Phil Starr

I'm assuming this is a serious question. The only fair test is to change only one variable at a time so if all you want to know is what the amplifier does then that's the only bit you'd change. If you change both the speaker and the amplifier you won't know which may have contributed to a change in volume. So long as the speaker can handle the signal without compressing you should get your 4.77dB extra. If you change to a speaker with a lower sensitivity it will be quieter with both amps but you'll retain the just under 5db difference, just at lower levels.

Before anyone else tries to confuse the issue any further. I'm assuming for the sake of simplicity that we are using the same speaker, that speaker can handle the power adequately and that the same eq is applied to the signal. I'm also assuming that we have turned up the volume control to the point where the same level of distortion (let's say to DIN 45-500 here so 1%dist and the amp is running for 10mins and the temperature has stabilised) All of those things are implicit in my post which would have been far too long otherwise, as well as not being very helpful. OK which 'expert' thinks the 300W(EIA, IEC,DIN) would not be louder by 4.77dB than the 100W(EIA,IEC,DIN) amp. I'm surprised some people don't know how to calculate that themselves Level in dB: L = 10 × log (power ratio)

That's why I specified the same speaker.

Not wanting to get dragged off the point here but wherever there is a difference between perceived volume and actual volume there is a technical reason for the difference, that's the reason I keep posting to try and explain the technical side. I simplify things a little sometimes but in this case I specifically said through the same speakers, so same efficiency and same frequency response. In which case the same loudness. Valves are a special case, they compress the signal at high levels. If you used the same amount of artificial compression you could get the same sound levels out of a SS amp. I love the sound of a valve amp, they sound magic but there isn't magic inside, just engineering. People do, and should, buy amps and rigs based on sound alone. In the end that's the only important thing but some people are curious about the technical side of things and it can help you home in on what you are seeking having a little knowledge. I don't think anything you said was wrong but the statement you quoted is correct. A 300W valve amp will be louder through the same speaker as a 100W valve amp.

At the risk of stirring up another hornets nest I'd like another go at this. I don't think it's difficult to understand and it's a helpful concept. The first thing to say is that watts are real and that they do matter. An amp with more watts will ultimately be louder than one with fewer watts through any given speaker. If you want it louder then you can increase the watts, or improve the speaker or a bit of both. If you are buying an amp (a head rather than a combo) then the wattage is one of the things you should know. One of many, but one of the big ones. Watts can be measured (this is Wikipedia) 'The watt (symbol: W) is a unit of power. In the International System of Units (SI) it is defined as a derived unit of 1 joule per second,[1] and is used to quantify the rate of energy transfer.' So long as you all stick to the same system of measurement then it's a simple measurement and most secondary school students could do it. You can convert watts into any other measurement of power, so 745W is one horsepower. (That's brilliant, my Mark Bass Tube is 0.67hp, should all valve amps be rated in horsepower or British thermal units ) That's where the rms measurement comes from. if you have a direct current running a motor or a heater than measuring the power is simple if you know the current or the voltage and the resistance. When someone had the bright idea of using an amp to control a motor then you need a way of converting. The average voltage of an amps output is zero as it goes up and down with the waveform, but mathematically if you square the voltage then all the minus's become plus's and you can work out the average or mean. Then if you find the square root of the that average you can compare ac watts and dc watts. Its the root of the mean of the square... RMS. Of course if you just use the amp to heat an 8ohm resistor it will do the same thing, you can compare the energy being transferred, just less accurately. In the start of amp design that's how it was done. All controlled by engineers you see, honest, measurable, repeatable. then the ad men got involved. To be fair the engineering method could reasonably be said to be over-doing things for music. Music has loud bits and quiet bits, bits where the amp isn't making heat into 8ohms and the amp can cool down. That means you can make an amp with less cooling built in and use a smaller power supply saving weight and cost. It makes engineering sense to use an amp that can make it's power for a limited duty cycle, say 20% of the time. That's where the confusion comes in you have to have a standard that everyone agrees on or people cheat. Rms all the time, 20% of the time or just for 0.01 of a second at a time? In Europe the DIN 45-500 standard held sway for a long while it is basically an rms rating which the amp has to produce for 10 minutes with a pink noise signal filtered to contain a similar spectrum of energy to real music. EIA RS-426 and IEC 268 used outside Europe are broadly similar. It's a fair test for audio amps and it ought to be used. Behringer used to give rms ratings based on IEC/EIA measurements. It's a bit like cars and their fuel consumption figures. You probably won't get the consumption they advertise and some will be closer than others depending upon the detailed design of the car but it's a good start and cars with similar figures will give broadly similar performance. You know the test isn't perfect but that it is fair and good enough to be a big help when choosing what to buy. When somebody like Volkswagen cheat eventually they get caught and everyone knows they are cheats, people lose their jobs and fines and compensation come into play. The same with food standards. Why should consumer electronics be any different?

