alexclaber

Just to clarify a couple of things - tee-nuts don't screw into plywood, they bite into it and are held in by the tension of the bolts. Once the bolts are tightened up you effectively have eight clamps gripping each speaker frame very hard. But they are a bastard to deal with - put too much pressure on the screwdriver when undoing them and they pop out, hence Rob's pains! Great once they're done up though. Also, I said to Rob that I'd arrange to have the cab collected on the same day as he received a replacement cab from me - that way he'd have been able to use the cab with the dodgy handles until the replacement arrived, and not have the cost of returning the cab. Unfortunately he insisted that he could the cab shipped back to me for only £25 and that that would be much more convenient for him and he sent it almost immediately whilst I didn't have the replacement cab sorted for quite some time. And the shipping cost him more than expected probably because he'd thrown away the original packaging and his multiple layers of cardboard solution added quite a bit more weight. Obviously the whole issue arose because I screwed up in the first place (again, sorry!) but Rob, I wish you'd been a little less impetuous and not gone trying to fix the problem yourself, I wish you'd kept the original packaging (at least until the end of the one month trial period), and I wish you'd let me collect the cab once a replacement had been shipped to you. That would have made your experience significantly less painful, especially as I realised that the problem was the two screws being far too small before I received the returned cab and thus I could have sent you the correct long fat screws to put in, which would have entirely solved the problem (and you'd have been £50 better off). But with your impatience to sort things out I rather failed to keep control of the fix - again, sorry! Alex

Hi Rob, If I were you, based on what you've said then I wouldn't keep the cab. Send it back, I'll give you a refund for all your costs so all that'll you'll have wasted is your time, and then buy another cab. If you're not going to use the cab for gigging because you think it's fragile then there's no point owning it. I've noted the points about the velcro - on previous cabs I used velcro from top to bottom but that made the grill nigh on impossible to remove, so in future I'll use about twice as much as on your cab. The tweeter doesn't hiss, that's your bass/pedals/amp - tweeters don't create hiss, they just reproduce whatever's in the signal chain - this tweeter is very transparent and goes very high so you will hear all the hiss from your equipment. The tee-nuts/bolts clamp the speakers in very securely but it is an art removing the speaker without causing them to pop out - unfortunately you removed the speaker without telling me so I didn't have a chance to advise you on the best method! There have been no other problems with handles on Barefaced cabs - but this was entirely self-inflicted by me putting the handles on quickly for the Brighton Bass Day demo and forgetting that was a temporary fix. Certainly something that won't happen again! As I said before, I'm sorry it caused such pain. Regarding the apparent lack of lows, either the speakers haven't loosened up yet (how many hours has it been used at high SPL for?) or you're doing something seriously wrong with your EQ. It has much bigger lows than the vast majority of bass cabs but the speakers do take some time to run in. The last thing I want is a semi-satisfied owner, so I suggest finding something to replace it and then let me know when you want it collected, obviously at your convenience. If you'd like a refund before you send it back so you can buy whatever else you choose, then that's fine by me as long as I get the cab back relatively soon afterwards! Alex

[quote name='EBS_freak' post='684092' date='Dec 14 2009, 03:34 PM']Now this is interesting. Two different values for Vd. Just shows that it's open to interpretation - how can you guarantee that manufacturers are calculating Vd in the same manner?[/quote] I've already explained the different ways Vd can be calculated, please re-read my previous posts. It is easy to standardise this as if Klippel based values are not provided you can use the arithmetic explained in my last post. The alternate methods are within 10% which is a perfectly reasonable tolerance but if you want to be more precise then ask the manufacturer for the voice coil length and the gap height so you can do the sum yourself. Alex

Updated data so you can compare apples to apples. Using the modern mathematical method seems to give a slightly optimistic figure but it's closer to reality (Klippel based figure) than the pessimistic figure given by the older mathematical method. Klippel method: Midget = 330cc Compact = 505cc D.M. = 660cc Big One = 846cc Vintage = 1010cc Newer mathematical method: Midget = 340cc Compact = 566cc D.M. = 680cc Big One = 915cc Vintage = 1132cc Newer mathematical method is: Sd x (((Hc-Hg)/2)+(Hg/4)) = Vd where Sd equals cone area (Pi x D^2)/4, Hc equals voice coil winding length (or height but definitely not diameter) and Hg equals magnetic gap height (or length or depth depending on your perspective). Alex

