alexclaber

[quote name='ficelles' post='1322644' date='Jul 31 2011, 11:41 PM']Lets the air out.[/quote] And why would you want that to happen? Just curious about the thinking - I think I might write an article about ports soon...

I've heard good things about the SVT driving a Super Twelve, despite my scepticism about valve amps! Replacing an Ampeg 410HLF, to quote "I gigged with it last night and have to say it sounded amazing! such a fat, warm, punchy and crystal clear sound, my SVT has never sounded so good". And following another gig, "I gigged with the 2x12 last night and have to say I am well impressed with the sound, wasn't expecting so much warmth from a a pair 12's in a cab so light. I've played at this venue many times with various cabs, in fact I played there last week with my Ampeg 410, so I've got a good basis for comparison, your cab sounded tighter and more focussed, bags of bottom end & punch. I noticed that my amp volume was quite a bit lower than usual too, this cab is loud!" I think what I said about your Bassman was that it wouldn't be loud enough for the gigs you described although I may have overlooked how dirty a sound you like - the more overdrive you like, the less power you need. However that restriction is pretty much common to all similar sized cabs, that's why valve amps are often found on BIG cabs!

Venereal disease, Very bad, eFfing big, Evil *astard Ports, Quite Techy Considerations. HTH.

They're all tuned in the sense of having a resonant frequency, the port length is just determined by the port shape and baffle thickness and thus the wodge of air that thus resonates on the air spring of the enclosure - same as the soundhole on a classical guitar. Only work well when Vd is low, Vb is high and Fb is meant to be high.

You can put an XLR attenuator inline with the DI if it's too hot - my old Peavey had this problem. It's worse with cheaper desks as they expect the XLR ins to be mic level but many active DIs are instrument line level and some are pro line level (even hotter!)

If everyone was good at thinking for themselves then I'd never have to say anything and all those strange guitar shop myths would never have proliferated. Nevertheless I shall continue to hope for that utopia!

[quote name='Teddy_Hitch' post='1315641' date='Jul 25 2011, 12:46 PM']...I moved on to an SVT7-PRO... ...the level coming out of the head was still not too loud...[/quote] One of the risks of comparing amps in a shop is that many bassists will turn an amp up to 2/10 or 9 o'clock on the volume knob and compare how loud that is to their current amp (or some of the other amps in the shop) with the volume knob in the same position. Unfortunately that doesn't tell you anything about how powerful the amp. Every old Trace Elliot amp I've come across sounds incredibly loud with volume knob in that position but you can't turn it much more without it distorting, whilst the old Euphonic Audio amps would sound very quiet at 9 o'clock but you could turn them up to past 3 o'clock before they distorted, by which point they were (unsurprisingly) louder than lower rated TE amps! Just something to bear in mind when amp shopping. A comparable thing with cars would be how hard a car accelerates in a given gear with the accelerator pressed down a certain amount - the accelerator linkage and interface with the engine electronics has far more bearing on how fast the acceleration is than the power:weight ratio of the car. Only full power (throttle fully open) testing will tell you which car is quickest! I suppose another way to look at it would be like saying that a Suzuki Liana is quicker than a Ferrari 458 because you saw the former overtake the latter on the motorway once... I don't think the Hartke LH and Orange Terror preamps are similar in any way - the former has a topology with tons of headroom and the latter doesn't!

Bubblewrap only works in addition to double layers of cardboard and I'd still want more protection at the corners. You want two layers of good corrugated cardboard everywhere (either double-boxed or a box with cardboard offcuts in between cab and box, plus extra protection at the corners - we use quite hard expanded polystyrene comers but a DIY approach is to make packing corners out of corrugated cardboard with a bit of origami. Assume that it'll get dropped out of the back of a truck and pack it so it can survive that! It's not so much that the couriers 'want' to chuck stuff around, it's just the normal mode of behaviour - you should see all these parcels labelled 'fragile' getting tossed to the back of the FedEx van to clear space when our parcels are collected...

Home practice = 60-70dB Gig = 105-125dB If you want your gig tone at home levels you'll have to twist quite a few knobs!

Depends on the amp! A surprisingly large number aren't phantom power safe... What does the manual say?

I recommended an S12T originally. I'm not 100% convinced a Compact will be perfect but I'm 100% certain it has a better chance of doing the job than all but the Neox-212T, which itself is much more like an S12T with less potent drivers.

If you bring it to our workshop I can test it and give you an answer in about 10 seconds!

[quote name='Prime_BASS' post='1307137' date='Jul 17 2011, 09:59 PM']With the right EQing a 15 will sound more "rounder" than any 210. Take a look at the Barefaced website. I've done a fair bit of looking but you'll be hard pressed to find any 210s that go as low and as loud as even quality 1x12 let alone a 1x15.[/quote] I don't believe I've ever said that about 1x15"s. In fact I've never given damn about speaker size (apart from in polar response considerations, but side-by-side smaller drivers are worse than single or vertically aligned larger drivers). There are numerous parameters that matter to me and speaker size is way down the priority scale. And the 15"s used in bass cabs over the years have tended to be worse in the parameters that matter than the popular 10"s over the years, usually because manufacturers didn't seem to consider that you should pay more for a 15" than a 10" because like for like it does twice the work. I've used 2x10"s that beat many 15"s and 12"s. And the reverse. Trying to tell the the bass world that speaker size is the least of their concerns sometimes feels like trying to tell 1950s America that skin colour has no bearing on your ability to be a good President. It might have taken the world decades to get beyond looking at someone and not making a mindless judgement based on what colour they are and instead listen to what they have to say but so many bassists are still determined to hang onto groundless old ideas and make blanket judgements based on looks instead of listening with an open mind. Jonathan Swift wrote a good book addressing bass players' ill-informed prejudices about big speakers and little speakers back in 1727 - unfortunately some editor changed it to being about very small people fighting over whether to cut the 10" end or the 15" end off their soft-boiled egg, and the original manuscript is long lost...

