Phil Starr

Could be a number of things tripping the circuits. They boil down to too much current, earth leaks and a faulty component, anything from the trip itself to absolutely anything connected to the mains including anything in the same building, nothing to do with the band! Might be something like the fridge stat in the kitchens for instance. The most common reason for a trip is an earth problem. Those earth leakage breakers are designed to save you from shock and are really sensitive. The way to avoid tripping these yourselves is to plug everything into a single socket. This also protects you from shocks. The reason is that if there is anything wrong with the house wiring (and those socket testers won't pick up this fault) the earth on different sockets may have different voltages on them. Then if you connect between the backline and the PA by touching a mic stand for instance a small current will flow, 6 thousandths of an amp is enough and off goes the mains, but the lights stay on. Really you shouldn't normally overload a single socket. 13A is 3000W. It will almost certainly be connected to a ring main with a 32A trip. You'll blow the fuse in the plug first. You may have 3000W of amp but unless you are producing 100% distortion every second of the gig you won't be drawing 3000W, that's just for the peaks. Valve amps draw a little more but I doubt that your average power draw for the sound is more than 300W. the only way you will draw 3000W is if you have a lot of old fashioned lighting. Plug that into a different circuit and don't put it where you can touch it to avoid the earth leak problem. It is really important you don't trust the house wiring. Even when recently tested one loose connection can create a problem. Always plug all your gear into a single socket so that all of it is earthed to the same point, if you get a shock off any of your gear something is wrong, it isn't static. Be safe.

HI David, welcome to basschat. I'd strongly advise you against a 'practice' amp for two reasons (at least) proper practice amps are tiny things that just make a noise by and large. They help you practice but are usually only 10-30W and cost under £100 but although very good value ultimately they don't do bass very well and are ultimately unsatisfying. The big plus is that they are small so if you practice in a bedroom they don't take a lot of space. http://www.thomann.de/gb/hartke_b200_bseries_basscombo.htm A combo with 200W of power and something like a single 12 or 15" speaker or a 2x10 built in will enable you to play with a full drum kit in the rehearsal room and even most full venues as a stage amp. They will also make a much nicer noise and that encourages you to practice. (The most important reason to go this way, especially as within reason money is not the main isssue for you) http://www.thomann.de/gb/tc_electronic_bg250_115.htm Then there are the things that most guitar shops sell, usually in the 50-100W range and with a 10-12" speaker. For a bass player they are largely pointless. They aren't loud enough to play with a drummer and guitarist, even though some of them sound pretty good. They are designed for the shop not the player, they hit a price point for the person who wants something a little better than a practice amp, they look like a real bass amp and they will sound incredibly loud in the shop, crucially they don't take up much space in a shop which sells 10 guitar amps for every bass amp they sell. Ultimately they make little sense, too large and loud for normal practice and too small to be used as a practical gigging amp. http://www.thomann.de/gb/hartke_a70_aseries_basscombo.htm So for something flexible that will encourage you to play more often, sound good and get you out of the shed and playing with other people without getting left behind for volume go for a small but decent combo. It'll live with you for at least a couple of years until you are experienced enough to have ideas of your own about your ideal amp.

Don't worry about the impedance of the tweeter, Piezos work in an entirely different way and they have a very high impedance which falls with frequency. They usually have a very high value resistor in series so they make very little impact on the overall impedance. they don't need a crossover and I suspect the crossover here is simply to filter the high frequencies from going to the main driver. Hence the effect when you remove it from the circuit. I suspect this mod is a very good call.

Careful here or you'll end up like a guitard, Having to play at 11 to get your tone Seriously the band sound has to come before the bass sound so try miking the cab or running a DI box off the speaker lead. bands always sound better with low on-stge sound to my ears. The other thing you get when playing loud on stage is lots of feedback/resonance in your strings and this affects your sustain, and the way hammers, pulls and slides sound (probably ought to concede the same to our thin stringed friends here) and this affects the whole way you play. You could try a little compression/extra compression to get this effect too. Try and resist the temptation to go too loud.

