Phil Starr

All cone loudspeakers flex at high frequencies and adding a second whizzer cone to boost the highs was a common trick back in the 70's when a lot of PA speakers lacked horns and a crossover. There are still a few manufacturers making "full range" 12" drivers such as this The use of Aluminium in speaker cones has a long history, as @stevie has said and the characteristics are well known: stiffer than most fibre cones, poor damping of cone resonance and very pronounced breakup modes at high power and frequencies. Often aluminum was used with other materials to damp the resonances or to further stiffen the cone to get pistonic movement. There was even a craze for DIYers to add aluminium foil to their hi fi speakers at one point For pulp cones there is a lot of careful mixing of different plant fibres to get the right mixture of stiffness and self damping of resonance so people who design the drive units can to an extent control the way the cone behaves under breakup. I can remember one speaker that used banana fibres in the mix. I can't believe the people who came up with Hartke's signature gimmick weren't aware of this, or of it's marketing potential. Given the involvement of Larry Hartke I'd imagine a lot of this would simply be him asking for a 'bit more of a brighter tone' and then picking something that sounded good to him after a few iterations. They wouldn't have been looking for a flat response, just something that sounded good and would sell well. I quite liked my Hartke

you'd have to buy the ears I'm not sure if they would still be available, maybe look for one which is already rack mounted or has the ears

Yes it's all about tuning a whle set of frequency dependent factors, some of them characteristic of the driver and others of the box itself. Obviously you cant really change the characteristics of the driver other than by going for a different one. Basically you have control of the volume of the box and in a ported enclosure the resonance of the cab. Essentially the volume of the cab affects the bass response, a large volume giving more bass with a lower roll off point but with a drooping response, a small cab raises the roll off point and can give a significant boost in output around the cut off point which is at a higher frequency. That boost can become unpleasant and you can have a cab which is too big or too small. There's a Goldilocks size for each speaker and an area within which you can fiddle around a bit and optimise the output to your design spec or just your taste. With a ported cab you aim to extend the flat area of the output by getting the port tuned just below the point where the speaker's output us falling and the cone is starting to flap around outside it's safe excursion limits. At the tuning point the cab resonates on it's own (sort of) and 180deg out of phase with the cone which started the resonance. That means the air in the cab is moving the 'wrong' way and creates enough pressure on the speaker cone to stop it moving, What you hear is all coming out of the port. The Goldilocks point for the cab is where it is 'maximally flat' the flattest response possible. WINIsd goes for those first (They are called things like QB3, BB4, SBB4 and C4) and they can be calculated simply just knowing two parameters Qts and Vas. The clever bit of programs like WINIsd is that you can go off piste, They can calculate exactly how far the cone can move at every frequency and work out the frequency response, power handling, excursion and so on for pretty much any design changes you make. That's brilliant because it's so quick if like me you've ever had to do the calculations by hand. If you are interested I can go through the process that helped me come up with the original House Jam cab to Illustrate one approach to designing a cab and choosing the right driver to go in it.

Another factor with a capacitor is that the whole design of this cab with the very high tuning of 87Hz was to get the flattest response possible down to below 80 Hz. As you can see with your own WINIsd plot it's hard to get a flat response low down with other tunings. All cab design is a matter of compromise and this one was done by compromising on power handling and the speaker being almost unloaded below 70Hz in part mitigted by it's intended use with a Gnome/Elf/BAM style amp which has a bit of HPF going on. I'm a bit prejudiced against a simple in line capacitor. In the olden days when I built amps I found a few that really didn't lke a capacitative load. In addition the capacitor produces a phase shift. @stevie is more expert than I but I instinctively wouldn't want that happening at the port tuning frequency. Being lazy I haven't looked at any calculations though

Even the 68mm port is a bit on the small side. 75mm would be better. I use drainpipe because it's easy to get hold of and you can get hole saws to cut a 68mm hole. It's part of the easy build philosophy behind my BassChat designs and I think I mentioned this somewhere in the text. We did specify the Blue Aran ports early on but availability was so patchy people were pausing their builds so I went back to drainpipe. The micro amps are 130W into 8 ohms.

