stevie

That's quite big. A 2x12 cab is normally half that size. I agree that the Celestion bass drivers are good though. The new Pulse 12 would probably work, or you could get a pair of the BL12-200X, which appears to be the same driver and is available for £45 from Lean. Assuming the baffle is 18mm thick, cut two holes 127mm in the baffle for your ports.

Silverfoxnik was selling a couple of relatively lightweight JBL cabs which would work well with these. The cutouts are for a 12" driver, but your tens would work fine if you were to cut a simple circular sub-baffle for them. Then you'd have the choice of one cab or two. http://basschat.co.uk/topic/300635-fs-two-jbl-4646a-12-speaker-cabs-unloaded-l25-each-ono-pp/page__p__3373633__hl__jbl__fromsearch__1#entry3373633

Not that one. It's a guitar cab with an open back and isn't designed to reproduce bass frequencies. Looks smart and is a good price though. The maker might have something similar for bass. You could always ask. The cab and driver is still going to weigh 10kgs.

I do believe you're right. Never heard of F-Bass before, but they sure sound good. Sounds just like an ATK on that track though (trying to maintain some kind of credibility here.....).

Here's a very entertaining YouTube track that features an ATK quite strongly (no idea about the model): https://youtu.be/tJzlHBN3BT4 Extraordinary musicianship throughout that band.

Sorry for the delay in replying. It could be these ones: <http://www.ebay.co.uk/itm/39213-2x-MNC-Speaker-Port-Cabinet-Bass-Reflex-Tube-44mm/291694230421?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D2%26asc%3D48155%26meid%3Dd155c9af925643c9972daecacab05632%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D281946720890&_trksid=p2047675.c100005.m1851>

Sure! It's as Alex described: in its simplest terms, you get a bass boost that fattens the sound up. I do try to keep my posts as jargon-free as possible, but sometimes you can't avoid it.

Alex, I said nothing about whether the cancellations were problematic; I just said they were there and you seem to agree that they are inevitable. But if there are cancellations, summing cannot be consistent, which makes frequency response uniformity impossible. It should be obvious why that matters. The gain you get from doubling cone area and power is frequency dependent - that’s true. When two cones are closely coupled (up to a quarter wavelength apart) you will get an extra 6dB in output. However, the theory also states that two drivers a half wavelength apart will cancel and cause comb filtering due to the different arrival times of the sound sources. The frequency and depth of these peaks and dips will vary depending on where you (and your audience) are standing. You cannot simply ignore this: it is important. One of the Adamson user manuals provides the formula for what happens when you use two 8” drivers together: “In this example we show two mid frequency drivers. The acoustic centres are 8” apart. If we use the same formula as we did on the 18” driver, 8” = .66 feet 1130/.66 = 1696Hz 1696Hz /2 – 848Hz we can calculate the maximum usable frequency. This time it allows a maximum of 848Hz. Anything above this frequency will result in interference when listening off axis.” I went into my workshop, stacked two fullrange 12” systems and measured the results. As expected, the pair was 6dB louder than the individual systems at low frequencies. However, above 600Hz or so the responses were extremely uneven, the peaks and dips changing dramatically with every step I took. This is the response on axis and 1.5 metres away from the top cabinet (red one cab, green two cabs): This is the response 30 degrees off axis, level with the top of the top cab (red one cab, green two cabs): In both cases you can see the half wavelength cancellation at around 700Hz and the peaks and dips above. What’s interesting is that the output from the top cab on its own (red) is greater at the measuring position between 400 and 1kHz than when it is used together with the bottom cab (green) – despite the extra power going into the system. Of course, this is only two points in space, but it should be enough to show what I am talking about. So how serious is this interference between stacked drivers really? Alex says that “most of the inevitable cancellations are not problematic”. It doesn’t look like that to me, and some speaker designers think they are serious enough to take measures to mitigate them. JBL’s JRX225 2x15 + horn PA cab is one example. This is how the blurb describes it: “A ‘Quasi 3-Way’ design offers the extra bass for which a dual fifteen system is designed, but without sacrificing performance in the critical mid-range. The upper woofer produces mid-frequencies and bass, while the lower woofer concentrates on bass only. The reduction in mid-range phase cancellation greatly improves midrange sound quality and coverage.” JBL clearly thinks it’s problematic - otherwise, why bother?. Peavey thinks so too because they do the same thing. Then there is Community, dB Technologies, Cerwin Vega, Wharfedale, Bose – and that’s just from a quick google. And yes, let’s not forget Barefaced! Its 2x10 uses exactly the same technique of rolling off one driver to prevent them from interfering with each other in the midrange. I quote: “Both drivers in the Two10 work in unison to produce big bass and punchy mids but to improve dispersion only one has treble output - just like a PA line array........ By only letting higher mids and treble come from one speaker we get much better dispersion through those frequencies so you have more consistent tone around the stage and venue.” Which is more of less what JBL says. It seems that Alex agrees with me after all.

That looks like a fairly standard commercial port that has been cut to size. Take a look here: <http://www.wilmslow-audio.co.uk/reflex-ports-31-c.asp>. It's probably one of those (you don't mention the diameter).

