Phil Starr

Before you start this think about what you are trying to achieve. Is this to repair a cab which seems to be damaged or a restoration of something you love? Maybe you want to upgrade it? The thing is that there is only one way of making this like new and that is replacing the original drivers. There are probably a lot of substitutes that will work perfectly well in your cab but they will all sound different from the original drivers. For some it might ba a subtle difference and for others it could be dramatically different. WinISD is about the bass response and it is quite possible to get something close to the response you currently have but the response of speakers at the top end varies a lot and the computer modelling wont help there. This cab has a tweeter and crossover and that complicates the matching process. The moment you change the speakers you don't have an Aggy you have a box with different speakers and a different sound that looks like an Aggy. It could sound better or worse of course. The first thing is to say is that speakers don't usually rattle when they are ****ed. Rattle sounds like something is loose in the cab. Maybe the speakers aren't properly tightened down any more or a joint has broken which could be re-glued. Maybe a lead has come loose and is rattling against the speaker? We can talk you through trying to fix it if you want? The original speakers might be expensive but if you only have to replace a couple might be cheaper than four new ones. Four Eminence Deltas would set you back £360 for example. You can get European made speakers cheaper but not by much if you want good quality. Generally speaking it's as cheap or cheaper to trade in a cab and buy a used cab than to do a speaker swap, changing speakers is likely to reduce the value of your cab over keeping it original so long as it is in good working order. If you just fancy a project then that is great, we can talk about what you are trying to achieve and try and find something to suit. I'd try and fix the cab first though.

Shut up and.... no I can't be so rude There are a few Beymas that are really good value, the CMV range are across the board good value. It's a shame they stopped making the SM212 though. In this case the choice of the Celestion Pulse was a good one mainly because of it's mid-range performance. Most bass/mid speakers have a pronounced peak at cone break up. At high frequencies the out part of the cone can't keep up with the centre and the cone starts to flex and this creates frequency anomalies. For a 10 the response is fairly flat and rolls off evenly and this makes adding a horn driven through a simple high pass filter relatively simple. To get a flat response from most bass/mids you need to have a 'proper' crossover and control the roll off for the bass unit. The inductors for this tend to be large and relatively expensive and beyond that you often get other frequency problems which need extra components and design work to tame. You'd be amazed at the manufacturers who don't bother doing more than a cursory job on their crossovers. It's probably why some bassists don't like horns; there's nothing wrong with the horn but the crossover leaves little frequency peaks that sound harsh/distorted/honky. So Win ISD models the bass response and you may well find better 10's but the Pulse was chosen because it gave good enough bass but a really helpful treble that enabled a good response with just three cheap components in the crossover.

Hi Al, As ever mine was just a factual post. There was a study and both in terms of economics and Live music performances Australia has done way better than us. That is still true. The rate of vaccination in Australia is poor for a wealthy country and frankly the worlds media coverage of Astra Zeneca hasn't helped, taking aspirin or paracetomol is far more dangerous and my guess is most anti-vaxers pop pills with a lot less caution than I do. Getting one bit of the equation right doesn't stop you making other mistakes. I note that the governments science advisors including SAGE members have a model that is predicting another 50,000 people killed by Covid in the next 12 months as a median figure due to the current relaxations. They clearly see this as acceptable. That's of course not including other cancelled treatments due to Covid bed blocking. The NHS is already starting to turn people away from some hospitals. I note also that the trials of opening night clubs and other indoor events have resulted in over a third of the participants contracting covid and that was the Alpha strain. Indoor events are pretty much super-spreader events. Outdoor ones much safer Further I am concerned that letting Delta rip through a population where around 1/3 of the population is unproteced is, according to DR Phillip Hammond "the prefect petri dish for breeding vaccine resistance." Of course vaccine resistance means the virus is also bypassing natural immunity. Vaccines only work by triggering our natural immune system. There are a number of coronavirus genes out there we wouldn't want to meet with Delta. Viruses swap genetic material if you have co-infection. Co infection becomes common with something as infectious as Delta. One of the genes we know is out there, as reported in New Scientist, would make Covid 100 times more infectious than Alpha. Others out there would make it more deadly than Delta. There is no predicting random comings together but when the improbable looks so bad it is better to avoid the random. I'm sure the migration of lemmings is also a glorious sight, I know how it ends!