[quote name='WonderHorse' post='683975' date='Dec 14 2009, 01:47 PM']I don't think I'd fair too badly tbh. At practice and at smallish gigs I don't turn the amp past halfway and that gives me PLENTY of sound.[/quote] Unfortunately my experience with most Trace heads is that halfway on the volume is pretty much full power - after that point it just gets dirtier as it clips on louder notes. [quote name='WonderHorse' post='683975' date='Dec 14 2009, 01:47 PM']Would the DOuble Midget be the same?[/quote] The D.M. will be significantly louder in the mids and highs (probably as loud as the Marshall) and a bit louder in the lows, so it depends on how much bottom you need. Sensitivity in the lows is directional proportional to enclosure size (assuming equal LF cut-off - and I'd expect the Marshall and the D.M. to have similar bass extension despite the very different drivers and alignment) so with only a few watts big lows need big cabs. Alex

I'd expect your VBC412 to be as sensitive as two Compacts or one Vintage - it's an ideal cab for getting lots of SPL out of few watts. A Vintage will handle lots more power and thus go quite a bit louder in the end, whilst with a powerful aggressive amp a Compact might get quite close to the VBC412 at full (clean) blast. Anyway, I'd guess a Compact would be about as loud as half your current cab - so how do you think you'd get on if it was a 2x12", not a 4x12"? Alex

[quote name='Moos3h' post='683049' date='Dec 13 2009, 03:08 PM']I'm looking forward to trying the loaner when it makes its way over here, but wonder if I'd have to consider running into the PA too, if it's that directional?[/quote] It's noticeably less directional than a 4x10". Alex

There's a spec which I don't think I've ever mentioned before on this forum, which really nails down the benefit of the Acoustic 4x15". It's this thing called Vd. By doubling the driver count compared to a 2x15" you double the Vd. As amps were getting more powerful in this era but excursion limited power handling wasn't keeping up this solves the problem by halving the enclosure volume per driver and thus reducing sensitivity (and consequently decreasing excursion per volt and thus increasing power handling) in the lows whilst also doubling the ability of the cab to move air (that's that Vd thing again). Fast-forward thirty years and you can get 15" 'full-range' drivers with significantly more Vd than two of the drivers from a 408, so a 2x15" will play louder than ye olde 4x15" - and because you're not doing the twice as many drivers in the same box trick you also get better sensitivity in the lows. Vd, never before did you think you'd want more of those two letters, did you? Alex P.S. That eBay cab looks quite a bargain if you're local!

I think any of the cabs will work well with acoustic or electric upright but that's very much subject to how you pick up and amplify the sound of the instrument. With an ideal pickup and amp then the more accurate the cab the better - but often bassists will get a good amplified sound by having an amp/cab whose colouration compensates for the inaccuracies of the pickup. Alex

It really depends on how loud you play and how clean and bassy a tone you like. What cab are you using at the moment? I know for me to get the loudness I'd want out of so few watts I'd want something big like a 6x10"/4x12"/2x15", at which point it makes more sense (for me) to get more power and thus have to carry less cabbage (sic). Alex

[quote name='wateroftyne' post='682222' date='Dec 12 2009, 03:09 PM']I gigged the Compact last night (I've used it a few times, but this was the first a gig volume), and had exactly the same phenomenon. The E was fat and puncy, but the D & G were almost MIA. Mind you, I'm used to having my old cabs at ear level, and the compact was down on the deck.[/quote] That makes a big difference! But also bear in mind that your HS210s have low Xmax drivers so they add a lot of harmonic distortion at relatively low levels. Alex

