LawrenceH

[quote name='geoffbyrne' timestamp='1322525064' post='1452277'] I mean, where does that leave my son, having done 5 years at music college & come out with an LRAM & later a BMus? I suppose he'd better just saved all my cash & got a couple of turntables, then? [/quote] Depends if he'd then practiced them through his childhood, got up to a decent standard and then spent 5 years REALLY practicing, like you do at music college! He'd be pretty good then I reckon, probably make a very tidy living (not that I've noticed orchestral musicians doing badly, quite the opposite in fact). Lots of late nights though...

[quote name='brensabre79' timestamp='1322582493' post='1453094'] But that doesn't mean you have to get a Behringer desk. Spirit, Mackie, Yamaha, Studiomaster etc. etc. all do little club mixers. Don't forget though if you need reverb and its not included in the desk you'll also need outboard. [/quote] I have to say, I own plenty of cheap and cheerful Behringer stuff so I'm not snobbish about it...but I've had desks by all those brands, and I must say the Yamaha has sounded sweetest, closer to say Allen and Heath (a proper 'mid-level' desk) than a Behringer. Oh yes, I definitely agree about keeping the bass out of the PA.

Until you prang the speaker cone with a mic stand or something then it's fine

[quote name='fatback' timestamp='1322574550' post='1452848'] I use one Midget on a stand for my upright (to avoid feedback), but seem to lose a good deal of low end volume that way. Wondering if a second Midget in front of me would give me the extra oomph I feel I need. But would that cause any kind of phase problem? Haven't a clue about these things, so your thoughts much appreciated. Amp is an EA Doubler 550. [/quote] Separating bass speakers is generally a bad idea...witness the classic 'corridor of bass' when bands use the one-sub-a-side setup for PA - gives a very uneven, location-dependent response. For controlling feedback without losing low-end you may be better off using something like a gramma pad that keeps the speaker low down, and/or putting the pin on something that provides similar isolation. Mechanical coupling to the floor is different to acoustic coupling obtained by being close to a surface. This will only work if firstly it is not mechanical coupling that is giving you the low end (tends to be 'boomy' and centred on a particular frequency) and secondly if the sheer volume of the low-end isn't what's causing the feedback. In that case you may have reached the inherent limitations of double bass and need to look into notch filters or foam inserts on the bass itself, I seem to remember Clarky had a thread discussing this?

[quote name='Walker' timestamp='1322553115' post='1452358'] Yes, this does look like the route we are going to go down now, just a bit of persauding to be done Although we are going to pick up a small 2nd mixer to submix while we raise the £££'s for a new Yam powered desk. Thanks everyone for your input (boom boom). Chris [/quote] If you're after something cheap and 4 mic inputs is enough, this looks a good price [url="http://www.ebay.co.uk/itm/Yamaha-MG10-2-Mixer-Excellent-Condition-/250941065971?pt=UK_Mixers&hash=item3a6d40caf3"]http://www.ebay.co.u...=item3a6d40caf3[/url] I have one and I'd say it's decent.

[quote name='TimR' timestamp='1322519197' post='1452153'] Where did this spring from. It's a 3 year old thread! [/quote] Haha! I'm always surprised people like this as a song, everything about the vocal is so spectacularly dull.

[quote name='KimKG' timestamp='1322468791' post='1451033'] I'm curious, why is this a bad plan? Is the 1x15 more likely to blow in this situation? Kim [/quote] Mainly because you're asking a single motor pushing a surface area of about 850cm2 to keep up with 4 motors pushing a total of nearly 1400cm2. The 15 will probably have higher excursion capability so net volume of air capable of being moved (Vd) will be less unequal than these numbers would suggest, but thermal power handling is likely to be greater with the 4x10. If you're playing at real cooking volume you might even fry the 15 without really noticing. Having said that a better quality/higher power 15" in the OP's situation would probably handle it. There is another issue which is whether the cabs are well-matched in terms of output phase alignment, which means using two identical cabs is often preferable if you want to ensure low-end output is uniformly louder compared to a single cab.

