Phil Starr

Power is power but of course not volume. Guitar speakers are generally more efficient at converting electricity into sound because they don't need long voice coils. Add into that the fact that our ears are much better at hearing sounds in the 300-3000hz range of the human voice and coincidentally electric guitar and you have the reason you can't hear so well. Also the guitar speaker sends out a concentrated cone of sound which usually points at the bassist and the vocal mics and misses the guitarist entirely whereas the bass radiates evenly into the room at the lowest frequencies. You shouldn't be worried about the guitarist other than to expect him to be a good band member and turn down. You only need to match the drums. The poor drummer doesn't have a volume control that goes to 11. If you match the drums than no-one should be louder than the pair of you. Get a stand for the guitarist to point his cab at his ears, he will probably have no idea how he actually sounds and 120w is too loud for most gigs never mind practice. Your own rig is overkill tbh but you seem to know where the volume control is, show your guitarist where to find his.

[quote name='Grangur' timestamp='1381419305' post='2238857'] Phil Starr - thanks I'm always happy to be corrected. If you can suggest a better position for the cap I'm sure the OP would like to know. (Me too) Cheers Rich [/quote] Sorry I think I may have created more confusion. If you want to put in a high(ish) value cap to smooth out the power supply to the pre amp this circuit is spot on. This is exactly the place to put the cap. The confusion I was referring to was over the value, so far the only value suggested was a 0.1uF connected across the switch terminals which would suppress switch noise in an AC circuit but is too small to smooth the DC voltage.

I think you may have come to the right place, think hard about what you want and a budget and we'll all help. I'll do the usual warning, if you think this is the best way of getting a cheap cab then you'd be better off buying something decent quality second hand, which will also be easier to sell to get some of your money back. You also won't know what your cab is going to sound like until you've finished by which time it is too late to change your mind. You won't make technical errors though if you take the advice from here, and people are very helpful. If this is about learning how cabs work and the pride in using something you have created then it's a great experience. You can get a good quality cab for a very good price too.

[quote name='alexclaber' timestamp='1380620797' post='2227845'] The driver in question is excellent for bass guitar. The damage is a clear case of both excursion and thermal overpowering. Most cheap bass cabs are tuned too high which means they'll unload on low note fundamentals. [/quote] [quote name='Bill Fitzmaurice' timestamp='1380630582' post='2228069'] +1. As is the case with any and all drivers it must be loaded into a cab that is compatible with its specs. If one is to push it to maximum output the amp must at the very least be appropriately high passed, if not limited to the driver's safe operating voltage swing. In terms of performance the 3015 is on par with an Aston Martin. [/quote] [quote name='R Baer' timestamp='1381186373' post='2235685'] +1 The 3015 is a great driver for a bass cabinet. Per the Eminence website "Recommended for vented professional audio enclosures for full range...." Full range would include a bass cab as well. Pretty much any driver can be pushed too hard into over-excursion, or fed enough power to burn out the voice coil. In my experience, there is a tendency for the term "super 12" or "super 15" to be taken as meaning these cabinets are capable of handling anything you can throw at them. Regardless of how well they perform, every cab does in fact has it's limits. [/quote] So it is absolutely clear that this speaker is a great choice for bass, Alex Claber, Bill FitzMautice and Roger Baer all agreeing, and full range does mean including bass. it is also clear that the damage was caused by over excursion from the photo's provided by Blue Aran. The big question then is: was this a suitable cab? To settle this I modelled the cab with WinISD using data from the Warwick website. The cab is just over 140l and tuned to 35Hz. The frequency plot is poor, the cab rolls off starting at 500Hz and is 6db down at bottom E. This is due to over damping from too large an air mass. A smaller cab would give much better bass. the crucial plot is the excursion plot however. If excursion is in excess of 11mm within the pass band then the failure is due to the cab design. If it is not, the failure is due to something else. I've attached the plot. This is with 450W power. The Warwick trace is in blue/green the other is Eminence's cab, similar in size to the Compact. You can see the unsuitability of the larger cab, the Compact sized cab keeps excursion within 6mm down to 35Hz the Warwick cab allows the excursion to rise to 10mm in the 'critical 60Hz region' meaning the bass will be distorted due to the misalignment of the port, which is tuned too low for this speaker. Both speakers exceed the damage excursion below 30Hz, though the Warwick is slightly better in this area than the smaller cab. This wasn't by any means a good choice of cab, it is designed for a speaker with a lower Fs and less well damped than the 3015, a smaller cab tuned to 45Hz would have been better. But, this speaker, in this cab using the full power of the SWR should not have been hitting the back of the magnet as it seems to have done. I guess it was out of manufacturing tolerance.

