Chienmortbb

[quote name='Bill Fitzmaurice' timestamp='1484658293' post='3217213'] Even if they did there's another consideration. Going beyond xmax doesn't cause damage, reaching xlim/xmech does. The Beta 10 has 3mm xmax, with 8.6mm xlim, so there's a lot of room for overshoot. The BP102 with 6.2mm xmax will go a lot louder than the Beta 10, but with 10mm xlim there's a lot less overshoot capability, so despite the higher output capabilty of the BP102 you're far more likely to see them creased than Beta 10s. A minimum 2:1 xlim to xmax ratio is prudent. If that much is not available then it's wise to not only high pass but to limit the maximum voltage applied to the driver as well. That's seldom seen with electric bass rigs, but in high end PA it's SOP. [/quote]Bill the drivers in the example were chosen at random and I quite agree that exceeding Xmax is not a problem. XLim is the damaging area. However once you exceed XMax your driver is operating outside of the control of your amplifier and in a very non linear fashion, under only the the control exerted by the suspension of the driver and the "spring" in the cabinet.

Cooking up a storm I see. I have heard a older Barefaced but never played through one and I have never heard a Berg. However I know of enough people that have experience of both, on both sides of the pond to know they both make great cabinets. To say one is better than the other is silly. Better for whom? As for using the for sale section as in indicator of satisfaction, all that tells us is that more Barefaced Cabinets are sold second hand, on Basschat than Bergantinos. That is all, there is no evidence for anything else. It would be useful though if some of those that have sold both brands on here said why. I have no figures to prove it but I think Molan! Another dig at Barefaced, no evidence, just innuendo. I am an enginneer but spent a great deal of my time in marketing. I soon learnt that if you criticise your competitors you soon lose credibility with those customers that have had good experience with them. Your "basic integrity" is compromised and you will lose peoples trust. Now I am not going to buy either brand soon, I am going to build my own so have no axe to grind . However I hope someone will tell me what dealer you own or work for, as you have blown your credibility with me.

This goes back to the old problem of watts versus acoustic output and frequency. Our ears are highly attuned to the frequencies put out by electric guitars. a very large part of the bandwidth is the same as the human voice whereas out ears do not hear bass so well. Guitar speakers are efficient in getting those tones to us many giving well over 100dB 1w/1M in the area that guitars work. Most bass speakers are very inefficient so need a lot more power than guitars to sound loud. Lets look at two examples, The Fane Ascension F70 guitar speaker and the Eminence Legend B122. Thye Fane hase a sensitivity of 100dB in its useable response for guitar. The Eminence has a quoted 94dB sensitivity but its sensitivity at 50Hz is approx 85dB. Even at the published spec, of 100 and 94.1, The Bass speaker would need three times the power to give the same power at low mid frequencies. As we go away from the dusty end of the fret board and get down to low E our sensitivity is 82 dB and at Low B about 77dB. So to compete, sorry, blend wth a 20 watt guitar amp with the Fane, you need 60 watts. Oh but there is another guitar so you now need 120 watts add a drummer-240 watts, noisy drummer 480 watts, loud vocals? You can see where this is going. Of course you can buy a huge PA and put most of you sound through that. It needs to be huge though as PA speakers are not usually as efficient as guitar speakers and even our little guitar band would need thousands of watts to replace or just reproduce those electric instruments and mic up the drums. Now of course you also have to remember that the old bass cabinets were really guitar cabs and did not really reproduce the low notes until brands like Ampeg, Acoustic and Trace started make cabinets designed for bass. If you want to gig with 50W, build one of Bill Fitzmaurice's Jack speakers. They are horn designs and incredibly efficient.

[quote name='PaulWarning' timestamp='1484339101' post='3214875'] there's watts and then there's watts, my 200 watt Trace Elliot is just as loud if not louder than my 500 watt Fender Rumble, whether it's to do with the Rumble being a class D I haven't got a clue, hell I don't even know how they manage without a bloody great power supply [/quote]Trace heads were conservatively rated using a well proven Class A/B mosfet output stage. Fendet have a big marketing department. On a serious note, mosfets have a very musical compression at high power, not dissimilar to valves. It will probably sound louder in relative terms. I have only heard Rumbles at low volumes but the size of them suggests that full quoted output might be optimistic,

Approximately £17 per watt. Hmm!

Surely the point of a hifi cab is that you can get the sound you want with EQ. If you cab is "voiced*" In a particular way you can only fight it with EQ if you want something other than the standard "voicing".

