Phil Starr

Just a thought, some time ago I helped fatgoogle who is a regular contributor to basschat design a cab with one of these speakers which was about 150 litres if my memory is any good. It might be worth while asking what his experience was using this cab. Your cab isn't an old Peavey is it?

You'll get 450w into each speaker, but only if you run flat out all the time in practice you won't turn it up full because that will drown out the rest of the band and deafen you and because you have gaps between your notes and you won't play every note flat out. The chances are that if your very loudest point of the loudest note is 900W then your average power will be below 90W and your speakers will be fine.

Don't go for the LF, it is for PA use and is designed for use with a horn speaker. There is something wrong with the Xmax figures since both the 15 and the 15 pro have the same coil in the same magnet. X max for the 15 should be at least 4mm and unless they have done something clever with the magnet geometry which I doubt the Xmax should be identical for both speakers. They used to be identical speakers but the pro had a cast chassis, The pro now has a lighter cone hence the changes in fs Vas and Q. To be honest I suspect tht the figures they give may have other inaccuracies so it will take a while to enter them into winisd and check, I'll do it later if no-one else gets there first. I suspect the sound of these will be little different, the big advantage of a cast chassis on the pro is a slight improvement in heat dispersal and potentially a longer lasting speaker as the chassis is more rigid. Expect to pay about £30 extra for this.

It was just the drive unit in the loft, a spare I picked up when I was using a MarkIV with a 2x15. I picked up an empty cab on fleabay and put the two together. I need to clear out, I can't afford to fall in love with this thing. The empty cab is heavier than my current 1x15. Oh, it sounds nice though, It would just sit in the mix so well.

Just restored an old Peavey 1x15 cab with an old Black Widow driver I had in the loft. Well you have to try it out don't you? What a blast, no top to speak of and a bass best described as 'warm' It just sounded great with the P pup's and some nice bright strings. Pure bass honey. So wrong but so right.

There's nothing to lose by trying the practice amp with the bass turned down with your regular cab. It's not how it will sound in the cab though. The practice amp may be lending it's own tone and you will be using the volume control to balance the speakers. The next stage will be to try the speaker only connected in parallel to your 15. If you get a reversible electrolytic of about 10-20 microfarads and connect it in series this will filter out most of the bass and act as a simple crossover (actually a high pass filter). if you are still encouraged then you could go on to look at a better small speaker to partner your 15 and a proper crossover. The small 'tweeter' will need to be in its own sealed box built as small as practicable inside your main cab. If you like fiddling this will give you no end of fun, it might even improve your sound and you'll learn loads. If you just want a good sound and don't have this sort of curiosity then there's better ways. Me, I'd fiddle. Have fun.

Hey I don't want to get into a big one on this, or get all preachy, I'm as big an idiot as the next person when it comes to my own health and safety but these are public forums and the advice we give is read by hundreds of people so when safety is involved we should be at least factually accurate. I'd hate to think of a fellow BC'er coming to harm through poor advice. Sod it, I'm preaching [quote name='flyfisher' timestamp='1354536188' post='1887005'] Nor would I, but the 'right fuse' will already be present inside the amp because the manufacturer cannot rely on what lay-people put in an external mains lead and, as already discussed, it's quite legitimate for a non-fused mains lead to be used in some countries, so clearly a fuse in the mains lead is not an all-important safety consideration. On that basis, it's quite legitimate for a 13 amp mains lead to be fitted with a 13A fuse, whatever the type of equipment it's plugged into (appliances with a fixed mains cable are a different case). [b]You can't assume the person before you put the right fuse in, the European sockets you refer to are all fused by law but the fuse for each separate circuit is back in the fuse box, they don't use ring mains.[/b] Yes, but how many people get secondhand gear fully checked by a qualified person before using it? Even PAT testing is mostly about earth leakage type testing and certainly won't tell you if the internal fuse has been replaced with a bolt or if the circuitry has been modified. But, again, a fuse in the mains plug doesn't magically make things much safer - or are you suggesting that all our European and American members are at greater risk than UK members? [b]Well their mains is 115 volts lower than ours and all the sockets are fused anyway, if the socket is fused you don't need the plug to be fused as well.[/b] My experience is that mains leads have a habit of finding their way into a big box and people just grab them as needed while putting everything together. This is fine if all the (13amp) leads are (correctly) fitted with 13A fuses but if you have a mixture of 3A, 5A and 13A fused leads then it'll be quite common for the 'wrong' lead to be fitted to the 'wrong' piece of gear and fuses will inevitably blow. What's more, they may not blow immediately because of the way fuses work. Thus, for example, a PA amp with 5A fused mains lead may work fine during a short sound check (depending on its power of course), but if the full-on power consumption is slightly over the mains plug fuse rating then the fuse could blow some minutes into the first set. [/quote] You're right about mixing leads up but very little of our gear uses more than 5 amps even a 1000W PA amp only runs at a fraction of its power (technically if you are running flat out with a 20dB dynamic range then you'll only be pushing 50W a side at about 85% efficiency or 120W, roughly 0.5A so you won't be blowing fuses unless something is wrong) So I know I could bore for England on this but I worked as an electrician for years and in electronics for longer and you don't tell people to use the wrong fuses and expect that there will be no consequences, sooner or later even though the risk is low someone who takes your advice will get hurt. Most accidents happen because of a chain of minor events lead to a catastrophic finale not because of a single large error. Using the right fuse won't protect everyone all of the time and adding one link in the safety chain won't save everyone from electric shock forever but using the right fuse is boringly sensible and telling people not to bother actually opens you up to the distant possibility of criminal liability, should someone take your advice and get hurt. Why would you want someone to take a risk however small.

