Chienmortbb

[quote name='Passinwind' timestamp='1488940368' post='3253126'] Oops, meant the 3012LF. The one I'm thinking of has a single 3" mid driver for the 12" loaded one. We can get finally get dozens of Beyma drivers quite easily over here these days, but not the one you guys are using. It probably wouldn't be too hard to special order through the primary US dealer though, but I doubt it'd be any cheaper than the 3012LF. [/quote]I think this is the real point. The 3012LF would have been the speaker of choice it were 40/50% cheaper over here it would be a good basis for a 1x 12 plus midrange design. It would not work as well as the Beyma in a single 12 configuration like the BC Mk1.

[quote name='Passinwind' timestamp='1488917770' post='3252962'] There are some pretty nice sounding commercial cabs using the 3015LF that weigh around 25 pounds and are not too large, but yeah, not all that inexpensive at $650 in the US before shipping. [/quote]We normally assume an exchange rate of £1=$1 especially when it applies to US made products imported to the UK so £650 actually equates to just short of $800. Do those cabs with 15s have mid range and HF drivers too Charlie?

As Im said earlier it wa my plan to build two cabinets but Stevie convinced me that one would be enough. The Beyma SM 212 has a massive excursions of 8.3mm as I remember, only beaten by the Eminence Kappalite 3012LF. However on the Kappalite, the "LF" is the clue, it really is just a woofer and would probably need a more sophisticated crossover and/or a mid range driver and maybe a tweeter as used by Greenboy in his FEARfull and FEARless models. See [url="https://scontent-lht6-1.xx.fbcdn.net/v/t1.0-0/q89/p480x480/10906135_1021323607896101_2539545370011067118_n.jpg?oh=8b07b3a72c11ec2bf6773bf25a063e1a&oe=59707441"]HERE[/url] [size=4]Then the cabinet would be bigger, heavier and a lot more expensive. [/size] =

[quote name='Gottastopbuyinggear' timestamp='1488737304' post='3251419'] If we were talking about both drivers being 8 ohm then would the crossover need to be any different from the one you've already designed? I could understand it being different for a 4 ohm woofer. [/quote]A quality crossover will include components that take into account the performance and specifications of the woofer as well as the mid range/high frequency units. This is the part that most manufacturers skip. You can see from Stevie's drawing in post 47(reposted below) the specific components that are used for the Beyma SM212 with the P-Audio Tweeter. A different woofer will require different components. The crossover using the Celestion Compression Horn is more complicated.

I have just arrived home after visiting Stevie and hearing the cabinet with the with the Celestion compression driver. This time I also took my TC Electronic BC212 for comparison. The BC212 uses two Eminence 12 drivers together with a good Eminence compression driver. The Basschat 1X12 MK2+ uses a good Celestion Compression Driver and P-Audio Horn in place of the P-Audio Tweeter that Stevie has already described. I won't bore you with tecnicalities but suffice too say that the BC MK2 with custom crossover and the Celestion HF unit/P-Audio Horn walked all over the TC BC212 in every way. It was louder, it had more lows, it had real mids, it was smooth. Whether you were playing bass guitar or bass and piano the sound was chalk and cheese. In comparison the BC was harsh. Stevie and I both have test disks that have some basic bass guitar record without any processing and that is what we used to listen to the cabinets. That way we take the variables out of the equation. No variations in technique, no differences in equipment. Initially we tried the TC Electronic BC212 before I heard the new design. We both agreed it sounded OK. Then we played the same content through the MK2 BC 1x12. I had heard the Mk 2 before with the P-Audio tweeter and it was great but this time we had a reference. It may not have been a boutique bass cab but at a retail price of £400 new, the BC212 was a fair comparison. I should say that the original MK1 design was a good one. If you are looking for 1x12 without a tweeter, you probably won't find a good one that costs less that 3 times the price. When Phil chose the BM212 from Beyma he found a winner. Is it perfect? No it is heavy compared to some of the neodymium 12s out there but its all round performance is hard to match. Excursion close to the Eminence 3012LF but half the price and with more useable mids/highs. The original design goal Phil set was to produce a cabinet that could produce 120dB SPL and have a reasonable top end ,so as to compete with Animal (Animal is the codename for a heavy drummer). The MK1 did just that. Without losing any of that, the Mk2 design, whether using the P-Audio Tweeter or the Celestion Compression Driver, retains all that and adds the dispersion at mid-high frequencies that a 12" driver cannot do alone. It should also be said that a good crossover was the secret ingredient (I would say great but Stevie would blush). Add that and you have a small cabinet that is hard to beat even with a commercial 2x12. The secret is the dispersion. I am 6ft+ and even standing next to the cabinet, almost on top of it, I can hear myself. Many stacks are purchased purely so that the musician can here themselves on stage. Others are purchased because the single cab cannot "shift enough air. I suspect we will not have either problem with this cabinet. When I first met Stevie he demonstrated a (modified) Roland cab with a 1x12 tweeter that was properly crossed over and had added bracing/damping. We compared it to the MK1 and while we both agreed the MK1 had a better low frequency response, the extra that came from the Roland shocked me. It was what persuaded me to have a two way design. Today we compared that same Roland Cab with the BC 1x12 and it sounded flat by comparison. I have to thank Stevie, despite the fact that he has cost me money on what was supposed to be a budget cabinet build. I don't think I could buy a single cab solution, as well engineered, as this for the money I can afford to pay. That is a slight fib as I was going to build two, until I was convinced that one would do the job. I will effuse no more but I am going to build my cab in time for the South West Bass Bash on April 2nd, so anyone going is invited to try it and comment. I will also be playing through it at the Beer Festival in Bournemouth on the 16th April.

