Phil Starr

[quote name='hogman' timestamp='1409162923' post='2537020'] I am currently having a veritable nightmare with my nemesis 2x10 and 1x15 cabs, there humble speakers dying, granted they have had a hard life. Got manufacturers replacement speakers that were both replaced by myself I am more than qualified to do this, I ran them in at low volume for 72 hours as I do with all my drivers. They have had very little hard use (compared to what they used to get I was gigging between 3 and 5 nights a week and out 4 - 5 a month now) and suffered no real abuse, I use an Ampeg SVT 3 and have since I bought the cabs. The speakers looked the same but are obviously not. Could you suggest a better quality speaker for the cabs (Eden Nemesis). To say I am disappointed is an understatement. The cabs have served me well for over about years ( being fed a diet from punk rock to Jazz and experimental playing) and I have replaced the 10's but not the 15 and was hoping to get a lot more out of them than 7 Months. Not to bothered about price n drivers is what I am after the cabs are a great size. The horns are a bit shouty. Any help would be ace! [/quote] You need to give us some help here, We need to know the internal volume of the cab or the internal measurements, if you know the thickness of the walls you can work it out from the external measurements or you can remove the speaker to get inside. We also need to know the size no and length of any ports.

Andertons have an offer on at the moment, the Mi12 is £199 [url="http://www.andertons.co.uk/bass-cabs/pid24233/cid686/ashdown-mibass-mi12-1x12-cab.asp"]http://www.andertons...12-1x12-cab.asp[/url] This might be the thread they are referring to [url="http://basschat.co.uk/topic/227904-1x12-cab-design-diary/"]http://basschat.co.u...b-design-diary/[/url] as usual it has drifted a little but there are enough details on there for you to go ahead and build one already and the final design will be ready soon, I promise [url="http://basschat.co.uk/topic/227904-1x12-cab-design-diary/"]http://basschat.co.u...b-design-diary/[/url] . If you ask on the thread I can put the dimensions back up. Someone ( 6V6) has already built a close 'version' of this [url="http://basschat.co.uk/topic/200152-1x12-diy-cab-build/page__hl__1x12"]http://basschat.co.u.../page__hl__1x12[/url] which will give you an independant view of how it might sound.

Well I never, I was going to challenge you on that one Stevie but I checked, Youngs modulus for steel is 210,000 v's 70,000 N mm-2 for aluminium depending upon which alloy you are talking about. So you are right. However of course rigidity and stiffness are not the same and cast aluminium structures are thicker for the same weight so aluminium chassis may be more rigid even if steel is stiffer. It is certainly true that all the bigger ceramic magnet speakers have had cast chassis for the extra rigidity for years. Bill is right though, I think, about heat dispersion for neo speakers, their light weight would not need particularly good load bearing but it is difficult to radiate heat from small structures with a relatively low surface area. [url="http://aluminium.matter.org.uk/content/html/eng/default.asp?catid=217&pageid=2144417130"]http://aluminium.mat...geid=2144417130[/url] [url="http://en.wikipedia.org/wiki/Young%27s_modulus"]http://en.wikipedia.org/wiki/Young's_modulus[/url]

Don't paint your cones, depending upon their make they will be made of carefully mixed plant fibres (markbass use a bit of banana fibre in the mix I think) possibly treated with a coating to damp resonances and adjusted for weight and stiffness. Adding paint will affect both the mass and stiffness and ultimately the sound of the speaker. I think the OP has decided changing the grille is better anyway but just in case anyone else is considering it.

Sorry but that isn't [size=4]right[/size] at all, you'll have noticed that I said all other things being equal, as you say the laws of physics aren't swayed by opinion. The resonant frequency is inversely proportional to the square root of Mms [size=2][/size] which I'm sure you know. For the non technical the resonant frequency is determined by the mass and the compliance of the speaker. Compliance is the floppiness of the cone support, The bendiness of the corrugated spider and the cone surround combined. For the examples Bill gave the compliance and the mass are both different. That's exactly why I wanted to make the point about it being a little more complex than 'the only difference is dispersion'. You can tune a small speaker lower by making a heavier (and usually stiffer as a result) cone or by raising the floppiness, these in turn affect other speaker parameters. I could give plenty of examples of speakers where the large cones are heavier but I don't think people will have too many difficulties in seeing that an 18" cone will usually be heavier than a 6" cone for example.