I worked on Sony Class D amps around 1980. Like most technologies it takes a while for it to mature.AS for IEMs, I have seen a few pub bands using them and most seem to get their own mix right but the sound out front is either bad or at least lacking. If you use IEMs you need a sound man and a damn good PA, Two 15"s with a compression driver are not good enough.

[quote name='Ben Jamin' timestamp='1483351137' post='3206341'] The G&L's a weird one because it's an active bass with a switch for passive/active/active with high-boost - but the pre-amp is all passive (treble cut and bass cut, series and parallel) so everything works the same in passive mode. So no active pre-amp. [/quote]if it is not active it is not a Preamp

I have just done a plot of the cone excursion of a well known, well loved driver the Eminence Kappalite 3012HO. The box is 50L and the tuning frequency is 50Hz The power is 400 watts, the stated power of the 3012HO. The red line is Xmax, the maximum excursion at which the voice coil is under the influence of the magnet. It is not dangerous to exceed XMax by a small amount. However the Xlim or XDamage (12.5mm) , the point at which the voice coil is in danger, is exceed at 36.7Hz, 5 Hz above low B on a 5 string. Indeed you have to reduce the power at 31Hz to under 200W to avoid exceeding XDamage. [url="https://flic.kr/p/R8Gr7e"][/url][url="https://flic.kr/p/R8Gr7e"]Kappalite3012HO Cone excursion 400W[/url] by [url="https://www.flickr.com/photos/149986878@N08/"]chienmortbb[/url], on Flickr

[quote name='karlfer' timestamp='1481735579' post='3194712'] Anybody use foam underneath an amp head? Like many I normally use trusty Halford's car dash non slip matting to keep a micro amp in place. I've noticed that my LM 800 seems to bounce a bit more than most (whadya mean turn it down ) Anyway, I got to thinking, long term, that amount of vibration can't do it much good. So, I'm thinking of getting some 1/8 inch foam and cutting it down to just more than the area covered by the feet of the head. Daft? Worrying about nowt? Thoughts folks? Cheers, Karl. [/quote]If your amp is bouncing that much, is it possible you need to replace the cabinet?

I have the Fly. It is not loud but it is handy and light. I think it need the extension cab to be honest.

If you are reasonably good at woodwork the the 1x12 Basschat design is hard to beat at sub £150. The TKS cabs give a nice "old skool" sound and some of BFM's plans make nice speakers but are a little complex if your woodworking skills are basic. Or you could wait until the new year and see whether Santa leaves an updated Basschat design or two.

Got a reminder email just now. It said early bird discounts end at midnight. Went to book tickets and Earlybird sales had ended. Probably won't go now. It is probably really well organised but for me it is 100% cods up to date.

I thought they had "tamed" it on the later ones, must have been extremely "hot" if the pad on the mixer could not tame it though.

[quote name='taunton-hobbit' timestamp='1480714339' post='3186735'] ..........valve watts have more 'heft' ? ,,,,,,,,,,,, oops [/quote]No they just need more heft to move them. Now let's see who gets trolled more!

[quote name='Balcro' timestamp='1482069883' post='3197339'] I think I can see an additional function here for my cheapo but worthy Behringer BEQ-700 graphic equalizer (A Boss GEB-7 clone) . I bought it last Christmas for the fun of it and hovered back & forth for days between it and the Caline CP-24 (a clone of MXR 108 10 band equaliser). In the current discussion I would have been better off buying the Caline (circa £30), but since I only play in "the den" I saved about £12. The Behringer and the Boss have a cut & boost slider centred on 50Hz. With full cut, that will take out some of the electronic low level nasties between 40-60Hz and will probably make for a crisper sound without sounding tonally much different. The MXR and the Caline have 31.25Hz (that 0.25 of Hz is so important) slider, so at full-cut will possibly remove 10-12 dB of electronic & acoustic rumble between 20 & 40Hz. That's much more effective and a possible speaker saver. It would also seem to make sense if the equaliser were first in the pedal or rack-mount chain. Clean-in, clean out. That's all good but there may be more. After searching on "Microthumpinator" and "Fdeck" I read (in the other place) an interesting observation from a Mike Arnopol - "Put in the HPF (High Pass Filter) and dialed it up at the highest setting. The clack was gone. As I expected, but so was the low bass. Kept dialing it down. I wasn't a whole lot past the lowest setting when I didn't really notice the missing bass. But no more voice coil smack. The interesting thing---the C8 actually got LOUDER. I think it was because I was no longer using my amp's recources amplifying crap I didn't want to amplify anyways. The C8 as well as the 88 go substantially louder with the HPF. Substantially louder." PS. Search for "Behringer" directs you to "music-group.com", but click on the links & Norton Security pops up with a warning of an unsafe site!! The detail indicates there's a Trojan in the "downloads" section?! [/quote]Mike knows a thing or two about speakers and he is right about the HPF. That is why I prefer a variable and switchable one. Mike's describes just why an HPF is important and it has the added benefit of protecting the speaker and probably reducing power compression.

