Phil Starr

Great, that's the deal. free advice for telling us how it comes out.

Oh of course you might be able to improve the cab with some judicious stuffing and adding some bracing to the panels, the betas aren't great speakers but they aren't the worst either.

You don't say what your 2x10 is, if it is a home brew then it isn't going to sell for anything much, the drivers would sell for more on their own. If it is a reasonably well known brand then you would probably get enough by selling it for that to be the cheaper route as everyone has said, there are some real bargains to be had used. If it is a reasonably well made home brew and you are determined to tinker anyway then there are better speakers. For £50ea the Beyma SM110 is a bargain, well made, good excursion though you'll have to wait for delivery at the moment as they are imported specially from Spain. For £60ea there are the Fane 10-300 pro's which i've used. Very strong controlled bass but very neutral top end so they lack sparkle. The eminence deltas are £65 here and are a bit better than the Betas but not as good IMO as the Beymas. For £95 you have the Celestion BN10's (neo speakers) and the Eminence basslites are £90. I'd go for the Beymas or the Celestions. So for £100 you can improve your cab and for £200 you could have quite a good cab with modern lightweight drivers. Hmmm I feel a purchase coming on, rather like those Celestions. You'd probably need to re-tune the ports and check the size of the cut out holes. Look to see what you could trade up to used and then decide

There's a lot of compromise in any speaker design and where you end up depends upon opting for a design philosophy as well as doing all the tests and calculations. We haven't debated this in public yet but one of the issues we are looking at is tuning. I want to tune the cab for the lowest excursion at low frequencies, something that will handle low B fundamental at a couple of hundred watts. Stevie wants it tuned higher for maximum power handling. For most people neither of these would be the issue you might expect, I doubt you'd be pushing these speakers to the extremes they would get in testing or be able to hear a difference. The same is true of cab rigidity past a certain point. Bracing of whatever sort follows a decay curve, a little bracing will dramatically improve the sound of a cab, adding an extra brace to an already well braced cab, hardly at all. Sooner or later you will reach a point of diminishing sonic returns at a cost in time, effort and weight. The philosophy behind this cab is to make it easy to build, whilst sounding as good as possible. I'm thinking of a first time builder who wants a practical cab at a better price than an equivalent commercial cab. At the same time there will be no secrets so it is open to anyone to go for a 'better' driver or better bracing if they have the inclination. I hope a lot of you will be very happy with the sound of the basic cab.

I deliberately built the prototype out of thin panel to investigate the panel resonances and then to investigate optimum bracing. the result is truly awesome at the moment. The cabs sound great at low volumes and dreadful once the volume gets high enough to excite the panels, The final versions will probably be 3/4 and I'll then do some comparisons between 1/2" extensively braced and 3/4 with little bracing. Remember this is just a test bed.

[quote name='JTUK' timestamp='1398434635' post='2434098'] Good... proper ports and not those horrible shelve things.. and 18mm Ply and the additional 3.5kgs weight wouldn't worry me either. Just sayin' [/quote] the whole beauty of a project like this is that you are building it and you are in charge. If you want round ports not a shelf then it's an easy substitution, in all probability we will use the same port area so the lengths will be the same. My intention for this design is to make it as easy as possible to build so people will be encouraged to have a go and will then almost certainly be successful. The big advantage of a shelf port is that you can get B&Q to cut everything and all you need to do then is stick it together. We'll give enough details to do round ports too. My cabs will almost certainly be 3/4 ply. we'll also give enough details to adapt cabs for other drivers and to design your own kickback.

OK thanks, misread GK's website. It's probably still worth the OP trying to find out if it is the pre amp or the amp. If it is the pre amp then check the valve, if it is the amp it's probably beyond home fixes. The 550 will have large storage capacitors in it which could make it dangerous to poke around in, even when unplugged. I doubt there is anything user serviceable in the class D power amp which would cause this sound. I've never worked on a GK but no-one else answered so I thought I'd give my penny's worth.

you are probably in the wrong part of the forum, repairs and technical would be better. Which Fusion is it, one with a valve or one without? Really hard to tell but if it was a conventional amp I'd look at biasing or at something overloading. You could try putting a signal into the effects in channel and seeing if the buzz disappears. If it does the power amp is OK. Alternatively you could take a line out into another amp, if the buzz remains it is before the line out and I'd be looking at a valve swap if yours has a valve. In the end you are probably looking at taking it to a tech I'm afraid.

Speaker ready for its first run out. [attachment=161129:1x12 prototypes 006.jpg]

ports cut (from standard downpipe) to try assorted tunings. [attachment=161128:1x12 prototypes 005.jpg]

I think we might have one to try, though I don't have one here. This cab is meant to be full range for bass and the LF has very restricted top end so it wasn't a top choice for this though it models Ok in this box.

Ok they are up and working, though I want to test them extensively before giving out detailed designs. To me they just run down to bottom E with no change in timbre, just an even open sound. The top is pretty neutral sounding too, no obvious sound added by the cab. this is just a 10 min workout though. More to come

[attachment=161098:Beyma SM212.jpg] Speakers about to go in. Spec Sheet http://www.lautsprechershop.de/pdf/beyma/beyma_sm212.pdf chosen because of excellent excursion figures, good damping and good cone break up performance giving useful upper frequencies. Also because they sound good and are cheapish for a quality speaker. Without more testing though we're not ready to recommend them as the final design, that's why we have two cabs, we can swap ports and drivers and do A/B comparisons.

