Phil Starr

Well Bill you might if you plan to play solo bass with all the treble rolled off, I suspect Joe intends to play with other musicians, noisy guitarists and such like. If he pushes the bass to those levels you can expect everyone else in the band to turn up to match him. That'll probably mean the band collectively are going to reach levels maybe 6dB above the sorts of levels we are describing. I'm talking about a capability of 40dB dynamic range with peaks of 120dB for each instrument. I don't think you are seriously suggesting safely going up to 160dB peaks. I've chosen to make a whole series of assumptions in my sound levels, without making it into a 101 acoustics paper I have tried to indicate which bits are factual and what my reasoning is based upon where I've made broad assumptions. I don't think they are anything more than one person's opinion offered as a guideline but they are based in real world experience. I'd absolutely say that a speaker capable of 120dB across a broad spectrum is going to match a drummer 90% of the time and one which will only do 117dB is likely to struggle at times in some bands. I'm trying to keep it simple too, there are so many variables. The only point I was really making is that there is no point in just purchasing more and more sound output just because you can, and that there are hazards in extremely high sound levels. There comes a point where you are loud enough.

It's slightly complicated with two cabs because the impedance changes so you may, or may not draw more power from the amp. That's probably less of a problem with valve amps of course as the output transformer means they should be able to match to most common impedances. For the same power doubling the cone area will give you an extra 3dB. That's how itsmedunc got such a good result from his Ashdown 4x8's I'm guessing here but an 8" speaker is pretty efficient if it gives 92dB/W. Two would give you 95dB about the same as a reasonable 12" speaker. Four drivers would double again so 98dB/W and two cabs 101dB/W a 50W amp into this would give an extra 17dB That will give you 118dB the same as you might get from a Two10 and a 100W valve amp. Two Two10's with a 100W amp would give you 121dB, with a little overdrive/distortion that would be as loud as a 124dB solid state system in practice. Louder than almost all drums and more than enough to permanently damage your hearing. At this stage I need to say something. Each 3db increase in level halves the time you should be exposed to noise. Anything above 85dB will damage your hearing permanently if you are exposed to it for too long. The 100dB levels we average on stage with a Rock band will start to damage your hearing in about 15mins without ear plugs. I have mild tinnitus. https://www.noisehelp.com/noise-dose.html

That's spot on. To avoid having to dig the log tables out as a ready reckoner all you need to know is that 10x the watts is 10dB extra and 2x the watts is 3dB. You can then make a quick rough calculation by adding the extra dB's you get for the extra watts. Sticking with the Barefaced 2x10 which gives 98dB for 1W and looking at something like a 400W amp. That's two lots of 10x power and then two lots of doubling (400 is 10x10x2x2) in dB's that's 10+10+3+3 or an extra 26dB, 124 in total with the Barefaced cab. You can only just hear a 1dB change in level so calculating it to within a dB is usually good enough. A 300W amp is going to give between 1 and 2dB less 122-123db which is close enough for most purposes. The other bit of the story is why it's important. A metre away from a drumkit the average sound level is around 103dB. An audience makes an ambient noise level of 85dB or thereabouts so your quietest bass note needs to be at that level and your dynamic range (the difference between the quietest and loudest notes) will be about 40dB. You'll operate in a range of 80-120dB in most circumstances and if your system will do this without distorting you are going to be able to cope with most situations. When looking at bass systems I always look to beat 120dB as a target. With a valve amp you can crank it up 3dB and it will distort, in the example above the distortion kicks in at 118dB, but because its a valve amp you will only notice it as a bit of grit on the very loudest notes and a lower power amp amp will still deliver.

I'd say the sweet spot for valve amps is around the 100W mark. Any more than that and they get pretty heavy, and expensive. you can get away with a little less power with a valve amp because you can drive them up to their limits and the resulting overload is quite pleasing rather than unpleasantly distorted. Remember valve watts and solid state watts are still watts though, there's no magic going on just nicer distortion. Even that Barefaced isn't mega efficient compared with the old speakers that used to be used with valve amps 98dB/W will give 118dB with a 100w amp. My 1x12 gives 121db with a 300W amp and is just capable of matching a drumkit. That leaves you 3dB down though I think you should be able to push an extra 3dB higher on average because it's a valve amp. I suppose what I'm saying is it's very do-able but you won't have a lot to spare on a very loud stage. If you had a couple of 2x10's then you'd be sweet. Hope that helps

I really like the look of those beta's in the 50l cab and I love the mid peak in their response, it's a nice wide prominence showing a nice controlled cone break up rather than the much sharper peak that the Eminence Delta shows. It's not going to be a neutral sounding cab but it's pretty much the response I dial in on the graphic when I want the bass to cut through live.