The canoe remark was a bit off but you do need a very steep cutoff to avoid cutting wanted frequencies. In my opinion at least 18dB per octave and I prefer 24dB from about 35Hz. If you play a 5 you may want to go to 30 but for most useable bass speakers there is little output that low anyway.

[quote name='sratas' timestamp='1482059210' post='3197225'] Markbass uses a HPF in its line of amps, a gentle slope if 6 db/octave at a frequency well below 40 hz...the vast majority of manufacturers use HPFs, some don't. I'm not sure, but I guess some old fashioned tube amp may not use it, think about svt, bassman of old, maybe even contemporary [/quote]6dB per octave below 40 Hz is as much use as a trap door in a canoe. As for the old (thermionic) valve amps, the output transformer cost and size rises almost exponentially with low frequency response. The transformer itself will limit low frequency output, and the inherent compression of a valve output stage will also help. As for a previous comment about guitar speakers, this has almost become thing of the past as the old 25W speakers used in the 60s have been replaced by higher powered speakers. I could build a shed from the chassis log Goodmans, Celestion, Fane and Jenson speakers I have replaced in my early days as a guitard.

My old Peavey P bass copy is plywood and it is why I was eventually convinced that the wood of the body does not affect the tone much (hardly at all). The Peavey has a great necl and I was gong to build a new body but I might try this instead.

[quote name='Myth_103' timestamp='1481919110' post='3196352'] The cloth itself moves when I play a low B. I'm pretty sure it's the cloth moving against the wooden frame that's making the noise. I'm using Mojotone's "Mojoweave" grill cloth. People build their grill cloth frames where the only place touching is just on the outside edges (1/8" ish strips around the front edges)? I supposed that may eliminate buzzing against the frame, but wouldn't it be more prone to loosening over time this way? [/quote]you could also try refitting the cloth after warming it with a hairdryer first. As it closed it will tighten on the frame.

[quote name='Downdown' timestamp='1481918748' post='3196349'] Fair enough, but without going into the techie stuff, is it a real problem with ported cabs and if so why are there no warnings about it in the manuals - or have I missed them over the years? Perhaps only some cabs are susceptible, but even so, I'd have thought that the ones that are would have a pretty clear warranty disclaimer in their manuals, as they do regarding power handling limits. I doubt I could return a cab under warranty if I'd blown a driver with too much power so why should blowing one by driving with too-low frequencies be any different? [/quote]The problem is there are many problems associated with the super low frequencies. Phil has outlined the most extreme. That is where the speaker/cabinet combination is no longer under the control of the amplifier. It may be only in very extreme conditions that this is a real problem but it is a problem nonetheless. The other issues are, subsonics that steal you amplifier headroom, and a room boominess that you cannot dial out with EQ (although neither of these (except maybe excessive use of EQ) are damaging to the speaker).

[quote name='Bill Fitzmaurice' timestamp='1481925481' post='3196418'] For you to approach xlim with most drivers they'd sound really bad. It's ignoring the warnings of impending doom that often result in it. [/quote]Bill at some gig volumes the death clank of the voice coil is lost amongst the general cacophony.

[quote name='Passinwind' timestamp='1481902298' post='3196148'] Yep. And as usual, there's no free lunch. [/quote]Designing speaker cabinets is what I call squeezing a balloon. You squeeze out something you don't want and something else squeezes out somewhere else. Charlie (passinwind) has designed an HPF and we have had many happy hours emailing back and forth about it. The real issue with speakers like anything else in life is that whatever you do, the laws of physics apply. Any designer or manufacturer that says otherwise is either kidding himself, you or having his balloons squeezed by the Marketing department. As for the HPFs built into most amps, they are not right for bass. Most PA amps have the HPF set too high and the HPF needs to have a very sharp slope to avoid affecting your bottom end. Let hope everything we open this Christmas is not like this thread (a can of worms).

[quote name='Basszilla' timestamp='1481799755' post='3195205'] Yes I use a very thick slice of foam under my Matamp gt200. All valve so I use that and then power it via a power conditioner. The vibrations hammer the power valves over time so it's best practice for me 👌 [/quote]why do you need a power conditioner?

That spec sounds like the ICEPoweer ASC 700 module is used. To get the most out of any Class D amp you need god heat management, that means weight. 3.5KG sounds like they have done it properly.