That's the weight of one cab! we didn't set out to design a lightweight either. X max is rated more conservatively than the Eminence speakers. The 3012LF isn't really suitable as a single driver for bass as it is designed as a woofer in a two way speaker and has no top end. The 3012HO is the one we considered. The Beyma is less than half the price in the UK. At the moment US speakers are fairly pricey over here. We felt the 3012HO didn't offer any significant advantage over the beyma except for a midrange hump which we thought would sound nice. We'll give details of alternate drivers in the final design. The Beta 12A-2 looks quite promising. Remember we set out to create a 'simple to build' design and i may have said something along the lines of more VW Golf than Lamborghini.

If you really want to rationalise/save carrying stuff I'd think about actives. They are getting better all the time and you'll get great reliability and functionality. You'll get £200 for the IPR1600, less if its the old heavy Peavey amp. (I'm looking for a third IPR1600 if you do sell) RCF, Mackie (not the Thumps) EV, JBL, Wharfedale, HK all worth a look at/listen to. Even the better Behringers are going to sound better than your Peavey but I'd look at other brands. Second Hand you should be able to pick up some bargains if you want passive speakers, everyone is updating their passives to actives because they make life a lot easier for anyone other than techno nerds like me.

The beyma SM212's

OK the latest update. The prototype speakers are now braced with a pair of braces across opposite panels andf rom the rear panel to the cross braces as there isn't anywhere sensible to fix them on the baffle. The cross braces are fixed to vane bracing which also stiffens up each panel. I've inserted some polyester damping between the rear of the speaker and the rear panel. All this adds a couple of Kg to the cabs. The speakers have had a run out at their first gig. Also the first gig with the new band [url="https://www.facebook.com/pages/ReD-band-uk/246798508841316?ref_type=bookmark."]https://www.facebook..._type=bookmark.[/url] Here's what I found. They got me into trouble in the first set. My preference is to keep bass off the stage and DI through the PA but my band like a very forward bass in the mix and lots of bass on stage. That's a silly thing to say to a bassist with a new rig! Initial balance out front is excellent, on stage bass was just far too loud. At the break my drummer complained he couldn't hear his own snare! I think I may have cured him of constantly asking for more bass all the time . Anyway as far as the review goes a pair of these don't lack for volume. One would have easily coped, This was in a 250 people sized space with high ceilings not huge but bigger than most pubs or clubs. If I had to summarise the sound in a word I'd settle on airy. The bass seems limitless (with my 4string Precision, American Deluxe). I know there is a 1dB midbass peak from the WinISD plot but it isn't really noticeable. I always roll the bass of quite steeply at 30Hz but the general feel of the bass is that it is limitless, no real changes as you run down the E string and no compression as you turn up the volume. That 7mm Xmax gives you plenty of reserves at very high sound levels and the frequency response is essentially pretty much flat. These aren't going to give you the 'punch' of an old school 2x15 or 8x10 without some serious signal processing but will give loud undistorted bass. Like I say, they shift a lot of air. The top end is equally airy, The speakers claim a flat response up to 6kHz (-10dB) with only a minor break-up peak at 2kHz and that's pretty much what I heard. It's a bit like the sound you get DI'ing into the PA but rolled off at the top end so you don't get all the noise of fingers on strings, yeah I know, poor technique. That's the point though, without the usual midrange resonance and a bit of extra top end (without the extreme top of a horn) these are quite revealing of what you put in. So pretty predictable really. These are fairly capable speakers for the price with a good clean bass with no bass compression at normal volumes and no real sonic nasties. Not the choice if you want a speaker with a strong character but a good modern voiced unit. One is enough for most situations a pair are seriously impressive. 14.5kg, 350W thermal, 98dB/W and about £150 for a home build including fittings and coverings. You could build one from this thread but I'll do a step to step guide once we finalise on a few details and build the final design. Cheap and cheerful 2x10 to come.

plug the guitar into the tuner and then the tuner into the same input you normally use on your amp. When you switch the tuner off it is true bypass, ie it just connects the input straight through and does nothing to the signal Almost anything will be better than the Peaveys. They never did sort out their horn driver which is a shame as the bass drivers are generally good. What's your budget and what will you use them for?

