alexclaber

[quote name='skychaserhigh' timestamp='1368177734' post='2074049']If you want to hear your bass totally uncoloured , don't plug it in ![/quote] That's how I play my bass at home and how I test any new bass before I plug it in - if it sounds good unplugged then it will sound good plugged in as long as the pickups are decent. And if the pickups aren't decent they're pretty cheap and easy to change. My big rig is an Avalon U5 into a QSC PLX into a Big Twin T. That's about as low colouration as is possible this side of very very expensive large studio monitors. Tells everyone when you're playing well - and not so well...

[quote name='LawrenceH' timestamp='1368115315' post='2073416']...it's hard to see clear oscillations at 40-100 cycles a second with the naked eye![/quote] That's absolutely true. I've noticed huge cone movement when using a passive bass with a DC coupled preamp (Avalon U5) into a QSC PLX with all the filtering turned off (there's still a 5Hz filter) and that all very low frequency movement. Switch the 30Hz filter on and the movement drops drastically with no change in tone at lower SPL. Switch the 50Hz filter on and the movement drops further but the tone also changes somewhat.

[quote name='51m0n' timestamp='1368113564' post='2073393'] Markbass cones (at least in their big 410s) move a huge amount, they are flapping in the breeze. My ae410 cones hardly move at all in comparison. Yes I've watched the two closely one after the other, its not an optical illusion. No I cant explain it either, but I would bet an sfx thumpinator would sort that out, and have wondered in the past whether there isnt a similar filter built into Jim's crossovers....[/quote] My gut feeling is that it's a combination of tuning frequency and T/S specs but mostly the former. If cones are moving a lot more (like when you play a Big Twin next to a Super Twelve) then you should expect a whole load more deep bottom end and if you're not getting that then that cone movement has to be happening below the tuning frequency and being cancelled by the out of phase port output. You can't practically do passive highpass filtering at frequencies that low - the components would be ridiculously huge, heavy and expensive and the impedance curve of a woofer in a port cab is all over the place that low down so the filter wouldn't work without adding impedance correction components, which themselves would be ridiculously huge, heavy and expensive. Just to do a second order highpass at 40Hz assuming the impedance was flat (and not varying between about 6 ohms and 60 ohms across less than half an octave) you'd need a 50mH inductor weighing about 12lbs plus a 300uF capacitor. (Beaten to it!)

[quote name='machinehead' timestamp='1368099541' post='2073127']One thing I've noticed on all the Markbass cabs I've owned is that the speakers appear to have massive movement on the x axis, but then again, that might be an illusion caused by the orange colour.[/quote] I'm pretty certain that's the visual effect of the orange cone! Also cabs that are tuned too high cause the speakers to move a lot more and that's not always linear movement, so that may or may not be having an effect... You can do a lot by changing the soft parts (i.e. the bits that move) and do that with relatively small production volumes but you're always going to hit similar limitations to those of the original model (i.e. thermal and mechanical power handling). So tone can be changed a lot, absolute performance not so much. We've been working on custom drivers for over two years now and I think it says a lot about the quality of our current drivers and what we've managed to get from them that we haven't brought anything new to market yet!

[quote name='RandomBass' timestamp='1368092315' post='2073008'] I love that variable rear port design.[/quote] I'm actually planning something like that on the guitar cabs...

[quote name='Alec' timestamp='1367328373' post='2064233']A quick spec comparison: weight h x w x d (cm) sensitivity price (BassDirect) Genz Benz NX2 212T 23kg 79 x 54 x 42 101dB 1w/m £719 Bergantino CN-212 20kg 79 x 46 x 38 104dB 1w/m £950[/quote] Sensitivity specs are usually at best hopeful (on-axis either at a certain frequency peak or averaged over a certain bandwidth rather than pistonic or with weighting for power demands) and at the worst complete fabrications. I'd say these are the former and are probably done in a similar way (which matches how Eminence spec their drivers). However, what really matters is that the Genz sensitivity is for 1W (2V into a 4 ohm load) whilst the Bergantino is for 2W (2.83V into a 4 ohm). Corrected for equal power both cabs are 101dB @ 1W 1m.

I wouldn't buy anything or even bother testing anything until you have your new cab. Gig it with the Hartke, then you'll actually have an accurate idea of what works and what can be improved and we can help advise you on the stuff to try.

The Genz limiter light comes on a long time before the amp actually clips - there's another 6dB of input before that happens. If you want an all-valve sound without the weight, try to find a Warwick Quadruplet preamp. This has a tiny valve power amp and output transformer running a dummy load, and then a low current signal is taken from that to the preamp's output. They did heads too, which used the same preamp and then had a powerful solidstate power stage. I think there are some other designs like this but I can't think of them off the top of my head.