Sorry to spoil the party but dispersion isn't the only factor affected by cone diameter. First of all you can't vary cone size without changing either its mass or cone thickness both of which will alter the sound it produces. A heavier cone will resonate at a lower frequency and ultimately reproduce lower frequencies as a result, all other things being equal. It will also take more energy to accelerate and decelerate, changing its ability to track high frequencies and its transient behaviour. It's also true that speakers with high surface areas tend to be more efficient, all other things being equal. Even the dispersion issue isn't quite as clearcut as presented. This assumes the cone moves as a piston, and it won't. In practice they all flex to a greater or lesser degree so that more high frequency sound is radiated from the centre of the cone and for most speakers the effective radiating area reduces with frequency. As a result it is possible for a single 15" speaker both to produce appreciable output at the upper frequencies of a bass and to have acceptable radiation of those frequencies. As in the Barefaced compact. You'll have noticed the repeat of 'all other things being equal' and of course they won't be. There are lots of variables other than cone diameter and all have an effect on the sound the final design will make. What Bill is saying is that there isn't a characteristic 'sound' made by a 15 or a 10 which is completely right, but it is easier to make a 15 go louder and deeper than a 10 and much harder to get a decent top end out of a large speaker. The 'sound' depends upon a lot of factors not just cone size.

The aluminium basket does two things potentially. It is more rigid than its steel counterpart and this might help in the longevity of the speaker. Ceramic magnets can be pretty heavy and the basket can potentially distort over time. The second advantage is that aluminium is a great conductor of heat and the frame may help in cooling the magnet and coil. This could mean less power compression as the speaker heats up. Notice the conditionals, maybes and mights. I've not seen any figures on this though Bill may have some sources to offer. Generally I prefer to go for the cast frame although I've had few problems recently with pressed steel frames. Cast frames are always more expensive to implement and there are potential benefits so they are one indicator of a little more care in the speakers design/implementation. I'm using the Fane 10-300's with the steel frame in my stage monitors however with no problems at all so far.

All of the above is good advice. There are three abilities that will get you constant work and none of them are to do with musical ability. The most important is the ability to network, go to the places musicians hang out and talk to people, listen to them carefully and store up their knowledge and share your own. If they know there's a bassist going spare and one of their mates needs a bassist... Equally if you can help them a bit with a contact they'll remember you and pass you on more often. The second ability is the one in shortest supply with musicians, organisation. I'm a crap bassist but a born organiser, Book rehearsal spaces, gigs, run the PA and lights, blow noses carry spare fuses and wipe their little bums at times. I play with people much better than me and so far no problems finding a band. The third ability is self awareness, what are you actually like to work with and what are you looking for in a band? Know your own strengths and weaknesses especially personality traits and work with them. Also recognise what you are prepared to compromise over and what is a sticking point for you. the more you are prepared to compromise the more desirable you will be as a bandmate. Originals bands are always going to be tricky as it demands big egos. If one of you wants to write power ballads and the others metal it really isn't going to work. If you are open minded and respectful of other peoples tastes it can work better. OK musical ability does matter, but there are so many talented and skilled people out there that it takes other skills to get out of the bedroom.

[quote name='davehux' timestamp='1408018061' post='2526276'] I use a Behringer F1220A http://www.amazon.co.uk/gp/product/B0028GWJCG/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 Solid, well made, with rubber bumpers on all the corners . Loads of power (forget the 125W thing, it is seriously loud) Nice 3 way EQ. The Feedback filter actually works!!! I know Behringer doesn't get much love on here, but mine gigs regularly and I've had no trouble at all from it. Hard to beat in a 'bangs for your buck' contest [/quote] It seems to me they are getting better. The limits to the 1220's are their volume. Max 113 dB from memory. However for most bands who play on cramped stages this should be enough. Once your monitors start to give feedback problems any extra volume isn't usable anyway. I've not tried them but I wouldn't dismiss them without hearing them.