[quote name='fftc' timestamp='1488568184' post='3250187'] Thanks guys. Mk1 sounds closer to my skill level. I've said this before, but it's worth repeating. I think it's fantastic that you are all sharing your knowledge and experience on here, and as someone who is now a bit less clueless than I was before I read these threads I appreciate that. Thanks for clarifying on the driver Steve. I mistakenly picked up somewhere that Mk2 had different driver. [/quote]One of the reasons Phil chose the SM212 for the MK1, was its extend mid/upper range. Compared to most other drivers it is very good. However dispersion is similar to every 12" driver. The advantage of the Beyma SM212 over most 12" drivers is that the extended upper range gives more flexibility. It can be used as a single driver "system" (MK1) or as th[size=4]e woofer in a two or three way system that is both more "[/size][size=4]Hi-Fi" and has wider dispersion [/size][size=4]than[/size][size=4] most commercial and [/size][size=4]even[/size][size=4] boutique cabs. [/size] [size=4]​I may be entering uncharted or even [/size]blameworthy[size=4] territory here but there are few 12" drivers [/size]better[size=4] suited to Bass Guitar than [/size]the[size=4] SM212 in a well designed cabinet. It would take too long to explain why, [/size]but[size=4] for example [/size]it has a better high end than the Kappalite 3012LF and a better low end and displacement than the Kappalite 3012HO. So why is it not used more often by manufacturers? Most boutique makers are in the USA, and Beyma are not well represented there. If you manufacture in the far east, Eminence have an OEM factory that provides drivers for silly money. We all have to eat and the low hanging fruit is very attractive.

If you put an output transformer on an SS amp it would behave in the same way as the thermionic valve /vacuum tube amp. However why put a huge lump of metal in there is you don't need it?

[quote name='Phil Starr' timestamp='1488564251' post='3250127'] That's right, the MK1 was designed so that anyone could build it with no special skills or tools. and if you prefer a tweeterless cab it's a pretty decent one. one of the reasons we've designed these cabs so publicly is that you can adapt them if you want, and I hope share any experiences you gain. I recommended 18mm ply in the MK1 to avoid any complex bracing. It'll match most commercial cabs. Stevie and John wanted to push the envelope further and I cant wait to hear the results. There's no reason why you shouldn't build a mk1 and add in more bracing at a later date or a mk2 without a horn and crossover. Between us we can guide you through the process if you want. Our intention is to demystify speaker building and what is going on inside your commercial unit if you don't. [/quote]You and Stevie always seem to put it better than me, but that is exactly as I see it. Either cab is OK as they both have the same volume, just different dimensions. The Mk2 is easier to mod as we had different design goals. I would happily gig with the MK1.

