Phil Starr

You won't need more, seriously. I used to take out a full stack but never needed the second cab. I used to use the bottom cab as a stand for the top one without ever plugging it in. Looked great but otherwise pretty stupid. The thing is you are in a band so making everyone else sound good is pretty important. If you are too loud you'll drown out the drummer who will have to play louder and with less feeling/touch/dynamics so now your rhythm section is ****. You are also very loud so you will be picked up by the vocal mics which will be in front of your bass stack, so the vocals are also ****. If you are louder than your drums then the drums will need to go through the PA and be miked up. They never sound quite as good miked as heard acoustically. If you are miking drums then you should DI the bass meaning you should just use the bass amp as your monitor. (did I just rant out loud there?) The point of 2x10's is two fold. Most of the time one cab is enough, and space is an issue at nearly every gig. Adding a second 2x10 gives you the volume of a 4x10 but you can choose when to use it. From a technical point of view 4x10s are rubbish because of the way the speakers interact. They create different path lengths to the listener so they cancel some frequencies and reinforce others and this changes depending upon where you stand. They also beam the sound out in a cone which bypasses the bassist and half the band making the bass inaudible on stage but overwhelming for the audience. Putting two 2x10s up as a line source creates a broad flat fan of sound reducing unwanted reflections off the ceiling and helping the rest of the band and the audience hear the bass at a decent volume. Raising the top speaker to 4-5 feet off the ground brings it to ear height and means the bassist hears the bass clearer than everyone else, wouldn't you prefer that? The worse way of arranging 4 speakers is in an equal sided square. They only did that because amps were so expensive that speakers just had to be loud in the early 70's, hence the 8x10. Oh, finally if an old fashioned 4x10 costs a similar amount to a 2x10 how much do you think they spent on the drivers? The only reason for choosing a 4x10 nowadays is because you like the sound of a certain cab, something no-one has talked about very much. That is a good reason for choosing any cab, the idea of substituting a Marshall with an Ashdown suggests you haven't thought about sound yet, they are very different. 4x10's and 2x15's are really cheap second hand because people are getting rid of them so if cash is tight then by all means go and listen to a few. Please don't buy a new 4x10 though, you can do so much better.

Bill's answer probably says enough but if you want a little more about amp classes written for musicians then have a look at this. I adapted it from an answer to an earlier thread in BC. [url="http://www.ultimate-guitar.com/columns/the_guide_to/a_guide_to_amplifier_classes.html"]http://www.ultimate-guitar.com/columns/the_guide_to/a_guide_to_amplifier_classes.html[/url] cheers

According to my 1966 'How to Build Loudspeaker enclosures' there was a 1950's trend to build in large resonant columns/tubes under the floors of houses which would be coupled to speaker cabinets and excited by certain frequencies. Only for the rich and foolish of course. The idea was that in a time when there was very little bass content certain notes would boom out in a rich and satisfying way which BC'ers will understand. It wasn't hi fi but it was bass. The problem was only certain notes would boom out. Karlson thought by tapering the opening in that pretty way he could make something which would resonate at all the frequencies. He was effectively trying to make a non resonant resonator! Well, you can see the problem here. A quick look at the dimensions will tell you it was far too small to affect the frequencies he was targeting even if it had worked. There were a lot of nutty designs in those days as well as some incredibly innovative ones.

I'm probably not going to give you the advice you hoped for. Why have you chosen this set up? Is it on price, recommendation or sound, possibly for looks or the badge. You say you like Peavey so why not a Peavey? If you are choosing because you've heard them and love the sound then that's great. Always buy the sound you want. If it is recommendation or other reason then you absolutely have to try out the system before you buy and try out rivals at the same price to check. This can take some time but should be fun. I personally wouldn't go for a 4x10 at all. They really are [b]very[/b] heavy and not needed for most gigs, you really aren't going to need to be twice as loud as your drummer. If you do need the extra speaker area then two 2x10's are easier to transport and will sound better stacked vertically and take up less performance area which is good in pubs and clubs. Modern 2x10's will put out as much sound as a 4x10 although they usually need a more powerful amp to do so. Amp watts are cheap nowadays though. The only reason to buy Marshall is the sound, unless this is the main factor look around and get better quality for the price.