I think that's all fair comment, though I only built the cab @stevie did the tuning and he did this on the basis of measurement of the final cabs response. The original design was shaped by the need to keep everything easy to build and the availability in the UK of a ready made port was an important factor. We were looking for something cheap, easy to obtain and sourced from a well established supplier so likely to be available for a few years. This one also has a decent lip to cover up any dodgy cutting of the hole. When I did the modelling on WinISD I found my 'best' response was higher than the final tuning and that the original port without the addition of extra length would give that tuning. The extra card extension was added as a result of frequency tests on a built prototype. The frequency plots are there in the text somewhere. In my original version of the cab I used plastic guttering down pipe. One of the things we discovered testing is that two narrow ports start to make port noises (chuffing) at lower power levels than a single bigger port with the same cross sectional area. We hadn't seen this in any literature. Like @agedhorse I shudder at the idea of folded ports. Like all the commercial designs we have looked at and pretty much any practical cab there are compromises in this design. Like the crossover design and choice of drivers the port was an issue of cost and availability. Actually 52Hz sounds about right, I measured 53Hz by looking at impedance on mine. I don't think it is worth re-tuning unless Steve comes along and says there is a problem, my cab sounds great given the cost of the components and pretty much as i'd have expected from the design software.

Get a couple of coats of Tuff Coat on it and it will look the business. You've done a good job with that and I really hope you get a lot of happy hours using it. I think you are right about the volume, WinISD shows a broad band output of about 118dB at 200W which is fairly typical for a 10" speaker. Adding a second would give you 123-4dB depending upon the amp which puts you well into the gigging range. It would work well with an untweetered Pulse10 in the same sized cab underneath if you wanted to save a little money. In terms of practicality I use mine as my go to for rehearsals. I like it for gigs too because I have PA support so it is just a monitor and is plenty loud enough for me to hear everything and it sounds good. The sound engineer loves it because it's not overwhelming the vocal mics and my drummer is not so keen because he likes to 'feel' the bass. I don't think building it in 12mm ply would give you any advantages other than weight saving and maybe a better quality ply would be tougher and easier to finish. Have you weighed the cab? Mine came out at dead on 10kg. Thanks for the review, it really helps anyone thinking of a build having an opinion from someone unconnected with the design. Well done Phil

Yeah 15mm helps a lot as does denser/heavier ply. My preference is for 18mm hardwood ply. Wickes in particular used to do a really nice marine ply with good facing veneers. It's a long time since I've been to Wickes due to the plague but they still sold a nice exterior ply last time I went. For my own use I do like a really tough cab which is not going to disintegrate if it gets a bit damp. It's a tough life going between van and gig. Fortunately cabs are getting smaller and ultimate light weight is not a big concern for me, and let's face it these cabs are pretty small. This cab is 12mm poplar ply because that is what Stevie preferred. My original 'Easy Build' cab was 12mm because that was what i had enough off cuts of to build the cab. Not very scientific! What I'd really like to do is build a series of cabs all the same internal volume and weight with different bracing systems and compare them for cab induced resonances. Is a 9mm cab with an extensive equal mass of bracing better than an 18mm cab with no bracing, or enough better to be worth the effort for the home builder. There is a lot of theory about panel resonances and the car industry has done a lot of work to silence panel resonances. What there isn't is a simple piece of software to design the bracing for a speaker cab so a lot of it is a combination of experience and suck it and see. A friend of mine works for Jaguar/Land Rover and one day I'm going to pump her for inside information. Most of what the auto industry do is to add mass in critical places and they use a lot of 'lossy' materials to damp resonances. My current hi-fi speakers have a lead/MDF sandwich structure with a plastic foam joining them. I'll leave the lead lined bass cab to Trace Elliott though