I really wouldn't want to use Danish oil on a fretboard. As you have been told they are a mixture of oils and solvents/drying agents but all the ones I've seen have also contained alkyd resins of the sorts used in gloss paint and varnishes, they do vary a lot though. I don't think I would use Tung oil either, too heavy. Unless you are prepared to do some serious research I'd stick to proprietary oils like Dr Ducks or ones based on lemon oils. They may look expensive but you use so little they cost almost nothing per application. My Dr Ducks has barely gone down in 5 years, maybe about a fifth and I have two guitars and three basses.

[quote name='Grangur' timestamp='1381391583' post='2238280'] This circuit should do it: [/quote] there's a little confusion here I think. the capacitor on a mains switch is there to prevent arcing and to suppress rf interference, you use a very low value to short out high frequencies and to present an open circuit or very high resistance to the 50Hz mains. If you want to use this circuit the capacitor needs to be a very high value as in this case it is being used to store charge from the battery and smooth out the peak to the pre-amp on switch on. Basically on switch on the resistance of the capacitor is low and all the battery current flows into this, as it charges the resistance rises and so will the voltage to the pre amp which will then switch on gently. This could present a problem, the capacitor is effectively shorting the battery when you switch on, some batteries can't handle high current flows well and this may shorten their life. You could put a small resistor in line with the cap if this is a problem. I'd start with a much higher value cap, something like a 10uF electrolytic, make sure you connect it + to +.

I do like horn designs, the higher efficiencies with everything working less hard promises a much better sound and just appeals as an engineering solution. Ported cabs suffer all sorts of problems with over excursion below Fb and I hate the idea of 4% efficiency. The trouble is the practicality of having the mouth area sufficiently large to get true bass from a moveable cab of course. In the seventies I experimented with lots of compromise horn designs like this W Bin. You just lose too much in the folds and the 80Hz lump is the best you can get, the short length really limits the efficiency gains too. The folded horn you show is great especially if you can use multiples or get them in the room corners. I experimented by having a forward pointing speaker loaded with a W horn at the back. This restored the directly radiated mids and gave me the nice upper bass hump and i sold a few for disco use as well as using them for PA at a few free festivals nut in the end I'm not sure they weren't just a glorified reflex design. Then Thiele/Small came along and spoiled the fun. My favourite cab of the time was the horn/reflex hybrid like the old Altec A7 [url="http://www.ebay.com/itm/ALTEC-LANSING-A-7-500-VOICE-OF-THE-THEATRE-SPEAKERS-NICE-PAIR-/141085231451"]http://www.ebay.com/...R-/141085231451[/url] and the tidier Eminence design [url="http://i384.photobucket.com/albums/oo285/audioblis/purple15hornloadedcab.jpg"]http://i384.photobuc...rnloadedcab.jpg[/url] I'd love to try these for bass sometime where i think the unusual frequency response might sound quite good, now there's something to do with your drivers

That's a blast from the past, I used these in the 70's for PA and built a few too. They were the bees knees at the time but i wonder how coloured they would sound now. They gave a good bass thump but you lose almost all the top end in the bends due to phase problems. They shouldn't be too critical in terms of replacement speakers, they aren't reflexed/ported so tuning isn't a problem and the horn helps load the speaker and so excursion is controlled. Getting them close to the ground will give you better bass extension, try them on their sides. how have you got on with them?

It's looking great, how did it sound at the rehearsal?

