Phil Starr

[size=4][attachment=172884:clip_image002.jpg][/size] [size=4]OK update on the design process, which is back to where this thread was originally meant to be, I feel sorry for anyone who comes to this in the future to try to find information [/size] [size=4]The biggest problem we are having is to select the port dimensions. Tuning the cab is easy as winISD will calculate all this for you once you have decided what outcome you want. the problem is deciding the outcome. It is always a compromise and all the cabs you might buy have had the compromises decided for you, however high end they are.[/size] If the plot above comes out then it should show the cone excursion at 300W. The pink curve shows the cab tuned to 50Hz resonance and the yellow to 40Hz. the red horizontal line shows Xmax, the point at which the speaker coil leaves the magnet and the speaker starts to distort. You'll see that they both start to distort at 100Hz and the 40Hz tuning distorts more. Because Beyma use the worse case calculation for Xmax it is unlikely you would notice any distortion at all with the pink 50Hz tuning and in practice, probably none at the 40Hz tuning. So far, so good. The problems come below the port tuning. Look at the 30Hz line and you'll see the excursion shoots up to 11mm and 18mm. Critically at 13.5mm for this speaker the coil hits the back of the magnet, and this will destroy the speaker. Low B is 31Hz. This means the speaker won't handle 300W of low B fundamental if we tune it to 50Hz. So we tune it to 40Hz right? Well no, not necessarily, because this causes other problems. One you might be able to see on the image. The port length is bigger that the cabinet for a 40Hz tuning. More about this in my next post.

The prototype is 53x42x36cm (exterior dimensions) I don't think that will vary by more than a cm in any dimension in the final version. My rack mounted Hartke sits nicely on the largest face. Because it is a self build you can vary the shape to get the exact dimensions you want so long as the internal volume stays the same. I'm going to offer everything down to a cutting list to people who just want to make a perfect copy but the reason we are giving all the design details away is so you can tweak the design if you want.

There are two variables here, the cab and the venue. The acoustics in some venues are appalling. Low frequencies are hard enough to hear clearly at the best of times but if you are shoved into a highly reverberant space with a not very lively speaker which is pointed at your legs not your ears then you won't hear anything, even though it may be fine for the audience.

Sorry, can't do the 12th, family commitments.

There are two technical issues with using PA cabs, actually the same issues are shared with all bass cabs. Neither of them should be an issue with a properly designed PA cab. Bass needs lots of air to be shifted if it is to be loud, this means lots of cone area and/or the cone(s) need to move a long way. Cheap speakers with cheap magnets can't do this generally. PA cabs should be able to put out exactly the right amount of bass to match the output of the rest of the band so should be able to cope with bass at that sound level with no problems, otherwise what's the point? However cheap PA's compromise this and are often only used as vocal PA avoiding this issue. The other technical is distortion, if you play with lots of distortion/overdrive then it generates lots of extra high frequency energy and you will burn out the horn drivers. Not a problem if you play clean. If you bought a new PA speaker and it had DSP built in then none of this is a worry the DSP makes your speaker idiot proof and turns it down if you do something stupid. The other non- technical issue is that of taste, bass cabs are rarely uncoloured because the colour is the 'sound' of the cab. PA cans should be uncoloured so will sound different. If you like DI'd sound then you'll like using PA cabs. Another issue is cab resonance, bass cabs generally are fairly massively built to resist low frequency resonances. PA cabs are generally made to be light enough to be thrown on top of poles and are engineered to suppress resonances across the frequency spectrum. I'd avoid one of the polypropylene PA cabs as a bass monitor but most reasonable quality PA cabs will handle bass as well as most bass cabs. In some ways the bass unit in a PA cab can be more specialised for bass than a bass speaker, as the horn does all the top end. Try your cabs at home, turn the power up gradually to slightly louder than you would normally play and run up and down the lowest octave on your bass listening for any strange noises from your cabs, stop if it happens. If it doesn't you are good to go. Don't do this at a gig because the signs your speakers are being damaged will be masked by the rest of the band.

