Phil Starr

Is that an old Peavey? Yeah if you measure the internal volume of the cab then divide by the number of speakers that should give you the volume you are aiming at. If the original designers knew their stuff. If it's an old 4x10 you can even afford to blow a speaker, and cut up the grille for your new cabs Remember this was a deliberately undersized (for the Beymas) cab to trim the bass response for difficult rooms, it may well be a decent match for your 10's and the 50Hz tuning may be OK too.

I remember turning up my Dad's amp (when they were out) and listening to it with a pillow over my ears to filter out everything but the bass. It took me 40 years to get round to picking up the bass but I always knew it was for me.

It depends upon the speakers entirely. I'm not sure if you are building the big 50l box or the smaller 30l one which is more likely to suit a random 10" speaker. Are they bass speakers or just some generic 10's? The thing is that they will work, in that they will make a noise, you may even quite like the noise. Without getting too technical if the cab is too big to match the speaker you have you might get some nice deep bass but with a gradual roll off and reduced power handling, it's not uncommon to see power handling reduced to 25% of the rating at certain frequencies. If it is too small then you may not get a lot of deep bass but a boom boom upper bass with not a lot of definition. If you just want to have some fun then if you just play at home levels then power handling should be fine and you'll be able to play. I probably wouldn't want to gig with them in a rock band without knowing more about the speakers. Where in between those extremes they'll operate, well that's a gamble. To be fair if it is a bass speaker or a PA speaker they tend to have broadly similar enough characteristics that a moderately sized cab tuned to 50Hz will kinda work, with the reservations on power handling. A rolled up sweater wouldn't work anyway, you'd need something solid like a brick.

Looking good, don't worry if everything is air tight they should work perfectly. I hope you like the way they sound.

Surprised that no-one has spelt it out yet though it's implied. The gig comes first, if you accept a gig then you have to honour it even if the other band comes up with a better gig later on. Once a band accept the gig they are letting all their band mates down if they try to become a no show. Not to mention the band will soon get a reputation too so doubly bad. first gig in the calendar is the one you have to do.

As a system it will do what you want but it might be worth some time auditioning some speakers and deciding what you want. Your folded horn speaker is going to have a very strong characteristic sound all it's own. Losing that might be something you'd miss or an albatross off your back of course. If you like the Mark Bass and you need more volume get another then you know it'll make a sound you like. you could even consider going for an active PA speaker. Basically a PA amp and speaker closely matched in a single box for slightly less than both bought separately. Basically though go for something that sounds the way you want. Looks like you tend to keep stuff so you might as well start with something you like as it'll be there for some time

Essentially you just need to know the cross sectional area.Add the ports together and then calculate the length. pretty much all the programs let you calculate assuming a circular port so you can just work out what diameter port would have the same area as your four triangular ports. WinISD lets you use rectangular ports which makes it even easier. Yes in theory you ought to allow for a different end correction but the change is tuning will be small. the manufacturers figures for speaker specs are rarely spot on so that's all academic. In practice you'll usually find what you have is close enough. I tend to build, check after and then if the tuning is too far out adjust the cab If it is too far out. It rarely is in practice often you are talking less than a cm of port length and a few Hz in tuning

any progress on this?

you rally shouldn't have a problem. Amps and speakers are rated by completely differet techniques so their power ratings bear little relationship. Amps are really simple beasts. They amplify the voltage until they reach the voltage of the power supply and this is their upper limit and the rating of the amp is worked out from there. That's the loudest sound an amp can make Speakers break in two ways, put too much power in and they will overheat and eventually fry. Alternatively put too much bass through them and they will over extend the cone moving the voice coil out of the magnetic field and maybe even banging it against the back of the magnet. Their testing is simple enough, pass a signal through the speaker increasing the power and eventually it burns out. just below that is it's power rating. When you play music however you don't pass a continuously high signal through the speaker. You play a note and it decays before you play the next, sometimes you play the notequietly sometimes louder and sometimes there are breaks. All this means that your average power to the speaker is way less than you think. Your loudest sound might need 100W to be clean but the average power for your speakers will be only 2W, they won't over heat. The main threat is bass over extension. The other way o looking at it is the sound levels. You say you play at modest levels. Well even in a rock band going flat out you won't need to be louder than the drums. You'll usually get something like 99dB/W out of a couple of 12's so 150W will be loud enough to do almost anything other than massive bass boost or drown out the est of the band. In reality your quietish on stage sound means you won't be running at 800W ever. There's no protection against idiots thrashing their gear with no respect for everyone else on stage or their gear but I don't think you need to worry, just be aware. I'll use the car analogy. Your car may rev up to 5000 revs but if you thrash it round Brands Hatch never letting the revs drop below 3000 then it won't last long, drive it normally and you'll probably never get anywhere near 5000 revs and never need to worry about the limits.

