Phil Starr

There are a number of problems outdoors but the biggest is that there are no walls etc so sound isn't reinforced by reflections and fades away much more quickly. For bass especially the sound is radiated equally all around the speakers and so half of it is lost uselessly behind the stage. I'd look to double your normal power for the tops and quadruple for the bass for the same sized audience, or just accept the bass will be reduced. You'll also find that unless the space is restricted people spread out more so there is a bigger area to cover. On the plus side without reflections feedback is less of a problem. the other thing to look out for is wind noise which can be a real problem if you don't have a sheltered stage area. You really need something to cover your mics to reduce this, usually a foam filter. We've also done outdoor gigs with our usual PA, we worked it harder and we weren't as loud as usual but we could be heard clearly hundreds of yards away so if you can accept less than ideal sound at lower than indoor levels you can still entertain a crowd and people seem to be willing to accept a compromise outdoors. Talking to a hire firm is the best first step then you can give an idea of cost to the people who are paying.

It's going well. If you decide to have the baffle removable, which helps if you decide you need to fiddle around with anything (bracing, stuffing?) after the initial build, then you need a batten to screw it to. Then you run draught proofing foam right round the batten so it is squashed as you screw the baffle down and forms a seal. Now I just want to know how it sounds.

I run S112's with S118 subs unfortunately they are the old Mk IV 118's which are a bit big, though surprisingly not that heavy. I bought them cheap on ebay though I've used the s112V's for years. the newer S118's are smaller. You could certainly get away with a single sub for what you want, and it would sound as good. I don't think you need to worry about sticking to Yamaha either. You haven't mentioned amps but I think active subs make a lot of sense, if i was buying new I'd look in that direction. You could always run with one sub and see if it made sense to add a second matching sub later, however the unexpected advantage I discovered when we started using subs was that they make a lot more stable a stand than a speaker stand is and take up less floor space so surprisingly they are good for small venues even if they aren't good for small cars.

I've gone down the road of using a little combo as monitor and going through the PA. It's very liberating, I'm the first to set up, one trip to the car and no trouble hearing myself. The band sounds better because the whole on-stage volume has fallen and the sound is fully mixed. I use a Hartke Kickback with the bass rolled off a little and then fill out the sound with the tone settings on the PA. Kick back is important as you'll need to have your mon itor pointing at your ears, you could use a stand though. If you really want to keep your insides moving and your trousers flapping you could always go for something like the barefaced Compact to replace your speakers. The ultimate small combo is the AER amp one, Supernaturally loud due to clever electronics. Doubt if you'll find one much under £900 though and people don't often sell them so used is unusual to find.

I use a Hartke Kickback for this sort of gig. It's plenty loud enough and setting the filter knob right gives a mildly successful string bass tone which seems right for what we play.

[quote name='mrtcat' timestamp='1364562600' post='2028195'] Agree to a point bit the advantage of polyurethane isn't really about being waterproof or stronger . It will give an airtight seal without the need for additional sealant. PVA glue rarely gives a true airtight seal even with cnc cut ply as it actually contracts a little as it cures. Even with ported cabs, the smallest air leaks can affect performance. There's nothing wrong with PVA at all but it will need a sealant bead as well. [/quote] I don't suppose 6V6 want's a big debate about glue but I've designed and built cabs, including professionally for years and I'm also a joiner. Make the joint good and put in enough glue to ooze out when you clamp it and it will form a seal. You won't see polyurethane glue in any commercial cabs, some of the American manufacturers may use Aliphatic glues but everyone else uses PVA. Polyurethane fills gaps because it foams, This means it is no more likely to seal air gaps than PVA as the foamed bits will leak so you should still run a sealant bead. My experience is that the foam is weak and will break easily when stressed, though the glue is perfectly strong when compressed in a well made joint. I really strongly doubt that the choice of glue will adversely affect the eventual build but PVA will do a marginally better job, is cheaper and a lot less messy to work with.

PVA should be perfectly adequate for your cab. I've been using it since 1970 with no problems. It is probably used in 99% of commecial cabs. Polyurethane glues are great if you want a waterproof glue but even with handsaw cut butt joints PVA is perfectly good unless you really are ham fisted. Any wood glue is going to be stronger than the wood if properly applied.

[quote name='deepbass5' timestamp='1364147047' post='2022487'] [url="http://www.bluearan.co.uk/index.php?id=ALTSXM112A"]http://www.bluearan....p?id=ALTSXM112A[/url] [/quote] Have you actually used these? The previous Tourmax with the separate horns were good. I tried these out very quickly at PMT in Bristol just by plugging my iPod in but wasn't impressed with the sound. Without trying a mic through them it was hard to assess how they would perform in a live situation to be fair.

this all looks fine to me. Hope it sounds good to you, I can't wait to hear what you think of the result.

If it looks like a capacitor and smells like a capacitor...