Hi Ben, You're not the first and you certainly won't be the last to have this 'problem' when switching to a Compact. What's happening is that the Compact is cleaner throughout its range, smoother in the mids and a bit deeper in the lows than your old 4x10". The cleaness of the sound is the biggest difference, because the higher harmonic distortion of the 4x10" adds a load of extra midrange which adds punch and growl to your sound. So what's the solution? You need to get that punch and growl happening with your bass and amp. Many bassists think that the neck pickup gives the most bassy sound, the bridge pickup the most midrangey/trebley sound and thus if you have both pickups on you gets lows, mids and highs in equal quantities, because it's an average of the two sounds. However, that's not actually what happens. Because the pickups are in different locations there is a phase difference between the two signals, and so instead of getting simple addition of the sounds you get a mix of addition and subtraction. The subtraction happens in the critical midrange area and the further apart the pickups are, the bigger the midrange cut tends to be. So if you want a nice fat grunty sound with plenty of mids, especially lower mids, use the front pickup soloed. If you want a growly aggressive biting and more compressed sound use the back pickup soloed. If you want a mellower sweet round sound that sits back in the mix then use both pickups up full. And then as you roll back the volume on either pickup the midrange scoop will decrease until the sound eventually gets back to the sound of the soloed pickup. That's the first step in getting the right sound out of your bass. You can then mess with that with EQ but bear in mind that EQ will shape the sound but it won't fundamentally change the character of the sound unless you do something drastic. One of the perils of active basses is that many bassists add far too much bass boost when they'd be better served by leaving the lows flat and simply turning their amp up. That gives you more fatness and bottom whilst also maintaining your midrange punch. Same with amp EQ - go easy, and turn that contour control right off. The perfect sound at home is never the perfect sound in the band - the perfect sound in the band needs way more midrange and top because they get masked by the sound of the other musicians whilst the lows have their own space so sound louder as there are no sustained sounds competing with them. If this doesn't give you back that D and G string punch then you need to adjust your pickup heights. The best way to do this is to set your EQ flat on bass and amp, turn the neck pickup off and then raise the bridge pickup and balance the heights until notes both across and up and down the neck are equally loud. If the notes warble as you go higher on the low strings then lower the pickup until that stops happening. Then solo the neck pickup and raise it until the notes are as loud as with the bridge pickup soloed. If you find the strings start hitting the neck pickup then lower it and bring the bridge pickup down to match. It does take a fair while to do this right. Also bear in mind that as you turn up your amp your low strings will sound louder due to the human ear's deficiencies so when tweaking your pickups errr towards having high notes and strings louder. Take a suitable screwdriver to rehearsals for final tweaking in the context of the band. Let me know if that makes sense and let me know how it works for you. You'll probably find yourself using much more soloed pickup sounds and you'll notice that by getting the tone from your bass and amp rather than relying on cab colouration that when you're DI'd at gigs all the soundman has to do to get a fantastic bass tone out front is to roll off some treble to match the natural roll-off of the Compact. Alex

[quote name='bigfatbass' post='681527' date='Dec 11 2009, 05:24 PM']But to get back on topic, in the very first post of this thread Alex said that the figure Celestion quote for Xmax is wrong. So if there is not a consistant measure for Xmax it reduces Vd to a meaningless number. Doesn't it?[/quote] Fortunately not! Every speaker manufacturer knows the gap height (Hg) and the voice coil length (Hc) of their drivers. With those two pieces of data you can recalculate Xmax in the modern mathematical way, which simply involves adding Hg/4 to the old Xmax number (Hc-Hg)/2. THe resulting mathematical Xmax works out sufficiently close to the Klippel analysis (Xmax where THD=10%) method. [quote name='bigfatbass' post='681527' date='Dec 11 2009, 05:24 PM']Given that most cabs use the same drivers, they may be custom OEM versions but my bet is that in most cases the customisation involves sticking the cab makers label on the drivers, then any cab with Eminence, or made to our own specification by Eminance, will have the same Vd? Am I missing something?[/quote] Nope, you're absolutely right. Same for Celestion, B&C etc. If a manufacturer has asked for a longer voice coil (as with the Avatar DeltaLite 10s) then they can tell you that number and you can recalculate Xmax (a different Hg would involve a whole new motor). I'm sorry some people have been offended by the moderation, I'll be sure to make any further potentially contentious statements (I'm still astounded that such an argument ensued) on my website in future. Alex

