stevie

The EU distance selling regulations give you a "cooling off" period of 14 days as a legal right. There seem to be quite a few music retailers giving you longer than that, should you need it. Thomann give you 30 days and gear4music between 30 and 90 days. I don't think anyone charges £30 or £40 return shipping.

Luke, we have been using the speaker on its side because the handle is on the long side. I agree with Chien that there will in theory be a minor change to the sound depending on whether the cab is vertical or horizontal, but it's unlikely to be noticeable. It would be different if we were dealing with a cab with more than one driver or one with a tweeter.

[quote name='Passinwind' timestamp='1436895227' post='2821846'] When I started building cabs with dedicated mid drivers Audax came up a lot and I would still like to try them. I settled on readily available B&C 6MD38s as used in some EAW PA cabs, and still have a pair of those in my PA tops. [/quote] I'm pretty sure EAW used the Audax as their small midrange driver and switched to the B&C when Audax went out of business. So they are bound to be quite similar. It looks like the Faital m5n12-80 will be my next purchase. Anybody got one going cheap?

The interesting thing about this Beyma driver is that it offers the best of both worlds. It goes as low as the Kappalite LF (in this cabinet) with comparable excursion capability, but its response is well behaved up into the midrange and HF. Despite the fact that it has a much longer coil than the Kappalite HO, its response actually extends higher. I've scoured the spec sheets for a comparable chassis from other manufacturers and I can't find one, even at a higher price. The downside is that its thermal power handling is lower and it's 1.5kg heavier, but that's not much of a price to pay for the huge difference in price - at least on this side of the pond.

[quote name='Chienmortbb' timestamp='1436872480' post='2821499'] On another matter. Stevie is comparing the cab to his own 15/6 cabinet. Can you tell us more about that cab? Is it your own design or based on ages boy plan. What drivers? Size and weight? [/quote] It's my own design - which means it's not necessarily helpful for comparison purposes. It's also a work in progress. The main component is a BMS 15N620 in 4 ohms (I believe Passinwind has a cab with something similar) and I currently have an Eminence 8" midrange in a separate cabinet on top crossed over passively at about 800Hz. I recently started experimenting with an Audax PR170 midrange, as that extends much higher in frequency and allows for a simpler crossover, but my aim is to eventually buy a neo midrange if I can find one as good as the Audax. At the moment it's in a cab that's comparable in size to the 12" we're putting together here - an Ashdown Mini 15, but I've carried out modifications to that with flared ports and other stuff. I also have a slightly larger cab standing by that it will probably end up in - along with my final choice of midrange driver. It's all good, clean fun, but I hate doing the woodwork...... Phil has said he might build me a cab for this design in poplar ply - which could be interesting.

Yes, I agree. With a decent eq, you can generally iron out this kind of problem (although it may turn out not to be a problem at all). I also prefer to have a well-balanced cab that allows me use my eq to fix room problems rather than cabinet problems. I tend to think of mids on bass guitar as anything between 400 and 1600Hz - and I think that the prominence I heard was probably centred at about 800Hz. Ultimately, we're just talking about sound balance. The sound was smooth, crisp and clear and there was nothing nasty or unpleasant there - just that the mids were more forward than I'm used to.

[quote name='Chienmortbb' timestamp='1436707287' post='2820060'] Stevie/Phil Did your measurements show pronounced mids or is this something that has just shown up in real life testing? [/quote] I didn't carry out a full-range measurement, I'm afraid, which would have shown up an imbalance between the bass and midrange. I did a ground plane LF measurement and a gated mid/high measurement but couldn't join them together because the first one was not calibrated. In any case, you need to factor in the changes in frequency response from the cabinet being on the floor, which makes a gated measurement problematical because it relies on filtering out all reflections. I've found that an RTA works well for checking the sound balance of a speaker in situ, but I didn't do one when I had the speakers here. I do know that my own 15" + 8" is ruler- flat on the RTA, which suits me, although others may well prefer a mid-foward balance. I can have a closer look at this when the speaker makes its way over here again.

This is where we need some feedback, Thunder. The mids definitely help the cab cut through, and it's good to know that they are there if you need them. If I were building the cab for myself, I'd probably fit a notch filter to take away some of the mids. If there is a general consensus that the box is too mid-prominent, we could do that to provide the option of a more even sound balance.