I'm struggling to do the same thing, not helped by a poor pitch control so i need to concentrate on the singing and controlling my breathing. Three tips: Practice the singing along with a recording without the bass, you have muscle memory there too as I found out when I practised in a different key to the band. If it's in memory you can spare a bit of attention to the bass too. Really mark the bit of the bass line the first word of the lyric sits over and make sure your bass and the vocal are locked in at that point, practice both with a drum machine if you can. Simplify the bass line and follow the vocal line with the rhythm, may not be ideal but far better than the bass losing timing altogether. I'll be watching for tips here myself.

Might be better to look into re-coning it, which means it is still the original speaker.

Yep the magnet material makes no significant difference as far as performance is concerned. All other things being equal the more powerful the magnet the smaller the cab needs to be and the louder the speaker will be. Powerful magnets cost, neo doubly so. Powerful ceramic magnets are very heavy though so its a trade off between the weight saving of the cab versus a heavier magnet or high cost neo. The trouble is there is another fashion for flatter more extended bass response running alongside the move to lightweight. To get this you trade efficiency so you need bigger more powerful amps for the same sound level. So, modern means neo and modern means more[size=3] amp [/size][size=4]power, but for two different reasons.[/size]

The aging of speakers is relatively complex and a range of components will change over time. Any polymers used in the construction will continue to cross bond, that is there will be new chemical bonds formed between the long chain molecules that make up the plastic and rubber parts of the speaker, mainly at the cone surround. This is why plastics become brittle with age. The old foam surrounds used to be particularly prone to this and broke down after only a few years. The edges of the cones or even the whole cone may be treated with a damping material and of course the glues which hold the speaker together are also polymers subject to this process. The wood pulp used in the cone will also age, cross-bonding between the fibres made essentially of lignin will increase but this will be overtaken by the physical breaking up of the fibres which will soften the cone over time. Actually speaker cones are not rigid pistons but are designed to flex at higher frequencies and in most bass speakers the surrounds are in any case formed from the same material as the cone itself. Most old speakers initially break down at the first roll in the surround. The fibres are mildly hygroscopic and absorb water from the atmosphere eventually swelling slightly. Then in high temperatures and dry conditions they will lose that water so go through a process of swelling and shrinking which further softens the material, the degree depends upon where you are in the world. The cone will also accumulate dust and will get heavier, lowering the resonance. You'd also expect some colonisation by fungi especially in damp conditions. Speaker coils also go through dramatic heat changes, reaching several hundred degrees during high power use this can end up distorting the coils and leading to failure of the speaker but will also heat the magnet. Depending upon the magnet material this can end up losing some power over time. Modern magnet materials and coil formers are designed to mitigate this and are pretty impressive though some 50's and 60's speakers may have lost a lot of power and drifted off spec. You wouldn't expect any mechanical component moving thousands of times a second to last forever without wear. There will be changes in sound but they aren't usually dramatic and there are many bass players out there using vintage gear quite happily.

Not sure about family commitments that weekend but if I'm free I could bring the Basschat 12" cabs along http://basschat.co.uk/topic/227904-1x12-cab-design-diary/ and do a talk about designing bass cabs.

[quote name='GrahamT' timestamp='1411291091' post='2558101'] As my job is near Taunton and I live in Hemyock, any of the above areas would work for me. I am always keen to try out new gear. Jimrs2k has built some Fearful cabs which are awesomely powerful. He lives at Ashcott, on the Bridgwater to Street road so he may be a useful local contact for you. [/quote] It would be ideal to compare the new cabs with other offerings, commercial or home builds and to try out a range of amps and basses with them. Could be fun.

