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Phil Starr

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  1. 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.
  2. 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.
  3. 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.
  4. Phil Starr

    Porting Test

    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.
  5. I'm going to defend @Al Krow but then I'm out too, there are a couple of people here who have lost the plot a little and think by constantly repeating the same argument they can somehow 'win'. First of all I don't think Behringer can justify the 2000W claim even as a 'peak' figure. In the days of Class A/B we all knew that amps were absolutely limited by the maximum voltage the power supply could provide. The rms voltage was based on a mathematical calculation of the equivalent continuous power an amp would provide if it were supplying a continuous current. The calculation is called Root Mean Square and involves the square root of 2 which is roughly 1.414. The peak voltage an amp can swing is 1.414 times the 'average' voltage and as power is voltage squared x impedance the peak power is twice the RMS power. In practice the quoted power for amps is usually measured at a certain distortion level over a standard period of time. If you go back to most amplifier ads you'll see that almost all will say something like 500W continuous and 1000W peak and the peak figure is always double the continuous or RMS figure. Behringer are claiming more than double the power their amps make, whether you take the 500W or the unsubstantiated 800w figure. I think this is a deliberate attempt to deceive their customers. Since this is the sort of starter amp sold to less experienced and younger people I think it is dishonest, exploitative and possibly illegal. Just effectively saying 'we don't measure our amps in this way' is disingenuous and probably untrue. Until recently their manuals were refreshingly honest and the handbooks gave accurate continuous figures, they now seem to have abandoned that practice and it is not possible to know what power the Beyron produces from anything Behringer/Music Group publish. I'm not sure what point a couple of our members are trying to make, that it's OK to lie and deceive. That there should be no consumer protection.
  6. Phil Starr

    Bass drum mic creating havoc with my sound

    I was largely sticking to one point for clarity. I don't know exactly where this drummer puts his 'back line' but if it's behind the kick mic it's just daft, but the solution as you pointed out is to let peace reign and to talk things through. At the very least the drums should go through the PA. I personally like the sound of a good kit way better than any miked through the PA drum sound. I also like to keep it simple and would rarely mic up a kit unless I really had to, but my current drummer who is also a pro sound engineer likes his processed kick sound, and there have been drummers on this forum who have said they just use their kick as just a trigger and put a sampled kick sound through the PA. No accounting for taste but it can sound good done well and isn't wrong as such, just different. So yes I'd do it your way but working with a drummer who likes to always be miked up I'm learning to adjust, accept that it's his way and listen to the overall sound we achieve. I'm also asking if it's possible that if the OP is using a Fiver and has a particularly bassy eq set up to sound good at home and used unmodified at the gig. If so it seems likely that he has boosted bass in the kick drums lower resonance which is causing the problem and making the drummer think his kick can't be heard. Sort of volume war at 40-60Hz
  7. Phil Starr

    Bass drum mic creating havoc with my sound

    I'm going to play devil's advocate here. You can do things like apply compression and eq to a miked kick and a drummer may be fond of that sort of tone. By and large kick is the drum you can't hear out in the audience without some sort of boost and not all drummers are shed builders. Equally anything below about 60Hz is usually an embarrassment of riches for most bass. It may be that by using a five you are encroaching upon his frequencies a little. As a band you'll sound best if you can lock in with the kick sonically as well in your timing. I suppose I'm saying be constructive. This is a sound engineers view. "A common trick to getting a unified sound between kick and bass while retaining clarity is to boost the lows on the kick (60-80Hz) cut the low mids anywhere from 150Hz to 400Hz (sometimes called the mudrange) and boost the highs at around 3000Hz. This will provide a solid low end, remove some of the mud in the midrange and accentuate the attack of the kick pedal on the drum. For the bass, we do pretty much the opposite; cut the lows where you boosted them on the kick (60-80Hz) boost the bass at around 120 – 150Hz which will provide a full bass sound (while occupying the frequency space we made by cutting the kick drum in this range), and boost the highs at around 900Hz since bass also provides information in that range as well. In short, we are emphasizing the frequencies that are important to the sound of each, while cutting the frequencies where they can conflict. Try this technique. You’ll get a full bottom with a clear thump with a defined attack in the kick and a clear, full bass."
  8. Bill's advice is good. All usable frequency (-10dB) means Is that there is some sound you can still hear at that frequency, which is conveniently the fundamental of bottom E. Below that the sound will have fallen off enough for you to no longer really be able to detect it. In any case as Bill has said most of your sound is 2nd and third harmonic so you'll still hear the notes with a five string, just not the fundamental. There is a very tiny possibility of damage below this frequency especially with ported cabs. Subsonics which you can't hear can cause huge cone excursions which can cause speakers problems so do listen out for signs of stress. It's good practice to filter out subsonics as it reduces cone excusion without noticeably affecting the sound. Your's is a loud cab so will probably do every thing you ask of it without distress.
  9. Phil Starr

    Class D power Amps Advice

    Looking at the Engl it's a proper bass amp, if you are running off a pre you re doubling up on controls you don't need. The Engl looks to be about £600 compare that with the Crown XLS 1002 at £250 less than half the price and just a smidgin more powerful at 700W into 8ohms bridged. that's only one example of course but you can see what you'd save by cutting out the duplication of controls. https://www.thomann.de/gb/crown_xls_1002.htm?sid=6b46c732568192769a8afadf8b00da20
  10. Phil Starr