I'd take both. Small venue = small stage = bassist standing so close to a single small cab on the floor that only his knees can hear it.

[quote name='dc2009' post='1306765' date='Jul 17 2011, 03:54 PM']Out of interest, what would you say (based on your opinion and experience) is the head that works best with your gear?[/quote] Hard question to answer! Depends very much on the tone you're after, the bass/strings you're using, the loudness of your band and the specific cab. They're aren't many amps that won't work well for someone with one of our cabs. I was going to write a shortlist of amps that are popular with our customers but I keep thinking of more and more models!

Stevie, if you enlarge the hole between the long ports and the main enclosure it would become a conventional ported box. If you blocked that hole it would indeed become a TL. But the fact that that hole acts as a second port changes everything! It's quite a fine detail though, had to read the patent to see it...

Aha!

I'm not convinced by that. What happens if you turn the driver around? Then it looks just like a bass reflex cab! The only difference I can see between cone-inwards and cone-outwards mounting is that the latter gains you fractional extra internal volume and the woodwork required for rear mass-loading (via the hole it fires through adding air mass to the cone as on the Omni15) is a bit easier. Now if the cab was designed to be mounted in a wall so that the back of the driver is an a different room to the listening room then that would make it a different sort of cab but that doesn't appear to be the case.

It's complicated but the main risk is heat. The other risks are related to voltages and currents inside the transistors but all these failure modes are related to voltages or currents being too high, so regardless of how the transistor fails it will only happen when you have things turned up loud.

Jack...

At home SPL you'll be fine using your amp (assuming the low impedance protection doesn't kick in) just don't turn it up loud! The minimum impedance restriction on amps is due to current capacity - only ask for 1% of its power output (which will still be loud at home) and you're only asking for 2% of its current capacity.

It isn't the speaker size that restricts what a bass cab can handle, it's the volume displacement (Vd). Vd is the product of cone area (Sd) and undistorted cone excursion (Xmax). Doubling Xmax means you can put out as much bass output as a speaker ~2 sizes bigger - so 8" matches 12", 10" matches 15", 12" matches 18". (Or 1x10" matches 2x10", 1x12" matches 2x12" etc...) However Xmax rarely comes cheap! One giveaway for how much bottom a ported cab can produce is the port area (because high Vd speakers move so much air). Of course you could put a big port on a cab with a feeble speaker but that really wouldn't be cricket! The only way to truly know what a cab can do is to use it in a typically loud rehearsal or gig! So much depends on the tone you like and how your drummer plays. (I've got rather good at predicting this based on answers to numerous questions but it isn't an easy job and you have to understand all parts of the puzzle). Hopefully you'll be ok!

Stevei, tsn't a reflex cab a Helmholtz resonator? Though I see your point, you're suggesting that the cab works by solely exciting the resonant system of the two masses of air in the ports vibrating against the spring that is the volume of air in the enclosure divided by the area of the port:enclosure opening. But what's happening with the woofer backwave, why wouldn't that act like the frontwave from a woofer in a normal ported design? Guildbass, interesting stuff about the bass! Did you compare how the output varied depending upon pickup choice and plucking position? That has a significant effect based on my studies. I'm going to be doing some research into this and writing some articles for BGM in the near future. Your comments on getting a speaker to reproduce those low fundamentals are about halfway there! The reason most bass cabs have that ~100Hz bump is due to the cabs being too small for the driver's Vas. You don't need a very big driver to move air at those low fundamentals - you need a driver with very high volume displacement, which is a function of cone area and clean cone excursion. Obviously increasing the driver size increases one of those parameters - but in the process it also increases Vas which makes it harder to get deep response from a cab without it ending up impractically large. A speaker port doesn't work like an organ pipe (a transmission line speaker does) but it does indeed work like blowing over a bottle. However if you put two speaker ports into one enclosure you don't get two independent tuning frequencies, you get one whose frequency is the function of the total port area, enclosure volume, and total port air mass. I haven't come across a problem with most modern amps driving speakers that can go low - apart from valve amps which really do struggle - but most modern amps are seriously powerful! Regarding the output from a double bass, I believe it essentially works like a dipole speaker (thus there's a lowpass filter effect which depends upon the frontal area of the body) plus a Helmholtz resonator whose tuning is set by the F-hole areas and body's internal volume. Although I've yet to measure one, from what I've heard in person and based on other stuff I've read I doubt there is very little low fundamental content in the radiated acoustic sound. An electric upright would be another animal entirely.

I really rate GK's heavier heads - however I'd be very unlikely to recommend one to someone that likes very clean heads like Markbass. They have a very cool output stage with tons of current capacity and really nice behaviour on the limit due to the way the power amp overdrives - but if you don't like growl and grind from your amp head you won't like that. The preamps' 'flat' EQ curve is quite rolled off in the lows and boosted in the highs, so compared to a Markbass with the same knob settings it'll sound thinner and brighter. Crank up the lows and revel in the growl and the 700RBII and 1001RBII are some of the loudest heads on the market and will stomp all over most of the superlight heads (and it'll take a good cab to handle everything they can give). If you want smooth and clean though you will be seriously underwhelmed...

Apologies for the lip synching... This is what slap bass is for and how to do it right. Of course that's just in my humble opinion: No, actually it isn't, it's FACT! Do enjoy the bass break three minutes in.