Sorry, but you don't get more output across the whole sonic spectrum. While you do get additional output in the lows, in the mids and highs you get lots of cancellation, and the frequency response gets tilted towards the bottom end. This is why adding more cabs can be good when you have a box that is shouty and lacking in bass - a description that applies to a lot of small bass cabs. (I'm not referring to the Barefaced 10 specifically, as I've never heard one).

Just bought a bass from Mike and it was a thoroughly pleasant transation in every way. Bass was well packed and arrived quickly. Excellent!

I can definitely recommend Roland Lumby in Salford.

Gluing up the second side panel. (Evostik Resin W before you ask). And it's on! And the final piece of the jigsaw fits into place. Yes, it does look like a cab now, but there's still a fair bit to do. The only woodwork left is cutting the hole at the back for the Speakon. Before I paint it and fit it out, I'll check the resonance performance and decide whether to add any more bracing - but that can wait until the weekend. So close and yet so far! In case anyone is reading this and wondering why on earth is he messing about building his own cabinet.... Well, the cabinet makes a big difference to how a speaker sounds and performs, and you can't buy a bass cabinet as good as this. If you want do do a job properly, do it yourself.

Here is my trusty right-angle guide in action again. A few more braces on the top panel and we're ready to fix the baffle. Baffle on. It's starting to look a bit like a cabinet now. Just for interest, here is a photo of the clamping arrangement I used on the baffle. A bit belt and braces, I admit. I expect that laying the cabinet flat and putting some weights on the baffle would have done the same job.

This is the horn I'll be using for the HF. It's an asymmetrical design, which means its dispersion is 100 degrees at the top of the horn and 60 degrees at the bottom. The benefit is that you get maximum dispersion when you (and your bandmates) are close to and above the horn, but the dispersion narrows for those in the farfield, that is, the audience. The best of both worlds in other words. Also, the vertical dispersion is wide in an upward direction (towards your ears) and narrow in a downward direction (towards the floor). Having gigged with this horn arrangement, I can report that it works brilliantly. And it looks like this in the cab. Now to glue the first side panel on. In theory, gravity will do the job, but I decided to use clamps just because I have them. This is where I hit my first real snag. There was slight warpage at one end of the side panel, caused in all likelihood by the cut panels having sat in my cold garage for several months. Anyway, the back and side panel did not meet at 90 degrees at the bottom of the side panel. I've shown this on the photo below - sorry it's out of focus. The only way of fixing this was to now attach the bottom panel with screws to straighten the panel up. So, despite my original intention not to use any screws, I was forced to do so here. The next job was placing a vertical row of bracing strips up the side panel. As this may or may not be overkill, I won't install any on the opposite panel - so that I can check what effect they are having. Here we go. [PLEASE NOTE: I LATER FOUND THAT THESE SIDE PANEL BRACING STRIPS WERE INDEED OVERKILL AND NOT REALLY NECESSARY.]

For the horn cutout, I made a cardboard template based on the hole in the prototype cab. Unfortunately, my sawing was a bit off - so I used some fibreglass filler to make good. And started installing the t-nuts. I cut the hole for the port with my 5" hole saw.

I think Ghost Bass is capable of recognising loss of bass when he hears it. Maybe you should revise your theory, Bill, because I hear what he hears when I lift a cabinet up a couple of feet. You seem to be confusing half space conditions with floor bounce. It's perfectly easy to measure.

OK, Jack. Consider yourself provisionally committed!

The MNT has a much better bass driver. I'd expect it to handle most gigs on its own. The driver in the EXT isn't as capable. If it were my money (but it's not), I'd spend the extra, as I can't be bothered carrying multiple cabinets.

Great! Once we get a bit closer to 10, I'll make some serious enquiries and get a more concrete idea of price. No need to commit until then obviously.

Good move! I'm sure Phil will be along shortly.

Hi Jack, I'd be hoping for around £60 to £70, but that is obviously a guesstimate at this stage. We need to amortise the cost of programming the CAD design for the CNC machine. OEM quantities and prices normally start at around 50 units. We should be able to negotiate a decent deal with a smaller quantity, but nobody is going to get excited about supplying ones and twos. I'm sure we could also negotiate a good price for powder coated grilles and for t-nuts, feet, corners, paint, etc. (as well as drivers), especially if we're canny about delivery charges.

[quote name='discreet' timestamp='1505901353' post='3375038'] This. You don't lose coupling on most stands. I use one of [url="https://www.pmtonline.co.uk/stagg-gas-4-2-guitar-amplifier-stand?utm_source=google&utm_medium=shopping&gclid=EAIaIQobChMIsLH6rL-z1gIVzbvtCh04_gOAEAQYASABEgIFGPD_BwE"]these[/url]. Adjustable, portable and affordable. [/quote] You won't lose bottom end with one of those. I'm not sure what the definition of a tall stand is, but if you go any higher than 18", you will lose bottom end.

That's true, Jack. But power handling at LF will drop to about 80W. Although they won't go as low as a single, two of those 10s in the same cab will handle about 200W.

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