Blue Aran - The UK's no.1 Loudspeaker Component Stockist > Speaker Components > Crossovers & Components > Fuse Bulbs the problem is which one, like all 'fuses' they come at different values. They are just light bulbs but you need one that heats up (and increases its resistance as a result) at just the right point to protect the tweeter but not cut it out unnecessarily. The bit you are looking at is just the glass case it's the coil inside that is doing the business. However this one seems to work so it isn't needed (probably) If you just want to test it then take it out and just put a wire across the terminals keep the power reasonable and you shouldn't damage the tweeter but it it's the bulb that's causing the fault it would go away.

Just in case anyone is following this sorry tale this is the ending. I don't know if the call to Romford resulted in any action as predictably there was no follow up email and no action at all with the delivery. I then had a week of trying to ring Romford including 5 requests for a call back a couple of emails and a lot of posts on their social media. I made over 20 calls of varying length none of which were answered at all this time. At one point after telling me how important my call was and that they would get to my call they hung up. I wonder what you do when a business won't respond to any attempt to communicate. I also emailed the German store and after a week.... no reply. I finally resorted to ringing back each time I was cut off. After slightly more than 10 attempts someone picked up. It sounded like a very weary teenager but he was polite and so was I. It turns out according to him that all the calls are answered in the shop by whoever isn't serving. That would explain no calls back and no answering. I guess they serve people in the shop first so only answer when they are absolutely empty. Anyway in the 20 mins or so i'd spent on the phone there had been movement DV247 Music Store had actually given the courier my order. Unfortunately the courier is based in the middle of the floods in Germany, can't blame them for that and at least I then knew my order hadn't been lost. It took another few days to reach customs where my previous delivery had stumbled but this time they had the paperwork right. Three days to reach Exeter who delivered a clearly opened, and very battered parcel the next afternoon. That morning I got a generic but apologetic email from Germany, so they did reply in the end. Everything inside was fine however, the two lights work perfectly and the new ABS bass hardcase is great, for £55 it's pretty fabulous. I like a happy ending So would I do it again? Well first of all I don't think they are dishonest as some are saying on the internet, just completely disorganised and beyond that the Romford store is just not set up to deal with online trading. I think the first parcel wouldn't have arrived without chasing but the second one would have. For me the average time to arrive was 4 weeks and I spent probably the best part of a day chasing. Their own brand stuff is genuinely good value and i did probably save £100 in the end. If anything breaks I know I'm in for a world of trouble. Warranties mean nothing if people won't communicate. I wish I'd paid the extra to be honest. I'd warn people to be extremely cautious about ordering anything from DV247 for the foreseeable future as you will be buying with no acceptable after sales backup and potential long delays. Be aware that you aren't ordering from a UK company and they are probably further from sorting UK exports than their other German rivals.

Bad luck, you wouldn't want to have to sort this at a gig. I think I might check some of my gear. Hope you sort it all.

I'd personally be surprised if they did use the same drivers as the 7 series. They make and sell a wide range of bare drivers and speaker driver manufacture is where they come from. They seem to have a very active design team and a policy of constant steady product development so this doesn't come as a surprise. They don't make a dud as far as I can see and I'm quite prepared to believe these are better than the 7 series. A more rigid cab would be an improvement and that may be contributing to extra weight. They may also have increased the bass driver's excursion, their bare drivers are often not spectacular in that area. I had my 310's on poles to test and program my new mixer (also RCF) and they sound stunning on poles in a room with decent acoustics, to date I've only used them as floor monitors so getting them away from floor reinforcement really opened them up. vocals were stunning and that is just about their cheapest speaker. I'm looking at 732's as optimum for me at the moment. There's a point where cost increases give only marginal improvement and any band I play in wouldn't merit better rendition of a rubbish signal I'd take the 2000W+ with a big pinch of salt, it will be music power or peak power or some such nonsense. The heat dissipation and excursion of the drivers mean that they wouldn't handle this power and the DSP will stop it reaching the speaker anyway. Class D watts are so cheap and light a lot of manufacturers are using a standard amp to power all their speakers and throttling them down with the DSP to match the drivers. The advertising departments love it because they can claim 2100W. Everyone is at it at the moment and there is a bit of an advertising arms race. It looks like they are aiming these at the lower end of the hire and touring market. I've little doubt they sound better than the 7 series, they have a knack of introducing well worked out products and optimised designs. I can't wait to hear my first one and see what they've done this time.