I hope this comes out. I've attached a file from WinISD with three plots of a Kappalite in three boxes. All three plots show the cone excursion with 450W going through the speaker. The yellow line is a 'standard cab' generated by WinISD but similar to the 'large vented box' on the Eminence website. The pink line is a smaller cab tuned slightly lower to improve low frequency power handling. The Blue like is the larger cab but tuned to the 'wrong' frequency to show the effect of an 'untuned' cab. You can see they are all the same basic shape. The excursion rises as the frequency falls, then there is a dip in excursion as the port kicks in with the deepest point right on the port tuning frequency. Below the tuning point the excursion rises rapidly reaching dangerous levels at subsonic frequencies. This pattern is shared by all ported cabs. The crucial points are 6mm excursion where the Kappalite starts to distort and 11mm excursion where it starts to destroy itself. You can see that the Kappa in the large box (yellow line)can't handle 450W without distorting even in it's pass range. Eminence themselves recommend 300W as the maximum power. Below 38Hz it will exceed 11mm and be destroyed. You need the bigger box though for a flat frequency response. In the smaller box (pink line) the Kappa gives little or no distortion until the port unloads and stays below the 11mm destruction point until 30Hz. The blue line shows the effect of the wrong (too high) tuning; the 11mm destruction point is reached at about 42Hz which is just about low E. So if you use a Kappalite in a poorly tuned large cab with the full recommended power it will fail. I hope this helps the non techie. All the experts on here already know this. I have some thoughts on what this means about how speakers should be advertised and what it means for customer service, but I want this to be purely factual so I'll stop here.

I'm really pleased it has worked out, that flat clean response takes some getting used to, I really like the Hartke sound but it does clank and it makes all my basses sound a bit 'Hartke' which is good in some situations but not others. What I like about the Beyma is the control over the deep bass, as you say it does bring out the sound of the bass. I find them a lot less boomy on stage too. were you using the Hartke in the kickback position? If so you might be losing the top end because the speaker is no longer pointing at you, the audience might be hearing more than you are. Of course the solution is a second Beyma, You'd better keep those templates.

[quote name='Grangur' timestamp='1380782960' post='2230381'] Please can someone tell me where I'm wrong here? I would have thought the problem causing the pop is a spike in the circuit caused by the switching. So surely what we need is a smoothing capacitor going from the live of the battery to the earth, or maybe across the terminals of the battery. Just another thought, would the pop disappear if you only used switching of one cable - the live, maybe? [/quote] I think you are right about the source of the noise, inserting the jack switches the power on just before making the connection and avoids this. The capacitor the OP refers to is a low value cap designed to reduce sparking in mains switch, or sometimes to remove radio frequency noise on the AC mains.

You are quite sensible to look for a solution. There's a sticky above about volume gain etc. In an ideal world you'd just turn down the bass and turn the amp up but I find the tone and volume interact on the bass and turning the bass right down doesn't improve the hum and noise to signal ratio. Putting something in the fx loop that will reduce gain is a good idea the other is to use a simple pre-amp between the bass and amp, there are plenty of cheap ones that are used to mix guitars. Some DI boxes have a volume control on too.

Actually I think Skidder has a point. About the way these and other speakers are advertised and sold.With all their experience Blue Aran are well aware of the popularity of these drivers as the pre-eminent bass guitar speaker of the moment. For them to say they aren't suitable for low frequencies is disingenuous at least. in any case 'full range' includes these frequencies. These speakers are advertised as handling 450W and 900W music programme by Blue Aran with none of the qualifications which appear on the Eminence website, they are also advertised as being good down to 40hz. There are no notes on their advertising which suggest there are qualifications or conditions to this. Suddenly when there is a problem the amnesia about limitations which clouds their advertising department is swept away and they become Europe's unimpeachable experts. I believe they have a moral duty of care towards their customers. They certainly have a legal one. It is not reasonable to expect every customer to know the intricacies of cone excursion. It is reasonable to think that a speaker advertised as handling 450W at 40Hz can handle exactly that, even though those of us with any technical will know that claim to be false and misleading. I want Blue Aran to succeed, I have been a regular customer and in the past have recommended them. Recently I have found their customer service to be increasingly less helpful and less customer focussed. I hope they are following this and offer some help here. At the very least they need to modify their website to more accurately describe the capabilities of their merchandise.