The obvious thing to do with this is to run it from a car battery. In other words make a portable battery amp. You'll need to knock out the filter too. The speaker is not going to be useful, they are terribly inefficient compared with one designed to do what is a very different job. You'd probably want to add a pre amp at some stage but decent battery powered amps are fairly rare and quite expensive. Really the value in any project like this is the stuff you learn and the fun you have doing it. Have fun.

Compressed isn't a clear description, Do you mean quiet or that the sound is lacking in other areas? In the end though it won't really matter. Contact Hartke and find out what replacement drivers would cost. Then you have to decide whether to replace the speakers yourself or take the hit price wise and let someone else replace them. So long as you don't advertise the cab as perfect I'm sure someone will take it on at the right price. Don't be tempted to replace the speakers with non Hartke models this will cost you a lot but not add value to the cab.

For keys you need pretty much the full frequency range and a flat response. I'd suggest using PA cabs and unless you already have an amp then use active cabs. They are usually pretty good value for money too. The bass could then use a sansamp or similar. anything more specialized is likely to work out pretty expensive

[quote name='Dandelion' timestamp='1333925722' post='1608444'] I found a pint of this stuff at TKMaxx. Is it any good? [url="http://www.parkerbailey.com/index.cfm?pid=10249"]http://www.parkerbai...x.cfm?pid=10249[/url] [/quote]Yeah I bought some of that, It won't do any harm as it will be easy to clean out. I use Dr Ducks and the bottle I have looks like it will last 20 years so i don't know when I'll get round to the lemon oil. It's good on furniture though.

You only need a single resistor and as it is in series it doesn't matter where it goes. The big resistors are heavy enough to break a soldered connection so use a cable tie to fix it to something convenient, usually one of the tweeters. Make sure the connection between tweeters is + to - . plus to tip minus to earth if you are using a jack socket. + connector to resistor to +tweeter- to +tweeter- to -connector is one way

By and large broken speakers buzz and broken amps crackle, Intermittent faults are often the hardest to find and by sod's law the most common. A crackle can be anything electrical from the mains socket to the smallest component in the amp. Having said that the 'sensitive' tone control has something going wrong so that is prime suspect. The trouble is that the bit that is causing problems is most likely to be the connection between the slider and the carbon track deep inside the pot and you need to get the switch cleaner inside the works to do anything. Modern pots often have few holes to stop dust getting in and causing this problem which makes them difficult to clean. Spraying the outside or just pulling a knob off (ooh-er) won't do any good and you'll need to take the amp out of it's case at least, be aware of the risk of electric shocks here. Another useful trick is to get hold of a can of freezer spray. If you spray one component at a time the freezing and shrinking will either remove the fault or make it dramatically worse and you have your culprit.You might find this helpful [url="http://www.ultimate-guitar.com/columns/gear_maintenance/a_guide_to_fixing_intermittent_faults.html"]http://www.ultimate-guitar.com/columns/gear_maintenance/a_guide_to_fixing_intermittent_faults.html[/url] good luck.

[quote name='guybrush threepwood' timestamp='1333839910' post='1607333'] Sorry to potentially hijack the thread, but I've been thinking about knocking up a cheap tweeter box using piezos, and I'm just wondering about the wiring... I'd wire 2 in series, as my amp is 525W, but I've heard about adding a 20-30 ohm resistor in series to kill any frequencies above 20kHz that could potentially damage the piezo. Does anyone know what power would this resistor need to be? [/quote] The resistor is about protecting the amp rather than the piezo . They present a capacitative load to the amp which makes some of them oscillate and their impedance falls with increasing frequency which some don't cope with either. I use 5watt resistors and haven't lost one yet. Some piezos have the resistor built in. Check with the supplier if you can.