[quote name='fftc' timestamp='1488547049' post='3249892'] A Mk1 vs Mk2 comparison would be very helpful thanks. There are a few reasons why I'd be favouring the Mk1 build to the Mk2. Cost and complexity of the tweeter and crossover, the port design being a bit more involved, and the slightly more 'hi-fi' nature of the Mk2. A concern would be that the Mk2 without the crossover and tweeter would not perform as well as the Mk1 due to the different drivers. I just wondered if the Mk2 bracing would be an upgrade to the Mk1 cab? From what I've read of those who have built a Mk1 it sounds ideal for me. The Mk2 might be extra everything when I don't need it IYSWIM. [/quote]The MK2 was never meant to replace the MK1. It was meant to be another offering indeed my build with the Compression Horn will be a Mk2+ but will be a lot more expensive than the MK2 as presented here. The real advantage of the MK2 is the single large port but that also makes it more difficult to make. The MK1 was designed so that anyone could build it. However with Stevie's kind offer of the loan of a hole cutter it will be much easier to make the MK2.

I would recommend building the MK2 but it is more complex You could put the new port into the MK1 but the baffle is smaller and so there will be np room for upgrading later. I suggest you what until Ghost-bass and Stevie have finalised the drawings and then decide. As far as I know they ar a few days away. I will do a MK1 v Mk2 comparison later if it helps.

One of these days I will write a thread on watts and amplifier classes and valves V SS. I need to get fit including taking lots of Vitamin D ( and in the interest of fairness Vitamins A, B and A/. On a serious note I need to be in the right frame of mind as I know it will generate lots of ill-informed flack.

Bill is right of course but I suspect there are many worse that that Ashdown plot out there. The other useful figure would be the off axis response,

Re-reading Phil's comments, I have to agree that there is a potential problem with plain butt joints on plywood. The adhesive works best on the face of the board and less well on the cut edges. Hence battening each edge solves that problem. The (partial) solution to this is to seal the cut edge with a 50/50 solution of water and PVA woodworking adhesive prior to making the butt joint. Of course we have not published the design as yet but the bracing is comprehensive and that can only add to the strength. The offline "discussion" as to how to construct the cabinet was "frank" and of course, Phil is right that the strength of a fully edge attend cab will be stronger that one without the edge bracing.

i don't want to steal Stevie's thunder but I will try you explain the thought processes after three beers. Firstly, 15mm Poplar ply. The stock we can get is 9 ply and that is for either 15 or 18mm. To try to keep the weight down we have gone for 15mm. So 6mm dowels can be used with care. I have not tried pocket holes on 15mm stock so I cannot comment although I have a pocket hole jig and use it or other projects. In theory there is no problem in porting at the back but again I will bow to Stevie's superior knowledge. I know Stevie was planning on looking at alternative drivers/voicings to satisfy the Old School brigade but I don't think the Kappalites were what he was planning to use. The Kappalite 3012LF is a great LF driver but there is some debate as to whether it is ideal in a bass cabinet. I am going out on a limb here but the SM212 performs better overall than any of the Eminence drivers I have heard over the LF and mid range. Its problem, like all 12" speakers, is beaming. It is the beaming that we are trying to design out. To explain beaming, think of lighting. The two extremes are spot lights and flood lights. A spot sends out a narrow beam of light picking out a single performer. Great for Sinatra or Robbie Williams but... where's the band? Beaming is a spotlight and we want a floodlight. The problem, with beaming for the working bassist is that unless you have ears in your knees, you need either a separate monitor, a second cab atop the first, IEMs, or a cab designed for wide dispersion to hear yourself on stage. Having heard one of the Eminence drivers in the prototype MK2 and MK1 cab, the only thing the Kappalites will give you, i[b][i]n my opinion[/i][/b], is light weight and an empty wallet. The 3012LF has a peak in the response at about 2Khz. For the P-Audio tweeter the crossover frequency needs to be higher than that. The peak on the 3012HO is much higher but is not the LF beast that the 3012LF is. It has an Xmax of only(sic) 6.2mm compared to 8.25mm for the Beyma SM212 and 9.1mm for the Kappalite 3012LF. So the HO cannot move as much air. Of course the Kappalites are 2Kgs or 5lbs lighter and that may be a reason for using them. [size=4]Both Eminence drivers have higher power ratings but the difference is small enough to ignore. The SM212 is rated at 350W, the 3012HO at 400 [/size]and the[size=4] LF at 450. The difference between 350W to 450W is under 1dB[/size] in an ideal world and 1dB is audio's JND (just noticeable difference) in ideal (quiet) conditions. Standing next to Animal you won't hear it. Of course the Kappalites have bigger voice coils (3" rather than the 2.5" for the SM212) so may handle more power that the raw specs would suggest. If you want a flat response, HiFi voicing, then the SM212 is ideal. If you want Old School then other drivers need to be considered, Stevie has both the MK1 and MK2 prototype cabinets and they will stay with him so he can check different drivers. One last thing, don't rear port until ,Stevie has confirmed or trashed my views.