[quote name='Phil Starr' timestamp='1436697862' post='2819967'] The overall impression I'm getting with now three bassists is of a really clean open sound from these speakers. On the minus side they really show up any untidiness in your technique ..... [/quote] I'm happy that I was able to highlight that particular feature for you, Phil.

Well - I finally gigged the 1x12 last Friday. Phil drove over to one of our gigs and I swapped from my 15" + 8" to the Basschat 12 during the break. I didn't really have enought time to adjust the sound to what I wanted. The cab seemed quite forward in the midrange - so I backed off the mids using the active EQ on my bass and that seemed to do the trick. The sound seemed clearer but not as full as my own cab, but because of the circumstances, I really can't say much more about the sound quality. A tweak on the bass control of my LMIII, or more mid-cut, would probably have given me the fatness I was missing - and if I'd had more time I would have done some more tweaking. (For reference I had the LMIII tone controls flat with just a touch of HF boost). Anyway, Phil was able to have a good listen from the audience (in fact he made up most of the audience!). I can say a few things about the cab, however. It is fairly sensitive: you don't need a 1,000W amp to get it loud. The top end is detailed. Dispersion is not bad - better than your average 12, I'd venture. I had the cab on the floor and I could hear myself when I was standing a couple of feet in front of it with the band playing. I would have preferred a bit more top end in my ears, but it was acceptable. I play with a reasonably loud drummer who puts the kick through the PA. You could say we're a loud pub band. The cab had no problem keeping up - it didn't even break into a sweat. (For those who use the Markbass LM III, my master volume was on 10-11 o'clock.) I think a lot of players would never need more than just a single one of these, especially if they were able to angle it up slightly. I really like this driver a lot. We're going to try some alternatives, but the Beyma seems to offer tremendous bang for the buck and is only a couple of kgs heavier than neo alternatives at twice the price. We could do with some other players gigging these now.

Good to see at least one person on this forum has his priorities sorted!

It doesn't seem possible that anyone could manufacture an electronic device, ship it half way round the world, advertise, pack and deliver it to you for the price of a pint. I've no idea how they do it.

An ohmmeter is a valuable tool to have around the house for testing batteries, cables, etc. You can get one for under £3 delivered from eBay: http://www.ebay.co.uk/itm/Professional-Digital-LCD-AC-DC-OHM-Volt-Meter-Ammeter-Multimeter-Tester-Checker-/400923875646?pt=LH_DefaultDomain_3&hash=item5d58ecd93e Everyone should have one (and a soldering iron).

I thought we were using a 30cm speaker......

It's interesting (well at least I think it is) that our European neighbours still refer to loudspeaker sizes in inches as well as cms.

I'd estimate the weight of the 18mm birch ply option at around 18kg, or slightly less than the Bergantino HD112 (at 20kg but with a tweeter), which is manageable but not what I would call lightweight. The poplar ply version would probably be around 12-13kg.

[quote name='Thunderpaws' timestamp='1435788036' post='2812552'] An 18mm ply cab with less bracing will not behave the same way as a 12mm ply can with more bracing. But can we hear the difference? Some clever person on here might know. [/quote] This is true - and it's one of the topics we discussed in PM but were never able to resolve. We probably need to do some calculations for weight and stiffness. My personal observations are these. An unbraced 12mm cabinet of this size is unacceptable for bass, as it rings too much. Phil's bracing method was very effective in damping this ringing (unlike some commercial offerings I've tried), but his 12mm cab was not as inert as my 18mm cabinet on the knuckle-rap test. I'd say it was an acceptable compromise in view of the weight savings, but it does make the build more complicated. The big unknown is 18mm poplar ply, which would be even lighter than the 12mm birch, have better internal damping and probably require less bracing - but would cost more. It does seem to be the material of choice of the mainstream makers of high-end lightweight bass cabinets. I'd also mention that there are some pro PA cabinet manufacturers using 18mm poplar for their bass cabs (although the overwhelming majority use 18mm birch) but nobody is using 12mm birch. [quote name='Thunderpaws' timestamp='1435788036' post='2812552'] I would still go for a slightly trickier 12mm braced design. A project is a project after all. [/quote] The bracing looked tricky, but Phil is saying that in practice it isn't. So perhaps it is not really an issue.