[quote name='xgsjx' timestamp='1333757196' post='1606244'] Have you gigged it yet? That's when you'll find out if it's doing the job. Home volumes (even turned up a bit) are not gonna tell you if you need a 2nd or not. [/quote] [quote name='Mr. Foxen' timestamp='1333757489' post='1606248'] Putting it in a higher place will tell you if you like one of the advantages of a second cab. Might save buying a second cab to find out. [/quote] there you are we're all agreed

If you've only just bought it then live with it for a while. Your cab will sound very different in different rooms depending upon their acoustics. Try it in other rooms. Play with your eq a bit and you might get the sound you want. A 15 is going to have a very directional radiation pattern for mids and highs. If the speaker is on the floor it is probably pointing at your knees and you aren't hearing the sound the way an audience will. Try pointing it at your ears and see what it sounds like then. If after trying everything you still don't like the sound then you might be better of selling and moving on to something new but give your cab a chance to please first.

You could also try one of these [url="http://www.bluearan.co.uk/index.php?id=SKT902490&browsemode=category"]http://www.bluearan.co.uk/index.php?id=SKT902490&browsemode=category[/url] which unusually do have a L/C filter built in. They'll need a horn which you can buy for about £5 but they are standard screw in units. They don't need a series resistor like many piezos and an 8ohm resistor in series will give you a 3dB cut in sensitivity if there is too much fizz. They have the advantage of going a little lower as well.

[quote name='Bill Fitzmaurice' timestamp='1333629354' post='1604514'] It's not that simple. First off you need at least two piezos series wired to withstand the voltage swing, a single unit won't do it. And while piezos are advertised as not needing a crossover that's not actually the case, for professional use they most definitely require filtering, and there are no 'off the shelf' filters for piezos, you must construct one yourself. True many manufacturers do just toss in a single unfiltered piezo, but only because that's the cheapest way, not because it's the right way. The right way to get better high frequency response without tearing into your cabs is the fEarful headcase. [url="http://greenboy.us/fEARful/"]http://greenboy.us/fEARful/[/url] [/quote] "logical advice gets you in a whirl" I wouldn't disagree with the factual basis of anything Bill has said but with his conclusion that it isn't worth making the attempt. Piezo's aren't great, They usually lack sensitivity, their frequency response isn't very flat and crossovers need a lot of knowledge not least because the manufacturers don't give out much/any information so you have to test the things to know things like their capacitance. But and it is a big but they are cheap as chips and you don't need a crossover for them to work. For less than a fiver you can try out a couple and see what it sounds like. They vary but will handle between 20 and about 35V which equates to 50-150W so two in series is a good precaution. If all you want is a bit of tizz then this is a cheap way of getting it, I'd put them in a separate box, no need to spoil your cab. The Ashdown route is going to sound better and Bill is right that if you want to change the sound of your bass markedly then look to a mid-range unit, Though this is going to pose much more in the way of design problems than a couple of piezos.

Essentially speaker rating is about not breaking your speakers and to a lesser extent about avoiding distortion. RMS ratings are about how much electrical power a speaker will take. The more you put in the hotter the speaker will get until eventually it burns out. There are minor fiddles a manufacturer/advertiser can indulge in but essentially it is a test anyone can do and so is easily checked and tends to be a reliable and convenient way of measuring. The only thing is that it only measures one aspect (heat dispersal) and so doesn't relate too well to musical abilities. Most manufacturers also give music/programme ratings and peak ratings. Music is usually double the RMS value and peak 4x. Music isn't continuous so the speaker normally cools down in the quiet bits and you can usually put a lot more power through a speaker for a fraction of a second so these are meant to be a 'real world' figure. However these are only rules of thumb and there is nothing to stop a peak claim of almost any figure, if it is short enough in duration. If they stick to 2x and 4x then it doesn't tell you anything more than the RMS value, unless you don't know your two times table. The main thing you need to know as a bassist however is that there are two other good ways of destroying a speaker or at least making it sound bad. The first is over excursion, pushing the cone beyond its limits. The lower a note is the bigger the excursion and there are plenty of bass speakers that, given a really low note will only handle a tenth of their RMS power. That 300W speaker might be only 100W for a 4 string or 30W with a 5 string. Finally wear and tear will knacker a speaker, run 600W through a 300W speaker night after night and it won't last as long as it will with just 100W through the same unit. Hope this helps

BFM is right, The higher frequencies (those with wavelengths shorter than the diameter of your speaker) are beamed forwards but the lower frequencies are radiated 360 degrees. In a room they are reflected off walls floors and ceilings giving the extra 6dB. To get 6db you need 4x the amplifer power so you are going to notice. On the plus side the lack of reflected sounds means the bass will sound a lot cleaner. As it happens a BFM cab with a horn element would be ideal for use in this situation with higher efficiency and better control of radiation. Increasing the speakers radiating area helps a lot in this situation, outdoors is the only time I use a 'fridge' (actually a 1x15,4x10). Remember that the PA speakers have exactly the same problem so they may not help much unless they too have a spare 6dB. In the end you will probably be OK, people will hear the bass but it might not be so bassy, you might have to turn up full and tweak the eq to get max bass but avoiding overloading the rig. It'll sound different but you'll be fine.