[quote name='yorks5stringer' timestamp='1411148461' post='2557020'] If you'd venture into Dorset/Somerset there's always the Queens Head at Milborne Port, venue from the last Dorset Bash....? Sorry, don't want to hijack the SW Bash but it seems to have gone quiet...? [/quote] Yep that's a distinct possibility and there are a group of you who would be happy to meet there I guess.

Wait a bit and keep calm. I started playing when I was 55 and you have to ask the question how many people would have you? Secondly it always sounds awful because when you first play in a band you think it is going to sound like all the recordings you ever listened to the reality is without a proper mix and with all the problems of hearing each other it usually sounds much worse for the band than it would for the audience out front. Now playing with my fifth band I've adjusted to rehearsals and working with new bands. It takes time to sound good but after a few practices it should start to come together, if you are all experienced that happens quickly but if you have two people who are veryrusty/inexperienced you need to let it ride for a while and keep your expectations low at first. In a couple of months you'll know if you are all improving and then you can make a decision if it is for you or not, unless you have another band waiting for you already you have nothing to lose and loads to learn so stick with it for a while and see if it goes anywhere. As to not being able to learn your part because they move the goalposts, welcome to the world of musicians. At this level you are unlikely to have anyone with a sound grasp of musical theory or any language to describe what they hear in their heads. So many people talk about putting their own stamp on music but take that with a pinch of salt. As a bassist you can always get away with playing the root note in time with the drummer especially if you hit the first beat of every chord change. Once you have a half dozen practices you'll find very little changes and you can add to a basic bass line from then on. Don't expect too much at first other than to get better at each rehearsal, don't criticise band members who are probably low in self confidence anyway and enjoy yourself, it will get better.

[quote name='skidder652003' timestamp='1411145074' post='2556954'] Hey Phil if its 4 ohm, I'll try and destroy it through the SVT ! [/quote] Given your history Steve!!! You'd be welcome to try them out, with or without a meeting.

Hi Guys, I need some help. I've been designing a bass cab for Basschat and have a couple of prototypes. I think they are great but then I would wouldn't I? I need some fellow bassists to come along and give them a try and make some comments so I can tweak the design. I'm happy to just organise a venue and meet up and do this informally, or if enough people want to give a little talk on speaker design or to incorporate this into a proper bass bash. All I need is some bassists to try the cabs, I'll organise the rest. Is anyone interested? I'd look for somewhere Taunton/Axminster/Honiton area probably, though I'm open to other suggestions if someone else can find a pub that will have us.

+/- 4mm, that must explain the fit on American cars! (joke Bill ). Seriously most timber merchants in the UK are going to cut within +/- 0.5mm and my experience is better than that. Explain what you are doing and they'll take a little extra care usually. If they mess up then take it back and ask them to do it again. If they can't cut the panels for a simple rectangular box more accurately than you can with a circular saw and a sled then there is a real problem. This is a red herring frankly. Although I have all the gear in my workshop I often get the stuff cut at B&Q or wherever simply because it makes it easier to transport than 8x4 sheets. One tip is to prepare a cutting list and to mark up the cuts themselves on a drawing. I draw out an 8x4 on graph paper and mark out the panels to scale. Otherwise the usually untrained assistant starts cutting before they start thinking and you end up with a lot of waste material. Don't forget to allow for 5mm for the saw cuts if you do this.