Your problem is that almost any speaker you buy will cost more than the amp is worth. In addition I wouldn't be surprised if the speaker concerned isn't a 4 ohm driverto get the full 15W. The cheapest I found was this http://www.bluearan.co.uk/index.php?id=MON103290&browsemode=category

Thanks everyone, I'm just starting to play with a pick after years playing with fingers only. It's news to me that you can balance the sound out with technique only so it'll make sense to build this in from the start.

I'm a bit surprised by your question, what are you doing with this cab? It quotes 101dB/W and the LMII will give 500W into 4ohms. That's 127dB output. you need around 120dB to roughly match a drummer. If you turn that up full then even the strongest drummer with the loudest kit would be drowned in bass. On top of that you absolutely will be damaging your hearing permanently at those sorts of levels. I'm suspecting you work with guitarists who don't have respect for the rest of the band. These are loud speakers and with a decent amp! Secondly to get a step up in volume you need to double the output power. Anything under 1000w and you will barely notice any difference, That's just the laws of physics. Even then it will only be a bit louder and your speakers won't handle that power anyway. Is it you of the audience who can't hear the bass? I'd be looking at my eq first in this case, assuming amp and speakers are working properly. If you are operating with a lot of bass boost then you may be overloading the speakers, hearing distortion and realising you can't turn up further. Alternatively you are using some mid scoop which is great at home or the rehearsal studio but fatal when playing live.

That's what passed as a PA amp back in 1970. FAL were one of many small manufacturers. It will run into 4 ohms. If I had to guess it's probably one of many amps that used 2N3055 output transistors and probably gives about 70w RMS. Beware a lot of these old amps had very poor protection circuits and the output transistors tend to fry when they get too hot or if you short circuit them. Make sure your Jack plugs are properly inserted before you switch on. It gives a decent sound because it is essentially flat response.

Sounds like a dry joint or a faulty connection, fairly common but sometimes difficult to track down. It could also be a phone or both, a common source of noise is that the faulty connection acts as a radio receiver picking up electrical noises. What you do next depends upon your level of knowledge and how much you like fiddling with stuff. You could start by unplugging guitar and leads and seeing if it happens with nothing connected. If it still happens you know it is the amp (make sure there are no phones switched on nearby) Try the amp in another room. If the noise goes it's your guitar leads or maybe the bass itself. Keep swapping stuff until you are certain. Assuming it's the amp set the volume to a reasonable level and try wiggling each control one at a time. obviously each volume or tone control will change the sound but you are listening for the noise getting much worse or going away. If it does the poor connection is inside the potentiometer or pot behind that control. You can then either try cleaning it with switch cleaner (Servisol is what I use) or take it in to be serviced/replaced. It's not a bad idea to clean all the pots, Dirt and wear accumulates so if one pot gives trouble the rest are often not far behind. The next thing to check are the jack sockets. a squirt of servisol and wiggling a plug in and out may fix them. Pay special attention to any fx loops. those have switches built in so the signal gets through when you don't use fx. They corrode over time and that switch connection can cause problems, especially if you never use them. Beyond that you need to delve inside the amp. Beware the voltages can be quite high and the power supply can store considerable power for hours after you unplug everything. DC shocks are more 'interesting' than mains shocks, not to be repeated. Don't open up an amp unless you know at least enough to keep yourself safe. If you aren't sure then you don't have enough knowledge. However if you've managed to narrow down the possibilities you'll often get a better deal from the repair people.