    Auditioning New Band Members

    The main thing is to be sure you know what you are looking for, that applies to any audition and pretty much any job interview. A new singer is probably the most disruptive thing that can happen to most bands. If they sound good the whole band sounds good and if they aren't it won't matter how well the rest of you play audiences won't enjoy what you do. On top of that voices are far less flexible than most instruments. Capo-ing a singers neck is probably illegal Is it important to you to keep your current set? If so then you really ought to put them through their paces with the whole vocal range of your songs. We've had singers who have struggled with fast articulation (lots of words in the line) some where the lower range is weaker other where top notes are the problem, you need to think about what is important to you as a band and pick out some songs which will explore this at the audition. Then you need to find out if these people will be good to have in the band, that isn't just about how charming and friendly they are, most of us can do that for an hour or so if pushed. Are they going to practice before rehearsals? That'd be one of my criteria so I'd want at least one song they are unlikely to have sung before, you'll soon see who is blagging and who is prepared. Again what is important to you? You also want to be fair to them and see them at their best. It'd be a shame to pass up on the next Freddie Mercury because you didn't let them show what they can do! Let them choose at least one song, maybe it will have to be from your set list or sung with just a simple accompaniment so the whole band don't have to learn a new song for each singer. So go through a list of things that are essential to you and things you think are desirable and make sure your audition songs will give you the chance to explore that. Also make sure the band are ready, I've gone to auditions with agreed songs to find out half the band members don't really know the songs or haven't played them for years and have done zero preparation. Good Luck
  11. Phil Starr

    Class D power Amps Advice

    This is a fairly mainstream approach now. Class D PA amps are really relatively cheap compared with dedicated bass amps simply because they are mass produced. You can get quality amps like Crown for relatively affordable prices. Unfortunately they tend to be in 2U format but you should be able to buy something that will produce well in excess of 1000W in bridge mode for less than £300. Just check what the minimum impedance is though, they will want to see twice the impedance in bridge mode to the minimum impedance in stereo.
  12. just at a technical level probably not, it may be the least important aspect in terms of the sound the amp makes. Any shaping of the sound will be done in the pre amp stage and the ultimate way the amp deals with power demands will depend largely upon the design of the power supply. Most modern amps can give plenty of power and at minimal distortion and the power amp stage will be designed to be flat response within the audible hearing range.
  13. Phil Starr

    Not Very Interesting FRFR Story

    That's a good point, though it is interesting that all DSP actives don't sound the same. The other side of DSP is that there is usually a lot of other management going on. Active crossovers with bi amplified speakers are a real positive but you'll also be getting a fair amount of compression in many designs optimised to favour PA use rather than bass. My guess is that many of these things wouldn't be noticeable in a live band but I'd be interested in people's experiences.
  14. Phil Starr

    Not Very Interesting FRFR Story

    Don't give up quite yet John. It's pretty obvious you want to discuss bass speakers not hi-fi (so called or not) Given that it is the speakers part of Bass Chat that doesn't seem too unreasonable I think all you are saying is that the other very long FRFR thread is for those who are going down the route of using PA speakers and you want to share your experience of a passive FRFR cab designed for bass only and maybe started a debate with other people going down the same route. I'll declare an interest in that I've seen your speaker being developed from my original single driver flat but not very extended frequency response design. I'd start off by asking how it has worked out, you started out pretty much just adding a simple horn and crossover but ended up with a really high quality horn and much more sophisticated crossover with a measured response which is as near as can be flat. How does it sound and does it achieve what you hoped? Will you be going back to a typical coloured bass cab any time soon?
  15. Phil Starr

    Daisy chaining cabs with different ohms & cones

    Hi Al, it's genuinely complex isn't it? One of the complexities is that a lot of the 'information' is also advertising. For example your 'well known manufacturer' who is quoting a 15" cab running from 25-2k is probably stretching things a little. If the 15 is flat down to 25 Hz and can handle any power it will have to have a very heavy cone and a long throw, both of which would make it very inefficient. More likely it is 10-20dB down at 25 Hz so it is making some sort of sound but just not loud enough for you to hear significantly. The 1x12 may sound good with their 2x10 but if one part of their claim is improbable can you believe anything they say? A speaker that only goes to 2k wouldn't be suitable for bass on it's own. All this means is that you couldn't tell anything about how the cab would sound just from a bald 45-16k frequency response. Is that at -3dB, -10dB or some other figure. Is the response flat between those two extremes or biased towards some frequencies more than others. Add in one more factor, how we perceive sound. It is just like everything else to do with our senses, an entirely subjective experience. What we think of as bass is often about what is going on elsewhere. If I'm trying to pick out a bass line from a recording I usually cut the mids and tops rather than boost the bass. That'll make the bass line stand out much better than boosting bass 95% of the time. If your cab 2 had a bit of a mid/top end boost it would sound brighter even if the bass end was exactly the same. It might not be the 5Hz quoted difference in 'cut off' that creates the difference but what both cabs are doing in the 100-200Hz range that you are hearing. The best way of judging any cab, particularly an instrument cab is by ear. Test gear will help anyone designing a cab but you can't really drag it along to a music shop. Published figures without any indication of how they are measured aren't always a lot of use. I'm not completely cynical about manufacturers but it's a tough world for them too. If they use 'honest' rms watts and +/- 3dB frequency figures and so on then they are likely to lose sales to people who use peak figures. I'll get back to you on what in principle might be the difference you'd hear if the figures were independently measured and so could be compared, that's another long story.
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