The baffle brace you've already done helps a lot but adding the back to front brace sorted the problem completely for me. I need to amend the build and drawings to include it but I tried a few options on the prototype so a photo of what's left would probably be quite confusing. Running test tones didn't show a lot of problems with vibration of the rear panel but you need something to fix the front to back strut to and a simple H shaped brace is easy to do and every little helps. Looking forward to hearing how it sounds, it's a lovely moment when you plug it all in and hear your first bass sounds

looking good, have you braced by the horn/port/speaker on the baffle? It's a real weak spot and we had real problems taming a resonance there. The fix was a brace across between the bass driver and the port/horn and a similar one across the rear panel with a third brace connecting them front to back. I just used the same material I had for the rest of the cab so you should be able to use any offcuts for that.

There's not much in a crossover which will cause crackling, as Bill said the bulb usually either works or it doesn't. I'd be checking leads first and trying to see if I get the same crackle with a different bass amp and leads. Good luck, intermittent faults are always a bother to find. Ooh, I'm a supporting member, that's new.

Or you could try the Zoom B1-four. Headphone output, amp and cab emulations drum tracks and fx, Stereo input for jamming along and loads of other stuff too. I run mine off batteries but it runs off a USB supply and has a dc input also. It's my go to practice machine and with the sims and fx built in you can sound great. if only I sounded like that live

Nothing wrong with you or WinISD. This was Stevie's design, I designed the basic 30l box for a 12" project and built the box untuned for Stevie to develop. Once the design was finalised it came back to me and i rebuilt it to the original design and added an extra brace. Before I did I ran it through WinISD and got the same result you did. First I know Stevie checks the tuning after building the cab. In practice the computer models only get you so close. Some of the data we get from manufacturers is only approximate, is hard to measure completely accurately and subject to manufacturing spread. There are also other factors like leakage in the cab and around the speaker that change the tuning (there's something called Ql that allows for that) but not mentioned in some of the simpler explanations. I don't know what Stevie's target tuning was but I do know he would have measured it after building the cab and tweaking the port to suit. It's all in his diary somewhere. Xmax is measured differently by manufacturers (not necessarily a fiddle) It's meant to tell you when the coil moves out of the magnetic field which extends beyond the magnet itself. Some use a distortion measurement to give Xmax as the sound measurably distorts when the coil moves too far. Others use a mathematical formula to calculate the size of the magnetic field but Celestion use the old fashioned worst case calculation of half the difference between the coil length and the magnet gap depth. They pretty much all say how they calculate Xmax so it's not a problem for us. The point is that the coil doesn't suddenly move out of the magnetic field and xmax tries to identify when it first starts to leave the magnets control. Eminence for example would say this speaker has an Xmax of around 5.5mm so we aren't too worried. The curve you have is the same shape for all speakers in a ported cab and pretty much none of them can handle the full thermally rated power without exceeding Xmax. That's right, none of them including all those expensive boutique wonders. So why won't this speaker blow and why aren't there thousands of broken bass speakers? The answer is that there isn't much fundamental coming out of the bass pickups, most of the energy is in the second harmonic and upwards, the pickups are well away from the centre of the strings where the fundamental is loudest. The bass is effectively rolled off by the positioning of the pickups and the position of the plucking hand. We are all familiar with the bridge pups having less bass than the neck pups. So build with confidence