Double the volume would be good but you'd need to recalculate the ports, they tune that particular volume of air irrespective of the number or size of the speaker. If you decide to go ahead I can calculate that for you or you can do it yourself with winISD a great piece of free software. I haven't looked at that Celestion, it doesn't have the excursion of the Beyma but that would matter a lot less in a 2x12. I know Stevie likes the look of that driver and I'd trust his judgement. I quite like the look of the Eminence Beta in the 50l cab but for me it works less well in the 30l cab.

That's right, we put in four ports because we had some concerns over port noises shifting that much air through only a couple of small ports. The mk2 cab has a single large port. We stuck to the small ports in this cab because you can cut the holes more easily by using a standard hole saw. I tried a slot port too but decided it was tricky to build because it needed clamping whilst the glue dried

Not so far, apart from the corner bracing inherent in the design. The panels are fairly small and that helps and a simple touch test shows them to be no worse than a lot of cabs. My intention is to go through the sort of systematic process with a signal generator that Stevie used on the Mk2 speakers but band shenanigans means that I'm spending more time herding cats than usual. (and also playing bass and learning new songs, so not all bad) I'm also planning a new cab building technique with more elaborate bracing which would be relatively simple for home builders and I might use this cab as a test bed for that technique. It's always down to time really.

Just thought I'd do a quick update on this topic. I haven't had much of a chance to use the cab in anger until the last couple of weeks down to the usual band politics and lack of gigs followed by all the work involved in starting a new project. You've probably all been there. Anyway I have had the chance to try it out in anger at a full rehearsal. As a little extra spice the drummer has a 7 week old baby and hasn't been out for a while so was hitting things with a little extra enthusiasm, thank heaven for earplugs! So, I was back in the hall with the most appalling acoustics, all hard surfaces high ceilings, well you name it. To save anyone having to go back the speaker was designed to cope with this sort of space, and those pubs where you just can't get the bass sound right. The deepest bass was rolled off with a 2dB hump at around 120Hz to add a bit of thump so they didn't sound too bass light, a kind of old school underdamped response but with a modern high excursion driver using a single 12 built into a very simple 30l cabinet. To complete the picture I was using a Fender American Deluxe P Bass with a Markbass Tube everything set flat with VPF set at about 10.00 o'clock. We play pop/rock covers AC/DC, Queen through to Chelsea Dagger via Summer of 69 sort of thing (I've no shame) It sounded awesome, first of all really effortlessly loud with two guitars a keyboard and drummer really driving on it was really well up in the mix, not a hint of a clipping light on the input and with plenty to play with at the master volume. I have to say there didn't appear to be much in the way of high power compression either, it was over 30degreees outside, warmer in and we played for three hours without any noticeable tail off in performance by the speaker. This with a single 12 in a cab the size of an old fashioned milk crate. The sound? Well it was the sound of a P bass, punchy but sitting just right in the mix once the band got going. Not the sort of thing you'd set up playing alone at home where you'd probably want a bit more deep and some mid scoop but with a band just spot on. I can also report that in this really difficult room I had no problem in monitoring my own playing both with and without ear plugs. I know you can't trust someone praising their own design but this was meant to be built as a bit of fun, a demo at the bass bash, something I wanted to try. I fully expected to be building a 45l cab which to my mind modelled a lot better but thought I'd try a cab just on the silly side of 'too small'. it was only when we plugged it in at the end of the bass bash I realised it was worth sticking with. It started life as a curiosity piece really but honestly I'd recommend building one to anyone who wants something really portable, isn't too bothered about the top end (it has no tweeter/horn) and who is happy with a straightforward old school sound straight out of the box. It will cost you around £120 to build and once the parts are cut, well it took me around an hour to do the basic build in the video, maybe 2.5 hours in total including the pre prep and finishing.

+1 for the Peavey IPR1600 I have two for PA use, they are just plug in and forget, no real sound of their own and they just work.