If the cabs don't have a crossover it might be worth trying one, or even just disconnecting the piezo altogether. Because I could fairly easily, I'd try an active crossover/bi-amp set up just to see what effect that had - would that be an option? If the piezos are operating too close to their resonance apparently this can make them sound pretty nasty, having said that I've never heard one I actually liked...

[quote name='soopercrip' timestamp='1322422803' post='1450720'] This is a link to alocal Hull based aluminium supplier I used to trade with. [url="http://www.eltheringtongroup.co.uk/"]http://www.eltheringtongroup.co.uk/[/url] Dont know if they stock the punched grille stuff your looking for, but they have always been helpful and might point you where to go. These are another local ali company but never used them, again they might know a source. [url="http://www.aalco.co.uk/"]http://www.aalco.co.uk/[/url] [/quote] Cheers Andy, much appreciated! I will check these options out

[quote name='icastle' timestamp='1322403470' post='1450370'] What complexity? All we do is feed the drum mics into the little mixer, balance everything on that and set up EQ - we then feed that signal into the main desk on a single channel that we just leave set flat. [/quote] I concur, it's not really much extra bother carrying a multiway socket and two cables. But a better mixer is, well, better, so it really depends on the relative costs and the likelihood of further expansion in future. I don't like powered mixers because of this problem of effectively tying you into buying a new amp if you decide to upgrade in future, but for portability they are hard to beat. I do find an extra small-format mixer is a pretty useful item to have in any case, so the relatively small cost of a new mixer is not a total waste if you upgrade later.

This is going to be a bit of a slow build thread, since I can't get started til Christmas, but here are some box sims from WinISD comparing the performance of a pair of NTR10s (blue) to a pair of Deltalite 10s and a single 3012HO or 3012LF all in the same overall box volume, tuned to 52Hz. Note that excursion charts are plotted for 500 watts input which the 8 ohm single drivers wouldn't see and it exceeds their thermal limits in any case. Similarly max spl chart ignores the fact that I couldn't put more than 300w into the 12" drivers with my F1. [attachment=94046:maxspl.JPG] [attachment=94047:cone-ex.JPG] [attachment=94048:transferfunc.JPG]