Should we just delete the whole thing and start again then? Or should I just write this on my website, you can all read it, and then you can agree or disagree without having an online argument about it? I mean honestly, I am just trying to help simplify the process of choosing a suitable cab. If it doesn't have enough Vd then you can cross it off your shortlist. Then go and try the ones that do. And I guarantee that the ones without enough Vd might have impressed you in the shop but would have turned out to be a horrible disappointment on the gig. Yes, you have to try a cab to find out if you like the sound, but are there really enough hours in the day to try every cab on the market before making a decision? Vd is a good spec to narrow the field. In fact it's rather like doing the "I want a 4x10" thing except it removes the risk of getting a sub-par 4x10" with insufficient Xmax (and thus Vd) and also broadens the field to other cabs with similar output whose tone you may or may not prefer. Alex

[quote name='sk8' post='680415' date='Dec 10 2009, 05:01 PM']i was wondering why i could only see EBS_freaks posts as quotes in other messages and not in the thread[/quote] I just wanted to make him feel welcome, he loves a bit of moderation (which of course should only be in moderation). Alex

Hi Wil/Disgusted Of Bristol, I've left in everything that's relevant and removed that which wasn't. If you want to start a thread on those subjects elsewhere then feel free. I simply don't want a potentially useful and educational thread to be filled up with off-topic arguments which distract from the matter in hand. If you look back you'll see that I've left in plenty of useful points from those same people whose other posts have been edited/deleted. Alex

[quote name='Rich' post='680210' date='Dec 10 2009, 01:20 PM']So to use a motoring metaphor, judging a cab purely on things like sensitivity and frequency is a bit like judging a car purely on horsepower and 0-60 time... the first car has more horse and a quicker 0-60, but when you look closely at the second car it has more torque and a better 30-70 time, which in reality is far more useful. Have I got that right?[/quote] Yes, that kind of thing! Midrange sensitivity and thermal power handling are critical to get the mids loud enough, so very important with PA tops, but with bass guitar we tend to run into problems when it comes to producing lows, and because our cabs generally have to produce the mids from the same speakers as the lows, when the speaker starts struggling with the lows it also screws up the midrange. Yes, most of the tone is in the mids but if you can't produce enough lows to support those mids then it won't sound like a bass. You know how everyone goes on about how you can't get good bass out of a guitar speaker? Well actually you can at low levels from a closed back cab like a Marshall. But as you turn up the lack of Vd does you in and it all gets grindy and distorted and eventually speaker death happens. Alex

[quote name='bigjohn' post='680153' date='Dec 10 2009, 12:42 PM']Absolutely - it would be good if this was done independently. Some kind of kitemark type system.[/quote] Never going to happen sadly, it's too small a market sector. But as I've said over and over again thermal power handling specs are supplied by the manufacturers and 99% of them are honest and accurate. Not terribly useful but they are truthful. And Vd specs are just as straightforward and can be supplied to the cab manufacturers by Eminence, Celestion, B&C, etc, unlike sensitivity and frequency response claims which are open to interpretation. It is just a single number which is derived from cone area multiplied by cone excursion - there's very little wiggle room to bs or 'massage'. Alex