FWIW Bill is absolutely right, as is LukeFRC. It's possible to make a 15 go down to 20hz and to make one that is 99dB/W but you couldn't do both at the same time. To be efficient you need a light cone and a short voice coil, to be deep you need a heavy cone and a long voice coil. You can get efficiency up by using a huge magnet but at huge cost. Even then you would eventually overdamp the speaker leading to a loss of low end. All speakers tail off in their response at both ends. Bass tails off at about 12dB/octave in a sealed cab and usually 24dB/octave in a ported cab. This means they all produce some output at 20Hz, just that it is too little to be of any use. In any case your bass goes down to 41hz for a 4string and 30ish for a 5 so there is no need for lower. Excursion also doubles for each extra octave so you'd have to halve the power rating if it really did go that low. It's a dishonest claim really 1dB is pretty much the smallest change in volume you can detect, so 0.6db won't be noticed. If you like your sound then only the 2x10 will give you more of it, The 15 will change your sound. You'd have to try it out to find out if you like the change or not.

Sorry, speakers I'm OK with but I'm no expert on any particular bit of DSP. I really can't tell you if one manufacturer has done a good job and another not so much. A couple of observations though. Signal processing is something we've been doing for as long as there has been amplified music. Doing it digitally should be no different to making the same changes with analogue processing other than it should be easier and cheaper. If some analogue gear currently sounds 'better' than digital then this is temporary, the digital processing will get better and cheaper eventually overtaking it. My taste is for as little processing as possible, nothing on my mixing desk ever goes past 2 o'clock, reverb sparing and little or no compression. The thing is with digital that once you have a really fast computer controlling your sound your options are almost unlimited. As many channels of eq as you like, all parametric if you want, filter any frequency you want, let the computer kill feedback or do your eq for you, protect the speakers , apply compression to any channel or split the signal and compress each part differntly etc etc. Now this promises sonic perfection, but if the organic bit operating the knobs (or even the software developer) gets it wrong the opportunities to sound nasty multiply as well. I'm open minded about it really, excited by the possibilities but not yet impressed by the amp/speaker simulations on offer for example. It'll come but I think we aren't quite there so far. I'd love DSP on my PA though. If I was mixing out in the audience I might be able to out compete the DSP (or not) but stuck up on stage with a bass in hand it's pretty difficult to think I could adjust the eq as the room acoustics change because of the audience coming in or kill feedback effectively. Most of us don't have the luxury of a sound engineer so DSP frees us to concentrate on the music.

Thanks for the article, should have remembered that really because there was a long thread on this a while ago. It probably wasn't the best example to choose I think the rest of what I said is about right though. One of the advantages of this DSP approach is that you are far less likely to blow your speakers through over excursion in return for very little signal distortion/loss of sound.

[quote name='Dad3353' timestamp='1403978439' post='2488307'] It mounts up very quickly, as (in theory...), twice the volume needs 10 x the power, so a 50w amp becomes 500w. The next stage up (twice more volume...) would be 5 kW. We see those in PA systems. [/quote] This is right, you can just tell a 1dB rise and really you need 3dB to be able to say that an amp is appreciably louder. That takes twice the power. So going from 75W to 150w doesn't seem like much but going from 200-400W is exactly the same 3dB step. The real reason is (I suspect) that amplifier watts are so much cheaper nowadays, especially allowing for inflation. I've been toying with buying one of the TC amps and the RH750 is only about £100 more than the 450, 30p per watt! We'd have bought 750W amps years ago but they weren't affordable, and we couldn't have lifted them. Modern speakers, by and large are less efficient, trading low bass and excursion for efficiency. They will handle more power though.