[quote name='LukeFRC' timestamp='1408054028' post='2526775'] odd off topic question..... say I went and bought a RCF HD12a.... what would stop that (and a preamp) working as a powered bass cab? [/quote] Only the expense. There are several threads on using pa speakers as bass speakers and if you like the sound of DId bass then these speakers should hadle this as well as any. It is still a 1x12 though, so enough for some people but not everyone. Try before you buy though.

[quote name='LukeFRC' timestamp='1408054028' post='2526775'] odd off topic question..... say I went and bought a RCF HD12a.... what would stop that (and a preamp) working as a powered bass cab? [/quote] Only the expense. There are several threads on using pa speakers as bass speakers and if you like the sound of DId bass then these speakers should hadle this as well as any. It is still a 1x12 though, so enough for some people but not everyone. Try before you buy though.

For testing I use a PA amp to get a flat response. Usually a Peavey IPR1600. I've been gigging the cabs with my Hartke 3500. My drummer complained that he couldn't hear his snare when I turned it up so I don't think sound levels are a problem.

Bill is of course absolutely right about this. The interesting thing is about what the implications are for us as bassists. If you want a single speaker to do the job for you then you have to have something engineered for high volume displacement. This usually has a cost in terms of efficiency or a large exotic and expensive magnet system. The other thing is that doubling the number of drivers gives you 3dB of extra sensitivity. 6dB if your amp can maintain the voltage swing. Go to an 8x10 and you have a potential 12dB of sensitivity or 9dB at the same wattage. Although this comes at the cost of the speakers radiation interfering with each other to make a lumpy bumpy frequency response and radiation pattern. This extra efficiency means that your system is using much less power. 3db is half the power and 10db a tenth. So instead of 400W into an exotic lightweight you might be using 40W into an 8x10 for the same sound level, and only 5W into each of the eight speakers. If you are using the same amp it is going to run cooler and maintain its output, it is also much less likely to distort because of peaks in your playing. More importantly probably the speakers will run cool, 400W into a tiny coil trapped in a tiny air space inside a magnet does get very hot. Speakers running consistently high powers run very hot and the resistance of the coil rises reducing the speakers output so the sound changes as they warm up. Of course this is only one variable, there are many other differences to take into consideration but there are distinct advantages in multiple speakers vertically stacked.

I've tried the Eminence delta because I had one laying around, I wouldn't recommend it. We are going to try the Eminence beta 12A-2 which is a much better driver than the old 12A and I hope to get hold of a 3012HO to try. I've cut a load of spare baffles and the speakers are just clamped in so we can swap them really easily so if anyone wants to volunteer a speaker to try..... having said that the Beyma models well and sounds just how it models so is likely to be what we recommend. Stevie has three modelling programs, WinISD, one which uses the same engine that Eminence use and another that I'm not familiar with. I'll let him reply. Interestingly they don't agree with each other all the time.

All good questions. The port issue is really the outstanding detail we need to sort before publishing the design. Exactly the discussions you are having here are going on between us with one extra problem. I'll re read the discussions we have been having and may come back on this but in essence the debate is 'how big a port is big enough?'. More than one formula and more than one target maximum port velocity have been suggested to avoid power compression and port noises. Stevie in particular is keen on flared ports and they do have advantages but I am reluctant to add to the cost and problems of sourcing all the bits and pieces. The other issues are practical ones. If you make the ports too big they are also too long to fit the cab. Since ease of build is high on the design spec I really don't want to have to fold the port and prefer to use a shelf port. The prototype has round ports because this enables me to vary port area and tuning easily. As you suggest the front and rear panels are removable for prototyping purposes. Since this is a home build project and an open source design it is a simple matter for people to adapt the construction to their own taste and pockets. We will give enough information for people to go for the ports they prefer and the construction techniques they prefer. My experience is that using screws and glue is more likely to have a positive result where people are working without extensive woodworking tools so i am going to recommend they use screws. I use Titebond aliphatic woodworking adhesives because that's what my local woodworking shop Axminster Power Tools sells, but I also use ordinary white woodworking PVA. I've never had a joint leak or break.

The art710 is cheaper than the Yamaha from Thomann. I'd choose that.