[quote name='bigfatbass' post='679724' date='Dec 9 2009, 11:24 PM']When I was young(er) all the the hifi and music equipment mags (International Musician) used to conduct lab tests. They used to publish test results and measured cab performance in an Anechonic Chamber (basically a padded cell) and produce frequency response and max SPL charts etc. The reason this kind of reviewing fell from favour was because I often read in these magazines that stuff measured great but sounded bad. So reviewers started trusting their ears rather than their oscilloscopes.[/quote] If something measures great but sounds bad then whoever is testing it is testing it wrong or misinterpreting the data. An easy mistake is to believe a simple SPL plot because these are often taken with a pink noise burst and so a seemingly perfect flat plot might only be flat because distorted overtones are filling gaps. Like a cab might have a dip at 250Hz but the woofer generates particularly high 2nd order harmonic distortion at 125Hz which thus synthesizes a load of extra 250Hz energy and fills in the gap. But it won't sound anything like a cab which has low distortion at 125Hz and even response at 250Hz, even though the SPL plots will be identical. [quote name='bigfatbass' post='679724' date='Dec 9 2009, 11:24 PM']Alex is right and specs are important, but they are only part of the story... ...The same is true of cab design. Computer models should be checked with testing in an Anechonic Chamber.[/quote] Absolutely. Design, model, build, measure (I do this outdoors in half-space as anechoic chambers big enough for bass are rare and expensive), re-design and model, re-measure, etc etc. It's a pain in the neck but the sad fact is that unless you have the budget of a Formula 1 team you are never going to come up with sufficiently accurate models to get the finest details right. Fortunately you can model and measure and compare, and then you can mentally figure in the inaccuracies of your modelling which gets you closer to the desired result with each iteration. [quote name='bigfatbass' post='679724' date='Dec 9 2009, 11:24 PM']Basschat is providing the beta testers for Barefaced, but I am not entirely convinced the testers have the expertise and experience of using lots of different gear necessary to perform the role.[/quote] I've certainly had useful feedback from other basschatters but I also have myself and plenty of other customers who were not on basschat when they went Barefaced (though many are now). But the design decisions all come down to me and I may not be the greatest bass player in the world (though I'm better at playing my way than anyone else ) but I do have an almost autistic ability to dissect and analyse sound and then apply those learnings to loudspeaker design. Alex

[quote name='Wil' post='679384' date='Dec 9 2009, 06:57 PM']I have to say I wholeheartedly agree with his sentiments about testing the merit of a cab with your ears. I do see the place of the science behind cab building but I also know I love the sound of the apparently poorly designed Ampeg 8x10 at full volume, much as I also like old British motorcycles despite them having a tendancy to fall apart if looked at too hard.[/quote] You absolutely HAVE to test a cab with your ears AND it has to be at the required SPL. That's why I have a one month trial period. The Ampeg 8x10" was a great design for the era, that's why it was such a success. And one of the big reasons why it was such a success was that it had more Vd than any other bass cab up to that point. If you like its unique sound (which many many bassists do) and you're happy with the size, weight and cost, then there really is no reason to consider using anything else. For some of the stuff I play it would be spot on tonally - but then for other stuff it wouldn't, and I hate being boxed into a tonal corner with my own gear (though I love using other gear at jams which does make me focus on one particular facet of my bass personality). But let's say you're looking to replace your current big cab which is loud enough for your band but you know it won't go much louder without sounding nasty. Let's say the manufacturer has kindly told you that the Vd is 600cc. You then know that you can ignore every cab on the market whose Vd is much below 600cc, and you also know that you don't need to go much higher than 600cc to get the required output. There are a LOT of bass cabs out there, so doesn't it help to be able to narrow the field like this before you go and try all of them at rehearsals/gigs? Alternatively you could look at the other specs of your cab (lets assume it's a nice 6x10"). Power handling 750W. Sensitivity 102dB. Now if you used the power handling spec to eliminate cabs that weren't powerful enough you'd end up with a list that still included a fair few 3x10" and 2x12" cabs which on the whole are unlikely to cope. Or using the sensitivity spec (which is the most abused one) you'd end up still including even some 1x12" and 2x10" cabs which wouldn't have a hope. And if you're quite new to bass playing you might even believe the specs, try a small cab with insufficient Vd in a shop and conclude it sounds great and that the specs tell you it'll be loud enough, and then have an epic fail at your first rehearsal. The other approach would be to try to get excursion limited power handling figures and low frequency sensitivity figures for everything. But once you have them you then need to use logarithms to work out the resulting max SPL, which really isn't rock and roll. But I think everyone understands cubic centimetres (ok, apart from the Americans... ) Alex