You have 14 days I think to return to Andertons, they are good to deal with as I found out this week but you don't have much time. I've re-read your posts and I think mic technique is probably a big issue. you don't say which Sennheiser she used but using a stage mic is difficult for most people, they are mainly designed for very loud environments and to reject feedback, To do this you have to eat the mic. The SM58 is a cardioid which demands less mic technique than a supercardiod. you'd expect Sennheisers to be louder than the SM58's which indicates mic technique is an issue. A headset mic might be a good idea as once it is on you can forget about mic technique. Thinking about your needs I reckon you should think in terms of losing the guitar amp and having a single amp that does both guitar and vocals. there are three ways to go. An acoustic amp with a mic input, I've not used the Marshall but the better amps of this type have a very flat response and are no more prone to feedback than any other system, if cost isn't an issue the AER's are very good http://www.thomann.de/gb/aer_compact_60.htm?sid=f82773e9361901d92390e81571fa31e0 , there are much cheaper versions but I haven' tried them. A PA package like the Yamaha Stagepas 300, is a terrific setup for what you need, I have one of these and they are great, Two very light speakers with a 4 channel mixer and featherweight 175W amp built in. No trouble carrying in the whole PA in one journey.They were the first in the new wave of PA systems designed for exactly the sort of need you have and they were soon copied by a whole load of me-too designs which may well be as good, but I haven't tried them. http://www.soundonsound.com/sos/mar06/articles/live_stagepas.htm PA speaker route, if you just want vocals I'd strongly recommend the Wharfedales, Since my post I've used them at two gigs as vocal monitors given them a thorough going over at home and used them for PA at a couple of rehearsals, the sound is fantastic so long as there is no bass content. However if you wanted to cut down the gear you carry and rationalise your system then they only have one input so you'd need a mixer to use the guitar as well. There are plenty of PA speakers that have two inputs so they would probably be a better bet http://www.thomann.de/gb/jbl_eon_515_xt.htm However I think mic technique is the real problem and a worn mic might be the solution. The other is to practice at home, it takes a while to get used to hearing your voice amplified and if you are naturally shy it takes a while to get used to it. Did you have a budget in mind?

On a technical level there is no reason a 10 can't move as much air as a 12 as this depends upon how long the cone movement is as well as the area, they count equally. A 2x8 has a cone area roughly between that of a 10 and a 12. I'm not sure it helps but you can't decide this on cone area. The power probably matters only if you start thinking of extension cabs. 100W is probably enough to drive most of these speakers into distortion at the lowest frequencies so you'll probably have to judiciously cut a little bass if you turn the amps right up. I'd say if you intend gigging these little things then a DI out is important as you can then easily use a bit of PA support. a worthwhile extra. Fundamentally though you should base your decision on the one you like the sound of best.

I'd be a bit surprised if many bass players didn't enjoy gigging, its not the most satisfying instrument to play alone. I'm an entertainer and it's such a buzz to have people singing and dancing in time with my fingers. Nothing better than coming off with people grinning from ear to ear. The compromise is playing the songs they like rather than what I'd choose but I can listen to that any time. If I'd started younger and played originals I'd still want people to listen to it. Nothing wrong with just enjoying playing by yourself or with an intimate group of friends, or of suffering from stage fright but for me it is performing that satisfies.

the Titans are very loud, they claim 128dB which is incredibly loud., enough for vocals for a full rock band They actually have an almost hi-fi sound but the compromise for these hi tec speakers is the cabinet which is blown plastic. Really light but at high volumes and high bass levels it resonates and distorts, however as you are not using it for extreme volumes or bass I think it would suit

Sorry about your Father in Law. That's tough for your family. Playing Devil's Advocate here but why do you need to leave now, if this band are friends, they are happy to play with or without you and you haven't had to learn anything new for a while then there isn't a big commitment other than getting together to play the odd gig. It's kind of like you are the dep isn't it? When there is a gig you go and play with a few mates. If they want 'commitment' and to 'make it' then they need to have a much more professional attitude and to get themselves much more organised, and that means never going out with someone missing and playing less than the bands best and accepting gigs the band as a whole can't make. Would you be happy if they found another bassist or even if you shared it with a regular dep? How would you feel if they found another bass player? I think your other bands sound a bit flaky too if what you really enjoy is just regular gigging. Though playing with a number of bands is a lot of fun. Sounds like you need to think about what you really want first of all. I played in two bands with friends until recently and the problem is that we all had different reasons for playing and because we were friends didn't really resolve issues, it was more about friendship than music. About 8 months ago I joined a new band (all strangers) because we all wanted the same thing, It's been a revelation, practices are more purposeful, there's plenty of debate about what we want to do but little argument and we constantly push forwards. It's actually friendlier than the friends band. We get really good audience reactions and the gigs are rolling in. I'd say look at what you actually want to do with your music and re jig your commitments, start looking for a band that can share what you want out of music. If you are fond of the old band then gently let them know what you want, perhaps once you have found something. Play any gigs you have accepted of course and it is then up to you if you offer to play any gigs that come up with the old band, since it is not a big commitment. In my case I am still playing with one of my friends bands and so far there has been no conflict of interest. I suppose I am saying you don't have to make a dramatic 'I'm quitting' statement. Think about what you want and talk it through if you decide you need a change. Hope it works out. Good luck.