They were the DXR10 and the ART410 recently discontinued but available here at a discount. BOth makes have excellent reputations for reliability. The drivers in the RCF's have a great reputation. I use passive club series Yamahas and have a soft spot for them but there was a real lack of detail from the DXRs, I was underwhelmed, they weren't awful, just a bit boxy and compressed with a lack of detail in the vocals. Particularly noticeable on a duet with two female voices I use for testing, the ARTs separated the voices, the DXRs turned them into a mush. By the way my Yamaha floor monitors are 15s (bought second hand) another reason to go for 10's is they are too big for most of the venues we play and I have just moved to 10's for that reason. I've also bought some Behringer B205Ds which work surprisingly well for vocal monitors if you want to go really small

The Ley Arms in Kenn are very supportive of music. Might be worth asking. I'd happily bring the prototype basschat 1x12's along for people to try..

I am another one to prefer 10's for monitors. The essential thing for the monitor is to give good mid frequencies especially for guitar and vocals, it is a rare 12 or15 which will do this. I recently tried running the Yamaha against the RCF, thanks to PMT in Bristol, the RCF are much better.

[quote name='redstriper' timestamp='1406217414' post='2509442'] The Flite cabs are made of a composite material, I'm not sure of the details but I think it's foam sandwiched between thin ply. They are very light, under 10kg loaded with the 3015LF and having got used to such lightweight, I am loathe to change them. [b]They also sound better than any other 15" cab that I've tried, which is quite a few, but I've been advised that they are too small to get the best from the 3015LF.[/b] [/quote] This is kind of what we are saying, all designs are compromises, you like the sound of your cabs because the compromises work for you. Just relax about the cab and enjoy playing bass. Don't worry about the little bit of extra bass that theory tells you you might have had. Our cab has exactly the same compromise.

[quote name='Chienmortbb' timestamp='1406117220' post='2508451'] To the three musketeers, My comments were not meant as a criticism just advice. I hope I did not upset anyone. I have found it a good idea to keep an open mind when it comes to design and i am learning a lot from what you guys are doing. Much of what I have learnt is from guys like Bill, Alex and Duke, and much of that seemed counterintuitive at the time. Bill on particular continues to push the boundaries on enclosure design. Keep up the good work. [/quote] No, we won't take offense and it is good to question everything. It's the only way to learn and we certainly don't get everything right, even though we try quite hard to distinguish between opinion and physics.

[quote name='redstriper' timestamp='1406038450' post='2507746'] My requirement is for a lightweight cab suitable for dub reggae, so I do not need much treble or upper midrange. I currently use a small cab loaded with an Eminence 3015LF, which sounds good but it doesn't go as low as the new ACME 15" cab. It would sound better in a larger box, but I don't want to do that. Stevie suggested replacing the driver with a [color=#282828][font=helvetica, arial, sans-serif]3012LF, which would be better suited to the smaller box dimensions and sound deeper than the 3015LF.[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]Would anyone else here care to comment on this idea, before I take the plunge?[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]Specifically, what differences in tone and volume should I expect and is it a worthwhile modification, considering the work and cost?[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]Apologies for the derailment.[/font][/color] [/quote] if you are serious about building a cab then there are plenty of people here who will have a go at helping you, why not start another thread and see what we come up with