[quote name='Rich' post='679876' date='Dec 10 2009, 07:55 AM']Call me a bit of a luddite, but the only specs I tend to look at these days are power handling (just to make sure the amp doesn't woefully over- or under-power them), impedance (amp compatibility), sensitivity (for a rough guide to 'loudness', and yes I admit this is possibly a red herring) and weight. Especially weight. I made the decision to have a go with the Nemesis 1x15s based mainly on back-friendliness! Obviously there will be many folks who will eagerly want to know every single spec, almost right down to the designer's preferred socks. For this reason alone, maybe it's worth researching. But there will also be many of us for whom 'Vd' will really only ever be something we sniggered about in the playground when we were 12.[/quote] Hi Rich, I'm going to turn this into a useful example. Let's say that when you were looking at your Nemesis you were also looking at another cab. Here's the specs for the Nemesis (assuming this is the right model 15, they've been through a few different models): Power Handling 250 Watts RMS Freq. Response 38hz - 18khz Impedance 8Ω Sensitivity 100dB SPL@1W1M Weight 42lbs And lets say you were looking at another cab with the following specs: Power Handling 350 Watts RMS Freq. Response 35hz - 18khz Impedance 8Ω Sensitivity 101dB SPL@1W1M Weights 48lbs So you might think so yourself, well the latter cab is a bit more powerful, a bit more sensitive and goes a bit lower, so it's worth the extra weight. But let's assume that Vd was also quoted. For the Nemesis = 350cc For the Brand X cab = 250cc This means that despite the Nemesis looking like it'll be less loud and fat according to the original (and very open to marketing abuse) specs, it will actually produce greater low frequency SPL. Alternatively you could have an excursion limited power handling figure added to the specs (which would be likely to show the Nemesis as having more) or a true low frequency sensitivity figure (ditto). The product of these two figures would show the Nemesis as having better performance. Alex

To be frank I really can't be bothered with petty arguments on this forum so despite my dislike of moderation I've decided to tidy things up. For anyone that just wants to leap in and have a dig then I'll be doing this in future, so save yourself some typing. Just to clarify things further, Vd is an equivalent spec to a true sensitivity spec added to a true power handling spec - it tells you how loud a bass cab can play. If you're in the pro audio (SR) world then you are provided with accurate sensitivity specs and accurate power handling specs which give you the same end result. No large PA subwoofer rig would be put together for a gig without using these specs to ensure the dB requirements can be met. And as it's much more complex to get sensitivity and power handling plots from every manufacturer, Vd is a simple shortcut to essentially the same end result. More Vd equals more dB SPL where it counts. Strange that this should create such an argument as it's a bit like suggesting that van manufacturers should start quoting loadspace volume rather than just 0-60 times and top speed - it's the most useful spec for BASS players. Alex

[quote name='EBS_freak' post='679327' date='Dec 9 2009, 06:09 PM']Not really. Vd for a 12 inch speaker in a box measuring 13x13x1. Vd performance... great. Now tell me about the rest of the design. Extreme example I know but you get the idea.[/quote] Your extreme example merely proves how ill informed you are and why it's futile to argue with you. Within the spectrum of bass cabs, from 'undersized' Schroeders to the 'oversized' Big One, Vd remains entirely relevant and applicable. Sorry but it really is useful and judging by all the other responses I'm not the only person to think so. Alex

[quote name='EBS_freak' post='679298' date='Dec 9 2009, 05:50 PM']But the real spec isn't measurable if the cab design is not right - and no manufacturer is going to own up to that. So naturally, they will publish a Vd that makes them look favourable against their competitors. It's not all down to the choice of the speaker... as mentioned earlier, speakers and cab both influence the tone and volume of a cab. What the point of publishing the Vd if the speakers are in an wrongly sized, wrongly ported box... what about phase cancellation due to poorly positioned drivers... they all effect volume and tone.[/quote] This entirely proves that you don't understand what I'm talking about. And if you think WinISD is all I use to design my cabs then you are WAY off the mark. Vd is a no bs figure. Xmax times Sd. That's it. If the box is tiny or the box is huge, the Vd is still the same. Alex

The thermal power handling spec quoted is actually accurate - not useful but accurate. And it's simply the sum of the voice coil power handling figures as supplied by the speaker manufacturer. Those same speaker manufacturers can likewise provide accurate Xmax figures, either by Klippel analysis or by doing the voice coil length and gap height sum. And cone area is pretty damned obvious (but it's always less than you think because of the diameter lost to the cone surround and frame). We play bass, we care about bottom, about moving air. You want a big bass sound, you need to be able to move air. The Vd is simply the amount of air the cones can move on one stroke, in cubic centimetres. It's nice simple maximum output spec. Isn't that much more useful than knowing how much heat you can pump into a cab without it blowing? Alex