Well I finally got through to Romford. There's been some movement and the Germans have finally passed the order to the German delivery company. By this time they of course are on the middle of catastrophic flooding and the roads are blocked so I think it's only fair to allow them a delay It looks like it has passed through and is finally being transferred to the UK couriers. The next step will happen when someone at Parcelforce scans the barcode. I chatted briefly to the guy at the other end. He's actually serving in the shop and they only answer the 'phone when they don't have customers. It must be a thankless task too, if everyone has had the same problems I've experienced. In the end I made over 25 calls stretching over several days. Most of these calls ended up being cut off after being told to hang on "your call is important to us". Emails and other messages are not responded to and the ring back service is not working at all. Music Store the German company are having problems with their couriers and their IT and although i can accept I'm unlucky there are obviously hundreds of dissatisfied customers in the UK. That's a lot of bad luck. I've saved about £60 in buying their own brand lights. It's probably taken half a day's work to get the two failed deliveries to work and I don't think one of the deliveries would have come through at all without my intervention, at no stage have I really known what is going on and their emails and phone answers have proved to be inaccurate. If anything goes wrong with the lights then I suspect I'm in for another world of pain. If i'd known in advance I'd have gone for the best UK supplier, it's not worth that time to save £60. I'd recommend avoiding them until they sort out couriers, IT and some sort of UK call centre or at least additional facilities at the Romford Store. I'm sure Brexit and Covid haven't helped but it's not a professional service at the moment. If anything does go wrong you don't want a contract with a company who don't respond to emails, answer the phone or communicate the facts accurately. I'll let you all know if the stuff arrives

Well done, it's always rewarding to see a project carried through, I hope you have many happy hours and hopefully a few gigs with your speaker.

Yeah Markbass aren't very supportive for users in contrast with Ashdown for example. My Tube needs a repair (I dropped it so not their fault) and they aren't forthcoming with a schematic, extracting any information from them is like pulling teeth.

I have the MB Tube 500, the 'tube' inside is a miniature tube soldered directly into the circuit board, there doesn't seem to be any special heatsinking or dispersal measures employed other than the normal fan so I suspect there isn't a lot of heat produced by the tube.. I haven't had the chance to compare it directly with the LMIII though so there may be differences I'm unaware of. You'll have the chance to see if there are any practical modifications when you take the old amp out. Obviously if there are any vents in the casings they need to be unobstructed when fitted in your combo, so if you find any extra venting in the case you will need to ensure airflow through them. I suspect you won't. Why not contact Mark Bass and ask them?

Good advice, if you like the sound and just want more then using the same speaker is the way to go. Anything else and you are back to having to audition it. Of course you may not need a second speaker.

As I say there are a lot of amps around at the moment that are 500w into 4ohms 300 into 8ohms and Ashdown amps do this too. The power stage is fairly standard across a lot of amps just as a lot of car manufacturers share engines across different makes. It doesn't make sense for everyone to repeat the same design over and again and they all use the same chips anyway. This also makes a lot of sense as the speakers generally will only handle around the 300W mark. To be honest 300W into a fairly ordinary modern 15 is likely to give you a sound output of maybe 120-125db which should be easily enough to match the drums and more than enough to permanently damage your hearing. The other thing is that this is a new band and a chance to agree in advance that you won't be fighting a volume war. If you aren't filling the room with a 1x15/300W then it would be much better to turn up the PA than try to do it from behind the singer and the vocal mics.

I use old duvets as my source of polyester wadding. I'm also currently eyeing up a memory foam mattress topper, probably not what I want but I hate wasting anything. If you want the old fashioned felt most carpet warehouses (not some of the big sheds though) still provide it and will sell you a metre. They also will also have cardboard tubes the perfect size for speaker ports which are used to wrap carpet around.

I'm now having real trouble contacting the Romford people on the phone. I've rung several times waiting an average 10 minutes at a time. Don't bother with their frequently offered 'press one if you want us to call you back' they won't. Offers of "I'll chase it and email you" aren't any better, they won't do that either. I've tried their social media, it's full of similar complaints.

You say the South East, Andertons have their shop in Guildford if that is near you then you could scratch that itch by going and trying both.