Play it first, the neck dive is painful, literally as you get very sore after a couple of hours playing pulling it straight. If you can live with it the sound is stunning. You will either love this bass or hate it. It looks and sounds fab but it handles like s**t. Go for the Epi Pro, it is worth the extra over the straight TBird, You get better PUP's and active electronics but more importantly you get a proper TBird neck of laminated wood running right through the body rather than a bolt on neck. This neck gives awesome sustain and the Pups are much better, some say better than the Gibson pups. I've just put my Gibson TBird up for sale, it was fun whilst it lasted but in the end I don't need RSI from holding the thing straight all evening.

Yeah, Yamahas have been busy with the new budget range which kind of relate to the Club series in the way the Mackie Thump does to the SRM450's, a cheaper, less able alternative that trades on the name but sounds OK so long as you don't push them. The DSR's look good on paper but I haven't heard them yet. 12" drivers are really not good for vocals as the polar radiation pattern is usually poor, I'm not surprised you liked the 10's if vocals are important. I really liked the old Mackies with the midrange driver but haven't seen any around for a while. I'm going over to my own designs now, tweaking the Yammy 112's was just an idea I thought I'd try, they do sound better though and feedback rejection is a lot better so if anyone out there is using them .....

I absolutely agree about the PV PA speakers, their horn driver is just not up to the job and I think they use the same driver in all their cabs. There are rumours that the driver has been changed in the more recent cabs, if it is true then it is about time. It's either bonkers or laziness to put such a poor horn in with a great driver like the Black Widow. The Yammy is a strange one, I quite like them, better sounding on vox than some of the JBL's and EV's. The horn driver is a little gem (marked as yamaha but I think it is the Eminence PSD 2002) let down by the bass driver. The upper frequencies are rather nice sounding and the bass at low levels is good but the mids are fairly dreadful. If you look at the plot of the Delta 12A [url="http://www.eminence.com/pdf/Delta_12A.pdf"]http://www.eminence....f/Delta_12A.pdf[/url] you can see why, there's a huge peak of 9dB above 1.5kHz and through the crossover region. Why you would choose this driver when you have the buying power of Yamaha I don't know, excursion is poor too, though not a problem if you keep the bass away or use subs. The crossover is nicely made but they haven't really dealt with that mid hump. Reversing the tweeter is normal practice with 2nd order crossovers. (theirs is 2nd order for bass and 3rd to the horn) it took me 10 mins to try, I wish I'd thought of this a couple of years ago. Spot on about the PA too, it is such an afterthought for too many pub bands.

If you have these PA speakers then you'll know about the bright sound they produce. They really punch vocals through the mix but have a tendency to shouty harshness especially with female vocals and can also cause feedback problems. I rather like them for PA as I like vocals well forward but I tired of the harshness,even though you can eq most of it out. Here's a zero cost fix, reverse the connectors to the tweeter/horn. This reverses the phase of the horn so at the crossover frequency there will be a small dip in the frequency response. The shoutiness (and feedback) is caused by a mid-range peak made worse by the very ordinary Eminence Delta driver they use (I think they have moved away from this in recent models but you'd need to check) which has a sharp midrange peak far too close to the crossover frequency. You'll hear the phase reversal as a veiling in the middle range of female voices and the peak is still there but less noticeable. Overall the sound is a lot more natural and a bit less wearing for the listener. If you prefer the factory sound you can just put the wires back where they were.

sorry i didn't see this earlier. The best joint for a DIY cab is the reinforced butt joint, where you run a 1" sq batten along all the joints as recommended by Fane, Eminence etc. you can screw through the battens which holds everything together whilst the glue dries. It doubles the glue area, lends some mechanical strength through the screws and adds a little bracing to the panels. Plain butt joints lack glue area and I find are prone to failure, finger and dovetail joints are more suitable for a production line and need high skill levels, Rabbet joints make clamping easier but add little strength. This is the main supplier of cabinet corners in the UK [url="http://www.adamhall.com/en/Cabinet_Corners.html"]http://www.adamhall.com/en/Cabinet_Corners.html[/url] click on the pic's for dimensions.