Sennheiser HD201's cheap as chips 3m lead sound great with bass Mine are about 5 years old and are still going strong

I suspect they'll be 8ohm speakers, the 4x10 in the Hydrive series is an 8ohm cab and the 2x10 a 4ohm cab. If that's right then your 4x10 will be 8ohms and you can either wire your 2x10 as 4ohms or as 16.

If this is the current version with the neo drivers then you should have no problems. a quick look at the manual shows the cab is in fact 4 2x10 cabs internally and a sealed cab so essentially you could just build a 2x10 the same volume as 1/4 of the cab you have and you'd get the same sort of sound but quieter and without the horn. Or a half sized 4x10, with or without horn. If you use the horn you may need to tweak the crossover but someone here may be able to help you with that. I'd probably go for a 2x10 with the horn in and another with no horn. That way you can take one cab to most gigs or both if you want a bit more oomph. If these are the neo drivers you can probably sell the spare drivers for a decent price. Without knowing anything about the drivers specs it is possible you might be able to put them in a ported cab and get a bit more bass out of them, it would change the tonal balance but that might be a good thing. Reckon to spend about £50 on each 2x10 (a 4x10 is only going to cost about £20 extra as it's only the extra wood) by the time you've bought all the handles corners trim and so on. Then think what the 8x10 is worth and what you'd have to pay for a 4x10. If you decide to go ahead you can get a lot of help on this forum.

I'd absolutely go for those bars rather than the party light T-bars, I have both but the T-bars are cumbersome space guzzlers best used for blinding musicians and I only use them for lighting the audience nowadays, I have a 12 way 1metre strip which goes behind the drummer as an uplighter and some of the round PAR lights but I'm going to get a couple of those short bars for the speaker poles.

Win ISD will cope with two ports but assumes they are both the same length and size. I wouldn't want to have to do the calculations for two ports so completely different. Conventionally you'd treat two ports (or any number of ports) as if they were a single port with the same area as all of them combined. with a 55mm and 75mm port that equates to a 93mm port. Remember the volume of the cabinet is decreased by the ports and the volume of the speaker itself so this is probably a 30l cab in reality. The 75mm port is nearly twice the area of the 55mm port 44cm2 plays 24cm2 so you should have a noticeable improvement with just that change.

Stevie is right, that looks like a decent speaker, that's quite a big magnet compared with some OEM drivers. I think it unlikely you'd get a huge improvement in output just by swapping it, though you might get a tone you'd prefer, or not. I thought I'd answered this but maybe someone else asked a similar question. Since you are thinking of building another cab then one option would be to build a cab and try out a speaker by disconnecting the internal driver and plugging in the new one. That way you'd have your extension cab and would be able to compare it with the original Ashdown driver. Actually if you can find people with 1x12 8ohm cabs of around 37 litres you could even try those out without having to build anything. I'm currently using the Beyma SM212 in a 30litre cab successfully and modelled it in a 40 and 35 litre cab where it modelled well. so it might be a candidate. It may be that Ashdown could provide you with an 8 ohm driver if you tell them what you are trying to do, they are exceptionally helpful. The thing to realise however is how subjective our impression of sound is. A lot of what we perceive as bass is actually around the 100Hz area, deep bass is often a bit of an embarrassment on many stages, Heft? I'm really not sure what that means and suspect we all hear it differently. However changing drivers is going to change the upper range of your bass quite a lot too and you will hear those differences much more than any small changes in bass output. your difficulty will be in not knowing what the changes might be until it is too late and you've bought a speaker you aren't happy with. However having two drivers will really increase your efficiency and your maximum output, you'll be able to run your amp lower or decrease the distortion when you run at high levels, you'll be able to use a bit more bass boost if you need it, raise your speaker off the ground nearer your ears so there are lots of gains to be had potentially. An 8ohm combo with n extension speaker is a very sensible way to go. On the minus side what would you get if you sold the Ashdown, add in the cost of two 8ohm drivers and ask what you would/could buy with that sum. £200 plus the Ashdown might offer you more for your money with the chance of trying it before you buy.