It could be an earth problem or a rf (radio frequency where some of your gear is picking up radio frequency noise and another part is rectifying it and turning it into audio) problem. Just about every electrical device emits small amounts of rf noise and we are surrounded by a sea of (usually) invisible radio noise. Without hearing it, and sometimes even then, it can be difficult to diagnose. Since you have changed the amp it may just be that, your fx may have been picking up or radiating rf before but this amp picks it up and the previous one didn't. It may even be that the rf source is nothing to do with your rig but the new rig is receiving those frequencies and the old one didn't. Do you still get the same noise in other rooms/buildings? Work logically. Run everything off batteries if the noise goes then it will be the power supplies. It could be an earth problem or one of them radiating rf. Try using only one fx at a time. You may find the culprit that way but it could be an interaction between a combination of two or three of them. If that doesn't find the problem then connect them all up and remove one at a time. Reconnect each and remove the next link in the fx chain. If you find the fault then don't forget it might be the box but it could be a connection in the lead to that box. If it only occurs when everything is plugged in then it might be one fx is causing another to go unstable and oscillate. You do have a lot of fx. chaining them in a different order sometimes cures the problem. Remember it may not be the new amp. Just because you bought an amp it doesn't necessarily mean your other stuff didn't break that night. The amp may just be more sensitive to noise or it may be radiating rf which is being picked up by one of the fx. Good Luck.

[quote name='Bill Fitzmaurice' timestamp='1332505729' post='1589245'] The center of the panel is the most important bracing point, as it's where the panel is subject to the greatest flexion. The cabinet should be fully lined to absorb all internal reflections. BTW, greenboys text is very well done, and I might add that it reads better than my Omni cab plans that was the original source. That would be the same cab that I built in both spline and cross braced versions to confirm by measurement which bracing scheme worked better, and by how great a margin. [/quote] Do you still have the data? It would be genuinely interesting to see what you came up with. Actually I agree with you about cross bracing being the way to go. Its not that vanes won't work but they work best if critically applied and the big minus, you need an awful lot of vanes to really stiffen up a cab and that can add a lot of weight. On the other hand we don't know the dimensions of this cab or the dimensions of the speakers themselves, there may not be convenient places to place cross bracing. You are wrong about the placing of the brace in the geometric centre of two panels of equal size and mass. We are talking about resonance and not simple mechanical strength here. the aim is to stop unwanted sound being radiated by the panel and a brace in the centre is going to be as effective as trying to damp a bass string with a finger directly over the twelfth fret.

[quote name='Dave Tipping' timestamp='1332425286' post='1588147'] No. It's light as hell thanks to (neo speaker ..and minimal bracing ), sounds good, goes more than loud enough and was cheap. Cheers for all the comments above .. I'm def. gonna stick some internal bracing in and line it with dampening .. as I said if it doesn't make a difference I've wasted a couple of hours and very little dosh, if it does then great! [/quote]That's great, I think you'll definitely hear a difference in the sound with some bracing and it will probably be an improvement. look to brace the biggest panels first and don't put anything in the middle of the panels as it will simply shift the resonance up an octave. Anything off centre is better. If you pump music through the speaker at a decent volume then you can usually feel where the resonance is greatest with your finger tips, aim to damp those points first. I'm not a fan of wadding in a reflex/ported cab if I do anything at all it is usually just behind the speaker to cut reflections off the rear panel and dampen any standing waves. good luck.