Oh that's interesting, I have a J Retro on my Jazz. I get lovely sounds at home and through headphones in particular but in noisy environments have had problems with not being able to pick out the bass. Swapping to a P the problem disappears and on days when I record the gig there is always plenty of sound out there from the J, I'm just not getting it. I've even wondered about going back to passive. The J retro has bass boost only so unless the bass is turned right down you can have a lot of bass boost without realising it. 3dB of boost is going to double the demand for power from your amp for a fairly subtle change in tone. I used to get some nice tones from the j-Retro with my old Hartke but with some strange shapes on the graphic. If you have a range of basses it might be worth investigating.

It might be sensible to contact Barefaced, or you could try a pm to Alex to get him to contribute here. If the difference is only 1dB you'd only notice the difference when switching between cabs in an A/B test. Having said that the broadband sensitivity doesn't tell you much, most of what we perceive as loudness is about the midrange sensitivity so a speaker with a flatter response may sound quieter. There's also the reality that in practice smaller speakers usually need more power to get the same volume of sound, whatever the advertising implies. A speaker may be very efficient compared with other speakers of it's type but a 1x12 is never going to be as efficient as an 8x10. Then you had your original speaker for a while and you'll have been tweaking the eq to get the best out of it, it'll be a while before you get to the same place with the new one. I really wouldn't worry about where the gain and master volume are set. So long as you could keep up with the drummer and the sound isn't distorting then your amp is happy, maybe this speaker just needs driving a little harder and that's OK. Obviously if it's distorting and the amp is overloading then that's a different issue but if your speaker gives you less gain then the amp will have to give a little more.

My greatest bugbear, apart from people who, when they do show up clearly haven't looked at what we are planning to rehearse. I understand people are busy and sometimes things come up which we can't control especially with young families but in the end if you can't rehearse you can't be in a band. If breaks between rehearsals get too great then you lose the advances you made last time and end up constantly rehearsing the same songs over and over. Most of us are just weekend warriors and family/relationships and work usually have to come first but then there are other priorities and being in a band is quite a commitment. For us music is a team sport and there has to be at least some sense of not letting the team/band down. I still play cricket from time to time and if I commit to playing on a Sat I know I am letting 21 other people down if I don't show, 21 people who have arranged their weekend and their families weekends around the game. If I fail to show or cancel at the last minute for a Tues rehearsal it's the same thing multiplied by the fact that four other people have spent the weekend finding time to practice/learn whatever we are going to rehearse. Generally it's the same people each time and what they are basically thinking is that their busy lives are more important than other people's busy lives. You can tell this is a recent experience Anyway, a couple of practical suggestions: In the end the only way I've ever known bands to work is to have a regular practice day. In the end there is always someone who cant do Mon, Tue, ….. or weekends. If you pick a day which suits the majority it is surprising how people rearrange if the alternative is leaving the band. Once you've settled on a day they'll book their pilates class another day and all will be fine, the band stop booking things in on a practice night because they know Tues is the day we all meet. Moveable days don't usually work as people forget and book something in, or their partners do. Bands work best IME when two people form an engine room driving the band. If you turn up and two people have been quietly working away together at new material it generally goes well. It's relatively easy to jam along if two people at least are solid, they'll end up sorting out chord sheets and the like and will generally pick up on most of the organisation and drive the band. If those core members get together maybe with a singer or guitarist as well it can be really productive. a random meeting of three musicians out of five less so. It takes organisation and a decent musical brain to isolate little bits of a set or song to work on, not three people who have all either not picked up their guitar or put the kit together in the intervening fortnight. Only 12 bar hell can emerge from that. If you are working with band members missing an acoustic workout sometimes goes well IME, sitting down where everyone can hear each other can really give you a different insight into songs and your role in them, and people get to talk when they aren't competing with a kit or a guitarist widdling away in the corner through a 4x12. Bitter, me????

Just as a general principle (though relevant to the Mackie Thump) you get what you pay for to a certain extent. More money buys a bigger magnet for the drive unit and in turn that means fewer compromises or more scope with the design. with a bigger magnet you can extend the magnetic field and have the bass controlled over longer excursion. If the magnet is limited you either have to shorten the magnetic field or spread it thinner and have less sound per watt. The Mackie does the second, it has 3db less output than the SRM450 it's 'big brother'. So a cheap PA driver is going to either be less efficient than a top range model or it will overload with a bass at relatively lower power. However for home use? Well unless you live in a stately home pretty much anything is going to be loud enough so volume probably isn't a big worry. The other consideration with a cheap FRFR/PA speaker is that it is likely to have a cheap plastic cabinet and these tend to resonate a bit if you play loud bass through them. I'm not recommending any particular model because I haven't tried a range of them but FWIW I play in a loud acoustic duo and after struggling with the acoustics in the pubs we tend to play in we decided to scrap the back line and just use floor monitors. These are Behringer B1320D's nothing special and bought because they were adequate for vocal monitors. They are working fine as bass monitors so far and we only use one for rehearsal. At home they sound pretty good with bass, guitar and two vocals, though we have to roll off the bass fairly hard because they have a built in bass bias. If it really is just for home use though I'd probably look for something more compact like a 10" PA speaker.