Personally I wouldn't skip using the right fuse, they are so cheap apart from anything else that you can afford to have boixes of the things. If the fuse in the plug blows first then it can save you the problem of finding an internal blown fuse or replacing a much harder to source fuse on the back of your gear. You are not always so lucky but it can help. If two fuses blow in succession you have a genuine problem which needs sorting. Gear without the right fuse is less safe, Given the amount of gear from the seventies still about and the mods that people carry out over the years you have no guarantee that a lot of gear is wired to modern standards and is safe without a fuse. Think of it as a strand in a rope. The rope might hold with a strand or two broken but you wouldn't trust your weight to it if you knew a strand was cut. Use the smallest fuse possible, as a rule use 1A for every 200W of power, so for anything below 500W use a 3A fuse and a 5A fuse for 1000W with 13A for anything over 1000W . Other values can be harder to track down at DIY/hardware shops.

The radiation of bass frequencies is more or less omnidirectional until the frequency is such that the wavelength is the same as the diameter of the speaker. Multiple speakers behave like a bigger speaker so think of a 4x10 as being like a 20" speaker in theis respect. Being omnidirectional is only about direction though. The sound still gets quieter the further you are from the speaker, It drops off at 6dB as you double your distance from the speaker. With the speakers either side of the stage the sound will be much louder from the nearest speaker than the further one If you were in the front row, you could be 1m from one speaker and 10m from the other. Further out you will hear sound from both speakers. If both speakers are together on the left of the stage then someone sitting in the front will hear more bass if they are sitting that side than they will on the right. Further back it will make less difference ans right at the back most of the bass you hear will be reflected off walls ceilings and floors. I guess this mainly happens when your bass goes through the PA rather than coming directly from a bass stack or whatever. You won't get any difference in total sound produced though.

I'd definitely go for an old 'fridge' type cab, a 2x15 or 8x10 (or 2 4x10's) as they are really cheap second hand and the biggest downside is moving the things, The upside is they are loud so using just 50W is still going to be enough for most situations. If they are just going to sit in a practice room then there is no problem. You may need to rewire to get the impedance right. Something like the Peavey 2x15 which sounds great is 4 ohms as the two 8ohm speakers are in parallel but wiring them in series will make the cab 16 ohms. You are going to get an old school sound, you asked about the advantages of a new solid state amp then it will be more versatile and you have an infinity of choices depending upon your budget. I'd go for a fridge which you can sell on with little or no loss if you decide you don't like the sound. Or build a cab if you have the inclination, it is really rewarding. Don't buy tubes, you can use plastic pipe or thick cardboard tube of the right diameter, try carpet warehouses for the old cardboard tubes they are throwing out.

I've recently gone over to going through the PA and using a small combo for monitoring. Even the guitards have turned down so we now have a lot less to be picked up by the vocal mics. I use a Hartke kickback 10 (discontinued but they still do the 12) which is good because (a) it's a kickback so the sound goes straight to you (b ) it is fairly punchy with not a lot of deep bass so you get the frequencies you need for monitoring. I shove it behind the drummer who loves it because he gets what he needs. Temperamentally I would rather hear what the rest of the band are playing rather than my own tone so the set up suits me. I think the audience get a better sound too.

Oh the exception to this is the compression drivers on high frequency horns. These have a low thermal power rating usually 20-50W and are often built into 3-400W speaker systems and driven by 300W amps. Distortion is effectively extra high power energy and so burnt out compression drivers aren't unusual. Driving a 20W driver with a 300W amp in the expectation that only 10% of the sound is high frequency doesn't always work.