The yamaha stagepas are good, we've used one for years but for what you are describing are probably more than you need, a single powered speaker with a mic input will do. I've just bought a Wharfedale Titan 312 from Andertons £139, amazing quality vocal sound and really lightweight http://www.andertons.co.uk/active-pa-speakers/pid25497/cid627/wharfedale-titan-312a-grey-finish-active-pa-speaker-150w-50w.asp Won't do for bass or drums but you aren't going to do that. Only one mic input but again that's OK for what you are suggesting.

Grade BB/BB ply may have fairly extensive filling/patching on the surface veneers and some of the stuff around at the moment is tending to splinter a bit when machined. This is pretty much what I used recently when I sourced it from a builders merchant, it wasn't very flat either. On the plus side it is a good price. I was prototyping so was less bothered. The stuff they are selling at Wickes and B&Q is better quality but denser. Builders merchants tend to spec on the structural qualities of ply for it's use in building. http://www.lathamtimber.co.uk/icmeditor/HTMLEditor/images/Literature/Latham%20Brochures/Birch%20Plywood.pdf

Bills figure of 90dB seems reasonable as you'd want to match the loudest guitar sound with your bass not the quietest. In fact you'd want the bass to be able to go louder because we hear lower frequencies less well than the mids that guitars put out. I'd be looking at producing 100dB peaks so you could work at 80dB with a 20dB peak in reserve, or a dynamic range of 40dB if you prefer that way of looking at it. An average bass speaker will give about 96dB for 1W@1m, little 10's in low powered combos probably 92dB/W, an 8 in a practice amp 90dB, taking the lower figure you'd need 10W for 100dB. If you did take your Ampeg fridge 1W would be more than enough. If you are playing outdoors then you'd need four times the power as the bass would be radiated 360 degrees. This is all to be taken with a pinch of salt because we've no idea of spaces you'll be performing in or the type of music

First have a go at this, it's been here before but everyone in a band should do it from time to time. http://www.actiononhearingloss.org.uk/your-hearing/look-after-your-hearing/check-your-hearing/take-the-check.aspx Forget about eq unless your rig is just for you and not for the audience, having it sound good for you whilst the audience hears a tinny, over loud sound is for guitarists you have to eq for the audience and the room, but if you put bass through the PA you can boost tops and mids a little on-stage and boost the bass with the PA. Assuming your hearing checks out OK I really think the problem is an over loud on-stage sound. There ar tiny muscles in your middle ear that contract and lock up the tiny bones that transmit sound when it gets too loud. This limits the damage to your inner ear but distorts the sound. You stand no real chance of hearing anything clearly when it gets too loud. If you are like me and probably 90% of musicians then all the band are working harder once the adrenaline of the gig kicks in and your volume increases to beyond the sound check and rehearsal levels. Sometimes wearing ear plugs actually helps you hear better so long as they are the ones which are designed for musicians not for power tool users. Point your speakers at your ears, use a kickback or a stand, but mainly turn down. the other problem with little pubs is that in tiny spaces with low walls and the sides of the room right up close you get a lot of reverberent sound which boosts the bass, edge off the bass a bit and you should hear the rest a little better. Good luck, hope your hearing checks out.