I'm a bit of a techie, I've designed and small scale manufactured gear and still repair stuff. First my actual experience with behringer. I've had two EP series PA amps and they have been utterly reliable and are well made, also a Xenyx mixer, which is utterly reliable also. I used XM8500 mic's, the SM58 look alike which sounds slightly better than the SM58 but with slightly worse feedback control and much more handling noise. The mic had to be rewired and I can't tell you how bad the original soldering was. I think to understand Behringer you only have to think what they are trying to do. To make stuff cheap you have to look at costs across the board. Labour costs and electronics are cheap so the boards are often OK. Materials costs are similar if you make them in the UK or China so shaving materials costs is worth doing, slightly flimsier mouldings, cases and crucially connectors can cut costs. Quality control is expensive as you need skilled workers to do this. After sales care is also expensive. Anything with cheap connectors is going to be less reliable and rushing me-too products onto the market can lead to problems. Having said this behringer won't actually want anything unreliable to come out of their factories they will just engineer a compromise which keeps costs down. Components like speakers which have a significant materials cost can't have the costs shaved without affecting the quality, so the speakers are designed to a price. Most of the dissatisfaction seems to be about the products with speakers in. Ultimately the reason I am wary of Behringer because of their after sales. Some of the retailers I talked to have said that the new distributors in the UK don't provide the support out of the guarantee period that other companies do. Because of the method of construction (shared by most electronic stuff these days) repairs are difficult without new boards being available. No worse than say, Apple but something you factor into what you are prepared to pay. Personally I'd rather pay 10-20% more and get a better product but this gap isn't filled by many manufacturers. Behringer represent great value and the reliability isn't as bad as their reputation but you will find the odd bit of horsemeat if you dine at this end of the market.

There should be no problem plugging even a passive bass into the PA. The only problem with going through the PA is that there is usually only a tiny performance space and you often get tucked behind the speakers where it is difficult to hear. I bought a Hartke Kickback 10 (no longer made) for just this job. The notch filter lets you dial in an acoustic like sound and I found little practice amps just don't sound good in most venues. The trick is to be physically unobtrusive so if you do this regularly it is worth looking out for a cheapish small combo. I've never had any negative comments about taking a bass along, generally you find most of the guitarists end up asking you to play along with them.

Oh Good, I'd completely missed out on the 20Hz issue and I didn't want to break it to you, frankly you don't need to go that low for most hi-fi unless you listen to a lot of organ music with 32foot stops. Glad you've sorted your problem. Yet more Kudos to Alex.

Anyone else had problems in this area. I had a crackle on an amp that I bought from a bass chatter, which obscurely was worst every time I played a G! Fortunately the clue to the fault, vibration opening up a dry solder joint. I went in tapping components and homed in on the power supply, sure enough there were a number of poorish looking bits of soldering and it turned out to be the regulator chip which is only supported on the soldered legs and has a too heavy heatsink clipped on, naughty Mr Hartke. Anyway I checked over a tea break and it looks like I am far from the only one http://music-electronics-forum.com/t7354/ so if you have an odd crackle it isn't the valve necessarily or dirty connectors. Anyone else had this problem. The amp however sounds awesome, well done Larry. Oh, the link above will also link you to a circuit diagram if you need it.

If you are going to brace then 15 should be fine. FWIW i use reinforced butt joints. 1" batten along all the joints. This means you can use screws and glue it stiffens the cab a little and you can keep one panel removable. Don't forget to recess the baffle so you can get a grill over the front of the speaker. the cab needs to be airtight so it isn't a bad idea to go round with a mastic gun after the cab is built. The easiest and lightest bracing is broomhandle dowel across opposite panels avoiding the dead centre, which shifts the resonance up an octave without spreading it. Good luck

The tuning depends upon the area of the port and the length, so a round port of 20 sq cm and a shelf port of 20sq cm would need to be the same length for the same tuning. WinISD gives the option of rectangular ports but if your program gives you round ones then calculate the area and away you go. For example a 10cm diameter port has an area of 78.5 sq cm so if your cab were 39.25 cm wide the port would need to be 2cm high.

6.3A at 110V is marginally under 700W. Even class D isn't 100% efficient so your fuse could blow if you run at high power with any distortion effects or a lot of compression. However if you run 'normally' ie less than flat out with a clean input from the bass and without overdone fx then even if you run into limiting from time to time your average power drain is likely to be less than 100W so a slow blow fuse is unlikely to blow. They are heat devices and they will cool in the gaps between notes. They also deteriorate over time so a new fuse is less likely to blow than an old one. If the fuse is easily accessible I think I wouldn't worry about having a 700W fuse in my amp, I'd just carry a box of spares and make sure I replaced the fuse once a year. It's going to be pretty loud after all if your average power is 500W! If it became a problem I'd go for a 10A fuse. Again I wouldn't worry, the fuse only really does anything if there is a real problem with a short circuit or catastrophic breakdown inside the amp, It's there to stop things catching fire really, if your amp is drawing a continuous current of over 6A then there really is something wrong and your amp won't be working anyway. If I was moving to the States permanently I'd check with Markbass and have it converted though.