I have been intending to do this for ages, but up here in Edinburgh I don't have suitable tools or space. However I'm off to the parents' for Christmas so will finally get a chance to build these - a pair of ultra-portable 1x10" speaker cabinets to go with my nice and light Markbass F1 head. A lot of the basic design decisions have been made, but further input from the helpful people on here will be very gratefully received, particularly in relation to finish, internal acoustic lining and hardware. (Disclaimer!) the design brief is fairly specific to my needs, and I'm hoping the end result will suit ME better than excellent commercial offerings from eg Barefaced and EAD on here. I'm in no way trying to rival their products as I have neither the knowledge nor resources! Driver choice: Rather than follow the sensible herd and build a design based around Eminence drivers (despite having 4 deltalite II 10s kicking around!) I have gone for the Celestion NTR2520D which I picked up at the very reasonable new price of £160 for a pair. Am I mad, or just stupid?! Hopefully neither, since I've bought them already...but why? - First, all else being equal I prefer two 1x10s to a single 1x12. There is a minor advantage in terms of single driver dispersion characteristics but far more importantly, although two together will weigh more than a single 1x12, quite often I won't need more than one - especially for rehearsals which I typically reach by bike! Plus at the light weight we're talking about, it's actually form factor that will make more of a difference to me and two smaller boxes are preferable. - Second, performance. Based on spec a pair of the Celestions will at least equal the Eminence 3012HO in the low-end and in my specific set-up should slightly better it, since I'll get the full 500 watts out of the F1 running at 4 ohms versus 300 at 8 (and this still won't exceed thermal rating). In fact there is no real advantage for me to be gained by going to a 3012LF plus separate mid, which with the crossover would incur a significant weight and price penalty (though sound very smooth). The Celestions have a nominal Xmax of 4mm BUT as mentioned in other threads, this is based on the traditional conservative calculated method rather than measured. More importantly to me, Celestion have confirmed that Xmech is an impressive 13mm with suspension braking kicking in at 10mm (very audible farting-out). This compares favourably to other 10" drivers (Xmech on the Deltalite II 2510s is 8mm). In the absence of Klippel distortion measurements (which according to B&C are rather ambiguous anyway) I'm going with a practical Xmax of 6mm for my sims, using (Hc-Hg)/2 + Hg/4 as Alex suggests on his site. In any case it's a bass cab, not a hi-fi . The other main advantage to the Celestion is that it should give a rather more balanced frequency response, many of the Eminence drivers tend to have quite an extreme on-axis peak between 2 and 3k. This can give a nice voicing to a bass guitar but it depends what you're after and how it interacts with the pickup resonance peaks of a particular bass. I'd rather get the voicing from the choice of bass/pickups and EQ if necessary. The Celestions extend up to about 5k on-axis and lack that big spike. This is why I've chosen the 2520D over the 2520E, which trades upper-end sensitivity for a longer voicecoil (and hence greater Xmax). If I were to build with a tweeter I'd consider using a decent waveguide-mounted comp driver crossed low with steep filters, at 2k or so, and then I'd use the 2520Es, but for weight and cost I'm going for a 1-driver solution. A quick note, there are other 10" drivers out there from the likes of Ciare, Faital and B&C that look very capable but they are generally more expensive and significantly heavier, with the performance benefits irrelevant when powering them with a single 500 watt amp. Cab size and tuning: I'm playing 4-string jazzes and always use standard tunings so I really don't care about performance below 42Hz (string thump aside). Cab tuning tends to be a trade-off in terms of mid-bass versus low bass volume and excursion. The lower you tune, the more excursion and less volume around that important first harmonic (80-100Hz), which on a jazz is typically stronger than the fundamental. In a small box as well, too low a tuning requires very long ports to get sufficient area. Playing around I've gone for ~35 litres tuned between 50 and 55 Hz. This models well with the Celestion and avoids that exaggerated hump around 100-120 that you typically see on small cabs that are designed to sound 'deep' at low volume, which I personally don't like. The size is a good balance between bass-response, portability and excursion capability giving ~55Hz @ -3dB and 42 @ -10dB. It's no fEarful but it should have some decent poke. Construction: I've found a supplier for poplar ply at a better price than I've seen elsewhere, which might be useful to anyone else contemplating a build [url="http://www.timberdepots.com/index.php"]http://www.timberdepots.com/index.php[/url] For some reason I was actually charged less than list by the very helpful guy in the Saltash branch, and 2 full sheets of their quality 12mm poplar are now sitting in my dad's garage which should cover a few more builds after this! To save the good stuff I will probably build a prototype using nasty B&Q ply. This'll be good to test bracing schemes if nothing else! I want to use a shelf port to take advantage of the extra bracing, and benefit from the reduced length typically required compared to tube ports, but it does make calculating the length required a bit more complicated. I'm also currently thinking I'll go against convention and convenience and mount the driver from behind the baffle. Not without disadvantages but I have my reasons... Finishing and hardware: This is where I'm most unsure. I've used a UK-sourced Duratex-alike substance before and been less than impressed, perhaps there's a knack to applying it. I got a quote from a local company that spray polyurea for lining horse boxes etc (line-x type stuff) but for just two boxes as a one-off they'd charge £100 (it gets much cheaper for more cabs) and from what I understand the added weight is actually quite significant. I think this is probably the finish David Perry uses for his EAD cabs and it's incredibly tough stuff, but I'm not sure I want to spend that much only to add nearly a kilo to each cab. Currently I'm wondering about carpet or vinyl for either a retro look or something a bit more 'unique'. I'd also like to incorporate a tilt function and am undecided as to the best way of implementing this, but more on that closer to the time. Finally, I'm not sure on grille material. High void % aluminium is probably the best option for weight v strength but I can't find a UK supplier.