Most 6x10's deliver a fairly distorted sound and don't have a flat frequency response. A lot of relatively cheap drivers in a portable cab means that the speakers are technically underdamped and give an all enveloping warmth at around 120Hz as well as extraordinary efficiency. Modern fashion calls for a flatter, less coloured response. That's not inherent in the technology but that's what you'll find in a lot of commercial offerings, so it's kind of true but not for the reasons most people think. I use 12's, One does most of my gigs, up to a couple of hundred people and it can go as loud as pretty much any drummer. If I take two it can be overwhelmingly loud, I don't like overpowering bass but after a mild argument with one drummer who kept asking me to turn up I did, to cut a long story short at the end of the first set he complained about not being able to hear his own snare drum. So yes they are loud enough and will give you a huge sound but it's likely to be a bit different from what you are used to. Ignore the comments about neo speakers. Neo magnets are more powerful for the same weight as ceramic magnets but they are just magnets. You can use the extra efficiency of neo to make a lighter speaker or a louder one, or one with a longer throw for extra deep bass or even get a little of all three but there's no neo magic, they are still just magnets. In the end you need to listen and judge them on that. Barefaced are making old school sounding cabs with modern drivers using their 10" units, they may be worth having a look at.

I've got the Tube500 just as people say really. The tube doesn't sound much different but I use it on 100% Tube all the time because it sounds better. If it's any help a the last SW bass bash someone was trying all the lightweight heads he could scoop up. all the usual suspects were there and he ended up preferring my MB tube, and it did sound lovely through his big Barefaced cab. It's just what I wanted really, a good sound with everything set flat and it just makes my bass louder and so far 100% reliable.

A single 2x10 will probably be loud enough for 90% of your gigs, so if you buy a 4x10 you'll be carrying a lot of hardware for no reason 90% of the time. For bigger gigs you might want a second cab but all your eq will remain the same, just plug it in and you'll have the same sound but louder. Stacked vertically two of the cabs will place the top speaker at roughly ear level so you will hear it more clearly than a 4x10. Having a vertical line of speakers will spread the mids in a flat wide fan of sound so all your audience will hear the same sort of sound. A traditional 4x10 tends to beam the sound like a guitarist's cab so people off access get less of your sound. I'd repeat though that you ought to go and try some cabs if at all possible, including lifting them of course. Itsmedunc has made some good points, if you are in the north west near the land of 4000 potholes then take up that offer, if you are down anywhere near Somerset I'll lend you an extension cab. There'll probably be a helpful basschatter somewhere near you.

I think that the PA is an issue best dealt with separately. It's much better to go through the PA for all sorts of technical reasons and good PA has come down so much in price it is probably cheaper to have modest backline and good PA than the other way round. However, (can you tell I was a science teacher) I still maintain backline good enough to be able to run without PA support for flexibility. First of all don't worry about the extra 300W. It'll only give you 1dB of extra volume, that's the smallest change in volume a human can detect. Our hearing isn't linear, it's very sensitive to quiet sounds for obvious evolutionary reasons and protected against very loud sounds so we have the maximum range available to us. The downside of that is you need to double power to get a meaningful increase in volume of 3dB. In practice a 200W amp is enough to do almost any gig if you have typical speakers. You could buy a Transit to transport that flatpack home from IKEA but they pretty much always fit in the back of your car. In this case either amp will be more powerful than you strictly need. Choose your speakers on the basis of which ones sound best, then get enough of them to be loud enough is the best advice. Mixing speakers is fine but problematic. The character/timbre of the speakers doesn't come from the bass for the main part but the mids and if you look at speaker frequency plots they usually have plenty of bumps and dips. When you mix them you'll have no idea if those peaks align and emphasise each other or align with a dip and cancel. The combination will sound very different from the speakers on their own, that's if they are equally loud. If they have different efficiencies then one speaker may dominate and the other be little heard rendering it into an expensive stand to sit the other one on. If you own loads of speakers then trying them out with each other is fun and you may hit lucky but it isn't a sensible thing to plan on doing from the start. Two 12's, two 15's, two 2x10's will all be plenty and in reality you'll end up taking one to a lot of gigs on it's own. Don't choose on size though choose on sound.

