co.uk/index.php?id=BAC18PS76&product=B!amp!C_18PS76_18!dquote!_600W_Low_Frequency_Driver_8Ohm&browsemode=manufacturer"]http://www.bluearan.co.uk/index.php?id=BAC...de=manufacturer[/url][/quote] Qts is rather low. I suspect you'd get much better results from a 3015LF and as the mounting holes are unlikely to be compatible you're going to have some woodwork to do with most 18"s so why not fit a better and cheaper 15"? If I was replacing the woofer in a horn I'd model the cab in horn resp. to see what fits best. Alex

[quote name='mr.sibs' post='309937' date='Oct 19 2008, 05:37 PM']that bk would be just the thing with a lower rating, not sure about those waiting times though, but thanks[/quote] The BK module is 600W into 2 ohms, much less into 8 ohms (as your Omni 10.5 presumably is). Alex

[quote name='charic' post='308770' date='Oct 17 2008, 05:17 PM'] that mic must be wrecked by now then[/quote] The C1000 makes a pretty good (and robust) live snare mic, as do other small diaphragm condensers designed for similar use. I wouldn't want to put any studio type condensers near a drummer's sticks! Alex

[quote name='Thunderhead' post='308568' date='Oct 17 2008, 01:17 PM']Good cabinet design can reduce the weight too, but I always find that the really heavy ones somehow sound more solid and punchy. It's a difficult compromise, for me... I've yet to hear anything that I really like the sound of that I also don't hate the effort required to move. It would be nice if someone could crack it.[/quote] From what I can see of most lighter weight cabinets (and many heavy ones too) is that they're insufficiently braced. My old Acme cabs were 3/4" ply with pre-stressed cross-braces - very rigid indeed. To get similar rigidity with my 3/8" ply cabs I'm running ribs along all the panels and then using tensioned cross-braces. The downside is the extra time it takes to build them and they're not quite as light as an unbraced lightweight ply cab but they're a hell of a lot better sounding! Alex

[quote name='ped' post='307466' date='Oct 15 2008, 11:01 PM']The pickups look like Lane Poors![/quote] Yes, they do. If they are then they're probably worth more than you paid for the bass! Alex

[quote name='~tl' post='307906' date='Oct 16 2008, 02:32 PM']It depends on the power draw of your amp. This is usually written on the back. Divide that by 230 (mains voltage) and you will have the current your amp requires. You should use the nearest size fuse bigger than that. Basically, the common size fuses relate to the following maximum power draws: 13A = 2990W. 5A = 1150W. 3A = 690W.[/quote] Note that many amps will have much higher inrush current when switched on, as the capacitor bank goes from empty to full in very little time, so a standard 5A fuse could be blown by a typical bass head. To avoid this you should use a slow-blow 5A fuse which allows much higher instaneous peak current. Any amplifier manual should cover these details. I've always know that I should use RCDs at gigs but have been too lazy to use them. Having read this thread I'll be sure to use one in future. I am left wondering whether an RCD on the bass amp would have prevented this - was the current coming from the bass amp and through the bass or from the PA and through the mic? Probably the latter methinks... Alex

[quote name='stingrayfan' post='308172' date='Oct 16 2008, 09:20 PM']Killers - Hot Fuss (esp. Jenny Was A Friend Of Mine and Somebody Told Me)[/quote] Absolutely. He is so present, both on the album and when they play live. Amazing BIG tone. Alex

[quote name='ARGH' post='308152' date='Oct 16 2008, 09:02 PM']good wood is good yes? But its good on the eyes,if we were looking for ultimate wood,we would probably found the 'right' combo by now,as some luthiers,think they have,but I dont hear that,and I think a lot of it is influence of fashion (my point on tops earlier) and aesthetics (saying that Dr Daves Rotten topped Shuker looks,sounds and feels devine)..the thruneck/Bolt on argument is testament to this..Ernie Ball's militantly TIGHT as f*** bolt on neck pocket (that in some cases a slip of paper cant fit through) Vs ..I think..Sadowsky's or maybe Mike Lull's opinion of the opposite[/quote] I agree that good wood is good. That much of the fuss about woods is driven by aesthetics and fashion. That bolt-on v neck thru matters more to access than tone much of the time. I do not agree that we could find the ultimate wood because different players want different sounds. I also agree that everyone making a fuss about tonewoods would be better served by daring to try longer scale lengths - a 36" scale is a revelation. But that doesn't make tonewoods unimportant. I don't know how much fingerboard wood matters. I do know that neck stiffness has a huge effect upon the note envelope. Body wood self-damping, mass and resonance also has a huge effect on which overtones are absorbed and how they are either lost or returned to the string. There is one time that wood really really makes next to no difference - when its composing the body wings of a thru-neck graphite bass with a heavy bridge and the wings are solid, not chambered. Very little energy going into those wings and then returning to the strings. I know you like to make sweeping statements because it's both easier and suits your generally ARGH demeanour but it's not terribly useful when they're only slightly accurate! When is good wood not good wood? When it looks nice but the bass sounds crap whatever electronics you put in it, whatever strings you put on it and however you play it. And that too is when wood really really matters! Alex