Nice

[quote name='Spike Vincent' timestamp='1403254634' post='2481130'] I would be highly dubious of ANY speaker that has a claimed SPL of 118db. [/quote] You may be muddling the max SPL with sensitivity which is the output at one watt. If the figures are accurate then this speaker is 95dB @ 1W and 118 @ 200W although they may be quoting the figure for both speakers together. [quote name='The Admiral' timestamp='1403261026' post='2481221'] I've used a set of these for a couple of street parties and they've been great. http://www.gak.co.uk/en/yamaha-stagepas-300/7920?gclid=CI39oO2giL8CFagewwodZGEAjg They are also a really portable solution for an acoustic gig and they are typical Yamaha quality, so if you were thinking of buying, you could do a lot worse. Not £150, but the current GAK deal is great value, but I'd also suggest, it depends what you are running through them : if it's a young DJ wanting to thump out earth moving drum and bass, then that's a non starter, but for background or even sensible levels for some party music, they will be fine I would think. They also hold their value really well, with a second hand set going, with the bag (which is well worth getting), and stands for £275 recently. Also very compact and fit easily into the back of a hatchback. [/quote] I have one of these setups, they do an excellent job and the midrange and treble will be much cleaner but they are limited in volume and bass. max output is 112dB only

Skytec are well enough known and the same speakers are sold under a whole lot of badges. If you buy the base level own brand speakers from almost anyone they will come from the same factory in china. The standard practice is to quote power as RMS,program and max doubling the power in each case, these are 200W RMS. For this price you get a piezo tweeter and a driver with a tiny magnet and short voice coil. Piezo tweeters work but aren't ever great sounding. The small magnet means low efficiency, no deep bass and a bass hump which sounds really thumpy. The efficiency is raised by the short voice coil but this means excursion is limited so trning the bass or volume up overloads the speaker. The speaker is rated as 118dB which is a lot louder than your hi fi but only enough for an acoustic act in a pub. These things are remarkably good value for money and this is a very cheap price for them. They'll sound Ok so long as you don't turn them up too high and do a job, They are remarkably well built for the price. Just don't expect too much and you'll be pleasantly surprised. I'd happily give you £100 for them after so i can nick the amplifiers to convert my monitors to actives, actually £150 for two 200W plate amps, hmmm. Get your friend to pm me if you do want to sell.

Enlarge the thumbnails for a good insight into what we are all saying. that shallow roll off for the sealed box is almost a mirror image of the standard bass control. 12dB of bass boost at 80hz would give you a pretty flat response, boost the bass by 6db with the sealed cab and that lump at 100Hz will become embarrassing. With a parametric and patience you might be able to eq but it's not going to be something you do between songs shallow roll off and no lumps and bumps are a real bonus. However with this speaker the roll off is from much to high a point, 300Hz right in what I think of as midrange. Applying 12db of bass boost means demanding 16 times the power. If you are running at a conservative 50W then you are going to need 800w from that lightweight head which your little 10 isn't going to be very happy about.. Far better to let the ports do the work with this speaker and get something else if you want a sealed box.

Hi Chris, what are you trying to get out of this and what do you want to preserve? Is it the sound or the look or the authentic original speaker. Taking the driver out will obviously preserve it but the cab won't be original any more and the sound will change. You could take it out temporarily I suppose and returrn the cab to original condition should you wish to sell. Putting any other driver in will change the sound. As you've found out no-one makes a wide range 18 any more and you wouldn't use a box that size with most 18's currently sold. A modern 15 would outperform your 18 in every way except it won't sound like the original. your box would work well with a wide range of 15's and you could fit a second panel (baffle) behind the original to fix the new speaker to without having major surgery on your vintage cab.

Just looked at your speaker, it isn't really ideal for a sealed box as Q=0.31 is really too low for a sealed box design. It's going to roll off from quite high up and sound really thin in any practical sized box.

Bill is right of course but there are some other advantages to a sealed cab. The gradual roll off is easier to eq, especially if your cab is well damped (with Q=0.7 or less). I'm also finding a lot of cleaning up your sound is about avoiding exciting room resonances, ie rolling off the bass. If the cab does this as part of its design then it can be very effective. The problem with the loss of 3-6dB of bass below say 80Hz that you'll get is that you need more power and your speakers can easily end up running out of excursion if you start to eq extra bass. You can improve the 'bassiness' of your sound by rolling of a little treble and maybe adding some upper mids to add a little brightness. Many cheap drivers have this midrange peak anyway so pack, say, eight of these into a sealed box and you solve the excursion problem, roll of the treble, oh wait a minute......