Please will people stop repeating the myth that low power amps are more likely to damage speakers than high power ones. It has no basis in fact or any scientific justification. If a 500W speaker is driven by a 100W amp there is no way it can be blown by the electrical power. If a 500W speaker is driven by a 500W amp it is only under rare conditions that it can be blown by the electrical power alone. If a 500W speaker is driven by a 2000W amp it would be relatively easy to blow with electrical power, Though not easy if you actually played undistorted music through it. Even the Xmax thing is a bit of a red herring. Speakers coils don't leave the magnet gap at Xmax, they just leave the linear bit of the magnetic field into the less linear bit. At the limits of their movement prudent designers will restrict the free movement of the cone so that it will return correctly to its resting position. It will distort, make a nasty noise if it hits the back of the magnet, it won't give you any extra useful sound but by and large it won't break unless you go on doing it for a long time and depending upon the design sometimes not even then. Speakers mainly break through wear and tear, sometimes through manufacturing faults and very rarely through burning out or over excursion. The myth about lower power amps damaging speakers started in the 60's when amplified music first hit the mainstream. The speakers of the day were unsuitable for the high power involved and weren't rated for instrument use. Coils were wound on paper formers and ordinary household adhesives used to stick them in place. The heat form the coils soon melted the glues and distorted the paper formers so the coils shorted against the magnet and the current increased burning the coils out. Amps can give 1.414 (the square root of two) times their rating in electrical power if their power supply is up to it with the extra 0.414 being distortion. Guitarists introduced very high levels of distortion at the time by overdriving their amps at full power which did blow the speakers of the time. Bassists didn't do this anyway. I'll repeat, the main causes of speaker failure are wear and tear and manufacturing faults. Obviously the more often you play it and the harder you push it the quicker it will fail but a sudden catastrophic failure of a new speaker due to the amp being too big or Xmax being too small is rare to vanishing. I hate it when something said in one forum or said by a salesman in a shop gets repeated as well meaning advice on the internet.

There's really two ways of achieving a sound, the rational, working towards a goal, grappling with the science method and the suck it and see "man that's immense" method. Most of us of course are somewhere in the middle of these two extremes. This is the rig of the suck it and see brigade. Two dozen pedals and actually multiple pre amps (sansamp on the floor), this isn't created by any logical process, this guy just plays through boxes, likes the sound and adds it to his rig. His tech will sort out any problems.

Sigh You know you have two options don't you. Buy earplugs and let them get on with it. Become the grit in the oyster until you get some compromise. The trouble is they have too much invested in their Marshall stacks both emotionally and financially to change easily. They've dreamed since they were little boys about standing in front of these things with their guitars singing and this is living the dream.

Thanks for the answers. It's a real shame, I used to build speakers as a one man business so I sympathize but customer service is pretty important too. If I can't contact you then i can't place an order and i can have no confidence about what might happen if something goes wrong. thanks for the tips though, I hadn't come across Armstrong before. Any other suggestions?

People here have spoken very highly of Wizard. I want a set of PJ pups and could do with some advice so I've rung them, three times, and also emailed. They never answer their phones and no-one has got back to me. I'm now reluctant to place an order with someone who doesn't answer their phones or emails as how would I contact them if there are problems. I'd far rather place an order with a small British company particularly if their pup's are as good as people say but is this a general problem or have I just been unlucky?

Your amp's rating is the maximum power it will give without distorting. Try turning it up high and play a really loud note and listen. If you can watch the speaker cone. The first snap on the string will make the cone jump forwards and the sound will be really loud. This dies away quite quickly but the sound continues quieter and quieter for a long time depending upon your actual bass. The amp and speaker are only dealing with full power for a few thousandths of a second, the first hit of the pick or your finger. The average power to the speakers is a lot less than the maximum power the amp can produce. Two things will break your speaker. Depending upon the design of the actual speaker units the first impact sounds may push the speaker cone too far and it will hammer against the back of the magnet making a loud 'farting' sound or worse still it will go out of the front of the magnet. Good speakers will be designed to prevent this but you can break speakers this way. This isn't in the speakers power rating because it depends upon the detailed design of the cab it is in. The second way is caused by all the electrical power from your amp heating up the tiny coil of thin wire at the heart of your speaker. The wattage rating of your speaker is actually the amount of heat it can dissipate before it gets hot enough to start damaging things. Speaker components can get as hot as an old fashioned light bulb. Because the important thing is the average power and your sound rapidly decays as you have heard and because of the gaps in the music you can generally reckon a 500W amp flat out but without distortion is probably averaging less than 50W. Usually it will be even lower than this. A 500W amp averaging 50W isn't going to blow a 100W speaker by overheating never mind a 400W speaker unless you are doing something else unusual. It might 'pop' the 100W speaker but it isn't going to threaten the 400W speaker in all probability. In any case using this system turned up full will drown out the drums and damage the hearing of anyone standing too close. So long as you don't turn up loud enough to make 'farting' noises or any other unusual sounds and you don't use stupid amounts of distortion/compression or bass boost this combination should go on working for years.

