flyfisher

Yep . . . or a better sound engineer.

Well, increased complexity can mean less reliability although the PC I'm using for this post contains hundreds of millions of transistors. I reckon reliability is more to do with the design approach rather than the design itself. For example, if a transistor is required to handle 10A then an over-specified part that is actually rated to handle 20A is likely to last longer. A crude example, but you get the idea. Using a car engine analogy again, It's quite possible to get 1000bhp from a 1500cc engine (as F1 used to allow) but it's going to be more reliable churning out 90bhp in a family car.

Exactly. All it does is [u]alter[/u] the pickup characteristic of the mic, so it might make things better or worse, as can just moving about in front of the mic if the system is on the verge of howling.

Yes, with the exception of a pure sinewave, which is a single frequency, a waveform is made up of many frequencies of varying amplitudes. The waveform depiction you see on computers (and things like oscilloscopes) is a visualisation of the waveform in the 'time' domain. It shows the amplitude of the wave over time. The wave may be represented by a voltage or by air-pressure but in all cases the time-domain display just shows how things rise and fall over time. The time domain display doesn't display the frequency components of the waveform. To see the frequency components, a spectrum analyser is required. Such a device is said to operate in the frequencydomanin can analyse the waveform and separate out the individual frequencies contained in the waveform and display them as individual components

[quote name='Lozz196' timestamp='1335517844' post='1632391'] I`m sure I`ve read on here that if you do this, the load will be about 5.6 ohms, so in theory that should be ok. [/quote] I'm not familiar with that amp but if it's two separate power amps (channels) then I can't see a problem as it's just like having two separate amps only they're in one box. I don't understand the 5.6 ohms thing though because the two speakers would not interact with each other. One channel would be driving into 8 ohms and the other into 4 ohms, with the power implications that [b]xgsjx[/b] described above.

[quote name='Phil Starr' timestamp='1335512976' post='1632300'] It's all a bit like modern cars, better cheaper, more reliable but buggers to work on when they do break down. [/quote] Not a bad analogy. A modern, hi-tech, fuel-injected, turbo, multi-valve, computer-controlled marvel of engineering design or just a large capacity V8 full of 'grunt'.

To be honest, I can't say I've noticed a big tonal difference between a 210, a 115, a 210+115 or a 210+210. I've probably got cloth ears. But I do like the flexibility of being able to mix and match and two 210s are physically easier to handle than a 410.

I've never heard of the skin effect having any significant effect at audio frequencies, though it's certainly important at radio frequencies. Some background here: http://en.wikipedia.org/wiki/Speaker_wire [i]"Regardless of marketing claims, there is negligible harm done by skin effect in typical inexpensive speaker cables. The increase in resistance for signals at 20,000 Hz is under 3%, in the range of a few milliohms for the common home stereo system; an insignificant and inaudible degree of attenuation.[/i]"

[quote name='Pinball' timestamp='1335348873' post='1629541'] I have an Mag 300 Evo 11 amp and the chance of some 2nd hand cabs but am confused over cabinet choice. Putting ohms asside because they seem fine (8 ohm). The output of the ashdown is 300watts but there are two jacks out. My guess is that this means it is 150w ber channel if both are used to a 200w or 250w cab would be fine. Am I right or heading for disaster? [/quote] Not quite right, but you're not heading for disaster. I have the same amp and it does indeed have two jack outputs, BUT there is only one amp output 'channel'. The two output jacks are simply wired in parallel to make it easy to connect two cabs. The amp is (from memory) 307W into 4 ohms. But you won't get that by plugging in a single 8ohm cab and a rough guide is that a 4ohm amp will output about 2/3rds the power into 8ohms, so about 200W in this case. If you connect one 8-ohm cab the amp will drive it with about 200W. If you connect two 8-ohm cabs then the amp will deliver about 300W split 50:50 between the cabs or about 150W each. So, in all cases, 200-250W cabs will be fine and nothing will come to harm. FWIW, I started off with 210 and 115 cabs but I later added another 210. This gives me the option to have a 410 stack arranged vertically (which is the supposed ideal) and having two cabs means for a lighter lift. Works for me.

Won't do any harm to give it a try, but even if it's OK at home you'll always be worrying about interference if/when you play in a different location. Not to be recommnended really.

All of this merely highlights the very different personalitiesto be found in bands. If they are a good (or bearable) blend then the band survives, if not the band will eventually break up. What won't happen is changing someone. I play in two bands. The guitarist in one has half a dozen pedals in a pedal case. He turns up, opens the pedal case and is ready to play. Everything is already correctly wired up, the pedal settings are all correct and he knows which pedal(s) to use for each song. The guitarist in the other band has a similar set up and a pedal case. He turns up, opens his pedal case, messes about with the wiring, plays about with the pedal settings, is unsure about which pedal to use at first, but gradually remembers after about half an hour. In one of the bands we also have another guitarist who plays an acoustic for some songs. Without fail, when setting up his amp he'll plug it in with the amp on full volume leading to howling feedback and his tone and effects controls are always all over the place at the start of a session. I've lost track of how many times I've suggested using a marker to remind him of the basic settings. When not using the acoustic, he'll put it on a stand near the amp without turning down the volume, which generally results in a slowly building howl. His shambolic approach has been an open joke for a few years now but he never seems to learn. It's just the way he is. But all of them are lovely guys, they're just different personalities and I can't see them changing any time soon.