The answer is in the price. Aluminium is a light metal but even so it's way denser than wood so you have to mould /cast /extrude it into shape then use fairly complex techniques to make that into a cab. The machinery to work wood is cheap and simple too It's not all positive either, you can achieve a reasonable rigidity easily enough but metal is less self damping than wood so it sets up it's own design challenges. There were some interesting hi fi designs in the 80's that used honeycomb aluminium but they were very expensive, as is the MB150. Basically there are marginal gains for a large cost and that money might be better spent on other parts of the cab/combo.

Good advice but a couple of points that you might like to consider. You said you are mixing from on stage. I'd be thinking about something with some physical sliders for those moments when something goes wrong and you need to tweak a channel and keep the music going at the same time. Pretty tough to use a touch screen and play bass at the same time but hitting a physical switch or fader if you've forgotten to change scene is a bit more practical. The other consideration is the vocal mics. I've got 3x AKG D5's and the sound is fantastic and they are a bargain but the downside is that they are fairly demanding of your mic technique, you have to keep your head fairly still as going even slightly off axis or misjudging your proximity kills the volume, the downside of their feedback rejection. Mic's suit some voices better than others and some singers prefer a less demanding cardioid mic. (secretly I like the rest of the band to use the predictable, reliable, good sounding D5's but I am rubbish with them and use a Sennheiser 935 or a Shure) I'd really look at the RCF 735's though, you'll get a better sound than most of the tops and subs mentioned here and cut down on the hassle factor. It'll be a long time before you need any more than this and you can add a sub or two if you need to once the money starts rolling in, personally I suspect you won't.

Oh there are some nice reviews here http://microphonegeeks.com/pro/live-microphone/

Steve we are living parallel lives. Sennheiser 935's and AKG D5's are what I've ended up with. I think you'll like the 935's. They are actually similar sounding to the AKG D5's but the D5's are incredibly directional and I can't keep my head still enough when I'm playing bass, great sounding for the money though. That's a great price for the Sennie's too, way less than I paid a couple of years ago. The only alternative I'd have recommended without going to silly money would be the D5C's, AKG have bought out a cardioid version of the D5 which wasn't available when I bought my 935. Haven't had a chance to try one yet but I love the sound of the D5 so if it provided that sound but was more tolerant of a hyperactive bass player it would be very interesting. My other mic? An EV 757 PS for anyone looking at the Behringer, it's OK we did an A/B with an sm58 years ago and it possibly sounds better (but not by much) but it's supercardioid and has worse handling noise, ours needed a wire resoldering which had been cut too short in the factory straining the soldered connection but otherwise it seemed pretty solid.

Funnily enough I watched one of these last night. By the time Scott reaches the 1970's it's all about the bass and the technical gifts of the bassists and bands less well known songs that happen to have extraordinary bass lines. Now I would love to have a fraction of the skills and musical intelligence of a Scott Devine but the music left me cold. I can appreciate how good these players are but for me it's a bit of a musical exercise, a great work out for something with a bit of meaning later on which never happens. Yet I get real pleasure out of a great bassline and as a non musician of 55years turned player I get more pleasure now I have a little understanding. Listening to Graham Maby on the Joe Jackson songs is a real thrill now I know a little more. For me though it is still the song first and the musicianship further down and I'd take an Andy Fraser over a Jaco any day. It changes all the time though, the better I get and the more I understand the further I'm drawn into the technical aspects but I hope to always be more of a bass-watcher than a twitcher.

That's true to an extent, there's a lot of cabs where each 10" driver is mounted in a cab with about 25l to work in and they are often tuned to somewhere around 50Hz but I also know of one person here who fitted an expensive neo driver into a cab of the wrong size, blew the speaker and found he had invalidated the guarantee by using a poorly sized cab. Having an incorrectly tuned or sized cab can reduce the power handling of a driver down to a few 10's of watts. It's not going to happen every time but worth asking someone to check.

having recently had a look inside a Behringer cab I'd say the problem won't be that it is badly made but that they skimp on materials. The speakers I had were perfectly good but had very small magnets. I'd imagine they would run out of excursion fairly early so wouldn't handle any great power, the cab I had was nicely put together but made of MDF and consequently quite heavy. If you want to find a speaker that works you need to tell us the internal dimensions and the size of any port.