[quote name='LawrenceH' timestamp='1406036918' post='2507721'] I still think the limits imposed by the shape of the LF transfer function on the bass end are being ignored, or at least not given much priority. The only practical way of making eg a Vanderkley sound like an Acme in the bass would be with DSP filtering, regardless of xmax/power limitations, because the EQ on even quite a flexible amp won't be able to sufficiently compensate for the difference in cabs to give a similar overall roll-off curve. This is another reason to think carefully about tuning in the 40Hz versus the 50Hz regions, since tuning lower can give a curve that is easier to EQ within the range you actually care about using the EQ controls found on a typical amp (eg 12dB/oct shelving filters for the bass). [/quote] [quote name='Chienmortbb' timestamp='1406103815' post='2508272'] The tuning frequency of a cabinet should be chosen to suit the driver. Most mid-bass drivers do not behave well when tuned too low. It can compromise the max power before XMAx is exceeded and so increase fartout. It also increases the very low frequency travel of the cone, increasing the boominess. Most shelving type bass comtrols make this worse. If you need the extreme low end response ( and there are very good reason why you don't) you probanly should look at say the Eminenve Kappalite 3012LF, Precision Devices PD12SB40 or some of the Beyma & Faital Pro dedicated bass frequency drivers. [/quote] Just in case people haven't been following this for all six pages Lawrence is one of the people working on this design. there is some flexibility in where to tune the cabinet and as you say it affects excursion and power handling in the bottom octave as well as frequency response. Fortunately it does this in ways which we fully understand (we as in anyone who can do the maths or run the software, I'm not claiming anything more than a rudimentary understanding of T/S) so we've modeled the SM212 in this cab at these frequencies. In fact the reason I'm keen on 40Hz is that it limits excursion more at 30Hz than the 50Hz tuning. I reckon someone is going to be foolish enough to connect up a 5string with no filter and pump 350W through it and i want to keep the speaker intact if possible. Stevie prefers to keep the tuning at 50Hz which keeps excursion down further up the frequency band and a slightly better response overall. So don't just mess with tuning and think that it's OK, you need to run the models, and realise that designers are making compromises all the time to get a preferred balance of features. We're actually going to resolve this by building both and listening to the differences and by running some high power tests with test signals.

Again I'd kind of come at it from a different angle partly because you are really asking about the design of the drivers. For a given magnet size you can make the speaker go deeper by giving it a heavier cone. You can make it louder by making it lighter or by giving it a short voice coil which sits neatly inside the magnet gap. If you want a high sound level and lots of bass you need a long coil so that some part of the coil stays inside the magnet all the time. This is inefficient because at any one time only part of the coil is doing any useful work. 40 years ago amps were expensive and mainly low powered, you got round this by using very efficient speakers and sacrificing Xmax and deep bass. If you wanted to increase the volume you used more speakers, hence the 8x10, or a big complex cab. Cheap amps make it sensible to use less efficient speakers with long excursions making up for fewer speakers, however there is a limit. The speaker coil is still fairly fragile with thin copper wire and it doesn't cool well trapped inside the magnet so there is always an upper limit to the power a speaker can handle 450W for the 3" coil of the kappalite and 300W ish for a 2"coil. So yes, you can trade efficiency for 'better bass' with more power being the cost but only within limits.

[quote name='funkle' timestamp='1405963650' post='2507016'] Hah, yes, sorry about the lengthy post I made. I hope it was relevant though - mainly in regards the choices you have to make as a designer (How low? How efficient? How big a box?) and the trade-offs which are inherent to those choices. Bill, Alex, Dave Green, Andy Lewis, Roger Baer, Duke LeJeune, etc already have worked out their own compromises with the newer drivers - it seems like to buy a cab you haven't been able to hear first you have to work out what the compromises are and what the designer intended. I have a question. Does high Xmax (with high power handling, thermal and mechanical) + sufficient power compensate for low efficiency of a woofer? I'm thinking of e.g. the 3012LF vs the 3012HO here... [/quote] That's not how I would go about choosing between these two. they are designed for entirely different uses. The HO has pretty impressive Xmax anyway and a frequwncy response at the top end that makes it usable on its own as a bass driver. The LF really has to be used with another driver and the associated crossover, and I'd crossover below 1kHz probably because it has a nasty resonance peak at about 1.8k. Then i'd be modelling the LF response in my target size of cab, as we've just been discussing anything below 50Hz could just be an embarrassment of riches in a real room, but it would depend upon how it was going to be used. WinISD or any of the other modelling software is going to tell you about what excursion you will get at what power and what the maximum output is so all these would come into it before I made a final choice. For instance we decided that we wanted something that gave us 120dB over most of the pass band and would handle 300W down to 50Hz staying within Xlim down to 40Hz. If the speaker does all those they were good enough irrespective of price and efficiency and we could look at other things like their price and top end response. The Beyma we chose wasn't in the end significantly different from the 3012HO to make it worth spending the extra, both fitted our criteria. If we were in the States where the Beyma is an expensive import and the Eminence cheaper we might have said the lightweight of the HO was worth having.