I find the room acoustics are too often the biggest factor in 'nice' bass, sometimes with the right amp to match the room you get a sweet combination and it just sings. then you take the amp somewhere else and the magic dies. I much prefer my J bass to play, and love the depth, but sadly my American Deluxe P bass just does the job better and sounds good with the band. I suspect your usual set up is just overwhelming with bass because of exciting room resonances. It's so frustrating, I love wallowing in the deeps but have to roll it off nearly all the time.

Don't worry too much, it's very likely that you will end up building a cab that is smaller than that needed to get the very best out of this speaker. Building a small cab is going to have two effects, it will raise the lower cutoff for the speaker and may create a bass 'hump' in output around the 100Hz mark. On the plus side too small a cab improves power handling. Before we had T/S we just used to tune the cab to the speakers resonant frequency. You can find this if you have a signal generator (they have these on-line) and a multimeter as the impedance of the speaker rises to a maximum at resonance. Alternatively you can just tune the cab to 40-50Hz and it will probably work, albeit at less than optimum. If you can get the data or find an original cab then all well and good, if not try finding a cab as near as possible in size to the one you remember copy the dimensions and tune it to 40Hz. WinISD will cough up the port dimensions for this. I wouldn't advise this for a new driver but you don't have a lot to lose. Be careful about how much power you put through it and use a bass filter like the thumpinator if you have one and the speaker should be fine.

if you use the same area and length the cab will be tuned to the same frequency. I'm using round ports for prototyping but the finished design will be slot ported to keep the construction as simple as possible.

Hi Luke, you'll have to wait until Stevie comes on for practical experience, I've never used them. I've not noticed chuffing as a problem with restricted port areas in PA sytems or bass speakers so I've given it little thought. However I roll off the lowest frequencies when I play to avoid room resonances and over excursion muddying the sound so I wouldn't expect to notice. It has been a problem in hi fi designs I've listened to though because of the more critical response to distortions in these speakers. The problem we're addressing here is twofold. Because we have chosen a high Xmax/excursion driver there is going to be more air moving through the port than most speakers of this size and the air speed becomes a significant fraction of the speed of sound creating turbulence. This leads to the practical problem. the cabs are small and have modest dimensions. if you increase the port area then the port has to be longer and it meets the back of the cab. You can bend the port but this was meant to be a simple build and a bent port introduces resonance problems. It can also increase the size of the cab. The solution Stevie suggested is to use a flared port. the reduced turbulance means less noise from a smaller port. Its a neat solution but means more expense and sourcing problems for anyone building the cab. What we hope to resolve with the prototypes is what port velocity we are prepared to live with. Mach 0.05 is the generally recognised upper limit (17m/s) but there are discussions between 15 and 20m/s. http://www.hometheatershack.com/forums/diy-subwoofers-general-discussion/24897-port-velocity-goals-aims-what-side-effects-high-port-velocity.html This is a good illustration for the non-technical of the sorts of design compromises involved in any bass cab design. You can build a basic box and it will work, but there are all sorts of tweaks you can make to get a bit more undistorted sound out and problems at extremes of use that you can avoid.

Hi Luke, I've been on holiday and then my computer crashed terminally so I've been off the boil Just to recap and bring everyone up to date I've built two prototypes out of 12mm lightweight ply and have been using them at practice. I've now installed some bracing which has tamed the rather alarming resonances of the panels and tightened up the sound. I quite like the way they sound now. I've agreed with my co conspirators to do some testing before we release a final design. Three issues need to be resolved, the cab tuning, the port area and the wall material. The current cabs are built with four pipe ports that can be blocked off and altered in length to achieve different tuning. basically I proposed a 40Hz tuning which gives us lower excursion at extreme bass and keeps it within the speakers damage limit up to 300W others have been suggesting a 50Hz tuning which gives a touch more bass and power handling above the extremes. we need to see if there is an audible difference and if it makes any difference in actual use. the port area issue is about balancing the avoidance of wind noise against ease of construction. Big ports are quieter but can pose construction problems or we could buy expensive(ish) flared ports. If we can use something small and simple we will, but the best way of seeing how far we can push it is to try out different set ups. At some stage i want to open up the chance to try the speakers to basschatters to feed into the design