There's no standard for clipping lights so it would be hard to say how much clipping would be acceptable. Heed Bill's advice about tweeters/horns. If the amp is genuinely clipping all that extra power pretty much goes through the horns. Some clipping lights are on the input stages rather than monitoring the output. That makes it easy to set up a little distortion and then adjust your levels with the same level of 'grind' at all volume levels. If you have an input level control (sometimes called gain) and a master volume try turning the master volume right up and the input level down and see if the light goes out, or even turn the volume on your bass down and the master up. If that is the case your input stages were overloading and the amp actually wsn't giving you a little more power to play with. Worth a try anyway.

It's an interesting thought, as cabs get smaller the need for folded ports increases. I've tended to avoid them so far but this is a relatively pain free way of getting a result. Thanks

Just to be clear, the cheap QTX driver is the same one used in a lot of cheap cabs, mainly those advertised as 'party cabs' or disco cabs but also used as cheap and cheerful PA systems in churches and schools. Maplin used to sell them as their cheap as chips speakers. They are remarkably good for the money but I just wouldn't advise anyone to go out and buy one, they really aren't up to any serious bass use at any high power level, They might sound great for home practice, I couldn't say but for £135 you could probably buy an active PA speaker with amp tweeter and crossover built in but with the same driver. He's probably designed the cab for the Beta anyway. That's what I'd do and the cab will probably be tuned to around 50Hz. A 50l 50hz cab with a Beta will be fine and he's probably used winISD anyway. Here you go https://www.ebay.co.uk/itm/QTX-QX12A-12-ACTIVE-PA-SPEAKER-400W-DJ-DISCO-SOUND-SYSTEM-PA/202077424069?hash=item2f0cc0c9c5:g:O2YAAOSwls5Y63zR Bill will know better than me of who uses the Beta in their commercial cabs, they might be a similar price to these and they'd definitely be cheaper used. Nobody is ripping anyone off but there isn't a free lunch being offered either. There's a TC RS212 in the for sale section for £380, less than a pair of the Eminence driven cabs at £200ea, They'd probably be similar but I'd go for the brand name because I'm not bothered about stuff being new.

I'm amazed this thread is still running. This is a bass player trying to make a little money by building cabs. He's chosen the simplest of designs, a roughly 50l 1x12 and is offering effectively to put in the driver of your choice at different price points. You'll get exactly what you pay for. His advertising claims are no more silly than anyone else's, kind of true but not very enlightening. I'd suspect you'll get a very simple box which you could build yourself for £40 but someone else has put it together for you. That QTX driver is the sort of driver found in millions of cheap speakers with a hundred different brand names all coming out of a factory somewhere in China. It'll make a noise but won't have a lot of deep bass and will give up the ghost fairly early if you turn the power up due to over excursion. The Eminence Beta will sound like an Eminence Beta, it's a good mid range driver for bass and is used re-badged in a number of designs. An unbraced 3/4" ply cab that size isn't going to be high end but the panels are rigid enough not to be awful and you can always add braces yourself. I'm not as cynical as others, having done something similar back in the early 1970's. It's tough when you have no capital and you have to do everything yourself. You operate on the tightest of margins and keeping costs down by saving on handles and fittings and sticking to one design makes sense. I doubt he's making minimum wage once his time is factored in but we all start somewhere.

Well done for keeping going. It's always distracting when things like that go wrong but you can only control your own bit and getting on with that is the truly pro attitude, whatever gets said afterwards. Good to hear the Mk 1's got some approval too.