When I contacted Stevie about this originally I was aiming for a single driver with a weight coming in at about 14KG. However once I heard one of Stevie's cabs I was hooked on a two way. From my rough, calcs, the tweetered version should come in something under 16Kg and the compression horn version that I am building 17Kg. A good HF unit is weighty and although the P-Audio Tweeter and the Celestiion compression driver are about the same weight, the crossover for the compression horn weighs and costs more as it crosses over much lower than the Tweeter. As I understand it Stevie will publish the twittered design initially. [size=4]Stevie will be able to give you more info though. [/size] As for the size, the final size is to be confirmed (non) but the prototype was taller than the MK1 (60mm wish )and the other two dimensions were smaller. About 10mm smaller on the width, and 40mm ish on the depth. Sorry to be vague but I built the prototype from 18mm ply and the final design will call for 15mm. Regarding the build, I will let Phil answer the dowel question but I will be using them.

Agreed if there is nothing wrong its fine. Just enjoy it.

What Norris said plus if you have put a new bridge on the action(string height) will need to be adjusted. There are two real p[possibilities, High fret or if not a high fret, you may have the dreaded ski jump where there is a bend upwards at the body end of the neck.

Its a 250Watt amp. I think that is what the OP was getting at. There was no such thing as Dynamic Output watts.

Of course the maximum voltage swing is a limiting factor in the power output by an amplifier but is not the only one. Many amplifiers have power supplies that cannot supply the extra current needed by 4R speakers. As an example, the Hartke 3500 Is rated at 250 watts into 8R and 350 watts in to 4R. The power supply cannot supply enough current. Power is the product of Volts x Amps so Voltage is important but cannot be considered in isolation. As for the actual SPL, if using the same driver in the same enclosure, not driven too hard there will be a correlation between a change in the power output by the amp and and change in the acoustic output from the speaker system. It may not be linear but over a limited range it will be affixed relationship. Of course if you drive the speaker too hard, power compression becomes a factor and the relationship is broken.

Assuming both cabs are 8 ohms, that will be fine. If the Head had two output sockets it is better practice to take a cable from the head directly to each cabinet. Otherwise all the power goes into the top cable,

Wow this is unmissable. Will a day be enough time?

As Stevie says I am going to build the cab with a Celestion Compression Driver coupled with a P-Audio horn. The horn has unusually wide dispersion and should be useful for allowing me to hear myself even when just in front of the cabinet. We really need some commmercial cabs for comparison purposes. I have a TC BC212, it is a mid range cab but it would be really helpful to have more cabs that we can test in controlled conditions. Can you help? The knowledge we are gaining and putting on here is useful even if you don't want to build a cabinet. Some of the findings have surprised me and with open minds, free of commercial pressures, we have no axes to grind. The port situation is a good example. One big horn (ooh err Mrs) is a lot better than a few small ones. It is likely that multiple slot ports are also an issue for exactly the same reason, who knows what else we will find with enough cabs to check. Anyway thanks for reading and if you could help in any way....let Stevie know.

Do you have a picture of the plastic part. I have used the ,K&M version before but now have financial constraints. Ido have a good workshop though and could probably kno I ups metal part to replace the plastic part.

Do you have a picture of the plastic part. I have used the ,K&M version before but now have financial constraints. Ido have a good workshop though and could probably kno I ups metal part to replace the plastic one. Douroucoulis have a picture ofit?

[quote name='BassBunny' timestamp='1487842250' post='3243365'] As it's a Class D amp, the options are limited as to self repair. I would get in touch with Marshall, (who now own Eden), and arrange to send it to them. all my dealings with them have been excellent. If it is still under warranty, then they will sort for free. Oh and what Jack said although Eden still have that killer tone for me. [/quote]Yes my dealings with Marshall have been second to none.