[quote name='JTUK' timestamp='1322395605' post='1450201'] If you sub-mix, you loose individual control of that signal...and therefore you only have collective control on the sub group. Some might allow EQ on that group but some might just allow just gain. [/quote] Not necessarily an issue if you're sub-mixing with another desk that replicates those controls though - it just mimics a grouped desk module which on a lot of gigs you might do anyway. If I'm using something like a GL3300 with group options and mixing a larger band, I'd often group vox as a stereo pair for convenience.

[quote name='M-N-Y' timestamp='1322341953' post='1449763'] Sorry but this one betrays my funk roots. Awesome bass playing though IMHO. [/quote] Not generally a fan of the later Jamiroquai output but that is awesome! Great distinctive bass sound too.

[quote name='alhbass' timestamp='1322311462' post='1449190'] Below are two short sound files, recorded at band practices with the same gear in the same room, same eq settings etc - the only difference between the set ups is that on the first occasion I just used the one cab (on the floor, tilted up towards me), and the second time I stacked both. [/quote] They sound quite similar to me, but then I'm only listening on rubbish laptop speakers! There are two main things I can think of (other than room acoustic effects due to cab placement alterations but I'll ignore that for now). First, from the sound of it the overall volume of the bass is pretty similar on each clip. Depending on how hard you drive the cab, you might expect some tonal change. If on the gig you play louder then it'll get closer to the sound of a single cab as you push them harder and they start to distort to a similar degree. Second is the way that two cabs combine. They will be louder but only in the lower frequencies, above a certain point which depends on the driver spacings the wavefronts no longer effectively combine. You get more complicated lobing patterns in the freq response depending on listener position, but the overall effect is that the sound gets a bit more bassier/middier. I think I can hear this on the recording - you have effectively EQ'ed up the bottom end of your rig. I'd suggest giving the upper mids/treble a bit of a boost to compensate for this, and not bothering using both cabs unless you need the extra volume.

[quote name='Count Bassy' timestamp='1322243491' post='1448606'] NOTE: Just checked and the choice is actually 17 or 24dB (rather than 22dB). Apart form that the question remains the same [/quote] I think for bass, less is better in terms of balance - since all the low stuff isn't really altered by the plugs it can get a bit boomy. I have the ER15s and it's plenty. 15dB is still less a very big attenuation in terms of power, about 30-fold! My mind always boggles at the thought of bands where 15dB isn't enough to protect the hearing, they must be just insanely loud.

[quote name='brensabre79' timestamp='1322229817' post='1448282'] Thanks guys, I was looking for a 2 x10 though. I don't think £500 is a meagre budget though, so the two I choose is Light/compact and good :-) [/quote] It is, however, rather on the meagre side to get a 2x10 that can match the output of a 4x10...and it still won't really sound like a 4x10. Markbass' larger 2x10 is probably one of the closer lightweight cabs in terms of midrange efficiency but I'd doubt it has the low end to match (although pretty reasonable for a 2x10). EDIT: I see you're talking about an SWR goliath ii...in which case you will not find a single 2x10 on the market to match the low end.

[quote name='muttley' timestamp='1322225912' post='1448190'] Interesting. I had a look at the datasheet for the driver mentioned by the OP but didn't notice the definition of Xmax (basic arithmetic, Klippel, or otherwise). [/quote] It's only defined on the datasheets for their 'pro' range PA drivers, but the voice coils and gap depths all strongly imply that they use the same calculation for their bass ones too. Interestingly, using the arithmetic method favoured by other manufacturers (Hvc - Hg)/2 + Hg/4 that particular driver clocks in at 4.5mm. Alex's very helpful Vd figures on his site suggests that for the Eminence drivers this value is close, but a bit optimistic compared to the distortion method, whereas the B&C drivers mostly meet or exceed it. Where these Celestions sit, who knows? But personally I'd choose this driver over the green labels for the midrange response, without losing any sleep over the xmax.