[quote name='Phil Starr' timestamp='1435666808' post='2811125'] It was very simple, though I do have a bench saw which made it easier. [/quote] It looked very neat when I saw it. Perhaps a photo would be helpful.

[quote name='Beer of the Bass' timestamp='1435665361' post='2811099'] There's one a bit closer to me who say on their website they have a range of speciality plywoods, so I could give them a ring too. Is the Chinese poplar core ply worth a look, or should it be the European stuff? [/quote] I've no personal experience but I've heard that the Chinese stuff is to be avoided as it delaminates and is full of voids.

Poplar is a bit specialist - that's a good point. It's not something you'll find at B&Q, although I think most major cities have an outlet. There's a supplier near you in Grangemouth. My experience with wood merchants is that they will get hold of whatever you ask them for from their suppliers. It's not usually a stock item though.

Like Passinwind, I don't enjoy woodworking. I find getting a straight cut with a perfect right angle nigh on impossible. If I were to build one of these I'd want to take a cutting list to the woodmerchant and get him to cut the pieces to size which I could then take home and assemble using simple tools. I'd therefore prefer an easy build with a shelf port and perhaps one semi-circular brace or a back brace. I'd go for 18mm birch ply for ultimate quality - or 18mm poplar ply if light weight is important. 18mm chipboard would be another option for someone who wants to try out the design without investing too much initially.

[quote name='Ghost_Bass' timestamp='1435583892' post='2810239'] Will it be an option for adding a tweeter to the design and a suggested x-over (or at least a suggested x-over point)? Looking forward to this. I think i'll have a go at building one for the rehearsall space. [/quote] It shouldn't be too difficult to do, although I'm not convinced it would add much. The cheap option would be to cross over where the bass driver is 6dB down, which is about 4.5kHz. You could use something like a P. Audio PHT-407 (under a tenner, and a really nice HF unit) or the neo version, which I think is about £20. A more worthwhile alternative would be to cross over at 1.8 - 2kHz, which those drivers can cope with, but then you need a proper two-way custom-designed crossover, which would cost more.

The final measurement taken was the upper frequency response of the cab: Perhaps unsurprisingly, this matches Beyma’s latest published curve quite closely. Midrange sensitivity is around 96dB. The main cone resonance occurs at 2kHz, which is par for the course for a good quality driver. Most bass/midrange speakers break up like this at the top end. There are a few that don’t, but they are very much the exception. The resonance is mild and fairly well damped but the waterfall plot (which I did not bother saving) shows that the cone is definitely breaking up here. The highest you would want to use this driver in a PA cab is 1.5kHz but cone breakup at this frequency is not such a serious problem with bass as it is with voice, for obvious reasons. Anyway, flat to 3.5-4kHz and 12dB down at 5kHz is a result – and Beyma had fixed the 500Hz dip in the previous version, which was another piece of good news. We spent the final part of the afternoon (hurriedly) trying the cabs out with a Mark Bass LMIII. I have a 1980s Yamaha BB with a Duncan SPB-1 pickup and TI flats. My initial impression with the amp set at flat was that I would prefer a bit more bottom end and a bit more top because that’s what I have with my own system. A tiny bit of adjustment of the tone controls was enough. I would be happy to gig it like that. The real eye-opener came when we plugged in Phil’s Precision with roundwounds. With the amp flat, it was perfectly balanced. Every note sounded even playing up and down the fretboard from top to bottom. The bottom end was perfect, although this time I thought there was too much top end, as string noise was a bit excessive. It was the kind of clean, uncoloured type of sound from which you could easily dial in whatever tone you wanted because it was all there. I thought the cab sounded much better with Phil’s bass than with mine, although I’m really not sure why. The difference between the two cab tunings was not as great as I had expected from the measurements. Also, when we connected a couple of midrange drivers with crossovers at 800/900Hz (designed for another bass cab, so therefore not optimum), I thought there was a marked improvement in clarity, despite the fact that the Beyma is no slouch in the midrange (but I’ve always been a fan of a separate midrange driver anyway). Phil heard a difference, but from what he has posted, I don’t think he considered is as much of an improvement as I did. We really could have done with a commercial 1 x 12” cabinet as a reference - and someone who is used to evaluating bass guitar cabinets to assist. Both Phil and I are used to testing fullrange speakers, but evaluating a bass guitar cab subjectively is a completely different kettle of fish.