[quote name='discreet' timestamp='1365770502' post='2044219']If they're SS and not all-tube amps then yes, as long as you keep the master level at zero.[/quote] It doesn't matter where the master level is, amplifiers with a solidstate output stage are not bothered in the least by being used without a speaker connected. In fact, if there's a headphone socket on a bass amp it's usually just tapped off the power amp output with some resistors to bring the level down. If you own an all-valve amp, you'll know about it - it'll be heavy, expensive and contain a lot of glass! The only exceptions are the very rare solidstate power amps with output transformers - I don't know of any bass amp with one, although the Hellborg power amps have them and the likes of McIntosh power amps had them in the '70s.

It is too much continuous power that causes thermal death to speakers. It doesn't matter whether the waveform is perfectly clean or fully clipped, all that matters is the average longterm power and how long that's applied for (the longer the time, the less power it takes to reach thermal death, the shorter the time the more power it takes because the speaker has thermal mass which can absorb excess heat before the rate of heat dissipation becomes the determining factor). However, as the crest factor of typical music is about 14dB (1:25 average:peak power ratio), it's very hard to reach that continuous average power level without clipping an amp, unless what you're putting into it is very compressed or the amp is much more powerful than the loudspeaker's thermal rating.

FYI since largo's cabs we've switched to substantially harder ply and changed how we apply the finish, so it's harder from the moment it's dry. We've also found that however the finish is applied, it is much much harder after a few months than when it's brand new - it's almost like concrete once the cab is old. I'd be interested to see how a recent cab stands up to largo's use - I think it would shrug it off without any problem. The feet however are a niggling point that we're still working on - the latest ply holds a thread much better so they're much harder to knock off but it's still not impossible. We could use t-nuts and bolts on the big cab feet - we'll do some loading tests to see what happens if a cab is dropped from a height diagonally onto a foot (at the moment the screw pulls out, preventing enclosure damage). We'll also see if we can go a screw size larger on the small feet, that should make a useful difference. If a foot screw does strip its thread plugging the hole with a matchstick will make it as good as new, it's one of those 'bodges' that really works. I'd expect any touring band with roadies to flightcase a cab, just like they do with every other bit of the backline - the upsides with our cabs being the total flightcase weight being much lower, the total flightcase size for the max output being much smaller (which matters with the cost of transport nowadays) and obviously the sound being better than generic cabs!

[quote name='lobematt' timestamp='1361220112' post='1983109']As I said earlier I'm pretty clueless when it comes to techy amp stuff so that's why I'm asking here if it would blow cabs not rated at 1000W.[/quote] No, only if you turn it up very loud and ignore the audible warning signs from the cab (i.e. excessive growling, farting etc). And it's only 1000W into a 4 ohm load - into an 8 ohm load it's 500W.

You're right, it is - doh! Changing that now... Thanks!

Just for clarification, there is no longer a neo surcharge on our cabs - the neo price is still high but relatively stable so when we revised our prices (in January 2013) we removed the variable surcharge.

If I didn't have to move it (or pay for it or look at it ) then I'd like one of these: http://www.meyersound.com/products/concertseries/mts-4a/ otherwise a Big Twin T will do the job! Or a '69er for when I'm feeling like something different...

[quote name='neptunehealer' timestamp='1358439800' post='1939208']Going by watts, the Aguilar's are only offering 50 watts more in power combined arn't they? or am i missing something?[/quote] Yes, it's the volume displacement that matters (i.e. how much air the cab can move) not the thermal power handling. The thermal handling only tells you what it takes to kill them - what's important is how loud the cab goes before it starts to sound bad and the power handling rating doesn't tell you that.

[quote name='stingrayPete1977' timestamp='1356782836' post='1913496']There must be a point though where you need a big enough amp to drive them though?[/quote] Nope, the more speakers you have, the less amp you need. It's not the speakers you're 'driving', it's the air in the venue that you're 'driving' and the more speaker area you have, the easier it is to generate the sound pressure level you need in the room. [quote name='stingrayPete1977' timestamp='1356782836' post='1913496']Hanging 4 4x10s off an old Trace 150 watt head for example cant be the best can it, especially if your sucking up juice with a 5 string?[/quote] If they could handle the power (which they can't, an old Trace 4x10" only handles about 100W before distorting), then you'd need 300W to drive two 4x10"s or 600W to drive one 4x10" to the same max SPL as 150W driving four 4x10"s. In reality it's even more extreme than that because your cabs exhibit thermal and mechanical compression when you push them even vaguely hard, so you'd probably only need a 50W amp to get the four 4x10" rig up to the same SPL as if you used 600W into one 4x10" and it could handle that power without distortion. But power is cheap and moving big rigs gets tiresome.