I get real pleasure at seeing that, and in knowing it is used and loved. Thanks just a quick one Lidl's have a special offer on table saws. 10" 2000W saw for £99. That's a bargain. I've used one of these aluminium topped little table saws for years before upgrading to something more professional. If you are cutting a lot of panels or just slicing up offcuts for bracing a cab then they are way better than a circular saw. Set up carefully they can be very accurate but they are fiddly (I built windows and doors including all the tenons with my old one) and less repeatable than a pro bench saw. Lidl's are also doing corner clamps for £5.99 useful if you are about to build.

Hi Dave, welcome to BC, I'm pleased to see common sense is prevailing, you really don't need a 4x10, 1x15 combination. That sort of set up is very much old tech from the days when amps were costly and speakers of limited ability. The only reason to choose that sort of set up now is if you love the old school sounds or for the look a huge rig brings. All you really need to be able to do is match the drummer for volume. After all if the drums aren't going through the PA then you being much louder than that isn't going to give you a good sound anyway. If you are playing to 50-100 people then you will be more than loud enough. A modern 2x10 or even 1x12 will just about get you there in terms of matching the drums. I too use 1x12's, a single speaker for small venues and two for bigger or trickier venues like a marquee. My amps are both of the 300W into 8ohms 500 into 4ohms varieties. If you are struggling to hear yourself then it may be because of it's positioning. Being on the ground will reinforce the bass but it means the speaker isn't pointing at your ears so you miss a lot of the mid and high frequencies, if you can lean it back at an angle you will hear more. It may be your eq, at home most of us prefer a bass heavy mid scooped sound. Playing live you probably need to roll off the bass and boost the mids so you cut through to the audience, it sounds better that way with a live band too. You don't say which combo you use or whether you like the way it sounds. Someone has already said it but if it is an 8ohm system then adding a matching 2x10 if that is possible will mean your amp will develop it's full power and the extra speakers will double the efficiency giving you an extra 6dB of sound, putting your combo on top of the extension speaker will raise the speakers nearer your ears. You'll be amazed at how much more authoritative that sounds. The sound you have now but bigger. The ohms bit is simple enough, always use speakers of the same impedance, generally go for two 8ohm speakers, 16's won't draw full power from a solid state amp and two 4's are too low a load for most amps. Two 8's in parallel will nearly double the power the amp will give and that will be shared equally between speakers with the same ohms. As Lozz pointed out that's 450W per speaker with the amp you are wanting to use.. Matching amps and speakers isn't an exact science, their wattage ratings are done very differently, but using a 450W amp into a 300W speaker increases the possibility of damaging your speaker by pushing it too hard.

Ha ha, because I rarely get past the 'prototype' stage mine still haven't had the woodscrews replaced with proper T-nuts.

Mine are built with 12mm Baltic birch ply and weigh about 14kg. All I have is a reasonable strap handle and I usually carry one in each hand. I'm a not particularly big 66 year old so a long way from being a superman. The only problem is that they bang against your legs a bit

thanks, They put me on to Electronic Music Services who could get me a new module just over £100 so probably not worth a repair. https://www.electronicmusicservices.co.uk/find-us/

Anyone know how to get hold of Behringer Spares? I've a F1320D floor monitor and the amp is blown. Looks like a conventional Class AB amp with a switch mode supply, no signs of charring but the overload light is flashing slowly which suggests the power supply is OK. Simplest thing might be to replace the amp module but I can't find a European never mind UK supplier. Are these amps used in any other Behringer models? If so I might be able to track down one with a working amp and blown speakers. the amp module is Behringer Q04-AA900-02000

Those figures are interesting, and completely consistent with measurements taken at Glastonbury a few years back. Oh blessed day when bands learn to turn down and let the tech do the work, and protect their hearing.