I think you will struggle but if you feel there is nothing to lose try a bit of steam, it'll soften the lignin fibres and maybe even break some of the chemical bonds which tie the fibres together, they'll reform over time and as it dries. It's the process by which wood is bent and it works fairly well on flat paper, a cone is going to be tricky, ideally you'd want a mould to shape the cone onto and a way of clamping it whist it dries in the shape you want. Sounds like a tricky job. good luck.

OK, I'll bite Why a 2x8? It's an unusual starting place, did you start with a particular driver in mind or a design aim you didn't feel could be achieved with a more conventional design? What are you after? Talking through a design process or just having your numbers checked?

We live in a frustrating world where things like fuses can pretty much only be found online. Hope you bought a lot of them. Even so I'd only try one more fuse, it that blows it isn't coincidence there's a fault and I guess that's not something you'd want to fix yourself. It's impossible to guess what's wrong from a distance but my experience is that there is a problem with the power supplies in the HA3500 with a lot of moderately sized capacitors slightly insecurely mounted on the circuit board. Over time these can pull away and even damage the board by pulling the tracks away. The good news is that unlike more modern amps the Hartke is easy to work on and the components are generally widely available and low cost so your bill shouldn't be too expensive. They are a lovely sounding amp though.

Fair enough. If we assume the Bugera is a well designed class D amp with an efficient power supply and draws 880W from the mains and can run continuously at that level then it is probably around 80% efficiency and can supply about 704W. That's with an undistorted sinewave within the passband of the amp. That's the value of what is normally described as the RMS or continuous value. If you look at section 3.2 of the Wikipedia article then you see the peak power of a sine wave is twice the average power. So if it is a 704W amplifier than the peak power is 1408W. If you look at a range of amp and speaker specs you'll see that there's a fairly consistent description of things described as 500W continuous 1000W peak, 200Wrms 400W peak and so on. It's a simple mathematical ratio which enables those who want to boast that their system is 1000W but allows for fair comparison. Actually it is meaningless as it is always double so no extra information is being given. If any other figure is given then as the Wiki article says about PMPO there is no accepted way of calculating the figure and it is without merit. Basically the sums don't add up. you can see my disquiet if you look at the advertising, here for example https://www.gear4music.com/Guitar-and-Bass/Bugera-Veyron-BV1001M-2000W-Bass-Amp-Head/1WNV lot's of mentions of 2000W no mentions of peak power here, I suspect both Gear4music and Music Group know people will choose this amp on the basis of the 2000W and it looks a lot better than the Little Mark 3 https://www.andertons.co.uk/bass-dept/bass-amps/bass-amp-heads/solid-state-bass-amp-heads/markbass-little-mark-iii-bass-head In practice I suspect they would produce very similar power levels. Even if the Veyron is 700W and the LM3 is 500w that difference will only barely be audible. Sensibly you'd decide on tone (I hope!) reliability, after sales and price rather than power but for someone with no technical ability that 2000W looks so tempting. If we accept this then Markbass would eventually be forced first of all to sell their amps at peak power of 1000W and then start making up figures to compete. I think it's a better world where honesty is rewarded and we ask for proper measured ratings which can be compared fairly.