You almost certainly have a tone control which will roll off the bass by 12db or more. It would be easier to just use that as a starting point, not least because it costs you nothing and you can restore the system back to normal when that has finished. I don't want to speculate too much but anyone using the cab for the first time will sense the loss of the bottom frequencies and probably boost the bass on their amp or bass if it is active. We've all played with guitarists who swear blind that they haven't turned up even when you can see it on the meters. Bassists can be just as naughty The thing is that it is perfectly acceptable to use a big amp with a small speaker if you are aware of all the parameters. As the owner of everything you know the risks and will be careful accordingly. For a bassist just jamming with their mates and no knowledge of the gear involved you'll just go for it. Just swapping from a bridge pup to a neck pup could be enbough to put you in the red zone. At open mic nights I reckon I'd match my cabs to double the amp power for 'safety' as you have no idea what fx or playing style you will come across and some people are brutal with their equipment.

Just back from having impressions taken by Michelle at Snugs HQ. My lord it is hard to find, I thought we were rural. No phone signal either so it's hard to ring in. Michelle evenmtually hd to come out onto the road and flag me down on the way past. Anyway its a very simple procedure, a foam block is pushed into your ears and a two part resin injected which takes 3or 4 minutes to set. I sing a little so was asked to use a bite block, I think all it was doing was keeping my mouth open and still. The resin/gel sets with no heat, no real force is needed, not a suggestion of discomfort thoughout. it was all really a non event. 10 mins later I was saying goodbye. I get the moulds next year as Snugs are closed for Christmas I'm looking forward to trying these, the amount of sound that was blocked once the gloop was injected was impressive, probably years since I've been somewhere tht quiet, it promises well for the in-ears when I get the new moulds. I also discovered that I have particularly narrow ear canals but also rather high, like a letter box on it's side I guess, no wonder I couldn't get round plugs to seal. I let you all know when I get the final moulds back next year.

Sorry Al, I'm leading you astray again. On the plus side you'll be blown away by the sound per pound ratio. I still covet your new mixer though

That’s a tricky one. I think you have to decide that yourself. The speaker would handle bass and it has the full protection of the DSP which is probably common to all RCF stuff. A single speaker would be 6db down in volume though. I’d be mixing in stereo at home too so a single speaker wasn’t something I ever considered. I suppose £89 for a bass combo that sounds great is a bargain though. You could drive it off your mixer or something like a Zoom.

This was with my duo, two vocals, bass, guitar and a drumtrack going through a small desk into a pair of these. In my 'study' which is probably 3mx4m the volume was around our on-stage volume at gigs and loud enough that we had to amplify the acoustic guitar when we used it. The sound quality is stunning, certainly a match for hi-fi costing double and this is with the built in amps included.

The problem was probably excessive excursion. The cab is an awful lot safer with those sort of powers if you use an HPF at 50Hz or even higher. The output is very limited below 80Hz by design so there's no point letting anything through below that. The coil may have been smacking against the back of the magnet and if it over excurts (is that a word?) it loses the cooling effect of being in the magnetic gap. If i'm playing that loud I pretty much always put the cab right in a corner and roll off the bass which corner placing reinforces. I'm glad it's mended, the BAM will be a perfect match and does have some bass roll off built in which helps.

Btw they are also selling the RCF AYRA Pro5 studio monitors for £89. That's mad for decent studio monitors that will take bass at pretty high volumes (I've rehearsed with mine) and which sound not far short of my moderately expensive hi-fi

I'm so tempted at that price. Get ye behind me!

Ain't that the truth! The trouble is that they watch too many videos and copy the moves. It's quite fun watching some live video and picking out when you are listening to a recording or one of the backing singers. I've spotted Kylie's live videos where she has dropped the mic down to her knee and the vocal continues with no change in volume or timbre. Trying to persuade a singer to watch mic technique on genuinely live video seems to be like asking them to read War and Peace.

I've done that twice recently one of the downsides of in-ears is that you have this magnificent sound the moment you crash into the first song but only you can hear it. OOps 🙄