The shelf port is pretty self explanatory and you'll see it in a lot of commercial cabs so go take a look. The port is the full width of the cab and a few centimetres high. At the bottom of the baffle there is a shelf inside the cab. This traps a body of air just like a circular port. The area of the port and it's depth are part of the design. The advantage is no need to cut any extra holes in the baffle and the use of the full width of the cab usually means a space saving. the disadvantage is tht a shelf fixed in place is hard to change once the glue is dry. It is easier to trim a cardboard tube if you need to change the tuning.

You have an earth problem which makes your amp dangerous, it sounds to me as if an internal earth connection is broken or possibly something inside the amp is touching something it shouldn't. Not getting it fixed and putting up with the noise isn't really an option I'm afraid. It is dangerous and time off work won't come cheap if the worst happens. Actually scrap that the worst thing that could happen is death, an unlikely but possible outcome.

The volume of the cab is 4x that of a single speaker as bremen says. the port however tunes the volume of air in the cab so you need to recalculate. With 4x12" speakers you will be shifting a lot of air and so the port will need to be a decent size or you will get wind noise from the port. You should be able to find an online port calculator easily enough but if it is aproblem give us the volume of your cab and the tuning frequency and someone will give you port dimensions. It might be worth building a shelf port for a speaker like this

[quote name='rednose200' timestamp='1363479152' post='2013304'] Today I'd forget them and go the Eminence route [/quote] If you are talking about the 1980's speakers he may as well go on enjoying them whilst they keep going. As for the modern Fane speakers I think (I was told by someone with connections to Fane) at one time, when they relaunched a few years ago, they came off the same production line as some of the Eminence speakers. Certainly at the time there was a model for model matching of the alpha/beta/delta and some of the horn drivers. the Fanes were quite a bit cheaper so were a good buy. Both companies have moved on and there isn't the overlap any more. Generally though the quality remains similar in the same price range. A lot of Eminence speakers have a fairly dramatic response peak around 1-2kHz due to cone break up. In the Fane sovereign range the breakup is better controlled. (I just meant the breakup is better not necessarily the sound which is down to taste for instruments) If I wanted a touch of brightness for my cabs I'd look at the current Eminence and Celestion bass speakers, if I wanted something more neutral I'd look at the Fanes or the Celestion PA speakers. Of course not all Eminences or Fanes sound alike and you'd have to assess each speaker individually, but I see no reason in principle to go for one manufacturer over another out of these three, quality is very similar.

[quote name='Delberthot' timestamp='1363208450' post='2009942'] Another thing - if the 4x10" as it is now has 2 ports then should the 2x10 only have one? [/quote] The short answer is that it doesn't matter. Basically for a given port area the port just balances the mass of air in the port against the air in the cab. At the resonant frequency this mass of air will vibrate and create a note. Tune this to the frequency where the speaker resonates and the extra output from the port makes up for the loss of output from the speaker. (I've simplified this for clarity, some will say over-simplified) The reason for two ports is that sometimes if you have a big bass output so much air rushes through the port it starts to make a noise you don't want, so you need a bigger port. If that won't fit then two little ports of the same area or a shelf will do the same job. Any change in the speakers or the volume of the cab will mean you need to completely recalculate the ports. If you can get the Thiele/Small data on your drivers it's a 5min job to do this and you can decide what ports you want within reason. The bracing will reduce your internal volume but if you are using dowel not by much. I wouldn't worry excessively about this unless you are going to use a lot of material for bracing. A litre of bracing material in a 50l cab isn't going to throw your port tuning out by too much but 10l of bracing would. It would also make each cab nearly as heavy as a 4x10

My first guitarist, who started me off (so I owe him) got gradually more and more erratic, then we realised he was losing his hearing and was deaf in one ear. Sad for him but it is really hard for a beginner when things go off piste. Good luck with the gig, you've got plenty of time and you can always do the bassists thing of hiding at the back. Give my best to Berkshire, I lived in Reading for 28 years.

Any news of your Beyma yet?

Looks like you are considering spending quite a lot of money and effort on this. I don't know what speakers Ashdown use in the ABM's but the ones in the Mags wouldn't justify this much effort if you are spending £4-500 on an amp and pre-amp. You might want to consider buying better drive units. However if you stick to a fairly normal cab and are prepared to change the ports then you could try out with the Ashdowns and upgrade later. One of the best lightweight bass drive units around at the moment is the 15" Eminence Kappalite 3015, £200, as used in the barefaced compact (I think) I helped another basschat member with a cab based on this and went to hear him. It sounded fabulous. Don't get hung up on 10's the sound you get is much more dependent upon the actual driver than it's diameter which is only one factor of many.