OK then that explains perhaps why you have concerns and why those of us who have dealt with these issues over a number of years are so frustrated with you. It's a simple matter of misunderstanding. Measuring an amplifier's output is basically very simple. You connect it to a big resistor of 4ohms (say) put a signal into it and increase the signal until it starts to distort. At that point you measure the voltage the amp can do without distortion (less than 1% is the usual measure) and then the power is voltage squared divided by the resistance. Conventionally this is measured over the whole range of our hearing 20-20,000Hz. It's slightly more complex for a class D amplifier as this operates on high frequency pulses all at the same voltage but passing it through a low pass filter makes comparable measurement possible. In the US there is long standing Federal legislation to stop misleading claims by advertisers and in Europe various standards exist with the DIN standard widely known. https://en.wikipedia.org/wiki/Audio_power There's some good links at the bottom of the article if you are interested. You simply cannot design an amplifier without knowing all of the parameters and indeed specifying all the parameters of you amps so the claim of 'we don't know the rms power' or 'we don't calculate it that way' isn't credible. Another factor is the input power, an amp cannot put more power into the speaker than it takes from the mains. In fact it will lose power both in it's power supply and in the amplifier itself. A class D design with a switch mode power supply is likely to be somewhere in the 80% efficiency range, so if the amplifier has indeed an input rating of 880W then it can only put out 700W. Then there is the long history of Behringer over claiming power outputs in their advertising. For example I own an old Behringer EP2400 PA amp, claimed output 2400W. When you delve into the manual as I did before I bought the amp I found it would produce 285W continuous into 8ohms with both channels driven. I was using 300W speakers at the time so it was an ideal match and a lot of bang for the buck so a good buy. The over -claiming was irritating but I'm a scientist and the data was all available. With the Beyron it isn't and Behringer are no longer publishing all the data on a lot of their gear. I think it's pretty stupid really as a 500W amp at this price is still beating the whole market and false advertising just makes the company look suspect and contemptuous of their customers. As a 'Physics person' I come on here to repay all those who have helped me with my bass playing by advising them as best I can on technical stuff. I'm still enough of an old hippy to see the people here as friends and I don't want them conned. If someone delivered a Beyron to me it wouldn't be difficult to test it but I know more than enough to know that it makes way less than 2000W. If it is part of the decision of what to buy then I want people here to know what is true and what is incredible.

This is completely the point, watts are not subjective random nebulous things. they can be measured there is proof. So if a manufacturer lies there is an objective way of catching them out. Quite rightly there are laws against deliberate deception for financial gain across Europe, America and most of the world. Unfortunately not all our governments support trading standards enforcement as they should but that is down to the demands we put upon them as consumers and voters. Put your hands up those of you who support fraud. There are minor bickerings of course. An amp may supply 500w but only for a few seconds and another may do so all day, It may supply full power at 1% distortion or 3% distortion and maybe the power is rolled off at 50Hz in one amp and 20Hz in another but all of this is covered in regulations in different countries and only accounts for small variations in rated power. It is also true that few of us use all the power available to us from our amps and 250W is a lot of power which is enough for most of us. It's also true that some people like to play Top Trumps with power ratings. Plenty of people with cars with fourwheel drive and sport settings on their suspension never go near a puddle or racetrack but if they are being charged for something that says it does 0-60 in 5secs or 65mpg it should be able to achieve those claims in verifiable repeatable tests. Why would bass players or musicians exclusively agree to lower standards than the rest of the population. If an amp manufacturer makes a claim about their amp it should be provable and their responsibility to prove it. If they want to sell an amp with the claim 'loud enough' that's fine, a brave marketing strategy but up to them. The big problem is that if we let a few companies get away with it then others are forced to follow their deciepts or lose customers. It isn't just bass amps of course, we currently allow drugs companies to bury research which does not show the effectiveness of their products or identifies possible side effects. We know that it wasn't just VW who were fiddling their emissions data. Bass amps may be small beer in comparison but it is something we are all competent in and major consumers of. It's kind of important to call out this sort of behaviour as it happens. I'm perfectly happy for anyone to say a TC amp is loud enough or that the Bugera is great value for money, I can't for the life of me understand why some people are arguing that fraud is a good thing.

A ported cab works as a resonator. A Helmholtz resonator to be precise. Blow across the mouth of a bottle and it makes a note, half fill it with water and it'll make a higher note, find another bottle the same size with a different size neck and it will make a different note again. The air in the neck is bouncing on the air in the bottle and that is what makes the noise. In a ported cab the air in the port bounces on the air in the cab at the resonant frequency. At that frequency the port will make a sound, above that frequency the air won't move and the port won't do much and below that frequency the port is just a hole letting air in and out. The trick is to tune the cab so that it gives a little boost in output just as the speaker is starting to fade in it's bass so you get a bit of 'free extra bass' just as the speaker needs it. (a little more complex than this of course but this is the basic idea) Another advantage of all that resonance is that it creates a back pressure on the cone and stops it moving much so it won't move into the distortion and damage area as easily. In the case of your speaker it was almost certainly tuned too high, so you got the bass boost in the wrong place, lot's of uncontrolled extra high bass which you heard. Below that the hole meant the air was passing through the hole and that is why it was distorting and the cone was flapping around.