We're back and working through the pile of emails! The Super Twelve and Midget don't use 3012LF drivers, they use 3012HO. The recommended amp power for the Super Twelve is 150-1200W. This takes into account the typical usage of the cab, the sensitivity of the cab, the thermal power handling of the drivers, the mechanical power handling of the drivers and what's going on in the real world in terms of signal content, duty cycle and actual power output of amplifiers.

[quote name='LawrenceH' timestamp='1355401158' post='1897837']Just thinking out loud, it might be easier to reconcile reports of the low audibility of mid-range/treble effects with data like Alex's by considering that a lot of the changes would be at frequencies dominated by non-pistonic effects. Many drivers in-cab will be crossed below this point so raw driver response is not so relevant, also PA and definitely bass cab drivers are often asked to work higher than ideal for crossing, so manufacturers work more on fine-tuning behaviour higher up for these via more complex cone behaviour...[/quote] The list of bass cabs where the woofers have any kind of crossover on them is quite a short one (Baer, Audiokinesis, some Barefaced, some Bergantino, anything else?) - the vast majority are running full-range. If we could run all our woofers full-range and get the performance we want then I would - big inductors are annoying components whilst passive crossovers and hot voice coils aren't the best combination.

If anyone doubts that speakers change a lot due to mechanical parameters shifting, notice how different your car stereo sounds when you've just de-iced the car compared to half an hour into the journey with the heaters on full blast. There's a big change in bass response! I wonder how well boot-mounted subwoofers work in the winter (mind is in the rear footwell!)?

Both drivers were fresh, they're handmade samples - to quote the transducer designer we've been working with: "The first samples were measured when it was about 18 deg C outside; the second ones at 8-9 deg C. Things stiffen up a bit from lower temps and always give you a touch more extension on the top end. They’re built with the same parts, though…" But it shows that it's not as simple as anyone claims! I remember an incident on talkbass when someone was arguing about something tone related regarding bass cabs - it went on for a while and his opinion seemed like it should carry some weight, seeing as he was an experienced professional bassist. Then he mentioned that his hearing was completely screwed, to the point that even his hearing aids in it was way off how it had been in his youth, due to years of high SPL damage. He didn't seem to get the irony that he was being very forceful with his opinions on how something sounded yet he didn't have the sensory perception to analyse the sound accurately - like if I commented on David Hockney's massive recent exhibition without my glasses on.

Adee, I agree. Everyone gets responded to eventually, it's pretty unusual for someone to have to wait this long or send so many messages before they receive a reply - it's probably because I almost never manage to clear out the backlog of emails in the 'to reply to' list and I don't go through them in chronological order, I prioritise them as best I can, so occasionally one person can end up repeatedly missing out on being in a batch of emails I've dealt with. If Frank had emailed saying 'I need my cab for xxx on yyy date then it would have come higher up the priority list, likewise if he'd paid in full and was concerned that we'd run away with his money, etc etc. We do have a telephone here too which usually gets answered during working hours.

When I have some time and the weather is better I'll get some measurements of fresh vs broken-in woofers. I know I've heard the change very obviously and I know hundreds of customers have heard it too. As I've said previously, it isn't just the low frequency response that changes due to the shift in T/S parameters, it's also the midrange and treble response. If you've been involved in the design of cones, dustcaps and suspension then you'd know that seemingly tiny changes can make big differences in tone. The attached plots are the same driver, the first measured in the summer, the second measured in the winter - ignore the LF stuff because it wasn't set up for that, it's a midrange/treble response measurement. The lower temperature changes the cone and the suspension stiffness - and look what that does to the frequency response curve!

Just replied to your email, it's amongst the large pile I've been working my way through. I'm not sure what you're paranoid about, we only have your deposit and that would barely pay for the crossover components?!! We've been waiting on the woofers for an age after our supplier completely screwed up. PMs through here usually get seen and then forgotten if I don't reply immediately, emails very rarely get forgotten (they get labelled into various lists) but often end up in a large queue and as we've been messed around for weeks and weeks by our main supplier I've been holding off replying to those waiting for Big Series cabs until I actually know the score. They've been a textbook example of how centralising distribution through removing satellite warehouses can be a hopeless mess during the transitional period (this past year) when your computer systems and thus stockflow predictions are not fully integrated. And we and thus you have borne the brunt of it, though at least they're paying for their mistake by having to airfreight product to us (v expensive with speakers because of the magnetic issues).

The old EA CXL112 is an 8 ohm nominal cab with a 4 ohm nominal woofer. I heard it explained as that once the voice coil is up to playing temperature it's then measuring more like an 8 ohm woofer, though that doesn't help if your amp shuts down before that point...