I've no quarrel with using the ports as handles. Ports do have their own resonances and putting them on the sides or backs means those resonances will be less audible, though whether that is a significant factor I doubt. It's quite a clever idea I suppose and it's rare to see anything novel, I haven't seen this before. The piezo tweeter is one of those cheap things that a lot of people switch out of their bass cabs, neither here nor there really, some people like them as giving a little more top. Basically this is someone trying to start a business building cabs and it's a pretty straightforward 12" cab fitted with an Eminence driver, the cheap one fitted with the Alpha isn't going to sound too great but the one with the Beta, well it's a nice driver at that price point and fitted to a lot of commercial cabs. You could buy a lot of used 112's for that but who knows you might have the next Barefaced

If it works then it is worth more than that, the only fly in the ointment might be if the transformers are bust, the output transformers are costly items to replace and that would detract considerably from their value. Mr Foxen who used to post here frequently but has gone quiet might be someone to contact as he did a lot of work on old valve amps. Everything else on these amps can be replaced fairly simply.

Bill is absolutely right, cabs on top of each other with the centres of the cones aligned is best. Anything else and you'll get places on stage where frequencies are cancelled due to the sound arriving from the two speakers at different times. However I'm not a purist about this. We rarely play in ideal conditions in the UK, lot's of small venues and misshaped buildings, and bands who are run on a shoestring budget with inadequate gear. Sometimes you have to improvise and then it is a question of balancing two evils. When I started doing PA a long time ago we often used to swap speakers in a stack so the bassist had one of the guitarists 4x12's in their stack and vice versa. On a wide stage that helped them hear each other. Some of the older rock bands still do this, probably out of habit but at least one band had that arrangement at Glastonbury this year. If the onstage gear is just for monitoring and what the audience hear is through a massive PA it wouldn't be a problem. In one difficult venue I had my amp facing the audience but added my practice amp (Hartke Kickback) as a monitor for the drummer. If you think about it some bands scrap backline altogether and use floor monitors, the bass might be coming out of all of them so you have set up all sorts of interference/cancellation problems. It works because you are much closer to your own monitor than the rest. That means it is louder than the rest so although there is interference from the other monitors in practice it isn't noticeable. So I'd say default position is vertically aligned cabs but if you are due on in 5 mins and someone really can't hear then be prepared to be creative, then go back and think how you can sort your monitoring after the gig. In our case we gave the drummer their own monitor at ear level and let them mix in what they wanted to hear, mainly vocals and bass.

Without wanting to start a major derail of this thread there are a lot of assertions here that are at least debatable. One thing however stick out as just being wrong, that rectangular vents give more "woof" and ducts are more hi-fi. Whilst the shape of the ports will change the port resonances and changing that shape will also alter the point at which turbulence sets in the idea that different shaped ports of the same length and cross sectional area will have vastly different sounds isn't something with any evidence or mathematical proof that I've seen. I'm interested in what you mean by Line Array. The first of what we currently consider line array systems appeared in PA systems in the 1990's. A series of identical cabs with the mid and high frequency drivers vertically aligned to control dispersion. The idea of 'line source' has been around a lot longer, single cabs with vertically aligned drivers. The original paper on that was published in the 1950's but the phenomenon was known a long time before that and I remember churches with line source speakers fitted probably back before WW2 plus designs published in old books before Olsen's paper. I can't think of anyone using Line Array for bass, though the Genzler Bass Array cabs look interesting.

Yes it's an old Sheffield unit and there were various versions rated 150W and 250W, there's also a recone kit advertised which is 8 ohm. There's a moderately lively second hand market for Peavey drivers so you could probably pick up a cheap replacement if something went wrong. Frankly you've not got a lot to lose, you could probably get away with using your Elf for quite a while with no problems. If you are going to use it at home it'll make a lot of noise. If you are going out and gigging with a loud rock band then it's probably not going to last too long and you'll want a better speaker fairly quickly anyway. Matching amps and speakers isn't an exact science anyway. Play your 150w amp with clean tones and you're probably only averaging less than 10w anyway so it isn't going to overheat the speaker. Play with distortion and a lot of bass boost and you can probably blow quite a few speakers rated well above the amplifier power by over excursion at the lowest frequencies

Yep there are arguments for and against putting the port on the back. The main argument for is that ports produce noises at mid frequencies due to all sorts of resonances, putting them round the back means the noises can't really be heard. Against is the thought that you can't ram the cab hard against a wall and potentially block the port, but even a few cm away it won't be a problem. With compact cabs it's always a bit of a problem fitting everything on the baffle without weakening the panel. The other solution might be a slot port, you'd have to form it in timber so there is extra woodwork but it's a nice tidy way of creating a port, another more complex method is that used by some manufacturers of building triangular corner ports like Mesa