[quote name='51m0n' timestamp='1322217653' post='1448003'] In order to get as loud as they can you supply more power to the driver than for a 'normal' cab with similar drivers, so the drivers are slightly less sensitive (less loud for the same amount of power) but happily handle a great deal more power than a normal cab. [/quote] Hmm. I can't think of many drivers whose sensitivity is better than the nominal 100dB of these speakers. Even a pair of 10" drivers running at, say, 98dB sensitivity each (high for a 10") will only couple effectively up to a few hundred Hz so it ought to be at least as loud as the Hartke. The one issue I can think of is that I expect the BF use lower tunings than a lot of other cabs so you might lose a couple of dBs on the mid-bass 'hump', but I'd still expect the real-world difference to be marginal and would argue that's more of a voicing than a volume issue.

[quote name='JTUK' timestamp='1322220170' post='1448052'] Other substances might work better but access and availability...and price..? might be an issue [/quote] Isopropyl is indeed a better general solvent, as is acetone! Not entirely straightforward to get in quantity unless you happen to work in a lab though. Hmm, perhaps I should get into this string cleaning thing. All of these substances will contain water, I don't know how much is significant from the corrosion perspective.

[quote name='muttley' timestamp='1322216416' post='1447967'] I'm pretty sure the Celestion figure is based on Herr Klippel's machine (I visited the R&D facility a couple of years ago). [/quote] According to their datasheets, quoted xmax is still using the arithmetic method. Be interested to know if they have Klippel figures as well though! Btw I don't think Bill's 20% increase rule of thumb is necessarily accurate, if you look at the B&C 10CL51 for example it has a quoted Xmax of 6mm (Klippel) but an arithmetic Xmax of ~4mm. For the 10NW64 it's 8 and 4 respectively. They also claim the 10% THD is ambiguous and prefer Xvar, based on physical behaviour of the driver rather than output signal. It's perhaps pertinent that although Eminence rule the roost in bass cabs, in high-end PA it's a different story. For me, it just suggests that TS parameters are good for modelling small signal LF behaviour but to understand how a speaker performs at volume, easiest way is to build it!

[quote name='merello' timestamp='1322167926' post='1447578'] The 1970s ended, however, with possibly the greatest Precision Bass moment in all of rock history. [/quote] The supreme level of hyperbole in this statement is very rock ...nice article though!

I have an old pair of Celestion K300 12s which only have a nominal 2mm xmax...they sound fab on bass and have sufficient grunt that we have on occasion used them with active crossovers as stand-in PA subwoofers, a job they've done just as well as any other compact reflex box I've heard. I'm sure they're technically distorting away but you have to drive them HARD to make them audibly fart out. For musical instrument speakers one could argue that xmech is a more important parameter, along with the behaviour of the speaker on exceeding xmax. But this is not straightforward to measure or model. I don't think Celestion's designers are quite as clueless compared to the mighty Eminence as they seem to be made out to be in internetland - perhaps this comes partly from the very different relative costs of each in US versus UK. At £89, which was about what they used to be before prices went silly, they're pretty reasonably priced for a lightweight pressed steel 15" driver. £190 is clearly stupid and suggests Celestion may be effectively giving up on neo bass speakers for the time being other than for OEM replacements.

[quote name='Ghost_Bass' timestamp='1322072783' post='1446239'] Hi Laurence. To me it looks like that one doesn't lock on the open position, only stops [/quote] Yup that's right, but I can't see why that is a problem, all the force of the cab weight pushes it that way so it only has to stop in 1 direction. Good luck in your hunt though

[quote name='Ghost_Bass' timestamp='1321972351' post='1444951'] Yes, it's exactly like you described but it fixes the handle in the 90 degree at the same time. Tonight i'll take a picture of the one in my Promethean's cab. [/quote] So it looks like that one has a lock in both directions, holding it at 90 degrees or so. This should do a similar job, although these ones only lock in one direction this shouldn't matter if you mount the handle the right way round! http://www.penn-elcom.com/product/hardware/handles/elcom-recessed-handles/1851/306/ Alternatively I'm sure some of the surface-mount handles do the same.