Yep, I'd agree with all that, with the possible pedantic exception of using 'waveform' rather than 'wave' to describe the 'pressure waveform' containing all the 'data', which arrives at the ear to be converted into sound 'information' by the brain.

[quote name='leftybassman392' timestamp='1335020246' post='1624822'] Long story short - speakers transmit waveforms, brains detect sounds. Simples. [/quote] Well, yes, but our brains detect [i]everything[/i] we perceive so I'm not sure that really helps answer the original question. Eyes receive light, brains make pictures, etc. A speaker may only transmit a waveform, which as you rightly say can be displayed on an oscilloscope without needing a brain to hear the 'sound', but that waveform is comprised of many individual frequency components, which can also be displayed on a spectrum analyser without needing a brain to hear the 'sound'. That's basic physics. How the brain makes sense of the received air pressure wave "data" and turns it into sound "information" is indeed a very complicated matter, but the incoming waveform has to somehow contain all the necessary "data" for the brain to decode in the first place. Surely the "data" are the individual frequency components that make up the complex waveform in question?

Can't be anyone here can it? I thought we were all bass players.

Hmm. Seems like this could do with some more detailed definitions of what's meant by "one sound" or even "one waveform". I'd agree that a speaker can only produce one waveform, after all it can only move back and forth, but one waveform can contain many 'sounds'. Thus a single 'sound' is a collection of individual frequencies, hence my earlier point about an "A" played on piano as sounding different to an "A" played on a guitar - a single 'sound' but many different frequencies at many different amplitudes.

You could probably do it by disconnecting two of the speakers . . .

[quote name='essexbasscat' timestamp='1334922273' post='1623471'] Question. Using entirely hypothetical, random figures here; If one instrument plays a note of say 240 Hz and a second instrument plays a note of 435 Hz, why does the speaker produce two notes and not the one note associated with the sound of 240 + 435 = 675 Hz ? [/quote] Thing is, if one instrument produced only 240Hz and second produced only 435Hz then apart from the actual note both would sound identical. But they don't sound identical because they don't produce only a single frequency. This is why a an "A" sounds completely different when played on different instruments - it's the harmonics that give the tone. So, if a speaker could ONLY reproduce single frequencies at a time there would be no long-winded debates about 'tone' because alll instruments (and not just basses) would sound identical.

[quote name='Dr.Dave' timestamp='1230373034' post='364072'] I'm no sparky but I should think an 18v is more reliable. 2 batts are less likely to die a sudden death than one so there should always be more nosebag for the eq circuits to feed on. That's how it was explained to me anyway. [/quote] I can't see that myself. If the circuit needs 18v then it's unlikely to work very well with 9v. This is especially true if the two batteries are connected as "-9 : 0 : +9" where one dead battery will mean the loss of one power rail and a very nasty sounding output. It would be possible to combine two 9v batteries for redundancy, but that would be no different to using a 9v pre-amp with a larger battery. Besides, if you have two batteries you have twice the chance of a failure than with just one - so there's no great reliability advantage.

Having just re-skimmed this thread I'm surprised nobody queried whether "18 volts" is actually "-9 to +9" volts. Op-amps require a +/- power supply around a 0v reference level. The audio waveform will alternate around this 0v reference level. Thus the "0v" output level of an op-amp powered by a single 9v battery will be 4.5v (known as a DC shift) and the audio waveform can alternate between 0v and 9v. With two 9v batteries, the op-amp power supply can be arranged as -9v and +9v with and the "0v" reference level will actually be 0v. Thus the "0v" output level will be 0v and the audio waveform can alternate between -9v and +9v. This might seem a subtle difference but it means the amp can be DC-coupled to the next stage(the bass amp). A pre-amp with a 4.5v DC shift would need to be AC-coupled to the bass amp in order to eliminate the 4.5v offset. Having said all that, I'm not that familiar with guitar pre-amps but the above certainly holds true for op-amps. As an aside, AC-coupling is commonly used in audio (and video) equipment, specifically to avoid the build up of DC offsets between connected equipment, and such capacitors will have some effect on the 'flatness' of the audio signal. In some circumstances, comparisons between the 'sound' of 9v and 18v preamps might be little more than the comparison between AC and DC coupling.

[quote name='essexbasscat' timestamp='1334850248' post='1622359'] How does a speaker make more than one sound at a time ? [/quote] In the same way that a bass string makes more than one sound (frequency) at a time - it has multiple modes of vibration.

I can't outplay the bass I've already got so I'd spend the £5k on sailing aound the Carribean for a few weeks.

Yep. And let's face it, given the number of times this sort of issue crops up, some cab manufacturer somewhere would have included a simple "4 or 8" ohm switch by now if it was actually possible.

It sounds as if what you want should be possible but I had a quick look in the Voodoo manual and couldn't find any details of how to wire up such cables. It's not clear if the device supports simply wiring the various outputs in parallel for more current or if the adapter cables would need diodes to isolate the outputs from each other. Or maybe they already have internal diodes? Might be worth sending your question to Voodoo Labssupport. looks like they have an active forum at http://www.voodoolab.com/support.htm

Ask the interested agent what the going rates are in your area? I'm sure they'd want as high a price as possible.

[quote name='SteveK' timestamp='1334434261' post='1616270'] Can't help thinking that maybe Bill Curbishly has been a little naughty and told only a part of the story. The Olympic organisers can't possibly be that dumb...can they? [/quote] My thoughts exactly.