If I was DIYing and not intending to get deeply involved in the design process I'd focus on the Bill Fitzmaurice plans. I ended up designing my own cabs after considering a BFM DIY build (I bought all the plans) but I have spent literally thousands of hours over the past few years on trying to design the perfect cab for me... Alex

I'm unconvinced by digital modelling, particularly when playing and there is that response loop between hands, instrument, amp and ears. I haven't done any ABY testing of Class D vs Class AB amps myself but I did replace a Class AB Mackie power amp with a Class H SMPS QSC and the latter wins on all fronts (bar price). However, if you prefer the sound of a Class AB amp then there's little reason to go Class D etc to save weight - it's not hard to make a conventional bass head weigh under 25lbs which isn't a lot to carry. It's the cabs that make the difference when you're looking at going light. Alex

[quote name='hookys6stringbass' post='308119' date='Oct 16 2008, 08:13 PM']Ha!! He's certainly not clueless.... I understand what you're saying Alex and you make alot of sense, but for me I have to dispense with the Mr Spock logic sometimes and try things out as the 'what' if factor will drive me nuts. Yes the amp sounds 'superb' but'what if' I can get it to sound even better or discover a warmth or what ever I hadn't heard in the amp before.[/quote] Well in that case, download WinISD Pro, calculate your cab net volume and current port tuning frequency, and start modelling drivers. See if you can get the T/S parameters for the current speaker - if you contact the speaker maker (not Ashdown) with the serial number you may be able to get them. He may not be clueless about many things bass related but anyone making a sweeping statement as he did is acting in a clueless manner at that point in time. The Gamma 15 and Truvox 15/30 aren't great speakers. The Xmax on the former is poor and on the latter terrible. Probably no worse than the original speaker but unlikely to be a significant amount better. The Truvox is a great example of why power handling ratings aren't of much use for bass guitar - it's thermally rated at 400W but with Xmax=2mm it's excursion limited to well under 100W. Alex

[quote name='hookys6stringbass' post='308049' date='Oct 16 2008, 05:54 PM']I know what you mean, but this guy I was talking to was quite passionate about what he was talking about and it really has got me thinking 'what if'. Im hoping to pick some drivers up off ebay. So far i've been recommended .... Celestion 15/30 tru vox Eminence Gamma[/quote] Unfortunately he sounds like he doesn't have a clue what he's talking about. Passion is all very well but you have to know how to apply it. If you want to change how your cab sounds you need to analyse what you want to change about the sound and then go through a logical process of ascertaining how to achieve that change. But if your cab really does sound superb then I can't think what you could want to change. The best standalone 15" speaker for the money IMO (and I have done a LOT of searching) is the Eminence Kappalite 3015. But you do pay for that quality. And you may not like how clear and bright the top-end is and how strong the midrange is. Alex

I'd love to see a blind ABY test to see if you really can always identify the Class D amps from Class AB ones. Can you hear a difference between mains frequency transformers and SMPS's as well? Alex

[quote name='Merton' post='307848' date='Oct 16 2008, 01:21 PM']If you like it why change it? Don't let GAS get the better of you!![/quote] Exactly! Changing speakers on a whim when you already think it sounds superb is not a wise idea. Alex

Not terribly recent but just post 2000, D'Angelo - Voodoo is essential listening for all bass players. Like nothing you have ever heard before. Pino Palladino, Rafael Saadiq and Charlie Hunter laying down the bottom with ?uestlove on drums. Alex P.S. The recently released EP by The Reluctant also features some righteous bass work (see sig!)

[quote name='Mr. Foxen' post='307725' date='Oct 16 2008, 11:01 AM']Would that be the same sort of difference felt with through/back stringing and reverse headstocks?[/quote] Yes. Break-angle and nut/saddle friction has a huge effect too. With roller saddles through body stringing could decrease apparent string tightness because the extra length of string can contribute stretch, whilst with sharper saddles through body stringing could increase apparent string tightness because the sharper break angle decreases the involvement of the string between saddle and anchor. Alex