[quote name='Bill Fitzmaurice' timestamp='1380232030' post='2222736'] Many amps incorporate HP filters, it greatly reduces warranty claims on blown drivers. [/quote] Quite right, with the almost wholesale use of ported speakers the only surprising thing is that switchable filters aren't incorporated into all bass amps. They are widespread in PA amps and in mixing desks. We know exactly what happens when you don't have them so missing them out is half-assed engineering on the part of the amp designers. The idea that manufacturers are putting out ported speakers with 3mm xmax drivers and claiming 600W handling, then making amps with 600W outputs down to 20Hz, incorporating 18dB of bass boost and selling them to people with 5 string basses and no technical training seems pretty cynical to me. Probably the triumph of marketing over sound craftsmanship.

Ok the usable frequencies are usually quoted to be the point where the sound drops by 6dB. If your speaker is ported, and most are nowadays, this will also be about the point where the bass port ceases to be effective. Below this point you won't hear much bass but because the cabinet has effectively become just a box with a big hole in it the speaker is free to flap around, the excursion becomes so excessive that the coil will leave the magnet gap and probably start banging against the back of the magnet. This will eventually destroy the speaker depending upon how much you do it. So, the only effect of trying to go below this frequency will be to distort your sound and damage your speaker. Below this point the power handling of your speaker will fall dramatically possibly to only a few tens of watts. Yes you will blow your speakers. The best way to protect them is to use a high pass filter, which will also clean up your sound. You are right to think about cutting out the treble to get a bassier sound rather than trying to boost the bass with speakers that aren't capable of this, the only other way is to use massive power and speakers designed to handle these frequencies.

[quote name='owen' timestamp='1379949295' post='2218591'] I do not want to de-rail this thread, but I am looking for some active PA speakers for work (FE college doing live gigs with bands) and for church (different rigs) and would welcome opinions from those of you who seem to be using them in the wild. Thinking about QSC/Yamaha 12" + Sub offerings. Wondering about the Yamaha 15" but thinking perhaps a 15" + 1" comp driver might not be a happy combination but fancy the bombproofability that the 15" would offer for learning how to use PA systems. I am fully aware that teaching them how to not abuse stuff is part of my job, but you would be amazed at what the dance teacher does to the rig (and her ears) when my back is turned. [/quote] Hi Owen I have both the Yamaha S112 and 115's. On the plus side they have proven to be bomb proof over a long time. The sound is very forward especially the 12's which have a strong midrange peak which brings vocals right to the front of the mix but can make them sound harsh and cause some feedback problems. The 115's are better mannered. I've always liked the sound of the horn drivers Yamaha use but am less keen on the Eminence bass drivers. The latest Yamahas have new drive units, I believe they are manufacturing them in-house but someone else may know more. I host a thread on PA/live sound on another forum [url="http://www.ultimate-guitar.com/forum/showthread.php?p=31527243#post31527243"]http://www.ultimate-guitar.com/forum/showthread.php?p=31527243#post31527243[/url]. Probably better to start a new thread here or to continue there rather than to interleave this into someone else's thread.

There are two coils wound in the opposite direction. only the one next to the string picks up the string movement but they both pick up mains hum and electrical noise. Because they are connected in reverse the current induced by hum and noise are reversed in polarity and cancel out,so only the sounds you want get through.

There's two parts to your question. is this ok as far as the amps and speakers are concerned and how will it sound. You can do this perfectly safely with a solid state amp if your existing cab is 8ohms or 16 ohms and the second cab matches the ohms of your Mark Bass. Two 8 ohm cabs will give you 4 ohms overall and two 16's will give you 8 ohms overall. If you use a valve amp you will have to match the output to the speakers overall impedance. In each case the power handling will be twice the power handling of the weakest cab. If your speaker is 4 ohms it is possible to add a second cab but you will need some special leads or to rewire your cab, if you just plug them in your amp will struggle and may die on you. If you absolutely want to go ahead with 2x 4 ohm cabs then you need to come back to us. As to how it will sound, if you add a second MB cab it will sound the same but louder. If you add anything else you will lose the identity of the MB in the sound and of the other speaker too, the sound sort of blurs together and the only practical way of knowing what you will get is to try it.

Good luck, hope you like the way it sounds.