[quote name='chris_b' timestamp='1332326856' post='1586579'] It seems there is more than one way to effectively brace a cab.... [url="http://greenboy.us/fEARful/bracing.htm"]http://greenboy.us/fEARful/bracing.htm[/url] [/quote] [quote name='Bill Fitzmaurice' timestamp='1332334930' post='1586784'] I once used those methods, but stopped after I actually built two versions of the same cab, one using spline, one using cross bracing, measured the results, and found cross bracing to be far superior. ... [/quote] Hardly a scientific test. We don't know what the problems were that you were trying to ameliorate with the bracing. You'd need a lot more evidence than this to say (as you have) that in all cases cross bracing is more appropriate than spline bracing. It may be better in many cases and it is often simple to install and lighter in weight than extensive splines. Chris-b is more accurate and more helpful. The OP can try either or both forms of bracing. Your statement that rigidity is more important then raising the resonance is also false because again it is absolute. You apply it by implication to every cab ever built. If you had simply said that in your opinion rigidity is usually more important I don't think I'd disagree.

[quote name='Bill Fitzmaurice' timestamp='1332340791' post='1586926'] There are. A civil engineer would be quite comfortable with the bracing aspect, while advanced speaker modeling software can accurately predict the effects of various thicknesses of damping materials based on their index of resistivity. [/quote] You didn't read this. "There isn't a single model" "There are" which is plural. My point is that whilst there are good models for calculating the frequency response of a speaker box there isn't a simple model for feeding all the complex parameters to do with sound transmission across the boundaries of the box which is available to automatically do the sort of optimisation that is routinely done with box design. If you know of one then I'd be glad to hear of it. Whilst it is quite possible to calculate the effects of single braces on the forces acting on and movements of individual panels to calculate the overall effects of multiple bracing on all six panels would be beyond any practical utility. I very much doubt that you have performed these calculations on the bracing of your own designs. I expect you do what most of us do and use your experience to position your braces where you believe they will probably be most effective.

You will wish you had never asked. the problem is that there isn't a single mathematical model that will predict the total effects of either damping or bracing. The way any panel resonates will depend upon it's dimensions, its density and how flexible it is. Much of this is frequency dependent and so something which will reduce some resonances will actually make others worse. Cross bracing will stiffen panels and will effectively double the mass of the panel. At most frequencies the pressure changes in the cab will tend to move the panels in the opposite directions so the damping will be excellent. At some frequencies two identical panels will resonate and you could conceivably get some coupling between them, you would avoid just sticking a brace straight across the middle of two panels. The practical problem of cross bracing is that in some cabs finding convenient points to fix braces can be problematic. Vaned ribbing will also increase the stiffness of a panel and to an extent its mass. I wouldn't fix them parallel to each other though as although it looks neat it can create a new resonant panel between the vanes. I don't think anyone giving you categorical advice is helping much, after all using cross braces doesn't stop you also adding some stiffening ribs to other panels. Both will help. Your original speakers will have been built to a budget. Stiffening the panels will help reduce resonances and tighten up the sound. You don't have a lot to lose if you fix them so they can be moved/removed whilst you play around. Of course some of the resonances may be what gives your speaker it's 'character' and removing this distortion may not be something you like.the sound of. These are instrument speakers not hi-fi or PA cabs. Now stuffing and damping panels, that's really controversial.

[quote name='paddy109' timestamp='1332085148' post='1582935'] We all played like complete muppets mind you - hey it's only rock n roll! Paddy [/quote] especially the drummer?

There's something slightly odd about the specs here. That really is quite a heavy cone and likely to be quite stiff as a result so you would expect the frequency range to be more restricted than 5.8k. You'd also expect fs to be lower. I don't think efficiency is particularly low, we don't know how it was measured and a lot of the higher figures other manufacturers publish are generated by 'favourable' testing procedures. (It may be OK, we just don't know.) A lot of Eminence figures are bumped up by quite big mid-range frequency humps for example. You'll get an extra 6dB by having a 2x10 and 100dB per watt is good. On the plus side excursion (Xmax) looks good and Q of 0.34 is pretty near perfect for engineering a flat response in the bottom octaves without too sharp a roll off. I quite like using PA drivers in bass cabs as I prefer the more 'polite' sound you get. You aren't happy with your current PA monitor though so maybe your taste is for something less accurate but more lively sounding. The big problem with building your own is that you can't test the sound until after you have built.