Crackling is likely to come from damaged pots or connectors, poorly soldered joints or cracks in the circuit boards or from the breakdown of components with electrolytic capacitors going first usually but not always. there are safety issues and you would need to check the power supply caps are discharged before fiddling around inside the amp. there are several thousand connections inside the amp and resoldering all of them is more likely to end up with you creating other problems especially if there are surface mounted components. You will need a specialist soldering iron with a very fine tip and thermostatic temperature control. You can often find the fault using a freezer spray but even this is a moderately skilled job, if you can read a circuit diagram and can solder then fine but if not you will probably struggle. It depends upon you, if you are happy to spend long evenings learning loads of new skills then what have you got to lose, if you want an amp that works then you will have to pay someone who has spent the long evenings learning this stuff.

This is all getting a bit unreal. When I used to make speakers I paid rent on a workshop, paid bills, bought machine tools etc etc. There's labour costs including the fact that only a fraction of your time is spent making speakers, You have to factor in design time, marketing effort, paperwork dealing with customers etc.etc. You don't go to a good restaurant and expect to pay for just the ingredients, you know that a team of highly skilled people have spent all day prepping ingredients to serve a couple of hundred meals and that the posh surroundings don't come cheap. there's probably nothing to cooking the meal that you couldn't do at home. It would just be a lifetime's training to reach the skill level needed. You probably could build a cab like the Barefaced for £75 but calculate how long it takes and add in the labour costs (what do you pay your plumber or to get your car fixed) and you'll realise there isn't a lot of profit in that £450. You'll need to sell a lot of speakers to make a living.

I'd forgotten this thread. First of all yes i would definitely port the cab. Your amp will overload the 125's but this is more due to over excursion than the thermal load. Having said that they suit your cab a little better. In practice it depends upon how you use them. I've used two with a 600W amp but I tend to leave the bass flat or even cut a little and I don't play in a very loud band. I can drown out the drummer and so it is plenty loud enough for me. If you use a lot of bass boost or are heavy on the volume there is a small risk. How easy would it be to get replacements? If you wnt to be idiot proof the 300's take you well beyond the thermal limits and with the extra air in your cab the speakers are less likely to go beyond the excursion limits. They are going to have an extended bass with a slow roll off in this cab so they might be a bit 'polite' sounding though the bass will be clean and deep. If it helps I've been gigging a lot with the 300's in a 2x10 but I'm swapping them out for the 125's to get a little more character. The 300's are cleaner and will be going into a pair of wedges.

Hi Lawrence, the difference in Xmax isn't that great with the different measuring techniques, I've been developing some cabs for 15" deltalites with 4.2mm Xmax and with some cabs I'm getting excursion limiting at 35W at some frequencies. I'm kind of with BFM on this one, With only two 10" speakers Xmax of 2mm is a potential problem, even if it is 2,6mm in real money. The high resonance is also an issue, though not necessarily a deal breaker. If Fs is 73 then in a cab it will be higher, probably a whole octave over E or more. There will be a hump between 100-150Hz somewhere to compensate but this will give the speaker that sound which so many commercial cabs have. If what you want is that particular colour to your sound then it isn't a problem, in many ways it is the old-school sound. If the OP wants that sound then great but he should know what he will get with the Celestions when there are other more neutral speakers at that price point. That Sica is awful though.

On mine there's a speaker jack deep inside the back next to the power socket which connects the internal speaker to the amp. You could unplug this and plug into any speaker of 4ohms or higher. If you used a Hartke 4x10 with the same speakers in it you should get an extra 6dB using the same power from the amp, equivalent to turning up 2 or three notches. I'd only really do this if I was going to upgrade anyway or if I was able to borrow a spare speaker from someone. If you were looking to upgrade anyway you could buy a cab first and just use the Hartke as a head until you had the funds to buy what you wanted. But, yes I'd look to either buy a bigger amp for gigging or decide I was going to go through the PA, the Harke will do fine as a stage monitor if you really like the sound but it needs some PA backup.

Don't go for the 100W Celestion it has a smaller magnet and isn't really going to be suitable for your cab. Do you have to have an 8 ohm cab? A 4ohm cab means you can use 8ohm drive units and there is a wider choice available for you. I cant find that exact model on Celestions web site. the BL200X (8ohms) gives an Xmax of 4mm but at a lower sensitivity than you give. It may be worth contacting Ashdown and finding out what they would charge for repalcement speakers. Rumour is that they are not too expensive and you would get the sound of the new speakers you tried if you use the same drivers.

You kind of need to give more details, is price a factor? do you have a budget in mind? how about size and weight? some speakers are more suited to compact cabs than others. One of the things you seriously need to look at is Xmax, basically how far the speakers can move before the coil exits the magnet. There are plenty of speakers out there (eminence and celestion amongst them) which will handle 600W of heat but only 100W of deep bass because they are excursion limited. I haven't time tonight to look anything up but maybe you could give a few more details of what you are looking for.