[attachment=161064:1x12 prototypes 001.jpg] Cutting a long story short I've a new band, a list of 30 songs to learn, and fell so far behind with the diary that I decided time was better spent building a speaker. I'll revisit the discussions we had when I get time, for those of you who find it useful. Anyway if I've done this right it should be a pic of the prototype. Four ports because we intend experimenting to see if port noise is an issue and we want to try tunings for maximum power and maximum output down to low B. The final version will probably have a shelf port for ease of construction. As ordered it is proportioned to take a rack amp on one of its sides. The cab is 50 litres plus enough for the ports, bracing and the speaker. The cab is made out of flimsy 12mm ply because we want to investigate panel resonances. This cab is 6.9kg and the speaker is 4.6kg so with bracing and fittings the cab will weigh in at about 12.5 kg. a one handed lift. I'm off to fit the drive units; Beyma SM212's

I'm assuming he will use the same output he feeds into his current amp or that he intends feeding into his class D amp.

Why do you need an amp? All the eq is done and the monitoring is through in ears, so you only need to be louder and only need something with a flat output. Go straight into the PA and the audience should hear what you do through the in ears. If you or the rest of the band need some on-stage bass then use an active PA speaker, possibly a wedge, possibly not, with the flat class D amp you want already built in. Why carry a box, which for the way you are set up is not needed. Decent PA speakers should handle bass as well as a bass speaker and if you have DSP built in then there should be no way of blowing the speaker.

Just to expand upon the complexity that Stevie mentioned. there are several ways in which you can 'blow' a speaker. The wattage is based on the speakers ability to withstand the heating effect of lots of watts, The cab isn't part of this so putting in two 500W speakers would give you a 1000W thermal rating for example. But speakers also blow because they try and move too far and leave the safety of the magnetic gap and/or bang against the back of the magnet. People talk about Xmax or excursion limits. Since the cab alters and damps the movement of the cone and each speaker is different the cone will move more in the 'wrong' cab than one designed specifically for it and will blow at a much lower power than its rated power. You wouldn't just drop a different engine with more horsepower into a car and expect the gearbox etc to work properly without modification and sometimes it just wouldn't fit, or be a sensible mod.

Welcome to Basschat,

First check nothing inside the cab is touching the cones, sometimes wires etc come loose and rattle against the cone. then check the speaker over carefully and look for something coming unglued, either the dust cap in the middle or the corrugated surround, also possible tears. repairs can be done with Copydex for sticking and Copydex and tissue for tear patching. If the speaker coil is rubbing it needs replacement

[quote name='warwickhunt' timestamp='1397115289' post='2420693'] IMHO if your 350w isn't enough to be heard over the band then 'everyone' is likely playing too loud, which in turn means that if you want to continue playing at those volumes then you may need to look at upgrading your PA so that it can handle the job of amplifying the band and your combo can go back to its job of being a monitor for the bass. Just an outsiders view of the 'likely' issues. [/quote] There's more than a grain of truth in this. I use a 2x10 with 300W and never struggle for volume, I've no idea what the Fender sounds like but it should be enough. The problem may be the guitarists, you only need to match the drummer who of course can't turn up. If you match the drums and can't hear then no-one can hear the drums either and you will sound poor whatever you do. Turn down the guitar amps and the band will sound like a band. The other problem may be where the bass amp is pointing. Bass goes everywhere but the mids and tops from you cab are what you need to pick yourself out from the mix, move the cab or yourself so it points at your ears.

I use the same mixer, I take from aux1 and use a jack splitter to feed to two sides of a stereo amp (Peavey IPR1600) if your budget is limited then there are some good classD lightweight amps from Thomann or even Behringer that would do the job for £200 or even less. Conversely I've just tried the Behringer B205 active personal monitors and for vocals they are just the ticket at £139ea you'll need one each though. I'm buying a second one.

Hi Tom, the trouble is you can't trust everything you hear on the internet, even me. The only thing you can really trust is your own ears. If you want to buy your ideal set up the only way is to try it with your own bass and amp, then try the others you are considering and only pay out when you are happy. Listen to advice but treat it with scepticism. It's best not to obsess too much over speaker size, it is important but is only one factor out of many. All things being equal bigger speakers will give you more bass and small speakers more mids and tops but all things are never equal. You can get mid biased, bass light 15's and bass heavy dull sounding 10's but that has led a few people to forget that these are exceptions that prove the rule. It's also true that we don't all agree over what constitutes 'real' bass. The 'real' bass punch of the average 4x10 is due to packing lots of cheap speakers into a too small box. This actually limits deep bass but gives a real mid bass hump of an extra 3dB or so. Packing lots of speakers together causes interference between them so the bassist can't hear the tops so well, which means the bass sounds heavier, it's often just a loss of upper mids. However I'd say many of the big bands I've seen on tour still use 8x10's because they don't have to lift them themselves and they like the sound. 4x10's aren't 'wrong' they are just another option with a few characteristic features and which are currently unfashionable. So I don't know what you mean by bass, do you mean an extended frequency range? capability to produce lots of bass without distorting or just a bias to bass over treble? I also don't know what anyone else means by terms like 'clean' or even 'neutral' So I'd agree with Thodrik don't make your mind up before you try, you liked the sound of the Aguilars so you have to try them somehow, then these are the ones to beat.

Yep, all good advice. I've been running a thread on this on another site if you are interested http://www.ultimate-guitar.com/forum/showthread.php?t=1591207

Just a thought, is that frequency plot with one or two drivers in the cab? My reservation with the Celestions is their relatively high fs.(fo in Peavey speak) if the cab is tuned to 50ish Hz it may need the ports re tuned.

[quote name='Dad3353' timestamp='1396274039' post='2411637'] I'd add that some singers, mostly beginners, don't like to hear themselves in the monitors. The more they're given, the less they'll 'project'. There's a learning curve here, but sometimes it helps, at first at least, to actually [i]reduce [/i]the foldback level, to encourage them to sing up. [/quote] the reverse is true of guitarists, turn the foldback right up and sometimes they'll even turn down